Implement runtime debug print filtering
The runtime debug print filtering support dynamic debug print selection. Tis patch only implements basic core support for filtering. The commands to change the runtime filtering settings will be added in a following patch. But even with only this one can change filtering settings by editing memory using a debugger. It can even be automated by using gdb break point commands.develop
Pauli
parent
ae5a1fad84
commit
ee999ccbdf
@ -0,0 +1,186 @@
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/**
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Copyright © 2018 Pauli <suokkos@gmail.com>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any
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damages arising from the use of this software.
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Permission is granted to anyone to use this software for any
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purpose, including commercial applications, and to alter it and
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redistribute it freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must
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not claim that you wrote the original software. If you use this
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software in a product, an acknowledgment in the product
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documentation would be appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and
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must not be misrepresented as being the original software.
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3. This notice may not be removed or altered from any source
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distribution.
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*/
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#define _POSIX_C_SOURCE 200809L
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#include "Core.h"
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#include "Debug.h"
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#include "DebugManager.h"
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#include <chrono>
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#include <iomanip>
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#include <thread>
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#ifdef _MSC_VER
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static tm* localtime_r(const time_t* time, tm* result)
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{
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localtime_s(result, time);
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return result;
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}
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#endif
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namespace DFHack {
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DBG_DECLARE(core,debug);
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void DebugManager::registerCategory(DebugCategory& cat)
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{
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DEBUG(debug) << "register DebugCategory '" << cat.category()
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<< "' from '" << cat.plugin()
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<< "' allowed " << cat.allowed() << std::endl;
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std::lock_guard<std::mutex> guard(access_mutex_);
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push_back(&cat);
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categorySignal(CAT_ADD, cat);
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}
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void DebugManager::unregisterCategory(DebugCategory& cat)
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{
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DEBUG(debug) << "unregister DebugCategory '" << cat.category()
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<< "' from '" << cat.plugin()
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<< "' allowed " << cat.allowed() << std::endl;
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std::lock_guard<std::mutex> guard(access_mutex_);
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auto iter = std::find(begin(), end(), &cat);
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std::swap(*iter, back());
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pop_back();
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categorySignal(CAT_REMOVE, cat);
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}
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DebugRegisterBase::DebugRegisterBase(DebugCategory* cat)
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{
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// Make sure Core lives at least as long any DebugCategory to
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// allow debug prints until all Debugcategories has been destructed
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Core::getInstance();
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DebugManager::getInstance().registerCategory(*cat);
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}
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void DebugRegisterBase::unregister(DebugCategory* cat)
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{
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DebugManager::getInstance().unregisterCategory(*cat);
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}
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static color_value selectColor(const DebugCategory::level msgLevel)
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{
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switch(msgLevel) {
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case DebugCategory::LTRACE:
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return COLOR_GREY;
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case DebugCategory::LDEBUG:
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return COLOR_LIGHTBLUE;
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case DebugCategory::LINFO:
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return COLOR_CYAN;
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case DebugCategory::LWARNING:
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return COLOR_YELLOW;
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case DebugCategory::LERROR:
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return COLOR_LIGHTRED;
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}
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return COLOR_WHITE;
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}
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#if __GNUC__
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// Allow gcc to optimize tls access. It also makes sure initialized is done as
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// early as possible. The early initialization helps to give threads same ids as
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// gdb shows.
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#define EXEC_ATTR __attribute__((tls_model("initial-exec")))
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#else
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#define EXEC_ATTR
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#endif
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namespace {
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static std::atomic<uint32_t> nextId{0};
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static EXEC_ATTR thread_local uint32_t thread_id{nextId.fetch_add(1)+1};
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}
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DebugCategory::ostream_proxy_prefix::ostream_proxy_prefix(
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const DebugCategory& cat,
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color_ostream& target,
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const DebugCategory::level msgLevel) :
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color_ostream_proxy(target)
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{
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color(selectColor(msgLevel));
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auto now = std::chrono::system_clock::now();
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tm local{};
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//! \todo c++ 2020 will have std::chrono::to_stream(fmt, system_clock::now())
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//! but none implements it yet.
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std::time_t now_c = std::chrono::system_clock::to_time_t(now);
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auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(now.time_since_epoch()) % 1000;
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// Output time in format %02H:%02M:%02S.%03ms
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#if __GNUC__ < 5
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// Fallback for gcc 4
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char buffer[32];
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size_t sz = strftime(buffer, sizeof(buffer)/sizeof(buffer[0]),
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"%T.", localtime_r(&now_c, &local));
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*this << (sz > 0 ? buffer : "HH:MM:SS.")
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#else
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*this << std::put_time(localtime_r(&now_c, &local),"%T.")
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#endif
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<< std::setfill('0') << std::setw(3) << ms.count()
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// Thread id is allocated in the thread creation order to a thread_local
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// variable
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<< ":t" << thread_id
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// Output plugin and category names to make it easier to locate where
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// the message is coming. It would be easy replaces these with __FILE__
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// and __LINE__ passed from the macro if that would be preferred prefix.
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<< ':' << cat.plugin() << ':' << cat.category() << ": ";
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}
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DebugCategory::level DebugCategory::allowed() const noexcept
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{
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return allowed_.load(std::memory_order_relaxed);
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}
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void DebugCategory::allowed(DebugCategory::level value) noexcept
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{
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level old = allowed_.exchange(value, std::memory_order_relaxed);
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if (old == value)
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return;
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TRACE(debug) << "modify DebugCategory '" << category()
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<< "' from '" << plugin()
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<< "' allowed " << value << std::endl;
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auto& manager = DebugManager::getInstance();
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manager.categorySignal(DebugManager::CAT_MODIFIED, *this);
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}
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DebugCategory::cstring_ref DebugCategory::category() const noexcept
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{
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return category_;
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}
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DebugCategory::cstring_ref DebugCategory::plugin() const noexcept
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{
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return plugin_;
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}
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#if __cplusplus < 201703L && __cpp_lib_atomic_is_always_lock_free < 201603
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//! C++17 has std::atomic::is_always_lock_free for static_assert. Older
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//! standards only provide runtime checks if an atomic type is lock free
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struct failIfEnumAtomicIsNotLockFree {
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failIfEnumAtomicIsNotLockFree() {
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std::atomic<DebugCategory::level> test;
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if (test.is_lock_free())
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return;
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std::cerr << __FILE__ << ':' << __LINE__
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<< ": error: std::atomic<DebugCategory::level> should be lock free. Your compiler reports the atomic requires runtime locks. Either you are using a very old CPU or we need to change code to use integer atomic type." << std::endl;
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std::abort();
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}
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} failIfEnumAtomicIsNotLockFree;
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#endif
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}
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@ -0,0 +1,369 @@
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/**
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Copyright © 2018 Pauli <suokkos\gmail.com>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any
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damages arising from the use of this software.
