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      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_
     77