forked from cztomczak/cefpython
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathcef_bind.h
More file actions
390 lines (362 loc) · 13.8 KB
/
cef_bind.h
File metadata and controls
390 lines (362 loc) · 13.8 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
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
// 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.
///
/// \file
/// base::BindOnce() and base::BindRepeating() are helpers for creating
/// base::OnceCallback and base::RepeatingCallback objects respectively.
///
/// For a runnable object of n-arity, the base::Bind*() family allows partial
/// application of the first m arguments. The remaining n - m arguments must be
/// passed when invoking the callback with Run().
///
/// <pre>
/// // The first argument is bound at callback creation; the remaining
/// // two must be passed when calling Run() on the callback object.
/// base::OnceCallback<long(int, long)> cb = base::BindOnce(
/// [](short x, int y, long z) { return x * y * z; }, 42);
/// </pre>
///
/// When binding to a method, the receiver object must also be specified at
/// callback creation time. When Run() is invoked, the method will be invoked on
/// the specified receiver object.
///
/// <pre>
/// class C : public base::RefCounted<C> { void F(); };
/// auto instance = base::MakeRefCounted<C>();
/// auto cb = base::BindOnce(&C::F, instance);
/// std::move(cb).Run(); // Identical to instance->F()
/// </pre>
///
/// See https://chromium.googlesource.com/chromium/src/+/lkgr/docs/callback.md
/// for the full documentation.
///
// Implementation notes
//
// If you're reading the implementation, before proceeding further, you should
// read the top comment of base/internal/cef_bind_internal.h for a definition
// of common terms and concepts.
#ifndef CEF_INCLUDE_BASE_CEF_BIND_H_
#define CEF_INCLUDE_BASE_CEF_BIND_H_
#pragma once
#if defined(USING_CHROMIUM_INCLUDES)
// When building CEF include the Chromium header directly.
#include "base/functional/bind.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 <functional>
#include <memory>
#include <type_traits>
#include <utility>
#include "include/base/cef_build.h"
#include "include/base/cef_compiler_specific.h"
#include "include/base/internal/cef_bind_internal.h"
#if defined(OS_APPLE) && !HAS_FEATURE(objc_arc)
#include "include/base/internal/cef_scoped_block_mac.h"
#endif
namespace base {
///
/// Bind as OnceCallback.
///
template <typename Functor, typename... Args>
inline OnceCallback<cef_internal::MakeUnboundRunType<Functor, Args...>>
BindOnce(Functor&& functor, Args&&... args) {
static_assert(!cef_internal::IsOnceCallback<std::decay_t<Functor>>() ||
(std::is_rvalue_reference<Functor&&>() &&
!std::is_const<std::remove_reference_t<Functor>>()),
"BindOnce requires non-const rvalue for OnceCallback binding."
" I.e.: base::BindOnce(std::move(callback)).");
static_assert(
std::conjunction<cef_internal::AssertBindArgIsNotBasePassed<
std::decay_t<Args>>...>::value,
"Use std::move() instead of base::Passed() with base::BindOnce()");
return cef_internal::BindImpl<OnceCallback>(std::forward<Functor>(functor),
std::forward<Args>(args)...);
}
///
/// Bind as RepeatingCallback.
///
template <typename Functor, typename... Args>
inline RepeatingCallback<cef_internal::MakeUnboundRunType<Functor, Args...>>
BindRepeating(Functor&& functor, Args&&... args) {
static_assert(
!cef_internal::IsOnceCallback<std::decay_t<Functor>>(),
"BindRepeating cannot bind OnceCallback. Use BindOnce with std::move().");
return cef_internal::BindImpl<RepeatingCallback>(
std::forward<Functor>(functor), std::forward<Args>(args)...);
}
///
/// Special cases for binding to a base::Callback without extra bound arguments.
/// We CHECK() the validity of callback to guard against null pointers
/// accidentally ending up in posted tasks, causing hard-to-debug crashes.
///
template <typename Signature>
OnceCallback<Signature> BindOnce(OnceCallback<Signature> callback) {
CHECK(callback);
return callback;
}
template <typename Signature>
OnceCallback<Signature> BindOnce(RepeatingCallback<Signature> callback) {
CHECK(callback);
return callback;
}
template <typename Signature>
RepeatingCallback<Signature> BindRepeating(
RepeatingCallback<Signature> callback) {
CHECK(callback);
return callback;
}
///
/// Unretained() allows binding a non-refcounted class, and to disable
/// refcounting on arguments that are refcounted objects.