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Permission is granted to anyone to use this software for any
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purpose, including commercial applications, and to alter it and
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redistribute it freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must
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not claim that you wrote the original software. If you use this
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software in a product, an acknowledgment in the product
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documentation would be appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and
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must not be misrepresented as being the original software.
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3. This notice may not be removed or altered from any source
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distribution.
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*/
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#pragma once
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#include "ColorText.h"
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#include <atomic>
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#include "Core.h"
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namespace DFHack {
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/*! \file Debug.h
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* Light weight wrappers to runtime debug output filtering. Idea is to add as
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* little as possible code compared to debug output without filtering. The
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* effect is archived using #TRACE, #DEBUG, #INFO, #WARN and #ERR macros. They
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* "return" color_ostream object or reference that can be then used normally for
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* either printf or stream style debug output.
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*
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* Internally macros do inline filtering check which allows compiler to have a
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* fast path without debug output only checking unlikely condition. But if
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* output is enabled then runtime code will jump to debug printing function
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* calls. The macro setup code will also print standardized leading part of
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* debug string including time stamp, plugin name and debug category name.
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*
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* \code{.cpp}
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* #include "Debug.h"
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* DBG_DECLARE(myplugin,init);
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*
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* DFhackCExport command_result plugin_init ( color_ostream &out, std::vector <PluginCommand> &commands)
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* {
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* command_result rv = CR_OK;
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* DEBUG(init, out).print("initializing\n")
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* if ((rv = initWork()) != CR_OK) {
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* ERR(init, out) << "initWork failed with "
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* << rv << " error code" << std::endl;
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* return rv;
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* }
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* return rv
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* }
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* \endcode
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*
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* The debug print filtering levels can be changed using debugger. Following
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* gdb example would automatically setup core/init and core/render to trace
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* level when SDL_init is called.
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*
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* \code{.unparsed}
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* break SDL_init
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* commands
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* silent
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* p DFHack::debug::core::debug_init.allowed_ = 0
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* p DFHack::debug::core::debug_render.allowed_ = 0
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* c
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* end
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* \endcode
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*
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*/
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#ifndef __has_cpp_attribute
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#define __has_cpp_attribute(x) 0
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#endif
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/*!
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* \defgroup debug_branch_prediction Branch prediction helper macros
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* Helper macro tells compiler that debug output branch is unlikely and should
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* be optimized to cold section of the function.
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* \{
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*/
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#if __cplusplus >= 202000L || __has_cpp_attribute(likely)
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// c++20 will have standard branch prediction hint attributes
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#define likely(x) (x) [[likely]]
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#define unlikely(x) (x) [[unlikely]]
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#elif defined(__GNUC__)
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// gcc has builtin functions that give hints to the branch prediction
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#define likely(x) (__builtin_expect(!!(x), 1))
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#define unlikely(x) (__builtin_expect(!!(x), 0))
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#else
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#define likely(x) (x)
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#define unlikely(x) (x)
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#endif
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//! \}
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#ifdef NDEBUG
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//! Reduce minimum compiled in debug levels if NDEBUG is defined
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#define DBG_FILTER DFHack::DebugCategory::LINFO
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#else
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//! Set default compiled in debug levels to include all prints
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#define DBG_FILTER DFHack::DebugCategory::LTRACE
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#endif
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/*!
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* DebugCategory is used to enable and disable debug messages in runtime.
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* Declaration and definition are handled by #DBG_DECLARE and #DBG_DEFINE
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* macros. Runtime filtering support is handled by #TRACE, #DEBUG, #INFO, #WARN
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* and #ERR macros.
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*/
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class DFHACK_EXPORT DebugCategory final {
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public:
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//! type helper to maybe make it easier to convert to std::string_view when
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//! c++17 can be required.
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using cstring = const char*;
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using cstring_ref = const char*;
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/*!
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* Debug level enum for message filtering
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*/
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enum level {
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LTRACE = 0,
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LDEBUG = 1,
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LINFO = 2,
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LWARNING = 3,
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LERROR = 4,
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};
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/*!
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* \param plugin the name of plugin the category belongs to
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* \param category the name of category
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* \param defaultLevel optional default filtering level for the category
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*/
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constexpr DebugCategory(cstring_ref plugin,
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cstring_ref category,
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level defaultLevel = LWARNING) noexcept :
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plugin_{plugin},
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category_{category},
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allowed_{defaultLevel}
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{}
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DebugCategory(const DebugCategory&) = delete;
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DebugCategory(DebugCategory&&) = delete;
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DebugCategory& operator=(DebugCategory) = delete;
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DebugCategory& operator=(DebugCategory&&) = delete;
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/*!
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* Used by debug macros to check if message should be printed.
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*
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* It is defined in the header to allow compiler inline it and make disabled
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* state a fast path without function calls.
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*
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* \param msgLevel the debug message level the following print belongs to
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* \return boolean with true indicating that message should be printed
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*/
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bool isEnabled(const level msgLevel) const noexcept {
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const uint32_t intLevel = static_cast<uint32_t>(msgLevel);
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// Compile time filtering to allow compiling out debug checks prints
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// from binary.
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return static_cast<uint32_t>(DBG_FILTER) <= intLevel &&
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// Runtime filtering for debug messages
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static_cast<uint32_t>(allowed_.load(std::memory_order_relaxed)) <= intLevel;
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}
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struct DFHACK_EXPORT ostream_proxy_prefix : public color_ostream_proxy {
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ostream_proxy_prefix(const DebugCategory& cat,
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color_ostream& target,
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DebugCategory::level level);
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~ostream_proxy_prefix()
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{
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flush();
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}
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};
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/*!
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* Fetch a steam object proxy object for output. It also adds standard
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* message components like time and plugin and category names to the line.
