Make backend generic over Read/Write

libimagstore/src/file_abstraction/stdio/mapper/json.rs

@@ -69,7 +69,7 @@ impl JsonMapper {
 }
 
 impl Mapper for JsonMapper {
-    fn read_to_fs(&self, mut r: Box<Read>, hm: &mut HashMap<PathBuf, Cursor<Vec<u8>>>)   -> Result<()> {
+    fn read_to_fs<R: Read>(&self, r: &mut R, hm: &mut HashMap<PathBuf, Cursor<Vec<u8>>>)   -> Result<()> {
         let mut document = {
             let mut s = String::new();
             try!(r.read_to_string(&mut s).map_err_into(SEK::IoError));
@@ -102,7 +102,7 @@ impl Mapper for JsonMapper {
         Ok(())
     }
 
-    fn fs_to_write(&self, hm: &mut HashMap<PathBuf, Cursor<Vec<u8>>>, out: &mut Write) -> Result<()> {
+    fn fs_to_write<W: Write>(&self, hm: &mut HashMap<PathBuf, Cursor<Vec<u8>>>, out: &mut W) -> Result<()> {
         #[derive(Serialize)]
         struct OutDocument {
             version: String,
@@ -155,11 +155,11 @@ mod test {
           }
         }
         "#;
-        let json    = Cursor::new(String::from(json).into_bytes());
-        let mapper  = JsonMapper::new();
-        let mut hm  = HashMap::new();
+        let mut json = Cursor::new(String::from(json).into_bytes());
+        let mapper   = JsonMapper::new();
+        let mut hm   = HashMap::new();
 
-        let io_res  = mapper.read_to_fs(Box::new(json), &mut hm);
+        let io_res  = mapper.read_to_fs(&mut json, &mut hm);
         assert!(io_res.is_ok());
 
         assert_eq!(1, hm.len()); // we should have exactly one entry

libimagstore/src/file_abstraction/stdio/mapper/mod.rs

@@ -24,8 +24,8 @@ use std::path::PathBuf;
 use store::Result;
 
 pub trait Mapper {
-    fn read_to_fs(&self, Box<Read>, &mut HashMap<PathBuf, Cursor<Vec<u8>>>)   -> Result<()>;
-    fn fs_to_write(&self, &mut HashMap<PathBuf, Cursor<Vec<u8>>>, &mut Write) -> Result<()>;
+    fn read_to_fs<R: Read>(&self, &mut R, &mut HashMap<PathBuf, Cursor<Vec<u8>>>)   -> Result<()>;
+    fn fs_to_write<W: Write>(&self, &mut HashMap<PathBuf, Cursor<Vec<u8>>>, &mut W) -> Result<()>;
 }
 
 pub mod json;

libimagstore/src/file_abstraction/stdio/mod.rs

@@ -17,6 +17,7 @@
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 //
 
+use std::rc::Rc;
 use std::cell::RefCell;
 use std::collections::HashMap;
 use std::fmt::Debug;
@@ -43,25 +44,27 @@ use self::mapper::Mapper;
 // Because this is not exported in super::inmemory;
 type Backend = Arc<Mutex<RefCell<HashMap<PathBuf, Cursor<Vec<u8>>>>>>;
 
-pub struct StdIoFileAbstraction<M: Mapper> {
+pub struct StdIoFileAbstraction<W: Write, M: Mapper> {
     mapper: M,
     mem: InMemoryFileAbstraction,
-    out: Box<Write>,
+    out: Rc<RefCell<W>>,
 }
 
-impl<M> Debug for StdIoFileAbstraction<M>
-    where M: Mapper
+impl<W, M> Debug for StdIoFileAbstraction<W, M>
+    where M: Mapper,
+          W: Write
 {
     fn fmt(&self, f: &mut Formatter) -> Result<(), FmtError> {
         write!(f, "StdIoFileAbstraction({:?}", self.mem)
     }
 }
 
-impl<M> StdIoFileAbstraction<M>
-    where M: Mapper
+impl<W, M> StdIoFileAbstraction<W, M>
+    where M: Mapper,
+          W: Write
 {
 
-    pub fn new(in_stream: Box<Read>, out_stream: Box<Write>, mapper: M) -> Result<StdIoFileAbstraction<M>, SE> {
+    pub fn new<R: Read>(in_stream: &mut R, out_stream: Rc<RefCell<W>>, mapper: M) -> Result<StdIoFileAbstraction<W, M>, SE> {
         let mem = InMemoryFileAbstraction::new();
 
         {
@@ -85,13 +88,18 @@ impl<M> StdIoFileAbstraction<M>
 
 }
 
-impl<M> Drop for StdIoFileAbstraction<M>
-    where M: Mapper
+impl<W, M> Drop for StdIoFileAbstraction<W, M>
+    where M: Mapper,
+          W: Write
 {
     fn drop(&mut self) {
+        use std::ops::DerefMut;
+
         let fill_res = match self.mem.backend().lock() {
             Err(_) => Err(SEK::LockError.into_error()),
-            Ok(mut mtx) => self.mapper.fs_to_write(mtx.get_mut(), &mut *self.out)
+            Ok(mut mtx) => {
+                self.mapper.fs_to_write(mtx.get_mut(), self.out.borrow_mut().deref_mut())
+            },
         };
 
         // We can do nothing but end this here with a trace.
@@ -101,7 +109,7 @@ impl<M> Drop for StdIoFileAbstraction<M>
     }
 }
 
-impl<M: Mapper> FileAbstraction for StdIoFileAbstraction<M> {
+impl<W: Write, M: Mapper> FileAbstraction for StdIoFileAbstraction<W, M> {
 
     fn remove_file(&self, path: &PathBuf) -> Result<(), SE> {
         self.mem.remove_file(path)