Accessing external state in api handlers

src/api/mod.rs

@@ -1,6 +1,9 @@
 use core::str::Utf8Error;
+use core::ops::DerefMut;
 use std::path::PathBuf;
 use std::ops::Deref;
+use std::sync::Arc;
+use std::sync::Mutex;
 
 use iron::prelude::*;
 use iron::status;
@@ -15,15 +18,28 @@ impl From<CollectionError> for IronError {
     fn from(err: CollectionError) -> IronError {
         match err {
             CollectionError::Io(e) => IronError::new(e, status::NotFound),
-            CollectionError::PathDecoding => IronError::new(err, status::InternalServerError)
+            CollectionError::PathDecoding => IronError::new(err, status::InternalServerError),
+            CollectionError::ConflictingMount(_) => IronError::new(err, status::BadRequest),
         }
     }
 }
 
-pub fn get_api_handler() -> Mount {
+pub fn get_api_handler(collection: Arc<Mutex<collection::Collection>>) -> Mount {
     let mut mount = Mount::new();
-    mount.mount("/browse/", self::browse)
-        .mount("/flatten/", self::flatten);
+    {
+        let collection = collection.clone();
+        mount.mount("/browse/", move |request: &mut Request| {
+            let mut acquired_collection = collection.deref().lock().unwrap();
+            self::browse(request, acquired_collection.deref_mut())
+        } );
+    }
+    {
+        let collection = collection.clone();
+        mount.mount("/flatten/", move |request: &mut Request| {
+            let mut acquired_collection = collection.deref().lock().unwrap();
+            self::flatten(request, acquired_collection.deref_mut())
+        } );
+    }
     mount
 }
 
@@ -33,13 +49,13 @@ fn path_from_request(request: &Request) -> Result<PathBuf, Utf8Error> {
     Ok(PathBuf::from(decoded_path.deref()))
 }
 
-fn browse(request: &mut Request) -> IronResult<Response> {
+fn browse(request: &mut Request, collection: &mut collection::Collection) -> IronResult<Response> {
     let path = path_from_request(request);
     if path.is_err() {
         return Ok(Response::with(status::BadRequest));
     }
     let path = path.unwrap();
-    let browse_result = try!(collection::browse(&path));
+    let browse_result = try!(collection.browse(&path));
 
     let result_json = json::encode(&browse_result);
     if result_json.is_err() {
@@ -51,11 +67,11 @@ fn browse(request: &mut Request) -> IronResult<Response> {
     Ok(Response::with((status::Ok, result_json)))
 }
 
-fn flatten(request: &mut Request) -> IronResult<Response> {
+fn flatten(request: &mut Request, collection: &mut collection::Collection) -> IronResult<Response> {
     let path = path_from_request(request);
     if path.is_err() {
         return Ok(Response::with((status::BadRequest)));
     }
-    collection::flatten(&path.unwrap());
+    collection.flatten(&path.unwrap());
     Ok(Response::with((status::Ok, "TODO Flatten data here")))
 }

src/collection/error.rs

@@ -7,6 +7,7 @@ pub enum CollectionError
 {
     PathDecoding,
     Io(io::Error),
+    ConflictingMount(String),
 }
 
 impl From<io::Error> for CollectionError {
@@ -20,6 +21,7 @@ impl error::Error for CollectionError {
         match *self {
             CollectionError::Io(ref err) => err.description(),
             CollectionError::PathDecoding => "Error while decoding a Path as a UTF-8 string",
+            CollectionError::ConflictingMount(_) => "Attempting to mount multiple directories under the same name",
         }
     }
 
@@ -27,6 +29,7 @@ impl error::Error for CollectionError {
         match *self {
             CollectionError::Io(ref err) => Some(err),
             CollectionError::PathDecoding => None,
+            CollectionError::ConflictingMount(_) => None,
         }
     }
 }
@@ -36,6 +39,7 @@ impl fmt::Display for CollectionError {
         match *self {
             CollectionError::Io(ref err) => write!(f, "IO error: {}", err),
             CollectionError::PathDecoding => write!(f, "Path decoding error"),
+            CollectionError::ConflictingMount(ref name) => write!(f, "Mount point {} already has a target directory", name),
         }
     }
 }

src/collection/mod.rs

@@ -4,6 +4,7 @@ use std::path::Path;
 pub use self::error::CollectionError; 
 
 mod error;
+mod vfs;
 
 #[derive(Debug, RustcEncodable)]
 pub struct Song {
@@ -21,36 +22,50 @@ pub enum CollectionFile {
     Song(Song),
 }
 
