From 3164da0f4c4b36fbacdca6b7ac9a50a6ad7be5da Mon Sep 17 00:00:00 2001
From: Jeff Baskin <jeff.l.baskin@gmail.com>
Date: Mon, 19 Dec 2022 15:21:07 -0500
Subject: [PATCH] Reads cache entry from the drive.

---
 src/morethantext/mod.rs | 42 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 3 deletions(-)

diff --git a/src/morethantext/mod.rs b/src/morethantext/mod.rs
index 9e797f7..d8023e3 100644
--- a/src/morethantext/mod.rs
+++ b/src/morethantext/mod.rs
@@ -1,13 +1,13 @@
 pub mod error;
 
 use async_std::{
-    fs::{create_dir, write},
+    fs::{create_dir, read, write},
     path::Path,
     sync::{Arc, Mutex},
 };
 use error::DBError;
 use rand::{distributions::Alphanumeric, thread_rng, Rng};
-use std::{collections::HashMap, fmt};
+use std::{collections::HashMap, fmt, str};
 
 const DATA: &str = "data";
 
@@ -31,6 +31,19 @@ impl CacheEntry {
         }
         return output;
     }
+
+    fn from_bytes(data: Vec<u8>) -> CacheEntry {
+        let mut data_iter = data.iter();
+        let mut holder: u8 = *data_iter.next().unwrap();
+        while holder != 0 {
+            holder = *data_iter.next().unwrap();
+        }
+        let mut output: Vec<u8> = Vec::new();
+        for letter in data_iter {
+            output.push(letter.clone());
+        }
+        CacheEntry::Raw(str::from_utf8(&output).unwrap().to_string())
+    }
 }
 
 impl fmt::Display for CacheEntry {
@@ -90,7 +103,10 @@ impl MoreThanText {
         let cache = self.cache.lock().await;
         match cache.get(id) {
             Some(id) => Ok(id.clone()),
-            None => Err(DBError::new("cache entry not found")),
+            None => match read(Path::new(&self.dir).join(&id)).await {
+                Ok(content) => Ok(CacheEntry::from_bytes(content)),
+                Err(_) => Err(DBError::new("cache entry not found")),
+            },
         }
     }
 
@@ -213,6 +229,18 @@ mod cache {
         assert_eq!(content, expected.to_bytes());
     }
 
+    #[async_std::test]
+    async fn retrieve_from_disk() {
+        let mtt = MTT::new().await;
+        let id = "someid";
+        let data = CacheEntry::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());
+    }
+
     #[async_std::test]
     async fn store_bad_file() {
         let mtt = MTT::new().await;
@@ -314,4 +342,12 @@ mod cache_entry {
         let output = holder.to_bytes();
         assert_eq!(output, expected);
     }
+
+    #[test]
+    fn raw_from_bytes() {
+        let holder = CacheEntry::Raw("stored item".to_string());
+        let data = holder.to_bytes();
+        let output = CacheEntry::from_bytes(data);
+        assert_eq!(output.to_string(), holder.to_string());
+    }
 }