Add base to the repository.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@8 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 95 insertions, 0 deletions

diff --git a/base/thread_local_storage.h b/base/thread_local_storage.h
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+++ b/base/thread_local_storage.h
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+// Copyright 2008, 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.
+
+#ifndef BASE_THREAD_LOCAL_STORAGE_H__
+#define BASE_THREAD_LOCAL_STORAGE_H__
+
+#include "base/basictypes.h"
+
+#ifdef WIN32
+typedef int TLSSlot;
+#else
+typedef pthread_key_t TLSSlot;
+#endif
+
+// Wrapper for thread local storage.  This class doesn't
+// do much except provide an API for portability later.
+class ThreadLocalStorage {
+ public:
+  // Prototype for the TLS destructor function, which can be
+  // optionally used to cleanup thread local storage on
+  // thread exit.  'value' is the data that is stored
+  // in thread local storage.
+  typedef void (*TLSDestructorFunc)(void* value);
+
+  // Allocate a TLS 'slot'.
+  // 'destructor' is a pointer to a function to perform
+  // per-thread cleanup of this object.  If set to NULL,
+  // no cleanup is done for this TLS slot.
+  // Returns an index > 0 on success, or -1 on failure.
+  static TLSSlot Alloc(TLSDestructorFunc destructor = NULL);
+
+  // Free a previously allocated TLS 'slot'.
+  // If a destructor was set for this slot, removes
+  // the destructor so that remaining threads exiting
+  // will not free data.
+  static void Free(TLSSlot slot);
+
+  // Get the thread-local value stored in slot 'slot'.
+  // Values are guaranteed to initially be zero.
+  static void* Get(TLSSlot slot);
+
+  // Set the thread-local value stored in slot 'slot' to
+  // value 'value'.
+  static void Set(TLSSlot slot, void* value);
+
+#ifdef WIN32
+  // Function called when on thread exit to call TLS
+  // destructor functions.  This function is used internally.
+  static void ThreadExit();
+
+ private:
+  // Function to lazily initialize our thread local storage.
+  static void **Initialize();
+
+ private:
+  // The maximum number of 'slots' in our thread local storage stack.
+  // For now, this is fixed.  We could either increase statically, or
+  // we could make it dynamic in the future.
+  static const int kThreadLocalStorageSize = 64;
+
+  static long tls_key_;
+  static long tls_max_;
+  static TLSDestructorFunc tls_destructors_[kThreadLocalStorageSize];
+#endif
+
+  DISALLOW_EVIL_CONSTRUCTORS(ThreadLocalStorage);
+};
+
+#endif  // BASE_THREAD_LOCAL_STORAGE_H__