-pub fn browse(path: &Path) -> Result<Vec<CollectionFile>, CollectionError> {
+pub struct Collection {
+    vfs: vfs::Vfs,
+}
 
-    let full_path = "samplemusic/".to_string() + path.to_str().unwrap(); // TMP use mount directories
-    println!("Browsing: {}", full_path);
-
-    let mut out = vec![];
-    for file in try!(fs::read_dir(full_path)) {
-        let file = try!(file);
-        let file_meta = try!(file.metadata());
-        let file_path = file.path().to_owned();
-        if file_meta.is_file() {
-            let path_string = try!(file_path.to_str().ok_or(CollectionError::PathDecoding)); 
-            let collection_file = CollectionFile::Song(Song {
-                path: path_string.to_string(),
-            });
-            out.push(collection_file);
-        } else if file_meta.is_dir() {
-            let path_string = try!(file_path.to_str().ok_or(CollectionError::PathDecoding)); 
-            let collection_file = CollectionFile::Directory(Directory {
-                path: path_string.to_string(),
-            });
-            out.push(collection_file);
+impl Collection {
+    pub fn new() -> Collection {
+        Collection{
+            vfs: vfs::Vfs::new(),
         }
     }
-
-    Ok(out)
 }
 
-pub fn flatten(path: &Path) -> Vec<CollectionFile> {
-    println!("Flatten {:?}", path);
-    let out = vec![];
-    out
+impl Collection {
+    pub fn browse(&self, path: &Path) -> Result<Vec<CollectionFile>, CollectionError> {
+
+        let full_path = "samplemusic/".to_string() + path.to_str().unwrap(); // TMP use mount directories
+        println!("Browsing: {}", full_path);
+
+        let mut out = vec![];
+        for file in try!(fs::read_dir(full_path)) {
+            let file = try!(file);
+            let file_meta = try!(file.metadata());
+            let file_path = file.path().to_owned();
+            if file_meta.is_file() {
+                let path_string = try!(file_path.to_str().ok_or(CollectionError::PathDecoding)); 
+                let collection_file = CollectionFile::Song(Song {
+                    path: path_string.to_string(),
+                });
+                out.push(collection_file);
+            } else if file_meta.is_dir() {
+                let path_string = try!(file_path.to_str().ok_or(CollectionError::PathDecoding)); 
+                let collection_file = CollectionFile::Directory(Directory {
+                    path: path_string.to_string(),
+                });
+                out.push(collection_file);
+            }
+        }
+
+        Ok(out)
+    }
+
+    pub fn flatten(&self, path: &Path) -> Vec<CollectionFile> {
+        println!("Flatten {:?}", path);
+        let out = vec![];
+        out
+    }
 }

src/collection/vfs.rs

@@ -0,0 +1,35 @@
+use std::collections::HashMap;
+use std::path::PathBuf;
+use std::path::Path;
+
+use collection::error::CollectionError;
+
+pub struct Vfs {
+	mount_points: HashMap<String, PathBuf>,
+}
+
+impl Vfs {
+	pub fn new() -> Vfs {
+		Vfs {
+			mount_points: HashMap::new(),
+		}
+	}
+
+	pub fn mount(&mut self, name: &str, real_path: &Path) -> Result<(), CollectionError>
+	{
+		let name = name.to_string(); 
+		if self.mount_points.contains_key(&name)	{
+			return Err(CollectionError::ConflictingMount(name));
+		}
+		self.mount_points.insert(name, real_path.to_path_buf());
+		Ok(())
+	}
+
+	pub fn real_to_virtual(&self, real_path: &Path) -> Result<(), CollectionError> {
+		Ok(())
+	}
+
+	pub fn virtual_to_real(&self, virtual_path: &Path) -> Result<(), CollectionError> {
+		Ok(())
+	}
+}

src/main.rs

@@ -5,6 +5,9 @@ extern crate rustc_serialize;
 extern crate staticfile;
 extern crate url;
 
+use std::sync::Arc;
+use std::sync::Mutex;
+
 use iron::prelude::*;
 use mount::Mount;
 use staticfile::Static;
@@ -13,8 +16,12 @@ mod api;
 mod collection;
 
 fn main() {
+
+    let collection = collection::Collection::new();
+    let collection = Arc::new(Mutex::new(collection));
+
     let mut mount = Mount::new();
-    let api_handler = api::get_api_handler();
+    let api_handler = api::get_api_handler( collection );
     mount.mount("/static/", Static::new("samplemusic/"))
         .mount("/api/", api_handler);