auto import from //depot/cupcake/@135843

1 files changed, 1128 insertions, 0 deletions

diff --git a/libs/utils/Threads.cpp b/libs/utils/Threads.cpp
new file mode 100644
index 0000000..5f407a9
--- /dev/null
+++ b/libs/utils/Threads.cpp
@@ -0,0 +1,1128 @@
+/*
+ * Copyright (C) 2007 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.
+ */
+
+#define LOG_TAG "libutils.threads"
+
+#include <utils/threads.h>
+#include <utils/Log.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <memory.h>
+#include <errno.h>
+#include <assert.h>
+#include <unistd.h>
+
+#if defined(HAVE_PTHREADS)
+# include <pthread.h>
+# include <sched.h>
+# include <sys/resource.h>
+#elif defined(HAVE_WIN32_THREADS)
+# include <windows.h>
+# include <stdint.h>
+# include <process.h>
+# define HAVE_CREATETHREAD  // Cygwin, vs. HAVE__BEGINTHREADEX for MinGW
+#endif
+
+#if defined(HAVE_FUTEX)
+#include <private/utils/futex_synchro.h>
+#endif
+
+#if defined(HAVE_PRCTL)
+#include <sys/prctl.h>
+#endif
+
+/*
+ * ===========================================================================
+ *      Thread wrappers
+ * ===========================================================================
+ */
+
+using namespace android;
+
+// ----------------------------------------------------------------------------
+#if defined(HAVE_PTHREADS)
+#if 0
+#pragma mark -
+#pragma mark PTHREAD
+#endif
+// ----------------------------------------------------------------------------
+
+/*
+ * Create and run a new thead.
+ *
+ * We create it "detached", so it cleans up after itself.
+ */
+
+typedef void* (*android_pthread_entry)(void*);
+
+struct thread_data_t {
+    thread_func_t   entryFunction;
+    void*           userData;
+    int             priority;
+    char *          threadName;
+
+    // we use this trampoline when we need to set the priority with
+    // nice/setpriority.
+    static int trampoline(const thread_data_t* t) {
+        thread_func_t f = t->entryFunction;
+        void* u = t->userData;
+        int prio = t->priority;
+        char * name = t->threadName;
+        delete t;
+        setpriority(PRIO_PROCESS, 0, prio);
+        if (name) {
+#if defined(HAVE_PRCTL)
+            // Mac OS doesn't have this, and we build libutil for the host too
+            int hasAt = 0;
+            int hasDot = 0;
+            char *s = name;
+            while (*s) {
+                if (*s == '.') hasDot = 1;
+                else if (*s == '@') hasAt = 1;
+                s++;
+            }
+            int len = s - name;
+            if (len < 15 || hasAt || !hasDot) {
+                s = name;
+            } else {
+                s = name + len - 15;
+            }
+            prctl(PR_SET_NAME, (unsigned long) s, 0, 0, 0);
+#endif
+            free(name);
+        }
+        return f(u);
+    }
+};
+
+int androidCreateRawThreadEtc(android_thread_func_t entryFunction,
+                               void *userData,
+                               const char* threadName,
+                               int32_t threadPriority,
+                               size_t threadStackSize,
+                               android_thread_id_t *threadId)
+{
+    pthread_attr_t attr; 
+    pthread_attr_init(&attr);
+    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+
+#ifdef HAVE_ANDROID_OS  /* valgrind is rejecting RT-priority create reqs */
+    if (threadPriority != PRIORITY_DEFAULT || threadName != NULL) {
+        // We could avoid the trampoline if there was a way to get to the
+        // android_thread_id_t (pid) from pthread_t
+        thread_data_t* t = new thread_data_t;
+        t->priority = threadPriority;
+        t->threadName = threadName ? strdup(threadName) : NULL;
+        t->entryFunction = entryFunction;
+        t->userData = userData;
+        entryFunction = (android_thread_func_t)&thread_data_t::trampoline;
+        userData = t;            
+    }
+#endif
+
+    if (threadStackSize) {
+        pthread_attr_setstacksize(&attr, threadStackSize);
+    }
+    
+    errno = 0;
+    pthread_t thread;
+    int result = pthread_create(&thread, &attr,
+                    (android_pthread_entry)entryFunction, userData);
+    if (result != 0) {
+        LOGE("androidCreateRawThreadEtc failed (entry=%p, res=%d, errno=%d)\n"
+             "(android threadPriority=%d)",
+            entryFunction, result, errno, threadPriority);
+        return 0;
+    }
+
+    if (threadId != NULL) {
+        *threadId = (android_thread_id_t)thread; // XXX: this is not portable
+    }
+    return 1;
+}
+
+android_thread_id_t androidGetThreadId()
+{
+    return (android_thread_id_t)pthread_self();
+}
+
+// ----------------------------------------------------------------------------
+#elif defined(HAVE_WIN32_THREADS)
+#if 0
+#pragma mark -
+#pragma mark WIN32_THREADS
+#endif
+// ----------------------------------------------------------------------------
+
+/*
+ * Trampoline to make us __stdcall-compliant.
