Cleanup common POSIX functionality.

src/platform-posix.cc

Index: src/platform-posix.cc
diff --git a/src/platform-posix.cc b/src/platform-posix.cc
index 9ed02cfdb5542f12fe2e1b9ec565c52d3d0e8f2e..bd8a33fabd13e2ec5d65be929e3c4b1fcd5e5a20 100644
--- a/src/platform-posix.cc
+++ b/src/platform-posix.cc
@@ -31,6 +31,8 @@
 
 #include "platform-posix.h"
 
+#include <pthread.h>
+#include <sched.h>  // for sched_yield
 #include <unistd.h>
 #include <errno.h>
 #include <time.h>
@@ -399,6 +401,57 @@ void OS::StrNCpy(Vector<char> dest, const char* src, size_t n) {
 
 
 // ----------------------------------------------------------------------------
+// POSIX thread support.
+//
+
+void Thread::YieldCPU() {
+  sched_yield();
+}
+
+
+class POSIXMutex : public Mutex {
+ public:
+  POSIXMutex() {
+    pthread_mutexattr_t attr;
+    memset(&attr, 0, sizeof(attr));
+    int result = pthread_mutexattr_init(&attr);
+    ASSERT(result == 0);
+    result = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
+    ASSERT(result == 0);
+    result = pthread_mutex_init(&mutex_, &attr);
+    ASSERT(result == 0);
+    result = pthread_mutexattr_destroy(&attr);
+    ASSERT(result == 0);
+    USE(result);
+  }
+
+  virtual ~POSIXMutex() { pthread_mutex_destroy(&mutex_); }
+
+  virtual int Lock() { return pthread_mutex_lock(&mutex_); }
+
+  virtual int Unlock() { return pthread_mutex_unlock(&mutex_); }
+
+  virtual bool TryLock() {
+    int result = pthread_mutex_trylock(&mutex_);
+    // Return false if the lock is busy and locking failed.
+    if (result == EBUSY) {
+      return false;
+    }
+    ASSERT(result == 0);  // Verify no other errors.
+    return true;
+  }
+
+ private:
+  pthread_mutex_t mutex_;   // Pthread mutex for POSIX platforms.
+};
+
+
+Mutex* OS::CreateMutex() {
+  return new POSIXMutex();
+}
+
+
+// ----------------------------------------------------------------------------
 // POSIX socket support.
 //