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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "nsThreadUtils.h"
#include "mozilla/Atomics.h"
#include "mozilla/gtest/MozAssertions.h"
#include "mozilla/RWLock.h"
#include "mozilla/SyncRunnable.h"
#include "nsIThread.h"
#include "gtest/gtest.h"
using mozilla::AutoReadLock;
using mozilla::AutoTryReadLock;
using mozilla::AutoTryWriteLock;
using mozilla::AutoWriteLock;
using mozilla::RWLock;
static const size_t sNumThreads = 4;
static const size_t sOuterIterations = 100;
static const size_t sInnerIterations = 100;
static const size_t sWriteLockIteration = 10;
// Based on example code from _Programming with POSIX Threads_. Not an actual
// test of correctness, but more of a "does this work at all" sort of test.
class RWLockRunnable : public mozilla::Runnable {
public:
RWLockRunnable(RWLock* aRWLock, mozilla::Atomic<size_t>* aSharedData)
: mozilla::Runnable("RWLockRunnable"),
mRWLock(aRWLock),
mSharedData(aSharedData) {}
NS_DECL_NSIRUNNABLE
private:
~RWLockRunnable() = default;
RWLock* mRWLock;
mozilla::Atomic<size_t>* mSharedData;
};
NS_IMETHODIMP
RWLockRunnable::Run() {
for (size_t i = 0; i < sOuterIterations; ++i) {
if (i % sWriteLockIteration == 0) {
mozilla::AutoWriteLock lock(*mRWLock);
++(*mSharedData);
} else {
mozilla::AutoReadLock lock(*mRWLock);
// Loop and try to force other threads to run, but check that our
// shared data isn't being modified by them.
size_t initialValue = *mSharedData;
for (size_t j = 0; j < sInnerIterations; ++j) {
EXPECT_EQ(initialValue, *mSharedData);
// This is a magic yield call.
PR_Sleep(PR_INTERVAL_NO_WAIT);
}
}
}
return NS_OK;
}
TEST(RWLock, SmokeTest)
{
nsCOMPtr<nsIThread> threads[sNumThreads];
RWLock rwlock MOZ_UNANNOTATED("test lock");
mozilla::Atomic<size_t> data(0);
for (size_t i = 0; i < sNumThreads; ++i) {
nsCOMPtr<nsIRunnable> event = new RWLockRunnable(&rwlock, &data);
NS_NewNamedThread("RWLockTester", getter_AddRefs(threads[i]), event);
}
// Wait for all the threads to finish.
for (size_t i = 0; i < sNumThreads; ++i) {
nsresult rv = threads[i]->Shutdown();
EXPECT_NS_SUCCEEDED(rv);
}
EXPECT_EQ(data, (sOuterIterations / sWriteLockIteration) * sNumThreads);
}
template <typename Function>
static std::invoke_result_t<Function> RunOnBackgroundThread(
Function&& aFunction) {
using Result = std::invoke_result_t<Function>;
nsCOMPtr<nsISerialEventTarget> thread;
MOZ_ALWAYS_SUCCEEDS(NS_CreateBackgroundTaskQueue(
"TestRWLock Background Thread", getter_AddRefs(thread)));
mozilla::Maybe<Result> tryResult;
RefPtr<nsIRunnable> runnable =
NS_NewRunnableFunction(__func__, [&] { tryResult.emplace(aFunction()); });
MOZ_ALWAYS_SUCCEEDS(
mozilla::SyncRunnable::DispatchToThread(thread.get(), runnable));
return *tryResult;
}
TEST(RWLock, AutoTryReadLock)
{
RWLock l1 MOZ_UNANNOTATED("autotryreadlock");
{
AutoTryReadLock autol1(l1);
EXPECT_TRUE(autol1);
AutoTryReadLock autol2(l1);
EXPECT_TRUE(autol2);
EXPECT_TRUE(RunOnBackgroundThread([&] {
AutoTryReadLock lock(l1);
return !!lock;
}));
EXPECT_TRUE(autol1);
EXPECT_TRUE(autol2);
{
RWLock l2 MOZ_UNANNOTATED("autotryreadlock2");
AutoTryReadLock autol3(l2);
EXPECT_TRUE(autol3);
}
EXPECT_TRUE(autol1);
EXPECT_TRUE(autol2);
}
{
AutoWriteLock autol4(l1);
MOZ_ASSERT(l1.LockedForWritingByCurrentThread());
AutoTryReadLock autol5(l1);
EXPECT_FALSE(autol5);
EXPECT_FALSE(RunOnBackgroundThread([&] {
AutoTryReadLock lock(l1);
return !!lock;
}));
}
AutoTryReadLock autol6(l1);
EXPECT_TRUE(autol6);
EXPECT_TRUE(RunOnBackgroundThread([&] {
AutoTryReadLock lock(l1);
return !!lock;
}));
}
TEST(RWLock, AutoTryWriteLock)
{
RWLock l1 MOZ_UNANNOTATED("autotrywritelock");
{
AutoTryWriteLock autol1(l1);
EXPECT_TRUE(autol1);
AutoTryReadLock autol2(l1);
EXPECT_FALSE(autol2);
EXPECT_FALSE(RunOnBackgroundThread([&] {
AutoTryWriteLock lock(l1);
return !!lock;
}));
EXPECT_TRUE(autol1);
EXPECT_FALSE(autol2);
{
RWLock l2 MOZ_UNANNOTATED("autotrywritelock2");
AutoTryWriteLock autol3(l2);
EXPECT_TRUE(autol3);
}
EXPECT_TRUE(autol1);
EXPECT_FALSE(autol2);
}
{
AutoReadLock autol4(l1);
AutoTryWriteLock autol5(l1);
EXPECT_FALSE(autol5);
EXPECT_FALSE(RunOnBackgroundThread([&] {
AutoTryWriteLock lock(l1);
return !!lock;
}));
}
{
AutoWriteLock autol6(l1);
MOZ_ASSERT(l1.LockedForWritingByCurrentThread());
AutoTryWriteLock autol7(l1);
EXPECT_FALSE(autol7);
EXPECT_FALSE(RunOnBackgroundThread([&] {
AutoTryWriteLock lock(l1);
return !!lock;
}));
}
AutoTryWriteLock autol8(l1);
EXPECT_TRUE(autol8);
}
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