Merge "Exporting C++ headers from system/core" am: 812b7d5d52 am: f484dd3401 am: a252f11da3

am: 5a8f555e49

Change-Id: Id449aadc3b9e6e263d351ce031b1f7f7bb4672b8

1 files changed, 165 insertions, 0 deletions

diff --git a/libutils/include/utils/Condition.h b/libutils/include/utils/Condition.h
new file mode 100644
index 000000000..25a53aa23
--- /dev/null
+++ b/libutils/include/utils/Condition.h
@@ -0,0 +1,165 @@
+/*
+ * 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.
+ */
+
+#ifndef _LIBS_UTILS_CONDITION_H
+#define _LIBS_UTILS_CONDITION_H
+
+#include <limits.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <time.h>
+
+#if !defined(_WIN32)
+# include <pthread.h>
+#endif
+
+#include <utils/Errors.h>
+#include <utils/Mutex.h>
+#include <utils/Timers.h>
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+/*
+ * Condition variable class.  The implementation is system-dependent.
+ *
+ * Condition variables are paired up with mutexes.  Lock the mutex,
+ * call wait(), then either re-wait() if things aren't quite what you want,
+ * or unlock the mutex and continue.  All threads calling wait() must
+ * use the same mutex for a given Condition.
+ */
+class Condition {
+public:
+    enum {
+        PRIVATE = 0,
+        SHARED = 1
+    };
+
+    enum WakeUpType {
+        WAKE_UP_ONE = 0,
+        WAKE_UP_ALL = 1
+    };
+
+    Condition();
+    explicit Condition(int type);
+    ~Condition();
+    // Wait on the condition variable.  Lock the mutex before calling.
+    status_t wait(Mutex& mutex);
+    // same with relative timeout
+    status_t waitRelative(Mutex& mutex, nsecs_t reltime);
+    // Signal the condition variable, allowing exactly one thread to continue.
+    void signal();
+    // Signal the condition variable, allowing one or all threads to continue.
+    void signal(WakeUpType type) {
+        if (type == WAKE_UP_ONE) {
+            signal();
+        } else {
+            broadcast();
+        }
+    }
+    // Signal the condition variable, allowing all threads to continue.
+    void broadcast();
+
+private:
+#if !defined(_WIN32)
+    pthread_cond_t mCond;
+#else
+    void*   mState;
+#endif
+};
+
+// ---------------------------------------------------------------------------
+
+#if !defined(_WIN32)
+
+inline Condition::Condition() {
+    pthread_cond_init(&mCond, NULL);
+}
+inline Condition::Condition(int type) {
+    if (type == SHARED) {
+        pthread_condattr_t attr;
+        pthread_condattr_init(&attr);
+        pthread_condattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
+        pthread_cond_init(&mCond, &attr);
+        pthread_condattr_destroy(&attr);
+    } else {
+        pthread_cond_init(&mCond, NULL);
+    }
+}
+inline Condition::~Condition() {
+    pthread_cond_destroy(&mCond);
+}
+inline status_t Condition::wait(Mutex& mutex) {
+    return -pthread_cond_wait(&mCond, &mutex.mMutex);
+}
+inline status_t Condition::waitRelative(Mutex& mutex, nsecs_t reltime) {
+    struct timespec ts;
+#if defined(__linux__)
+    clock_gettime(CLOCK_REALTIME, &ts);
+#else // __APPLE__
+    // Apple doesn't support POSIX clocks.
+    struct timeval t;
+    gettimeofday(&t, NULL);
+    ts.tv_sec = t.tv_sec;
+    ts.tv_nsec = t.tv_usec*1000;
+#endif
+
+    // On 32-bit devices, tv_sec is 32-bit, but `reltime` is 64-bit.
+    int64_t reltime_sec = reltime/1000000000;
+
+    ts.tv_nsec += static_cast<long>(reltime%1000000000);
+    if (reltime_sec < INT64_MAX && ts.tv_nsec >= 1000000000) {
+        ts.tv_nsec -= 1000000000;
+        ++reltime_sec;
+    }
+
+    int64_t time_sec = ts.tv_sec;
+    if (time_sec > INT64_MAX - reltime_sec) {
+        time_sec = INT64_MAX;
+    } else {
+        time_sec += reltime_sec;
+    }
+
+    ts.tv_sec = (time_sec > LONG_MAX) ? LONG_MAX : static_cast<long>(time_sec);
+
+    return -pthread_cond_timedwait(&mCond, &mutex.mMutex, &ts);
+}
+inline void Condition::signal() {
+    /*
+     * POSIX says pthread_cond_signal wakes up "one or more" waiting threads.
+     * However bionic follows the glibc guarantee which wakes up "exactly one"
+     * waiting thread.
+     *
+     * man 3 pthread_cond_signal
+     *   pthread_cond_signal restarts one of the threads that are waiting on
+     *   the condition variable cond. If no threads are waiting on cond,
+     *   nothing happens. If several threads are waiting on cond, exactly one
+     *   is restarted, but it is not specified which.
+     */
+    pthread_cond_signal(&mCond);
+}
+inline void Condition::broadcast() {
+    pthread_cond_broadcast(&mCond);
+}
+
+#endif // !defined(_WIN32)
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+// ---------------------------------------------------------------------------
+
+#endif // _LIBS_UTILS_CONDITON_H