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*
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* User must make sure that the line is terminated with a line end.
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*
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* \param msgLevel Specifies the level which next debug message belongs
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* \return color_ostream_proxy that can be used to print the message
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* \sa DFHack::Core::getConsole()
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*/
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ostream_proxy_prefix getStream(const level msgLevel) const
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{
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return {*this,Core::getInstance().getConsole(),msgLevel};
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}
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/*!
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* Add standard message components to existing output stream object to begin
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* a new message line to an shared buffered object.
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*
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* \param msgLevel Specifies the level which next debug message belongs
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* \param target An output stream object where a debug output is printed
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* \return color_ostream reference that was passed as second parameter
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*/
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ostream_proxy_prefix getStream(const level msgLevel, color_ostream& target) const
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{
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return {*this,target,msgLevel};
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}
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/*!
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* \brief Allow management code to set a new filtering level
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* Caller must have locked DebugManager::access_mutex_.
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*/
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void allowed(level value) noexcept;
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//! Query current filtering level
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level allowed() const noexcept;
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//! Query plugin name
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cstring_ref plugin() const noexcept;
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//! Query category name
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cstring_ref category() const noexcept;
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private:
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cstring plugin_;
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cstring category_;
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std::atomic<level> allowed_;
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#if __cplusplus >= 201703L || __cpp_lib_atomic_is_always_lock_free >= 201603
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static_assert(std::atomic<level>::is_always_lock_free,
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"std::atomic<level> should be lock free. You are using a very old CPU or code needs to use std::atomic<int>");
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#endif
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};
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/**
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* Handle actual registering wrong template parameter generated pointer
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* calculation.
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*/
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class DFHACK_EXPORT DebugRegisterBase {
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protected:
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DebugRegisterBase(DebugCategory* category);
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void unregister(DebugCategory* category);
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};
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/**
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* Register DebugCategory to DebugManager
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*/
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template<DebugCategory* category>
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class DebugRegister final : public DebugRegisterBase {
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public:
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DebugRegister() :
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DebugRegisterBase{category}
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{}
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~DebugRegister() {
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unregister(category);
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}
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};
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#define DBG_NAME(category) debug_ ## category
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/*!
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* Declares a debug category. There must be only a declaration per category.
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* Declaration should be in same plugin where it is used. If same category name
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* is used in core and multiple plugins they all are changed with same command
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* unless user specifies explicitly plugin name.
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*
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* Must be used in one translation unit only.
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*
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* \param plugin the name of plugin where debug category is used
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* \param category the name of category
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* \param level the initial DebugCategory::level filtering level.
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*/
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#define DBG_DECLARE(plugin,category, ...) \
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namespace debug { namespace plugin { \
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DebugCategory DBG_NAME(category){#plugin,#category,__VA_ARGS__}; \
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DebugRegister<&DBG_NAME(category)> register_ ## category; \
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} } \
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using debug::plugin::DBG_NAME(category)
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/*!
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* Can be used to access a shared DBG_DECLARE category. But may not be used from
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* static initializer because translation unit order is undefined.
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*
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* Can be used in shared headers to gain access to one definition from
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* DBG_DECLARE.
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* \param plugin The plugin name that must match DBG_DECLARE
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* \param category The category name that must matnch DBG_DECLARE
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*/
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#define DBG_EXTERN(plugin,category) \
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namespace debug { namespace plugin { \
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extern DFHack::DebugCategory DBG_NAME(category); \
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} } \
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using debug::plugin::DBG_NAME(category)
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#define DBG_PRINT(category,pred,level,...) \
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if pred(!DFHack::DBG_NAME(category).isEnabled(level)) \
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; /* nop fast path when debug category is disabled */ \
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else /* else to allow macro use in if-else branches */ \
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DFHack::DBG_NAME(category).getStream(level, ## __VA_ARGS__) \
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/* end of DBG_PRINT */
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/*!
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||||
* Open a line for trace level debug output if enabled
|
||||
*
|
||||
* Preferred category for inside loop debug messages or callbacks/methods called
|
||||
* multiple times per second. Good example would be render or onUpdate methods.
|
||||
*
|
||||
* \param category the debug category
|
||||
* \param optional the optional second parameter is an existing
|
||||
* color_ostream_proxy object
|
||||
* \return color_ostream object that can be used for stream output
|
||||
*/
|
||||
#define TRACE(category, ...) DBG_PRINT(category, likely, \
|
||||
DFHack::DebugCategory::LTRACE, ## __VA_ARGS__)
|
||||
|
||||
/*!
|
||||
* Open a line for debug level debug output if enabled
|
||||
*
|
||||
* Preferred place to use it would be commonly called functions that don't fall
|
||||
* into trace category.
|
||||
*
|
||||
* \param category the debug category
|
||||
* \param optional the optional second parameter is an existing
|
||||
* color_ostream_proxy object
|
||||
* \return color_ostream object that can be used for stream output
|
||||
*/
|
||||
#define DEBUG(category, ...) DBG_PRINT(category, likely, \
|
||||
DFHack::DebugCategory::LDEBUG, ## __VA_ARGS__)
|
||||
|
||||
/*!
|
||||
* Open a line for error level debug output if enabled
|
||||
*
|
||||
* Important debug messages when some rarely changed state changes. Example
|
||||
* would be when a debug category filtering level changes.
|
||||
*
|
||||
* \param category the debug category
|
||||
* \param optional the optional second parameter is an existing
|
||||
* color_ostream_proxy object
|
||||
* \return color_ostream object that can be used for stream output
|
||||
*/
|
||||
#define INFO(category, ...) DBG_PRINT(category, likely, \
|
||||
DFHack::DebugCategory::LINFO, ## __VA_ARGS__)
|
||||
|
||||
/*!
|
||||
* Open a line for warning level debug output if enabled
|
||||
*
|
||||
* Warning category is for recoverable errors. This generally signals that
|
||||
* something unusual happened but there is code handling the error which should
|
||||
* allow df continue running without issues.
|
||||
*
|
||||
* \param category the debug category
|
||||
* \param optional the optional second parameter is an existing
|
||||
* color_ostream_proxy object
|
||||
* \return color_ostream object that can be used for stream output
|
||||
*/
|
||||
#define WARN(category, ...) DBG_PRINT(category, unlikely, \
|
||||
DFHack::DebugCategory::LWARNING, ## __VA_ARGS__)
|
||||
|
||||
/*!