+ *
+ * We're expected to delete "vDetails" when we're done.
+ */
+struct threadDetails {
+    int (*func)(void*);
+    void* arg;
+};
+static __stdcall unsigned int threadIntermediary(void* vDetails)
+{
+    struct threadDetails* pDetails = (struct threadDetails*) vDetails;
+    int result;
+
+    result = (*(pDetails->func))(pDetails->arg);
+
+    delete pDetails;
+
+    LOG(LOG_VERBOSE, "thread", "thread exiting\n");
+    return (unsigned int) result;
+}
+
+/*
+ * Create and run a new thread.
+ */
+static bool doCreateThread(android_thread_func_t fn, void* arg, android_thread_id_t *id)
+{
+    HANDLE hThread;
+    struct threadDetails* pDetails = new threadDetails; // must be on heap
+    unsigned int thrdaddr;
+
+    pDetails->func = fn;
+    pDetails->arg = arg;
+
+#if defined(HAVE__BEGINTHREADEX)
+    hThread = (HANDLE) _beginthreadex(NULL, 0, threadIntermediary, pDetails, 0,
+                    &thrdaddr);
+    if (hThread == 0)
+#elif defined(HAVE_CREATETHREAD)
+    hThread = CreateThread(NULL, 0,
+                    (LPTHREAD_START_ROUTINE) threadIntermediary,
+                    (void*) pDetails, 0, (DWORD*) &thrdaddr);
+    if (hThread == NULL)
+#endif
+    {
+        LOG(LOG_WARN, "thread", "WARNING: thread create failed\n");
+        return false;
+    }
+
+#if defined(HAVE_CREATETHREAD)
+    /* close the management handle */
+    CloseHandle(hThread);
+#endif
+
+    if (id != NULL) {
+      	*id = (android_thread_id_t)thrdaddr;
+    }
+
+    return true;
+}
+
+int androidCreateRawThreadEtc(android_thread_func_t fn,
+                               void *userData,
+                               const char* threadName,
+                               int32_t threadPriority,
+                               size_t threadStackSize,
+                               android_thread_id_t *threadId)
+{
+    return doCreateThread(  fn, userData, threadId);
+}
+
+android_thread_id_t androidGetThreadId()
+{
+    return (android_thread_id_t)GetCurrentThreadId();
+}
+
+// ----------------------------------------------------------------------------
+#else
+#error "Threads not supported"
+#endif
+
+// ----------------------------------------------------------------------------
+
+#if 0
+#pragma mark -
+#pragma mark Common Thread functions
+#endif
+
+int androidCreateThread(android_thread_func_t fn, void* arg)
+{
+    return createThreadEtc(fn, arg);
+}
+
+int androidCreateThreadGetID(android_thread_func_t fn, void *arg, android_thread_id_t *id)
+{
+    return createThreadEtc(fn, arg, "android:unnamed_thread",
+                           PRIORITY_DEFAULT, 0, id);
+}
+
+static android_create_thread_fn gCreateThreadFn = androidCreateRawThreadEtc;
+
+int androidCreateThreadEtc(android_thread_func_t entryFunction,
+                            void *userData,
+                            const char* threadName,
+                            int32_t threadPriority,
+                            size_t threadStackSize,
+                            android_thread_id_t *threadId)
+{
+    return gCreateThreadFn(entryFunction, userData, threadName,
+        threadPriority, threadStackSize, threadId);
+}
+
+void androidSetCreateThreadFunc(android_create_thread_fn func)
+{
+    gCreateThreadFn = func;
+}
+
+namespace android {
+
+/*
+ * ===========================================================================
+ *      Mutex class
+ * ===========================================================================
+ */
+
+#if 0
+#pragma mark -
+#pragma mark Mutex
+#endif
+
+#if defined(HAVE_PTHREADS) && !defined(HAVE_FUTEX)
+/*
+ * Simple pthread wrapper.
