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Unified Diff: src/once.cc

Issue 9666052: Landing for pliard@chromium.org: Remove static initializers in v8. (Closed) Base URL: http://v8.googlecode.com/svn/branches/bleeding_edge/
Patch Set: Created 8 years, 9 months ago
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Index: src/once.cc
===================================================================
--- src/once.cc (revision 0)
+++ src/once.cc (revision 0)
@@ -0,0 +1,77 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "once.h"
+
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <sched.h>
+#endif
+
+#include "atomicops.h"
+#include "checks.h"
+
+namespace v8 {
+namespace internal {
+
+void CallOnceImpl(OnceType* once, PointerArgFunction init_func, void* arg) {
+ AtomicWord state = Acquire_Load(once);
+ // Fast path. The provided function was already executed.
+ if (state == ONCE_STATE_DONE) {
+ return;
+ }
+
+ // The function execution did not complete yet. The once object can be in one
+ // of the two following states:
+ // - UNINITIALIZED: We are the first thread calling this function.
+ // - EXECUTING_FUNCTION: Another thread is already executing the function.
+ //
+ // First, try to change the state from UNINITIALIZED to EXECUTING_FUNCTION
+ // atomically.
+ state = Acquire_CompareAndSwap(
+ once, ONCE_STATE_UNINITIALIZED, ONCE_STATE_EXECUTING_FUNCTION);
+ if (state == ONCE_STATE_UNINITIALIZED) {
+ // We are the first thread to call this function, so we have to call the
+ // function.
+ init_func(arg);
+ Release_Store(once, ONCE_STATE_DONE);
+ } else {
+ // Another thread has already started executing the function. We need to
+ // wait until it completes the initialization.
+ while (state == ONCE_STATE_EXECUTING_FUNCTION) {
+#ifdef _WIN32
+ ::Sleep(0);
+#else
+ sched_yield();
+#endif
+ state = Acquire_Load(once);
+ }
+ }
+}
+
+} } // namespace v8::internal
Property changes on: src/once.cc
___________________________________________________________________
Added: svn:eol-style
+ LF
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