|
||||
* Open a line for error level error output if enabled
|
||||
*
|
||||
* Errors should be printed only for cases where plugin or dfhack can't recover
|
||||
* from reported error and it requires manual handling from the user.
|
||||
*
|
||||
* \param category the debug category
|
||||
* \param optional the optional second parameter is an existing
|
||||
* color_ostream_proxy object
|
||||
* \return color_ostream object that can be used for stream output
|
||||
*/
|
||||
#define ERR(category, ...) DBG_PRINT(category, unlikely, \
|
||||
DFHack::DebugCategory::LERROR, ## __VA_ARGS__)
|
||||
|
||||
}
|
||||
@ -0,0 +1,111 @@
|
||||
/**
|
||||
Copyright © 2018 Pauli <suokkos@gmail.com>
|
||||
|
||||
This software is provided 'as-is', without any express or implied
|
||||
warranty. In no event will the authors be held liable for any
|
||||
damages arising from the use of this software.
|
||||
|
||||
Permission is granted to anyone to use this software for any
|
||||
purpose, including commercial applications, and to alter it and
|
||||
redistribute it freely, subject to the following restrictions:
|
||||
|
||||
1. The origin of this software must not be misrepresented; you must
|
||||
not claim that you wrote the original software. If you use this
|
||||
software in a product, an acknowledgment in the product
|
||||
documentation would be appreciated but is not required.
|
||||
|
||||
2. Altered source versions must be plainly marked as such, and
|
||||
must not be misrepresented as being the original software.
|
||||
|
||||
3. This notice may not be removed or altered from any source
|
||||
distribution.
|
||||
*/
|
||||
|
||||
#pragma once
|
||||
|
||||
#include "Export.h"
|
||||
#include "Signal.hpp"
|
||||
|
||||
#include <mutex>
|
||||
#include <vector>
|
||||
|
||||
namespace DFHack {
|
||||
|
||||
/*! \file DebugManager.h
|
||||
* Expose an simple interface to runtime debug output filtering. The management
|
||||
* interface is separated from output interface because output is required in
|
||||
* many places while management is expected to be required only in a few places.
|
||||
*/
|
||||
|
||||
class DebugCategory;
|
||||
|
||||
/*!
|
||||
* \brief Container holding all registered runtime debug categories
|
||||
* Singleton DebugManager is a minor extension to std::vector that allows signal
|
||||
* callbacks to be attached from ui code that manages.
|
||||
*
|
||||
* To avoid parallel plugin unload causing issues access to DebugManager must be
|
||||
* protected by mutex. The access mutex will be taken when
|
||||
* DFHack::DebugCategory::~DebugCategory performs unregister calls to
|
||||
* DFHack::DebugManager. The mutex will protect from memory disappearing while
|
||||
* ui code is accessing or changing the runtime state.
|
||||
*
|
||||
* Signal emitting happens from a locked contexts. Taking the
|
||||
* DFHack::DebugManager::access_mutex_ in a signal callback will results to a
|
||||
* deadlock.
|
||||
*
|
||||
* The interface is extremely simple but enough to implement persistent filter
|
||||
* states and runtime configuration code in a plugin.
|
||||
*/
|
||||
class DFHACK_EXPORT DebugManager : public std::vector<DebugCategory*> {
|
||||
public:
|
||||
friend class DebugRegisterBase;
|
||||
|
||||
//! access_mutex_ protects all readers and writers to DFHack::DebugManager
|
||||
std::mutex access_mutex_;
|
||||
|
||||
//! Different signals that all will be routed to
|
||||
//! DebugManager::categorySignal
|
||||
enum signalType {
|
||||
CAT_ADD,
|
||||
CAT_REMOVE,
|
||||
CAT_MODIFIED,
|
||||
};
|
||||
|
||||
//! type to help access signal features like Connection and BlockGuard
|
||||
using categorySignal_t = Signal<void (signalType, DebugCategory&)>;
|
||||
|
||||
/*!
|
||||
* Signal object where callbacks can be connected. Connecting to a class
|
||||
* method can use a lambda wrapper to the capture object pointer and correctly
|
||||
* call required method.
|
||||
*
|
||||
* Signal is internally serialized allowing multiple threads call it
|
||||
* freely.
|
||||
*/
|
||||
categorySignal_t categorySignal;
|
||||
|
||||
//! Get the singleton object
|
||||
static DebugManager& getInstance() {
|
||||
static DebugManager instance;
|
||||
return instance;
|
||||
}
|
||||
|
||||
//! Prevent copies
|
||||
DebugManager(const DebugManager&) = delete;
|
||||
//! Prevent copies
|
||||
DebugManager(DebugManager&&) = delete;
|
||||
//! Prevent copies
|
||||
DebugManager& operator=(DebugManager) = delete;
|
||||
//! Prevent copies
|
||||
DebugManager& operator=(DebugManager&&) = delete;
|
||||
protected:
|
||||
DebugManager() = default;
|
||||
|
||||
//! Helper for automatic category registering and signaling
|
||||
void registerCategory(DebugCategory &);
|
||||
//! Helper for automatic category unregistering and signaling
|
||||
void unregisterCategory(DebugCategory &);
|
||||
private:
|
||||
};
|
||||
}
|
||||
@ -0,0 +1,782 @@
|
||||
/**
|
||||
Copyright © 2018 Pauli <suokkos@gmail.com>
|
||||
|
||||
This software is provided 'as-is', without any express or implied
|
||||
warranty. In no event will the authors be held liable for any
|
||||
damages arising from the use of this software.
|
||||
|
||||
Permission is granted to anyone to use this software for any
|
||||
purpose, including commercial applications, and to alter it and
|
||||
redistribute it freely, subject to the following restrictions:
|
||||
|
||||
1. The origin of this software must not be misrepresented; you must
|
||||
not claim that you wrote the original software. If you use this
|
||||
software in a product, an acknowledgment in the product
|
||||
documentation would be appreciated but is not required.
|
||||
|
||||
2. Altered source versions must be plainly marked as such, and
|
||||
must not be misrepresented as being the original software.
|
||||
|
||||
3. This notice may not be removed or altered from any source
|
||||
distribution.
