Merge google-perftools r109 (the current contents of third_party/tcmalloc/vendor)

third_party/tcmalloc/chromium/src/base/spinlock_internal.h

+/* Copyright (c) 2010, Google Inc.
+ * 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.
+ *
+ * ---
+ * This file is an internal part spinlock.cc and once.cc
+ * It may not be used directly by code outside of //base.
+ */
+
+#ifndef BASE_SPINLOCK_INTERNAL_H_
+#define BASE_SPINLOCK_INTERNAL_H_
+
+#include <config.h>
+#include "base/basictypes.h"
+#include "base/atomicops.h"
+
+namespace base {
+namespace internal {
+
+// SpinLockWait() waits until it can perform one of several transitions from
+// "from" to "to".  It returns when it performs a transition where done==true.
+struct SpinLockWaitTransition {
+  int32 from;
+  int32 to;
+  bool done;
+};
+
+// Wait until *w can transition from trans[i].from to trans[i].to for some i
+// satisfying 0<=i<n && trans[i].done, atomically make the transition,
+// then return the old value of *w.   Make any other atomic tranistions
+// where !trans[i].done, but continue waiting.
+int32 SpinLockWait(volatile Atomic32 *w, int n,
+                   const SpinLockWaitTransition trans[]);
+void SpinLockWake(volatile Atomic32 *w, bool all);
+void SpinLockDelay(volatile Atomic32 *w, int32 value, int loop);
+
+} // namespace internal
+} // namespace base
+#endif