424 lines
17 KiB
C++
424 lines
17 KiB
C++
/*
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* Copyright 2013 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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// This file contains Macros for creating proxies for webrtc MediaStream and
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// PeerConnection classes.
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// TODO(deadbeef): Move this to pc/; this is part of the implementation.
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// The proxied objects are initialized with either one or two thread
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// objects that operations can be proxied to: The primary and secondary
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// threads.
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// In common usage, the primary thread will be the PeerConnection's
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// signaling thread, and the secondary thread will be either the
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// PeerConnection's worker thread or the PeerConnection's network thread.
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//
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// Example usage:
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//
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// class TestInterface : public rtc::RefCountInterface {
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// public:
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// std::string FooA() = 0;
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// std::string FooB(bool arg1) const = 0;
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// std::string FooC(bool arg1) = 0;
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// };
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//
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// Note that return types can not be a const reference.
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//
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// class Test : public TestInterface {
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// ... implementation of the interface.
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// };
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//
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// BEGIN_PROXY_MAP(Test)
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// PROXY_PRIMARY_THREAD_DESTRUCTOR()
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// PROXY_METHOD0(std::string, FooA)
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// PROXY_CONSTMETHOD1(std::string, FooB, arg1)
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// PROXY_SECONDARY_METHOD1(std::string, FooC, arg1)
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// END_PROXY_MAP()
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//
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// Where the destructor and first two methods are invoked on the primary
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// thread, and the third is invoked on the secondary thread.
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//
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// The proxy can be created using
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//
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// TestProxy::Create(Thread* signaling_thread, Thread* worker_thread,
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// TestInterface*).
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//
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// The variant defined with BEGIN_PRIMARY_PROXY_MAP is unaware of
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// the secondary thread, and invokes all methods on the primary thread.
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//
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// The variant defined with BEGIN_OWNED_PROXY_MAP does not use
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// refcounting, and instead just takes ownership of the object being proxied.
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#ifndef API_PROXY_H_
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#define API_PROXY_H_
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#include <memory>
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#include <string>
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#include <tuple>
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#include <type_traits>
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#include <utility>
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#include "api/scoped_refptr.h"
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#include "api/task_queue/queued_task.h"
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#include "api/task_queue/task_queue_base.h"
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#include "rtc_base/event.h"
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#include "rtc_base/message_handler.h"
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#include "rtc_base/ref_counted_object.h"
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#include "rtc_base/system/rtc_export.h"
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#include "rtc_base/thread.h"
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namespace rtc {
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class Location;
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}
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namespace webrtc {
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template <typename R>
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class ReturnType {
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public:
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template <typename C, typename M, typename... Args>
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void Invoke(C* c, M m, Args&&... args) {
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r_ = (c->*m)(std::forward<Args>(args)...);
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}
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R moved_result() { return std::move(r_); }
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private:
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R r_;
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};
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template <>
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class ReturnType<void> {
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public:
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template <typename C, typename M, typename... Args>
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void Invoke(C* c, M m, Args&&... args) {
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(c->*m)(std::forward<Args>(args)...);
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}
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void moved_result() {}
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};
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template <typename C, typename R, typename... Args>
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class MethodCall : public QueuedTask {
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public:
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typedef R (C::*Method)(Args...);
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MethodCall(C* c, Method m, Args&&... args)
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: c_(c),
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m_(m),
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args_(std::forward_as_tuple(std::forward<Args>(args)...)) {}
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R Marshal(const rtc::Location& posted_from, rtc::Thread* t) {
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if (t->IsCurrent()) {
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Invoke(std::index_sequence_for<Args...>());
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} else {
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t->PostTask(std::unique_ptr<QueuedTask>(this));
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event_.Wait(rtc::Event::kForever);
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}
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return r_.moved_result();
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}
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private:
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bool Run() override {
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Invoke(std::index_sequence_for<Args...>());
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event_.Set();
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return false;
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}
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template <size_t... Is>
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void Invoke(std::index_sequence<Is...>) {
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r_.Invoke(c_, m_, std::move(std::get<Is>(args_))...);
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}
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C* c_;
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Method m_;
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ReturnType<R> r_;
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std::tuple<Args&&...> args_;
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rtc::Event event_;
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};
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template <typename C, typename R, typename... Args>
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class ConstMethodCall : public QueuedTask {
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public:
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typedef R (C::*Method)(Args...) const;
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ConstMethodCall(const C* c, Method m, Args&&... args)
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: c_(c),
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m_(m),
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args_(std::forward_as_tuple(std::forward<Args>(args)...)) {}
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R Marshal(const rtc::Location& posted_from, rtc::Thread* t) {
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if (t->IsCurrent()) {
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Invoke(std::index_sequence_for<Args...>());
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} else {
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t->PostTask(std::unique_ptr<QueuedTask>(this));
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event_.Wait(rtc::Event::kForever);
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}
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return r_.moved_result();
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}
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private:
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bool Run() override {
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Invoke(std::index_sequence_for<Args...>());
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event_.Set();
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return false;
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}
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template <size_t... Is>
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void Invoke(std::index_sequence<Is...>) {
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r_.Invoke(c_, m_, std::move(std::get<Is>(args_))...);
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}
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const C* c_;
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Method m_;
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ReturnType<R> r_;
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std::tuple<Args&&...> args_;
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rtc::Event event_;
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};
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// Helper macros to reduce code duplication.
