cef/include/base/cef_cancelable_callback.h

315 lines
10 KiB
C++

// Copyright (c) 2014 Marshall A. Greenblatt. Portions copyright (c) 2011
// Google Inc. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the name Chromium Embedded
// Framework nor the names of its contributors may be used to endorse
// or promote products derived from this software without specific prior
// written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// CancelableCallback is a wrapper around base::Callback that allows
// cancellation of a callback. CancelableCallback takes a reference on the
// wrapped callback until this object is destroyed or Reset()/Cancel() are
// called.
//
// NOTE:
//
// Calling CancelableCallback::Cancel() brings the object back to its natural,
// default-constructed state, i.e., CancelableCallback::callback() will return
// a null callback.
//
// THREAD-SAFETY:
//
// CancelableCallback objects must be created on, posted to, cancelled on, and
// destroyed on the same thread.
//
//
// EXAMPLE USAGE:
//
// In the following example, the test is verifying that RunIntensiveTest()
// Quit()s the message loop within 4 seconds. The cancelable callback is posted
// to the message loop, the intensive test runs, the message loop is run,
// then the callback is cancelled.
//
// void TimeoutCallback(const std::string& timeout_message) {
// FAIL() << timeout_message;
// MessageLoop::current()->QuitWhenIdle();
// }
//
// CancelableClosure timeout(base::Bind(&TimeoutCallback, "Test timed out."));
// MessageLoop::current()->PostDelayedTask(FROM_HERE, timeout.callback(),
// 4000) // 4 seconds to run.
// RunIntensiveTest();
// MessageLoop::current()->Run();
// timeout.Cancel(); // Hopefully this is hit before the timeout callback runs.
//
#ifndef CEF_INCLUDE_BASE_CEF_CANCELABLE_CALLBACK_H_
#define CEF_INCLUDE_BASE_CEF_CANCELABLE_CALLBACK_H_
#pragma once
#if defined(BASE_CANCELABLE_CALLBACK_H_)
// Do nothing if the Chromium header has already been included.
// This can happen in cases where Chromium code is used directly by the
// client application. When using Chromium code directly always include
// the Chromium header first to avoid type conflicts.
#elif defined(BUILDING_CEF_SHARED)
// When building CEF include the Chromium header directly.
#include "base/cancelable_callback.h"
#else // !BUILDING_CEF_SHARED
// The following is substantially similar to the Chromium implementation.
// If the Chromium implementation diverges the below implementation should be
// updated to match.
#include "include/base/cef_bind.h"
#include "include/base/cef_callback.h"
#include "include/base/cef_build.h"
#include "include/base/cef_logging.h"
#include "include/base/cef_macros.h"
#include "include/base/cef_weak_ptr.h"
#include "include/base/internal/cef_callback_internal.h"
namespace base {
template <typename Sig>
class CancelableCallback;
template <>
class CancelableCallback<void(void)> {
public:
CancelableCallback() : weak_factory_(this) {}
// |callback| must not be null.
explicit CancelableCallback(const base::Callback<void(void)>& callback)
: weak_factory_(this),
callback_(callback) {
DCHECK(!callback.is_null());
InitializeForwarder();
}
~CancelableCallback() {}
// Cancels and drops the reference to the wrapped callback.
void Cancel() {
weak_factory_.InvalidateWeakPtrs();
forwarder_.Reset();
callback_.Reset();
}
// Returns true if the wrapped callback has been cancelled.
bool IsCancelled() const {
return callback_.is_null();
}
// Sets |callback| as the closure that may be cancelled. |callback| may not
// be null. Outstanding and any previously wrapped callbacks are cancelled.
void Reset(const base::Callback<void(void)>& callback) {
DCHECK(!callback.is_null());
// Outstanding tasks (e.g., posted to a message loop) must not be called.
Cancel();
// |forwarder_| is no longer valid after Cancel(), so re-bind.
