15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2012 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifndef IPC_IPC_CHANNEL_READER_H_ 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define IPC_IPC_CHANNEL_READER_H_ 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 8c2e0dbddbe15c98d52c4786dac06cb8952a8ae6dTorne (Richard Coles)#include "base/basictypes.h" 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "ipc/ipc_channel.h" 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "ipc/ipc_export.h" 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace IPC { 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace internal { 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This class provides common pipe reading functionality for the 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// platform-specific IPC channel implementations. 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// It does the common input buffer management and message dispatch, while the 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// platform-specific parts provide the pipe management through a virtual 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// interface implemented on a per-platform basis. 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Note that there is no "writer" corresponding to this because the code for 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// writing to the channel is much simpler and has very little common 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// functionality that would benefit from being factored out. If we add 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// something like that in the future, it would be more appropriate to add it 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// here (and rename appropriately) rather than writing a different class. 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class ChannelReader { 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) explicit ChannelReader(Listener* listener); 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) virtual ~ChannelReader(); 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void set_listener(Listener* listener) { listener_ = listener; } 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Call to process messages received from the IPC connection and dispatch 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // them. Returns false on channel error. True indicates that everything 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // succeeded, although there may not have been any messages processed. 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool ProcessIncomingMessages(); 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Handles asynchronously read data. 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Optionally call this after returning READ_PENDING from ReadData to 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // indicate that buffer was filled with the given number of bytes of 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // data. See ReadData for more. 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool AsyncReadComplete(int bytes_read); 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns true if the given message is internal to the IPC implementation, 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // like the "hello" message sent on channel set-up. 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool IsInternalMessage(const Message& m); 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 50c2e0dbddbe15c98d52c4786dac06cb8952a8ae6dTorne (Richard Coles) // Returns true if the given message is an Hello message 51c2e0dbddbe15c98d52c4786dac06cb8952a8ae6dTorne (Richard Coles) // sent on channel set-up. 52c2e0dbddbe15c98d52c4786dac06cb8952a8ae6dTorne (Richard Coles) bool IsHelloMessage(const Message& m); 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) protected: 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) enum ReadState { READ_SUCCEEDED, READ_FAILED, READ_PENDING }; 56 57 Listener* listener() const { return listener_; } 58 59 // Populates the given buffer with data from the pipe. 60 // 61 // Returns the state of the read. On READ_SUCCESS, the number of bytes 62 // read will be placed into |*bytes_read| (which can be less than the 63 // buffer size). On READ_FAILED, the channel will be closed. 64 // 65 // If the return value is READ_PENDING, it means that there was no data 66 // ready for reading. The implementation is then responsible for either 67 // calling AsyncReadComplete with the number of bytes read into the 68 // buffer, or ProcessIncomingMessages to try the read again (depending 69 // on whether the platform's async I/O is "try again" or "write 70 // asynchronously into your buffer"). 71 virtual ReadState ReadData(char* buffer, int buffer_len, int* bytes_read) = 0; 72 73 // Loads the required file desciptors into the given message. Returns true 74 // on success. False means a fatal channel error. 75 // 76 // This will read from the input_fds_ and read more handles from the FD 77 // pipe if necessary. 78 virtual bool WillDispatchInputMessage(Message* msg) = 0; 79 80 // Performs post-dispatch checks. Called when all input buffers are empty, 81 // though there could be more data ready to be read from the OS. 82 virtual bool DidEmptyInputBuffers() = 0; 83 84 // Handles internal messages, like the hello message sent on channel startup. 85 virtual void HandleInternalMessage(const Message& msg) = 0; 86 87 private: 88 // Takes the given data received from the IPC channel and dispatches any 89 // fully completed messages. 90 // 91 // Returns true on success. False means channel error. 92 bool DispatchInputData(const char* input_data, int input_data_len); 93 94 Listener* listener_; 95 96 // We read from the pipe into this buffer. Managed by DispatchInputData, do 97 // not access directly outside that function. 98 char input_buf_[Channel::kReadBufferSize]; 99 100 // Large messages that span multiple pipe buffers, get built-up using 101 // this buffer. 102 std::string input_overflow_buf_; 103 104 DISALLOW_COPY_AND_ASSIGN(ChannelReader); 105}; 106 107} // namespace internal 108} // namespace IPC 109 110#endif // IPC_IPC_CHANNEL_READER_H_ 111