+ */
+
+Mutex::Mutex()
+{
+    _init();
+}
+
+Mutex::Mutex(const char* name)
+{
+    // XXX: name not used for now
+    _init();
+}
+
+void Mutex::_init()
+{
+    pthread_mutex_t* pMutex = new pthread_mutex_t;
+    pthread_mutex_init(pMutex, NULL);
+    mState = pMutex;
+}
+
+Mutex::~Mutex()
+{
+    delete (pthread_mutex_t*) mState;
+}
+
+status_t Mutex::lock()
+{
+    int res;
+    while ((res=pthread_mutex_lock((pthread_mutex_t*) mState)) == EINTR) ;
+    return -res;
+}
+
+void Mutex::unlock()
+{
+    pthread_mutex_unlock((pthread_mutex_t*) mState);
+}
+
+status_t Mutex::tryLock()
+{
+    int res;
+    while ((res=pthread_mutex_trylock((pthread_mutex_t*) mState)) == EINTR) ;
+    return -res;
+}
+
+#elif defined(HAVE_FUTEX)
+#if 0
+#pragma mark -
+#endif
+
+#define STATE ((futex_mutex_t*) (&mState))
+
+Mutex::Mutex()
+{
+    _init();
+}
+
+Mutex::Mutex(const char* name)
+{
+    _init();
+}
+
+void
+Mutex::_init()
+{
+    futex_mutex_init(STATE);
+}
+
+Mutex::~Mutex()
+{
+}
+
+status_t Mutex::lock()
+{
+    int res;
+    while ((res=futex_mutex_lock(STATE, FUTEX_WAIT_INFINITE)) == EINTR) ;
+    return -res;
+}
+
+void Mutex::unlock()
+{
+    futex_mutex_unlock(STATE);
+}
+
+status_t Mutex::tryLock()
+{
+    int res;
+    while ((res=futex_mutex_trylock(STATE)) == EINTR) ;
+    return -res;
+}
+#undef STATE
+
+#elif defined(HAVE_WIN32_THREADS)
+#if 0
+#pragma mark -
+#endif
+
+Mutex::Mutex()
+{
+    HANDLE hMutex;
+
+    assert(sizeof(hMutex) == sizeof(mState));
+
+    hMutex = CreateMutex(NULL, FALSE, NULL);
+    mState = (void*) hMutex;
+}
+
+Mutex::Mutex(const char* name)
+{
+    // XXX: name not used for now
+    HANDLE hMutex;
+
+    hMutex = CreateMutex(NULL, FALSE, NULL);
+    mState = (void*) hMutex;
+}
+
+Mutex::~Mutex()
+{
+    CloseHandle((HANDLE) mState);
+}
+
+status_t Mutex::lock()
+{
+    DWORD dwWaitResult;
+    dwWaitResult = WaitForSingleObject((HANDLE) mState, INFINITE);
+    return dwWaitResult != WAIT_OBJECT_0 ? -1 : NO_ERROR;
+}
+
+void Mutex::unlock()
+{
+    if (!ReleaseMutex((HANDLE) mState))
+        LOG(LOG_WARN, "thread", "WARNING: bad result from unlocking mutex\n");
+}
+
+status_t Mutex::tryLock()
+{
+    DWORD dwWaitResult;
+
+    dwWaitResult = WaitForSingleObject((HANDLE) mState, 0);
+    if (dwWaitResult != WAIT_OBJECT_0 && dwWaitResult != WAIT_TIMEOUT)
+        LOG(LOG_WARN, "thread", "WARNING: bad result from try-locking mutex\n");
+    return (dwWaitResult == WAIT_OBJECT_0) ? 0 : -1;
+}
+
+#else
+#error "Somebody forgot to implement threads for this platform."
