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/*
* Copyright 2013 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.
*/
// This file contains Macros for creating proxies for webrtc MediaStream and
// PeerConnection classes.
// The proxied objects are initialized with either one or two thread
// objects that operations can be proxied to: The primary and secondary
// threads.
// In common usage, the primary thread will be the PeerConnection's
// signaling thread, and the secondary thread will be either the
// PeerConnection's worker thread or the PeerConnection's network thread.
//
// Example usage:
//
// class TestInterface : public RefCountInterface {
// public:
// std::string FooA() = 0;
// std::string FooB(bool arg1) const = 0;
// std::string FooC(bool arg1) = 0;
// };
//
// Note that return types can not be a const reference.
//
// class Test : public TestInterface {
// ... implementation of the interface.
// };
//
// BEGIN_PROXY_MAP(Test)
// PROXY_PRIMARY_THREAD_DESTRUCTOR()
// PROXY_METHOD0(std::string, FooA)
// PROXY_CONSTMETHOD1(std::string, FooB, arg1)
// PROXY_SECONDARY_METHOD1(std::string, FooC, arg1)
// END_PROXY_MAP()
//
// Where the destructor and first two methods are invoked on the primary
// thread, and the third is invoked on the secondary thread.
//
// The proxy can be created using
//
// TestProxy::Create(Thread* signaling_thread, Thread* worker_thread,
// TestInterface*).
//
// The variant defined with BEGIN_PRIMARY_PROXY_MAP is unaware of
// the secondary thread, and invokes all methods on the primary thread.
//
#ifndef PC_PROXY_H_
#define PC_PROXY_H_
#include <stddef.h>
#include <memory>
#include <string>
#include <tuple>
#include <type_traits>
#include <utility>
#include "api/scoped_refptr.h"
#include "api/task_queue/task_queue_base.h"
#include "rtc_base/event.h"
#include "rtc_base/string_utils.h"
#include "rtc_base/system/rtc_export.h"
#include "rtc_base/thread.h"
#include "rtc_base/trace_event.h"
#if !defined(RTC_DISABLE_PROXY_TRACE_EVENTS) && !defined(WEBRTC_CHROMIUM_BUILD)
#define RTC_DISABLE_PROXY_TRACE_EVENTS
#endif
namespace webrtc {
template <typename R>
class ReturnType {
public:
template <typename C, typename M, typename... Args>
void Invoke(C* c, M m, Args&&... args) {
r_ = (c->*m)(std::forward<Args>(args)...);
}
R moved_result() { return std::move(r_); }
private:
R r_;
};
template <>
class ReturnType<void> {
public:
template <typename C, typename M, typename... Args>
void Invoke(C* c, M m, Args&&... args) {
(c->*m)(std::forward<Args>(args)...);
}
void moved_result() {}
};
template <typename C, typename R, typename... Args>
class MethodCall {
public:
typedef R (C::*Method)(Args...);
MethodCall(C* c, Method m, Args&&... args)
: c_(c),
m_(m),
args_(std::forward_as_tuple(std::forward<Args>(args)...)) {}
R Marshal(rtc::Thread* t) {
if (t->IsCurrent()) {
Invoke(std::index_sequence_for<Args...>());
} else {
t->PostTask([this] {
Invoke(std::index_sequence_for<Args...>());
event_.Set();
});
event_.Wait(rtc::Event::kForever);
}
return r_.moved_result();
}
private:
template <size_t... Is>
void Invoke(std::index_sequence<Is...>) {
r_.Invoke(c_, m_, std::move(std::get<Is>(args_))...);
}
C* c_;
Method m_;
ReturnType<R> r_;
std::tuple<Args&&...> args_;
rtc::Event event_;
};
template <typename C, typename R, typename... Args>
class ConstMethodCall {
public:
typedef R (C::*Method)(Args...) const;
ConstMethodCall(const C* c, Method m, Args&&... args)
: c_(c),
m_(m),
args_(std::forward_as_tuple(std::forward<Args>(args)...)) {}
R Marshal(rtc::Thread* t) {
if (t->IsCurrent()) {
Invoke(std::index_sequence_for<Args...>());
} else {
t->PostTask([this] {
Invoke(std::index_sequence_for<Args...>());
event_.Set();
});
event_.Wait(rtc::Event::kForever);
}
return r_.moved_result();
}
private:
template <size_t... Is>
void Invoke(std::index_sequence<Is...>) {
r_.Invoke(c_, m_, std::move(std::get<Is>(args_))...);
}
const C* c_;
Method m_;
ReturnType<R> r_;
std::tuple<Args&&...> args_;
rtc::Event event_;
};
#define PROXY_STRINGIZE_IMPL(x) #x
#define PROXY_STRINGIZE(x) PROXY_STRINGIZE_IMPL(x)
// Helper macros to reduce code duplication.
