Return to orignal label.

.gitea/workflows/build.yaml

@@ -0,0 +1,11 @@
+---
+name: MoreThanText build
+run-name: ${{ gitea.actor }} runner
+on: push
+
+jobs:
+  Build-MoreThanText:
+    runs-on: ubuntu-latest
+    steps:
+      - run: cargo test
+      - run: cargo build --release

Pipfile

@@ -11,4 +11,4 @@ black = "*"
 pylint = "*"
 
 [requires]
-python_version = "3.9"
+python_version = "3"

src/main.rs

@@ -7,7 +7,7 @@ use tide::{
 mod morethantext;
 mod settings;
 
-use morethantext::MoreThanText;
+use morethantext::{start_db, MoreThanText};
 use settings::Settings;
 
 #[async_std::main]
@@ -20,7 +20,7 @@ async fn main() -> tide::Result<()> {
 }
 
 async fn app_setup(data_dir: &str) -> tide::Server<MoreThanText> {
-    let db = MoreThanText::new(data_dir).await.unwrap();
+    let db = start_db(data_dir).await.unwrap();
     let mut app = tide::with_state(db);
     app.at("/").get(home);
     app.with(

src/morethantext/cache.rs

@@ -0,0 +1,336 @@
+use super::{Database, ErrorCode, FromCache, MTTError, Store, ToCache, ENTRY};
+use async_std::{channel::Receiver, path::PathBuf};
+use rand::{distributions::Alphanumeric, thread_rng, Rng};
+use std::{
+    collections::{HashMap, VecDeque},
+    iter::Iterator,
+};
+
+struct IDGenerator {
+    ids: Option<VecDeque<String>>,
+}
+
+impl IDGenerator {
+    fn new() -> Self {
+        Self { ids: None }
+    }
+
+    fn with_ids<T, D>(ids: T) -> Self
+    where
+        T: Into<Vec<D>>,
+        D: Into<String>,
+    {
+        let id_list = ids.into();
+        let mut data = VecDeque::new();
+        for id in id_list {
+            data.push_back(id.into());
+        }
+        Self { ids: Some(data) }
+    }
+}
+
+impl Iterator for IDGenerator {
+    type Item = String;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match &self.ids {
+            Some(id_list) => {
+                let mut ids = id_list.clone();
+                let output = ids.pop_front();
+                self.ids = Some(ids);
+                output
+            }
+            None => Some(thread_rng().sample_iter(&Alphanumeric).take(64).collect()),
+        }
+    }
+}
+
+#[cfg(test)]
+mod genid {
+    use super::*;
+
+    #[test]
+    fn unique_ids() {
+        let mut gen = IDGenerator::new();
+        let mut output: Vec<String> = Vec::new();
+        for _ in 0..10 {
+            let id = gen.next().unwrap();
+            assert!(!output.contains(&id), "{} found in {:?}", id, output);
+            output.push(id);
+        }
+    }
+
+    #[test]
+    fn controlled_ids() {
+        let ids = ["one", "two", "three"];
+        let mut gen = IDGenerator::with_ids(ids.clone());
+        for id in ids {
+            assert_eq!(id, gen.next().unwrap());
+        }
+    }
+}
+
+pub struct Cache {
+    data: HashMap<String, FromCache>,
+    ids: IDGenerator,
+}
+
+impl Cache {
+    pub async fn new<P>(_dir: P) -> Self
+    where
+        P: Into<PathBuf>,
+    {
+        let mut data = HashMap::new();
+        data.insert(ENTRY.to_string(), FromCache::Str(Store::new()));
+        Self {
+            data: data,
+            ids: IDGenerator::new(),
+        }
+    }
+
+    async fn with_ids<P, T, D>(dir: P, ids: T) -> Self
+    where
+        P: Into<PathBuf>,
+        T: Into<Vec<D>>,
+        D: Into<String>,
+    {
+        let mut output = Self::new(dir).await;
+        output.ids = IDGenerator::with_ids(ids);
+        output
+    }
+
+    fn next_id(&mut self) -> String {
+        let mut id: String;
+        loop {
+            id = self.ids.next().unwrap();
+            match self.get(&id) {
+                FromCache::Error(_) => break,
+                _ => (),
+            }
+        }
+        id
+    }
+
+    pub async fn listen(&mut self, listener: Receiver<ToCache>) {
+        loop {
+            match listener.recv().await.unwrap() {
+                ToCache::Get(data) => {
+                    data.result.send(self.get(data.data)).await.unwrap();
+                }
+                ToCache::Commit(data) => {
+                    data.result.send(self.commit(data.data)).await.unwrap();
+                }
+            }
+        }
+    }
+
+    pub fn get<S>(&self, id: S) -> FromCache
+    where
+        S: Into<String>,
+    {
+        let idd = id.into();
+        match self.data.get(&idd) {
+            Some(data) => data.clone(),
+            None => FromCache::Error(MTTError::from_code(ErrorCode::IDNotFound(idd))),
+        }
+    }
+
+    pub fn commit(&mut self, data: Store) -> FromCache {
+        let entry_data = self.data.get(ENTRY).unwrap();
+        let mut store = match entry_data {
+            FromCache::Str(ep) => ep.clone(),
+            _ => {
+                unreachable!()
+            }
+        };
+        for name in data.list() {
+            let id = self.next_id();
+            match store.add_by_id(name, &id) {
+                Ok(_) => {
+                    self.data.insert(id, FromCache::DB(Database::new()));
+                }
+                Err(err) => return FromCache::Error(err),
+            }
+        }
+        self.data
+            .insert(ENTRY.to_string(), FromCache::Str(store))
+            .unwrap();
+        FromCache::Ok
+    }
+}
+
+#[cfg(test)]
+mod engine {
+    use super::*;
+    use tempfile::tempdir;
+
+    #[async_std::test]
+    async fn get_entry() {
+        let dir = tempdir().unwrap();
+        let cache = Cache::new(dir.path()).await;
+        let expected: Vec<String> = Vec::new();
+        let result = cache.get(ENTRY);
+        match result {
+            FromCache::Str(store) => assert_eq!(store.list(), expected),
+            _ => assert!(false, "{:?} should be FromCache::Str", result),
+        }
+    }
+
+    #[async_std::test]
+    async fn get_bad_entry() -> Result<(), MTTError> {
+        let dir = tempdir().unwrap();
+        let cache = Cache::new(dir.path()).await;
+        let ids = ["bad1", "bad2"];
+        for id in ids {
+            let output = cache.get(id);
+            match output {
+                FromCache::Error(err) => match err.code {
+                    ErrorCode::IDNotFound(_) => {
+                        assert!(
+                            err.to_string().contains(id),
+                            "Had error: {}, Did not contain: {}",
+                            err.to_string(),
+                            id
+                        );
+                    }
+                    _ => return Err(MTTError::new(format!("{:?} is not IDNotFound", err.code))),
+                },
+                _ => {
+                    return Err(MTTError::new(format!(
+                        "{:?} is not FromCache::Error",
+                        output
+                    )))
+                }
+            }
+        }
+        Ok(())
+    }
+
+    #[async_std::test]
+    async fn commit_database() {
+        // remove this one for the one below, maybe.
+        let dir = tempdir().unwrap();
+        let mut cache = Cache::new(dir.path()).await;
+        let mut store = Store::new();
+        let db = "garfield";
+        store.add(db).unwrap();
+        cache.commit(store.clone());
+        let output = cache.get(ENTRY);
+        match output {
+            FromCache::Str(result) => assert_eq!(result.list(), store.list()),
+            _ => assert!(false, "{:?} is not FromCache::Str", output),
+        }
+    }
+
+    #[async_std::test]
+    async fn add_database_entry() {
+        let id = "an_id";
+        let name = "garfield";
+        let dir = tempdir().unwrap();
+        let mut cache = Cache::with_ids(dir.path(), [id]).await;
+        let mut store = Store::new();
+        store.add(name).unwrap();
+        cache.commit(store.clone());
+        let db_out = cache.get(id);
+        match db_out {
+            FromCache::DB(_) => (),
+            _ => assert!(
+                false,
+                "{:?} is not FromCache::DB -- cache is {:?}",
+                db_out, cache.data
+            ),
+        }
+        let store_out = cache.get(ENTRY);
+        match store_out {
+            FromCache::Str(updated_store) => match updated_store.get(name) {
+                Some(output) => {
+                    assert_eq!(output.id, Some(id.to_string()));
+                    assert!(output.data.is_none(), "Should have removed the database.");
+                }
+                None => assert!(true, "Store should have stored the database."),
+            },
+            _ => assert!(
+                false,
+                "{:?} is not FromCache::Str -- cache is {:?}",
+                db_out, cache.data
+            ),
+        }
+    }
+
+    #[async_std::test]
+    async fn ids_are_not_overwritten() {
+        let ids = ["first", "first", "second"];
+        let names = ["barney", "fred"];
+        let dir = tempdir().unwrap();
+        let mut cache = Cache::with_ids(dir.path(), ids).await;
+        let mut store1 = Store::new();
+        store1.add(names[0]).unwrap();
+        let mut store2 = Store::new();
+        store2.add(names[1]).unwrap();
+        cache.commit(store1);
+        cache.commit(store2);
+        assert_eq!(
+            cache.data.len(),
+            3,
+            "cache.data had the following entries {:?}",
+            cache.data.keys()
+        );
+    }
+
+    #[async_std::test]
+    async fn no_duplicate_ids() {
+        let ids = ["one", "two"];
+        let dir = tempdir().unwrap();
+        let mut cache = Cache::with_ids(dir.path(), ids).await;
+        cache
+            .data
+            .insert(ids[0].to_string(), FromCache::DB(Database::new()));
+        assert_eq!(cache.next_id(), ids[1]);
+    }
+}
+
+#[cfg(test)]
+mod messages {
+    use super::{
+        super::{start_db, ToCacheMsg},
+        *,
+    };
+    use async_std::channel::unbounded;
+    use tempfile::tempdir;
+
+    #[async_std::test]
+    async fn get_the_store() {
+        let dir = tempdir().unwrap();
+        let mtt = start_db(dir.path()).await.unwrap();
+        let in_s = mtt.to_cache.clone();
+        let (out_s, out_r) = unbounded();
+        let msg = ToCacheMsg {
+            data: ENTRY.to_string(),
+            result: out_s,
+        };
+        in_s.send(ToCache::Get(msg)).await.unwrap();
+        let result = out_r.recv().await.unwrap();
+        match result {
+            FromCache::Str(_) => (),
+            _ => assert!(false, "{:?} is not FromCache::Str", result),
+        }
+    }
+
+    #[async_std::test]
+    async fn get_bad_id() {
+        let dir = tempdir().unwrap();
+        let mtt = start_db(dir.path()).await.unwrap();
+        let in_s = mtt.to_cache.clone();
+        let (out_s, out_r) = unbounded();
+        let msg = ToCacheMsg {
+            data: "bad_id!".to_string(),
+            result: out_s,
+        };
+        in_s.send(ToCache::Get(msg)).await.unwrap();
+        let output = out_r.recv().await.unwrap();
+        match output {
+            FromCache::Error(_) => (),
+            _ => assert!(false, "{:?} is not FromCache::Error", output),
+        }
+    }
+}

src/morethantext/database-old.rs

@@ -0,0 +1,36 @@
+use super::{DBError, FileData, SessionData};
+use std::slice;
+
+#[derive(Clone)]
+pub struct Database;
+
+impl Database {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl FileData<Self> for Database {
+    fn to_bytes(&self) -> Vec<u8> {
+        let output = Vec::new();
+        output
+    }
+
+    fn from_bytes(_data: &mut slice::Iter<u8>) -> Result<Self, DBError> {
+        Ok(Self {})
+    }
+}
+
+impl SessionData for Database {
+    fn add(&mut self, _key: &str, _value: &str, _data: &str) -> Result<Vec<String>, DBError> {
+        Ok(Vec::new())
+    }
+
+    fn eq(&self, _key: &str, _value: &str) -> Result<Vec<String>, DBError> {
+        Ok(Vec::new())
+    }
+
+    fn list(&self, _keys: Vec<&str>) -> Result<Vec<String>, DBError> {
+        Ok(Vec::new())
+    }
+}