+#endif
+
+
+/*
+ * ===========================================================================
+ *      Condition class
+ * ===========================================================================
+ */
+
+#if 0
+#pragma mark -
+#pragma mark Condition
+#endif
+
+#if defined(HAVE_PTHREADS) && !defined(HAVE_FUTEX)
+
+/*
+ * Constructor.  This is a simple pthread wrapper.
+ */
+Condition::Condition()
+{
+    pthread_cond_t* pCond = new pthread_cond_t;
+
+    pthread_cond_init(pCond, NULL);
+    mState = pCond;
+}
+
+/*
+ * Destructor.
+ */
+Condition::~Condition()
+{
+    pthread_cond_destroy((pthread_cond_t*) mState);
+    delete (pthread_cond_t*) mState;
+}
+
+/*
+ * Wait on a condition variable.  Lock the mutex before calling.
+ */
+
+status_t Condition::wait(Mutex& mutex)
+{
+    assert(mutex.mState != NULL);
+
+    int cc;
+    while ((cc = pthread_cond_wait((pthread_cond_t*)mState,
+                (pthread_mutex_t*) mutex.mState)) == EINTR) ;
+    return -cc;
+}
+
+status_t Condition::wait(Mutex& mutex, nsecs_t abstime)
+{
+    assert(mutex.mState != NULL);
+
+    struct timespec ts;
+    ts.tv_sec = abstime/1000000000;
+    ts.tv_nsec = abstime-(ts.tv_sec*1000000000);
+    
+    int cc;
+    while ((cc = pthread_cond_timedwait((pthread_cond_t*)mState,
+            (pthread_mutex_t*) mutex.mState, &ts)) == EINTR) ;
+    return -cc;
+}
+
+status_t Condition::waitRelative(Mutex& mutex, nsecs_t reltime)
+{
+    return wait(mutex, systemTime()+reltime);
+}
+
+/*
+ * Signal the condition variable, allowing one thread to continue.
+ */
+void Condition::signal()
+{
+    pthread_cond_signal((pthread_cond_t*) mState);
+}
+
+/*
+ * Signal the condition variable, allowing all threads to continue.
+ */
+void Condition::broadcast()
+{
+    pthread_cond_broadcast((pthread_cond_t*) mState);
+}
+
+#elif defined(HAVE_FUTEX)
+#if 0
+#pragma mark -
+#endif
+
+#define STATE ((futex_cond_t*) (&mState))
+
+/*
+ * Constructor.  This is a simple pthread wrapper.
+ */
+Condition::Condition()
+{
+    futex_cond_init(STATE);
+}
+
+/*
+ * Destructor.
+ */
+Condition::~Condition()
+{
+}
+
+/*
+ * Wait on a condition variable.  Lock the mutex before calling.
+ */
+
+status_t Condition::wait(Mutex& mutex)
+{
+    assert(mutex.mState != NULL);
+
+    int res;
+    while ((res = futex_cond_wait(STATE,
+        (futex_mutex_t*)(&mutex.mState), FUTEX_WAIT_INFINITE)) == -EINTR) ;
+
+    return -res;
+}
+
+status_t Condition::wait(Mutex& mutex, nsecs_t abstime)
+{
+    nsecs_t reltime = abstime - systemTime();
+    if (reltime <= 0) return true;
+    return waitRelative(mutex, reltime);
+}
+
+status_t Condition::waitRelative(Mutex& mutex, nsecs_t reltime)
+{
+    assert(mutex.mState != NULL);
+    int res;
+    unsigned msec = ns2ms(reltime);
+    if(msec == 0)
+        return true;
+    // This code will not time out at the correct time if interrupted by signals
+    while ((res = futex_cond_wait(STATE,
+        (futex_mutex_t*)(&mutex.mState), msec)) == -EINTR) ;
+    return res;
+}
+
+/*
+ * Signal the condition variable, allowing one thread to continue.
