Mutex: add timedLock() method

This is not available for host builds because OSX doesn't have
pthread_mutex_timedlock() or equivalent.

Bug: 18842510
Change-Id: I072e74ab1a6f770fd245828b39c5f954dda1113b

1 files changed, 24 insertions, 4 deletions

diff --git a/include/utils/Mutex.h b/include/utils/Mutex.h
index dd201c8..4fdd27f 100644
--- a/include/utils/Mutex.h
+++ b/include/utils/Mutex.h
@@ -26,6 +26,7 @@
 #endif
 
 #include <utils/Errors.h>
+#include <utils/Timers.h>
 
 // ---------------------------------------------------------------------------
 namespace android {
@@ -45,7 +46,7 @@ public:
         PRIVATE = 0,
         SHARED = 1
     };
-    
+
                 Mutex();
                 Mutex(const char* name);
                 Mutex(int type, const char* name = NULL);
@@ -58,6 +59,16 @@ public:
     // lock if possible; returns 0 on success, error otherwise
     status_t    tryLock();
 
+#if HAVE_ANDROID_OS
+    // lock the mutex, but don't wait longer than timeoutMilliseconds.
+    // Returns 0 on success, TIMED_OUT for failure due to timeout expiration.
+    //
+    // OSX doesn't have pthread_mutex_timedlock() or equivalent. To keep
+    // capabilities consistent across host OSes, this method is only available
+    // when building Android binaries.
+    status_t    timedLock(nsecs_t timeoutMilliseconds);
+#endif
+
     // Manages the mutex automatically. It'll be locked when Autolock is
     // constructed and released when Autolock goes out of scope.
     class Autolock {
@@ -71,11 +82,11 @@ public:
 
 private:
     friend class Condition;
-    
+
     // A mutex cannot be copied
                 Mutex(const Mutex&);
     Mutex&      operator = (const Mutex&);
-    
+
 #if defined(HAVE_PTHREADS)
     pthread_mutex_t mMutex;
 #else
@@ -117,6 +128,15 @@ inline void Mutex::unlock() {
 inline status_t Mutex::tryLock() {
     return -pthread_mutex_trylock(&mMutex);
 }
+#if HAVE_ANDROID_OS
+inline status_t Mutex::timedLock(nsecs_t timeoutNs) {
+    const struct timespec ts = {
+        /* .tv_sec = */ timeoutNs / 1000000000,
+        /* .tv_nsec = */ timeoutNs % 1000000000,
+    };
+    return -pthread_mutex_timedlock(&mMutex, &ts);
+}
+#endif
 
 #endif // HAVE_PTHREADS
 
@@ -127,7 +147,7 @@ inline status_t Mutex::tryLock() {
  * When the function returns, it will go out of scope, and release the
  * mutex.
  */
- 
+
 typedef Mutex::Autolock AutoMutex;
 
 // ---------------------------------------------------------------------------