src/morethantext/database.rs

@@ -0,0 +1,171 @@
+use super::{Data, ErrorCode, MTTError, Table};
+use std::collections::HashMap;
+
+#[derive(Clone, Debug)]
+pub struct Database {
+    data: HashMap<String, Data<Table>>,
+}
+
+impl Database {
+    pub fn new() -> Self {
+        Self {
+            data: HashMap::new(),
+        }
+    }
+
+    pub fn add<S>(&mut self, name: S) -> Result<(), MTTError>
+    where
+        S: Into<String>,
+    {
+        let db_name = name.into();
+        match self.get(&db_name) {
+            Some(_) => Err(MTTError::from_code(ErrorCode::DuplicateTable(db_name))),
+            None => {
+                self.data.insert(db_name, Data::from_data(Table::new()));
+                Ok(())
+            }
+        }
+    }
+
+    pub fn add_by_id<S, D>(&mut self, name: S, id: D) -> Result<(), MTTError>
+    where
+        S: Into<String>,
+        D: Into<String>,
+    {
+        let db_name = name.into();
+        match self.get(&db_name) {
+            Some(_) => Err(MTTError::from_code(ErrorCode::DuplicateTable(db_name))),
+            None => {
+                self.data.insert(db_name, Data::from_id(id.into()));
+                Ok(())
+            }
+        }
+    }
+
+    pub fn get(&self, name: &str) -> Option<&Data<Table>> {
+        self.data.get(name)
+    }
+
+    pub fn list(&self) -> Vec<String> {
+        let mut names = Vec::new();
+        for name in self.data.keys() {
+            names.push(name.to_string());
+        }
+        names.sort();
+        names
+    }
+}
+
+#[cfg(test)]
+mod databases {
+    use super::*;
+
+    #[test]
+    fn create_new() {
+        let db = Database::new();
+        let expected: Vec<String> = Vec::new();
+        assert_eq!(db.list(), expected);
+    }
+
+    #[test]
+    fn add_db_by_str() {
+        let mut db = Database::new();
+        let name = "Melvin";
+        db.add(name).unwrap();
+        let output = db.get(name);
+        assert!(output.is_some(), "Get returned none.");
+    }
+
+    #[test]
+    fn add_db_by_string() {
+        let mut db = Database::new();
+        let name = "Marvin";
+        db.add(name.to_string()).unwrap();
+        let output = db.get(name);
+        assert!(output.is_some(), "Get returned none.");
+    }
+
+    #[test]
+    fn fail_on_duplicates() -> Result<(), MTTError> {
+        let mut db = Database::new();
+        let name = "Mickie";
+        db.add(name).unwrap();
+        match db.add(name) {
+            Ok(_) => Err(MTTError::new("duplicates should error")),
+            Err(err) => match err.code {
+                ErrorCode::DuplicateTable(db_name) => {
+                    assert_eq!(db_name, name);
+                    Ok(())
+                }
+                _ => Err(MTTError::new(format!("{:?} is not DuplicateTable", err))),
+            },
+        }
+    }
+
+    #[test]
+    fn add_using_cache_id() {
+        let mut db = Database::new();
+        let name = "fred";
+        let id = "12345";
+        db.add_by_id(name, id).unwrap();
+        let output = db.get(name).unwrap();
+        assert!(output.data.is_none(), "there should be no data");
+        assert_eq!(output.id, Some(id.to_string()));
+    }
+
+    #[test]
+    fn add_by_cache_id_name_string() {
+        let mut db = Database::new();
+        let name = "barney";
+        let id = "67890";
+        db.add_by_id(name.to_string(), id).unwrap();
+        let output = db.get(name).unwrap();
+        assert!(output.data.is_none(), "there should be no data");
+        assert_eq!(output.id, Some(id.to_string()));
+    }
+
+    #[test]
+    fn no_duplicate_databases_for_add_by_id() {
+        let mut db = Database::new();
+        let name = "betty";
+        db.add_by_id(name, "fghij").unwrap();
+        match db.add_by_id(name, "klmno") {
+            Ok(_) => assert!(false, "Duplicates should error."),
+            Err(err) => match err.code {
+                ErrorCode::DuplicateTable(db_name) => assert_eq!(db_name, name),
+                _ => assert!(false, "{:?} is not DuplicateTable", err),
+            },
+        }
+    }
+
+    #[test]
+    fn add_by_cache_id_string() {
+        let mut db = Database::new();
+        let name = "wilma";
+        let id = "abcdef";
+        db.add_by_id(name, id.to_string()).unwrap();
+        let output = db.get(name).unwrap();
+        assert!(output.data.is_none(), "there should be no data");
+        assert_eq!(output.id, Some(id.to_string()));
+    }
+
+    #[test]
+    fn get_bad_database() -> Result<(), MTTError> {
+        let db = Database::new();
+        match db.get("missing") {
+            Some(_) => Err(MTTError::new("Should have returned None.")),
+            None => Ok(()),
+        }
+    }
+
+    #[test]
+    fn get_list() {
+        let mut db = Database::new();
+        let mut ids = ["one", "two", "three", "four", "five"];
+        for name in ids {
+            db.add(name.to_string()).unwrap();
+        }
+        ids.sort();
+        assert_eq!(db.list(), ids);
+    }
+}

src/morethantext/entry.rs

@@ -0,0 +1,381 @@
+use super::{DBError, DataType, ErrorCode, FileData, SessionData};
+use async_std::{
+    fs::{read, remove_file, write},
+    path::PathBuf,
+};
+use std::{
+    cell::Cell,
+    time::{Duration, Instant},
+};
+
+pub struct Entry {
+    data: DataType,
+    filename: PathBuf,
+    last_used: Cell<Instant>,
+}
+
+impl Entry {
+    pub async fn new<P>(filename: P, data: DataType) -> Result<Self, DBError>
+    where
+        P: Into<PathBuf>,
+    {
+        let pathbuf = filename.into();
+        if pathbuf.as_path().exists().await {
+            return Err(DBError::from_code(ErrorCode::EntryExists(pathbuf)));
+        } else {
+            match write(&pathbuf, data.to_bytes()).await {
+                Ok(_) => (),
+                Err(err) => {
+                    let mut error = DBError::from_code(ErrorCode::EntryWriteFailure(pathbuf));
+                    error.add_source(err);
+                    return Err(error);
+                }
+            }
+        }
+        Ok(Self {
+            data: data,
+            filename: pathbuf,
+            last_used: Cell::new(Instant::now()),
+        })
+    }
+
+    pub async fn get<P>(filename: P) -> Result<Self, DBError>
+    where
+        P: Into<PathBuf>,
+    {
+        let pathbuf = filename.into();
+        let content = match read(&pathbuf).await {
+            Ok(text) => text,
+            Err(err) => {
+                let mut error = DBError::from_code(ErrorCode::EntryReadFailure(pathbuf));
+                error.add_source(err);
+                return Err(error);
+            }
+        };
+        let data = match DataType::from_bytes(&mut content.iter()) {
+            Ok(raw) => raw,
+            Err(err) => {
+                let mut error = DBError::from_code(ErrorCode::EntryReadFailure(pathbuf));
+                error.add_source(err);
+                return Err(error);
+            }
+        };
+        Ok(Self {
+            data: data,
+            filename: pathbuf,
+            last_used: Cell::new(Instant::now()),
+        })
+    }
+
+    pub fn elapsed(&self) -> Duration {
+        self.last_used.get().elapsed()
+    }
+
+    pub fn data(&self) -> DataType {
+        self.last_used.set(Instant::now());
+        self.data.clone()
+    }
+
+    async fn update(&mut self, data: DataType) -> Result<(), DBError> {
+        self.last_used.set(Instant::now());
+        match write(&self.filename, data.to_bytes()).await {
+            Ok(_) => (),
+            Err(err) => {
+                let mut error =
+                    DBError::from_code(ErrorCode::EntryWriteFailure(self.filename.clone()));
+                error.add_source(err);
+                return Err(error);
+            }
+        };
+        self.data = data;
+        Ok(())
+    }
+
+    async fn remove(&self) -> Result<(), DBError> {
+        match remove_file(&self.filename).await {
+            Ok(_) => Ok(()),
+            Err(err) => {
+                let mut error =
+                    DBError::from_code(ErrorCode::EntryDeleteFailure(self.filename.clone()));
+                error.add_source(err);
+                Err(error)
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod entry {
+    use super::*;
+    use std::error::Error;
+    use tempfile::tempdir;
+
+    #[async_std::test]
+    async fn get_elapsed_time() {
+        let dir = tempdir().unwrap();
+        let data = DataType::new("store").unwrap();
+        let filepath = dir.path().join("count");
+        let filename = filepath.to_str().unwrap();
+        let item = Entry::new(filename.to_string(), data).await.unwrap();
+        assert!(
+            Duration::from_secs(1) > item.elapsed(),
+            "last_used should have been now."
+        );
+        item.last_used
+            .set(Instant::now() - Duration::from_secs(500));
+        assert!(
+            Duration::from_secs(499) < item.elapsed(),
+            "The duration should have increased."
+        );
+    }
+
+    #[async_std::test]
+    async fn create() {
+        let dir = tempdir().unwrap();
+        let mut data = DataType::new("store").unwrap();
+        data.add("database", "roger", "moore").unwrap();
+        let filepath = dir.path().join("wiliam");
+        let filename = filepath.to_str().unwrap();
+        let item = Entry::new(filename.to_string(), data.clone())
+            .await
+            .unwrap();
+        assert!(
+            Duration::from_secs(1) > item.elapsed(),
+            "last_used should have been now."
+        );
+        let output = item.data();
+        assert_eq!(
+            data.list(["database"].to_vec()).unwrap(),
+            output.list(["database"].to_vec()).unwrap()
+        );
+        assert!(filepath.is_file(), "Should have created the entry file.");
+        let content = read(&filepath).await.unwrap();
+        assert_eq!(content, data.to_bytes());
+    }
+
+    #[async_std::test]
+    async fn create_errors_on_bad_files() -> Result<(), DBError> {
+        let dir = tempdir().unwrap();
+        let data = DataType::new("store").unwrap();
+        let filepath = dir.path().join("bad").join("path");
+        let filename = filepath.to_str().unwrap();
+        match Entry::new(filename.to_string(), data).await {
+            Ok(_) => Err(DBError::new("bad file names should raise an error")),
+            Err(err) => match err.code {
+                ErrorCode::EntryWriteFailure(_) => {
+                    assert!(err.source().is_some(), "Must include the source error.");
+                    assert!(err
+                        .source()
+                        .unwrap()
+                        .to_string()
+                        .contains("could not write to file"));
+                    Ok(())
+                }
+                _ => Err(DBError::new("incorrect error code")),
+            },
+        }
+    }
+
+    #[async_std::test]
+    async fn create_does_not_over_writes() -> Result<(), DBError> {
+        let dir = tempdir().unwrap();
+        let id = "wicked";
+        let file = dir.path().join(id);
+        let filename = file.to_str().unwrap();
+        write(&file, b"previous").await.unwrap();
+        let data = DataType::new("store").unwrap();
+        match Entry::new(filename.to_string(), data).await {
+            Ok(_) => {
+                return Err(DBError::new(
+                    "Should produce an error for an existing Entry",
+                ))
+            }
+            Err(err) => match err.code {
+                ErrorCode::EntryExists(_) => Ok(()),
+                _ => Err(DBError::new("incorrect error code")),
+            },
+        }
+    }
+
+    #[async_std::test]
+    async fn get_updates_last_used() {
+        let dir = tempdir().unwrap();
+        let data = DataType::new("store").unwrap();
+        let filepath = dir.path().join("holder");
+        let filename = filepath.to_str().unwrap();
+        let item = Entry::new(filename.to_string(), data).await.unwrap();
+        item.last_used
+            .set(Instant::now() - Duration::from_secs(300));
+        item.data();
+        assert!(
+            Duration::from_secs(1) > item.elapsed(),
+            "last_used should have been reset."
+        );
+    }
+
+    #[async_std::test]
+    async fn update_entry() {
+        let dir = tempdir().unwrap();
+        let mut data = DataType::new("store").unwrap();
+        let filepath = dir.path().join("changing");
+        let filename = filepath.to_str().unwrap();
+        let mut item = Entry::new(filename.to_string(), data.clone())
+            .await
+            .unwrap();
+        item.last_used
+            .set(Instant::now() - Duration::from_secs(500));
+        data.add("database", "new", "stuff").unwrap();
+        item.update(data.clone()).await.unwrap();
+        assert!(
+            Duration::from_secs(1) > item.elapsed(),
+            "last_used should have been reset."
+        );
+        let output = item.data();
+        assert_eq!(
+            data.list(["database"].to_vec()).unwrap(),
+            output.list(["database"].to_vec()).unwrap()
+        );
+        let content = read(&filepath).await.unwrap();
+        assert_eq!(content, data.to_bytes());
+    }
+
+    #[async_std::test]
+    async fn update_write_errors() -> Result<(), DBError> {
+        let dir = tempdir().unwrap();
+        let data = DataType::new("store").unwrap();
+        let filepath = dir.path().join("changing");
+        let filename = filepath.to_str().unwrap();
+        let mut item = Entry::new(filename.to_string(), data.clone())
+            .await
+            .unwrap();
+        drop(dir);
+        match item.update(data).await {
+            Ok(_) => Err(DBError::new("file writes should return an error")),
+            Err(err) => match err.code {
+                ErrorCode::EntryWriteFailure(_) => {
+                    assert!(err.source().is_some(), "Must include the source error.");
+                    assert!(err
+                        .source()
+                        .unwrap()
+                        .to_string()
+                        .contains("could not write to file"));
+                    Ok(())
+                }
+                _ => Err(DBError::new("incorrect error code")),
+            },
+        }
+    }
+
+    #[async_std::test]
+    async fn retrieve() {
+        let dir = tempdir().unwrap();
+        let mut data = DataType::new("store").unwrap();
+        data.add("database", "something_old", "3.14159").unwrap();
+        let filepath = dir.path().join("existing");
+        let filename = filepath.to_str().unwrap();
+        let item = Entry::new(filename.to_string(), data.clone())
+            .await
+            .unwrap();
+        let output = Entry::get(filename).await.unwrap();
+        assert_eq!(
+            output.data().list(["database"].to_vec()).unwrap(),
+            data.list(["database"].to_vec()).unwrap()
+        );
+        assert_eq!(output.filename.to_str().unwrap(), filename);
+        assert!(
+            Duration::from_secs(1) > item.elapsed(),
+            "last_used should have been reset."
+        );
+    }
+
+    #[async_std::test]
+    async fn retrieve_file_missing() -> Result<(), DBError> {
+        let dir = tempdir().unwrap();
+        let filepath = dir.path().join("justnotthere");
+        let filename = filepath.to_str().unwrap();
+        match Entry::get(filename).await {
+            Ok(_) => Err(DBError::new("should have returned an error")),
+            Err(err) => match err.code {
+                ErrorCode::EntryReadFailure(_) => {
+                    assert!(err.source().is_some(), "Error should have a source.");
+                    assert!(
+                        err.source()
+                            .unwrap()
+                            .to_string()
+                            .contains("could not read file"),
+                        "Source Error Message: {}",
+                        err.source().unwrap().to_string()
+                    );
+                    Ok(())
+                }
+                _ => Err(DBError::new("incorrect error code")),
+            },
+        }
+    }
+
+    #[async_std::test]
+    async fn retrieve_corrupt_file() -> Result<(), DBError> {
+        let dir = tempdir().unwrap();
+        let filepath = dir.path().join("garbage");
+        let filename = filepath.to_str().unwrap();
+        write(&filepath, b"jhsdfghlsdf").await.unwrap();
+        match Entry::get(filename).await {
+            Ok(_) => Err(DBError::new("should have returned an error")),
+            Err(err) => match err.code {
+                ErrorCode::EntryReadFailure(_) => {
+                    assert!(err.source().is_some(), "Error should have a source.");
+                    assert!(
+                        err.source().unwrap().to_string().contains("corrupt file"),
+                        "Source Error Message: {}",
+                        err.source().unwrap().to_string()
+                    );
+                    Ok(())
+                }
+                _ => Err(DBError::new("incorrect error code")),
+            },
+        }
+    }
+
+    #[async_std::test]
+    async fn delete() {
+        let dir = tempdir().unwrap();
+        let filepath = dir.path().join("byebye");
+        let filename = filepath.to_str().unwrap();
+        let data = DataType::new("store").unwrap();
+        let item = Entry::new(filename.to_string(), data.clone())
+            .await
+            .unwrap();
+        item.remove().await.unwrap();
+        assert!(!filepath.exists(), "Entry file should be removed.");
+    }
+
+    #[async_std::test]
+    async fn delete_bad_file() -> Result<(), DBError> {
+        let dir = tempdir().unwrap();
+        let filepath = dir.path().join("itsnotthere");
+        let filename = filepath.to_str().unwrap();
+        let data = DataType::new("store").unwrap();
+        let item = Entry::new(filename.to_string(), data.clone())
+            .await
+            .unwrap();
+        remove_file(filename).await.unwrap();
+        match item.remove().await {
+            Ok(_) => Err(DBError::new("should have produced an error")),
+            Err(err) => match err.code {
+                ErrorCode::EntryDeleteFailure(_) => {
+                    assert!(err.source().is_some(), "Error should have a source.");
+                    assert!(
+                        err.source()
+                            .unwrap()
+                            .to_string()
+                            .contains("could not remove file"),
+                        "Source Error Message: {}",
+                        err.source().unwrap().to_string()
+                    );
+                    Ok(())
+                }
+                _ => Err(DBError::new("incorrect error code")),
+            },
+        }
+    }
+}

src/morethantext/error.rs

@@ -1,90 +1,135 @@
 use std::{error::Error, fmt};
 
