Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 225 insertions, 0 deletions

diff --git a/mfbt/Scoped.h b/mfbt/Scoped.h
new file mode 100644
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+++ b/mfbt/Scoped.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* DEPRECATED: Use UniquePtr.h instead. */
+
+#ifndef mozilla_Scoped_h
+#define mozilla_Scoped_h
+
+/*
+ * DEPRECATED: Use UniquePtr.h instead.
+ *
+ * Resource Acquisition Is Initialization is a programming idiom used
+ * to write robust code that is able to deallocate resources properly,
+ * even in presence of execution errors or exceptions that need to be
+ * propagated.  The Scoped* classes defined via the |SCOPED_TEMPLATE|
+ * and |MOZ_TYPE_SPECIFIC_SCOPED_POINTER_TEMPLTE| macros perform the
+ * deallocation of the resource they hold once program execution
+ * reaches the end of the scope for which they have been defined.
+ * These macros have been used to automatically close file
+ * descriptors/file handles when reaching the end of the scope,
+ * graphics contexts, etc.
+ *
+ * The general scenario for RAII classes created by the above macros
+ * is the following:
+ *
+ * ScopedClass foo(create_value());
+ * // ... In this scope, |foo| is defined. Use |foo.get()| or |foo.rwget()|
+ *        to access the value.
+ * // ... In case of |return| or |throw|, |foo| is deallocated automatically.
+ * // ... If |foo| needs to be returned or stored, use |foo.forget()|
+ *
+ * Note that the RAII classes defined in this header do _not_ perform any form
+ * of reference-counting or garbage-collection. These classes have exactly two
+ * behaviors:
+ *
+ * - if |forget()| has not been called, the resource is always deallocated at
+ *   the end of the scope;
+ * - if |forget()| has been called, any control on the resource is unbound
+ *   and the resource is not deallocated by the class.
+ */
+
+#include <utility>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+
+namespace mozilla {
+
+/*
+ * Scoped is a helper to create RAII wrappers
+ * Type argument |Traits| is expected to have the following structure:
+ *
+ *   struct Traits
+ *   {
+ *     // Define the type of the value stored in the wrapper
+ *     typedef value_type type;
+ *     // Returns the value corresponding to the uninitialized or freed state
+ *     const static type empty();
+ *     // Release resources corresponding to the wrapped value
+ *     // This function is responsible for not releasing an |empty| value
+ *     const static void release(type);
+ *   }
+ */
+template <typename Traits>
+class MOZ_NON_TEMPORARY_CLASS Scoped {
+ public:
+  typedef typename Traits::type Resource;
+
+  explicit Scoped() : mValue(Traits::empty()) {}
+
+  explicit Scoped(const Resource& aValue) : mValue(aValue) {}
+
+  /* Move constructor. */
+  Scoped(Scoped&& aOther) : mValue(std::move(aOther.mValue)) {
+    aOther.mValue = Traits::empty();
+  }
+
+  ~Scoped() { Traits::release(mValue); }
+
+  // Constant getter
+  operator const Resource&() const { return mValue; }
+  const Resource& operator->() const { return mValue; }
+  const Resource& get() const { return mValue; }
+  // Non-constant getter.
+  Resource& rwget() { return mValue; }
+
+  /*
+   * Forget the resource.
+   *
+   * Once |forget| has been called, the |Scoped| is neutralized, i.e. it will
+   * have no effect at destruction (unless it is reset to another resource by
+   * |operator=|).
+   *
+   * @return The original resource.
+   */
+  Resource forget() {
+    Resource tmp = mValue;
+    mValue = Traits::empty();
+    return tmp;
+  }
+
+  /*
+   * Perform immediate clean-up of this |Scoped|.
+   *
+   * If this |Scoped| is currently empty, this method has no effect.
+   */
+  void dispose() {
+    Traits::release(mValue);
+    mValue = Traits::empty();
+  }
+
+  bool operator==(const Resource& aOther) const { return mValue == aOther; }
+
+  /*
+   * Replace the resource with another resource.
