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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   virtual bool Connect() OVERRIDE WARN_UNUSED_RESULT;
82   virtual void Close() OVERRIDE;
83   virtual base::ProcessId GetPeerPID() const OVERRIDE;
84 
85 #if defined(OS_POSIX) && !defined(OS_NACL)
86   virtual int GetClientFileDescriptor() const OVERRIDE;
87   virtual int TakeClientFileDescriptor() OVERRIDE;
88 #endif  // defined(OS_POSIX) && !defined(OS_NACL)
89 
90   // Used by the source of the messages to send the message to the sink. This
91   // will make a copy of the message and store it in the list.
92   bool OnMessageReceived(const Message& msg);
93 
94   // Returns the number of messages in the queue.
message_count()95   size_t message_count() const { return messages_.size(); }
96 
97   // Clears the message queue of saved messages.
98   void ClearMessages();
99 
100   // Returns the message at the given index in the queue. The index may be out
101   // of range, in which case the return value is NULL. The returned pointer will
102   // only be valid until another message is received or the list is cleared.
103   const Message* GetMessageAt(size_t index) const;
104 
105   // Returns the first message with the given ID in the queue. If there is no
106   // message with the given ID, returns NULL. The returned pointer will only be
107   // valid until another message is received or the list is cleared.
108   const Message* GetFirstMessageMatching(uint32 id) const;
109 
110   // Returns the message with the given ID in the queue. If there is no such
111   // message or there is more than one of that message, this will return NULL
112   // (with the expectation that you'll do an ASSERT_TRUE() on the result).
113   // The returned pointer will only be valid until another message is received
114   // or the list is cleared.
115   const Message* GetUniqueMessageMatching(uint32 id) const;
116 
117   // Adds the given listener as a filter to the TestSink.
118   // When a message is received by the TestSink, it will be dispatched to
119   // the filters, in the order they were added.  If a filter returns true
120   // from OnMessageReceived, subsequent filters will not receive the message
121   // and the TestSink will not store it.
122   void AddFilter(Listener* filter);
123 
124   // Removes the given filter from the TestSink.
125   void RemoveFilter(Listener* filter);
126 
127  private:
128   // The actual list of received messages.
129   std::vector<Message> messages_;
130   ObserverList<Listener> filter_list_;
131 
132   DISALLOW_COPY_AND_ASSIGN(TestSink);
133 };
134 
135 }  // namespace IPC
136 
137 #endif  // IPC_IPC_TEST_SINK_H_
138