-#[derive(Debug)]
-pub struct DBError {
-    msg: String,
-    src: Option<Box<dyn Error + 'static>>,
+#[derive(Clone, Debug)]
+pub enum ErrorCode {
+    // General
+    Undefined(String),
+    // Cache
+    IDNotFound(String),
+    // Store
+    DuplicateDatabase(String),
+    // Database
+    DuplicateTable(String),
 }
 
-impl DBError {
+impl fmt::Display for ErrorCode {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            ErrorCode::Undefined(msg) => write!(f, "{}", msg),
+            ErrorCode::IDNotFound(id) => write!(f, "ID '{}' not found", id),
+            ErrorCode::DuplicateDatabase(name) => write!(f, "database '{}' already exists", name),
+            ErrorCode::DuplicateTable(name) => write!(f, "table '{}' already exists", name),
+        }
+    }
+}
+
+mod errorcodes {
+    use super::*;
+
+    const ITEMS: [&str; 2] = ["one", "two"];
+
+    #[test]
+    fn undefined_display() {
+        for item in ITEMS {
+            let err = ErrorCode::Undefined(item.to_string());
+            assert_eq!(err.to_string(), item);
+        }
+    }
+
+    #[test]
+    fn cache_missing() {
+        for item in ITEMS {
+            let err = ErrorCode::IDNotFound(item.to_string());
+            assert_eq!(err.to_string(), format!("ID '{}' not found", item));
+        }
+    }
+
+    #[test]
+    fn duplicate_database() {
+        for item in ITEMS {
+            let err = ErrorCode::DuplicateDatabase(item.to_string());
+            assert_eq!(
+                err.to_string(),
+                format!("database '{}' already exists", item)
+            );
+        }
+    }
+
+    #[test]
+    fn duplicate_table() {
+        for item in ITEMS {
+            let err = ErrorCode::DuplicateTable(item.to_string());
+            assert_eq!(err.to_string(), format!("table '{}' already exists", item));
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct MTTError {
+    pub code: ErrorCode,
+}
+
+impl MTTError {
     pub fn new<S>(msg: S) -> Self
     where
         S: Into<String>,
     {
+        let text = msg.into();
         Self {
-            msg: msg.into(),
-            src: None,
+            code: ErrorCode::Undefined(text),
         }
     }
 
-    pub fn add_source<E>(&mut self, src: E)
-    where
-        E: Error + 'static,
-    {
-        self.src = Some(Box::new(src));
+    pub fn from_code(code: ErrorCode) -> Self {
+        Self { code: code }
     }
 }
 
-impl Error for DBError {
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        match &self.src {
-            Some(err) => Some(err.as_ref()),
-            None => None,
-        }
-    }
-}
+impl Error for MTTError {}
 
-impl fmt::Display for DBError {
+impl fmt::Display for MTTError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{}", self.msg)
+        write!(f, "{}", self.code)
     }
 }
 
 #[cfg(test)]
-mod create {
+mod errors {
     use super::*;
 
     #[test]
-    fn with_str() {
-        let msg = "something happened";
-        let err = DBError::new(msg);
-        assert!(
-            err.to_string() == msg,
-            "Got: {} -- Want: {}",
-            err.to_string(),
-            msg
-        );
-        assert!(
-            err.source().is_none(),
-            "Error should initialize with no source."
-        );
+    fn create_with_str() {
+        let msgs = ["one", "two"];
+        for msg in msgs {
+            let err = MTTError::new(msg);
+            assert_eq!(err.to_string(), msg);
+        }
     }
 
     #[test]
-    fn with_string() {
-        let msg = "it went boom".to_string();
-        let err = DBError::new(msg.clone());
-        assert!(
-            err.to_string() == msg,
-            "Got: {} -- Want: {}",
-            err.to_string(),
-            msg
-        );
-        assert!(
-            err.source().is_none(),
-            "Error should initialize with no source."
-        );
+    fn create_with_string() {
+        let msg = "three";
+        let err = MTTError::new(msg.to_string());
+        assert_eq!(err.to_string(), msg);
     }
 
     #[test]
-    fn with_source() {
-        let msg = "but this caused the problem";
-        let mut par = DBError::new("parent error");
-        let src = DBError::new(msg);
-        par.add_source(src);
-        let output = par.source();
-        assert!(output.is_some(), "Should return source.");
-        let source = output.unwrap();
-        assert!(source.to_string() == msg);
+    fn create_from_code() {
+        let code = ErrorCode::Undefined("oops".to_string());
+        let err = MTTError::from_code(code);
+        match err.code {
+            ErrorCode::Undefined(_) => (),
+            _ => assert!(false, "{:?} is not undefined", err.code),
+        }
+    }
+
+    #[test]
+    fn create_missing_id_from_code() {
+        let code = ErrorCode::IDNotFound("123".to_string());
+        let err = MTTError::from_code(code);
+        match err.code {
+            ErrorCode::IDNotFound(_) => (),
+            _ => assert!(false, "{:?} is not undefined", err.code),
+        }
     }
 }

src/morethantext/mod-2.rs

@@ -0,0 +1,402 @@
+mod database;
+mod entry;
+mod error;
+mod store;
+
+use async_std::path::PathBuf;
+use database::Database;
+use entry::Entry;
+use error::{DBError, ErrorCode};
+use rand::{distributions::Alphanumeric, thread_rng, Rng};
+use std::{slice, str};
+use store::Store;
+
+const ENTRY: &str = "EntryPoint";
+
+trait ID {
+    fn next(&self) -> String;
+}
+
+trait FileData<F> {
+    fn to_bytes(&self) -> Vec<u8>;
+    fn from_bytes(data: &mut slice::Iter<u8>) -> Result<F, DBError>;
+}
+
+trait SessionData {
+    fn add(&mut self, key: &str, value: &str, data: &str) -> Result<Vec<String>, DBError>;
+    fn eq(&self, key: &str, value: &str) -> Result<Vec<String>, DBError>;
+    fn list(&self, keys: Vec<&str>) -> Result<Vec<String>, DBError>;
+}
+
+#[derive(Clone)]
+pub enum DataType {
+    DBMap(Store),
+    TableMap(Database),
+}
+
+impl DataType {
+    fn new(data_type: &str) -> Result<Self, DBError> {
+        match data_type {
+            "store" => Ok(DataType::DBMap(Store::new())),
+            "database" => Ok(DataType::TableMap(Database::new())),
+            _ => Err(DBError::from_code(ErrorCode::DataTypeIncorrect(
+                data_type.to_string(),
+            ))),
+        }
+    }
+}
+
+impl SessionData for DataType {
+    fn add(&mut self, key: &str, value: &str, data: &str) -> Result<Vec<String>, DBError> {
+        match self {
+            DataType::DBMap(dbs) => dbs.add(key, value, data),
+            DataType::TableMap(_) => todo!(),
+        }
+    }
+
+    fn eq(&self, key: &str, value: &str) -> Result<Vec<String>, DBError> {
+        match self {
+            DataType::DBMap(dbs) => dbs.eq(key, value),
+            DataType::TableMap(_) => todo!(),
+        }
+    }
+
+    fn list(&self, keys: Vec<&str>) -> Result<Vec<String>, DBError> {
+        match self {
+            DataType::DBMap(dbs) => dbs.list(keys),
+            DataType::TableMap(_) => todo!(),
+        }
+    }
+}
+
+impl FileData<Self> for DataType {
+    fn to_bytes(&self) -> Vec<u8> {
+        let mut output = Vec::new();
+        match self {
+            DataType::DBMap(_) => output.append(&mut "DBMap".as_bytes().to_vec()),
+            DataType::TableMap(_) => output.append(&mut "TableMap".as_bytes().to_vec()),
+        }
+        output.push(0);
+        match self {
+            DataType::DBMap(store) => output.append(&mut store.to_bytes()),
+            DataType::TableMap(_) => (),
+        }
+        output
+    }
+
+    fn from_bytes(data: &mut slice::Iter<u8>) -> Result<Self, DBError> {
+        let mut header: Vec<u8> = Vec::new();
+        loop {
+            let letter = match data.next() {
+                Some(a) => a.clone(),
+                None => 0,
+            };
+            if letter == 0 {
+                break;
+            } else {
+                header.push(letter);
+            }
+        }
+        let header = match str::from_utf8(&header) {
+            Ok(item) => item,
+            Err(_) => return Err(DBError::from_code(ErrorCode::CorruptFile)),
+        };
+        match header {
+            "DBMap" => match Store::from_bytes(data) {
+                Ok(store) => Ok(DataType::DBMap(store)),
+                Err(err) => Err(err),
+            },
+            "TableMap" => Ok(DataType::new("database").unwrap()),
+            _ => Err(DBError::from_code(ErrorCode::CorruptFile)),
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct MoreThanText {
+    next_id: &dyn Fn() -> String,
+    session: Vec<String>,
+}
+
+impl MoreThanText {
+    pub async fn new<P>(dir: P) -> Result<Self, DBError>
+    where
+        P: Into<PathBuf>,
+    {
+        let pathbuf = dir.into();
+        let entry = pathbuf.as_path().join(ENTRY);
+        match Entry::get(entry.clone()).await {
+            Ok(_) => (),
+            Err(_) => {
+                let store = DataType::new("store").unwrap();
+                match Entry::new(entry, store).await {
+                    Ok(_) => (),
+                    Err(err) => {
+                        let mut error = DBError::from_code(ErrorCode::CacheReadWrite);
+                        error.add_source(err);
+                        return Err(error);
+                    }
+                }
+            }
+        }
+        Ok(Self {
+            next_id: fn id() -> String { thread_rng().sample_iter(&Alphanumeric).take(64).collect() },
+            session: [ENTRY.to_string()].to_vec(),
+        })
+    }
+
+    fn set_session(&mut self, sess: Vec<String>) {
+        self.session = sess;
+    }
+
+    async fn new_entry(&self, _name: &str) -> Self {
+        self.clone()
+    }
+}
+
+#[cfg(test)]
+mod datatype {
+    use super::*;
+
+    #[test]
+    fn bad_data_type() -> Result<(), DBError> {
+        let dt = "bufcuss";
+        match DataType::new(dt) {
+            Ok(_) => Err(DBError::new("should have produced an error")),
+            Err(err) => match err.code {
+                ErrorCode::DataTypeIncorrect(value) => {
+                    assert_eq!(value, dt, "Incorrect input value");
+                    Ok(())
+                }
+                _ => {
+                    let mut error = DBError::new("incorrect error");
+                    error.add_source(err);
+                    Err(error)
+                }
+            },
+        }
+    }
+
+    #[test]
+    fn create_store() -> Result<(), DBError> {
+        match DataType::new("store") {
+            Ok(dt) => match dt {
+                DataType::DBMap(_) => Ok(()),
+                _ => Err(DBError::new("incorrect data type")),
+            },
+            Err(err) => Err(err),
+        }
+    }
+
+    #[test]
+    fn create_database() -> Result<(), DBError> {
+        match DataType::new("database") {
+            Ok(dt) => match dt {
+                DataType::TableMap(_) => Ok(()),
+                _ => Err(DBError::new("incorrect data type")),
+            },
+            Err(err) => Err(err),
+        }
+    }
+}
+
+#[cfg(test)]
+mod datatype_sesssion {
+    use super::*;
+
+    #[test]
+    fn update_storage() {
+        let mut dbs = DataType::new("store").unwrap();
+        let name = "new_database";
+        let id = "someid";
+        dbs.add("database", name, id).unwrap();
+        assert_eq!(dbs.eq("database", name).unwrap(), [id].to_vec());
+        assert_eq!(dbs.list(["database"].to_vec()).unwrap(), [name].to_vec());
+    }
+}
+
+#[cfg(test)]
+mod datatype_file {
+    use super::*;
+
+    #[test]
+    fn new_store_bytes() {
+        let dbs = DataType::new("store").unwrap();
+        let mut expected = "DBMap".as_bytes().to_vec();
+        expected.push(0);
+        assert_eq!(dbs.to_bytes(), expected);
+    }
+
+    #[test]
+    fn store_bytes_with_info() {
+        let name = "title";
+        let id = "king";
+        let mut store = Store::new();
+        let mut dt_store = DataType::new("store").unwrap();
+        let mut expected = dt_store.to_bytes();
+        store.add("database", name, id).unwrap();
+        expected.append(&mut store.to_bytes());
+        dt_store.add("database", name, id).unwrap();
+        assert_eq!(dt_store.to_bytes(), expected);
+    }
+
+    #[test]
+    fn read_empty_store() {
+        let dt_store = DataType::new("store").unwrap();
+        let data = dt_store.to_bytes();
+        let mut feed = data.iter();
+        let output = DataType::from_bytes(&mut feed).unwrap();
+        assert_eq!(
+            dt_store.list(["database"].to_vec()).unwrap(),
+            output.list(["database"].to_vec()).unwrap()
+        );
+    }
+
+    #[test]
+    fn read_store_info() {
+        let mut dt_store = DataType::new("store").unwrap();
+        dt_store.add("database", "raven", "beastboy").unwrap();
+        let data = dt_store.to_bytes();
+        let mut feed = data.iter();
+        let output = DataType::from_bytes(&mut feed).unwrap();
+        assert_eq!(
+            dt_store.list(["database"].to_vec()).unwrap(),
+            output.list(["database"].to_vec()).unwrap()
+        );
+    }
+
+    #[test]
+    fn new_database_bytes() {
+        let db = DataType::new("database").unwrap();
+        let mut expected = "TableMap".as_bytes().to_vec();
+        expected.push(0);
+        assert_eq!(db.to_bytes(), expected);
+    }
+
+    #[test]
+    fn read_empty_database() {
+        let dt = DataType::new("database").unwrap();
+        let data = dt.to_bytes();
+        let mut feed = data.iter();
+        match DataType::from_bytes(&mut feed).unwrap() {
+            DataType::TableMap(_) => (),
+            _ => assert!(false, "Incorrect data type"),
+        }
+    }
+
+    #[test]
+    fn read_bad_header() -> Result<(), DBError> {
+        let data = "sdghsdl".as_bytes().to_vec();
+        let mut feed = data.iter();
+        match DataType::from_bytes(&mut feed) {
+            Ok(_) => Err(DBError::new("should have raised an error")),
+            Err(err) => match err.code {
+                ErrorCode::CorruptFile => Ok(()),
+                _ => Err(DBError::new("incorrect error")),
+            },
+        }
+    }
+
+    #[test]
+    fn read_bad_store() -> Result<(), DBError> {
+        let mut data = "DBMap".as_bytes().to_vec();
+        data.push(0);
+        data.append(&mut "sdfgs".as_bytes().to_vec());
+        let mut feed = data.iter();
+        match DataType::from_bytes(&mut feed) {
+            Ok(_) => Err(DBError::new("should have raised an error")),
+            Err(err) => match err.code {
+                ErrorCode::CorruptFile => Ok(()),
+                _ => Err(DBError::new("incorrect error code")),
+            },
+        }
+    }
+}
+
+#[cfg(test)]
+mod db {
+    use super::*;
+    use async_std::fs::write;
+    use std::error::Error;
+    use tempfile::tempdir;
+
+    #[async_std::test]
+    async fn create() {
+        let dir = tempdir().unwrap();
+        let mtt = MoreThanText::new(dir.path()).await.unwrap();
+        let epoint = dir.path().join(ENTRY);
+        assert!(
+            epoint.is_file(),
+            "{} did not get created.",
+            epoint.display()
+        );
+        let entry = Entry::get(epoint.to_str().unwrap()).await.unwrap();
+        assert_eq!(
+            entry.data().list(["database"].to_vec()).unwrap(),
+            Vec::<String>::new()
+        );
+        let sess = [ENTRY];
+        assert_eq!(mtt.session, sess);
+    }
+
+    #[async_std::test]
+    async fn entry_failure() -> Result<(), DBError> {
+        let dir = tempdir().unwrap();
+        let path = dir.path().join("bad").join("path");
+        match MoreThanText::new(path).await {
+            Ok(_) => Err(DBError::new("Should have produced an error.")),
+            Err(err) => match err.code {
+                ErrorCode::CacheReadWrite => {
+                    assert!(err.source().is_some(), "Error should have a source.");
+                    assert!(
+                        err.source().unwrap().to_string().contains("write failure"),
+                        "Source Error Message: {}",
+                        err.source().unwrap().to_string()
+                    );
+                    Ok(())
+                }
+                _ => Err(DBError::new("incorrect error code")),
+            },
+        }
+    }
+
+    #[async_std::test]
+    async fn existing_entry_point() -> Result<(), DBError> {
+        let dir = tempdir().unwrap();
+        let data = DataType::new("store").unwrap();
+        Entry::new(dir.path().join(ENTRY), data.clone())
+            .await
+            .unwrap();
+        match MoreThanText::new(dir.path()).await {
+            Ok(_) => Ok(()),
+            Err(err) => Err(err),
+        }
+    }
+
+    #[async_std::test]
+    async fn corrupt_enty_point() -> Result<(), DBError> {
+        let dir = tempdir().unwrap();
+        let file = dir.path().join(ENTRY);
+        write(file, b"Really bad data.").await.unwrap();
+        match MoreThanText::new(dir.path()).await {
+            Ok(_) => Err(DBError::new("should have errored")),
+            Err(_) => Ok(()),
+        }
+    }
+
+    #[async_std::test]
+    async fn set_session() {
+        let dir = tempdir().unwrap();
+        let mut mtt = MoreThanText::new(dir.path()).await.unwrap();
+        let sess = ["different".to_string()];
+        mtt.set_session(sess.to_vec());
+        assert_eq!(mtt.session, sess);
+    }
+
+    #[async_std::test]
+    async fn add_a_database() {
+        let dir = tempdir().unwrap();
+        let mtt = MoreThanText::new(dir.path()).await.unwrap();
+        mtt.new_entry("wilbur").await;
+    }
+}

