Revert 116281 - Move paint aggregator and the completion callback factory.

ppapi/cpp/completion_callback.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PPAPI_CPP_COMPLETION_CALLBACK_H_
 #define PPAPI_CPP_COMPLETION_CALLBACK_H_
 
 #include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/cpp/logging.h"
-#include "ppapi/cpp/module.h"
+#include "ppapi/cpp/non_thread_safe_ref_count.h"
 
 /// @file
 /// This file defines the API to create and run a callback.
 namespace pp {
 
 /// This API enables you to implement and receive callbacks when
 /// Pepper operations complete asynchronously.
 class CompletionCallback {
  public:
   /// The default constructor will create a blocking
@@ skipping 127 matching lines @@
 };
 
 /// BlockUntilComplete() is used in place of an actual completion callback
 /// to request blocking behavior. If specified, the calling thread will block
 /// until the function completes. Blocking completion callbacks are only
 /// allowed from background threads.
 ///
 /// @return A <code>CompletionCallback</code> corresponding to a NULL callback.
 CompletionCallback BlockUntilComplete();
 
+/// CompletionCallbackFactory<T> may be used to create CompletionCallback
+/// objects that are bound to member functions.
+///
+/// If a factory is destroyed, then any pending callbacks will be cancelled
+/// preventing any bound member functions from being called.  The CancelAll()
+/// method allows pending callbacks to be cancelled without destroying the
+/// factory.
+///
+/// <strong>Note: </strong><code>CompletionCallbackFactory<T></code> isn't
+/// thread safe, but you can make it more thread-friendly by passing a
+/// thread-safe refcounting class as the second template element. However, it
+/// only guarantees safety for creating a callback from another thread, the
+/// callback itself needs to execute on the same thread as the thread that
+/// creates/destroys the factory. With this restriction, it is safe to create
+/// the <code>CompletionCallbackFactory</code> on the main thread, create
+/// callbacks from any thread and pass them to CallOnMainThread().
+///
+/// <strong>Example: </strong>
+///
+/// @code
+///
+///   class MyHandler {
+///    public:
+///     // If an compiler warns on following using |this| in the initializer
+///     // list, use PP_ALLOW_THIS_IN_INITIALIZER_LIST macro.
+///     MyHandler() : factory_(this), offset_(0) {
+///     }
+///
+///    void ProcessFile(const FileRef& file) {
+///       CompletionCallback cc = factory_.NewRequiredCallback(
+///           &MyHandler::DidOpen);
+///       int32_t rv = fio_.Open(file, PP_FileOpenFlag_Read, cc);
+///       CHECK(rv == PP_OK_COMPLETIONPENDING);
+///     }
+///
+///    private:
+///     CompletionCallback NewCallback() {
+///       return factory_.NewCallback(&MyHandler::DidCompleteIO);
+///     }
+///
+///     void DidOpen(int32_t result) {
+///       if (result == PP_OK) {
+///         // The file is open, and we can begin reading.
+///         offset_ = 0;
+///         ReadMore();
+///       } else {
+///         // Failed to open the file with error given by 'result'.
+///       }
+///     }
+///
+///     void DidRead(int32_t result) {
+///       if (result > 0) {
+///         // buf_ now contains 'result' number of bytes from the file.
+///         ProcessBytes(buf_, result);
+///         offset_ += result;
+///         ReadMore();
+///       } else {
+///         // Done reading (possibly with an error given by 'result').
+///       }
+///     }
+///
+///     void ReadMore() {
+///       CompletionCallback cc =
+///           factory_.NewOptionalCallback(&MyHandler::DidRead);
+///       int32_t rv = fio_.Read(offset_, buf_, sizeof(buf_),
+///                              cc.pp_completion_callback());
+///       if (rv != PP_OK_COMPLETIONPENDING)
+///         cc.Run(rv);
+///     }
+///
+///     void ProcessBytes(const char* bytes, int32_t length) {
+///       // Do work ...