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#define PROXY_MAP_BOILERPLATE(c) \
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template <class INTERNAL_CLASS> \
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class c##ProxyWithInternal; \
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typedef c##ProxyWithInternal<c##Interface> c##Proxy; \
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template <class INTERNAL_CLASS> \
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class c##ProxyWithInternal : public c##Interface { \
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protected: \
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typedef c##Interface C; \
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\
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public: \
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const INTERNAL_CLASS* internal() const { return c_; } \
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INTERNAL_CLASS* internal() { return c_; }
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// clang-format off
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// clang-format would put the semicolon alone,
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// leading to a presubmit error (cpplint.py)
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#define END_PROXY_MAP() \
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};
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// clang-format on
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#define PRIMARY_PROXY_MAP_BOILERPLATE(c) \
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protected: \
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c##ProxyWithInternal(rtc::Thread* primary_thread, INTERNAL_CLASS* c) \
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: primary_thread_(primary_thread), c_(c) {} \
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\
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private: \
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mutable rtc::Thread* primary_thread_;
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#define SECONDARY_PROXY_MAP_BOILERPLATE(c) \
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protected: \
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c##ProxyWithInternal(rtc::Thread* primary_thread, \
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rtc::Thread* secondary_thread, INTERNAL_CLASS* c) \
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: primary_thread_(primary_thread), \
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secondary_thread_(secondary_thread), \
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c_(c) {} \
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\
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private: \
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mutable rtc::Thread* primary_thread_; \
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mutable rtc::Thread* secondary_thread_;
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// Note that the destructor is protected so that the proxy can only be
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// destroyed via RefCountInterface.
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#define REFCOUNTED_PROXY_MAP_BOILERPLATE(c) \
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protected: \
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~c##ProxyWithInternal() { \
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MethodCall<c##ProxyWithInternal, void> call( \
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this, &c##ProxyWithInternal::DestroyInternal); \
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call.Marshal(RTC_FROM_HERE, destructor_thread()); \
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} \
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\
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private: \
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void DestroyInternal() { c_ = nullptr; } \
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rtc::scoped_refptr<INTERNAL_CLASS> c_;
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// Note: This doesn't use a unique_ptr, because it intends to handle a corner
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// case where an object's deletion triggers a callback that calls back into
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// this proxy object. If relying on a unique_ptr to delete the object, its
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// inner pointer would be set to null before this reentrant callback would have
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// a chance to run, resulting in a segfault.
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#define OWNED_PROXY_MAP_BOILERPLATE(c) \
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public: \
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~c##ProxyWithInternal() { \
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MethodCall<c##ProxyWithInternal, void> call( \
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this, &c##ProxyWithInternal::DestroyInternal); \
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call.Marshal(RTC_FROM_HERE, destructor_thread()); \
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} \
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\
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private: \
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void DestroyInternal() { delete c_; } \
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INTERNAL_CLASS* c_;
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#define BEGIN_PRIMARY_PROXY_MAP(c) \
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PROXY_MAP_BOILERPLATE(c) \
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PRIMARY_PROXY_MAP_BOILERPLATE(c) \
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REFCOUNTED_PROXY_MAP_BOILERPLATE(c) \
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public: \
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static rtc::scoped_refptr<c##ProxyWithInternal> Create( \
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rtc::Thread* primary_thread, INTERNAL_CLASS* c) { \
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return new rtc::RefCountedObject<c##ProxyWithInternal>(primary_thread, c); \
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}
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#define BEGIN_PROXY_MAP(c) \
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PROXY_MAP_BOILERPLATE(c) \
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SECONDARY_PROXY_MAP_BOILERPLATE(c) \
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REFCOUNTED_PROXY_MAP_BOILERPLATE(c) \
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public: \
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static rtc::scoped_refptr<c##ProxyWithInternal> Create( \
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rtc::Thread* primary_thread, rtc::Thread* secondary_thread, \
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INTERNAL_CLASS* c) { \
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return new rtc::RefCountedObject<c##ProxyWithInternal>( \
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primary_thread, secondary_thread, c); \
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}
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#define BEGIN_OWNED_PROXY_MAP(c) \
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PROXY_MAP_BOILERPLATE(c) \
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SECONDARY_PROXY_MAP_BOILERPLATE(c) \
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OWNED_PROXY_MAP_BOILERPLATE(c) \
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public: \
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static std::unique_ptr<c##Interface> Create( \
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rtc::Thread* primary_thread, rtc::Thread* secondary_thread, \
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std::unique_ptr<INTERNAL_CLASS> c) { \
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return std::unique_ptr<c##Interface>(new c##ProxyWithInternal( \
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primary_thread, secondary_thread, c.release())); \
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}
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#define PROXY_PRIMARY_THREAD_DESTRUCTOR() \
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private: \
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rtc::Thread* destructor_thread() const { return primary_thread_; } \
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\
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public: // NOLINTNEXTLINE
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#define PROXY_SECONDARY_THREAD_DESTRUCTOR() \
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private: \
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rtc::Thread* destructor_thread() const { return secondary_thread_; } \
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\
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public: // NOLINTNEXTLINE
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#define PROXY_METHOD0(r, method) \
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r method() override { \
