Repo created

TMessagesProj/jni/voip/webrtc/base/bind_helpers.h

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+// Copyright (c) 2011 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.
+
+#ifndef BASE_BIND_HELPERS_H_
+#define BASE_BIND_HELPERS_H_
+
+#include <stddef.h>
+
+#include <type_traits>
+#include <utility>
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "build/build_config.h"
+
+// This defines a set of simple functions and utilities that people want when
+// using {Once,Repeating}Callback<> and Bind{Once,Repeating}().
+
+namespace base {
+
+// Creates a null callback.
+class BASE_EXPORT NullCallback {
+ public:
+  template <typename R, typename... Args>
+  operator RepeatingCallback<R(Args...)>() const {
+    return RepeatingCallback<R(Args...)>();
+  }
+  template <typename R, typename... Args>
+  operator OnceCallback<R(Args...)>() const {
+    return OnceCallback<R(Args...)>();
+  }
+};
+
+// Creates a callback that does nothing when called.
+class BASE_EXPORT DoNothing {
+ public:
+  template <typename... Args>
+  operator RepeatingCallback<void(Args...)>() const {
+    return Repeatedly<Args...>();
+  }
+  template <typename... Args>
+  operator OnceCallback<void(Args...)>() const {
+    return Once<Args...>();
+  }
+  // Explicit way of specifying a specific callback type when the compiler can't
+  // deduce it.
+  template <typename... Args>
+  static RepeatingCallback<void(Args...)> Repeatedly() {
+    return BindRepeating([](Args... args) {});
+  }
+  template <typename... Args>
+  static OnceCallback<void(Args...)> Once() {
+    return BindOnce([](Args... args) {});
+  }
+};
+
+// Useful for creating a Closure that will delete a pointer when invoked. Only
+// use this when necessary. In most cases MessageLoop::DeleteSoon() is a better
+// fit.
+template <typename T>
+void DeletePointer(T* obj) {
+  delete obj;
+}
+
+}  // namespace base
+
+#endif  // BASE_BIND_HELPERS_H_