|
||||
*/
|
||||
|
||||
#pragma once
|
||||
|
||||
#include <climits>
|
||||
|
||||
#include <atomic>
|
||||
#include <functional>
|
||||
#include <list>
|
||||
#include <memory>
|
||||
#include <mutex>
|
||||
|
||||
#ifdef __SSE__
|
||||
#include <xmmintrin.h>
|
||||
#endif
|
||||
|
||||
namespace DFHack {
|
||||
|
||||
/*!
|
||||
* Select inline implementation for Signal members
|
||||
* This requires careful destruction order where all connection has been
|
||||
* disconnected before Signal::~Signal()
|
||||
*/
|
||||
class signal_inline_tag;
|
||||
/*!
|
||||
* Select share_ptr managed implementation for Signal members.
|
||||
*
|
||||
* If Connection holding object may be deleted without full serialization
|
||||
* between disconnect and signal emit the holding object must be managed by
|
||||
* shared_ptr and derive from ConnectedBase. It will also have to pass the
|
||||
* std::shared_ptr<ConnectedBase> to connect.
|
||||
|
||||
* It uses two way std::weak_ptr reference to guarantee destruction of either
|
||||
* object doesn't happen when call is made to them.
|
||||
*
|
||||
* It is still possible to get a callback call after manual disconnect from
|
||||
* outside destructor. But without destruction risk the disconnect race can be
|
||||
* handled by slot implementation side.
|
||||
*/
|
||||
class signal_shared_tag;
|
||||
|
||||
/**
|
||||
* Used for signal_shared_tag holders that may race with destructor triggered
|
||||
* disconnect and emit from Signal.
|
||||
*/
|
||||
class ConnectedBase {
|
||||
};
|
||||
|
||||
template<typename Signature, typename tag = signal_inline_tag>
|
||||
class Signal;
|
||||
|
||||
namespace details {
|
||||
|
||||
template<typename Signature, typename tag>
|
||||
struct SignalImpl;
|
||||
|
||||
template<typename Signature, typename tag>
|
||||
struct selectImpl;
|
||||
|
||||
//! Manage callback states in thread safe manner
|
||||
template<typename Signature, typename tag>
|
||||
class CallbackHolderImpl;
|
||||
|
||||
template<typename RT, typename... Args>
|
||||
struct CallbackHolderBase {
|
||||
using Callback = std::function<RT(Args...)>;
|
||||
|
||||
CallbackHolderBase(const Callback& cb) :
|
||||
cb_{cb},
|
||||
state_{}
|
||||
{}
|
||||
|
||||
//! Block the connection
|
||||
void block() noexcept
|
||||
{
|
||||
state_ += blocked;
|
||||
}
|
||||
|
||||
//! Unblock the connection
|
||||
void unblock() noexcept
|
||||
{
|
||||
state_ -= blocked;
|
||||
}
|
||||
|
||||
//! Check if connection is deleted
|
||||
bool erased() const noexcept
|
||||
{
|
||||
return state_ & deleted;
|
||||
}
|
||||
|
||||
//! Check if connection is still active (not blocked or erased)
|
||||
operator bool() const noexcept
|
||||
{
|
||||
return !(state_ & ~inCall);
|
||||
}
|
||||
|
||||
protected:
|
||||
//! Immutable callback object
|
||||
const Callback cb_;
|
||||
using state_t = unsigned;
|
||||
//! Single shared state as a bitfield to simplify synchronization
|
||||
//! between state changes.
|
||||
std::atomic<state_t> state_;
|
||||
static constexpr state_t deleted = 0x1 << (sizeof(state_t)*CHAR_BIT - 1);
|
||||
static constexpr state_t inCall = deleted >> (sizeof(state_t)*CHAR_BIT/2);
|
||||
static constexpr state_t blocked = 0x1;
|
||||
static constexpr state_t blockedMask = inCall - 1;
|
||||
static constexpr state_t inCallMask = (deleted - 1) ^ blockedMask;
|
||||
};
|
||||
|
||||
template<typename RT, typename... Args>
|
||||
class CallbackHolderImpl<RT(Args...), signal_inline_tag> :
|
||||
public CallbackHolderBase<RT, Args...> {
|
||||
using parent_t = CallbackHolderBase<RT, Args...>;
|
||||
public:
|
||||
using Callback = typename parent_t::Callback;
|
||||
private:
|
||||
using state_t = typename parent_t::state_t;
|
||||
//! Make sure callback pointed object doesn't disappear under us
|
||||
//! while we call it.
|
||||
struct CallGuard {
|
||||
|
||||
//! Prevent copies but allow copy elision
|
||||
CallGuard(const CallGuard&);
|
||||
|
||||
//! Allow implicit conversion to callback for simply syntax
|
||||
const Callback& operator*() const noexcept
|
||||
{
|
||||
return holder_->cb_;
|
||||
}
|
||||
|
||||
operator bool() const noexcept
|
||||
{
|
||||
return *holder_;
|
||||
}
|
||||
|
||||
//! Mark call not to be called any more
|
||||
~CallGuard() {
|
||||
holder_->state_ -= parent_t::inCall;
|
||||
}
|
||||
private:
|
||||
//! Reference to the connection
|
||||
CallbackHolderImpl* holder_;
|
||||
|
||||
//! Mark call to be in process
|
||||
CallGuard(CallbackHolderImpl* holder) :
|
||||
holder_{holder}
|
||||
{
|
||||
holder_->state_ += parent_t::inCall;
|
||||
}
|
||||
//! Only allow construction from the CallbackHolderImpl::prepareCall
|
||||
friend class CallbackHolderImpl;
|
||||
};
|
||||
public:
|
||||
//! Construct the callback state for a callback
|
||||
CallbackHolderImpl(const Callback& cb) :
|
||||
parent_t{cb}
|
||||
{}
|
||||
|
||||
/*!
|
||||
* Data race free disconnection for the connection. It spins until
|
||||
* no more callers to wait. Spinning should be problem as callbacks
|
||||
* are expected to be simple and fast to execute.
|
||||
*
|
||||
* Must not be called from withing callback!
|
||||
*
|
||||
* \todo Maybe use monitor instruction to avoid busy wait and call
|
||||
* std::thread::yield() if wait is longer than expected.