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MethodCall<C, r> call(c_, &C::method); \
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return call.Marshal(RTC_FROM_HERE, primary_thread_); \
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}
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#define PROXY_CONSTMETHOD0(r, method) \
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r method() const override { \
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ConstMethodCall<C, r> call(c_, &C::method); \
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return call.Marshal(RTC_FROM_HERE, primary_thread_); \
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}
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#define PROXY_METHOD1(r, method, t1) \
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r method(t1 a1) override { \
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MethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
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return call.Marshal(RTC_FROM_HERE, primary_thread_); \
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}
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#define PROXY_CONSTMETHOD1(r, method, t1) \
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r method(t1 a1) const override { \
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ConstMethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
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return call.Marshal(RTC_FROM_HERE, primary_thread_); \
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}
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#define PROXY_METHOD2(r, method, t1, t2) \
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r method(t1 a1, t2 a2) override { \
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MethodCall<C, r, t1, t2> call(c_, &C::method, std::move(a1), \
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std::move(a2)); \
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return call.Marshal(RTC_FROM_HERE, primary_thread_); \
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}
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#define PROXY_METHOD3(r, method, t1, t2, t3) \
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r method(t1 a1, t2 a2, t3 a3) override { \
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MethodCall<C, r, t1, t2, t3> call(c_, &C::method, std::move(a1), \
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std::move(a2), std::move(a3)); \
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return call.Marshal(RTC_FROM_HERE, primary_thread_); \
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}
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#define PROXY_METHOD4(r, method, t1, t2, t3, t4) \
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r method(t1 a1, t2 a2, t3 a3, t4 a4) override { \
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MethodCall<C, r, t1, t2, t3, t4> call(c_, &C::method, std::move(a1), \
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std::move(a2), std::move(a3), \
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std::move(a4)); \
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return call.Marshal(RTC_FROM_HERE, primary_thread_); \
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}
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#define PROXY_METHOD5(r, method, t1, t2, t3, t4, t5) \
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r method(t1 a1, t2 a2, t3 a3, t4 a4, t5 a5) override { \
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MethodCall<C, r, t1, t2, t3, t4, t5> call(c_, &C::method, std::move(a1), \
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std::move(a2), std::move(a3), \
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std::move(a4), std::move(a5)); \
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return call.Marshal(RTC_FROM_HERE, primary_thread_); \
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}
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// Define methods which should be invoked on the secondary thread.
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#define PROXY_SECONDARY_METHOD0(r, method) \
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r method() override { \
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MethodCall<C, r> call(c_, &C::method); \
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return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
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}
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#define PROXY_SECONDARY_CONSTMETHOD0(r, method) \
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r method() const override { \
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ConstMethodCall<C, r> call(c_, &C::method); \
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return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
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}
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#define PROXY_SECONDARY_METHOD1(r, method, t1) \
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r method(t1 a1) override { \
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MethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
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return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
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}
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#define PROXY_SECONDARY_CONSTMETHOD1(r, method, t1) \
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r method(t1 a1) const override { \
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ConstMethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
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return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
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}
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#define PROXY_SECONDARY_METHOD2(r, method, t1, t2) \
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r method(t1 a1, t2 a2) override { \
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MethodCall<C, r, t1, t2> call(c_, &C::method, std::move(a1), \
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std::move(a2)); \
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return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
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}
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#define PROXY_SECONDARY_CONSTMETHOD2(r, method, t1, t2) \
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r method(t1 a1, t2 a2) const override { \
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ConstMethodCall<C, r, t1, t2> call(c_, &C::method, std::move(a1), \
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std::move(a2)); \
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return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
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}
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#define PROXY_SECONDARY_METHOD3(r, method, t1, t2, t3) \
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r method(t1 a1, t2 a2, t3 a3) override { \
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MethodCall<C, r, t1, t2, t3> call(c_, &C::method, std::move(a1), \
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std::move(a2), std::move(a3)); \
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return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
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}
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#define PROXY_SECONDARY_CONSTMETHOD3(r, method, t1, t2) \
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r method(t1 a1, t2 a2, t3 a3) const override { \
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ConstMethodCall<C, r, t1, t2, t3> call(c_, &C::method, std::move(a1), \
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std::move(a2), std::move(a3)); \
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return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
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}
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// For use when returning purely const state (set during construction).
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// Use with caution. This method should only be used when the return value will
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// always be the same.
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#define BYPASS_PROXY_CONSTMETHOD0(r, method) \
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r method() const override { \
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static_assert( \
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std::is_same<r, rtc::Thread*>::value || !std::is_pointer<r>::value, \
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"Type is a pointer"); \
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static_assert(!std::is_reference<r>::value, "Type is a reference"); \
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return c_->method(); \
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}
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} // namespace webrtc
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#endif // API_PROXY_H_
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