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Diffstat (limited to 'dom/media/webrtc/transport/sigslot.h')
| -rw-r--r-- | dom/media/webrtc/transport/sigslot.h | 619 |
1 files changed, 619 insertions, 0 deletions
diff --git a/dom/media/webrtc/transport/sigslot.h b/dom/media/webrtc/transport/sigslot.h new file mode 100644 index 0000000000..448e8137fe --- /dev/null +++ b/dom/media/webrtc/transport/sigslot.h @@ -0,0 +1,619 @@ +// sigslot.h: Signal/Slot classes +// +// Written by Sarah Thompson (sarah@telergy.com) 2002. +// +// License: Public domain. You are free to use this code however you like, with +// the proviso that the author takes on no responsibility or liability for any +// use. +// +// QUICK DOCUMENTATION +// +// (see also the full documentation at http://sigslot.sourceforge.net/) +// +// #define switches +// SIGSLOT_PURE_ISO: +// Define this to force ISO C++ compliance. This also disables all of +// the thread safety support on platforms where it is available. +// +// SIGSLOT_USE_POSIX_THREADS: +// Force use of Posix threads when using a C++ compiler other than gcc +// on a platform that supports Posix threads. (When using gcc, this is +// the default - use SIGSLOT_PURE_ISO to disable this if necessary) +// +// SIGSLOT_DEFAULT_MT_POLICY: +// Where thread support is enabled, this defaults to +// multi_threaded_global. Otherwise, the default is single_threaded. +// #define this yourself to override the default. In pure ISO mode, +// anything other than single_threaded will cause a compiler error. +// +// PLATFORM NOTES +// +// Win32: +// On Win32, the WEBRTC_WIN symbol must be #defined. Most mainstream +// compilers do this by default, but you may need to define it yourself +// if your build environment is less standard. This causes the Win32 +// thread support to be compiled in and used automatically. +// +// Unix/Linux/BSD, etc.: +// If you're using gcc, it is assumed that you have Posix threads +// available, so they are used automatically. You can override this (as +// under Windows) with the SIGSLOT_PURE_ISO switch. If you're using +// something other than gcc but still want to use Posix threads, you +// need to #define SIGSLOT_USE_POSIX_THREADS. +// +// ISO C++: +// If none of the supported platforms are detected, or if +// SIGSLOT_PURE_ISO is defined, all multithreading support is turned +// off, along with any code that might cause a pure ISO C++ environment +// to complain. Before you ask, gcc -ansi -pedantic won't compile this +// library, but gcc -ansi is fine. Pedantic mode seems to throw a lot of +// errors that aren't really there. If you feel like investigating this, +// please contact the author. +// +// +// THREADING MODES +// +// single_threaded: +// Your program is assumed to be single threaded from the point of view +// of signal/slot usage (i.e. all objects using signals and slots are +// created and destroyed from a single thread). Behaviour if objects are +// destroyed concurrently is undefined (i.e. you'll get the occasional +// segmentation fault/memory exception). +// +// multi_threaded_global: +// Your program is assumed to be multi threaded. Objects using signals +// and slots can be safely created and destroyed from any thread, even +// when connections exist. In multi_threaded_global mode, this is +// achieved by a single global mutex (actually a critical section on +// Windows because they are faster). This option uses less OS resources, +// but results in more opportunities for contention, possibly resulting +// in more context switches than are strictly necessary. +// +// multi_threaded_local: +// Behaviour in this mode is essentially the same as +// multi_threaded_global, except that each signal, and each object that +// inherits has_slots, all have their own mutex/critical section. In +// practice, this means that mutex collisions (and hence context +// switches) only happen if they are absolutely essential. However, on +// some platforms, creating a lot of mutexes can slow down the whole OS, +// so use this option with care. +// +// USING THE LIBRARY +// +// See