ipc/ipc_test_sink.h

   1 // Copyright (c) 2011 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 IPC_IPC_TEST_SINK_H_
   6 #define IPC_IPC_TEST_SINK_H_
   7
   8 #include <utility>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/observer_list.h"
  13 #include "ipc/ipc_channel.h"
  14
  15 namespace IPC {
  16
  17 class Message;
  18
  19 // This test sink provides a "sink" for IPC messages that are sent. It allows
  20 // the caller to query messages received in various different ways.  It is
  21 // designed for tests for objects that use the IPC system.
  22 //
  23 // Typical usage:
  24 //
  25 //   test_sink.ClearMessages();
  26 //   do_something();
  27 //
  28 //   // We should have gotten exactly one update state message.
  29 //   EXPECT_TRUE(test_sink.GetUniqeMessageMatching(ViewHostMsg_Update::ID));
  30 //   // ...and no start load messages.
  31 //   EXPECT_FALSE(test_sink.GetFirstMessageMatching(ViewHostMsg_Start::ID));
  32 //
  33 //   // Now inspect a message. This assumes a message that was declared like
  34 //   // this: IPC_MESSAGE_ROUTED2(ViewMsg_Foo, bool, int)
  35 //   IPC::Message* msg = test_sink.GetFirstMessageMatching(ViewMsg_Foo::ID));
  36 //   ASSERT_TRUE(msg);
  37 //   bool first_param;
  38 //   int second_param;
  39 //   ViewMsg_Foo::Read(msg, &first_param, &second_param);
  40 //
  41 //   // Go on to the next phase of the test.
  42 //   test_sink.ClearMessages();
  43 //
  44 // To read a sync reply, do this:
  45 //
  46 //   IPC::Message* msg = test_sink.GetUniqueMessageMatching(IPC_REPLY_ID);
  47 //   ASSERT_TRUE(msg);
  48 //   TupleTypes<ViewHostMsg_Foo::ReplyParam>::ValueTuple reply_data;
  49 //   EXPECT_TRUE(ViewHostMsg_Foo::ReadReplyParam(msg, &reply_data));
  50 //
  51 // You can also register to be notified when messages are posted to the sink.
  52 // This can be useful if you need to wait for a particular message that will
  53 // be posted asynchronously.  Example usage:
  54 //
  55 //   class MyListener : public IPC::Listener {
  56 //    public:
  57 //     virtual bool OnMessageReceived(const IPC::Message& msg) {
  58 //       <do something with the message>
  59 //       MessageLoop::current()->Quit();
  60 //       return false;  // to store the message in the sink, or true to drop it
  61 //     }
  62 //   };
  63 //
  64 //   MyListener listener;
  65 //   test_sink.AddFilter(&listener);
  66 //   StartSomeAsynchronousProcess(&test_sink);
  67 //   MessageLoop::current()->Run();
  68 //   <inspect the results>
  69 //   ...
  70 //
  71 // To hook up the sink, all you need to do is call OnMessageReceived when a
  72 // message is received.
  73 class TestSink : public Channel {
  74  public:
  75   TestSink();
  76   virtual ~TestSink();
  77
  78   // Interface in IPC::Channel. This copies the message to the sink and then
  79   // deletes it.
  80   virtual bool Send(IPC::Message* message) OVERRIDE;
  81
  82   // Used by the source of the messages to send the message to the sink. This
  83   // will make a copy of the message and store it in the list.
  84   bool OnMessageReceived(const Message& msg);
  85
  86   // Returns the number of messages in the queue.
  87   size_t message_count() const { return messages_.size(); }
  88
  89   // Clears the message queue of saved messages.
  90   void ClearMessages();
  91
  92   // Returns the message at the given index in the queue. The index may be out
  93   // of range, in which case the return value is NULL. The returned pointer will
  94   // only be valid until another message is received or the list is cleared.
  95   const Message* GetMessageAt(size_t index) const;
  96
  97   // Returns the first message with the given ID in the queue. If there is no
  98   // message with the given ID, returns NULL. The returned pointer will only be
  99   // valid until another message is received or the list is cleared.
 100   const Message* GetFirstMessageMatching(uint32 id) const;
 101
 102   // Returns the message with the given ID in the queue. If there is no such
 103   // message or there is more than one of that message, this will return NULL
 104   // (with the expectation that you'll do an ASSERT_TRUE() on the result).
 105   // The returned pointer will only be valid until another message is received
 106   // or the list is cleared.
 107   const Message* GetUniqueMessageMatching(uint32 id) const;
 108
 109   // Adds the given listener as a filter to the TestSink.
 110   // When a message is received by the TestSink, it will be dispatched to
 111   // the filters, in the order they were added.  If a filter returns true
 112   // from OnMessageReceived, subsequent filters will not receive the message
 113   // and the TestSink will not store it.
 114   void AddFilter(Listener* filter);
 115
 116   // Removes the given filter from the TestSink.
 117   void RemoveFilter(Listener* filter);
 118
 119  private:
 120   // The actual list of received messages.
 121   std::vector<Message> messages_;
 122   ObserverList<Listener> filter_list_;
 123
 124   DISALLOW_COPY_AND_ASSIGN(TestSink);
 125 };
 126
 127 }  // namespace IPC
 128
 129 #endif  // IPC_IPC_TEST_SINK_H_