emulator/opengl: refactor Thread class.

+ Add unit test.

Change-Id: I26d84cf590f6bfff3304be3f42dc0196bcc7f6d2

5 files changed, 453 insertions, 1 deletions

diff --git a/emulator/opengl/shared/emugl/common/Android.mk b/emulator/opengl/shared/emugl/common/Android.mk
index e75f887..fb9ab57 100644
--- a/emulator/opengl/shared/emugl/common/Android.mk
+++ b/emulator/opengl/shared/emugl/common/Android.mk
@@ -17,8 +17,12 @@ commonSources := \
 host_commonSources := $(commonSources)
 
 host_commonLdLibs := -lstdc++
+
 ifneq (windows,$(HOST_OS))
-    host_commonLdLibs += -ldl
+    host_commonSources += thread_pthread.cpp
+    host_commonLdLibs += -ldl -lpthread
+else
+    host_commonSources += thread_win32.cpp
 endif
 
 $(call emugl-begin-host-static-library,libemugl_common)
@@ -47,6 +51,7 @@ host_commonSources := \
     shared_library_unittest.cpp \
     smart_ptr_unittest.cpp \
     thread_store_unittest.cpp \
+    thread_unittest.cpp \
 
 $(call emugl-begin-host-executable,emugl_common_host_unittests)
 LOCAL_SRC_FILES := $(host_commonSources)
diff --git a/emulator/opengl/shared/emugl/common/thread.h b/emulator/opengl/shared/emugl/common/thread.h
new file mode 100644
index 0000000..d0f7d20
--- /dev/null
+++ b/emulator/opengl/shared/emugl/common/thread.h
@@ -0,0 +1,102 @@
+// Copyright (C) 2014 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef EMUGL_COMMON_THREAD_H
+#define EMUGL_COMMON_THREAD_H
+
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <pthread.h>
+#endif
+
+#include <stdint.h>
+
+namespace emugl {
+
+// Wrapper class for platform-specific threads.
+// To create your own thread, define a sub-class of emugl::Thread
+// and override its main() method.
+//
+// For example:
+//
+//    class MyThread : public emugl::Thread {
+//    public:
+//        MyThread() : Thread() {}
+//
+//        virtual intptr_t main() {
+//            ... main thread loop implementation
+//            return 0;
+//        }
+//    };
+//
+//    ...
+//
+//    // Create new instance, but does not start it.
+//    MyThread* thread = new MyThread();
+//
+//    // Start the thread.
+//    thread->start();
+//
+//    // Wait for thread completion, and gets result into |exitStatus|.
+//    int exitStatus;
+//    thread->wait(&exitStatus);
+//
+class Thread {
+public:
+    // Public constructor.
+    Thread();
+
+    // Virtual destructor.
+    virtual ~Thread();
+
+    // Override this method in your own thread sub-classes. This will
+    // be called when start() is invoked on the Thread instance.
+    virtual intptr_t main() = 0;
+
+    // Start a thread instance. Return true on success, false otherwise
+    // (e.g. if the thread was already started or terminated).
+    bool start();
+
+    // Wait for thread termination and retrieve exist status into
+    // |*exitStatus|. Return true on success, false otherwise.
+    // NOTE: |exitStatus| can be NULL.
+    bool  wait(intptr_t *exitStatus);
+
+    // Check whether a thread has terminated. On success, return true
+    // and sets |*exitStatus|. On failure, return false.
+    // NOTE: |exitStatus| can be NULL.
+    bool tryWait(intptr_t *exitStatus);
+
+private:
+#ifdef _WIN32
+    static DWORD WINAPI thread_main(void* arg);
+
+    HANDLE mThread;
+    DWORD mThreadId;
+    CRITICAL_SECTION mLock;
+#else // !WIN32
+    static void* thread_main(void* arg);
+
+    pthread_t mThread;
+    pthread_mutex_t mLock;
+#endif
+    intptr_t mExitStatus;
+    bool mIsRunning;
+};
+
+}  // namespace emugl
+
+#endif  // EMUGL_COMMON_THREAD_H
+
diff --git a/emulator/opengl/shared/emugl/common/thread_pthread.cpp b/emulator/opengl/shared/emugl/common/thread_pthread.cpp
new file mode 100644
index 0000000..5dbc3ab
--- /dev/null