|
||||
*/
|
||||
void erase() noexcept
|
||||
{
|
||||
state_t oldstate;
|
||||
state_t newstate;
|
||||
/** Spin until no callers to this callback */
|
||||
spin:
|
||||
while ((oldstate = parent_t::state_) & parent_t::inCallMask) {
|
||||
// pause would be portable to all old processors but there
|
||||
// isn't portable way to generate it without SSE header.
|
||||
#ifdef __SSE__
|
||||
_mm_pause();
|
||||
#endif
|
||||
}
|
||||
do {
|
||||
if (oldstate & parent_t::inCallMask)
|
||||
goto spin;
|
||||
newstate = oldstate | parent_t::deleted;
|
||||
} while(!parent_t::state_.compare_exchange_weak(oldstate, newstate));
|
||||
}
|
||||
|
||||
//! Return RAII CallGuard to protect race between callback and
|
||||
//! disconnect.
|
||||
CallGuard prepareCall()
|
||||
{
|
||||
return {this};
|
||||
}
|
||||
};
|
||||
|
||||
template<typename RT, typename... Args>
|
||||
class CallbackHolderImpl<RT(Args...), signal_shared_tag> :
|
||||
public CallbackHolderBase<RT, Args...> {
|
||||
using parent_t = CallbackHolderBase<RT, Args...>;
|
||||
public:
|
||||
using Callback = typename parent_t::Callback;
|
||||
private:
|
||||
using state_t = typename parent_t::state_t;
|
||||
//! Make sure callback pointed object doesn't disappear under us
|
||||
//! while we call it.
|
||||
struct CallGuard {
|
||||
|
||||
//! Prevent copies but allow copy elision
|
||||
CallGuard(const CallGuard&);
|
||||
|
||||
//! Allow implicit conversion to callback for simply syntax
|
||||
const Callback& operator*() const noexcept
|
||||
{
|
||||
return holder_->cb_;
|
||||
}
|
||||
|
||||
operator bool() const noexcept
|
||||
{
|
||||
// If this is not marked erased then weak_ref->lock succeeded or
|
||||
// the slot isn't managed by shared_ptr<ConnectedBase>
|
||||
return *holder_;
|
||||
}
|
||||
|
||||
private:
|
||||
//! Reference to the connection
|
||||
CallbackHolderImpl* holder_;
|
||||
std::shared_ptr<ConnectedBase> strong_ref_;
|
||||
|
||||
//! Mark call to be in process
|
||||
CallGuard(CallbackHolderImpl* holder) :
|
||||
holder_{holder},
|
||||
strong_ref_{holder->weak_ref_.lock()}
|
||||
{
|
||||
}
|
||||
//! Only allow construction from the CallbackHolderImpl::prepareCall
|
||||
friend class CallbackHolderImpl;
|
||||
};
|
||||
|
||||
std::weak_ptr<ConnectedBase> weak_ref_;
|
||||
friend CallGuard;
|
||||
public:
|
||||
//! Construct the callback state for an automatically synchronized object
|
||||
CallbackHolderImpl(const Callback& cb,
|
||||
std::shared_ptr<ConnectedBase>& ref) :
|
||||
parent_t{cb},
|
||||
weak_ref_{ref}
|
||||
{}
|
||||
|
||||
//! Construct the callback state for an externally synchronized object
|
||||
CallbackHolderImpl(const Callback& cb) :
|
||||
parent_t{cb},
|
||||
weak_ref_{}
|
||||
{}
|
||||
|
||||
/*!
|
||||
* erase from destructor can't happen while we are in call because
|
||||
*/
|
||||
void erase() noexcept
|
||||
{
|
||||
parent_t::state_ |= parent_t::deleted;
|
||||
}
|
||||
|
||||
//! Return RAII CallGuard to protect race between callback and
|
||||
//! disconnect.
|
||||
CallGuard prepareCall()
|
||||
{
|
||||
return {this};
|
||||
}
|
||||
};
|
||||
|
||||
template<typename RT, typename... Args, typename tag>
|
||||
struct SignalImpl<RT(Args...), tag> : public selectImpl<RT(Args...), tag>::parent_t {
|
||||
protected:
|
||||
using select_t = selectImpl<RT(Args...), tag>;
|
||||
using parent_t = typename select_t::parent_t;
|
||||
public:
|
||||
using CallbackHolder = CallbackHolderImpl<RT(Args...), tag>;
|
||||
using Callback = typename CallbackHolder::Callback;
|
||||
|
||||
//! The container type used to store callbacks
|
||||
using CallbackContainer = std::list<CallbackHolder>;
|
||||
struct BlockGuard;
|
||||
|
||||
//! Simple connection class that is required to disconnect from the
|
||||
//! signal.
|
||||
struct Connection {
|
||||
//! Construct a default Connection object but using it will result
|
||||
//! to undefined behavior unless proper connection is assigned to it
|
||||
Connection() = default;
|
||||
|
||||
Connection(Connection&& o) :
|
||||
iter_{o.iter_},
|
||||
signal_{}
|
||||
{
|
||||
std::swap(signal_, o.signal_);
|
||||
}
|
||||
|
||||
Connection& operator=(Connection&& o)
|
||||
{
|
||||
disconnect();
|
||||
iter_ = o.iter_;
|
||||
std::swap(signal_, o.signal_);
|
||||
return *this;
|
||||
}
|
||||
|
||||
Connection(const Connection&) = delete;
|
||||
Connection& operator=(const Connection&) = delete;
|
||||
|
||||
//! Disconnect from signal
|
||||
void disconnect()
|
||||
{
|
||||
auto s = select_t::lock(signal_);
|
||||
if (!s)
|
||||
return;
|
||||
|
||||
s->disconnect(*this);
|
||||
}
|
||||
|
||||
~Connection()
|
||||
{
|
||||
disconnect();
|
||||
}
|
||||
private:
|
||||
//! Block the connection temporary
|
||||
void block()
|
||||
{
|
||||
auto s = select_t::lock(signal_);
|
||||
if (!s)
|
||||
return;
|
||||
iter_->block();
|
||||
}
|
||||
|
||||
//! Restore blocked connection
|
||||
void unblock()
|
||||
{
|
||||
auto s = select_t::lock(signal_);
|
||||
if (!s)
|
||||
return;
|
||||
iter_->unblock();
|
||||
}
|
||||
|
||||
//! Construct connection object
|
||||
Connection(const typename CallbackContainer::iterator &iter,
|
||||
typename select_t::weak_ptr ptr) :
|
||||
iter_{iter},
|
||||
signal_{ptr}
|
||||
{}
|
||||
|
||||
//! std::list iterator that is used to access the callback and allow
|
||||
//! removal from the list.
