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