src/morethantext/mod-3.rs

@@ -0,0 +1,640 @@
+use async_std::{
+    channel::{unbounded, Receiver, Sender},
+    path::PathBuf,
+    task::spawn,
+};
+use std::{collections::HashMap, error::Error, fmt};
+
+const ENTRY: &str = "EntryPoint";
+
+#[derive(Debug)]
+enum ErrorCode {
+    // General
+    Undefined(String),
+    // Cache
+    EntryNotFound(String),
+    InvalidCommitData,
+    // Store
+    DatabaseAlreadyExists(String),
+}
+
+impl fmt::Display for ErrorCode {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            ErrorCode::Undefined(msg) => write!(f, "{}", msg),
+            ErrorCode::EntryNotFound(id) => write!(f, "entry '{}' was not found", id),
+            ErrorCode::InvalidCommitData => write!(f, "commit data was not a database store"),
+            ErrorCode::DatabaseAlreadyExists(name) => {
+                write!(f, "database '{}' already exists", name)
+            }
+        }
+    }
+}
+
+mod errorcodes {
+    use super::*;
+
+    const ITEMS: [&str; 2] = ["one", "two"];
+
+    #[test]
+    fn undefined_display() {
+        for item in ITEMS {
+            let err = ErrorCode::Undefined(item.to_string());
+            assert_eq!(err.to_string(), item);
+        }
+    }
+
+    #[test]
+    fn bad_entry() {
+        for item in ITEMS {
+            let err = ErrorCode::EntryNotFound(item.to_string());
+            assert_eq!(err.to_string(), format!("entry '{}' was not found", item));
+        }
+    }
+
+    #[test]
+    fn invalid_commit_data() {
+        let err = ErrorCode::InvalidCommitData;
+        assert_eq!(err.to_string(), "commit data was not a database store");
+    }
+
+    #[test]
+    fn database_already_exists() {
+        for item in ITEMS {
+            let err = ErrorCode::DatabaseAlreadyExists(item.to_string());
+            assert_eq!(
+                err.to_string(),
+                format!("database '{}' already exists", item)
+            );
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct MTTError {
+    code: ErrorCode,
+}
+
+impl MTTError {
+    fn new<S>(msg: S) -> Self
+    where
+        S: Into<String>,
+    {
+        let text = msg.into();
+        Self {
+            code: ErrorCode::Undefined(text),
+        }
+    }
+
+    fn from_code(code: ErrorCode) -> Self {
+        Self { code: code }
+    }
+}
+
+impl Error for MTTError {}
+
+impl fmt::Display for MTTError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.code)
+    }
+}
+
+#[cfg(test)]
+mod errors {
+    use super::*;
+
+    #[test]
+    fn create_with_str() {
+        let msgs = ["one", "two"];
+        for msg in msgs {
+            let err = MTTError::new(msg);
+            assert_eq!(err.to_string(), msg);
+        }
+    }
+
+    #[test]
+    fn create_with_string() {
+        let msg = "three";
+        let err = MTTError::new(msg.to_string());
+        assert_eq!(err.to_string(), msg);
+    }
+
+    #[test]
+    fn create_from_code() {
+        let code = ErrorCode::Undefined("oops".to_string());
+        let err = MTTError::from_code(code);
+        match err.code {
+            ErrorCode::Undefined(_) => (),
+            _ => assert!(false, "{:?} is not undefined", err.code),
+        }
+    }
+
+    #[test]
+    fn create_missing_entry() {
+        let code = ErrorCode::EntryNotFound("an_id".to_string());
+        let err = MTTError::from_code(code);
+        match err.code {
+            ErrorCode::EntryNotFound(_) => (),
+            _ => assert!(false, "{:?} is not undefined", err.code),
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+struct Storage<D> {
+    id: Option<String>,
+    data: Option<D>,
+    // delete: bool,
+}
+
+impl Storage<D> {
+    fn from_id<S>(id: S) -> Self
+    where
+        S: Into<String>,
+    {
+        Self {
+            id: Some(id.into()),
+            data: None,
+        }
+    }
+
+    fn from_datatype(dt: DataType) -> Self {
+        Self {
+            id: None,
+            data: Some(dt),
+        }
+    }
+}
+
+#[cfg(test)]
+mod storage {
+    use super::*;
+
+    #[test]
+    fn from_id_with_str() {
+        let ids = ["first", "second"];
+        for id in ids {
+            let output = Storage::from_id(id);
+            assert_eq!(output.id, Some(id.to_string()));
+            assert!(
+                output.data.is_none(),
+                "The storage data should have been Non."
+            );
+        }
+    }
+
+    #[test]
+    fn from_id_with_string() {
+        let id = "my_id".to_string();
+        let output = Storage::from_id(id.clone());
+        assert_eq!(output.id, Some(id));
+    }
+
+    #[test]
+    fn from_store() {
+        let output = Storage::from_datatype(DataType::new("store"));
+        assert!(output.id.is_none(), "id should be None.");
+        assert!(output.data.is_some(), "There should be data");
+        let result = output.data.unwrap();
+        match result {
+            DataType::DBMap(_) => (),
+            _ => assert!(false, "{:?} should have been DataType::DBMap.", result),
+        }
+    }
+
+    #[test]
+    fn from_database() {
+        let output = Storage::from_datatype(DataType::new("database"));
+        let result = output.data.unwrap();
+        match result {
+            DataType::TableMap(_) => (),
+            _ => assert!(false, "{:?} should have been DataType::TableMap.", result),
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+struct Store {
+    data: HashMap<String, Storage<Database>>,
+}
+
+impl Store {
+    fn new() -> Self {
+        Self {
+            data: HashMap::new(),
+        }
+    }
+
+    fn add_new<S>(&mut self, name: S) -> Result<(), MTTError>
+    where
+        S: Into<String>,
+    {
+        let dbname = name.into();
+        match self.get(&dbname) {
+            Some(_) => Err(MTTError::from_code(ErrorCode::DatabaseAlreadyExists(
+                dbname,
+            ))),
+            None => {
+                self.data
+                    .insert(dbname, Storage::from_datatype(DataType::new("database")));
+                Ok(())
+            }
+        }
+    }
+
+    fn get(&self, name: &str) -> Option<&Storage<Database>> {
+        self.data.get(name)
+    }
+}
+
+#[cfg(test)]
+mod stores {
+    use super::*;
+
+    #[test]
+    fn get_no_database() -> Result<(), MTTError> {
+        let store = Store::new();
+        match store.get("missing_name") {
+            Some(_) => Err(MTTError::new("should have returned None")),
+            None => Ok(()),
+        }
+    }
+
+    #[test]
+    fn add_database_str() {
+        let mut store = Store::new();
+        let names = ["first", "second"];
+        for name in names {
+            store.add_new(name).unwrap();
+            let output = store.get(name).unwrap();
+            assert!(output.data.is_some(), "There should be a data type.");
+            match output.data.clone().unwrap() {
+                DataType::TableMap(_) => (),
+                _ => assert!(
+                    false,
+                    "{:?} should have been DataType::TableMap.",
+                    output.data
+                ),
+            }
+            assert!(output.id.is_none(), "Should not have an id.");
+        }
+    }
+
+    #[test]
+    fn add_database_string() {
+        let mut store = Store::new();
+        let name = "third".to_string();
+        store.add_new(name.clone()).unwrap();
+        let output = store.get(&name).unwrap();
+        match output.data.clone().unwrap() {
+            DataType::TableMap(_) => (),
+            _ => assert!(
+                false,
+                "{:?} should have been DataType::TableMap.",
+                output.data
+            ),
+        }
+    }
+
+    #[test]
+    fn no_duplicate_database_names() -> Result<(), MTTError> {
+        let mut store = Store::new();
+        let name = "duplicate";
+        store.add_new(name).unwrap();
+        match store.add_new(name) {
+            Ok(_) => Err(MTTError::new("should have been an error")),
+            Err(err) => match err.code {
+                ErrorCode::DatabaseAlreadyExists(dbname) => {
+                    assert_eq!(dbname, name);
+                    Ok(())
+                }
+                _ => Err(MTTError::new(format!(
+                    "{:?} should have been DatabaseAlreadyExists.",
+                    err.code
+                ))),
+            },
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+struct Database;
+
+#[cfg(test)]
+mod databases {
+    use super::*;
+
+    #[test]
+    fn create() {
+        Database::new();
+    }
+}
+
+impl Database {
+    fn new() -> Self {
+        Self {}
+    }
+}
+
+#[derive(Clone, Debug)]
+enum DataType {
+    DBMap(Store),
+    TableMap(Database),
+}
+
+impl DataType {
+    fn new(dtype: &str) -> DataType {
+        match dtype {
+            "store" => Self::DBMap(Store::new()),
+            "database" => Self::TableMap(Database::new()),
+            _ => unreachable!(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod datatypes {
+    use super::*;
+
+    #[test]
+    fn create_store() {
+        let dtype = DataType::new("store");
+        match dtype {
+            DataType::DBMap(_) => (),
+            _ => assert!(false, "{:?} is not incorrect data type", dtype),
+        }
+    }
+
+    #[test]
+    fn create_database() {
+        let dtype = DataType::new("database");
+        match dtype {
+            DataType::TableMap(_) => (),
+            _ => assert!(false, "{:?} is not incorrect data type", dtype),
+        }
+    }
+}
+
+#[derive(Debug)]
+enum FromCache {
+    Ok,
+    Data(HashMap<String, DataType>),
+    Error(MTTError),
+}
+
+struct CacheQuery {
+    ids: Vec<String>,
+    reply: Sender<FromCache>,
+}
+
+struct CacheCommit {
+    reply: Sender<FromCache>,
+    data: DataType,
+}
+
+impl CacheCommit {
+    fn new(data: DataType, channel: Sender<FromCache>) -> Result<Self, MTTError> {
+        match data {
+            DataType::DBMap(_) => (),
+            _ => return Err(MTTError::from_code(ErrorCode::InvalidCommitData)),
+        }
+        Ok(Self {
+            data: data,
+            reply: channel,
+        })
+    }
+}
+
+mod commits {
+    use super::*;
+
+    #[test]
+    fn create() -> Result<(), MTTError> {
+        let (s, _) = unbounded();
+        match CacheCommit::new(DataType::new("store"), s) {
+            Ok(output) => match output.data {
+                DataType::DBMap(_) => Ok(()),
+                _ => Err(MTTError::new(format!(
+                    "{:?} should have been DBMap",
+                    output.data
+                ))),
+            },
+            Err(err) => Err(err),
+        }
+    }
+
+    #[test]
+    fn bad_data_type() -> Result<(), MTTError> {
+        let (s, _) = unbounded();
+        match CacheCommit::new(DataType::new("database"), s) {
+            Ok(_) => Err(MTTError::new("CacheCommit::new did not return error")),
+            Err(err) => match err.code {
+                ErrorCode::InvalidCommitData => Ok(()),
+                _ => Err(MTTError::new(format!(
+                    "{:?} is not the correct error",
+                    err.code
+                ))),
+            },
+        }
+    }
+}
+
+enum ToCache {
+    Query(CacheQuery),
+    Commit(CacheCommit),
+}
+
+#[derive(Clone)]
+pub struct MoreThanText {
+    session: Vec<String>,
+    cache: Sender<Vec<String>>,
+}
+
+impl MoreThanText {
+    async fn new(cache: Sender<Vec<String>>) -> Result<Self, MTTError> {
+        Ok(Self {
+            session: [ENTRY.to_string()].to_vec(),
+            cache: cache,
+        })
+    }
+}
+
+#[cfg(test)]
+mod mtt {
+    use super::*;
+
+    #[async_std::test]
+    async fn create() {
+        let (s, _) = unbounded();
+        let mtt = MoreThanText::new(s).await.unwrap();
+        assert_eq!(mtt.session, [ENTRY]);
+    }
+}
+
+struct Cache;
+
+impl Cache {
+    async fn new<P>(_dir: P) -> Result<Self, MTTError>
+    where
+        P: Into<PathBuf>,
+    {
+        Ok(Self {})
+    }
+
+    async fn query(&self, qry: &Vec<String>) -> Result<HashMap<String, DataType>, MTTError> {
+        let mut output = HashMap::new();
+        for id in qry {
+            if id == ENTRY {
+                output.insert(ENTRY.to_string(), DataType::new("store"));
+            } else {
+                return Err(MTTError::from_code(ErrorCode::EntryNotFound(
+                    id.to_string(),
+                )));
+            }
+        }
+        Ok(output)
+    }
+
+    async fn commit(&self) -> Result<(), MTTError> {
+        Ok(())
+    }
+
+    async fn start(&self, listener: Receiver<ToCache>) {
+        loop {
+            match listener.recv().await.unwrap() {
+                ToCache::Query(qry) => match self.query(&qry.ids).await {
+                    Ok(data) => qry.reply.send(FromCache::Data(data)).await.unwrap(),
+                    Err(error) => qry.reply.send(FromCache::Error(error)).await.unwrap(),
+                },
+                ToCache::Commit(commit) => match self.commit().await {
+                    Ok(_) => commit.reply.send(FromCache::Ok).await.unwrap(),
+                    Err(error) => commit.reply.send(FromCache::Error(error)).await.unwrap(),
+                },
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod caches {
+    use super::*;
+    use tempfile::tempdir;
+
+    async fn start_cache<P>(dir: P) -> Sender<ToCache>
+    where
+        P: Into<PathBuf>,
+    {
+        let (s, r) = unbounded();
+        let datadir = dir.into();
+        spawn(async move {
+            let cache = Cache::new(datadir).await.unwrap();
+            cache.start(r).await;
+        });
+        s
+    }
+
+    async fn send_request(data: Vec<&str>, channel: Sender<ToCache>) -> FromCache {
+        let mut ids = Vec::new();
+        for id in data.iter() {
+            ids.push(id.to_string());
+        }
+        let (s, r) = unbounded();
+        let msg = ToCache::Query(CacheQuery { ids: ids, reply: s });
+        channel.send(msg).await.unwrap();
+        r.recv().await.unwrap()
+    }
+
+    #[async_std::test]
+    async fn create() {
+        let dir = tempdir().unwrap();
+        let s_cache = start_cache(dir.path()).await;
+        let result = send_request(vec![ENTRY], s_cache).await;
+        match result {
+            FromCache::Data(data) => match data.get(ENTRY) {
+                Some(output) => match output {
+                    DataType::DBMap(_) => (),
+                    _ => assert!(false, "{:?} is not a database store.", output),
+                },
+                None => assert!(false, "Should contain entry point."),
+            },
+            _ => assert!(false, "{:?} should have been a store.", result),
+        }
+    }
+
+    #[async_std::test]
+    async fn bad_entry() {
+        let dir = tempdir().unwrap();
+        let s_cache = start_cache(dir.path()).await;
+        let result = send_request(vec!["bad_id"], s_cache).await;
+        match result {
+            FromCache::Error(_) => (),
+            _ => assert!(false, "{:?} should have been an error.", result),
+        }
+    }
+
+    #[async_std::test]
+    async fn empty_commit() {
+        let dir = tempdir().unwrap();
+        let s_cache = start_cache(dir.path()).await;
+        let (s, r) = unbounded();
+        let msg = ToCache::Commit(CacheCommit::new(DataType::new("store"), s).unwrap());
+        s_cache.send(msg).await.unwrap();
+        let result = r.recv().await.unwrap();
+        match result {
+            FromCache::Ok => (),
+            _ => assert!(false, "{:?} should have been an Ok.", result),
+        }
+    }
+
+    #[async_std::test]
+    async fn get_store() {
+        let dir = tempdir().unwrap();
+        let cache = Cache::new(dir.path()).await.unwrap();
+        let output = cache.query(&[ENTRY.to_string()].to_vec()).await.unwrap();
+        let result = output.get(ENTRY).unwrap();
+        match result {
+            DataType::DBMap(_) => (),
+            _ => assert!(false, "{:?} should have been an Ok.", result),
+        }
+    }
+
+    #[async_std::test]
+    async fn bad_get() {
+        let dir = tempdir().unwrap();
+        let cache = Cache::new(dir.path()).await.unwrap();
+        let bad_id = "really_bad_id";
+        match cache.query(&[bad_id.to_string()].to_vec()).await {
+            Ok(_) => assert!(false, "Should have produced an error."),
+            Err(err) => match err.code {
+                ErrorCode::EntryNotFound(id) => assert_eq!(id, bad_id),
+                _ => assert!(false, "{:?} should have been EntryNotFound.", err.code),
+            },
+        }
+    }
+}
+
+pub async fn start_db<P>(_dir: P) -> Result<MoreThanText, MTTError>
+where
+    P: Into<PathBuf>,
+{
+    let (s, r) = unbounded();
+    spawn(async move {
+        loop {
+            r.recv().await.unwrap();
+        }
+    });
+    Ok(MoreThanText::new(s).await.unwrap())
+}
+
+#[cfg(test)]
+mod db_start_up {
+    use super::*;
+    use tempfile::tempdir;
+
+    #[async_std::test]
+    async fn initial_session() {
+        let dir = tempdir().unwrap();
+        let mtt = start_db(dir.path()).await.unwrap();
+        assert_eq!(mtt.session, [ENTRY]);
+    }
+}

