device/serial/data_sender.h

   1 // Copyright 2014 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 DEVICE_SERIAL_DATA_SENDER_H_
   6 #define DEVICE_SERIAL_DATA_SENDER_H_
   7
   8 #include <queue>
   9
  10 #include "base/callback.h"
  11 #include "base/memory/linked_ptr.h"
  12 #include "base/strings/string_piece.h"
  13 #include "device/serial/buffer.h"
  14 #include "device/serial/data_stream.mojom.h"
  15 #include "mojo/public/cpp/system/data_pipe.h"
  16
  17 namespace device {
  18
  19 class AsyncWaiter;
  20
  21 // A DataSender sends data to a DataSink.
  22 class DataSender : public serial::DataSinkClient, public mojo::ErrorHandler {
  23  public:
  24   typedef base::Callback<void(uint32_t bytes_sent)> DataSentCallback;
  25   typedef base::Callback<void(uint32_t bytes_sent, int32_t error)>
  26       SendErrorCallback;
  27   typedef base::Callback<void()> CancelCallback;
  28
  29   // Constructs a DataSender to send data to |sink|, using a data pipe with a
  30   // buffer size of |buffer_size|, with connection errors reported as
  31   // |fatal_error_value|.
  32   DataSender(mojo::InterfacePtr<serial::DataSink> sink,
  33              uint32_t buffer_size,
  34              int32_t fatal_error_value);
  35
  36   ~DataSender() override;
  37
  38   // Starts an asynchronous send of |data|. If the send completes successfully,
  39   // |callback| will be called. Otherwise, |error_callback| will be called with
  40   // the error. If there is a cancel in progress or there has been a connection
  41   // error, this will not start a send and returns false. It is the caller's
  42   // responsibility to ensure |data| remains valid until one of |callback| and
  43   // |error_callback| is called.
  44   bool Send(const base::StringPiece& data,
  45             const DataSentCallback& callback,
  46             const SendErrorCallback& error_callback);
  47
  48   // Requests the cancellation of any in-progress sends. Calls to Send() will
  49   // fail until |callback| is called.
  50   bool Cancel(int32_t error, const CancelCallback& callback);
  51
  52  private:
  53   class PendingSend;
  54
  55   // serial::DataSinkClient overrides.
  56   void ReportBytesSent(uint32_t bytes_sent) override;
  57   void ReportBytesSentAndError(
  58       uint32_t bytes_sent,
  59       int32_t error,
  60       const mojo::Callback<void(uint32_t)>& callback) override;
  61
  62   // mojo::ErrorHandler override.
  63   void OnConnectionError() override;
  64
  65   // Copies data from |pending_sends_| into the data pipe and starts |waiter_|
  66   // waiting if the pipe is full. When a PendingSend in |pending_sends_| has
  67   // been fully copied into the data pipe, it moves to |sends_awaiting_ack_|.
  68   void SendInternal();
  69
  70   // Invoked when |handle_| is ready for writes. Calls SendInternal().
  71   void OnDoneWaiting(MojoResult result);
  72
  73   // Dispatches a cancel callback if one is pending.
  74   void RunCancelCallback();
  75
  76   // Shuts down this DataSender and dispatches fatal errors to all pending
  77   // operations.
  78   void ShutDown();
  79
  80   // The control connection to the data sink.
  81   mojo::InterfacePtr<serial::DataSink> sink_;
  82
  83   // The data connection to the data sink.
  84   mojo::ScopedDataPipeProducerHandle handle_;
  85
  86   // The error value to report in the event of a fatal error.
  87   const int32_t fatal_error_value_;
  88
  89   // A waiter used to wait until |handle_| is writable if we are waiting.
  90   scoped_ptr<AsyncWaiter> waiter_;
  91
  92   // A queue of PendingSend that have not yet been fully written to the data
  93   // pipe.
  94   std::queue<linked_ptr<PendingSend> > pending_sends_;
  95
  96   // A queue of PendingSend that have been written to the data pipe, but have
  97   // not yet been acked by the DataSink.
  98   std::queue<linked_ptr<PendingSend> > sends_awaiting_ack_;
  99
 100   // The callback to report cancel completion if a cancel operation is in
 101   // progress.
 102   CancelCallback pending_cancel_;
 103
 104   // Whether we have encountered a fatal error and shut down.
 105   bool shut_down_;
 106
 107   DISALLOW_COPY_AND_ASSIGN(DataSender);
 108 };
 109
 110 }  // namespace device
 111
 112 #endif  // DEVICE_SERIAL_DATA_SENDER_H_