#define PROXY_MAP_BOILERPLATE(class_name) \
template <class INTERNAL_CLASS> \
class class_name##ProxyWithInternal; \
typedef class_name##ProxyWithInternal<class_name##Interface> \
class_name##Proxy; \
template <class INTERNAL_CLASS> \
class class_name##ProxyWithInternal : public class_name##Interface { \
protected: \
static constexpr char proxy_name_[] = #class_name "Proxy"; \
typedef class_name##Interface C; \
\
public: \
const INTERNAL_CLASS* internal() const { \
return c(); \
} \
INTERNAL_CLASS* internal() { \
return c(); \
}
// clang-format off
// clang-format would put the semicolon alone,
// leading to a presubmit error (cpplint.py)
#define END_PROXY_MAP(class_name) \
}; \
template <class INTERNAL_CLASS> \
constexpr char class_name##ProxyWithInternal<INTERNAL_CLASS>::proxy_name_[];
// clang-format on
#define PRIMARY_PROXY_MAP_BOILERPLATE(class_name) \
protected: \
class_name##ProxyWithInternal(rtc::Thread* primary_thread, \
rtc::scoped_refptr<INTERNAL_CLASS> c) \
: primary_thread_(primary_thread), c_(std::move(c)) {} \
\
private: \
mutable rtc::Thread* primary_thread_;
#define SECONDARY_PROXY_MAP_BOILERPLATE(class_name) \
protected: \
class_name##ProxyWithInternal(rtc::Thread* primary_thread, \
rtc::Thread* secondary_thread, \
rtc::scoped_refptr<INTERNAL_CLASS> c) \
: primary_thread_(primary_thread), \
secondary_thread_(secondary_thread), \
c_(std::move(c)) {} \
\
private: \
mutable rtc::Thread* primary_thread_; \
mutable rtc::Thread* secondary_thread_;
// Note that the destructor is protected so that the proxy can only be
// destroyed via RefCountInterface.
#define REFCOUNTED_PROXY_MAP_BOILERPLATE(class_name) \
protected: \
~class_name##ProxyWithInternal() { \
MethodCall<class_name##ProxyWithInternal, void> call( \
this, &class_name##ProxyWithInternal::DestroyInternal); \
call.Marshal(destructor_thread()); \
} \
\
private: \
const INTERNAL_CLASS* c() const { \
return c_.get(); \
} \
INTERNAL_CLASS* c() { \
return c_.get(); \
} \
void DestroyInternal() { \
c_ = nullptr; \
} \
rtc::scoped_refptr<INTERNAL_CLASS> c_;
// Note: This doesn't use a unique_ptr, because it intends to handle a corner
// case where an object's deletion triggers a callback that calls back into
// this proxy object. If relying on a unique_ptr to delete the object, its
// inner pointer would be set to null before this reentrant callback would have
// a chance to run, resulting in a segfault.