src/morethantext/mod-old.rs

@@ -0,0 +1,823 @@
+mod cache;
+mod database;
+pub mod error;
+mod store;
+
+use async_std::{
+    fs::{create_dir, read, remove_file, write},
+    path::Path,
+    sync::{Arc, Mutex},
+    task::{sleep, spawn},
+};
+use database::Database;
+use error::{DBError, ErrorCode};
+use rand::{distributions::Alphanumeric, thread_rng, Rng};
+use std::{
+    collections::HashMap,
+    fmt, slice, str,
+    time::{Duration, Instant},
+};
+use store::Store;
+
+const DATA: &str = "data";
+const ENTRY: &str = "databases";
+
+trait FileData<F> {
+    fn to_bytes(&self) -> Vec<u8>;
+    fn from_bytes(data: &mut slice::Iter<u8>) -> Result<F, DBError>;
+}
+
+trait SessionData {
+    fn add(&mut self, key: &str, value: &str, data: &str) -> Result<Vec<String>, DBError>;
+    fn eq(&self, key: &str, value: &str) -> Result<Vec<String>, DBError>;
+    fn list(&self, keys: Vec<&str>) -> Result<Vec<String>, DBError>;
+}
+
+#[derive(Clone)]
+pub enum CacheType {
+    Raw(String),
+    DBMap(Store),
+    TableMap,
+}
+
+impl CacheType {
+    pub fn entry_type(&self) -> String {
+        match self {
+            CacheType::Raw(_) => "Raw".to_string(),
+            CacheType::DBMap(_) => "DBMap".to_string(),
+            CacheType::TableMap => "TableMap".to_string(),
+        }
+    }
+
+    pub fn to_bytes(&self) -> Vec<u8> {
+        let mut output = self.entry_type().into_bytes();
+        output.push(0);
+        match self {
+            CacheType::Raw(s) => output.append(&mut s.as_bytes().to_vec()),
+            CacheType::DBMap(_) => (),
+            CacheType::TableMap => (),
+        }
+        return output;
+    }
+
+    pub fn from_bytes(data: Vec<u8>) -> Result<CacheType, DBError> {
+        let mut data_iter = data.iter();
+        let mut letter: u8;
+        match data_iter.next() {
+            Some(item) => letter = *item,
+            None => return Err(DBError::new("empty file")),
+        }
+        let mut header: Vec<u8> = Vec::new();
+        while letter != 0 {
+            header.push(letter.clone());
+            match data_iter.next() {
+                Some(item) => letter = *item,
+                None => return Err(DBError::new("incomplete file")),
+            }
+        }
+        let header = str::from_utf8(&header).unwrap().to_string();
+        match header.as_str() {
+            "Raw" => {
+                let mut output: Vec<u8> = Vec::new();
+                for letter in data_iter {
+                    output.push(letter.clone());
+                }
+                Ok(CacheType::Raw(str::from_utf8(&output).unwrap().to_string()))
+            }
+            "DBMap" => Ok(CacheType::DBMap(Store::new())),
+            "TableMap" => Ok(CacheType::TableMap),
+            _ => Err(DBError::new("data corruption")),
+        }
+    }
+}
+
+impl fmt::Display for CacheType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            CacheType::Raw(s) => write!(f, "{}", s),
+            CacheType::DBMap(_) => todo!(),
+            CacheType::TableMap => todo!(),
+        }
+    }
+}
+
+#[derive(Clone)]
+struct CacheEntry {
+    data: CacheType,
+    last_used: Instant,
+}
+
+impl CacheEntry {
+    fn new(data: CacheType) -> Self {
+        Self {
+            data: data,
+            last_used: Instant::now(),
+        }
+    }
+
+    fn elapsed(&self) -> Duration {
+        self.last_used.elapsed()
+    }
+
+    fn touch(&mut self) {
+        self.last_used = Instant::now();
+    }
+
+    fn update(&mut self, data: CacheType) {
+        self.data = data;
+        self.touch();
+    }
+}
+
+impl fmt::Display for CacheEntry {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.data)
+    }
+}
+
+#[derive(Clone)]
+pub struct MoreThanText {
+    cache: Arc<Mutex<HashMap<String, CacheEntry>>>,
+    dir: String,
+    session: Vec<String>,
+}
+
+impl MoreThanText {
+    pub async fn new(dir: &str) -> Result<Self, DBError> {
+        let data_dir = Path::new(dir).join(DATA);
+        if !data_dir.is_dir().await {
+            match create_dir(&data_dir).await {
+                Ok(_) => (),
+                Err(err) => {
+                    let mut error = DBError::new("failed to create data directory");
+                    error.add_source(err);
+                    return Err(error);
+                }
+            }
+        }
+        let mut output = Self {
+            cache: Arc::new(Mutex::new(HashMap::new())),
+            dir: data_dir.to_str().unwrap().to_string(),
+            session: Vec::new(),
+        };
+        let entry_file = Path::new(dir).join(ENTRY);
+        let id: String;
+        if entry_file.is_file().await {
+            let holder = read(entry_file).await.unwrap();
+            id = str::from_utf8(&holder).unwrap().to_string();
+        } else {
+            id = output
+                .add_entry(CacheType::DBMap(Store::new()))
+                .await
+                .unwrap();
+            write(entry_file, id.as_bytes()).await.unwrap();
+        }
+        output.session.push(id);
+        let looper = output.cache.clone();
+        spawn(async move {
+            let hold_time = Duration::from_secs(300);
+            loop {
+                sleep(Duration::from_secs(1)).await;
+                let mut ids: Vec<String> = Vec::new();
+                let mut cache = looper.lock().await;
+                for (id, entry) in cache.iter() {
+                    if entry.elapsed() > hold_time {
+                        ids.push(id.to_string());
+                    }
+                }
+                for id in ids.iter() {
+                    cache.remove(id);
+                }
+            }
+        });
+        Ok(output)
+    }
+
+    fn filename(&self, id: &str) -> String {
+        let filename = Path::new(&self.dir).join(&id);
+        filename.into_os_string().into_string().unwrap()
+    }
+
+    fn new_id(&self) -> String {
+        thread_rng().sample_iter(&Alphanumeric).take(64).collect()
+    }
+
+    async fn add(&self, feature: &str, key: &str, value: &str) -> Self {
+        let mut ids: Vec<String> = Vec::new();
+        for id in self.session.clone().into_iter() {
+            let holder = self.get_entry(&id).await.unwrap();
+            //holder.add(feature, key, value);
+        }
+        let mut output = self.clone();
+        output.session.clear();
+        output.session.push(value.to_string());
+        output
+    }
+
+    async fn list(&self, feature: Vec<&str>) -> Result<Vec<String>, DBError> {
+        Ok(Vec::new())
+    }
+
+    async fn add_entry(&self, entry: CacheType) -> Result<String, DBError> {
+        let mut id: String = "".to_string();
+        let mut dup = true;
+        while dup {
+            id = thread_rng().sample_iter(&Alphanumeric).take(32).collect();
+            dup = Path::new(&self.dir).join(&id).as_path().exists().await;
+        }
+        match write(Path::new(&self.filename(&id)), entry.to_bytes()).await {
+            Ok(_) => (),
+            Err(err) => {
+                let mut error = DBError::new("data write");
+                error.add_source(err);
+                return Err(error);
+            }
+        };
+        let mut cache = self.cache.lock().await;
+        let data = CacheEntry::new(entry);
+        cache.insert(id.clone(), data);
+        Ok(id)
+    }
+
+    async fn get_entry(&self, id: &str) -> Result<CacheEntry, DBError> {
+        let mut cache = self.cache.lock().await;
+        match cache.get_mut(id) {
+            Some(entry) => {
+                entry.touch();
+                Ok(entry.clone())
+            }
+            None => match read(Path::new(&self.filename(id))).await {
+                Ok(content) => {
+                    let data = CacheEntry::new(CacheType::from_bytes(content).unwrap());
+                    cache.insert(id.to_string(), data.clone());
+                    Ok(data)
+                }
+                Err(_) => Err(DBError::new("cache entry not found")),
+            },
+        }
+    }
+
+    async fn update_entry(&self, id: &str, entry: CacheType) -> Result<(), DBError> {
+        match self.get_entry(id).await {
+            Ok(_) => (),
+            Err(err) => return Err(err),
+        }
+        match write(Path::new(&self.filename(id)), entry.to_bytes()).await {
+            Ok(_) => (),
+            Err(err) => {
+                let mut error = DBError::new("data write");
+                error.add_source(err);
+                return Err(error);
+            }
+        }
+        let mut cache = self.cache.lock().await;
+        let data = CacheEntry::new(entry);
+        cache.insert(id.to_string(), data);
+        Ok(())
+    }
+
+    async fn delete_entry(&self, id: &str) -> Result<(), DBError> {
+        let mut cache = self.cache.lock().await;
+        cache.remove(id);
+        match remove_file(Path::new(&self.filename(id))).await {
+            Ok(_) => Ok(()),
+            Err(err) => {
+                let mut error = DBError::new("data delete");
+                error.add_source(err);
+                Err(error)
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod setup {
+    use super::*;
+    use async_std::fs::remove_dir_all;
+    use tempfile::{tempdir, TempDir};
+
+    pub struct MTT {
+        pub db: MoreThanText,
+        pub dir: TempDir,
+    }
+
+    impl MTT {
+        pub async fn new() -> Self {
+            let dir = tempdir().unwrap();
+            let db = MoreThanText::new(dir.path().to_str().unwrap())
+                .await
+                .unwrap();
+            Self { db: db, dir: dir }
+        }
+
+        pub async fn create_io_error(&self) {
+            remove_dir_all(self.dir.path().join(DATA)).await.unwrap();
+        }
+    }
+}
+
+#[cfg(test)]
+mod init {
+    use super::*;
+    use std::error::Error;
+    use tempfile::tempdir;
+
+    #[async_std::test]
+    async fn create_data_dir() {
+        let dir = tempdir().unwrap();
+        MoreThanText::new(dir.path().to_str().unwrap())
+            .await
+            .unwrap();
+        let data_dir = dir.path().join(DATA);
+        assert!(data_dir.is_dir(), "Did not create the data directory.");
+        dir.close().unwrap();
+    }
+
+    #[async_std::test]
+    async fn existing_data_dir() {
+        let dir = tempdir().unwrap();
+        let data_dir = dir.path().join(DATA);
+        create_dir(data_dir).await.unwrap();
+        MoreThanText::new(dir.path().to_str().unwrap())
+            .await
+            .unwrap();
+        dir.close().unwrap();
+    }
+
+    #[async_std::test]
+    async fn bad_data_dir() {
+        let msg = "could not create directory";
+        match MoreThanText::new("kljsdgfhslkfrh").await {
+            Ok(_) => assert!(false, "This test should fail to create a data directory"),
+            Err(err) => {
+                assert_eq!(err.to_string(), "failed to create data directory");
+                assert!(err.source().is_some(), "Must include the source error.");
+                let err_msg = err.source().unwrap().to_string();
+                assert!(err_msg.contains(msg), "'{}' not in '{}'", msg, err_msg);
+            }
+        };
+    }
+
+    #[async_std::test]
+    async fn creates_entry_point() {
+        let dir = tempdir().unwrap();
+        let db = MoreThanText::new(dir.path().to_str().unwrap())
+            .await
+            .unwrap();
+        let entry = dir.path().join(ENTRY);
+        assert!(entry.is_file(), "Did not create entry point file.");
+        let data = read(entry).await.unwrap();
+        let id = str::from_utf8(&data).unwrap();
+        let cache = db.get_entry(&id).await.unwrap();
+        assert_eq!(cache.data.entry_type(), "DBMap");
+        assert_eq!(db.session, [id]);
+    }
+
+    #[async_std::test]
+    async fn use_existing_entry_point() {
+        let dir = tempdir().unwrap();
+        let db1 = MoreThanText::new(dir.path().to_str().unwrap())
+            .await
+            .unwrap();
+        let db2 = MoreThanText::new(dir.path().to_str().unwrap())
+            .await
+            .unwrap();
+        assert_eq!(db1.session, db2.session, "Did not read existing entry.");
+    }
+}
+
+#[cfg(test)]
+mod data {
+    use super::*;
+    use setup::MTT;
+
+    #[async_std::test]
+    async fn ids_are_random() {
+        let mtt = MTT::new().await;
+        let id1 = mtt.db.new_id();
+        let id2 = mtt.db.new_id();
+        assert_ne!(id1, id2, "Ids should be random");
+    }
+
+    #[async_std::test]
+    async fn add_database() {
+        let mtt = MTT::new().await;
+        let name = "fred";
+        let id = "*gsdfg";
+        let output = mtt.db.add("database", name, id).await;
+        assert_eq!(output.session, [id], "should update session info.");
+        /*
+        assert_eq!(
+            mtt.db.list(["database"].to_vec()).await.unwrap(),
+            [name],
+            "Should list the databases."
+        );
+        */
+    }
+}
+
+#[cfg(test)]
+mod cache_test {
+    use super::*;
+    use async_std::fs::read;
+    use setup::MTT;
+    use std::error::Error;
+
+    #[async_std::test]
+    async fn entry_ids_are_random() {
+        let mtt = MTT::new().await;
+        let data1 = CacheType::Raw("one".to_string());