+///     }
+///
+///     pp::CompletionCallbackFactory<MyHandler> factory_;
+///     pp::FileIO fio_;
+///     char buf_[4096];
+///     int64_t offset_;
+///   };
+///
+/// @endcode
+///
+template <typename T, typename RefCount = NonThreadSafeRefCount>
+class CompletionCallbackFactory {
+ public:
+
+  /// This constructor creates a <code>CompletionCallbackFactory</code>
+  /// bound to an object. If the constructor is called without an argument,
+  /// the default value of <code>NULL</code> is used. The user then must call
+  /// Initialize() to initialize the object.
+  ///
+  /// param[in] object Optional parameter. An object whose member functions
+  /// are to be bound to CompletionCallbacks created by this
+  /// <code>CompletionCallbackFactory</code>. The default value of this
+  /// parameter is <code>NULL</code>.
+  explicit CompletionCallbackFactory(T* object = NULL)
+      : object_(object) {
+    InitBackPointer();
+  }
+
+  /// Destructor.
+  ~CompletionCallbackFactory() {
+    ResetBackPointer();
+  }
+
+  /// CancelAll() cancels all <code>CompletionCallbacks</code> allocated from
+  /// this factory.
+  void CancelAll() {
+    ResetBackPointer();
+    InitBackPointer();
+  }
+  /// Initialize() binds the <code>CallbackFactory</code> to a particular
+  /// object. Use this when the object is not available at
+  /// <code>CallbackFactory</code> creation, and the <code>NULL</code> default
+  /// is passed to the constructor. The object may only be initialized once,
+  /// either by the constructor, or by a call to Initialize().
+  ///
+  /// @param[in] object The object whose member functions are to be bound to
+  /// the <code>CompletionCallback</code> created by this
+  /// <code>CompletionCallbackFactory</code>.
+  void Initialize(T* object) {
+    PP_DCHECK(object);
+    PP_DCHECK(!object_);  // May only initialize once!
+    object_ = object;
+  }
+
+  /// GetObject() returns the object that was passed at initialization to
+  /// Intialize().
+  ///
+  /// @return the object passed to the constructor or Intialize().
+  T* GetObject() {
+    return object_;
+  }
+
+  /// NewCallback allocates a new, single-use <code>CompletionCallback</code>.
+  /// The <code>CompletionCallback</code> must be run in order for the memory
+  /// allocated by the methods to be freed.
+  /// NewCallback() is equivalent to NewRequiredCallback() below.
+  ///
+  /// @param[in] method The method to be invoked upon completion of the
+  /// operation.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method>
+  CompletionCallback NewCallback(Method method) {
+    PP_DCHECK(object_);
+    return NewCallbackHelper(Dispatcher0<Method>(method));
+  }
+
+  /// NewRequiredCallback() allocates a new, single-use
+  /// <code>CompletionCallback</code> that will always run. The
+  /// <code>CompletionCallback</code> must be run in order for the memory
+  /// allocated by the methods to be freed.
+  ///
+  /// @param[in] method The method to be invoked upon completion of the
+  /// operation.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method>
+  CompletionCallback NewRequiredCallback(Method method) {
+    CompletionCallback cc = NewCallback(method);
+    cc.set_flags(cc.flags() & ~PP_COMPLETIONCALLBACK_FLAG_OPTIONAL);
+    return cc;
+  }
+
+  /// NewOptionalCallback() allocates a new, single-use
+  /// <code>CompletionCallback</code> that might not run if the method
+  /// taking it can complete synchronously. Thus, if after passing the
+  /// CompletionCallback to a Pepper method, the method does not return
+  /// PP_OK_COMPLETIONPENDING, then you should manually call the
+  /// CompletionCallback's Run method, or memory will be leaked.
+  ///
+  /// @param[in] method The method to be invoked upon completion of the
+  /// operation.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method>
+  CompletionCallback NewOptionalCallback(Method method) {
+    CompletionCallback cc = NewCallback(method);
+    cc.set_flags(cc.flags() | PP_COMPLETIONCALLBACK_FLAG_OPTIONAL);
+    return cc;
+  }
+
+  /// NewCallback() allocates a new, single-use <code>CompletionCallback</code>.
