forked from cztomczak/cefpython
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathcef_callback_helpers.h
More file actions
261 lines (226 loc) · 8.92 KB
/
cef_callback_helpers.h
File metadata and controls
261 lines (226 loc) · 8.92 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
// Copyright (c) 2014 Marshall A. Greenblatt. Portions copyright (c) 2012
// 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.
// This defines helpful methods for dealing with Callbacks. Because Callbacks
// are implemented using templates, with a class per callback signature, adding
// methods to Callback<> itself is unattractive (lots of extra code gets
// generated). Instead, consider adding methods here.
#ifndef CEF_INCLUDE_BASE_CEF_CALLBACK_HELPERS_H_
#define CEF_INCLUDE_BASE_CEF_CALLBACK_HELPERS_H_
#pragma once
#if defined(USING_CHROMIUM_INCLUDES)
// When building CEF include the Chromium header directly.
#include "base/functional/callback_helpers.h"
#else // !USING_CHROMIUM_INCLUDES
// The following is substantially similar to the Chromium implementation.
// If the Chromium implementation diverges the below implementation should be
// updated to match.
#include <atomic>
#include <memory>
#include <type_traits>
#include <utility>
#include "include/base/cef_bind.h"
#include "include/base/cef_callback.h"
#include "include/base/cef_logging.h"
namespace base {
namespace internal {
template <typename T>
struct IsBaseCallbackImpl : std::false_type {};
template <typename R, typename... Args>
struct IsBaseCallbackImpl<OnceCallback<R(Args...)>> : std::true_type {};
template <typename R, typename... Args>
struct IsBaseCallbackImpl<RepeatingCallback<R(Args...)>> : std::true_type {};
template <typename T>
struct IsOnceCallbackImpl : std::false_type {};
template <typename R, typename... Args>
struct IsOnceCallbackImpl<OnceCallback<R(Args...)>> : std::true_type {};
} // namespace internal
///
/// IsBaseCallback<T>::value is true when T is any of the Closure or Callback
/// family of types.
///
template <typename T>
using IsBaseCallback = internal::IsBaseCallbackImpl<std::decay_t<T>>;
///
/// IsOnceCallback<T>::value is true when T is a OnceClosure or OnceCallback
/// type.
///
template <typename T>
using IsOnceCallback = internal::IsOnceCallbackImpl<std::decay_t<T>>;
///
/// SFINAE friendly enabler allowing to overload methods for both Repeating and
/// OnceCallbacks.
///
/// Usage:
/// <pre>
/// template <template <typename> class CallbackType,
/// ... other template args ...,
/// typename = EnableIfIsBaseCallback<CallbackType>>
/// void DoStuff(CallbackType<...> cb, ...);
/// </pre>
///
template <template <typename> class CallbackType>
using EnableIfIsBaseCallback =
std::enable_if_t<IsBaseCallback<CallbackType<void()>>::value>;
namespace internal {
template <typename... Args>
class OnceCallbackHolder final {
public:
OnceCallbackHolder(OnceCallback<void(Args...)> callback,
bool ignore_extra_runs)
: callback_(std::move(callback)), ignore_extra_runs_(ignore_extra_runs) {
DCHECK(callback_);
}
OnceCallbackHolder(const OnceCallbackHolder&) = delete;
OnceCallbackHolder& operator=(const OnceCallbackHolder&) = delete;
void Run(Args... args) {
if (has_run_.exchange(true)) {
CHECK(ignore_extra_runs_) << "Both OnceCallbacks returned by "
"base::SplitOnceCallback() were run. "
"At most one of the pair should be run.";
return;
}
DCHECK(callback_);
std::move(callback_).Run(std::forward<Args>(args)...);
}
private:
volatile std::atomic_bool has_run_{false};
base::OnceCallback<void(Args...)> callback_;
const bool ignore_extra_runs_;
};
} // namespace internal
///
/// Wraps the given OnceCallback into a RepeatingCallback that relays its
/// invocation to the original OnceCallback on the first invocation. The
/// following invocations are just ignored.
