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