base/threading: restrict to set only current thread priority

base/threading/platform_thread_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/threading/platform_thread.h"
 
 #include "base/debug/alias.h"
 #include "base/debug/profiler.h"
 #include "base/logging.h"
 #include "base/threading/thread_id_name_manager.h"
@@ skipping 37 matching lines @@
   bool joinable;
   ThreadPriority priority;
 };
 
 DWORD __stdcall ThreadFunc(void* params) {
   ThreadParams* thread_params = static_cast<ThreadParams*>(params);
   PlatformThread::Delegate* delegate = thread_params->delegate;
   if (!thread_params->joinable)
     base::ThreadRestrictions::SetSingletonAllowed(false);
 
-  if (thread_params->priority != ThreadPriority::NORMAL) {
-    PlatformThread::SetThreadPriority(
-        PlatformThread::CurrentHandle(), thread_params->priority);
-  }
+  if (thread_params->priority != ThreadPriority::NORMAL)
+    PlatformThread::SetCurrentThreadPriority(thread_params->priority);
 
   // Retrieve a copy of the thread handle to use as the key in the
   // thread name mapping.
   PlatformThreadHandle::Handle platform_handle;
   BOOL did_dup = DuplicateHandle(GetCurrentProcess(),
                                 GetCurrentThread(),
                                 GetCurrentProcess(),
                                 &platform_handle,
                                 0,
                                 FALSE,
@@ skipping 159 matching lines @@
     DWORD error = GetLastError();
     debug::Alias(&error);
     debug::Alias(&result);
     CHECK(false);
   }
 
   CloseHandle(thread_handle.platform_handle());
 }
 
 // static
-void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
-                                       ThreadPriority priority) {
-  DCHECK(!handle.is_null());
-
+void PlatformThread::SetCurrentThreadPriority(ThreadPriority priority) {
   int desired_priority = THREAD_PRIORITY_ERROR_RETURN;
   switch (priority) {
     case ThreadPriority::BACKGROUND:
       desired_priority = THREAD_PRIORITY_LOWEST;
       break;
     case ThreadPriority::NORMAL:
       desired_priority = THREAD_PRIORITY_NORMAL;
       break;
     case ThreadPriority::DISPLAY:
       desired_priority = THREAD_PRIORITY_ABOVE_NORMAL;
       break;
     case ThreadPriority::REALTIME_AUDIO:
       desired_priority = THREAD_PRIORITY_TIME_CRITICAL;
       break;
     default:
       NOTREACHED() << "Unknown priority.";
       break;
   }
   DCHECK_NE(desired_priority, THREAD_PRIORITY_ERROR_RETURN);
 
 #ifndef NDEBUG
   const BOOL success =
 #endif
-      ::SetThreadPriority(handle.platform_handle(), desired_priority);
+      ::SetThreadPriority(PlatformThread::CurrentHandle().platform_handle(),
+                          desired_priority);
   DPLOG_IF(ERROR, !success) << "Failed to set thread priority to "
                             << desired_priority;
 }
 
 // static
-ThreadPriority PlatformThread::GetThreadPriority(PlatformThreadHandle handle) {
-  DCHECK(!handle.is_null());
-
-  int priority = ::GetThreadPriority(handle.platform_handle());
+ThreadPriority PlatformThread::GetCurrentThreadPriority() {
+  int priority =
+      ::GetThreadPriority(PlatformThread::CurrentHandle().platform_handle());
   switch (priority) {
     case THREAD_PRIORITY_LOWEST:
       return ThreadPriority::BACKGROUND;
     case THREAD_PRIORITY_NORMAL:
       return ThreadPriority::NORMAL;
     case THREAD_PRIORITY_ABOVE_NORMAL:
       return ThreadPriority::DISPLAY;
     case THREAD_PRIORITY_TIME_CRITICAL:
       return ThreadPriority::REALTIME_AUDIO;
     case THREAD_PRIORITY_ERROR_RETURN:
       DPCHECK(false) << "GetThreadPriority error";  // Falls through.
     default:
       NOTREACHED() << "Unexpected priority: " << priority;
       return ThreadPriority::NORMAL;
   }
 }
 
 }  // namespace base