+ */
+void Condition::signal()
+{
+    futex_cond_signal(STATE);
+}
+
+/*
+ * Signal the condition variable, allowing all threads to continue.
+ */
+void Condition::broadcast()
+{
+    futex_cond_broadcast(STATE);
+}
+
+#undef STATE
+
+#elif defined(HAVE_WIN32_THREADS)
+#if 0
+#pragma mark -
+#endif
+
+/*
+ * Windows doesn't have a condition variable solution.  It's possible
+ * to create one, but it's easy to get it wrong.  For a discussion, and
+ * the origin of this implementation, see:
+ *
+ *  http://www.cs.wustl.edu/~schmidt/win32-cv-1.html
+ *
+ * The implementation shown on the page does NOT follow POSIX semantics.
+ * As an optimization they require acquiring the external mutex before
+ * calling signal() and broadcast(), whereas POSIX only requires grabbing
+ * it before calling wait().  The implementation here has been un-optimized
+ * to have the correct behavior.
+ */
+typedef struct WinCondition {
+    // Number of waiting threads.
+    int                 waitersCount;
+
+    // Serialize access to waitersCount.
+    CRITICAL_SECTION    waitersCountLock;
+
+    // Semaphore used to queue up threads waiting for the condition to
+    // become signaled.
+    HANDLE              sema;
+
+    // An auto-reset event used by the broadcast/signal thread to wait
+    // for all the waiting thread(s) to wake up and be released from
+    // the semaphore.
+    HANDLE              waitersDone;
+
+    // This mutex wouldn't be necessary if we required that the caller
+    // lock the external mutex before calling signal() and broadcast().
+    // I'm trying to mimic pthread semantics though.
+    HANDLE              internalMutex;
+
+    // Keeps track of whether we were broadcasting or signaling.  This
+    // allows us to optimize the code if we're just signaling.
+    bool                wasBroadcast;
+
+    status_t wait(WinCondition* condState, HANDLE hMutex, nsecs_t* abstime)
+    {
+        // Increment the wait count, avoiding race conditions.
+        EnterCriticalSection(&condState->waitersCountLock);
+        condState->waitersCount++;
+        //printf("+++ wait: incr waitersCount to %d (tid=%ld)\n",
+        //    condState->waitersCount, getThreadId());
+        LeaveCriticalSection(&condState->waitersCountLock);
+    
+        DWORD timeout = INFINITE;
+        if (abstime) {
+            nsecs_t reltime = *abstime - systemTime();
+            if (reltime < 0)
+                reltime = 0;
+            timeout = reltime/1000000;
+        }
+        
+        // Atomically release the external mutex and wait on the semaphore.
+        DWORD res =
+            SignalObjectAndWait(hMutex, condState->sema, timeout, FALSE);
+    
+        //printf("+++ wait: awake (tid=%ld)\n", getThreadId());
+    
+        // Reacquire lock to avoid race conditions.
+        EnterCriticalSection(&condState->waitersCountLock);
+    
+        // No longer waiting.
+        condState->waitersCount--;
+    
+        // Check to see if we're the last waiter after a broadcast.
+        bool lastWaiter = (condState->wasBroadcast && condState->waitersCount == 0);
+    
+        //printf("+++ wait: lastWaiter=%d (wasBc=%d wc=%d)\n",
+        //    lastWaiter, condState->wasBroadcast, condState->waitersCount);
+    
+        LeaveCriticalSection(&condState->waitersCountLock);
+    
+        // If we're the last waiter thread during this particular broadcast
+        // then signal broadcast() that we're all awake.  It'll drop the
+        // internal mutex.
+        if (lastWaiter) {
+            // Atomically signal the "waitersDone" event and wait until we
+            // can acquire the internal mutex.  We want to do this in one step
+            // because it ensures that everybody is in the mutex FIFO before
+            // any thread has a chance to run.  Without it, another thread
+            // could wake up, do work, and hop back in ahead of us.
+            SignalObjectAndWait(condState->waitersDone, condState->internalMutex,
+                INFINITE, FALSE);
+        } else {
+            // Grab the internal mutex.
+            WaitForSingleObject(condState->internalMutex, INFINITE);
+        }
+    
+        // Release the internal and grab the external.