///
/// EXAMPLE OF Unretained():
///
/// <pre>
/// class Foo {
/// public:
/// void func() { cout << "Foo:f" << endl; }
/// };
///
/// // In some function somewhere.
/// Foo foo;
/// OnceClosure foo_callback =
/// BindOnce(&Foo::func, Unretained(&foo));
/// std::move(foo_callback).Run(); // Prints "Foo:f".
/// </pre>
///
/// Without the Unretained() wrapper on |&foo|, the above call would fail
/// to compile because Foo does not support the AddRef() and Release() methods.
///
template <typename T>
inline cef_internal::UnretainedWrapper<T> Unretained(T* o) {
return cef_internal::UnretainedWrapper<T>(o);
}
///
/// RetainedRef() accepts a ref counted object and retains a reference to it.
/// When the callback is called, the object is passed as a raw pointer.
///
/// EXAMPLE OF RetainedRef():
///
/// <pre>
/// void foo(RefCountedBytes* bytes) {}
///
/// scoped_refptr<RefCountedBytes> bytes = ...;
/// OnceClosure callback = BindOnce(&foo, base::RetainedRef(bytes));
/// std::move(callback).Run();
/// </pre>
///
/// Without RetainedRef, the scoped_refptr would try to implicitly convert to
/// a raw pointer and fail compilation:
///
/// <pre>
/// OnceClosure callback = BindOnce(&foo, bytes); // ERROR!
/// </pre>
///
template <typename T>
inline cef_internal::RetainedRefWrapper<T> RetainedRef(T* o) {
return cef_internal::RetainedRefWrapper<T>(o);
}
template <typename T>
inline cef_internal::RetainedRefWrapper<T> RetainedRef(scoped_refptr<T> o) {
return cef_internal::RetainedRefWrapper<T>(std::move(o));
}
///
/// Owned() transfers ownership of an object to the callback resulting from
/// bind; the object will be deleted when the callback is deleted.
///
/// EXAMPLE OF Owned():
///
/// <pre>
/// void foo(int* arg) { cout << *arg << endl }
///
/// int* pn = new int(1);
/// RepeatingClosure foo_callback = BindRepeating(&foo, Owned(pn));
///
/// foo_callback.Run(); // Prints "1"
/// foo_callback.Run(); // Prints "1"
/// *pn = 2;
/// foo_callback.Run(); // Prints "2"
///
/// foo_callback.Reset(); // |pn| is deleted. Also will happen when
/// // |foo_callback| goes out of scope.
/// </pre>
///
/// Without Owned(), someone would have to know to delete |pn| when the last
/// reference to the callback is deleted.
///
template <typename T>
inline cef_internal::OwnedWrapper<T> Owned(T* o) {
return cef_internal::OwnedWrapper<T>(o);
}
template <typename T, typename Deleter>
inline cef_internal::OwnedWrapper<T, Deleter> Owned(
std::unique_ptr<T, Deleter>&& ptr) {
return cef_internal::OwnedWrapper<T, Deleter>(std::move(ptr));
}
///
/// OwnedRef() stores an object in the callback resulting from
/// bind and passes a reference to the object to the bound function.
///
/// EXAMPLE OF OwnedRef():
///
/// <pre>
/// void foo(int& arg) { cout << ++arg << endl }
///
/// int counter = 0;
/// RepeatingClosure foo_callback = BindRepeating(&foo, OwnedRef(counter));
///
/// foo_callback.Run(); // Prints "1"
/// foo_callback.Run(); // Prints "2"
/// foo_callback.Run(); // Prints "3"
///
/// cout << counter; // Prints "0", OwnedRef creates a copy of counter.
/// </pre>
///
/// Supports OnceCallbacks as well, useful to pass placeholder arguments:
///
/// <pre>
/// void bar(int& ignore, const std::string& s) { cout << s << endl }
///
/// OnceClosure bar_callback = BindOnce(&bar, OwnedRef(0), "Hello");
///
/// std::move(bar_callback).Run(); // Prints "Hello"
/// </pre>
///
/// Without OwnedRef() it would not be possible to pass a mutable reference to
/// an object owned by the callback.
///
template <typename T>
cef_internal::OwnedRefWrapper<std::decay_t<T>> OwnedRef(T&& t) {
return cef_internal::OwnedRefWrapper<std::decay_t<T>>(std::forward<T>(t));
}
///
/// Passed() is for transferring movable-but-not-copyable types (eg. unique_ptr)
/// through a RepeatingCallback. Logically, this signifies a destructive
/// transfer of the state of the argument into the target function. Invoking
/// RepeatingCallback::Run() twice on a callback that was created with a
/// Passed() argument will CHECK() because the first invocation would have
/// already transferred ownership to the target function.
