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// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/threading/simple_thread.h"
#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/threading/platform_thread.h"
#include "base/threading/thread_restrictions.h"
namespace base {
SimpleThread::SimpleThread(const std::string& name_prefix)
: SimpleThread(name_prefix, Options()) {}
SimpleThread::SimpleThread(const std::string& name_prefix,
const Options& options)
: name_prefix_(name_prefix),
options_(options),
event_(WaitableEvent::ResetPolicy::MANUAL,
WaitableEvent::InitialState::NOT_SIGNALED) {}
SimpleThread::~SimpleThread() {
DCHECK(HasBeenStarted()) << "SimpleThread was never started.";
DCHECK(!options_.joinable || HasBeenJoined())
<< "Joinable SimpleThread destroyed without being Join()ed.";
}
void SimpleThread::Start() {
DCHECK(!HasBeenStarted()) << "Tried to Start a thread multiple times.";
bool success =
options_.joinable
? PlatformThread::CreateWithPriority(options_.stack_size, this,
&thread_, options_.priority)
: PlatformThread::CreateNonJoinableWithPriority(
options_.stack_size, this, options_.priority);
DCHECK(success);
ThreadRestrictions::ScopedAllowWait allow_wait;
event_.Wait(); // Wait for the thread to complete initialization.
}
void SimpleThread::Join() {
DCHECK(options_.joinable) << "A non-joinable thread can't be joined.";
DCHECK(HasBeenStarted()) << "Tried to Join a never-started thread.";
DCHECK(!HasBeenJoined()) << "Tried to Join a thread multiple times.";
PlatformThread::Join(thread_);
thread_ = PlatformThreadHandle();
joined_ = true;
}
bool SimpleThread::HasBeenStarted() {
ThreadRestrictions::ScopedAllowWait allow_wait;
return event_.IsSignaled();
}
void SimpleThread::ThreadMain() {
tid_ = PlatformThread::CurrentId();
// Construct our full name of the form "name_prefix_/TID".
std::string name(name_prefix_);
name.push_back('/');
name.append(IntToString(tid_));
PlatformThread::SetName(name);
// We've initialized our new thread, signal that we're done to Start().
event_.Signal();
Run();
}
DelegateSimpleThread::DelegateSimpleThread(Delegate* delegate,
const std::string& name_prefix)
: DelegateSimpleThread(delegate, name_prefix, Options()) {}
DelegateSimpleThread::DelegateSimpleThread(Delegate* delegate,
const std::string& name_prefix,
const Options& options)
: SimpleThread(name_prefix, options),
delegate_(delegate) {
DCHECK(delegate_);
}
DelegateSimpleThread::~DelegateSimpleThread() = default;
void DelegateSimpleThread::Run() {
DCHECK(delegate_) << "Tried to call Run without a delegate (called twice?)";
// Non-joinable DelegateSimpleThreads are allowed to be deleted during Run().
// Member state must not be accessed after invoking Run().
Delegate* delegate = delegate_;
delegate_ = nullptr;
delegate->Run();
}
DelegateSimpleThreadPool::DelegateSimpleThreadPool(
const std::string& name_prefix,
int num_threads)
: name_prefix_(name_prefix),
num_threads_(num_threads),
dry_(WaitableEvent::ResetPolicy::MANUAL,
WaitableEvent::InitialState::NOT_SIGNALED) {}
DelegateSimpleThreadPool::~DelegateSimpleThreadPool() {
DCHECK(threads_.empty());
DCHECK(delegates_.empty());
DCHECK(!dry_.IsSignaled());
}
void DelegateSimpleThreadPool::Start() {
DCHECK(threads_.empty()) << "Start() called with outstanding threads.";
for (int i = 0; i < num_threads_; ++i) {
DelegateSimpleThread* thread = new DelegateSimpleThread(this, name_prefix_);
thread->Start();
threads_.push_back(thread);
}
}
void DelegateSimpleThreadPool::JoinAll() {
DCHECK(!threads_.empty()) << "JoinAll() called with no outstanding threads.";
// Tell all our threads to quit their worker loop.
AddWork(NULL, num_threads_);
// Join and destroy all the worker threads.
for (int i = 0; i < num_threads_; ++i) {
threads_[i]->Join();
delete threads_[i];
}
threads_.clear();
DCHECK(delegates_.empty());
}
void DelegateSimpleThreadPool::AddWork(Delegate* delegate, int repeat_count) {
AutoLock locked(lock_);
for (int i = 0; i < repeat_count; ++i)
delegates_.push(delegate);
// If we were empty, signal that we have work now.
if (!dry_.IsSignaled())
dry_.Signal();
}
void DelegateSimpleThreadPool::Run() {
Delegate* work = NULL;
while (true) {
dry_.Wait();
{
AutoLock locked(lock_);
if (!dry_.IsSignaled())
continue;
DCHECK(!delegates_.empty());
work = delegates_.front();
delegates_.pop();
// Signal to any other threads that we're currently out of work.
if (delegates_.empty())
dry_.Reset();
}
// A NULL delegate pointer signals us to quit.
if (!work)
break;
work->Run();
}
}
} // namespace base
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