///
/// Note that this deliberately subverts the Once/Repeating paradigm of
/// Callbacks but helps ease the migration from old-style Callbacks. Avoid if
/// possible; use if necessary for migration.
///
// TODO(tzik): Remove it. https://crbug.com/730593
template <typename... Args>
RepeatingCallback<void(Args...)> AdaptCallbackForRepeating(
OnceCallback<void(Args...)> callback) {
using Helper = internal::OnceCallbackHolder<Args...>;
return base::BindRepeating(
&Helper::Run, std::make_unique<Helper>(std::move(callback),
/*ignore_extra_runs=*/true));
}
///
/// Wraps the given OnceCallback and returns two OnceCallbacks with an identical
/// signature. On first invokation of either returned callbacks, the original
/// callback is invoked. Invoking the remaining callback results in a crash.
///
template <typename... Args>
std::pair<OnceCallback<void(Args...)>, OnceCallback<void(Args...)>>
SplitOnceCallback(OnceCallback<void(Args...)> callback) {
using Helper = internal::OnceCallbackHolder<Args...>;
auto wrapped_once = base::BindRepeating(
&Helper::Run, std::make_unique<Helper>(std::move(callback),
/*ignore_extra_runs=*/false));
return std::make_pair(wrapped_once, wrapped_once);
}
///
/// ScopedClosureRunner is akin to std::unique_ptr<> for Closures. It ensures
/// that the Closure is executed no matter how the current scope exits.
/// If you are looking for "ScopedCallback", "CallbackRunner", or
/// "CallbackScoper" this is the class you want.
///
class ScopedClosureRunner {
public:
ScopedClosureRunner();
explicit ScopedClosureRunner(OnceClosure closure);
ScopedClosureRunner(ScopedClosureRunner&& other);
// Runs the current closure if it's set, then replaces it with the closure
// from |other|. This is akin to how unique_ptr frees the contained pointer in
// its move assignment operator. If you need to explicitly avoid running any
// current closure, use ReplaceClosure().
ScopedClosureRunner& operator=(ScopedClosureRunner&& other);
~ScopedClosureRunner();
explicit operator bool() const { return !!closure_; }
// Calls the current closure and resets it, so it wont be called again.
void RunAndReset();
// Replaces closure with the new one releasing the old one without calling it.
void ReplaceClosure(OnceClosure closure);
// Releases the Closure without calling.
[[nodiscard]] OnceClosure Release();
private:
OnceClosure closure_;
};
///
/// Creates a null callback.
///
class NullCallback {
public:
template <typename R, typename... Args>
operator RepeatingCallback<R(Args...)>() const {
return RepeatingCallback<R(Args...)>();
}
template <typename R, typename... Args>
operator OnceCallback<R(Args...)>() const {
return OnceCallback<R(Args...)>();
}
};
///
/// Creates a callback that does nothing when called.
///
class DoNothing {
public:
template <typename... Args>
operator RepeatingCallback<void(Args...)>() const {
return Repeatedly<Args...>();
}
template <typename... Args>
operator OnceCallback<void(Args...)>() const {
return Once<Args...>();
}
// Explicit way of specifying a specific callback type when the compiler can't
// deduce it.
template <typename... Args>
static RepeatingCallback<void(Args...)> Repeatedly() {
return BindRepeating([](Args... args) {});
}
template <typename... Args>
static OnceCallback<void(Args...)> Once() {
return BindOnce([](Args... args) {});
}
};
///
/// Useful for creating a Closure that will delete a pointer when invoked. Only
/// use this when necessary. In most cases MessageLoop::DeleteSoon() is a better
/// fit.
///
template <typename T>
void DeletePointer(T* obj) {
delete obj;
}
} // namespace base
#endif // !USING_CHROMIUM_INCLUDES
#endif // CEF_INCLUDE_BASE_CEF_CALLBACK_HELPERS_H_