+        ReleaseMutex(condState->internalMutex);
+        WaitForSingleObject(hMutex, INFINITE);
+    
+        return res == WAIT_OBJECT_0 ? NO_ERROR : -1;
+    }
+} WinCondition;
+
+/*
+ * Constructor.  Set up the WinCondition stuff.
+ */
+Condition::Condition()
+{
+    WinCondition* condState = new WinCondition;
+
+    condState->waitersCount = 0;
+    condState->wasBroadcast = false;
+    // semaphore: no security, initial value of 0
+    condState->sema = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
+    InitializeCriticalSection(&condState->waitersCountLock);
+    // auto-reset event, not signaled initially
+    condState->waitersDone = CreateEvent(NULL, FALSE, FALSE, NULL);
+    // used so we don't have to lock external mutex on signal/broadcast
+    condState->internalMutex = CreateMutex(NULL, FALSE, NULL);
+
+    mState = condState;
+}
+
+/*
+ * Destructor.  Free Windows resources as well as our allocated storage.
+ */
+Condition::~Condition()
+{
+    WinCondition* condState = (WinCondition*) mState;
+    if (condState != NULL) {
+        CloseHandle(condState->sema);
+        CloseHandle(condState->waitersDone);
+        delete condState;
+    }
+}
+
+
+status_t Condition::wait(Mutex& mutex)
+{
+    WinCondition* condState = (WinCondition*) mState;
+    HANDLE hMutex = (HANDLE) mutex.mState;
+    
+    return ((WinCondition*)mState)->wait(condState, hMutex, NULL);
+}
+
+status_t Condition::wait(Mutex& mutex, nsecs_t abstime)
+{
+    WinCondition* condState = (WinCondition*) mState;
+    HANDLE hMutex = (HANDLE) mutex.mState;
+
+    return ((WinCondition*)mState)->wait(condState, hMutex, &abstime);
+}
+
+status_t Condition::waitRelative(Mutex& mutex, nsecs_t reltime)
+{
+    return wait(mutex, systemTime()+reltime);
+}
+
+/*
+ * Signal the condition variable, allowing one thread to continue.
+ */
+void Condition::signal()
+{
+    WinCondition* condState = (WinCondition*) mState;
+
+    // Lock the internal mutex.  This ensures that we don't clash with
+    // broadcast().
+    WaitForSingleObject(condState->internalMutex, INFINITE);
+
+    EnterCriticalSection(&condState->waitersCountLock);
+    bool haveWaiters = (condState->waitersCount > 0);
+    LeaveCriticalSection(&condState->waitersCountLock);
+
+    // If no waiters, then this is a no-op.  Otherwise, knock the semaphore
+    // down a notch.
+    if (haveWaiters)
+        ReleaseSemaphore(condState->sema, 1, 0);
+
+    // Release internal mutex.
+    ReleaseMutex(condState->internalMutex);
+}
+
+/*
+ * Signal the condition variable, allowing all threads to continue.
+ *
+ * First we have to wake up all threads waiting on the semaphore, then
+ * we wait until all of the threads have actually been woken before
+ * releasing the internal mutex.  This ensures that all threads are woken.
+ */
+void Condition::broadcast()
+{
+    WinCondition* condState = (WinCondition*) mState;
+
+    // Lock the internal mutex.  This keeps the guys we're waking up
+    // from getting too far.
+    WaitForSingleObject(condState->internalMutex, INFINITE);
+
+    EnterCriticalSection(&condState->waitersCountLock);
+    bool haveWaiters = false;
+
+    if (condState->waitersCount > 0) {
+        haveWaiters = true;
+        condState->wasBroadcast = true;
+    }
+
+    if (haveWaiters) {
+        // Wake up all the waiters.
+        ReleaseSemaphore(condState->sema, condState->waitersCount, 0);
+
+        LeaveCriticalSection(&condState->waitersCountLock);
+
+        // Wait for all awakened threads to acquire the counting semaphore.
+        // The last guy who was waiting sets this.
+        WaitForSingleObject(condState->waitersDone, INFINITE);
+
+        // Reset wasBroadcast.  (No crit section needed because nobody
+        // else can wake up to poke at it.)
