blob: 66534dedeab0785d5bcddf304faabbe9b5dc3c21 [file] [log] [blame]
/*
* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "webrtc/modules/utility/source/process_thread_impl.h"
#include "webrtc/base/checks.h"
#include "webrtc/base/task_queue.h"
#include "webrtc/base/timeutils.h"
#include "webrtc/modules/include/module.h"
#include "webrtc/system_wrappers/include/logging.h"
namespace webrtc {
namespace {
// We use this constant internally to signal that a module has requested
// a callback right away. When this is set, no call to TimeUntilNextProcess
// should be made, but Process() should be called directly.
const int64_t kCallProcessImmediately = -1;
int64_t GetNextCallbackTime(Module* module, int64_t time_now) {
int64_t interval = module->TimeUntilNextProcess();
if (interval < 0) {
// Falling behind, we should call the callback now.
return time_now;
}
return time_now + interval;
}
}
ProcessThread::~ProcessThread() {}
// static
std::unique_ptr<ProcessThread> ProcessThread::Create(
const char* thread_name) {
return std::unique_ptr<ProcessThread>(new ProcessThreadImpl(thread_name));
}
ProcessThreadImpl::ProcessThreadImpl(const char* thread_name)
: wake_up_(EventWrapper::Create()),
stop_(false),
thread_name_(thread_name) {}
ProcessThreadImpl::~ProcessThreadImpl() {
RTC_DCHECK(thread_checker_.CalledOnValidThread());
RTC_DCHECK(!thread_.get());
RTC_DCHECK(!stop_);
while (!queue_.empty()) {
delete queue_.front();
queue_.pop();
}
}
void ProcessThreadImpl::Start() {
RTC_DCHECK(thread_checker_.CalledOnValidThread());
RTC_DCHECK(!thread_.get());
if (thread_.get())
return;
RTC_DCHECK(!stop_);
{
// TODO(tommi): Since DeRegisterModule is currently being called from
// different threads in some cases (ChannelOwner), we need to lock access to
// the modules_ collection even on the controller thread.
// Once we've cleaned up those places, we can remove this lock.
rtc::CritScope lock(&lock_);
for (ModuleCallback& m : modules_)
m.module->ProcessThreadAttached(this);
}
thread_.reset(
new rtc::PlatformThread(&ProcessThreadImpl::Run, this, thread_name_));
thread_->Start();
}
void ProcessThreadImpl::Stop() {
RTC_DCHECK(thread_checker_.CalledOnValidThread());
if(!thread_.get())
return;
{
rtc::CritScope lock(&lock_);
stop_ = true;
}
wake_up_->Set();
thread_->Stop();
stop_ = false;
// TODO(tommi): Since DeRegisterModule is currently being called from
// different threads in some cases (ChannelOwner), we need to lock access to
// the modules_ collection even on the controller thread.
// Since DeRegisterModule also checks thread_, we also need to hold the
// lock for the .reset() operation.
// Once we've cleaned up those places, we can remove this lock.
rtc::CritScope lock(&lock_);
thread_.reset();
for (ModuleCallback& m : modules_)
m.module->ProcessThreadAttached(nullptr);
}
void ProcessThreadImpl::WakeUp(Module* module) {
// Allowed to be called on any thread.
{
rtc::CritScope lock(&lock_);
for (ModuleCallback& m : modules_) {
if (m.module == module)
m.next_callback = kCallProcessImmediately;
}
}
wake_up_->Set();
}
void ProcessThreadImpl::PostTask(std::unique_ptr<rtc::QueuedTask> task) {
// Allowed to be called on any thread.
{
rtc::CritScope lock(&lock_);
queue_.push(task.release());
}
wake_up_->Set();
}
void ProcessThreadImpl::RegisterModule(Module* module) {
RTC_DCHECK(thread_checker_.CalledOnValidThread());
RTC_DCHECK(module);
#if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON))
{
// Catch programmer error.
rtc::CritScope lock(&lock_);
for (const ModuleCallback& mc : modules_)
RTC_DCHECK(mc.module != module);
}
#endif
// Now that we know the module isn't in the list, we'll call out to notify
// the module that it's attached to the worker thread. We don't hold
// the lock while we make this call.
if (thread_.get())
module->ProcessThreadAttached(this);
{
rtc::CritScope lock(&lock_);
modules_.push_back(ModuleCallback(module));
}
// Wake the thread calling ProcessThreadImpl::Process() to update the
// waiting time. The waiting time for the just registered module may be
// shorter than all other registered modules.
wake_up_->Set();
}
void ProcessThreadImpl::DeRegisterModule(Module* module) {
// Allowed to be called on any thread.
// TODO(tommi): Disallow this ^^^
RTC_DCHECK(module);
{
rtc::CritScope lock(&lock_);
modules_.remove_if([&module](const ModuleCallback& m) {
return m.module == module;
});
// TODO(tommi): we currently need to hold the lock while calling out to
// ProcessThreadAttached. This is to make sure that the thread hasn't been
// destroyed while we attach the module. Once we can make sure
// DeRegisterModule isn't being called on arbitrary threads, we can move the
// |if (thread_.get())| check and ProcessThreadAttached() call outside the
// lock scope.
// Notify the module that it's been detached.
if (thread_.get())
module->ProcessThreadAttached(nullptr);
}
}
// static
bool ProcessThreadImpl::Run(void* obj) {
return static_cast<ProcessThreadImpl*>(obj)->Process();
}
bool ProcessThreadImpl::Process() {
int64_t now = rtc::TimeMillis();
int64_t next_checkpoint = now + (1000 * 60);
{
rtc::CritScope lock(&lock_);
if (stop_)
return false;
for (ModuleCallback& m : modules_) {
// TODO(tommi): Would be good to measure the time TimeUntilNextProcess
// takes and dcheck if it takes too long (e.g. >=10ms). Ideally this
// operation should not require taking a lock, so querying all modules
// should run in a matter of nanoseconds.
if (m.next_callback == 0)
m.next_callback = GetNextCallbackTime(m.module, now);
if (m.next_callback <= now ||
m.next_callback == kCallProcessImmediately) {
m.module->Process();
// Use a new 'now' reference to calculate when the next callback
// should occur. We'll continue to use 'now' above for the baseline
// of calculating how long we should wait, to reduce variance.
int64_t new_now = rtc::TimeMillis();
m.next_callback = GetNextCallbackTime(m.module, new_now);
}
if (m.next_callback < next_checkpoint)
next_checkpoint = m.next_callback;
}
while (!queue_.empty()) {
rtc::QueuedTask* task = queue_.front();
queue_.pop();
lock_.Leave();
task->Run();
delete task;
lock_.Enter();
}
}
int64_t time_to_wait = next_checkpoint - rtc::TimeMillis();
if (time_to_wait > 0)
wake_up_->Wait(static_cast<unsigned long>(time_to_wait));
return true;
}
} // namespace webrtc