mirror of
https://github.com/mollyim/webrtc.git
synced 2025-05-16 15:20:42 +01:00
84255bbe3b
This is in preparation for deleting the include in rtc_base/refcount.h,
but that change has to wait for some downstream applications to
not rely in the indirect include.
Partial reland of "Make rtc_base/refcount.h self contained, not including refcountedobject.h."
This is a reland of b7239a9dc8
Original change's description:
> Make rtc_base/refcount.h self contained, not including refcountedobject.h.
>
> The refcount.h file doesn't depend on anything from
> refcountedobject.h. The motivation of this change to make it possible
> to add additional declarations to refcount.h, and include it from
> refcountedobject.h.
>
> Bug: webrtc:8270
> Change-Id: I24f6131f471e675570968d00065ff9b1f55e3373
> Reviewed-on: https://webrtc-review.googlesource.com/5760
> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
> Commit-Queue: Niels Moller <nisse@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#20106}
Bug: webrtc:8270
Change-Id: I63a42712f6c1ec83823c629d1a954fd1a04d4a6c
Reviewed-on: https://webrtc-review.googlesource.com/7281
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20185}
104 lines
3.5 KiB
Text
104 lines
3.5 KiB
Text
/*
|
|
* 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:
|
|
// ../third_party/googletest/src/googletest/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 RTC_BASE_CALLBACK_H_
|
|
#define RTC_BASE_CALLBACK_H_
|
|
|
|
#include "rtc_base/refcount.h"
|
|
#include "rtc_base/refcountedobject.h"
|
|
#include "rtc_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 // RTC_BASE_CALLBACK_H_
|