Added retrival function.

src/morethantext/cache.rs

@@ -112,13 +112,38 @@ impl Entry {
         })
     }
 
+    async fn get(filename: &str) -> Result<Self, DBError> {
+        let filepath = Path::new(filename);
+        let content = match read(filepath).await {
+            Ok(text) => text,
+            Err(err) => {
+                let mut error = DBError::new("read error");
+                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::new("read error");
+                error.add_source(err);
+                return Err(error);
+            }
+        };
+        Ok(Self {
+            data: data,
+            filename: filename.to_string(),
+            last_used: Cell::new(Instant::now()),
+        })
+    }
+
     fn elapsed(&self) -> Duration {
         self.last_used.get().elapsed()
     }
 
-    async fn get(&self) -> Result<DataType, DBError> {
+    fn data(&self) -> DataType {
         self.last_used.set(Instant::now());
-        Ok(self.data.clone())
+        self.data.clone()
     }
 
     async fn update(&mut self, data: DataType) -> Result<(), DBError> {
@@ -296,7 +321,7 @@ mod entry {
             Duration::from_secs(1) > item.elapsed(),
             "last_used should have been now."
         );
-        let output = item.get().await.unwrap();
+        let output = item.data();
         assert_eq!(
             data.list(["database"].to_vec()).unwrap(),
             output.list(["database"].to_vec()).unwrap()
@@ -357,7 +382,7 @@ mod entry {
         let item = Entry::new(filename.to_string(), data).await.unwrap();
         item.last_used
             .set(Instant::now() - Duration::from_secs(300));
-        item.get().await.unwrap();
+        item.data();
         assert!(
             Duration::from_secs(1) > item.elapsed(),
             "last_used should have been reset."
@@ -381,7 +406,7 @@ mod entry {
             Duration::from_secs(1) > item.elapsed(),
             "last_used should have been reset."
         );
-        let output = item.get().await.unwrap();
+        let output = item.data();
         assert_eq!(
             data.list(["database"].to_vec()).unwrap(),
             output.list(["database"].to_vec()).unwrap()
@@ -414,6 +439,75 @@ mod entry {
             }
         }
     }
+
+    #[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, 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) => {
+                assert_eq!(err.to_string(), "read error");
+                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(())
+            }
+        }
+    }
+
+    #[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) => {
+                assert_eq!(err.to_string(), "read error");
+                assert!(err.source().is_some(), "Error should have a source.");
+                assert!(
+                    err.source()
+                        .unwrap()
+                        .to_string()
+                        .contains("file corruption"),
+                    "Source Error Message: {}",
+                    err.source().unwrap().to_string()
+                );
+                Ok(())
+            }
+        }
+    }
 }
 
 #[cfg(test)]