+        condState->wasBroadcast = 0;
+    } else {
+        // nothing to do
+        LeaveCriticalSection(&condState->waitersCountLock);
+    }
+
+    // Release internal mutex.
+    ReleaseMutex(condState->internalMutex);
+}
+
+#else
+#error "condition variables not supported on this platform"
+#endif
+
+
+/*
+ * ===========================================================================
+ *      ReadWriteLock class
+ * ===========================================================================
+ */
+
+#if 0
+#pragma mark -
+#pragma mark ReadWriteLock
+#endif
+
+/*
+ * Add a reader.  Readers are nice.  They share.
+ */
+void ReadWriteLock::lockForRead()
+{
+    mLock.lock();
+    while (mNumWriters > 0) {
+        LOG(LOG_DEBUG, "thread", "+++ lockForRead: waiting\n");
+        mReadWaiter.wait(mLock);
+    }
+    assert(mNumWriters == 0);
+    mNumReaders++;
+#if defined(PRINT_RENDER_TIMES)
+    if (mNumReaders == 1)
+        mDebugTimer.start();
+#endif
+    mLock.unlock();
+}
+
+/*
+ * Try to add a reader.  If it doesn't work right away, return "false".
+ */
+bool ReadWriteLock::tryLockForRead()
+{
+    mLock.lock();
+    if (mNumWriters > 0) {
+        mLock.unlock();
+        return false;
+    }
+    assert(mNumWriters == 0);
+    mNumReaders++;
+#if defined(PRINT_RENDER_TIMES)
+    if (mNumReaders == 1)
+        mDebugTimer.start();
+#endif
+    mLock.unlock();
+    return true;
+}
+
+/*
+ * Remove a reader.
+ */
+void ReadWriteLock::unlockForRead()
+{
+    mLock.lock();
+    if (mNumReaders == 0) {
+        mLock.unlock();
+        LOG(LOG_WARN, "thread",
+            "WARNING: unlockForRead requested, but not locked\n");
+        return;
+    }
+    assert(mNumReaders > 0);
+    assert(mNumWriters == 0);
+    mNumReaders--;
+    if (mNumReaders == 0) {           // last reader?
+#if defined(PRINT_RENDER_TIMES)
+        mDebugTimer.stop();
+        printf(" rdlk held %.3f msec\n",
+            (double) mDebugTimer.durationUsecs() / 1000.0);
+#endif
+        //printf("+++ signaling writers (if any)\n");
+        mWriteWaiter.signal();      // wake one writer (if any)
+    }
+    mLock.unlock();
+}
+
+/*
+ * Add a writer.  This requires exclusive access to the object.
+ */
+void ReadWriteLock::lockForWrite()
+{
+    mLock.lock();
+    while (mNumReaders > 0 || mNumWriters > 0) {
+        LOG(LOG_DEBUG, "thread", "+++ lockForWrite: waiting\n");
+        mWriteWaiter.wait(mLock);
+    }
+    assert(mNumReaders == 0);
+    assert(mNumWriters == 0);
+    mNumWriters++;
+#if defined(PRINT_RENDER_TIMES)
+    mDebugTimer.start();
+#endif
+    mLock.unlock();
+}
+
+/*
+ * Try to add a writer.  If it doesn't work right away, return "false".
+ */
+bool ReadWriteLock::tryLockForWrite()
+{
+    mLock.lock();
+    if (mNumReaders > 0 || mNumWriters > 0) {
+        mLock.unlock();
+        return false;
+    }
+    assert(mNumReaders == 0);
+    assert(mNumWriters == 0);
+    mNumWriters++;
+#if defined(PRINT_RENDER_TIMES)
+    mDebugTimer.start();
+#endif
+    mLock.unlock();
+    return true;
+}
+
+/*
+ * Remove a writer.
+ */
+void ReadWriteLock::unlockForWrite()
+{
+    mLock.lock();
+    if (mNumWriters == 0) {
+        mLock.unlock();
+        LOG(LOG_WARN, "thread",
+            "WARNING: unlockForWrite requested, but not locked\n");
+        return;
+    }
+    assert(mNumWriters == 1);
+    mNumWriters--;
+#if defined(PRINT_RENDER_TIMES)
+    mDebugTimer.stop();
+    //printf(" wrlk held %.3f msec\n",
+    //    (double) mDebugTimer.durationUsecs() / 1000.0);
+#endif
+    mWriteWaiter.signal();         // should other writers get first dibs?