///
/// Note that Passed() is not necessary with BindOnce(), as std::move() does the
/// same thing. Avoid Passed() in favor of std::move() with BindOnce().
///
/// EXAMPLE OF Passed():
///
/// <pre>
/// void TakesOwnership(std::unique_ptr<Foo> arg) { }
/// std::unique_ptr<Foo> CreateFoo() { return std::make_unique<Foo>();
/// }
///
/// auto f = std::make_unique<Foo>();
///
/// // |cb| is given ownership of Foo(). |f| is now NULL.
/// // You can use std::move(f) in place of &f, but it's more verbose.
/// RepeatingClosure cb = BindRepeating(&TakesOwnership, Passed(&f));
///
/// // Run was never called so |cb| still owns Foo() and deletes
/// // it on Reset().
/// cb.Reset();
///
/// // |cb| is given a new Foo created by CreateFoo().
/// cb = BindRepeating(&TakesOwnership, Passed(CreateFoo()));
///
/// // |arg| in TakesOwnership() is given ownership of Foo(). |cb|
/// // no longer owns Foo() and, if reset, would not delete Foo().
/// cb.Run(); // Foo() is now transferred to |arg| and deleted.
/// cb.Run(); // This CHECK()s since Foo() already been used once.
/// </pre>
///
/// We offer 2 syntaxes for calling Passed(). The first takes an rvalue and is
/// best suited for use with the return value of a function or other temporary
/// rvalues. The second takes a pointer to the scoper and is just syntactic
/// sugar to avoid having to write Passed(std::move(scoper)).
///
/// Both versions of Passed() prevent T from being an lvalue reference. The
/// first via use of enable_if, and the second takes a T* which will not bind to
/// T&.
///
template <typename T,
std::enable_if_t<!std::is_lvalue_reference<T>::value>* = nullptr>
inline cef_internal::PassedWrapper<T> Passed(T&& scoper) {
return cef_internal::PassedWrapper<T>(std::move(scoper));
}
template <typename T>
inline cef_internal::PassedWrapper<T> Passed(T* scoper) {
return cef_internal::PassedWrapper<T>(std::move(*scoper));
}
///
/// IgnoreResult() is used to adapt a function or callback with a return type to
/// one with a void return. This is most useful if you have a function with,
/// say, a pesky ignorable bool return that you want to use with PostTask or
/// something else that expect a callback with a void return.
///
/// EXAMPLE OF IgnoreResult():
///
/// <pre>
/// int DoSomething(int arg) { cout << arg << endl; }
///
/// // Assign to a callback with a void return type.
/// OnceCallback<void(int)> cb = BindOnce(IgnoreResult(&DoSomething));
/// std::move(cb).Run(1); // Prints "1".
///
/// // Prints "2" on |ml|.
/// ml->PostTask(FROM_HERE, BindOnce(IgnoreResult(&DoSomething), 2);
/// </pre>
///
template <typename T>
inline cef_internal::IgnoreResultHelper<T> IgnoreResult(T data) {
return cef_internal::IgnoreResultHelper<T>(std::move(data));
}
#if defined(OS_APPLE) && !HAS_FEATURE(objc_arc)
///
/// RetainBlock() is used to adapt an Objective-C block when Automated Reference
/// Counting (ARC) is disabled. This is unnecessary when ARC is enabled, as the
/// BindOnce and BindRepeating already support blocks then.
///
/// EXAMPLE OF RetainBlock():
///
/// <pre>
/// // Wrap the block and bind it to a callback.
/// OnceCallback<void(int)> cb =
/// BindOnce(RetainBlock(^(int n) { NSLog(@"%d", n); }));
/// std::move(cb).Run(1); // Logs "1".
/// </pre>
///
template <typename R, typename... Args>
base::mac::ScopedBlock<R (^)(Args...)> RetainBlock(R (^block)(Args...)) {
return base::mac::ScopedBlock<R (^)(Args...)>(block,
base::scoped_policy::RETAIN);
}
#endif // defined(OS_APPLE) && !HAS_FEATURE(objc_arc)
} // namespace base
#endif // !USING_CHROMIUM_INCLUDES
#endif // CEF_INCLUDE_BASE_CEF_BIND_H_