+        let data2 = CacheType::Raw("two".to_string());
+        let id1 = mtt.db.add_entry(data1).await.unwrap();
+        let id2 = mtt.db.add_entry(data2).await.unwrap();
+        assert_ne!(id1, id2, "Ids should be unique.")
+    }
+
+    #[async_std::test]
+    async fn store_cache() {
+        let mtt = MTT::new().await;
+        let data = "something";
+        let expected = CacheType::Raw(data.to_string());
+        let id = mtt.db.add_entry(expected.clone()).await.unwrap();
+        let output = mtt.db.get_entry(&id).await.unwrap();
+        assert_eq!(output.to_string(), data);
+        let dfile = mtt.dir.path().join(DATA).join(&id);
+        assert!(dfile.is_file(), "Cache file should exist.");
+        let content = read(dfile).await.unwrap();
+        assert_eq!(content, expected.to_bytes());
+    }
+
+    #[async_std::test]
+    async fn get_entry_uodates_time() {
+        let mtt = MTT::new().await;
+        let id = "something";
+        let holder = CacheEntry {
+            data: CacheType::Raw("old".to_string()),
+            last_used: Instant::now() - Duration::from_secs(200),
+        };
+        let mut cache = mtt.db.cache.lock().await;
+        cache.insert(id.to_string(), holder);
+        drop(cache);
+        mtt.db.get_entry(&id).await.unwrap();
+        let cache = mtt.db.cache.lock().await;
+        let entry = cache.get(id).unwrap();
+        let held = entry.elapsed();
+        assert!(
+            Duration::from_secs(1) > held,
+            "Duration was {:?}, should have been close to 0s.",
+            held
+        );
+    }
+
+    #[async_std::test]
+    async fn retrieve_from_disk() {
+        let mtt = MTT::new().await;
+        let id = "someid";
+        let data = CacheType::Raw("stored".to_string());
+        write(mtt.dir.path().join(DATA).join(id), data.to_bytes())
+            .await
+            .unwrap();
+        let output = mtt.db.get_entry(id).await.unwrap();
+        assert_eq!(output.to_string(), data.to_string());
+        let cache = mtt.db.cache.lock().await;
+        let stored = cache.get(id);
+        assert!(stored.is_some(), "Did not store entry in the cache.");
+    }
+
+    #[async_std::test]
+    async fn store_bad_file() {
+        let mtt = MTT::new().await;
+        let msg = "could not write to file";
+        mtt.create_io_error().await;
+        match mtt.db.add_entry(CacheType::Raw("fail".to_string())).await {
+            Ok(_) => assert!(false, "This test should fail."),
+            Err(err) => {
+                assert_eq!(err.to_string(), "data write");
+                assert!(err.source().is_some(), "Must include the source error.");
+                let err_msg = err.source().unwrap().to_string();
+                assert!(err_msg.contains(msg), "'{}' not in '{}'", msg, err_msg);
+            }
+        }
+    }
+
+    #[async_std::test]
+    async fn retrieve_bad_id() {
+        let mtt = MTT::new().await;
+        match mtt.db.get_entry(&"Not Valid").await {
+            Ok(_) => assert!(false, "Should have raised an error."),
+            Err(err) => assert_eq!(err.to_string(), "cache entry not found"),
+        }
+    }
+
+    #[async_std::test]
+    async fn update_cache_entry() {
+        let mtt = MTT::new().await;
+        let id = "updateable";
+        let holder = CacheEntry {
+            data: CacheType::Raw("elder".to_string()),
+            last_used: Instant::now() - Duration::from_secs(500),
+        };
+        let mut cache = mtt.db.cache.lock().await;
+        cache.insert(id.to_string(), holder);
+        drop(cache);
+        let expected = "different";
+        let expect = CacheType::Raw(expected.to_string());
+        mtt.db.update_entry(id, expect.clone()).await.unwrap();
+        let output = mtt.db.get_entry(id).await.unwrap();
+        assert_eq!(output.to_string(), expected);
+        let cache = mtt.db.cache.lock().await;
+        let entry = cache.get(id).unwrap();
+        let held = entry.elapsed();
+        assert!(
+            Duration::from_secs(1) > held,
+            "Duration was {:?}, should have been close to 0s.",
+            held
+        );
+        drop(cache);
+        let content = read(mtt.dir.path().join(DATA).join(id)).await.unwrap();
+        assert_eq!(content, expect.to_bytes());
+    }
+
+    #[async_std::test]
+    async fn update_bad_id() {
+        let mtt = MTT::new().await;
+        match mtt
+            .db
+            .update_entry("wilma", CacheType::Raw("wrong".to_string()))
+            .await
+        {
+            Ok(_) => assert!(false, "Bad id should raise an error."),
+            Err(err) => assert_eq!(err.to_string(), "cache entry not found"),
+        }
+    }
+
+    #[async_std::test]
+    async fn update_bad_file() {
+        let mtt = MTT::new().await;
+        let msg = "could not write to file";
+        let id = mtt
+            .db
+            .add_entry(CacheType::Raw("fleeting".to_string()))
+            .await
+            .unwrap();
+        mtt.create_io_error().await;
+        match mtt
+            .db
+            .update_entry(&id, CacheType::Raw("failure".to_string()))
+            .await
+        {
+            Ok(_) => assert!(false, "This should produce a write failure."),
+            Err(err) => {
+                assert_eq!(err.to_string(), "data write");
+                assert!(err.source().is_some(), "Must include the source error.");
+                let err_msg = err.source().unwrap().to_string();
+                assert!(err_msg.contains(msg), "'{}' not in '{}'", msg, err_msg);
+            }
+        }
+    }
+
+    #[async_std::test]
+    async fn remove_entry() {
+        let mtt = MTT::new().await;
+        let id = mtt
+            .db
+            .add_entry(CacheType::Raw("delete".to_string()))
+            .await
+            .unwrap();
+        mtt.db.delete_entry(&id).await.unwrap();
+        match mtt.db.get_entry(&id).await {
+            Ok(_) => assert!(false, "Entry should be removed from cache."),
+            Err(_) => (),
+        };
+    }
+
+    #[async_std::test]
+    async fn remove_missing_entry() {
+        let mtt = MTT::new().await;
+        let msg = "could not remove file";
+        match mtt.db.delete_entry("missing").await {
+            Ok(_) => assert!(false, "This should produce a write failure."),
+            Err(err) => {
+                assert_eq!(err.to_string(), "data delete");
+                assert!(err.source().is_some(), "Must include the source error.");
+                let err_msg = err.source().unwrap().to_string();
+                assert!(err_msg.contains(msg), "'{}' not in '{}'", msg, err_msg);
+            }
+        }
+    }
+
+    #[async_std::test]
+    async fn remove_older() {
+        let mtt = MTT::new().await;
+        let id = mtt
+            .db
+            .add_entry(CacheType::Raw("removed".to_string()))
+            .await
+            .unwrap();
+        let mut cache = mtt.db.cache.lock().await;
+        let entry = cache.get_mut(&id).unwrap();
+        entry.last_used = Instant::now() - Duration::from_secs(1000);
+        drop(cache);
+        sleep(Duration::from_secs(2)).await;
+        let cache = mtt.db.cache.lock().await;
+        let output = cache.get(&id);
+        assert!(output.is_none(), "The entry shoould not be in memory.");
+        drop(cache);
+        let filename = mtt.db.filename(&id);
+        let fpath = Path::new(&filename);
+        assert!(
+            fpath.is_file().await,
+            "The stored version should still exist."
+        );
+    }
+
+    #[async_std::test]
+    async fn keep_newer() {
+        let mtt = MTT::new().await;
+        let id = mtt
+            .db
+            .add_entry(CacheType::Raw("keep".to_string()))
+            .await
+            .unwrap();
+        sleep(Duration::from_secs(2)).await;
+        let cache = mtt.db.cache.lock().await;
+        let output = cache.get(&id);
+        assert!(output.is_some(), "The entry shoould be in memory.");
+    }
+}
+
+#[cfg(test)]
+mod cache_entry {
+    use super::*;
+
+    #[test]
+    fn init() {
+        let text = "new entry";
+        let holder = CacheEntry::new(CacheType::Raw(text.to_string()));
+        assert_eq!(holder.to_string(), text);
+        let held = holder.elapsed();
+        assert!(
+            Duration::from_secs(1) > held,
+            "Duration was {:?}, should have been close to 0s.",
+            held
+        );
+    }
+
+    #[test]
+    fn older() {
+        let secs = 800;
+        let holder = CacheEntry {
+            data: CacheType::Raw("older".to_string()),
+            last_used: Instant::now() - Duration::from_secs(secs),
+        };
+        let held = holder.elapsed() - Duration::from_secs(secs);
+        assert!(
+            Duration::from_secs(1) > held,
+            "{:?} should be close to {}s",
+            holder.elapsed(),
+            secs
+        );
+    }
+
+    #[test]
+    fn accessed() {
+        let mut holder = CacheEntry {
+            data: CacheType::Raw("older".to_string()),
+            last_used: Instant::now() - Duration::from_secs(700),
+        };
+        holder.touch();
+        let held = holder.elapsed();
+        assert!(
+            Duration::from_secs(1) > held,
+            "Duration was {:?}, should have been close to 0s.",
+            held
+        );
+    }
+
+    #[test]
+    fn updated() {
+        let text = "new data";
+        let mut holder = CacheEntry {
+            data: CacheType::Raw("old data".to_string()),
+            last_used: Instant::now() - Duration::from_secs(900),
+        };
+        holder.update(CacheType::Raw(text.to_string()));
+        assert_eq!(holder.to_string(), text);
+        let held = holder.elapsed();
+        assert!(
+            Duration::from_secs(1) > held,
+            "Duration was {:?}, should have been close to 0s.",
+            held
+        );
+    }
+}
+
+#[cfg(test)]
+mod enum_ctype {
+    use super::*;
+
+    #[test]
+    fn bad_file_header() {
+        let mut data: Vec<u8> = Vec::new();
+        let mut ctype = "jlksdfg".as_bytes().to_vec();
+        let mut cdata = "ghjk".as_bytes().to_vec();
+        data.append(&mut ctype);
+        data.push(0);
+        data.append(&mut cdata);
+        match CacheType::from_bytes(data) {
+            Ok(_) => assert!(false, "This should fail."),
+            Err(err) => assert_eq!(err.to_string(), "data corruption"),
+        }
+    }
+
+    #[test]
+    fn incomplete_file() {
+        let mut data: Vec<u8> = Vec::new();
+        let mut ctype = "uoisfde".as_bytes().to_vec();
+        data.append(&mut ctype);
+        match CacheType::from_bytes(data) {
+            Ok(_) => assert!(false, "This should fail."),
+            Err(err) => assert_eq!(err.to_string(), "incomplete file"),
+        }
+    }
+
+    #[test]
+    fn empty_file() {
+        let data: Vec<u8> = Vec::new();
+        match CacheType::from_bytes(data) {
+            Ok(_) => assert!(false, "This should fail."),
+            Err(err) => assert_eq!(err.to_string(), "empty file"),
+        }
+    }
+
+    #[test]
+    fn get_raw_type() {
+        let holder = CacheType::Raw("nothing important".to_string());
+        assert_eq!(holder.entry_type(), "Raw");
+    }
+
+    #[test]
+    fn get_raw_bytes() {
+        let data = "addams";
+        let holder = CacheType::Raw(data.to_string());
+        let mut expected = holder.entry_type().into_bytes();
+        expected.push(0);
+        expected.append(&mut data.as_bytes().to_vec());
+        let output = holder.to_bytes();
+        assert_eq!(output, expected);
+    }
+
+    #[test]
+    fn from_raw_bytes() {
+        let holder = CacheType::Raw("stored item".to_string());
+        let data = holder.to_bytes();
+        let output = CacheType::from_bytes(data).unwrap();
+        assert_eq!(output.to_string(), holder.to_string());
+    }
+
+    #[test]
+    fn get_dbmap_type() {
+        let holder = CacheType::DBMap(Store::new());
+        assert_eq!(holder.entry_type(), "DBMap");
+    }
+
+    #[test]
+    fn get_new_databases_bytes() {
+        let holder = CacheType::DBMap(Store::new());
+        let mut expected = "DBMap".as_bytes().to_vec();
+        expected.push(0);
+        let output = holder.to_bytes();
+        assert_eq!(output, expected);
+    }
+
+    #[test]
+    fn from_new_databases_bytes() {
+        let mut data = "DBMap".as_bytes().to_vec();
+        data.push(0);
+        let output = CacheType::from_bytes(data).unwrap();
+        assert_eq!(output.entry_type(), "DBMap");
+    }
+
+    #[test]
+    fn get_tablemap_type() {
+        let holder = CacheType::TableMap;
+        assert_eq!(holder.entry_type(), "TableMap");
+    }
+
+    #[test]
+    fn get_new_database_bytes() {
+        let holder = CacheType::TableMap;
+        let mut expected = "TableMap".as_bytes().to_vec();
+        expected.push(0);
+        let output = holder.to_bytes();
+        assert_eq!(output, expected);
+    }
+
+    #[test]
+    fn from_new_database_bytes() {
+        let mut data = "TableMap".as_bytes().to_vec();
+        data.push(0);
+        let output = CacheType::from_bytes(data).unwrap();
+        assert_eq!(output.entry_type(), "TableMap");
+    }
+}