+    //printf("+++ signaling readers (if any)\n");
+    mReadWaiter.broadcast();        // wake all readers (if any)
+    mLock.unlock();
+}
+
+// ----------------------------------------------------------------------------
+
+#if 0
+#pragma mark -
+#pragma mark Thread::Thread
+#endif
+
+/*
+ * This is our thread object!
+ */
+
+Thread::Thread(bool canCallJava)
+    :   mCanCallJava(canCallJava),
+        mThread(thread_id_t(-1)),
+        mLock("Thread::mLock"),
+        mStatus(NO_ERROR),
+        mExitPending(false), mRunning(false)
+{
+}
+
+Thread::~Thread()
+{
+}
+
+status_t Thread::readyToRun()
+{
+    return NO_ERROR;
+}
+
+status_t Thread::run(const char* name, int32_t priority, size_t stack)
+{
+    Mutex::Autolock _l(mLock);
+
+    if (mRunning) {
+        // thread already started
+        return INVALID_OPERATION;
+    }
+
+    // reset status and exitPending to their default value, so we can
+    // try again after an error happened (either below, or in readyToRun())
+    mStatus = NO_ERROR;
+    mExitPending = false;
+    mThread = thread_id_t(-1);
+    
+    // hold a strong reference on ourself
+    mHoldSelf = this;
+
+    bool res;
+    if (mCanCallJava) {
+        res = createThreadEtc(_threadLoop,
+                this, name, priority, stack, &mThread);
+    } else {
+        res = androidCreateRawThreadEtc(_threadLoop,
+                this, name, priority, stack, &mThread);
+    }
+    
+    if (res == false) {
+        mStatus = UNKNOWN_ERROR;   // something happened!
+        mRunning = false;
+        mThread = thread_id_t(-1);
+    }
+    
+    if (mStatus < 0) {
+        // something happened, don't leak
+        mHoldSelf.clear();
+    }
+    
+    return mStatus;
+}
+
+int Thread::_threadLoop(void* user)
+{
+    Thread* const self = static_cast<Thread*>(user);
+    sp<Thread> strong(self->mHoldSelf);
+    wp<Thread> weak(strong);
+    self->mHoldSelf.clear();
+
+    // we're about to run...
+    self->mStatus = self->readyToRun();
+    if (self->mStatus!=NO_ERROR || self->mExitPending) {
+        // pretend the thread never started...
+        self->mExitPending = false;
+        self->mRunning = false;
+        return 0;
+    }
+    
+    // thread is running now
+    self->mRunning = true;
+
+    do {
+        bool result = self->threadLoop();
+        if (result == false || self->mExitPending) {
+            self->mExitPending = true;
+            self->mLock.lock();
+            self->mRunning = false;
+            self->mThreadExitedCondition.signal();
+            self->mLock.unlock();
+            break;
+        }
+        
+        // Release our strong reference, to let a chance to the thread
+        // to die a peaceful death.
+        strong.clear();
+        // And immediately, reacquire a strong reference for the next loop
+        strong = weak.promote();
+    } while(strong != 0);
+    
+    return 0;
+}
+
+void Thread::requestExit()
+{
+    mExitPending = true;
+}
+
+status_t Thread::requestExitAndWait()
+{
+    if (mStatus == OK) {
+
+        if (mThread == getThreadId()) {
+            LOGW(
+            "Thread (this=%p): don't call waitForExit() from this "
+            "Thread object's thread. It's a guaranteed deadlock!",
+            this);
+            return WOULD_BLOCK;
+        }
+        
+        requestExit();
+
+        Mutex::Autolock _l(mLock);
+        while (mRunning == true) {
+            mThreadExitedCondition.wait(mLock);
+        }
+        mExitPending = false;
+    }
+    return mStatus;
+}
+
+bool Thread::exitPending() const
+{
+    return mExitPending;
+}
+
+
+
+};  // namespace android