implement Mutex and Condition with pthread instead of calling futex directly.

internally pthread uses futex. the implementation consists of simple inlines
there are no implementation files anymore.

3 files changed, 6 insertions, 474 deletions

diff --git a/libs/utils/Android.mk b/libs/utils/Android.mk
index 3f5cb85..59409a2 100644
--- a/libs/utils/Android.mk
+++ b/libs/utils/Android.mk
@@ -51,13 +51,6 @@ include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES:= $(commonSources)
 
-ifeq ($(HOST_OS),linux)
-# Use the futex based mutex and condition variable
-# implementation from android-arm because it's shared mem safe
-	LOCAL_SRC_FILES += \
-		futex_synchro.c
-endif
-
 LOCAL_MODULE:= libutils
 
 LOCAL_CFLAGS += -DLIBUTILS_NATIVE=1 $(TOOL_CFLAGS)
@@ -87,15 +80,13 @@ LOCAL_SRC_FILES:= \
 	BackupHelpers.cpp
 
 ifeq ($(TARGET_OS),linux)
-# Use the futex based mutex and condition variable
-# implementation from android-arm because it's shared mem safe
-LOCAL_SRC_FILES += futex_synchro.c
 LOCAL_LDLIBS += -lrt -ldl
 endif
 
 LOCAL_C_INCLUDES += \
 		external/zlib \
 		external/icu4c/common
+
 LOCAL_LDLIBS += -lpthread
 
 LOCAL_SHARED_LIBRARIES := \
@@ -106,8 +97,7 @@ LOCAL_SHARED_LIBRARIES := \
 ifneq ($(TARGET_SIMULATOR),true)
 ifeq ($(TARGET_OS)-$(TARGET_ARCH),linux-x86)
 # This is needed on x86 to bring in dl_iterate_phdr for CallStack.cpp
-LOCAL_SHARED_LIBRARIES += \
-	libdl
+LOCAL_SHARED_LIBRARIES += libdl
 endif # linux-x86
 endif # sim
 
diff --git a/libs/utils/Threads.cpp b/libs/utils/Threads.cpp
index 9287c0b..4036c49 100644
--- a/libs/utils/Threads.cpp
+++ b/libs/utils/Threads.cpp
@@ -38,10 +38,6 @@
 # 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
@@ -56,10 +52,6 @@ using namespace android;
 
 // ----------------------------------------------------------------------------
 #if defined(HAVE_PTHREADS)
-#if 0
-#pragma mark -
-#pragma mark PTHREAD
-#endif
 // ----------------------------------------------------------------------------
 
 /*
@@ -163,10 +155,6 @@ android_thread_id_t androidGetThreadId()
 
 // ----------------------------------------------------------------------------
 #elif defined(HAVE_WIN32_THREADS)
-#if 0
-#pragma mark -
-#pragma mark WIN32_THREADS
-#endif
 // ----------------------------------------------------------------------------
 
 /*
@@ -252,11 +240,6 @@ android_thread_id_t androidGetThreadId()
 
 // ----------------------------------------------------------------------------
 
-#if 0
-#pragma mark -
-#pragma mark Common Thread functions
-#endif
-
 int androidCreateThread(android_thread_func_t fn, void* arg)
 {
     return createThreadEtc(fn, arg);
@@ -294,109 +277,9 @@ namespace android {
  * ===========================================================================
  */
 
-#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
-
+#if defined(HAVE_PTHREADS)
+// implemented as inlines in threads.h
 #elif defined(HAVE_WIN32_THREADS)
-#if 0
-#pragma mark -
-#endif
 
 Mutex::Mutex()
 {
@@ -456,161 +339,9 @@ status_t Mutex::tryLock()
  * ===========================================================================
  */
 
-#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
-
+#if defined(HAVE_PTHREADS)
+// implemented as inlines in threads.h
 #elif defined(HAVE_WIN32_THREADS)
-#if 0
-#pragma mark -
-#endif
 
 /*
  * Windows doesn't have a condition variable solution.  It's possible
@@ -753,14 +484,6 @@ status_t Condition::wait(Mutex& mutex)
     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);
@@ -841,11 +564,6 @@ void Condition::broadcast()
 