|
||||
typename CallbackContainer::iterator iter_;
|
||||
//! Reference to signal object
|
||||
typename select_t::weak_ptr signal_;
|
||||
friend SignalImpl;
|
||||
friend BlockGuard;
|
||||
};
|
||||
|
||||
/*!
|
||||
* BlockGuard allows temporary RAII guard managed blocking of a
|
||||
* connection object.
|
||||
*/
|
||||
struct BlockGuard {
|
||||
/*!
|
||||
* Block a connection that belongs to signal
|
||||
* \param connection The connection that will be temporary blocked
|
||||
*/
|
||||
BlockGuard(Connection& connection) :
|
||||
blocked_{&connection}
|
||||
{
|
||||
connection.block();
|
||||
}
|
||||
|
||||
/*!
|
||||
* Unblock the temporary blocked connection
|
||||
*/
|
||||
~BlockGuard()
|
||||
{
|
||||
blocked_->unblock();
|
||||
}
|
||||
|
||||
//! Prevent copies but allow copy elision
|
||||
BlockGuard(const BlockGuard&);
|
||||
private:
|
||||
Connection* blocked_;
|
||||
};
|
||||
|
||||
Connection connect(const Callback& f)
|
||||
{
|
||||
std::lock_guard<std::mutex> lock(access_);
|
||||
auto iter = callbacks_.emplace(callbacks_.begin(), f);
|
||||
return {iter, parent_t::shared_from_this()};
|
||||
}
|
||||
|
||||
Connection connect(std::shared_ptr<ConnectedBase> c, const Callback& f)
|
||||
{
|
||||
std::lock_guard<std::mutex> lock(access_);
|
||||
auto iter = callbacks_.emplace(callbacks_.begin(), f, c);
|
||||
return {iter, parent_t::shared_from_this()};
|
||||
}
|
||||
|
||||
void disconnect(Connection& connection) {
|
||||
std::lock_guard<std::mutex> lock(access_);
|
||||
if (recursion_) {
|
||||
deleted_ = true;
|
||||
connection.iter_->erase();
|
||||
} else {
|
||||
callbacks_.erase(connection.iter_);
|
||||
}
|
||||
select_t::reset(connection.signal_);
|
||||
}
|
||||
|
||||
template<typename Combiner>
|
||||
void operator()(Combiner &combiner, Args&&... arg)
|
||||
{
|
||||
std::unique_lock<std::mutex> lock(access_);
|
||||
struct RecursionGuard {
|
||||
SignalImpl* signal_;
|
||||
std::unique_lock<std::mutex>* lock_;
|
||||
//! Increment access count to make sure disconnect doesn't erase
|
||||
RecursionGuard(SignalImpl *signal, std::unique_lock<std::mutex>* lock) :
|
||||
signal_{signal},
|
||||
lock_{lock}
|
||||
{
|
||||
++signal_->recursion_;
|
||||
}
|
||||
|
||||
/*!
|
||||
* Clean up deleted functions in data race free and exception
|
||||
* safe manner.
|
||||
*/
|
||||
~RecursionGuard()
|
||||
{
|
||||
lock_->lock();
|
||||
if (--signal_->recursion_ == 0 && signal_->deleted_) {
|
||||
for (auto iter = signal_->callbacks_.begin(); iter != signal_->callbacks_.end();) {
|
||||
if (iter->erased())
|
||||
iter = signal_->callbacks_.erase(iter);
|
||||
else
|
||||
++iter;
|
||||
}
|
||||
signal_->deleted_ = false;
|
||||
}
|
||||
}
|
||||
|
||||
} guard{this, &lock};
|
||||
// Call begin in locked context to allow data race free iteration
|
||||
// even if there is parallel inserts to the begin after unlocking.
|
||||
auto iter = callbacks_.begin();
|
||||
lock.unlock();
|
||||
for (; iter != callbacks_.end(); ++iter) {
|
||||
// Quickly skip blocked calls without memory writes
|
||||
if (!*iter)
|
||||
continue;
|
||||
// Protect connection from deletion while we are about to call
|
||||
// it.
|
||||
auto cb = iter->prepareCall();
|
||||
if (cb)
|
||||
combiner(*cb, std::forward<Args>(arg)...);
|
||||
}
|
||||
}
|
||||
|
||||
void operator()(Args&&... arg)
|
||||
{
|
||||
auto combiner = [](const Callback& cb, Args&&... arg2)
|
||||
{
|
||||
cb(std::forward<Args>(arg2)...);
|
||||
};
|
||||
(*this)(combiner,std::forward<Args>(arg)...);
|
||||
}
|
||||
|
||||
~SignalImpl() {
|
||||
// Check that callbacks are empty. If this triggers then signal may
|
||||
// have to be extended to allow automatic disconnection of active
|
||||
// connections in the destructor.
|
||||
if (std::is_same<tag, signal_inline_tag>::value)
|
||||
assert(callbacks_.empty() && "It is very likely that this signal should use signal_shared_tag");
|
||||
}
|
||||
|
||||
//! Simplify access to pimpl when it is inline
|
||||
SignalImpl* operator->() {
|
||||
return this;
|
||||
}
|
||||
SignalImpl& operator*() {
|
||||
return *this;
|
||||
}
|
||||
|
||||
SignalImpl() = default;
|
||||
private:
|
||||
SignalImpl(const SignalImpl&) :
|
||||
SignalImpl{}
|
||||
{}
|
||||
std::mutex access_;
|
||||
CallbackContainer callbacks_;
|
||||
int recursion_;
|
||||
bool deleted_;
|
||||
friend Signal<RT(Args...), tag>;
|
||||
};
|
||||
|
||||
template<typename RT, typename... Args>
|
||||
struct selectImpl<RT(Args...), signal_inline_tag> {
|
||||
using impl_t = SignalImpl<RT(Args...), signal_inline_tag>;
|
||||
using interface_t = Signal<RT(Args...), signal_inline_tag>;
|
||||
using type = impl_t;
|
||||
using weak_ptr = impl_t*;
|
||||
struct ptr_from_this {
|
||||
weak_ptr shared_from_this()
|
||||
{
|
||||
return static_cast<weak_ptr>(this);
|
||||
}
|
||||
};
|
||||
using parent_t = ptr_from_this;
|
||||
|
||||
selectImpl() = default;
|
||||
|
||||
// Disallow copies for inline version.
