remoting/host/native_messaging/native_messaging_reader.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef REMOTING_HOST_NATIVE_MESSAGING_NATIVE_MESSAGING_READER_H_
   6 #define REMOTING_HOST_NATIVE_MESSAGING_NATIVE_MESSAGING_READER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/callback.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "base/platform_file.h"
  13 #include "base/threading/thread.h"
  14
  15 namespace base {
  16 class SequencedTaskRunner;
  17 class Value;
  18 }  // namespace base
  19
  20 namespace net {
  21 class FileStream;
  22 }  // namespace net
  23
  24 namespace remoting {
  25
  26 // This class is used for reading messages from the Native Messaging client
  27 // webapp.
  28 class NativeMessagingReader {
  29  public:
  30   typedef base::Callback<void(scoped_ptr<base::Value>)> MessageCallback;
  31
  32   explicit NativeMessagingReader(base::PlatformFile handle);
  33   ~NativeMessagingReader();
  34
  35   // Begin reading messages from the Native Messaging client webapp, calling
  36   // |message_callback| for each received message, or |eof_callback| if
  37   // EOF or error is encountered. This method is asynchronous - the callbacks
  38   // will be run on the same thread via PostTask. The caller should be prepared
  39   // for these callbacks to be invoked right up until this object is destroyed.
  40   void Start(MessageCallback message_callback, base::Closure eof_callback);
  41
  42  private:
  43   class Core;
  44   friend class Core;
  45
  46   // Wrappers posted to by the read thread to trigger the message and EOF
  47   // callbacks on the caller thread, and have them safely dropped if the reader
  48   // has been deleted before they are processed.
  49   void InvokeMessageCallback(scoped_ptr<base::Value> message);
  50   void InvokeEofCallback();
  51
  52   // Holds the information that the read thread needs to access, such as the
  53   // FileStream, and the TaskRunner used for posting notifications back to this
  54   // class.
  55   scoped_ptr<Core> core_;
  56
  57   // Caller-supplied message and end-of-file callbacks.
  58   MessageCallback message_callback_;
  59   base::Closure eof_callback_;
  60
  61   // Separate thread used to read from the stream without blocking the main
  62   // thread. net::FileStream's async API cannot be used here because, on
  63   // Windows, it requires the file handle to have been opened for overlapped IO.
  64   base::Thread reader_thread_;
  65   scoped_refptr<base::SequencedTaskRunner> read_task_runner_;
  66
  67   // Allows the reader to be deleted safely even when tasks may be pending on
  68   // it.
  69   base::WeakPtrFactory<NativeMessagingReader> weak_factory_;
  70
  71   DISALLOW_COPY_AND_ASSIGN(NativeMessagingReader);
  72 };
  73
  74 }  // namespace remoting
  75
  76 #endif  // REMOTING_HOST_NATIVE_MESSAGING_NATIVE_MESSAGING_READER_H_