// Copyright (c) 2014 Marshall A. Greenblatt. Portions copyright (c) 2012
// 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 name Chromium Embedded
// Framework 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 CEF_INCLUDE_BASE_CEF_CALLBACK_H_
#define CEF_INCLUDE_BASE_CEF_CALLBACK_H_
#pragma once

#if defined(BASE_CALLBACK_H_)
// Do nothing if the Chromium header has already been included.
// This can happen in cases where Chromium code is used directly by the
// client application. When using Chromium code directly always include
// the Chromium header first to avoid type conflicts.
#elif defined(USING_CHROMIUM_INCLUDES)
// When building CEF include the Chromium header directly.
#include "base/callback.h"
#else  // !USING_CHROMIUM_INCLUDES
// The following is substantially similar to the Chromium implementation.
// If the Chromium implementation diverges the below implementation should be
// updated to match.

#include "include/base/internal/cef_callback_internal.h"
#include "include/base/cef_callback_forward.h"
#include "include/base/cef_template_util.h"

// NOTE: Header files that do not require the full definition of Callback or
// Closure should #include "base/cef_callback_forward.h" instead of this file.

// -----------------------------------------------------------------------------
// Introduction
// -----------------------------------------------------------------------------
//
// The templated Callback class is a generalized function object. Together
// with the Bind() function in bind.h, they provide a type-safe method for
// performing partial application of functions.
//
// Partial application (or "currying") is the process of binding a subset of
// a function's arguments to produce another function that takes fewer
// arguments. This can be used to pass around a unit of delayed execution,
// much like lexical closures are used in other languages. For example, it
// is used in Chromium code to schedule tasks on different MessageLoops.
//
// A callback with no unbound input parameters (base::Callback)
// is called a base::Closure. Note that this is NOT the same as what other
// languages refer to as a closure -- it does not retain a reference to its
// enclosing environment.
//
// MEMORY MANAGEMENT AND PASSING
//
// The Callback objects themselves should be passed by const-reference, and
// stored by copy. They internally store their state via a refcounted class
// and thus do not need to be deleted.
//
// The reason to pass via a const-reference is to avoid unnecessary
// AddRef/Release pairs to the internal state.
//
//
// -----------------------------------------------------------------------------
// Quick reference for basic stuff
// -----------------------------------------------------------------------------
//
// BINDING A BARE FUNCTION
//
//   int Return5() { return 5; }
//   base::Callback func_cb = base::Bind(&Return5);
//   LOG(INFO)