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Remove rtc::GlobalLock.

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This change migrates a last stray consumer of GlobalLock
(SrtpSession) and removes all traces of GlobalLock/GlobalLockScope
from WebRTC.

Bug: webrtc:11567
Change-Id: I28059f2a10075815a4bdee8c357b9d3b6e50f18b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/179361
Commit-Queue: Tommi <tommi@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31736}
This commit is contained in:
Markus Handell 2020-07-15 13:23:30 +02:00 committed by Commit Bot
parent e7e17d3e4c
commit 4c7bb27a10
5 changed files with 7 additions and 68 deletions
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9
pc/srtp_session.cc
View File

@ -13,7 +13,6 @@
#include "absl/base/attributes.h"
#include "media/base/rtp_utils.h"
#include "pc/external_hmac.h"
#include "rtc_base/critical_section.h"
#include "rtc_base/logging.h"
#include "rtc_base/ssl_stream_adapter.h"
#include "system_wrappers/include/metrics.h"
@ -364,16 +363,16 @@ bool SrtpSession::UpdateKey(int type,
}
ABSL_CONST_INIT int g_libsrtp_usage_count = 0;
ABSL_CONST_INIT rtc::GlobalLock g_libsrtp_lock;
ABSL_CONST_INIT webrtc::GlobalMutex g_libsrtp_lock(absl::kConstInit);
void ProhibitLibsrtpInitialization() {
rtc::GlobalLockScope ls(&g_libsrtp_lock);
webrtc::GlobalMutexLock ls(&g_libsrtp_lock);
++g_libsrtp_usage_count;
}
// static
bool SrtpSession::IncrementLibsrtpUsageCountAndMaybeInit() {
rtc::GlobalLockScope ls(&g_libsrtp_lock);
webrtc::GlobalMutexLock ls(&g_libsrtp_lock);
RTC_DCHECK_GE(g_libsrtp_usage_count, 0);
if (g_libsrtp_usage_count == 0) {
@ -402,7 +401,7 @@ bool SrtpSession::IncrementLibsrtpUsageCountAndMaybeInit() {
// static
void SrtpSession::DecrementLibsrtpUsageCountAndMaybeDeinit() {
rtc::GlobalLockScope ls(&g_libsrtp_lock);
webrtc::GlobalMutexLock ls(&g_libsrtp_lock);
RTC_DCHECK_GE(g_libsrtp_usage_count, 1);
if (--g_libsrtp_usage_count == 0) {

5
pc/srtp_session.h
View File

@ -14,7 +14,8 @@
#include <vector>
#include "api/scoped_refptr.h"
#include "rtc_base/critical_section.h"
#include "rtc_base/constructor_magic.h"
#include "rtc_base/synchronization/mutex.h"
#include "rtc_base/thread_checker.h"
// Forward declaration to avoid pulling in libsrtp headers here
@ -124,7 +125,7 @@ class SrtpSession {
int rtp_auth_tag_len_ = 0;
int rtcp_auth_tag_len_ = 0;
bool inited_ = false;
static rtc::GlobalLock lock_;
static webrtc::GlobalMutex lock_;
int last_send_seq_num_ = -1;
bool external_auth_active_ = false;
bool external_auth_enabled_ = false;

19
rtc_base/critical_section.cc
View File

@ -217,23 +217,4 @@ CritScope::~CritScope() {
cs_->Leave();
}
void GlobalLock::Lock() {
while (AtomicOps::CompareAndSwap(&lock_acquired_, 0, 1)) {
webrtc::YieldCurrentThread();
}
}
void GlobalLock::Unlock() {
int old_value = AtomicOps::CompareAndSwap(&lock_acquired_, 1, 0);
RTC_DCHECK_EQ(1, old_value) << "Unlock called without calling Lock first";
}
GlobalLockScope::GlobalLockScope(GlobalLock* lock) : lock_(lock) {
lock_->Lock();
}
GlobalLockScope::~GlobalLockScope() {
lock_->Unlock();
}
} // namespace rtc

23
rtc_base/critical_section.h
View File

@ -95,29 +95,6 @@ class RTC_SCOPED_LOCKABLE CritScope {
RTC_DISALLOW_COPY_AND_ASSIGN(CritScope);
};
// A lock used to protect global variables. Do NOT use for other purposes.
class RTC_LOCKABLE GlobalLock {
public:
constexpr GlobalLock() : lock_acquired_(0) {}
void Lock() RTC_EXCLUSIVE_LOCK_FUNCTION();
void Unlock() RTC_UNLOCK_FUNCTION();
private:
volatile int lock_acquired_;
};
// GlobalLockScope, for serializing execution through a scope.
class RTC_SCOPED_LOCKABLE GlobalLockScope {
public:
explicit GlobalLockScope(GlobalLock* lock) RTC_EXCLUSIVE_LOCK_FUNCTION(lock);
~GlobalLockScope() RTC_UNLOCK_FUNCTION();
private:
GlobalLock* const lock_;
RTC_DISALLOW_COPY_AND_ASSIGN(GlobalLockScope);
};
} // namespace rtc
#endif // RTC_BASE_CRITICAL_SECTION_H_

19
rtc_base/critical_section_unittest.cc
View File

@ -282,25 +282,6 @@ TEST(AtomicOpsTest, CompareAndSwap) {
EXPECT_EQ(1, runner.shared_value());
}
TEST(GlobalLockTest, CanHaveStaticStorageDuration) {
static_assert(std::is_trivially_destructible<GlobalLock>::value, "");
ABSL_CONST_INIT static GlobalLock global_lock;
global_lock.Lock();
global_lock.Unlock();
}
TEST(GlobalLockTest, Basic) {
// Create and start lots of threads.
LockRunner<GlobalLock> runner;
std::vector<std::unique_ptr<Thread>> threads;
StartThreads(&threads, &runner);
runner.SetExpectedThreadCount(kNumThreads);
// Release the hounds!
EXPECT_TRUE(runner.Run());
EXPECT_EQ(0, runner.shared_value());
}
TEST(CriticalSectionTest, Basic) {
// Create and start lots of threads.
LockRunner<CriticalSectionLock> runner;