#define OWNED_PROXY_MAP_BOILERPLATE(class_name) \
public: \
~class_name##ProxyWithInternal() { \
MethodCall<class_name##ProxyWithInternal, void> call( \
this, &class_name##ProxyWithInternal::DestroyInternal); \
call.Marshal(destructor_thread()); \
} \
\
private: \
const INTERNAL_CLASS* c() const { \
return c_; \
} \
INTERNAL_CLASS* c() { \
return c_; \
} \
void DestroyInternal() { \
delete c_; \
} \
INTERNAL_CLASS* c_;
#define BEGIN_PRIMARY_PROXY_MAP(class_name) \
PROXY_MAP_BOILERPLATE(class_name) \
PRIMARY_PROXY_MAP_BOILERPLATE(class_name) \
REFCOUNTED_PROXY_MAP_BOILERPLATE(class_name) \
public: \
static rtc::scoped_refptr<class_name##ProxyWithInternal> Create( \
rtc::Thread* primary_thread, rtc::scoped_refptr<INTERNAL_CLASS> c) { \
return rtc::make_ref_counted<class_name##ProxyWithInternal>( \
primary_thread, std::move(c)); \
}
#define BEGIN_PROXY_MAP(class_name) \
PROXY_MAP_BOILERPLATE(class_name) \
SECONDARY_PROXY_MAP_BOILERPLATE(class_name) \
REFCOUNTED_PROXY_MAP_BOILERPLATE(class_name) \
public: \
static rtc::scoped_refptr<class_name##ProxyWithInternal> Create( \
rtc::Thread* primary_thread, rtc::Thread* secondary_thread, \
rtc::scoped_refptr<INTERNAL_CLASS> c) { \
return rtc::make_ref_counted<class_name##ProxyWithInternal>( \
primary_thread, secondary_thread, std::move(c)); \
}
#define PROXY_PRIMARY_THREAD_DESTRUCTOR() \
private: \
rtc::Thread* destructor_thread() const { \
return primary_thread_; \
} \
\
public: // NOLINTNEXTLINE
#define PROXY_SECONDARY_THREAD_DESTRUCTOR() \
private: \
rtc::Thread* destructor_thread() const { \
return secondary_thread_; \
} \
\
public: // NOLINTNEXTLINE
#if defined(RTC_DISABLE_PROXY_TRACE_EVENTS)
#define TRACE_BOILERPLATE(method) \
do { \
} while (0)
#else // if defined(RTC_DISABLE_PROXY_TRACE_EVENTS)
#define TRACE_BOILERPLATE(method) \
static constexpr auto class_and_method_name = \
rtc::MakeCompileTimeString(proxy_name_) \
.Concat(rtc::MakeCompileTimeString("::")) \
.Concat(rtc::MakeCompileTimeString(#method)); \
TRACE_EVENT0("webrtc", class_and_method_name.string)
#endif // if defined(RTC_DISABLE_PROXY_TRACE_EVENTS)
#define PROXY_METHOD0(r, method) \
r method() override { \
TRACE_BOILERPLATE(method); \
MethodCall<C, r> call(c(), &C::method); \
return call.Marshal(primary_thread_); \
}
#define PROXY_CONSTMETHOD0(r, method) \
r method() const override { \
TRACE_BOILERPLATE(method); \
ConstMethodCall<C, r> call(c(), &C::method); \
return call.Marshal(primary_thread_); \
}
#define PROXY_METHOD1(r, method, t1) \
r method(t1 a1) override { \
TRACE_BOILERPLATE(method); \
MethodCall<C, r, t1> call(c(), &C::method, std::move(a1)); \
return call.Marshal(primary_thread_); \
}
#define PROXY_CONSTMETHOD1(r, method, t1) \
r method(t1 a1) const override { \
TRACE_BOILERPLATE(method); \
ConstMethodCall<C, r, t1> call(c(), &C::method, std::move(a1)); \
return call.Marshal(primary_thread_); \
}
#define PROXY_METHOD2(r, method, t1, t2) \
r method(t1 a1, t2 a2) override { \
TRACE_BOILERPLATE(method); \
MethodCall<C, r, t1, t2> call(c(), &C::method, std::move(a1), \
std::move(a2)); \
return call.Marshal(primary_thread_); \
}
#define PROXY_METHOD3(r, method, t1, t2, t3) \
r method(t1 a1, t2 a2, t3 a3) override { \
TRACE_BOILERPLATE(method); \
MethodCall<C, r, t1, t2, t3> call(c(), &C::method, std::move(a1), \
std::move(a2), std::move(a3)); \
return call.Marshal(primary_thread_); \
}
#define PROXY_METHOD4(r, method, t1, t2, t3, t4) \
r method(t1 a1, t2 a2, t3 a3, t4 a4) override { \
TRACE_BOILERPLATE(method); \
MethodCall<C, r, t1, t2, t3, t4> call(c(), &C::method, std::move(a1), \
std::move(a2), std::move(a3), \
std::move(a4)); \
return call.Marshal(primary_thread_); \
}
#define PROXY_METHOD5(r, method, t1, t2, t3, t4, t5) \
r method(t1 a1, t2 a2, t3 a3, t4 a4, t5 a5) override { \
TRACE_BOILERPLATE(method); \
MethodCall<C, r, t1, t2, t3, t4, t5> call(c(), &C::method, std::move(a1), \
std::move(a2), std::move(a3), \
std::move(a4), std::move(a5)); \
return call.Marshal(primary_thread_); \
}
// Define methods which should be invoked on the secondary thread.