+  /// The <code>CompletionCallback</code> must be run in order for the memory
+  /// allocated by the methods to be freed.
+  /// NewCallback() is equivalent to NewRequiredCallback() below.
+  ///
+  /// @param[in] method The method to be invoked upon completion of the
+  /// operation. Method should be of type:
+  /// <code>void (T::*)(int32_t result, const A& a)</code>
+  ///
+  /// @param[in] a Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method, typename A>
+  CompletionCallback NewCallback(Method method, const A& a) {
+    PP_DCHECK(object_);
+    return NewCallbackHelper(Dispatcher1<Method, A>(method, a));
+  }
+
+  /// NewRequiredCallback() allocates a new, single-use
+  /// <code>CompletionCallback</code> that will always run. The
+  /// <code>CompletionCallback</code> must be run in order for the memory
+  /// allocated by the methods to be freed.
+  ///
+  /// @param[in] method The method to be invoked upon completion of the
+  /// operation. Method should be of type:
+  /// <code>void (T::*)(int32_t result, const A& a)</code>
+  ///
+  /// @param[in] a Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method, typename A>
+  CompletionCallback NewRequiredCallback(Method method, const A& a) {
+    CompletionCallback cc = NewCallback(method, a);
+    cc.set_flags(cc.flags() & ~PP_COMPLETIONCALLBACK_FLAG_OPTIONAL);
+    return cc;
+  }
+
+  /// NewOptionalCallback() allocates a new, single-use
+  /// <code>CompletionCallback</code> that might not run if the method
+  /// taking it can complete synchronously. Thus, if after passing the
+  /// CompletionCallback to a Pepper method, the method does not return
+  /// PP_OK_COMPLETIONPENDING, then you should manually call the
+  /// CompletionCallback's Run method, or memory will be leaked.
+  ///
+  /// @param[in] method The method to be invoked upon completion of the
+  /// operation. Method should be of type:
+  /// <code>void (T::*)(int32_t result, const A& a)</code>
+  ///
+  /// @param[in] a Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method, typename A>
+  CompletionCallback NewOptionalCallback(Method method, const A& a) {
+    CompletionCallback cc = NewCallback(method, a);
+    cc.set_flags(cc.flags() | PP_COMPLETIONCALLBACK_FLAG_OPTIONAL);
+    return cc;
+  }
+
+  /// NewCallback() allocates a new, single-use
+  /// <code>CompletionCallback</code>.
+  /// The <code>CompletionCallback</code> must be run in order for the memory
+  /// allocated by the methods to be freed.
+  /// NewCallback() is equivalent to NewRequiredCallback() below.
+  ///
+  /// @param method The method taking the callback. Method should be of type:
+  /// <code>void (T::*)(int32_t result, const A& a, const B& b)</code>
+  ///
+  /// @param[in] a Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @param[in] b Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method, typename A, typename B>
+  CompletionCallback NewCallback(Method method, const A& a, const B& b) {
+    PP_DCHECK(object_);
+    return NewCallbackHelper(Dispatcher2<Method, A, B>(method, a, b));
+  }
+
+  /// NewRequiredCallback() allocates a new, single-use
+  /// <code>CompletionCallback</code> that will always run. The
+  /// <code>CompletionCallback</code> must be run in order for the memory
+  /// allocated by the methods to be freed.
+  ///
+  /// @param method The method taking the callback. Method should be of type:
+  /// <code>void (T::*)(int32_t result, const A& a, const B& b)</code>
+  ///
+  /// @param[in] a Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @param[in] b Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method, typename A, typename B>
+  CompletionCallback NewRequiredCallback(Method method, const A& a,
+                                         const B& b) {
+    CompletionCallback cc = NewCallback(method, a, b);
+    cc.set_flags(cc.flags() & ~PP_COMPLETIONCALLBACK_FLAG_OPTIONAL);
+    return cc;
+  }
+
+  /// NewOptionalCallback() allocates a new, single-use
+  /// <code>CompletionCallback</code> that might not run if the method
+  /// taking it can complete synchronously. Thus, if after passing the
+  /// CompletionCallback to a Pepper method, the method does not return
+  /// PP_OK_COMPLETIONPENDING, then you should manually call the
+  /// CompletionCallback's Run method, or memory will be leaked.