+++ b/emulator/opengl/shared/emugl/common/thread_pthread.cpp
@@ -0,0 +1,114 @@
+// Copyright (C) 2014 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "emugl/common/thread.h"
+
+#include "emugl/common/thread_store.h"
+
+#include <stdio.h>
+
+namespace emugl {
+
+namespace {
+
+class ScopedLocker {
+public:
+    ScopedLocker(pthread_mutex_t* mutex) : mMutex(mutex) {
+        pthread_mutex_lock(mMutex);
+    }
+
+    ~ScopedLocker() {
+        pthread_mutex_unlock(mMutex);
+    }
+private:
+    pthread_mutex_t* mMutex;
+};
+
+}  // namespace
+
+Thread::Thread() :
+    mThread((pthread_t)NULL),
+    mExitStatus(0),
+    mIsRunning(false) {
+    pthread_mutex_init(&mLock, NULL);
+}
+
+Thread::~Thread() {
+    pthread_mutex_destroy(&mLock);
+}
+
+bool Thread::start() {
+    bool ret = true;
+    pthread_mutex_lock(&mLock);
+    mIsRunning = true;
+    if (pthread_create(&mThread, NULL, thread_main, this)) {
+        ret = false;
+        mIsRunning = false;
+    }
+    pthread_mutex_unlock(&mLock);
+    return ret;
+}
+
+bool Thread::wait(intptr_t *exitStatus) {
+    {
+        ScopedLocker locker(&mLock);
+        if (!mIsRunning) {
+            // Thread already stopped.
+            if (exitStatus) {
+                *exitStatus = mExitStatus;
+            }
+            return true;
+        }
+    }
+
+    // NOTE: Do not hold the lock when waiting for the thread to ensure
+    // it can update mIsRunning and mExitStatus properly in thread_main
+    // without blocking.
+    void *retval;
+    if (pthread_join(mThread, &retval)) {
+        return false;
+    }
+    if (exitStatus) {
+        *exitStatus = (intptr_t)retval;
+    }
+    return true;
+}
+
+bool Thread::tryWait(intptr_t *exitStatus) {
+    ScopedLocker locker(&mLock);
+    if (!mIsRunning) {
+        return false;
+    }
+    if (exitStatus) {
+        *exitStatus = mExitStatus;
+    }
+    return true;
+}
+
+// static
+void* Thread::thread_main(void *arg) {
+    Thread* self = reinterpret_cast<Thread*>(arg);
+    intptr_t ret = self->main();
+
+    pthread_mutex_lock(&self->mLock);
+    self->mIsRunning = false;
+    self->mExitStatus = ret;
+    pthread_mutex_unlock(&self->mLock);
+
+    ::emugl::ThreadStore::OnThreadExit();
+
+    return (void*)ret;
+}
+
+}  // namespace emugl
diff --git a/emulator/opengl/shared/emugl/common/thread_unittest.cpp b/emulator/opengl/shared/emugl/common/thread_unittest.cpp
new file mode 100644
index 0000000..db1931f
--- /dev/null
+++ b/emulator/opengl/shared/emugl/common/thread_unittest.cpp
@@ -0,0 +1,109 @@
+// Copyright (C) 2014 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "emugl/common/thread.h"
+
+#include "emugl/common/mutex.h"
+
+#include <gtest/gtest.h>
+
+namespace emugl {
+
+namespace {
+
+// A simple thread instance that does nothing at all and exits immediately.
+class EmptyThread : public ::emugl::Thread {
+public:
+    intptr_t main() { return 42; }
+};
+
+class CountingThread : public ::emugl::Thread {
+public:
+    class State {
+    public:
+        State() : mLock(), mCount(0) {}
+        ~State() {}
+
+        void increment() {
+            mLock.lock();
+            mCount++;
+            mLock.unlock();
+        }
+
+        int count() const {
+            int ret;
+            mLock.lock();
+            ret = mCount;
+            mLock.unlock();
+            return ret;
+        }
+
+    private:
+        mutable Mutex mLock;
+        int mCount;
+    };
+
+    CountingThread(State* state) : mState(state) {}
+
+    intptr_t main() {
+        mState->increment();
+        return 0;
+    }
+
+private:
+    State* mState;
+};
+
+}  // namespace
+
+TEST(ThreadTest, SimpleThread) {
+    Thread* thread = new EmptyThread();
