Added last access time to cache.
This commit is contained in:
		@@ -7,19 +7,19 @@ use async_std::{
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};
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use error::DBError;
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use rand::{distributions::Alphanumeric, thread_rng, Rng};
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use std::{collections::HashMap, fmt, str};
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use std::{collections::HashMap, fmt, str, time::Instant};
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const DATA: &str = "data";
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#[derive(Clone)]
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enum CacheEntry {
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enum CacheType {
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    Raw(String),
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}
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impl CacheEntry {
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impl CacheType {
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    fn entry_type(&self) -> String {
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        match self {
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            CacheEntry::Raw(_) => "Raw".to_string(),
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            CacheType::Raw(_) => "Raw".to_string(),
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        }
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    }
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@@ -27,12 +27,12 @@ impl CacheEntry {
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        let mut output = self.entry_type().into_bytes();
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        output.push(0);
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        match self {
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            CacheEntry::Raw(s) => output.append(&mut s.as_bytes().to_vec()),
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            CacheType::Raw(s) => output.append(&mut s.as_bytes().to_vec()),
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        }
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        return output;
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    }
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    fn from_bytes(data: Vec<u8>) -> CacheEntry {
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    fn from_bytes(data: Vec<u8>) -> CacheType {
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        let mut data_iter = data.iter();
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        let mut holder: u8 = *data_iter.next().unwrap();
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        while holder != 0 {
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@@ -42,15 +42,36 @@ impl CacheEntry {
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        for letter in data_iter {
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            output.push(letter.clone());
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        }
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        CacheEntry::Raw(str::from_utf8(&output).unwrap().to_string())
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        CacheType::Raw(str::from_utf8(&output).unwrap().to_string())
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    }
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}
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impl fmt::Display for CacheType {
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    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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        match self {
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            CacheType::Raw(s) => write!(f, "{}", s),
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        }
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    }
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}
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#[derive(Clone)]
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struct CacheEntry {
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    data: CacheType,
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    last_used: Instant,
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}
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impl CacheEntry {
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    fn new(data: CacheType) -> Self {
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        Self {
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            data: data,
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            last_used: Instant::now(),
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        }
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    }
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}
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impl fmt::Display for CacheEntry {
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    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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        match self {
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            CacheEntry::Raw(s) => write!(f, "{}", s),
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        }
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        write!(f, "{}", self.data)
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    }
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}
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@@ -79,7 +100,7 @@ impl MoreThanText {
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        })
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    }
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    async fn add_entry(&self, entry: CacheEntry) -> Result<String, DBError> {
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    async fn add_entry(&self, entry: CacheType) -> Result<String, DBError> {
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        let mut id: String = "".to_string();
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        let mut dup = true;
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        while dup {
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@@ -95,7 +116,8 @@ impl MoreThanText {
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            }
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        };
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        let mut cache = self.cache.lock().await;
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        cache.insert(id.clone(), entry);
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        let data = CacheEntry::new(entry);
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        cache.insert(id.clone(), data);
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        Ok(id)
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    }
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@@ -104,13 +126,16 @@ impl MoreThanText {
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        match cache.get(id) {
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            Some(id) => Ok(id.clone()),
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            None => match read(Path::new(&self.dir).join(&id)).await {
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                Ok(content) => Ok(CacheEntry::from_bytes(content)),
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                Ok(content) => {
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                    let data = CacheType::from_bytes(content);
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                    Ok(CacheEntry::new(data))
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                }
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                Err(_) => Err(DBError::new("cache entry not found")),
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            },
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        }
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    }
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    async fn update_entry(&self, id: &str, entry: CacheEntry) -> Result<(), DBError> {
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    async fn update_entry(&self, id: &str, entry: CacheType) -> Result<(), DBError> {
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        match self.get_entry(id).await {
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            Ok(_) => (),
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            Err(err) => return Err(err),
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@@ -124,7 +149,8 @@ impl MoreThanText {
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            }
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        }
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        let mut cache = self.cache.lock().await;
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        cache.insert(id.to_string(), entry);
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        let data = CacheEntry::new(entry);
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        cache.insert(id.to_string(), data);
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        Ok(())
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    }
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}
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@@ -208,8 +234,8 @@ mod cache {
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    #[async_std::test]
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    async fn entry_ids_are_random() {
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        let mtt = MTT::new().await;
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        let data1 = CacheEntry::Raw("one".to_string());
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        let data2 = CacheEntry::Raw("two".to_string());
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        let data1 = CacheType::Raw("one".to_string());
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        let data2 = CacheType::Raw("two".to_string());
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        let id1 = mtt.db.add_entry(data1).await.unwrap();
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        let id2 = mtt.db.add_entry(data2).await.unwrap();
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        assert_ne!(id1, id2, "Ids should be unique.")