InitializeForwarder();
callback_ = callback;
}
// Returns a callback that can be disabled by calling Cancel().
const base::Callback<void(void)>& callback() const {
return forwarder_;
}
private:
void Forward() {
callback_.Run();
}
// Helper method to bind |forwarder_| using a weak pointer from
// |weak_factory_|.
void InitializeForwarder() {
forwarder_ = base::Bind(&CancelableCallback<void(void)>::Forward,
weak_factory_.GetWeakPtr());
}
// Used to ensure Forward() is not run when this object is destroyed.
base::WeakPtrFactory<CancelableCallback<void(void)> > weak_factory_;
// The wrapper closure.
base::Callback<void(void)> forwarder_;
// The stored closure that may be cancelled.
base::Callback<void(void)> callback_;
DISALLOW_COPY_AND_ASSIGN(CancelableCallback);
};
template <typename A1>
class CancelableCallback<void(A1)> {
public:
CancelableCallback() : weak_factory_(this) {}
// |callback| must not be null.
explicit CancelableCallback(const base::Callback<void(A1)>& callback)
: weak_factory_(this),
callback_(callback) {
DCHECK(!callback.is_null());
InitializeForwarder();
}
~CancelableCallback() {}
// Cancels and drops the reference to the wrapped callback.
void Cancel() {
weak_factory_.InvalidateWeakPtrs();
forwarder_.Reset();
callback_.Reset();
}
// Returns true if the wrapped callback has been cancelled.
bool IsCancelled() const {
return callback_.is_null();
}
// Sets |callback| as the closure that may be cancelled. |callback| may not
// be null. Outstanding and any previously wrapped callbacks are cancelled.
void Reset(const base::Callback<void(A1)>& callback) {
DCHECK(!callback.is_null());
// Outstanding tasks (e.g., posted to a message loop) must not be called.
Cancel();
// |forwarder_| is no longer valid after Cancel(), so re-bind.
InitializeForwarder();
callback_ = callback;
}
// Returns a callback that can be disabled by calling Cancel().
const base::Callback<void(A1)>& callback() const {
return forwarder_;
}
private:
void Forward(A1 a1) const {
callback_.Run(a1);
}
// Helper method to bind |forwarder_| using a weak pointer from
// |weak_factory_|.
void InitializeForwarder() {
forwarder_ = base::Bind(&CancelableCallback<void(A1)>::Forward,
weak_factory_.GetWeakPtr());
}
// Used to ensure Forward() is not run when this object is destroyed.
base::WeakPtrFactory<CancelableCallback<void(A1)> > weak_factory_;
// The wrapper closure.
base::Callback<void(A1)> forwarder_;
// The stored closure that may be cancelled.
base::Callback<void(A1)> callback_;
DISALLOW_COPY_AND_ASSIGN(CancelableCallback);
};
template <typename A1, typename A2>
class CancelableCallback<void(A1, A2)> {
public:
CancelableCallback() : weak_factory_(this) {}
// |callback| must not be null.
explicit CancelableCallback(const base::Callback<void(A1, A2)>& callback)
: weak_factory_(this),
callback_(callback) {
DCHECK(!callback.is_null());
InitializeForwarder();
}
~CancelableCallback() {}
// Cancels and drops the reference to the wrapped callback.
void Cancel() {
weak_factory_.InvalidateWeakPtrs();
forwarder_.Reset();
callback_.Reset();
}
// Returns true if the wrapped callback has been cancelled.
bool IsCancelled() const {
return callback_.is_null();
}
// Sets |callback| as the closure that may be cancelled. |callback| may not
// be null. Outstanding and any previously wrapped callbacks are cancelled.
void Reset(const base::Callback<void(A1, A2)>& callback) {
DCHECK(!callback.is_null());
// Outstanding tasks (e.g., posted to a message loop) must not be called.
Cancel();
// |forwarder_| is no longer valid after Cancel(), so re-bind.
InitializeForwarder();
callback_ = callback;
}
// Returns a callback that can be disabled by calling Cancel().
const base::Callback<void(A1, A2)>& callback() const {
return forwarder_;
}
private:
void Forward(A1 a1, A2 a2) const {
callback_.Run(a1, a2);
}
// Helper method to bind |forwarder_| using a weak pointer from
// |weak_factory_|.
void InitializeForwarder() {
forwarder_ = base::Bind(&CancelableCallback<void(A1, A2)>::Forward,
weak_factory_.GetWeakPtr());
}
// Used to ensure Forward() is not run when this object is destroyed.
base::WeakPtrFactory<CancelableCallback<void(A1, A2)> > weak_factory_;
// The wrapper closure.
base::Callback<void(A1, A2)> forwarder_;
// The stored closure that may be cancelled.
base::Callback<void(A1, A2)> callback_;
DISALLOW_COPY_AND_ASSIGN(CancelableCallback);
};
typedef CancelableCallback<void(void)> CancelableClosure;
} // namespace base
#endif // !BUILDING_CEF_SHARED
#endif // CEF_INCLUDE_BASE_CEF_CANCELABLE_CALLBACK_H_