+   *
+   * Calling |operator=| has the side-effect of triggering clean-up. If you do
+   * not want to trigger clean-up, you should first invoke |forget|.
+   *
+   * @return this
+   */
+  Scoped& operator=(const Resource& aOther) { return reset(aOther); }
+
+  Scoped& reset(const Resource& aOther) {
+    Traits::release(mValue);
+    mValue = aOther;
+    return *this;
+  }
+
+  /* Move assignment operator. */
+  Scoped& operator=(Scoped&& aRhs) {
+    MOZ_ASSERT(&aRhs != this, "self-move-assignment not allowed");
+    this->~Scoped();
+    new (this) Scoped(std::move(aRhs));
+    return *this;
+  }
+
+ private:
+  explicit Scoped(const Scoped& aValue) = delete;
+  Scoped& operator=(const Scoped& aValue) = delete;
+
+ private:
+  Resource mValue;
+};
+
+/*
+ * SCOPED_TEMPLATE defines a templated class derived from Scoped
+ * This allows to implement templates such as ScopedFreePtr.
+ *
+ * @param name The name of the class to define.
+ * @param Traits A struct implementing clean-up. See the implementations
+ * for more details.
+ */
+#define SCOPED_TEMPLATE(name, Traits)             \
+  template <typename Type>                        \
+  struct MOZ_NON_TEMPORARY_CLASS name             \
+      : public mozilla::Scoped<Traits<Type> > {   \
+    typedef mozilla::Scoped<Traits<Type> > Super; \
+    typedef typename Super::Resource Resource;    \
+    name& operator=(Resource aRhs) {              \
+      Super::operator=(aRhs);                     \
+      return *this;                               \
+    }                                             \
+    name& operator=(name&& aRhs) = default;       \
+                                                  \
+    explicit name() : Super() {}                  \
+    explicit name(Resource aRhs) : Super(aRhs) {} \
+    name(name&& aRhs) : Super(std::move(aRhs)) {} \
+                                                  \
+   private:                                       \
+    explicit name(const name&) = delete;          \
+    name& operator=(const name&) = delete;        \
+  };
+
+/*
+ * MOZ_TYPE_SPECIFIC_SCOPED_POINTER_TEMPLATE makes it easy to create scoped
+ * pointers for types with custom deleters; just overload
+ * TypeSpecificDelete(T*) in the same namespace as T to call the deleter for
+ * type T.
+ *
+ * @param name The name of the class to define.
+ * @param Type A struct implementing clean-up. See the implementations
+ * for more details.
+ * *param Deleter The function that is used to delete/destroy/free a
+ *        non-null value of Type*.
+ *
+ * Example:
+ *
+ *   MOZ_TYPE_SPECIFIC_SCOPED_POINTER_TEMPLATE(ScopedPRFileDesc, PRFileDesc, \
+ *                                             PR_Close)
+ *   ...
+ *   {
+ *       ScopedPRFileDesc file(PR_OpenFile(...));
+ *       ...
+ *   } // file is closed with PR_Close here
+ */
+#define MOZ_TYPE_SPECIFIC_SCOPED_POINTER_TEMPLATE(name, Type, Deleter) \
+  template <>                                                          \
+  inline void TypeSpecificDelete(Type* aValue) {                       \
+    Deleter(aValue);                                                   \
+  }                                                                    \
+  typedef ::mozilla::TypeSpecificScopedPointer<Type> name;
+
+template <typename T>
+void TypeSpecificDelete(T* aValue);
+
+template <typename T>
+struct TypeSpecificScopedPointerTraits {
+  typedef T* type;
+  static type empty() { return nullptr; }
+  static void release(type aValue) {
+    if (aValue) {
+      TypeSpecificDelete(aValue);
+    }
+  }
+};
+
+SCOPED_TEMPLATE(TypeSpecificScopedPointer, TypeSpecificScopedPointerTraits)
+
+} /* namespace mozilla */
+
+#endif /* mozilla_Scoped_h */