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
|
// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_THREADING_THREAD_CHECKER_IMPL_H_
#define BASE_THREADING_THREAD_CHECKER_IMPL_H_
#include <memory>
#include "base/base_export.h"
#include "base/sequence_token.h"
#include "base/synchronization/lock.h"
#include "base/thread_annotations.h"
#include "base/threading/platform_thread_ref.h"
namespace base {
namespace debug {
class StackTrace;
}
class SequenceCheckerImpl;
// Real implementation of ThreadChecker, for use in debug mode, or for temporary
// use in release mode (e.g. to CHECK on a threading issue seen only in the
// wild).
//
// Note: You should almost always use the ThreadChecker class to get the right
// version for your build configuration.
// Note: This is only a check, not a "lock". It is marked "LOCKABLE" only in
// order to support thread_annotations.h.
class LOCKABLE BASE_EXPORT ThreadCheckerImpl {
public:
static void EnableStackLogging();
ThreadCheckerImpl();
~ThreadCheckerImpl();
// Allow move construct/assign. This must be called on |other|'s associated
// thread and assignment can only be made into a ThreadCheckerImpl which is
// detached or already associated with the current thread. This isn't
// thread-safe (|this| and |other| shouldn't be in use while this move is
// performed). If the assignment was legal, the resulting ThreadCheckerImpl
// will be bound to the current thread and |other| will be detached.
ThreadCheckerImpl(ThreadCheckerImpl&& other);
ThreadCheckerImpl& operator=(ThreadCheckerImpl&& other);
// On returning false, if logging is enabled with EnableStackLogging() and
// `out_bound_at` is not null, this method allocates a StackTrace and returns
// it in the out-parameter, storing inside it the stack from where the failing
// ThreadChecker was bound to its thread.
[[nodiscard]] bool CalledOnValidThread(
std::unique_ptr<debug::StackTrace>* out_bound_at = nullptr) const
LOCKS_EXCLUDED(lock_);
// Changes the thread that is checked for in CalledOnValidThread. This may
// be useful when an object may be created on one thread and then used
// exclusively on another thread.
void DetachFromThread() LOCKS_EXCLUDED(lock_);
private:
// This shares storage with SequenceCheckerImpl.
friend class SequenceCheckerImpl;
[[nodiscard]] bool CalledOnValidThreadInternal(
std::unique_ptr<debug::StackTrace>* out_bound_at) const
EXCLUSIVE_LOCKS_REQUIRED(lock_);
// Returns ownership of a pointer to StackTrace where the ThreadCheckerImpl
// was bound for debug logs, or nullptr if such logging was not enabled at
// the time.
std::unique_ptr<debug::StackTrace> GetBoundAt() const
EXCLUSIVE_LOCKS_REQUIRED(lock_);
void EnsureAssigned() const EXCLUSIVE_LOCKS_REQUIRED(lock_);
// Members are mutable so that CalledOnValidThread() can set them.
// Synchronizes access to all members.
mutable base::Lock lock_;
// The location where the ThreadChecker was bound to the current
// thread/task/sequence. Default-initialized with 0 frames until bound.
mutable std::unique_ptr<debug::StackTrace> bound_at_ GUARDED_BY(lock_);
// Thread on which CalledOnValidThread() may return true.
mutable PlatformThreadRef thread_id_ GUARDED_BY(lock_);
// TaskToken for which CalledOnValidThread() always returns true. This allows
// CalledOnValidThread() to return true when called multiple times from the
// same task, even if it's not running in a single-threaded context itself
// (allowing usage of ThreadChecker objects on the stack in the scope of one-
// off tasks). Note: CalledOnValidThread() may return true even if the current
// TaskToken is not equal to this.
mutable TaskToken task_token_ GUARDED_BY(lock_);
// SequenceToken for which CalledOnValidThread() may return true. Used to
// ensure that CalledOnValidThread() doesn't return true for ThreadPool
// tasks that happen to run on the same thread but weren't posted to the same
// SingleThreadTaskRunner.
//
// Also used for SequenceCheckerImpl's CalledOnValidSequence(), as this shares
// storage. See SequenceCheckerImpl.
mutable SequenceToken sequence_token_ GUARDED_BY(lock_);
};
} // namespace base
#endif // BASE_THREADING_THREAD_CHECKER_IMPL_H_
|