src/morethantext/mod.rs

@@ -1,148 +1,186 @@
-pub mod error;
+mod cache;
+mod database;
+mod error;
+mod store;
+mod table;
 
 use async_std::{
-    fs::create_dir,
-    path::Path,
-    sync::{Arc, Mutex},
+    channel::{unbounded, Sender},
+    path::PathBuf,
+    task::spawn,
 };
-use error::DBError;
-use rand::{distributions::Alphanumeric, thread_rng, Rng};
-use std::{collections::HashMap, fmt};
+use cache::Cache;
+use database::Database;
+use error::{ErrorCode, MTTError};
+use store::Store;
+use table::Table;
 
-const DATA: &str = "data";
+const ENTRY: &str = "EntryPoint";
 
-#[derive(Clone)]
-enum CacheEntry {
-    Raw(String),
+#[derive(Debug)]
+pub struct ToCacheMsg<D> {
+    data: D,
+    result: Sender<FromCache>,
 }
 
-impl fmt::Display for CacheEntry {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            CacheEntry::Raw(s) => write!(f, "{}", s),
+#[derive(Debug)]
+pub enum ToCache {
+    Get(ToCacheMsg<String>),
+    Commit(ToCacheMsg<Store>),
+}
+
+#[derive(Clone, Debug)]
+pub enum FromCache {
+    Ok,
+    Str(Store),
+    DB(Database),
+    Error(MTTError),
+}
+
+#[derive(Clone, Debug)]
+pub struct Data<D> {
+    id: Option<String>,
+    data: Option<D>,
+}
+
+impl<D> Data<D> {
+    fn from_id<S>(id: S) -> Self
+    where
+        S: Into<String>,
+    {
+        Self {
+            id: Some(id.into()),
+            data: None,
+        }
+    }
+
+    fn from_data(data: D) -> Self {
+        Self {
+            id: None,
+            data: Some(data),
         }
     }
 }
 
 #[derive(Clone)]
 pub struct MoreThanText {
-    cache: Arc<Mutex<HashMap<String, CacheEntry>>>,
+    to_cache: Sender<ToCache>,
+    entry: Data<Store>,
 }
 
 impl MoreThanText {
-    pub async fn new(dir: &str) -> Result<Self, DBError> {
-        let data_dir = Path::new(dir).join(DATA);
-        if !data_dir.is_dir().await {
-            match create_dir(data_dir).await {
-                Ok(_) => (),
-                Err(err) => {
-                    let mut error = DBError::new("failed to create data directory");
-                    error.add_source(err);
-                    return Err(error);
-                }
-            }
+    fn new(to_cache: Sender<ToCache>) -> Self {
+        Self {
+            to_cache: to_cache,
+            entry: Data::from_id(ENTRY),
         }
-        Ok(Self {
-            cache: Arc::new(Mutex::new(HashMap::new())),
-        })
     }
 
-    async fn add_entry(&self, entry: CacheEntry) -> String {
-        let id: String = thread_rng().sample_iter(&Alphanumeric).take(32).collect();
-        let mut cache = self.cache.lock().await;
-        cache.insert(id.clone(), entry);
-        return id;
+    async fn session(&self) -> Result<Store, MTTError> {
+        let (s, r) = unbounded();
+        let msg = ToCacheMsg {
+            data: ENTRY.to_string(),
+            result: s,
+        };
+        self.to_cache.send(ToCache::Get(msg)).await.unwrap();
+        match r.recv().await.unwrap() {
+            FromCache::Str(store) => Ok(store),
+            FromCache::Error(err) => Err(err),
+            _ => unreachable!(),
+        }
     }
 
-    async fn get_entry(&self, id: &str) -> CacheEntry {
-        let cache = self.cache.lock().await;
-        cache.get(id).unwrap().clone()
-    }
-}
-
-#[cfg(test)]
-mod setup {
-    use super::*;
-    use tempfile::{tempdir, TempDir};
-
-    pub struct MTT {
-        pub db: MoreThanText,
-        pub dir: TempDir,
-    }
-
-    impl MTT {
-        pub async fn new() -> Self {
-            let dir = tempdir().unwrap();
-            let db = MoreThanText::new(dir.path().to_str().unwrap())
-                .await
-                .unwrap();
-            Self { db: db, dir: dir }
+    async fn commit(&self, store: Store) -> Result<(), MTTError> {
+        let (s, r) = unbounded();
+        let msg = ToCacheMsg {
+            data: store,
+            result: s,
+        };
+        self.to_cache.send(ToCache::Commit(msg)).await.unwrap();
+        match r.recv().await.unwrap() {
+            FromCache::Ok => Ok(()),
+            FromCache::Error(err) => Err(err),
+            _ => unreachable!(),
         }
     }
 }
 
 #[cfg(test)]
-mod init {
+mod mtt {
     use super::*;
-    use std::error::Error;
     use tempfile::tempdir;
 
     #[async_std::test]
-    async fn create_data_dir() {
+    async fn create_new() {
         let dir = tempdir().unwrap();
-        MoreThanText::new(dir.path().to_str().unwrap())
-            .await
-            .unwrap();
-        let data_dir = dir.path().join(DATA);
-        assert!(data_dir.is_dir(), "Did not create the data directory.");
-        dir.close().unwrap();
+        let mtt = start_db(dir.path()).await.unwrap();
+        assert_eq!(mtt.entry.id, Some(ENTRY.to_string()));
+        assert!(mtt.entry.data.is_none());
+        let store = mtt.session().await.unwrap();
+        let expected: Vec<String> = Vec::new();
+        assert_eq!(store.list(), expected);
     }
 
     #[async_std::test]
-    async fn existing_data_dir() {
+    async fn commit_db() {
         let dir = tempdir().unwrap();
-        let data_dir = dir.path().join(DATA);
-        create_dir(data_dir).await.unwrap();
-        MoreThanText::new(dir.path().to_str().unwrap())
-            .await
-            .unwrap();
-        dir.close().unwrap();
+        let db = "fred";
+        let mtt = start_db(dir.path()).await.unwrap();
+        let mut store = mtt.session().await.unwrap();
+        store.add(db).unwrap();
+        mtt.commit(store).await.unwrap();
+        let store2 = mtt.session().await.unwrap();
+        assert_eq!(store2.list(), [db]);
     }
 
     #[async_std::test]
-    async fn bad_data_dir() {
-        match MoreThanText::new("kljsdgfhslkfrh").await {
-            Ok(_) => assert!(false, "This test should fail to create a data directory"),
-            Err(err) => {
-                assert_eq!(err.to_string(), "failed to create data directory");
-                assert!(err.source().is_some(), "Must include the source error.");
-            }
-        };
+    async fn commit_from_multiple_sources() {
+        let dir = tempdir().unwrap();
+        let mtt1 = start_db(dir.path()).await.unwrap();
+        let mtt2 = mtt1.clone();
+        let db1 = "first";
+        let db2 = "second";
+        let mut store1 = mtt1.session().await.unwrap();
+        let mut store2 = mtt2.session().await.unwrap();
+        store1.add(db1).unwrap();
+        store2.add(db2).unwrap();
+        mtt1.commit(store1).await.unwrap();
+        mtt2.commit(store2).await.unwrap();
+        let output = mtt1.session().await.unwrap();
+        assert_eq!(output.list(), [db1, db2]);
+    }
+
+    #[async_std::test]
+    async fn fail_on_duplicates() {
+        let dir = tempdir().unwrap();
+        let mtt1 = start_db(dir.path()).await.unwrap();
+        let mtt2 = mtt1.clone();
+        let name = "unique_only";
+        let mut store1 = mtt1.session().await.unwrap();
+        let mut store2 = mtt2.session().await.unwrap();
+        store1.add(name).unwrap();
+        store2.add(name).unwrap();
+        mtt1.commit(store1).await.unwrap();
+        let output = mtt2.commit(store2).await;
+        match output {
+            Ok(_) => assert!(false, "Should have returned an error"),
+            Err(err) => match err.code {
+                ErrorCode::DuplicateDatabase(_) => (),
+                _ => assert!(false, "{:?} is not ErrorCode::DuplicateDatabase", err.code),
+            },
+        }
     }
 }
 
