Move base to DEPS

base/lazy_instance.h

Index: base/lazy_instance.h
diff --git a/base/lazy_instance.h b/base/lazy_instance.h
deleted file mode 100644
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-// 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.
-
-// The LazyInstance<Type, Traits> class manages a single instance of Type,
-// which will be lazily created on the first time it's accessed.  This class is
-// useful for places you would normally use a function-level static, but you
-// need to have guaranteed thread-safety.  The Type constructor will only ever
-// be called once, even if two threads are racing to create the object.  Get()
-// and Pointer() will always return the same, completely initialized instance.
-// When the instance is constructed it is registered with AtExitManager.  The
-// destructor will be called on program exit.
-//
-// LazyInstance is completely thread safe, assuming that you create it safely.
-// The class was designed to be POD initialized, so it shouldn't require a
-// static constructor.  It really only makes sense to declare a LazyInstance as
-// a global variable using the LAZY_INSTANCE_INITIALIZER initializer.
-//
-// LazyInstance is similar to Singleton, except it does not have the singleton
-// property.  You can have multiple LazyInstance's of the same type, and each
-// will manage a unique instance.  It also preallocates the space for Type, as
-// to avoid allocating the Type instance on the heap.  This may help with the
-// performance of creating the instance, and reducing heap fragmentation.  This
-// requires that Type be a complete type so we can determine the size.
-//
-// Example usage:
-//   static LazyInstance<MyClass> my_instance = LAZY_INSTANCE_INITIALIZER;
-//   void SomeMethod() {
-//     my_instance.Get().SomeMethod();  // MyClass::SomeMethod()
-//
-//     MyClass* ptr = my_instance.Pointer();
-//     ptr->DoDoDo();  // MyClass::DoDoDo
-//   }
-
-#ifndef BASE_LAZY_INSTANCE_H_
-#define BASE_LAZY_INSTANCE_H_
-
-#include <new>  // For placement new.
-
-#include "base/atomicops.h"
-#include "base/base_export.h"
-#include "base/basictypes.h"
-#include "base/debug/leak_annotations.h"
-#include "base/logging.h"
-#include "base/memory/aligned_memory.h"
-#include "base/threading/thread_restrictions.h"
-
-// LazyInstance uses its own struct initializer-list style static
-// initialization, as base's LINKER_INITIALIZED requires a constructor and on
-// some compilers (notably gcc 4.4) this still ends up needing runtime
-// initialization.
-#define LAZY_INSTANCE_INITIALIZER {0}
-
-namespace base {
-
-template <typename Type>
-struct DefaultLazyInstanceTraits {
-  static const bool kRegisterOnExit = true;
-#ifndef NDEBUG
-  static const bool kAllowedToAccessOnNonjoinableThread = false;
-#endif
-
-  static Type* New(void* instance) {
-    DCHECK_EQ(reinterpret_cast<uintptr_t>(instance) & (ALIGNOF(Type) - 1), 0u)
-        << ": Bad boy, the buffer passed to placement new is not aligned!\n"
-        "This may break some stuff like SSE-based optimizations assuming the "
-        "<Type> objects are word aligned.";
-    // Use placement new to initialize our instance in our preallocated space.
-    // The parenthesis is very important here to force POD type initialization.
-    return new (instance) Type();
-  }
-  static void Delete(Type* instance) {
-    // Explicitly call the destructor.
-    instance->~Type();
-  }
-};
-
-// We pull out some of the functionality into non-templated functions, so we
-// can implement the more complicated pieces out of line in the .cc file.
-namespace internal {
-
-// Use LazyInstance<T>::Leaky for a less-verbose call-site typedef; e.g.:
-// base::LazyInstance<T>::Leaky my_leaky_lazy_instance;
-// instead of:
-// base::LazyInstance<T, base::internal::LeakyLazyInstanceTraits<T> >
-// my_leaky_lazy_instance;
-// (especially when T is MyLongTypeNameImplClientHolderFactory).
-// Only use this internal::-qualified verbose form to extend this traits class
-// (depending on its implementation details).
-template <typename Type>
-struct LeakyLazyInstanceTraits {
-  static const bool kRegisterOnExit = false;
-#ifndef NDEBUG
-  static const bool kAllowedToAccessOnNonjoinableThread = true;
-#endif
-
-  static Type* New(void* instance) {
-    ANNOTATE_SCOPED_MEMORY_LEAK;
-    return DefaultLazyInstanceTraits<Type>::New(instance);
-  }
-  static void Delete(Type* instance) {
-  }
-};
-
-// Our AtomicWord doubles as a spinlock, where a value of
-// kBeingCreatedMarker means the spinlock is being held for creation.
