deanm@chromium.org
98149e5a43
Normalize end of file newlines in base/. All files end in a single newline. Review URL: http://codereview.chromium.org/42011 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@11329 0039d316-1c4b-4281-b951-d872f2087c98
95 linhas
2.8 KiB
C++
95 linhas
2.8 KiB
C++
// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_THREAD_LOCAL_STORAGE_H_
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#define BASE_THREAD_LOCAL_STORAGE_H_
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#include "base/basictypes.h"
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#if defined(OS_POSIX)
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#include <pthread.h>
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#endif
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// Wrapper for thread local storage. This class doesn't do much except provide
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// an API for portability.
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class ThreadLocalStorage {
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public:
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// Prototype for the TLS destructor function, which can be optionally used to
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// cleanup thread local storage on thread exit. 'value' is the data that is
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// stored in thread local storage.
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typedef void (*TLSDestructorFunc)(void* value);
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// A key representing one value stored in TLS.
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class Slot {
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public:
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Slot(TLSDestructorFunc destructor = NULL);
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// This constructor should be used for statics.
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// It returns an uninitialized Slot.
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explicit Slot(base::LinkerInitialized x) {}
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// Set up the TLS slot. Called by the constructor.
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// 'destructor' is a pointer to a function to perform per-thread cleanup of
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// this object. If set to NULL, no cleanup is done for this TLS slot.
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// Returns false on error.
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bool Initialize(TLSDestructorFunc destructor);
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// Free a previously allocated TLS 'slot'.
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// If a destructor was set for this slot, removes
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// the destructor so that remaining threads exiting
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// will not free data.
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void Free();
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// Get the thread-local value stored in slot 'slot'.
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// Values are guaranteed to initially be zero.
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void* Get() const;
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// Set the thread-local value stored in slot 'slot' to
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// value 'value'.
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void Set(void* value);
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bool initialized() const { return initialized_; }
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private:
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// The internals of this struct should be considered private.
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bool initialized_;
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#if defined(OS_WIN)
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int slot_;
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#elif defined(OS_POSIX)
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pthread_key_t key_;
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#endif
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DISALLOW_COPY_AND_ASSIGN(Slot);
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};
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#if defined(OS_WIN)
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// Function called when on thread exit to call TLS
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// destructor functions. This function is used internally.
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static void ThreadExit();
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private:
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// Function to lazily initialize our thread local storage.
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static void **Initialize();
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private:
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// The maximum number of 'slots' in our thread local storage stack.
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// For now, this is fixed. We could either increase statically, or
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// we could make it dynamic in the future.
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static const int kThreadLocalStorageSize = 64;
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static long tls_key_;
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static long tls_max_;
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static TLSDestructorFunc tls_destructors_[kThreadLocalStorageSize];
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#endif // OS_WIN
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DISALLOW_COPY_AND_ASSIGN(ThreadLocalStorage);
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};
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// Temporary backwards-compatible name.
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// TODO(evanm): replace all usage of TLSSlot.
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typedef ThreadLocalStorage::Slot TLSSlot;
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#endif // BASE_THREAD_LOCAL_STORAGE_H_
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