Add in-memory and fix docs

Cargo.toml

@@ -24,20 +24,15 @@ version = "0.7.0"
 optional = true
 version = "0.8.0"
 
-[dependencies.error-chain]
-optional = true
-version = "0.11.0"
-
 [dependencies.serde_yaml]
 optional = true
 version = "0.7"
 
 [dev-dependencies]
-lazy_static = "1.0.0"
 serde_derive = "1"
 tempfile = "2.1"
 
 [features]
-bin = ["bincode", "base64", "error-chain"]
+bin = ["bincode", "base64"]
 yaml = ["serde_yaml"]
 ron_enc = ["ron"]

examples/config.rs

@@ -13,18 +13,17 @@ extern crate rustbreak;
 #[macro_use] extern crate serde_derive;
 #[macro_use] extern crate lazy_static;
 
-use std::fs::File;
 use std::path::PathBuf;
 use std::default::Default;
-use rustbreak::Database;
+use rustbreak::FileDatabase;
 use rustbreak::deser::Yaml;
 
-type DB = Database<Config, File, Yaml>;
+type DB = FileDatabase<Config, Yaml>;
 
 lazy_static! {
     static ref CONFIG: DB = {
-        let db = Database::from_path(Config::default(), "/tmp/config.yml").expect("Create database from path");
-        let db = db.with_deser(Yaml);
+        let db = FileDatabase::from_path(Config::default(), Yaml, "/tmp/config.yml")
+            .expect("Create database from path");
         db.reload().expect("Config to load");
         db
     };

src/lib.rs

@@ -47,9 +47,9 @@
 //!
 //! ```rust
 //! # use std::collections::HashMap;
-//! use rustbreak::Database;
+//! use rustbreak::{MemoryDatabase, deser::Ron};
 //!
-//! let db = Database::<HashMap<String, String>>::memory(HashMap::new());
+//! let db = MemoryDatabase::<HashMap<String, String>, Ron>::memory(HashMap::new(), Ron);
 //!
 //! println!("Writing to Database");
 //! db.write(|db| {
@@ -191,12 +191,11 @@ impl<Data, Back, DeSer> Database<Data, Back, DeSer>
     }
 
     /// Read lock the database and get write access to the `Data` container
-    pub fn read<T>(&self, task: T) -> error::Result<()>
-        where T: FnOnce(&Data)
+    pub fn read<T, R>(&self, task: T) -> error::Result<R>
+        where T: FnOnce(&Data) -> R
     {
         let mut lock = self.data.read().map_err(|_| error::RustbreakErrorKind::PoisonError)?;
-        task(&mut lock);
-        Ok(())
+        Ok(task(&mut lock))
     }
 
     /// Reload the Data from the backend
@@ -253,3 +252,37 @@ impl<Data, DeSer> Database<Data, FileBackend, DeSer>
         })
     }
 }
+
+/// An in memory backend
+///
+/// It is backed by a `Vec<u8>`
+pub struct MemoryBackend(Vec<u8>);
+
+impl Backend for MemoryBackend {
+    fn get_data(&mut self) -> error::Result<Vec<u8>> {
+        Ok(self.0.clone())
+    }
+
+    fn put_data(&mut self, data: &[u8]) -> error::Result<()> {
+        self.0 = data.to_owned();
+        Ok(())
+    }
+}
+
+/// A database backed by a file
+pub type MemoryDatabase<D, DS> = Database<D, MemoryBackend, DS>;
+
+impl<Data, DeSer> Database<Data, MemoryBackend, DeSer>
+    where
+        Data: Serialize + DeserializeOwned + Debug + Clone + Send,
+        DeSer: DeSerializer<Data> + Send + Sync
+{
+    /// Create new FileDatabase from Path
+    pub fn memory(data: Data, deser: DeSer) -> MemoryDatabase<Data, DeSer> {
+        Database {
+            data: RwLock::new(data),
+            backend: Mutex::new(MemoryBackend(vec![])),
+            deser: deser,
+        }
+    }
+}