-static const subtle::AtomicWord kLazyInstanceStateCreating = 1;
-
-// Check if instance needs to be created. If so return true otherwise
-// if another thread has beat us, wait for instance to be created and
-// return false.
-BASE_EXPORT bool NeedsLazyInstance(subtle::AtomicWord* state);
-
-// After creating an instance, call this to register the dtor to be called
-// at program exit and to update the atomic state to hold the |new_instance|
-BASE_EXPORT void CompleteLazyInstance(subtle::AtomicWord* state,
-                                      subtle::AtomicWord new_instance,
-                                      void* lazy_instance,
-                                      void (*dtor)(void*));
-
-}  // namespace internal
-
-template <typename Type, typename Traits = DefaultLazyInstanceTraits<Type> >
-class LazyInstance {
- public:
-  // Do not define a destructor, as doing so makes LazyInstance a
-  // non-POD-struct. We don't want that because then a static initializer will
-  // be created to register the (empty) destructor with atexit() under MSVC, for
-  // example. We handle destruction of the contained Type class explicitly via
-  // the OnExit member function, where needed.
-  // ~LazyInstance() {}
-
-  // Convenience typedef to avoid having to repeat Type for leaky lazy
-  // instances.
-  typedef LazyInstance<Type, internal::LeakyLazyInstanceTraits<Type> > Leaky;
-
-  Type& Get() {
-    return *Pointer();
-  }
-
-  Type* Pointer() {
-#ifndef NDEBUG
-    // Avoid making TLS lookup on release builds.
-    if (!Traits::kAllowedToAccessOnNonjoinableThread)
-      ThreadRestrictions::AssertSingletonAllowed();
-#endif
-    // If any bit in the created mask is true, the instance has already been
-    // fully constructed.
-    static const subtle::AtomicWord kLazyInstanceCreatedMask =
-        ~internal::kLazyInstanceStateCreating;
-
-    // We will hopefully have fast access when the instance is already created.
-    // Since a thread sees private_instance_ == 0 or kLazyInstanceStateCreating
-    // at most once, the load is taken out of NeedsInstance() as a fast-path.
-    // The load has acquire memory ordering as a thread which sees
-    // private_instance_ > creating needs to acquire visibility over
-    // the associated data (private_buf_). Pairing Release_Store is in
-    // CompleteLazyInstance().
-    subtle::AtomicWord value = subtle::Acquire_Load(&private_instance_);
-    if (!(value & kLazyInstanceCreatedMask) &&
-        internal::NeedsLazyInstance(&private_instance_)) {
-      // Create the instance in the space provided by |private_buf_|.
-      value = reinterpret_cast<subtle::AtomicWord>(
-          Traits::New(private_buf_.void_data()));
-      internal::CompleteLazyInstance(&private_instance_, value, this,
-                                     Traits::kRegisterOnExit ? OnExit : NULL);
-    }
-    return instance();
-  }
-
-  bool operator==(Type* p) {
-    switch (subtle::NoBarrier_Load(&private_instance_)) {
-      case 0:
-        return p == NULL;
-      case internal::kLazyInstanceStateCreating:
-        return static_cast<void*>(p) == private_buf_.void_data();
-      default:
-        return p == instance();
-    }
-  }
-
-  // Effectively private: member data is only public to allow the linker to
-  // statically initialize it and to maintain a POD class. DO NOT USE FROM
-  // OUTSIDE THIS CLASS.
-
-  subtle::AtomicWord private_instance_;
-  // Preallocated space for the Type instance.
-  base::AlignedMemory<sizeof(Type), ALIGNOF(Type)> private_buf_;
-
- private:
-  Type* instance() {
-    return reinterpret_cast<Type*>(subtle::NoBarrier_Load(&private_instance_));
-  }
-
-  // Adapter function for use with AtExit.  This should be called single
-  // threaded, so don't synchronize across threads.
-  // Calling OnExit while the instance is in use by other threads is a mistake.
-  static void OnExit(void* lazy_instance) {
-    LazyInstance<Type, Traits>* me =
-        reinterpret_cast<LazyInstance<Type, Traits>*>(lazy_instance);
-    Traits::Delete(me->instance());
-    subtle::NoBarrier_Store(&me->private_instance_, 0);
-  }
-};
-
-}  // namespace base
-
-#endif  // BASE_LAZY_INSTANCE_H_