1 // Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_BROWSER_MESSAGE_FILTER_H_ 6 #define CONTENT_PUBLIC_BROWSER_BROWSER_MESSAGE_FILTER_H_ 7 8 #include "base/memory/ref_counted.h" 9 #include "base/process/process.h" 10 #include "content/common/content_export.h" 11 #include "content/public/browser/browser_thread.h" 12 #include "ipc/ipc_channel_proxy.h" 13 14 #if defined(OS_WIN) 15 #include "base/synchronization/lock.h" 16 #endif 17 18 namespace base { 19 class TaskRunner; 20 } 21 22 namespace content { 23 struct BrowserMessageFilterTraits; 24 25 // Base class for message filters in the browser process. You can receive and 26 // send messages on any thread. 27 class CONTENT_EXPORT BrowserMessageFilter 28 : public base::RefCountedThreadSafe< 29 BrowserMessageFilter, BrowserMessageFilterTraits>, 30 public IPC::Sender { 31 public: 32 BrowserMessageFilter(); 33 34 // These match the corresponding IPC::ChannelProxy::MessageFilter methods and 35 // are always called on the IO thread. OnFilterAdded(IPC::Channel * channel)36 virtual void OnFilterAdded(IPC::Channel* channel) {} OnFilterRemoved()37 virtual void OnFilterRemoved() {} OnChannelClosing()38 virtual void OnChannelClosing() {} OnChannelConnected(int32 peer_pid)39 virtual void OnChannelConnected(int32 peer_pid) {} 40 41 // Called when the message filter is about to be deleted. This gives 42 // derived classes the option of controlling which thread they're deleted 43 // on etc. 44 virtual void OnDestruct() const; 45 46 // IPC::Sender implementation. Can be called on any thread. Can't send sync 47 // messages (since we don't want to block the browser on any other process). 48 virtual bool Send(IPC::Message* message) OVERRIDE; 49 50 // If you want the given message to be dispatched to your OnMessageReceived on 51 // a different thread, there are two options, either 52 // OverrideThreadForMessage or OverrideTaskRunnerForMessage. 53 // If neither is overriden, the message will be dispatched on the IO thread. 54 55 // If you want the message to be dispatched on a particular well-known 56 // browser thread, change |thread| to the id of the target thread OverrideThreadForMessage(const IPC::Message & message,BrowserThread::ID * thread)57 virtual void OverrideThreadForMessage( 58 const IPC::Message& message, 59 BrowserThread::ID* thread) {} 60 61 // If you want the message to be dispatched via the SequencedWorkerPool, 62 // return a non-null task runner which will target tasks accordingly. 63 // Note: To target the UI thread, please use OverrideThreadForMessage 64 // since that has extra checks to avoid deadlocks. 65 virtual base::TaskRunner* OverrideTaskRunnerForMessage( 66 const IPC::Message& message); 67 68 // Override this to receive messages. 69 // Your function will normally be called on the IO thread. However, if your 70 // OverrideXForMessage modifies the thread used to dispatch the message, 71 // your function will be called on the requested thread. 72 virtual bool OnMessageReceived(const IPC::Message& message, 73 bool* message_was_ok) = 0; 74 75 // Can be called on any thread, after OnChannelConnected is called. 76 base::ProcessHandle PeerHandle(); 77 78 // Can be called on any thread, after OnChannelConnected is called. peer_pid()79 base::ProcessId peer_pid() const { return peer_pid_; } 80 set_peer_pid_for_testing(base::ProcessId peer_pid)81 void set_peer_pid_for_testing(base::ProcessId peer_pid) { 82 peer_pid_ = peer_pid; 83 } 84 85 // Checks that the given message can be dispatched on the UI thread, depending 86 // on the platform. If not, returns false and an error ot the sender. 87 static bool CheckCanDispatchOnUI(const IPC::Message& message, 88 IPC::Sender* sender); 89 90 // Call this if a message couldn't be deserialized. This kills the renderer. 91 // Can be called on any thread. 92 virtual void BadMessageReceived(); 93 94 protected: 95 virtual ~BrowserMessageFilter(); 96 97 private: 98 friend class base::RefCountedThreadSafe<BrowserMessageFilter, 99 BrowserMessageFilterTraits>; 100 101 class Internal; 102 friend class BrowserChildProcessHostImpl; 103 friend class BrowserPpapiHost; 104 friend class RenderProcessHostImpl; 105 106 // This is private because the only classes that need access to it are made 107 // friends above. This is only guaranteed to be valid on creation, after that 108 // this class could outlive the filter. 109 IPC::ChannelProxy::MessageFilter* GetFilter(); 110 111 // This implements IPC::ChannelProxy::MessageFilter so that we can hide that 112 // from child classes. Internal keeps a reference to this class, which is why 113 // there's a weak pointer back. This class could outlive Internal based on 114 // what the child class does in its OnDestruct method. 115 Internal* internal_; 116 117 IPC::Channel* channel_; 118 base::ProcessId peer_pid_; 119 120 #if defined(OS_WIN) 121 base::Lock peer_handle_lock_; 122 base::ProcessHandle peer_handle_; 123 #endif 124 }; 125 126 struct BrowserMessageFilterTraits { DestructBrowserMessageFilterTraits127 static void Destruct(const BrowserMessageFilter* filter) { 128 filter->OnDestruct(); 129 } 130 }; 131 132 } // namespace content 133 134 #endif // CONTENT_PUBLIC_BROWSER_BROWSER_MESSAGE_FILTER_H_ 135