Move webrtc/{base => rtc_base}

webrtc/base/callback.h.pump

-/*
- *  Copyright 2012 The WebRTC Project Authors. All rights reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-// To generate callback.h from callback.h.pump, execute:
-// /home/build/google3/third_party/gtest/scripts/pump.py callback.h.pump
-
-// Callbacks are callable object containers. They can hold a function pointer
-// or a function object and behave like a value type. Internally, data is
-// reference-counted, making copies and pass-by-value inexpensive.
-//
-// Callbacks are typed using template arguments.  The format is:
-//   CallbackN<ReturnType, ParamType1, ..., ParamTypeN>
-// where N is the number of arguments supplied to the callable object.
-// Callbacks are invoked using operator(), just like a function or a function
-// object. Default-constructed callbacks are "empty," and executing an empty
-// callback does nothing. A callback can be made empty by assigning it from
-// a default-constructed callback.
-//
-// Callbacks are similar in purpose to std::function (which isn't available on
-// all platforms we support) and a lightweight alternative to sigslots. Since
-// they effectively hide the type of the object they call, they're useful in
-// breaking dependencies between objects that need to interact with one another.
-// Notably, they can hold the results of Bind(), std::bind*, etc, without needing
-// to know the resulting object type of those calls.
-//
-// Sigslots, on the other hand, provide a fuller feature set, such as multiple
-// subscriptions to a signal, optional thread-safety, and lifetime tracking of
-// slots. When these features are needed, choose sigslots.
-//
-// Example:
-//   int sqr(int x) { return x * x; }
-//   struct AddK {
-//     int k;
-//     int operator()(int x) const { return x + k; }
-//   } add_k = {5};
-//
-//   Callback1<int, int> my_callback;
-//   cout << my_callback.empty() << endl;  // true
-//
-//   my_callback = Callback1<int, int>(&sqr);
-//   cout << my_callback.empty() << endl;  // false
-//   cout << my_callback(3) << endl;  // 9
-//
-//   my_callback = Callback1<int, int>(add_k);
-//   cout << my_callback(10) << endl;  // 15
-//
-//   my_callback = Callback1<int, int>();
-//   cout << my_callback.empty() << endl;  // true
-
-#ifndef WEBRTC_BASE_CALLBACK_H_
-#define WEBRTC_BASE_CALLBACK_H_
-
-#include "webrtc/base/refcount.h"
-#include "webrtc/base/scoped_ref_ptr.h"
-
-namespace rtc {
-
-$var n = 5
-$range i 0..n
-$for i [[
-$range j 1..i
-
-template <class R$for j [[,
-          class P$j]]>
-class Callback$i {
- public:
-  // Default copy operations are appropriate for this class.
-  Callback$i() {}
-  template <class T> Callback$i(const T& functor)
-      : helper_(new RefCountedObject< HelperImpl<T> >(functor)) {}
-  R operator()($for j , [[P$j p$j]]) {
-    if (empty())
-      return R();
-    return helper_->Run($for j , [[p$j]]);
-  }
-  bool empty() const { return !helper_; }
-
- private:
-  struct Helper : RefCountInterface {
-    virtual ~Helper() {}
-    virtual R Run($for j , [[P$j p$j]]) = 0;
-  };
-  template <class T> struct HelperImpl : Helper {
-    explicit HelperImpl(const T& functor) : functor_(functor) {}
-    virtual R Run($for j , [[P$j p$j]]) {
-      return functor_($for j , [[p$j]]);
-    }
-    T functor_;
-  };
-  scoped_refptr<Helper> helper_;
-};
-
-]]
-}  // namespace rtc
-
-#endif  // WEBRTC_BASE_CALLBACK_H_