the full documentation at http://sigslot.sourceforge.net/ +// +// Libjingle specific: +// +// This file has been modified such that has_slots and signalx do not have to be +// using the same threading requirements. E.g. it is possible to connect a +// has_slots<single_threaded> and signal0<multi_threaded_local> or +// has_slots<multi_threaded_local> and signal0<single_threaded>. +// If has_slots is single threaded the user must ensure that it is not trying +// to connect or disconnect to signalx concurrently or data race may occur. +// If signalx is single threaded the user must ensure that disconnect, connect +// or signal is not happening concurrently or data race may occur. + +#ifndef RTC_BASE_SIGSLOT_H_ +#define RTC_BASE_SIGSLOT_H_ + +#include <stdlib.h> +#include <cstring> +#include <list> +#include <set> + +// On our copy of sigslot.h, we set single threading as default. +#define SIGSLOT_DEFAULT_MT_POLICY single_threaded + +#if defined(SIGSLOT_PURE_ISO) || \ + (!defined(WEBRTC_WIN) && !defined(__GNUG__) && \ + !defined(SIGSLOT_USE_POSIX_THREADS)) +# define _SIGSLOT_SINGLE_THREADED +#elif defined(WEBRTC_WIN) +# define _SIGSLOT_HAS_WIN32_THREADS +# if !defined(WIN32_LEAN_AND_MEAN) +# define WIN32_LEAN_AND_MEAN +# endif +# include "rtc_base/win32.h" +#elif defined(__GNUG__) || defined(SIGSLOT_USE_POSIX_THREADS) +# define _SIGSLOT_HAS_POSIX_THREADS +# include <pthread.h> +#else +# define _SIGSLOT_SINGLE_THREADED +#endif + +#ifndef SIGSLOT_DEFAULT_MT_POLICY +# ifdef _SIGSLOT_SINGLE_THREADED +# define SIGSLOT_DEFAULT_MT_POLICY single_threaded +# else +# define SIGSLOT_DEFAULT_MT_POLICY multi_threaded_local +# endif +#endif + +// TODO: change this namespace to rtc? +namespace sigslot { + +class single_threaded { + public: + void lock() {} + void unlock() {} +}; + +#ifdef _SIGSLOT_HAS_WIN32_THREADS +// The multi threading policies only get compiled in if they are enabled. +class multi_threaded_global { + public: + multi_threaded_global() { + static bool isinitialised = false; + + if (!isinitialised) { + InitializeCriticalSection(get_critsec()); + isinitialised = true; + } + } + + void lock() { EnterCriticalSection(get_critsec()); } + + void unlock() { LeaveCriticalSection(get_critsec()); } + + private: + CRITICAL_SECTION* get_critsec() { + static CRITICAL_SECTION g_critsec; + return &g_critsec; + } +}; + +class multi_threaded_local { + public: + multi_threaded_local() { InitializeCriticalSection(&m_critsec); } + + multi_threaded_local(const multi_threaded_local&) { + InitializeCriticalSection(&m_critsec); + } + + ~multi_threaded_local() { DeleteCriticalSection(&m_critsec); } + + void lock() { EnterCriticalSection(&m_critsec); } + + void unlock() { LeaveCriticalSection(&m_critsec); } + + private: + CRITICAL_SECTION m_critsec; +}; +#endif // _SIGSLOT_HAS_WIN32_THREADS + +#ifdef _SIGSLOT_HAS_POSIX_THREADS +// The multi threading policies only get compiled in if they are enabled. +class multi_threaded_global { + public: + void lock() { pthread_mutex_lock(get_mutex()); } + void unlock() { pthread_mutex_unlock(get_mutex()); } + + private: + static pthread_mutex_t* get_mutex(); +}; + +class multi_threaded_local { + public: + multi_threaded_local() { pthread_mutex_init(&m_mutex, nullptr); } + multi_threaded_local(const multi_threaded_local&) { + pthread_mutex_init(&m_mutex, nullptr); + } + ~multi_threaded_local() { pthread_mutex_destroy(&m_mutex); } + void lock() { pthread_mutex_lock(&m_mutex); } + void unlock() { pthread_mutex_unlock(&m_mutex); } + + private: + pthread_mutex_t m_mutex; +}; +#endif // _SIGSLOT_HAS_POSIX_THREADS + +template <class mt_policy> +class lock_block { + public: + mt_policy* m_mutex; + + explicit lock_block(mt_policy* mtx) : m_mutex(mtx) { m_mutex->lock(); } + + ~lock_block() { m_mutex->unlock(); } +}; + +class _signal_base_interface; + +class has_slots_interface { + private: + typedef void (*signal_connect_t)(has_slots_interface* self, + _signal_base_interface* sender); + typedef void (*signal_disconnect_t)(has_slots_interface* self, + _signal_base_interface* sender); + typedef void (*disconnect_all_t)(has_slots_interface* self); + + const signal_connect_t m_signal_connect; + const signal_disconnect_t m_signal_disconnect; + const disconnect_all_t m_disconnect_all; + + protected: + has_slots_interface(signal_connect_t conn, signal_disconnect_t disc, + disconnect_all_t disc_all) + : m_signal_connect(conn), + m_signal_disconnect(disc), + m_disconnect_all(disc_all) {} + + // Doesn't really need to be virtual, but is for backwards compatibility + // (it was virtual in a previous version of sigslot). + virtual ~has_slots_interface() = default; + + public: + void signal_connect(_signal_base_interface* sender) { + m_signal_connect(this, sender); + } + + void signal_disconnect(_signal_base_interface* sender) { + m_signal_disconnect(this, sender); + } + + void disconnect_all() { m_disconnect_all(this); } +}; + +class _signal_base_interface { + private: + typedef void (*slot_disconnect_t)(_signal_base_interface* self, + has_slots_interface* pslot); + typedef void (*slot_duplicate_t)(_signal_base_interface* self, + const has_slots_interface* poldslot, + has_slots_interface* pnewslot); + + const slot_disconnect_t m_slot_disconnect; + const slot_duplicate_t m_slot_duplicate; + + protected: + _signal_base_interface(slot_disconnect_t disc, slot_duplicate_t dupl) + : m_slot_disconnect(disc), m_slot_duplicate(dupl) {} + + ~_signal_base_interface() = default; + + public: + void slot_disconnect(has_slots_interface* pslot) { + m_slot_disconnect(this, pslot); + } + + void slot_duplicate(const has_slots_interface* poldslot, + has_slots_interface* pnewslot) { + m_slot_duplicate(this, poldslot, pnewslot); + } +}; + +class _opaque_connection { + private: + typedef void (*emit_t)(const _opaque_connection*); + template <typename FromT, typename ToT> + union union_caster { + FromT from; + ToT to; + }; + + emit_t pemit; + has_slots_interface* pdest; + // Pointers to member functions may be up to 16 bytes for virtual classes, + // so make sure we have enough space to store it. + unsigned char pmethod[16]; + + public: + template <typename DestT, typename... Args> + _opaque_connection(DestT* pd, void (DestT::*pm)(Args...)) : pdest(pd) { + typedef void (DestT::*pm_t)(Args...); + static_assert(sizeof(pm_t) <= sizeof(pmethod), + "Size of slot function pointer too large."); + + std::memcpy(pmethod, &pm, sizeof(pm_t)); + + typedef void (*em_t)(const _opaque_connection* self, Args...); + union_caster<em_t, emit_t> caster2; + caster2.from = &_opaque_connection::emitter<DestT, Args...>; + pemit = caster2.to; + } + + has_slots_interface* getdest() const { return pdest; } + + _opaque_connection duplicate(has_slots_interface* newtarget) const { + _opaque_connection res = *this; + res.pdest = newtarget; + return res; + } + + // Just calls the stored "emitter" function pointer stored at construction + // time. + template <typename... Args> + void emit(Args... args) const { + typedef void (*em_t)(const _opaque_connection*, Args...); + union_caster<emit_t, em_t> caster; + caster.from = pemit; + (caster.to)(this, args...); + } + + private: + template <typename DestT, typename... Args> + static void emitter(const _opaque_connection* self, Args... args) { + typedef void (DestT::*pm_t)(Args...); + pm_t pm; + std::memcpy(&pm, self->pmethod, sizeof(pm_t)); + (static_cast<DestT*>(self->pdest)->*(pm))(args...); + } +}; + +template <class mt_policy> +class _signal_base : public _signal_base_interface, public mt_policy { + protected: + typedef std::list<_opaque_connection> connections_list; + + _signal_base() + : _signal_base_interface(&_signal_base::do_slot_disconnect, + &_signal_base::do_slot_duplicate), + m_current_iterator(m_connected_slots.end()) {} + + ~_signal_base() { disconnect_all(); } + + private: + _signal_base& operator=(_signal_base const& that); + + public: + _signal_base(const _signal_base& o) + : _signal_base_interface(&_signal_base::do_slot_disconnect, + &_signal_base::do_slot_duplicate), + m_current_iterator(m_connected_slots.end()) { + lock_block<mt_policy> lock(this); + for (const auto& connection : o.m_connected_slots) { + connection.getdest()->signal_connect(this); + m_connected_slots.push_back(connection); + } + } + + bool is_empty() { + lock_block<mt_policy> lock(this); + return m_connected_slots.empty(); + } + + void disconnect_all() { + lock_block<mt_policy> lock(this); + + while (!m_connected_slots.empty()) { + has_slots_interface* pdest = m_connected_slots.front().getdest(); + m_connected_slots.pop_front(); + pdest->signal_disconnect(static_cast<_signal_base_interface*>(this)); + } + // If disconnect_all is called while the signal is firing, advance the + // current slot iterator to the end to avoid an invalidated iterator from + // being dereferenced. + m_current_iterator = m_connected_slots.end(); + } + +#if !defined(NDEBUG) + bool connected(has_slots_interface* pclass) { + lock_block<mt_policy> lock(this); + connections_list::const_iterator it = m_connected_slots.begin(); + connections_list::const_iterator itEnd = m_connected_slots.end(); + while (it != itEnd) { + if (it->getdest() == pclass) return true; + ++it; + } + return false; + } +#endif + + void disconnect(has_slots_interface* pclass) { + lock_block<mt_policy> lock(this); + connections_list::iterator it = m_connected_slots.begin(); + connections_list::iterator itEnd = m_connected_slots.end(); + + while (it != itEnd) { + if (it->getdest() == pclass) { + // If we're currently using this iterator because the signal is firing, + // advance it to avoid it being invalidated. + if (m_current_iterator == it) { + m_current_iterator = m_connected_slots.erase(it); + } else { + m_connected_slots.erase(it); + } + pclass->signal_disconnect(static_cast<_signal_base_interface*>(this)); + return; + } + ++it; + } + } + + private: + static void do_slot_disconnect(_signal_base_interface* p, + has_slots_interface* pslot) { + _signal_base* const self = static_cast<_signal_base*>(p); + lock_block<mt_policy> lock(self); + connections_list::iterator it = self->m_connected_slots.begin(); + connections_list::iterator itEnd = self->m_connected_slots.end(); + + while (it != itEnd) { + connections_list::iterator itNext = it; + ++itNext; + + if (it->getdest() == pslot) { + // If we're currently using this iterator because the signal is firing, + // advance it to avoid it being invalidated. + if (self->m_current_iterator == it) { + self->m_current_iterator = self->m_connected_slots.erase(it); + } else { + self->m_connected_slots.erase(it); + } + } + + it = itNext; + } + } + + static void do_slot_duplicate(_signal_base_interface* p, + const has_slots_interface* oldtarget, + has_slots_interface* newtarget) { + _signal_base* const self = static_cast<_signal_base*>(p); + lock_block<mt_policy> lock(self); + connections_list::iterator it = self->m_connected_slots.begin(); + connections_list::iterator itEnd = self->m_connected_slots.end(); + + while (it != itEnd) { + if (it->getdest() == oldtarget) { + self->m_connected_slots.push_back(it->duplicate(newtarget)); + } + + ++it; + } + } + + protected: + connections_list m_connected_slots; + + // Used to handle a slot being disconnected while a signal is + // firing (iterating m_connected_slots). + connections_list::iterator m_current_iterator; + bool m_erase_current_iterator = false; +}; + +template <class mt_policy = SIGSLOT_DEFAULT_MT_POLICY> +class has_slots : public has_slots_interface, public mt_policy { + private: + typedef std::set<_signal_base_interface*> sender_set; + typedef sender_set::const_iterator const_iterator; + + public: + has_slots() + : has_slots_interface(&has_slots::do_signal_connect, + &has_slots::do_signal_disconnect, + &has_slots::do_disconnect_all) {} + + has_slots(has_slots const& o) + : has_slots_interface(&has_slots::do_signal_connect, + &has_slots::do_signal_disconnect, + &has_slots::do_disconnect_all) { + lock_block<mt_policy> lock(this); + for (auto* sender : o.m_senders) { + sender->slot_duplicate(&o, this); + m_senders.insert(sender); + } + } + + ~has_slots() { this->disconnect_all(); } + + private: + has_slots& operator=(has_slots const&); + + static void do_signal_connect(has_slots_interface* p, + _signal_base_interface* sender) { + has_slots* const