+  ///
+  /// @param[in] method The method taking the callback. Method should be of
+  /// type:
+  /// <code>void (T::*)(int32_t result, const A& a, const B& b)</code>
+  ///
+  /// @param[in] a Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @param[in] b Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method, typename A, typename B>
+  CompletionCallback NewOptionalCallback(Method method, const A& a,
+                                         const B& b) {
+    CompletionCallback cc = NewCallback(method, a, b);
+    cc.set_flags(cc.flags() | PP_COMPLETIONCALLBACK_FLAG_OPTIONAL);
+    return cc;
+  }
+
+  /// NewCallback() allocates a new, single-use
+  /// <code>CompletionCallback</code>.
+  /// The <code>CompletionCallback</code> must be run in order for the memory
+  /// allocated by the methods to be freed.
+  /// NewCallback() is equivalent to NewRequiredCallback() below.
+  ///
+  /// @param method The method taking the callback. Method should be of type:
+  /// <code>
+  /// void (T::*)(int32_t result, const A& a, const B& b, const C& c)
+  /// </code>
+  ///
+  /// @param[in] a Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @param[in] b Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @param[in] c Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method, typename A, typename B, typename C>
+  CompletionCallback NewCallback(Method method, const A& a, const B& b,
+                                 const C& c) {
+    PP_DCHECK(object_);
+    return NewCallbackHelper(Dispatcher3<Method, A, B, C>(method, a, b, c));
+  }
+
+  /// NewRequiredCallback() allocates a new, single-use
+  /// <code>CompletionCallback</code> that will always run. The
+  /// <code>CompletionCallback</code> must be run in order for the memory
+  /// allocated by the methods to be freed.
+  ///
+  /// @param method The method taking the callback. Method should be of type:
+  /// <code>
+  /// void (T::*)(int32_t result, const A& a, const B& b, const C& c)
+  /// </code>
+  ///
+  /// @param[in] a Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @param[in] b Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @param[in] c Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method, typename A, typename B, typename C>
+  CompletionCallback NewRequiredCallback(Method method, const A& a,
+                                         const B& b, const C& c) {
+    CompletionCallback cc = NewCallback(method, a, b, c);
+    cc.set_flags(cc.flags() & ~PP_COMPLETIONCALLBACK_FLAG_OPTIONAL);
+    return cc;
+  }
+
+  /// NewOptionalCallback() allocates a new, single-use
+  /// <code>CompletionCallback</code> that might not run if the method
+  /// taking it can complete synchronously. Thus, if after passing the
+  /// CompletionCallback to a Pepper method, the method does not return
+  /// PP_OK_COMPLETIONPENDING, then you should manually call the
+  /// CompletionCallback's Run method, or memory will be leaked.
+  ///
+  /// @param[in] method The method taking the callback. Method should be of
+  /// type:
+  /// <code>
+  /// void (T::*)(int32_t result, const A& a, const B& b, const C& c)
+  /// </code>
+  ///
+  /// @param[in] a Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @param[in] b Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @param[in] c Passed to <code>method</code> when the completion callback
+  /// runs.
+  ///
+  /// @return A <code>CompletionCallback</code>.
