1 // Copyright (c) 2013 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 PPAPI_SHARED_IMPL_THREAD_AWARE_CALLBACK_H_ 6 #define PPAPI_SHARED_IMPL_THREAD_AWARE_CALLBACK_H_ 7 8 #include "base/basictypes.h" 9 #include "base/bind.h" 10 #include "base/memory/ref_counted.h" 11 #include "ppapi/shared_impl/ppapi_shared_export.h" 12 #include "ppapi/shared_impl/proxy_lock.h" 13 14 namespace ppapi { 15 16 class MessageLoopShared; 17 18 namespace internal { 19 20 class PPAPI_SHARED_EXPORT ThreadAwareCallbackBase { 21 protected: 22 ThreadAwareCallbackBase(); 23 ~ThreadAwareCallbackBase(); 24 25 static bool HasTargetLoop(); 26 27 void InternalRunOnTargetThread(const base::Closure& closure); 28 29 private: 30 class Core; 31 32 scoped_refptr<MessageLoopShared> target_loop_; 33 scoped_refptr<Core> core_; 34 35 DISALLOW_COPY_AND_ASSIGN(ThreadAwareCallbackBase); 36 }; 37 38 } // namespace internal 39 40 // Some PPB interfaces have methods that set a custom callback. Usually, the 41 // callback has to be called on the same thread as the one it was set on. 42 // ThreadAwareCallback keeps track of the target thread, and posts a task to run 43 // on it if requested from a different thread. 44 // 45 // Please note that: 46 // - Unlike TrackedCallback, there is no restriction on how many times the 47 // callback will be called. 48 // - When a ThreadAwareCallback object is destroyed, all pending tasks to run 49 // the callback will be ignored. It is designed this way so that when the 50 // resource is destroyed or the callback is cancelled by the plugin, we can 51 // simply delete the ThreadAwareCallback object to prevent touching the 52 // callback later. 53 // - When RunOnTargetThread() is called on the target thread, the callback runs 54 // immediately. 55 template <class FuncType> 56 class ThreadAwareCallback : public internal::ThreadAwareCallbackBase { 57 public: 58 // The caller takes ownership of the returned object. 59 // NULL is returned if the current thread doesn't have an associated Pepper 60 // message loop, or |func| is NULL. Create(FuncType func)61 static ThreadAwareCallback* Create(FuncType func) { 62 if (!func || !HasTargetLoop()) 63 return NULL; 64 return new ThreadAwareCallback(func); 65 } 66 ~ThreadAwareCallback()67 ~ThreadAwareCallback() {} 68 RunOnTargetThread()69 void RunOnTargetThread() { InternalRunOnTargetThread(base::Bind(func_)); } 70 71 template <class P1> RunOnTargetThread(const P1 & p1)72 void RunOnTargetThread(const P1& p1) { 73 InternalRunOnTargetThread(base::Bind(func_, p1)); 74 } 75 76 template <class P1, class P2> RunOnTargetThread(const P1 & p1,const P2 & p2)77 void RunOnTargetThread(const P1& p1, const P2& p2) { 78 InternalRunOnTargetThread(base::Bind(func_, p1, p2)); 79 } 80 81 template <class P1, class P2, class P3> RunOnTargetThread(const P1 & p1,const P2 & p2,const P3 & p3)82 void RunOnTargetThread(const P1& p1, const P2& p2, const P3& p3) { 83 InternalRunOnTargetThread(base::Bind(func_, p1, p2, p3)); 84 } 85 86 template <class P1, class P2, class P3, class P4> RunOnTargetThread(const P1 & p1,const P2 & p2,const P3 & p3,const P4 & p4)87 void RunOnTargetThread(const P1& p1, 88 const P2& p2, 89 const P3& p3, 90 const P4& p4) { 91 InternalRunOnTargetThread(base::Bind(func_, p1, p2, p3, p4)); 92 } 93 94 template <class P1, class P2, class P3, class P4, class P5> RunOnTargetThread(const P1 & p1,const P2 & p2,const P3 & p3,const P4 & p4,const P5 & p5)95 void RunOnTargetThread(const P1& p1, 96 const P2& p2, 97 const P3& p3, 98 const P4& p4, 99 const P5& p5) { 100 InternalRunOnTargetThread(base::Bind(func_, p1, p2, p3, p4, p5)); 101 } 102 103 private: ThreadAwareCallback(FuncType func)104 explicit ThreadAwareCallback(FuncType func) : func_(func) {} 105 106 FuncType func_; 107 }; 108 109 } // namespace ppapi 110 111 #endif // PPAPI_SHARED_IMPL_THREAD_AWARE_CALLBACK_H_ 112