self = static_cast<has_slots*>(p); + lock_block<mt_policy> lock(self); + self->m_senders.insert(sender); + } + + static void do_signal_disconnect(has_slots_interface* p, + _signal_base_interface* sender) { + has_slots* const self = static_cast<has_slots*>(p); + lock_block<mt_policy> lock(self); + self->m_senders.erase(sender); + } + + static void do_disconnect_all(has_slots_interface* p) { + has_slots* const self = static_cast<has_slots*>(p); + lock_block<mt_policy> lock(self); + while (!self->m_senders.empty()) { + std::set<_signal_base_interface*> senders; + senders.swap(self->m_senders); + const_iterator it = senders.begin(); + const_iterator itEnd = senders.end(); + + while (it != itEnd) { + _signal_base_interface* s = *it; + ++it; + s->slot_disconnect(p); + } + } + } + + private: + sender_set m_senders; +}; + +template <class mt_policy, typename... Args> +class signal_with_thread_policy : public _signal_base<mt_policy> { + private: + typedef _signal_base<mt_policy> base; + + protected: + typedef typename base::connections_list connections_list; + + public: + signal_with_thread_policy() = default; + + template <class desttype> + void connect(desttype* pclass, void (desttype::*pmemfun)(Args...)) { + lock_block<mt_policy> lock(this); + this->m_connected_slots.push_back(_opaque_connection(pclass, pmemfun)); + pclass->signal_connect(static_cast<_signal_base_interface*>(this)); + } + + void emit(Args... args) { + lock_block<mt_policy> lock(this); + this->m_current_iterator = this->m_connected_slots.begin(); + while (this->m_current_iterator != this->m_connected_slots.end()) { + _opaque_connection const& conn = *this->m_current_iterator; + ++(this->m_current_iterator); + conn.emit<Args...>(args...); + } + } + + void operator()(Args... args) { emit(args...); } +}; + +// Alias with default thread policy. Needed because both default arguments +// and variadic template arguments must go at the end of the list, so we +// can't have both at once. +template <typename... Args> +using signal = signal_with_thread_policy<SIGSLOT_DEFAULT_MT_POLICY, Args...>; + +// The previous verion of sigslot didn't use variadic templates, so you would +// need to write "sigslot::signal2<Arg1, Arg2>", for example. +// Now you can just write "sigslot::signal<Arg1, Arg2>", but these aliases +// exist for backwards compatibility. +template <typename mt_policy = SIGSLOT_DEFAULT_MT_POLICY> +using signal0 = signal_with_thread_policy<mt_policy>; + +template <typename A1, typename mt_policy = SIGSLOT_DEFAULT_MT_POLICY> +using signal1 = signal_with_thread_policy<mt_policy, A1>; + +template <typename A1, typename A2, + typename mt_policy = SIGSLOT_DEFAULT_MT_POLICY> +using signal2 = signal_with_thread_policy<mt_policy, A1, A2>; + +template <typename A1, typename A2, typename A3, + typename mt_policy = SIGSLOT_DEFAULT_MT_POLICY> +using signal3 = signal_with_thread_policy<mt_policy, A1, A2, A3>; + +template <typename A1, typename A2, typename A3, typename A4, + typename mt_policy = SIGSLOT_DEFAULT_MT_POLICY> +using signal4 = signal_with_thread_policy<mt_policy, A1, A2, A3, A4>; + +template <typename A1, typename A2, typename A3, typename A4, typename A5, + typename mt_policy = SIGSLOT_DEFAULT_MT_POLICY> +using signal5 = signal_with_thread_policy<mt_policy, A1, A2, A3, A4, A5>; + +template <typename A1, typename A2, typename A3, typename A4, typename A5, + typename A6, typename mt_policy = SIGSLOT_DEFAULT_MT_POLICY> +using signal6 = signal_with_thread_policy<mt_policy, A1, A2, A3, A4, A5, A6>; + +template <typename A1, typename A2, typename A3, typename A4, typename A5, + typename A6, typename A7, + typename mt_policy = SIGSLOT_DEFAULT_MT_POLICY> +using signal7 = + signal_with_thread_policy<mt_policy, A1, A2, A3, A4, A5, A6, A7>; + +template <typename A1, typename A2, typename A3, typename A4, typename A5, + typename A6, typename A7, typename A8, + typename mt_policy = SIGSLOT_DEFAULT_MT_POLICY> +using signal8 = + signal_with_thread_policy<mt_policy, A1, A2, A3, A4, A5, A6, A7, A8>; + +} // namespace sigslot + +#endif // RTC_BASE_SIGSLOT_H_ |