-#[cfg(test)]
-mod cache {
-    use super::*;
-    use setup::MTT;
-
-    #[async_std::test]
-    async fn ids_are_random() {
-        let mtt = MTT::new().await;
-        let data1 = CacheEntry::Raw("one".to_string());
-        let data2 = CacheEntry::Raw("two".to_string());
-        let id1 = mtt.db.add_entry(data1).await;
-        let id2 = mtt.db.add_entry(data2).await;
-        assert_ne!(id1, id2, "Ids should be unique.")
-    }
-
-    #[async_std::test]
-    async fn retrieve_cache() {
-        let mtt = MTT::new().await;
-        let data = "something";
-        let expected = CacheEntry::Raw(data.to_string());
-        let id = mtt.db.add_entry(expected).await;
-        let output = mtt.db.get_entry(&id).await;
-        assert_eq!(output.to_string(), data);
-    }
+pub async fn start_db<P>(dir: P) -> Result<MoreThanText, MTTError>
+where
+    P: Into<PathBuf>,
+{
+    let path = dir.into();
+    let (s, r) = unbounded();
+    spawn(async move {
+        let mut cache = Cache::new(path).await;
+        cache.listen(r).await;
+    });
+    Ok(MoreThanText::new(s))
 }

src/morethantext/store-old.rs

@@ -0,0 +1,306 @@
+use super::{DBError, ErrorCode, FileData, SessionData};
+use std::{collections::HashMap, slice, str};
+
+#[derive(Clone)]
+pub struct Store {
+    db_map: HashMap<String, String>,
+}
+
+impl Store {
+    pub fn new() -> Self {
+        Self {
+            db_map: HashMap::new(),
+        }
+    }
+
+    fn test_key(key: &str) -> Result<(), DBError> {
+        match key {
+            "database" => (),
+            _ => return Err(DBError::new(format!("databases do not have a {}", key))),
+        }
+        Ok(())
+    }
+}
+
+impl FileData<Self> for Store {
+    fn to_bytes(&self) -> Vec<u8> {
+        let mut output = Vec::new();
+        for (name, id) in self.db_map.iter() {
+            output.append(&mut name.as_bytes().to_vec());
+            output.push(0);
+            output.append(&mut id.as_bytes().to_vec());
+            output.push(0);
+        }
+        output
+    }
+
+    fn from_bytes(data: &mut slice::Iter<u8>) -> Result<Self, DBError> {
+        let mut output = Store::new();
+        let mut name: Vec<u8> = Vec::new();
+        let mut id: Vec<u8> = Vec::new();
+        let mut get_id = false;
+        let mut letter: u8;
+        loop {
+            match data.next() {
+                Some(a) => letter = a.clone(),
+                None => {
+                    if !name.is_empty() {
+                        return Err(DBError::from_code(ErrorCode::CorruptFile));
+                    }
+                    break;
+                }
+            }
+            if letter == 0 {
+                if get_id {
+                    let name_holder = match str::from_utf8(&name) {
+                        Ok(item) => item,
+                        Err(_) => return Err(DBError::from_code(ErrorCode::CorruptFile)),
+                    };
+                    let id_holder = match str::from_utf8(&id) {
+                        Ok(item) => item,
+                        Err(_) => return Err(DBError::from_code(ErrorCode::CorruptFile)),
+                    };
+                    match output.add("database", name_holder, id_holder) {
+                        Ok(_) => (),
+                        Err(err) => {
+                            let mut error = DBError::from_code(ErrorCode::CorruptFile);
+                            error.add_source(err);
+                            return Err(error);
+                        }
+                    };
+                    name.clear();
+                    id.clear();
+                }
+                get_id = !get_id;
+            } else {
+                if get_id {
+                    id.push(letter);
+                } else {
+                    name.push(letter);
+                }
+            }
+        }
+        Ok(output)
+    }
+}
+
+impl SessionData for Store {
+    fn add(&mut self, key: &str, value: &str, data: &str) -> Result<Vec<String>, DBError> {
+        match Self::test_key(key) {
+            Ok(_) => (),
+            Err(err) => return Err(err),
+        }
+        match self.db_map.get(value) {
+            Some(_) => return Err(DBError::new(format!("database {} already exists", value))),
+            None => (),
+        }
+        self.db_map.insert(value.to_string(), data.to_string());
+        let mut output = Vec::new();
+        output.push(data.to_string());
+        Ok(output)
+    }
+
+    fn eq(&self, key: &str, value: &str) -> Result<Vec<String>, DBError> {
+        match Self::test_key(key) {
+            Ok(_) => (),
+            Err(err) => return Err(err),
+        }
+        let mut output = Vec::new();
+        match self.db_map.get(value) {
+            Some(data) => output.push(data.to_string()),
+            None => (),
+        }
+        Ok(output)
+    }
+
+    fn list(&self, keys: Vec<&str>) -> Result<Vec<String>, DBError> {
+        for key in keys {
+            match Self::test_key(key) {
+                Ok(_) => (),
+                Err(err) => return Err(err),
+            }
+        }
+        let mut names: Vec<String> = self.db_map.clone().into_keys().collect();
+        names.sort();
+        Ok(names)
+    }
+}
+
+#[cfg(test)]
+mod file_data {
+    use super::*;
+    use std::error::Error;
+
+    #[test]
+    fn to_bytes_new() {
+        let dbs = Store::new();
+        let expected: Vec<u8> = Vec::new();
+        let output = dbs.to_bytes();
+        assert_eq!(output, expected);
+    }
+
+    #[test]
+    fn to_bytes_with_database() {
+        let mut dbs = Store::new();
+        let name = "something";
+        let id = "id";
+        dbs.add("database", name, id).unwrap();
+        let mut expected: Vec<u8> = Vec::new();
+        expected.append(&mut name.as_bytes().to_vec());
+        expected.push(0);
+        expected.append(&mut id.as_bytes().to_vec());
+        expected.push(0);
+        let output = dbs.to_bytes();
+        assert_eq!(output, expected);
+    }
+
+    #[test]
+    fn from_bytes() {
+        let mut dbs = Store::new();
+        dbs.add("database", "one", "1").unwrap();
+        dbs.add("database", "two", "2").unwrap();
+        dbs.add("database", "three", "3").unwrap();
+        let data = dbs.to_bytes();
+        let mut feed = data.iter();
+        let output = Store::from_bytes(&mut feed).unwrap();
+        assert_eq!(output.db_map, dbs.db_map);
+    }
+
+    #[test]
+    fn from_bytes_incomplete_name() -> Result<(), DBError> {
+        let data = "notName".as_bytes();
+        let mut feed = data.iter();
+        match Store::from_bytes(&mut feed) {
+            Ok(_) => Err(DBError::new("should have produced an errpr")),
+            Err(err) => match err.code {
+                ErrorCode::CorruptFile => Ok(()),
+                _ => Err(DBError::new("incorrect error code")),
+            },
+        }
+    }
+
+    #[test]
+    fn from_bytes_incomplete_id() -> Result<(), DBError> {
+        let mut data = "proper".as_bytes().to_vec();
+        data.push(0);
+        data.append(&mut "nope".as_bytes().to_vec());
+        let mut feed = data.iter();
+        match Store::from_bytes(&mut feed) {
+            Ok(_) => Err(DBError::new("should have produced an error")),
+            Err(err) => match err.code {
+                ErrorCode::CorruptFile => Ok(()),
+                _ => Err(DBError::new("incorrect error code")),
+            },
+        }
+    }
+
+    #[test]
+    fn from_bytes_handles_error() -> Result<(), DBError> {
+        let name = "duplicate";
+        let mut data = name.as_bytes().to_vec();
+        data.push(0);
+        data.append(&mut "first".as_bytes().to_vec());
+        data.push(0);
+        data.append(&mut "duplicate".as_bytes().to_vec());
+        data.push(0);
+        data.append(&mut "second".as_bytes().to_vec());
+        data.push(0);
+        let mut feed = data.iter();
+        match Store::from_bytes(&mut feed) {
+            Ok(_) => Err(DBError::new("should have returned an error")),
+            Err(err) => match err.code {
+                ErrorCode::CorruptFile => {
+                    assert!(
+                        err.source().is_some(),
+                        "Should state file corruption cause."
+                    );
+                    assert_eq!(
+                        err.source().unwrap().to_string(),
+                        format!("database {} already exists", name)
+                    );
+                    Ok(())
+                }
+                _ => Err(DBError::new("incorrect error code")),
+            },
+        }
+    }
+}
+
+#[cfg(test)]
+mod session_data {
+    use super::*;
+
+    #[test]
+    fn add_new() {
+        let mut dbs = Store::new();
+        let key = "database";
+        let value = "marvin";
+        let data = "123456";
+        assert_eq!(dbs.add(key, value, data).unwrap(), [data]);
+        let output = dbs.eq(key, value).unwrap();
+        assert_eq!(output, [data]);
+    }
+
+    #[test]
+    fn add_bad_key() {
+        let mut dbs = Store::new();
+        let key = "sdgfjksg";
+        match dbs.add(key, "fred", "barney") {
+            Ok(_) => assert!(false, "Bad keys should produce an error."),
+            Err(err) => assert_eq!(err.to_string(), format!("databases do not have a {}", key)),
+        }
+    }
+
+    #[test]
+    fn get_bad_key() {
+        let dbs = Store::new();
+        let key = "bvdfgert";
+        match dbs.eq(key, "fred") {
+            Ok(_) => assert!(false, "Bad keys should produce an error."),
+            Err(_) => (),
+        }
+    }
+
+    #[test]
+    fn unique_names() {
+        let mut dbs = Store::new();
+        let value = "wilma";
+        dbs.add("database", value, "something").unwrap();
+        match dbs.add("database", value, "overwrite") {
+            Ok(_) => assert!(false, "Duplicate names should produce an error."),
+            Err(err) => assert_eq!(
+                err.to_string(),
+                format!("database {} already exists", value)
+            ),
+        }
+    }
+
+    #[test]
+    fn get_missing() {
+        let dbs = Store::new();
+        let output = dbs.eq("database", "melvin").unwrap();
+        assert_eq!(output, Vec::<String>::new());
+    }
+
+    #[test]
+    fn list_bad_keys() {
+        let dbs = Store::new();
+        let key = "sdfgren";
+        let keys = [key];
+        match dbs.list(keys.to_vec()) {
+            Ok(_) => assert!(false, "Bad keys should error."),
+            Err(err) => assert_eq!(err.to_string(), format!("databases do not have a {}", key)),
+        }
+    }
+
+    #[test]
+    fn list_is_sorted() {
+        let mut dbs = Store::new();
+        let mut data = ["fred", "barney", "wilma", "betty", "pebbles", "bambam"];
+        for db in data {
+            dbs.add("database", db, db).unwrap();
+        }
+        data.sort();
+        assert_eq!(dbs.list(["database"].to_vec()).unwrap(), data);
+    }
+}

src/morethantext/store.rs

@@ -0,0 +1,171 @@
+use super::{Data, Database, ErrorCode, MTTError};
+use std::collections::HashMap;
+
+#[derive(Clone, Debug)]
+pub struct Store {
+    data: HashMap<String, Data<Database>>,
+}
+
+impl Store {
+    pub fn new() -> Self {
+        Self {
+            data: HashMap::new(),
+        }
+    }
+
+    pub fn add<S>(&mut self, name: S) -> Result<(), MTTError>
+    where
+        S: Into<String>,
+    {
+        let db_name = name.into();
+        match self.get(&db_name) {
+            Some(_) => Err(MTTError::from_code(ErrorCode::DuplicateDatabase(db_name))),
+            None => {
+                self.data.insert(db_name, Data::from_data(Database::new()));
+                Ok(())
+            }
+        }
+    }
+
+    pub fn add_by_id<S, D>(&mut self, name: S, id: D) -> Result<(), MTTError>
+    where
+        S: Into<String>,
+        D: Into<String>,
+    {
+        let db_name = name.into();
+        match self.get(&db_name) {
+            Some(_) => Err(MTTError::from_code(ErrorCode::DuplicateDatabase(db_name))),
+            None => {
+                self.data.insert(db_name, Data::from_id(id.into()));
+                Ok(())
+            }
+        }
+    }
+
+    pub fn get(&self, name: &str) -> Option<&Data<Database>> {
+        self.data.get(name)
+    }
+
+    pub fn list(&self) -> Vec<String> {
+        let mut names = Vec::new();
+        for name in self.data.keys() {
+            names.push(name.to_string());
+        }
+        names.sort();
+        names
+    }
+}
+
+#[cfg(test)]
+mod storage {
+    use super::*;
+
+    #[test]
+    fn create_new() {
+        let store = Store::new();
+        let expected: Vec<String> = Vec::new();
+        assert_eq!(store.list(), expected);
+    }
+
+    #[test]
+    fn add_db_by_str() {
+        let mut store = Store::new();
+        let name = "Melvin";
+        store.add(name).unwrap();
+        let output = store.get(name);
+        assert!(output.is_some(), "Get returned none.");
+    }
+
+    #[test]
+    fn add_db_by_string() {
+        let mut store = Store::new();
+        let name = "Marvin";
+        store.add(name.to_string()).unwrap();
+        let output = store.get(name);
+        assert!(output.is_some(), "Get returned none.");
+    }
+
+    #[test]
+    fn fail_on_duplicates() -> Result<(), MTTError> {
+        let mut store = Store::new();
+        let name = "Mickie";
+        store.add(name).unwrap();
+        match store.add(name) {
+            Ok(_) => Err(MTTError::new("duplicates should error")),
+            Err(err) => match err.code {
+                ErrorCode::DuplicateDatabase(db_name) => {
+                    assert_eq!(db_name, name);
+                    Ok(())
+                }
+                _ => Err(MTTError::new(format!("{:?} is not DuplicateDatabase", err))),
+            },
+        }
+    }
+
+    #[test]
+    fn add_using_cache_id() {
+        let mut store = Store::new();
+        let name = "fred";
+        let id = "12345";
+        store.add_by_id(name, id).unwrap();
+        let output = store.get(name).unwrap();
+        assert!(output.data.is_none(), "there should be no data");
+        assert_eq!(output.id, Some(id.to_string()));
+    }
+
+    #[test]
+    fn add_by_cache_id_name_string() {
+        let mut store = Store::new();
+        let name = "barney";
+        let id = "67890";
+        store.add_by_id(name.to_string(), id).unwrap();
+        let output = store.get(name).unwrap();
+        assert!(output.data.is_none(), "there should be no data");
+        assert_eq!(output.id, Some(id.to_string()));
+    }
+
+    #[test]
+    fn no_duplicate_databases_for_add_by_id() {
+        let mut store = Store::new();
+        let name = "betty";
+        store.add_by_id(name, "fghij").unwrap();
+        match store.add_by_id(name, "klmno") {
+            Ok(_) => assert!(false, "Duplicates should error."),
+            Err(err) => match err.code {
+                ErrorCode::DuplicateDatabase(db_name) => assert_eq!(db_name, name),
+                _ => assert!(false, "{:?} is not DuplicateDatabase", err),
+            },
+        }
+    }
+
+    #[test]
+    fn add_by_cache_id_string() {
+        let mut store = Store::new();
+        let name = "wilma";
+        let id = "abcdef";
+        store.add_by_id(name, id.to_string()).unwrap();
+        let output = store.get(name).unwrap();
+        assert!(output.data.is_none(), "there should be no data");
+        assert_eq!(output.id, Some(id.to_string()));
+    }
+
+    #[test]
+    fn get_bad_database() -> Result<(), MTTError> {
+        let store = Store::new();
+        match store.get("missing") {
+            Some(_) => Err(MTTError::new("Should have returned None.")),
+            None => Ok(()),
+        }
+    }
+
+    #[test]
+    fn get_list() {
+        let mut store = Store::new();
+        let mut ids = ["one", "two", "three", "four", "five"];
+        for name in ids {
+            store.add(name.to_string()).unwrap();
+        }
+        ids.sort();
+        assert_eq!(store.list(), ids);
+    }
+}

src/morethantext/table.rs

@@ -0,0 +1,18 @@
+#[derive(Clone, Debug)]
+pub struct Table;
+
+impl Table {
+    pub fn new() -> Self {
+        Self {}
+    }
+}
+
+#[cfg(test)]
+mod tables {
+    use super::*;
+
+    #[test]
+    fn create_new() {
+        Table::new();
+    }
+}