content/media/plugins/MediaResourceServer.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6 #if !defined(MediaResourceServer_h_)
   7 #define MediaResourceServer_h_
   8
   9 #include <map>
  10 #include "nsIServerSocket.h"
  11 #include "MediaResource.h"
  12
  13 namespace mozilla {
  14
  15 class MediaResource;
  16
  17 /*
  18   MediaResourceServer instantiates a socket server that understands
  19   HTTP requests for MediaResource instances. The server runs on an
  20   automatically selected port and MediaResource instances are registered.
  21   The registration returns a string URL than can be used to fetch the
  22   resource. That URL contains a randomly generated path to make it
  23   difficult for other local applications on the device to guess it.
  24
  25   The HTTP protocol is limited in that it supports only what the
  26   Android DataSource implementation uses to fetch media. It
  27   understands HTTP GET and byte range requests.
  28
  29   The intent of this class is to be used in Media backends that
  30   have a system component that does its own network requests. These
  31   requests are made against this server which then uses standard
  32   Gecko network requests and media cache usage.
  33
  34   The MediaResourceServer can be instantiated on any thread and
  35   its methods are threadsafe - they can be called on any thread.
  36   The server socket itself is always run on the main thread and
  37   this is done by the Start() static method by synchronously
  38   dispatching to the main thread.
  39 */
  40 class MediaResourceServer : public nsRunnable
  41 {
  42 private:
  43   // Mutex protecting private members of MediaResourceServer.
  44   // All member variables below this point in the class definition
  45   // must acquire the mutex before access.
  46   mozilla::Mutex mMutex;
  47
  48   // Server socket used to listen for incoming connections
  49   nsCOMPtr<nsIServerSocket> mSocket;
  50
  51   // Mapping between MediaResource URL's to the MediaResource
  52   // object served at that URL.
  53   typedef std::map<nsCString,
  54                   nsRefPtr<mozilla::MediaResource> > ResourceMap;
  55   ResourceMap mResources;
  56
  57   // Create a MediaResourceServer that will listen on an automatically
  58   // selected port when started. This is private as it should only be
  59   // called internally from the public 'Start' method.
  60   MediaResourceServer();
  61   NS_IMETHOD Run();
  62
  63   // Append a random URL path to a string. This is used for creating a
  64   // unique URl for a resource which helps prevent malicious software
  65   // running on the same machine as the server from guessing the URL
  66   // and accessing video data.
  67   nsresult AppendRandomPath(nsCString& aURL);
  68
  69 public:
  70   // Create a MediaResourceServer and start it listening. This call will
  71   // perform a synchronous request on the main thread.
  72   static already_AddRefed<MediaResourceServer> Start();
  73
  74   // Stops the server from listening and accepting further connections.
  75   void Stop();
  76
  77   // Add a MediaResource to be served by this server. Stores the
  78   // absolute URL that can be used to access the resource in 'aUrl'.
  79   nsresult AddResource(mozilla::MediaResource* aResource, nsCString& aUrl);
  80
  81   // Remove a MediaResource so it is no longer served by this server.
  82   // The URL provided must match exactly that provided by a previous
  83   // call to "AddResource".
  84   void RemoveResource(nsCString const& aUrl);
  85
  86   // Returns the prefix for HTTP requests to the server. This plus
  87   // the result of AddResource results in an Absolute URL.
  88   nsCString GetURLPrefix();
  89
  90   // Returns the resource asociated with a given URL
  91   already_AddRefed<mozilla::MediaResource> GetResource(nsCString const& aUrl);
  92 };
  93
  94 } // namespace mozilla
  95
  96 #endif