#define PROXY_SECONDARY_METHOD0(r, method) \
r method() override { \
TRACE_BOILERPLATE(method); \
MethodCall<C, r> call(c(), &C::method); \
return call.Marshal(secondary_thread_); \
}
#define PROXY_SECONDARY_CONSTMETHOD0(r, method) \
r method() const override { \
TRACE_BOILERPLATE(method); \
ConstMethodCall<C, r> call(c(), &C::method); \
return call.Marshal(secondary_thread_); \
}
#define PROXY_SECONDARY_METHOD1(r, method, t1) \
r method(t1 a1) override { \
TRACE_BOILERPLATE(method); \
MethodCall<C, r, t1> call(c(), &C::method, std::move(a1)); \
return call.Marshal(secondary_thread_); \
}
#define PROXY_SECONDARY_CONSTMETHOD1(r, method, t1) \
r method(t1 a1) const override { \
TRACE_BOILERPLATE(method); \
ConstMethodCall<C, r, t1> call(c(), &C::method, std::move(a1)); \
return call.Marshal(secondary_thread_); \
}
#define PROXY_SECONDARY_METHOD2(r, method, t1, t2) \
r method(t1 a1, t2 a2) override { \
TRACE_BOILERPLATE(method); \
MethodCall<C, r, t1, t2> call(c(), &C::method, std::move(a1), \
std::move(a2)); \
return call.Marshal(secondary_thread_); \
}
#define PROXY_SECONDARY_CONSTMETHOD2(r, method, t1, t2) \
r method(t1 a1, t2 a2) const override { \
TRACE_BOILERPLATE(method); \
ConstMethodCall<C, r, t1, t2> call(c(), &C::method, std::move(a1), \
std::move(a2)); \
return call.Marshal(secondary_thread_); \
}
#define PROXY_SECONDARY_METHOD3(r, method, t1, t2, t3) \
r method(t1 a1, t2 a2, t3 a3) override { \
TRACE_BOILERPLATE(method); \
MethodCall<C, r, t1, t2, t3> call(c(), &C::method, std::move(a1), \
std::move(a2), std::move(a3)); \
return call.Marshal(secondary_thread_); \
}
#define PROXY_SECONDARY_CONSTMETHOD3(r, method, t1, t2) \
r method(t1 a1, t2 a2, t3 a3) const override { \
TRACE_BOILERPLATE(method); \
ConstMethodCall<C, r, t1, t2, t3> call(c(), &C::method, std::move(a1), \
std::move(a2), std::move(a3)); \
return call.Marshal(secondary_thread_); \
}
// For use when returning purely const state (set during construction).
// Use with caution. This method should only be used when the return value will
// always be the same.
#define BYPASS_PROXY_CONSTMETHOD0(r, method) \
r method() const override { \
TRACE_BOILERPLATE(method); \
return c_->method(); \
}
// Allows a custom implementation of a method where the otherwise proxied
// implementation can do a more efficient, yet thread-safe, job than the proxy
// can do by default or when more flexibility is needed than can be provided
// by a proxy.
// Note that calls to these methods should be expected to be made from unknown
// threads.
#define BYPASS_PROXY_METHOD0(r, method) \
r method() override { \
TRACE_BOILERPLATE(method); \
return c_->method(); \
}
// The 1 argument version of `BYPASS_PROXY_METHOD0`.
#define BYPASS_PROXY_METHOD1(r, method, t1) \
r method(t1 a1) override { \
TRACE_BOILERPLATE(method); \
return c_->method(std::move(a1)); \
}
// The 2 argument version of `BYPASS_PROXY_METHOD0`.
#define BYPASS_PROXY_METHOD2(r, method, t1, t2) \
r method(t1 a1, t2 a2) override { \
TRACE_BOILERPLATE(method); \
return c_->method(std::move(a1), std::move(a2)); \
}
} // namespace webrtc
#endif // PC_PROXY_H_