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Refactor the PlatformThread API.

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PlatformThread's API is using old style function pointers, causes
casting, is unintuitive and forces artificial call sequences, and
is additionally possible to misuse in release mode.

Fix this by an API face lift:
1. The class is turned into a handle, which can be empty.
2. The only way of getting a non-empty PlatformThread is by calling
SpawnJoinable or SpawnDetached, clearly conveying the semantics to the
code reader.
3. Handles can be Finalized, which works differently for joinable and
detached threads:
  a) Handles for detached threads are simply closed where applicable.
  b) Joinable threads are joined before handles are closed.
4. The destructor finalizes handles. No explicit call is needed.

Fixed: webrtc:12727
Change-Id: Id00a0464edf4fc9e552b6a1fbb5d2e1280e88811
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/215075
Commit-Queue: Markus Handell <handellm@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33923}
This commit is contained in:
Markus Handell
2021-05-05 10:42:04 +02:00
committed by WebRTC LUCI CQ
parent 1c5c2178fe
commit c89fdd716c
38 changed files with 586 additions and 864 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
modules/utility/source/process_thread_impl.cc
View File

@ -48,7 +48,6 @@ ProcessThreadImpl::ProcessThreadImpl(const char* thread_name)
ProcessThreadImpl::~ProcessThreadImpl() {
RTC_DCHECK(thread_checker_.IsCurrent());
RTC_DCHECK(!thread_.get());
RTC_DCHECK(!stop_);
while (!delayed_tasks_.empty()) {
@ -72,8 +71,8 @@ void ProcessThreadImpl::Delete() {
// Doesn't need locking, because the contending thread isn't running.
void ProcessThreadImpl::Start() RTC_NO_THREAD_SAFETY_ANALYSIS {
RTC_DCHECK(thread_checker_.IsCurrent());
RTC_DCHECK(!thread_.get());
if (thread_.get())
RTC_DCHECK(thread_.empty());
if (!thread_.empty())
return;
RTC_DCHECK(!stop_);
@ -81,14 +80,18 @@ void ProcessThreadImpl::Start() RTC_NO_THREAD_SAFETY_ANALYSIS {
for (ModuleCallback& m : modules_)
m.module->ProcessThreadAttached(this);
thread_.reset(
new rtc::PlatformThread(&ProcessThreadImpl::Run, this, thread_name_));
thread_->Start();
thread_ = rtc::PlatformThread::SpawnJoinable(
[this] {
CurrentTaskQueueSetter set_current(this);
while (Process()) {
}
},
thread_name_);
}
void ProcessThreadImpl::Stop() {
RTC_DCHECK(thread_checker_.IsCurrent());
if (!thread_.get())
if (thread_.empty())
return;
{
@ -98,9 +101,7 @@ void ProcessThreadImpl::Stop() {
}
wake_up_.Set();
thread_->Stop();
thread_.reset();
thread_.Finalize();
StopNoLocks();
}
@ -108,7 +109,7 @@ void ProcessThreadImpl::Stop() {
// No locking needed, since this is called after the contending thread is
// stopped.
void ProcessThreadImpl::StopNoLocks() RTC_NO_THREAD_SAFETY_ANALYSIS {
RTC_DCHECK(!thread_);
RTC_DCHECK(thread_.empty());
stop_ = false;
for (ModuleCallback& m : modules_)
@ -199,7 +200,7 @@ void ProcessThreadImpl::RegisterModule(Module* module,
// 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())
if (!thread_.empty())
module->ProcessThreadAttached(this);
{
@ -227,14 +228,6 @@ void ProcessThreadImpl::DeRegisterModule(Module* module) {
module->ProcessThreadAttached(nullptr);
}
// static
void ProcessThreadImpl::Run(void* obj) {
ProcessThreadImpl* impl = static_cast<ProcessThreadImpl*>(obj);
CurrentTaskQueueSetter set_current(impl);
while (impl->Process()) {
}
}
bool ProcessThreadImpl::Process() {
TRACE_EVENT1("webrtc", "ProcessThreadImpl", "name", thread_name_);
int64_t now = rtc::TimeMillis();