+  template <typename Method, typename A, typename B, typename C>
+  CompletionCallback NewOptionalCallback(Method method, const A& a,
+                                         const B& b, const C& c) {
+    CompletionCallback cc = NewCallback(method, a, b, c);
+    cc.set_flags(cc.flags() | PP_COMPLETIONCALLBACK_FLAG_OPTIONAL);
+    return cc;
+  }
+
+ private:
+  class BackPointer {
+   public:
+    typedef CompletionCallbackFactory<T, RefCount> FactoryType;
+
+    BackPointer(FactoryType* factory)
+        : factory_(factory) {
+    }
+
+    void AddRef() {
+      ref_.AddRef();
+    }
+
+    void Release() {
+      if (ref_.Release() == 0)
+        delete this;
+    }
+
+    void DropFactory() {
+      factory_ = NULL;
+    }
+
+    T* GetObject() {
+      return factory_ ? factory_->GetObject() : NULL;
+    }
+
+   private:
+    RefCount ref_;
+    FactoryType* factory_;
+  };
+
+  template <typename Dispatcher>
+  class CallbackData {
+   public:
+    CallbackData(BackPointer* back_pointer, const Dispatcher& dispatcher)
+        : back_pointer_(back_pointer),
+          dispatcher_(dispatcher) {
+      back_pointer_->AddRef();
+    }
+
+    ~CallbackData() {
+      back_pointer_->Release();
+    }
+
+    static void Thunk(void* user_data, int32_t result) {
+      Self* self = static_cast<Self*>(user_data);
+      T* object = self->back_pointer_->GetObject();
+      if (object)
+        self->dispatcher_(object, result);
+      delete self;
+    }
+
+   private:
+    typedef CallbackData<Dispatcher> Self;
+    BackPointer* back_pointer_;
+    Dispatcher dispatcher_;
+  };
+
+  template <typename Method>
+  class Dispatcher0 {
+   public:
+    Dispatcher0(Method method) : method_(method) {
+    }
+    void operator()(T* object, int32_t result) {
+      (object->*method_)(result);
+    }
+   private:
+    Method method_;
+  };
+
+  template <typename Method, typename A>
+  class Dispatcher1 {
+   public:
+    Dispatcher1(Method method, const A& a)
+        : method_(method),
+          a_(a) {
+    }
+    void operator()(T* object, int32_t result) {
+      (object->*method_)(result, a_);
+    }
+   private:
+    Method method_;
+    A a_;
+  };
+
+  template <typename Method, typename A, typename B>
+  class Dispatcher2 {
+   public:
+    Dispatcher2(Method method, const A& a, const B& b)
+        : method_(method),
+          a_(a),
+          b_(b) {
+    }
+    void operator()(T* object, int32_t result) {
+      (object->*method_)(result, a_, b_);
+    }
+   private:
+    Method method_;
+    A a_;
+    B b_;
+  };
+
+  template <typename Method, typename A, typename B, typename C>
+  class Dispatcher3 {
+   public:
+    Dispatcher3(Method method, const A& a, const B& b, const C& c)
+        : method_(method),
+          a_(a),
+          b_(b),
+          c_(c) {
+    }
+    void operator()(T* object, int32_t result) {
+      (object->*method_)(result, a_, b_, c_);
+    }
+   private:
+    Method method_;
+    A a_;
+    B b_;
+    C c_;
+  };
+
+  void InitBackPointer() {
+    back_pointer_ = new BackPointer(this);
+    back_pointer_->AddRef();
+  }
+
+  void ResetBackPointer() {
+    back_pointer_->DropFactory();
+    back_pointer_->Release();
+  }
+
+  template <typename Dispatcher>
+  CompletionCallback NewCallbackHelper(const Dispatcher& dispatcher) {
+    PP_DCHECK(object_);  // Expects a non-null object!
+    return CompletionCallback(
+        &CallbackData<Dispatcher>::Thunk,
+        new CallbackData<Dispatcher>(back_pointer_, dispatcher));
+  }
+
+  // Disallowed:
+  CompletionCallbackFactory(const CompletionCallbackFactory&);
+  CompletionCallbackFactory& operator=(const CompletionCallbackFactory&);
+
+  T* object_;
+  BackPointer* back_pointer_;
+};
+
 }  // namespace pp
 
 #endif  // PPAPI_CPP_COMPLETION_CALLBACK_H_