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@@ -219,7 +245,7 @@ mod cache {
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    async fn store_cache() {
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        let mtt = MTT::new().await;
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        let data = "something";
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        let expected = CacheEntry::Raw(data.to_string());
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        let expected = CacheType::Raw(data.to_string());
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        let id = mtt.db.add_entry(expected.clone()).await.unwrap();
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        let output = mtt.db.get_entry(&id).await.unwrap();
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        assert_eq!(output.to_string(), data);
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@@ -233,7 +259,7 @@ mod cache {
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    async fn retrieve_from_disk() {
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        let mtt = MTT::new().await;
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        let id = "someid";
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        let data = CacheEntry::Raw("stored".to_string());
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        let data = CacheType::Raw("stored".to_string());
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        write(mtt.dir.path().join(DATA).join(id), data.to_bytes())
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            .await
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            .unwrap();
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@@ -246,7 +272,7 @@ mod cache {
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        let mtt = MTT::new().await;
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        let msg = "could not write to file";
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        mtt.create_io_error().await;
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        match mtt.db.add_entry(CacheEntry::Raw("fail".to_string())).await {
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        match mtt.db.add_entry(CacheType::Raw("fail".to_string())).await {
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            Ok(_) => assert!(false, "This test should fail."),
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            Err(err) => {
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                assert_eq!(err.to_string(), "data write");
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@@ -271,11 +297,11 @@ mod cache {
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        let mtt = MTT::new().await;
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        let id = mtt
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            .db
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            .add_entry(CacheEntry::Raw("same".to_string()))
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            .add_entry(CacheType::Raw("same".to_string()))
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            .await
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            .unwrap();
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        let expected = "different";
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        let expect = CacheEntry::Raw(expected.to_string());
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        let expect = CacheType::Raw(expected.to_string());
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        mtt.db.update_entry(&id, expect.clone()).await.unwrap();
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        let output = mtt.db.get_entry(&id).await.unwrap();
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        assert_eq!(output.to_string(), expected);
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@@ -288,7 +314,7 @@ mod cache {
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        let mtt = MTT::new().await;
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        match mtt
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            .db
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            .update_entry("wilma", CacheEntry::Raw("wrong".to_string()))
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            .update_entry("wilma", CacheType::Raw("wrong".to_string()))
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            .await
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        {
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            Ok(_) => assert!(false, "Bad id should raise an error."),
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@@ -302,13 +328,13 @@ mod cache {
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        let msg = "could not write to file";
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        let id = mtt
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            .db
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            .add_entry(CacheEntry::Raw("fleeting".to_string()))
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            .add_entry(CacheType::Raw("fleeting".to_string()))
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            .await
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            .unwrap();
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        mtt.create_io_error().await;
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        match mtt
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            .db
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            .update_entry(&id, CacheEntry::Raw("failure".to_string()))
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            .update_entry(&id, CacheType::Raw("failure".to_string()))
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            .await
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        {
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            Ok(_) => assert!(false, "This should produce a write failure."),
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@@ -328,14 +354,14 @@ mod cache_entry {
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    #[test]
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    fn raw_get_type() {
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        let holder = CacheEntry::Raw("nothing important".to_string());
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        let holder = CacheType::Raw("nothing important".to_string());
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        assert_eq!(holder.entry_type(), "Raw");
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    }
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    #[test]
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    fn raw_get_bytes() {
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        let data = "addams";
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        let holder = CacheEntry::Raw(data.to_string());
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        let holder = CacheType::Raw(data.to_string());
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        let mut expected = holder.entry_type().into_bytes();
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        expected.push(0);
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        expected.append(&mut data.as_bytes().to_vec());
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@@ -345,9 +371,9 @@ mod cache_entry {
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    #[test]
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    fn raw_from_bytes() {
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        let holder = CacheEntry::Raw("stored item".to_string());
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        let holder = CacheType::Raw("stored item".to_string());
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        let data = holder.to_bytes();
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        let output = CacheEntry::from_bytes(data);
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        let output = CacheType::from_bytes(data);
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        assert_eq!(output.to_string(), holder.to_string());
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    }
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}
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