Added a new method CreateNonJoinable() to PlatformThread. Added the windows and posix implementations.

Review URL: http://codereview.chromium.org/40133

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@11053 0039d316-1c4b-4281-b951-d872f2087c98

base/platform_thread.h

@@ -65,6 +65,11 @@ class PlatformThread {
   static bool Create(size_t stack_size, Delegate* delegate,
                      PlatformThreadHandle* thread_handle);
 
+  // CreateNonJoinable() does the same thing as Create() except the thread
+  // cannot be Join()'d.  Therefore, it also does not output a
+  // PlatformThreadHandle.
+  static bool CreateNonJoinable(size_t stack_size, Delegate* delegate);
+
   // Joins with a thread created via the Create function.  This function blocks
   // the caller until the designated thread exits.  This will invalidate
   // |thread_handle|.
@@ -75,4 +80,3 @@ class PlatformThread {
 };
 
 #endif  // BASE_PLATFORM_THREAD_H_
-

base/platform_thread_posix.cc

@@ -68,9 +68,11 @@ void PlatformThread::SetName(const char* name) {
   // structure would be useful for debugging or not.
 }
 
-// static
-bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
-                            PlatformThreadHandle* thread_handle) {
+namespace {
+
+bool CreateThread(size_t stack_size, bool joinable,
+                  PlatformThread::Delegate* delegate,
+                  PlatformThreadHandle* thread_handle) {
 #if defined(OS_MACOSX)
   base::InitThreading();
 #endif  // OS_MACOSX
@@ -79,8 +81,11 @@ bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
   pthread_attr_t attributes;
   pthread_attr_init(&attributes);
 
-  // Pthreads are joinable by default, so we don't need to specify any special
-  // attributes to be able to call pthread_join later.
+  // Pthreads are joinable by default, so only specify the detached attribute if
+  // the thread should be non-joinable.
+  if (!joinable) {
+    pthread_attr_setdetachstate(&attributes, PTHREAD_CREATE_DETACHED);
+  }
 
   if (stack_size > 0)
     pthread_attr_setstacksize(&attributes, stack_size);
@@ -91,6 +96,24 @@ bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
   return success;
 }
 
+}  // anonymous namespace
+
+// static
+bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
+                            PlatformThreadHandle* thread_handle) {
+  return CreateThread(stack_size, true /* joinable thread */,
+                      delegate, thread_handle);
+}
+
+// static
+bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) {
+  PlatformThreadHandle unused;
+
+  bool result = CreateThread(stack_size, false /* non-joinable thread */,
+                             delegate, &unused);
+  return result;
+}
+
 // static
 void PlatformThread::Join(PlatformThreadHandle thread_handle) {
   pthread_join(thread_handle, NULL);

base/platform_thread_win.cc

@@ -84,6 +84,14 @@ bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
   return *thread_handle != NULL;
 }
 
+// static
+bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) {
+  PlatformThreadHandle thread_handle;
+  bool result = Create(stack_size, delegate, &thread_handle);
+  CloseHandle(thread_handle);
+  return result;
+}
+
 // static
 void PlatformThread::Join(PlatformThreadHandle thread_handle) {
   DCHECK(thread_handle);