current_thread.h | Explore in Territory

// Copyright 2018 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_TASK_CURRENT_THREAD_H_
#define BASE_TASK_CURRENT_THREAD_H_

#include <ostream>
#include <type_traits>

#include "base/base_export.h"
#include "base/callback_list.h"
#include "base/check.h"
#include "base/functional/callback_forward.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/scoped_refptr.h"
#include "base/message_loop/ios_cronet_buildflags.h"
#include "base/message_loop/message_pump_for_io.h"
#include "base/message_loop/message_pump_for_ui.h"
#include "base/pending_task.h"
#include "base/task/sequence_manager/task_time_observer.h"
#include "base/task/single_thread_task_runner.h"
#include "base/task/task_observer.h"
#include "build/build_config.h"

namespace autofill {
class NextIdleBarrier;
}

namespace content {
class BrowserMainLoop;
}

namespace web {
class WebTaskEnvironment;
}

namespace base {

namespace test {
bool RunUntil(FunctionRef<bool(void)>);
void TestPredicateOrRegisterOnNextIdleCallback(base::FunctionRef<bool(void)>,
                                               CallbackListSubscription*,
                                               OnceClosure);
}  // namespace test

namespace sequence_manager {
namespace internal {
class SequenceManagerImpl;
}
}  // namespace sequence_manager

// CurrentThread is a proxy to a subset of Task related APIs bound to the
// current thread
//
// Current(UI|IO)Thread is available statically through
// Current(UI|IO)Thread::Get() on threads that have registered as CurrentThread
// on this physical thread (e.g. by using SingleThreadTaskExecutor). APIs
// intended for all consumers on the thread should be on Current(UI|IO)Thread,
// while internal APIs might be on multiple internal classes (e.g.
// SequenceManager).
//
// Why: Historically MessageLoop would take care of everything related to event
// processing on a given thread. Nowadays that functionality is split among
// different classes. At that time MessageLoop::current() gave access to the
// full MessageLoop API, preventing both addition of powerful owner-only APIs as
// well as making it harder to remove callers of deprecated APIs (that need to
// stick around for a few owner-only use cases and re-accrue callers after
// cleanup per remaining publicly available).
//
// As such, many methods below are flagged as deprecated and should be removed
// once all static callers have been migrated.
class BASE_EXPORT CurrentThread { … };

#if !BUILDFLAG(IS_NACL)

// UI extension of CurrentThread.
class BASE_EXPORT CurrentUIThread : public CurrentThread { … };

#endif  // !BUILDFLAG(IS_NACL)

// ForIO extension of CurrentThread.
class BASE_EXPORT CurrentIOThread : public CurrentThread { … };

}  // namespace base

#endif  // BASE_TASK_CURRENT_THREAD_H_
chromium/base/task/current_thread.h