 // ----------------------------------------------------------------------------
 
-#if 0
-#pragma mark -
-#pragma mark Thread::Thread
-#endif
-
 /*
  * This is our thread object!
  */
diff --git a/libs/utils/futex_synchro.c b/libs/utils/futex_synchro.c
deleted file mode 100644
index ab48c69..0000000
--- a/libs/utils/futex_synchro.c
+++ /dev/null
@@ -1,176 +0,0 @@
-/*
- * Copyright (C) 2008 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 <stdio.h>
-#include <limits.h>
-
-#include <sys/time.h>
-#include <sched.h>
-
-#include <errno.h>
-
-#include <private/utils/futex_synchro.h>
-
-
-// This futex glue code is need on desktop linux, but is already part of bionic.
-#if !defined(HAVE_FUTEX_WRAPPERS)
-
-#include <unistd.h>
-#include <sys/syscall.h>
-typedef unsigned int u32;
-#define asmlinkage
-#define __user
-#include <linux/futex.h>
-#include <utils/Atomic.h>
-
-
-int futex (int *uaddr, int op, int val, const struct timespec *timeout, int *uaddr2, int val3)
-{
-    int err = syscall(SYS_futex, uaddr, op, val, timeout, uaddr2, val3);
-    return err == 0 ? 0 : -errno;
-}
-
-int __futex_wait(volatile void *ftx, int val, const struct timespec *timeout)
-{
-    return futex((int*)ftx, FUTEX_WAIT, val, timeout, NULL, 0);
-}
-
-int __futex_wake(volatile void *ftx, int count)
-{
-    return futex((int*)ftx, FUTEX_WAKE, count, NULL, NULL, 0);
-}
-
-int __atomic_cmpxchg(int old, int _new, volatile int *ptr)
-{
-    return android_atomic_cmpxchg(old, _new, ptr);
-}
-
-int __atomic_swap(int _new, volatile int *ptr)
-{
-    return android_atomic_swap(_new, ptr);
-}
-
-int __atomic_dec(volatile int *ptr)
-{
-    return android_atomic_dec(ptr);
-}
-
-#else // !defined(__arm__)
-
-int __futex_wait(volatile void *ftx, int val, const struct timespec *timeout);
-int __futex_wake(volatile void *ftx, int count);
-
-int __atomic_cmpxchg(int old, int _new, volatile int *ptr);
-int __atomic_swap(int _new, volatile int *ptr);
-int __atomic_dec(volatile int *ptr);
-
-#endif // !defined(HAVE_FUTEX_WRAPPERS)
-
-
-// lock states
-//
-// 0: unlocked
-// 1: locked, no waiters
-// 2: locked, maybe waiters
-
-void futex_mutex_init(futex_mutex_t *m)
-{
-    m->value = 0;
-}
-
-int futex_mutex_lock(futex_mutex_t *m, unsigned msec)
-{
-    if(__atomic_cmpxchg(0, 1, &m->value) == 0) {
-        return 0;
-    }
-    if(msec == FUTEX_WAIT_INFINITE) {
-        while(__atomic_swap(2, &m->value) != 0) {
-            __futex_wait(&m->value, 2, 0);
-        }
-    } else {
-        struct timespec ts;
-        ts.tv_sec = msec / 1000;
-        ts.tv_nsec = (msec % 1000) * 1000000;
-        while(__atomic_swap(2, &m->value) != 0) {
-            if(__futex_wait(&m->value, 2, &ts) == -ETIMEDOUT) {
-                return -1;
-            }
-        }
-    }
-    return 0;
-}
-
-int futex_mutex_trylock(futex_mutex_t *m)
-{
-    if(__atomic_cmpxchg(0, 1, &m->value) == 0) {
-        return 0;
-    }
-    return -1;
-}
-
-void futex_mutex_unlock(futex_mutex_t *m)
-{
-    if(__atomic_dec(&m->value) != 1) {
-        m->value = 0;
-        __futex_wake(&m->value, 1);
-    }
-}
-
-/* XXX *technically* there is a race condition that could allow
- * XXX a signal to be missed.  If thread A is preempted in _wait()
- * XXX after unlocking the mutex and before waiting, and if other
- * XXX threads call signal or broadcast UINT_MAX times (exactly),
- * XXX before thread A is scheduled again and calls futex_wait(),
- * XXX then the signal will be lost.
- */
-
-void futex_cond_init(futex_cond_t *c)
-{
-    c->value = 0;
-}
-
-int futex_cond_wait(futex_cond_t *c, futex_mutex_t *m, unsigned msec)
-{
-    if(msec == FUTEX_WAIT_INFINITE){
-        int oldvalue = c->value;
-        futex_mutex_unlock(m);
-        __futex_wait(&c->value, oldvalue, 0);
-        futex_mutex_lock(m, FUTEX_WAIT_INFINITE);
-        return 0;
-    } else {
-        int oldvalue = c->value;
-        struct timespec ts;        
-        ts.tv_sec = msec / 1000;
-        ts.tv_nsec = (msec % 1000) * 1000000;
-        futex_mutex_unlock(m);
-        const int err = __futex_wait(&c->value, oldvalue, &ts);
-        futex_mutex_lock(m, FUTEX_WAIT_INFINITE);
-        return err;
-    }
-}
-
-void futex_cond_signal(futex_cond_t *c)
-{
-    __atomic_dec(&c->value);
-    __futex_wake(&c->value, 1);
-}
-
-void futex_cond_broadcast(futex_cond_t *c)
-{
-    __atomic_dec(&c->value);
-    __futex_wake(&c->value, INT_MAX);
-}
-