+    EXPECT_TRUE(thread);
+    EXPECT_TRUE(thread->start());
+    intptr_t status;
+    EXPECT_TRUE(thread->wait(&status));
+    EXPECT_EQ(42, status);
+}
+
+TEST(ThreadTest, MultipleThreads) {
+    CountingThread::State state;
+    const size_t kMaxThreads = 100;
+    Thread* threads[kMaxThreads];
+
+    // Create all threads.
+    for (size_t n = 0; n < kMaxThreads; ++n) {
+        threads[n] = new CountingThread(&state);
+        EXPECT_TRUE(threads[n]) << "thread " << n;
+    }
+
+    // Start them all.
+    for (size_t n = 0; n < kMaxThreads; ++n) {
+        EXPECT_TRUE(threads[n]->start()) << "thread " << n;
+    }
+
+    // Wait for them all.
+    for (size_t n = 0; n < kMaxThreads; ++n) {
+        EXPECT_TRUE(threads[n]->wait(NULL)) << "thread " << n;
+    }
+
+    // Check state.
+    EXPECT_EQ((int)kMaxThreads, state.count());
+
+    // Delete them all.
+    for (size_t n = 0; n < kMaxThreads; ++n) {
+        delete threads[n];
+    }
+}
+
+}  // namespace emugl
diff --git a/emulator/opengl/shared/emugl/common/thread_win32.cpp b/emulator/opengl/shared/emugl/common/thread_win32.cpp
new file mode 100644
index 0000000..f348ca8
--- /dev/null
+++ b/emulator/opengl/shared/emugl/common/thread_win32.cpp
@@ -0,0 +1,122 @@
+// Copyright (C) 2014 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "emugl/common/thread.h"
+
+#include "emugl/common/thread_store.h"
+
+namespace emugl {
+
+namespace {
+
+class ScopedLocker {
+public:
+    ScopedLocker(CRITICAL_SECTION* section) : mSection(section) {
+        EnterCriticalSection(mSection);
+    }
+
+    ~ScopedLocker() {
+        LeaveCriticalSection(mSection);
+    }
+private:
+    CRITICAL_SECTION* mSection;
+};
+
+}  // namespace
+
+Thread::Thread() :
+    mThread(INVALID_HANDLE_VALUE),
+    mThreadId(0),
+    mExitStatus(0),
+    mIsRunning(false) {
+    InitializeCriticalSection(&mLock);
+}
+
+Thread::~Thread() {
+    if(mThread != INVALID_HANDLE_VALUE) {
+        CloseHandle(mThread);
+    }
+    DeleteCriticalSection(&mLock);
+}
+
+bool Thread::start() {
+    ScopedLocker locker(&mLock);
+
+    bool ret = true;
+    mIsRunning = true;
+    mThread = CreateThread(NULL, 0, &Thread::thread_main, this, 0, &mThreadId);
+    if (!mThread) {
+        ret = false;
+        mIsRunning = false;
+    }
+    return ret;
+}
+
+bool Thread::wait(intptr_t* exitStatus) {
+    {
+        ScopedLocker locker(&mLock);
+        if (!mIsRunning) {
+            // Thread already stopped.
+            if (exitStatus) {
+                *exitStatus = mExitStatus;
+            }
+            return true;
+        }
+    }
+
+    // NOTE: Do not hold lock during wait to aloow thread_main to
+    // properly update mIsRunning and mExitStatus on thread exit.
+    if (WaitForSingleObject(mThread, INFINITE) == WAIT_FAILED) {
+        return false;
+    }
+
+    if (exitStatus) {
+        ScopedLocker locker(&mLock);
+        *exitStatus = mExitStatus;
+    }
+    return true;
+}
+
+bool Thread::tryWait(intptr_t* exitStatus) {
+    ScopedLocker locker(&mLock);
+
+    if (!mIsRunning ||
+        WaitForSingleObject(mThread, 0) != WAIT_OBJECT_0) {
+        return false;
+    }
+
+    if (exitStatus) {
+        *exitStatus = mExitStatus;
+    }
+    return true;
+}
+
+// static
+DWORD WINAPI Thread::thread_main(void *arg)
+{
+    Thread* self = reinterpret_cast<Thread*>(arg);
+    intptr_t ret = self->main();
+
+    EnterCriticalSection(&self->mLock);
+    self->mIsRunning = false;
+    self->mExitStatus = ret;
+    LeaveCriticalSection(&self->mLock);
+
+    // Ensure all thread-local values are released for this thread.
+    ::emugl::ThreadStore::OnThreadExit();
+
+    return static_cast<DWORD>(ret);
+}
+
+}  // namespace emugl