From 6e6de135effc8ea8ae8da276668c26cbf7fb761a Mon Sep 17 00:00:00 2001
From: Jeff Baskin <jeff.l.baskin@gmail.com>
Date: Sun, 22 Jan 2023 14:15:34 -0500
Subject: [PATCH] Added FileData trait to Databases.

---
 src/morethantext/databases.rs | 113 +++++++++++++++++++++++++++++++++-
 src/morethantext/mod.rs       |   7 ++-
 2 files changed, 118 insertions(+), 2 deletions(-)

diff --git a/src/morethantext/databases.rs b/src/morethantext/databases.rs
index 6089d18..7c93e56 100644
--- a/src/morethantext/databases.rs
+++ b/src/morethantext/databases.rs
@@ -1,4 +1,5 @@
-use std::collections::HashMap;
+use super::{DBError, FileData};
+use std::{collections::HashMap, slice, str};
 
 #[derive(Clone)]
 pub struct Databases {
@@ -32,6 +33,54 @@ impl Databases {
     }
 }
 
+impl FileData<Self> for Databases {
+    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 = Databases::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::new("file corruption"));
+                    }
+                    break;
+                }
+            }
+            if letter == 0 {
+                if get_id {
+                    output
+                        .add_database(str::from_utf8(&name).unwrap(), str::from_utf8(&id).unwrap());
+                    name.clear();
+                    id.clear();
+                }
+                get_id = !get_id;
+            } else {
+                if get_id {
+                    id.push(letter);
+                } else {
+                    name.push(letter);
+                }
+            }
+        }
+        Ok(output)
+    }
+}
+
 #[cfg(test)]
 mod functions {
     use super::*;
@@ -79,3 +128,65 @@ mod functions {
         assert_eq!(output, expected);
     }
 }
+
+#[cfg(test)]
+mod filedata {
+    use super::*;
+
+    #[test]
+    fn to_bytes_new() {
+        let dbs = Databases::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 = Databases::new();
+        let name = "something";
+        let id = "id";
+        dbs.add_database(name, id);
+        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 = Databases::new();
+        dbs.add_database("one", "1");
+        dbs.add_database("two", "2");
+        dbs.add_database("three", "3");
+        let data = dbs.to_bytes();
+        let mut feed = data.iter();
+        let output = Databases::from_bytes(&mut feed).unwrap();
+        assert_eq!(output.db_map, dbs.db_map);
+    }
+
+    #[test]
+    fn from_bytes_incomplete_name() {
+        let data = "notName".as_bytes();
+        let mut feed = data.iter();
+        match Databases::from_bytes(&mut feed) {
+            Ok(_) => assert!(false, "This should have failed."),
+            Err(err) => assert_eq!(err.to_string(), "file corruption"),
+        }
+    }
+
+    #[test]
+    fn from_bytes_incomplete_id() {
+        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 Databases::from_bytes(&mut feed) {
+            Ok(_) => assert!(false, "This should have failed."),
+            Err(err) => assert_eq!(err.to_string(), "file corruption"),
+        }
+    }
+}
diff --git a/src/morethantext/mod.rs b/src/morethantext/mod.rs
index 44660f0..f90fb50 100644
--- a/src/morethantext/mod.rs
+++ b/src/morethantext/mod.rs
@@ -12,13 +12,18 @@ use error::DBError;
 use rand::{distributions::Alphanumeric, thread_rng, Rng};
 use std::{
     collections::HashMap,
-    fmt, str,
+    fmt, slice, str,
     time::{Duration, Instant},
 };
 
 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>;
+}
+
 #[derive(Clone)]
 pub enum CacheType {
     Raw(String),