|
||||
selectImpl(const selectImpl&) = delete;
|
||||
selectImpl(selectImpl&&) = delete;
|
||||
selectImpl& operator=(const selectImpl&) = delete;
|
||||
selectImpl& operator=(selectImpl&&) = delete;
|
||||
|
||||
|
||||
static type make() {
|
||||
return {};
|
||||
}
|
||||
|
||||
static void reset(weak_ptr& ptr) {
|
||||
ptr = nullptr;
|
||||
}
|
||||
|
||||
static weak_ptr lock(weak_ptr& ptr) {
|
||||
return ptr;
|
||||
}
|
||||
|
||||
static weak_ptr get(interface_t& signal) {
|
||||
return &signal.pimpl;
|
||||
}
|
||||
};
|
||||
|
||||
template<typename RT, typename... Args>
|
||||
struct selectImpl<RT(Args...), signal_shared_tag> {
|
||||
using impl_t = SignalImpl<RT(Args...), signal_shared_tag>;
|
||||
using interface_t = Signal<RT(Args...), signal_shared_tag>;
|
||||
using type = std::shared_ptr<impl_t>;
|
||||
using weak_ptr = std::weak_ptr<impl_t>;
|
||||
using parent_t = std::enable_shared_from_this<impl_t>;
|
||||
|
||||
// Allow copies for shared version
|
||||
|
||||
static type make() {
|
||||
return std::make_shared<SignalImpl<RT(Args...), signal_shared_tag>>();
|
||||
}
|
||||
|
||||
static void reset(weak_ptr& ptr) {
|
||||
ptr.reset();
|
||||
}
|
||||
|
||||
static type lock(weak_ptr& ptr) {
|
||||
return ptr.lock();
|
||||
}
|
||||
|
||||
static weak_ptr get(interface_t& signal) {
|
||||
return signal.pimpl;
|
||||
}
|
||||
};
|
||||
}
|
||||
|
||||
/*!
|
||||
* As I couldn't figure out which signal library would be a good. Too bad all
|
||||
* signal libraries seem to be either heavy with unnecessary features or written
|
||||
* before C++11/14 have become useable targets. That seems to indicate everyone
|
||||
* is now building signal system with standard components.
|
||||
*
|
||||
* Implementation and interface is build around std::function holding delegates
|
||||
* to a function pointer or a functor. One can put there example lambda function
|
||||
* that captures this pointer from connect side. The lambda function then calls
|
||||
* the slot method of object correctly.
|
||||
*
|
||||
* It is fairly simple to change the signal signature to directly call methods
|
||||
* but internally that std::function becomes more complex. The pointer to
|
||||
* member function is problematic because multiple inheritance requires
|
||||
* adjustments to this. The lambda capture approach should be easy to use while
|
||||
* letting compiler optimize method call in the callee side.
|
||||
*
|
||||
* DFHack::Signal::Connection is an connection handle. The handle can be used to
|
||||
* disconnect and block a callback. Connection destructor will automatically
|
||||
* disconnect from the signal.
|
||||
*
|
||||
* DFHack::Signal::BlockGuard is an automatic blocked callback guard object. It
|
||||
* prevents any signals from calling the slot as long the BlockGuard object is
|
||||
* alive. Internally it replaces the callback with an empty callback and stores
|
||||
* the real callback in a member variable. Destructor then puts back the real
|
||||
* callback. This allows easily recursive BlockGuard work correctly because only
|
||||
* the first BlockGuard has the real callback.
|
||||
*
|
||||
* signal_inline_tag requires careful destruction order where all connection are
|
||||
* disconnected before signal destruction. The implementation is specifically
|
||||
* targeting places like static and singleton variables and widget hierarchies.
|
||||
* It provides data race free connect, disconnect and emit operations.
|
||||
*
|
||||
* signal_shared_tag allows a bit more freedom when destroying the Signal. It
|
||||
* adds data race safety between Connection, BlockGuard and destructor. If
|
||||
* multiple callers need access to Signal with potential of destruction of
|
||||
* original owner then callers can use Signal copy constructor to take a strong
|
||||
* reference managed by shared_ptr or weak_ptr with Signal::weak_from_this().
|
||||
* weak_from_this returns an object that forwards call directly to
|
||||
* implementation when the shared_ptr is created using Signal::lock
|
||||
*
|
||||
* \param RT return type is derived from a single signature template argument
|
||||
* \param Args Variable argument type list that is derived from a signature
|
||||
* template argument.
|
||||
* \param tag The tag type which selects between shared_ptr managed pimpl and
|
||||
* inline member variables.
|
||||
*/
|
||||
template<typename RT, typename... Args, typename tag>
|
||||
class Signal<RT(Args...), tag> : protected details::selectImpl<RT(Args...), tag> {
|
||||
public:
|
||||
//! Type of callable that can be connected to the signal.
|
||||
using Callback = std::function<RT(Args...)>;
|
||||
|
||||
protected:
|
||||
using select_t = details::selectImpl<RT(Args...), tag>;
|
||||
using CallbackContainer = typename select_t::impl_t::CallbackContainer;
|
||||
public:
|
||||
using weak_ptr = typename select_t::weak_ptr;
|
||||
|
||||
/*!
|
||||
* Simple connection class that is required to disconnect from the
|
||||
* signal.
|
||||
* \sa SignalImpl::Connection
|
||||
*/
|
||||
using Connection = typename select_t::impl_t::Connection;
|
||||
/*!
|
||||
* BlockGuard allows temporary RAII guard managed blocking of a
|
||||
* connection object.
|
||||
* \sa SignalImpl::BlockGuard
|
||||
*/
|
||||
using BlockGuard = typename select_t::impl_t::BlockGuard;
|
||||
|
||||
/*!
|
||||
* Connect a callback function to the signal
|
||||
*
|
||||
* Safe to call from any context as long as SignalImpl destructor can't be
|
||||
* called simultaneously from other thread.
|
||||
*
|
||||
* \param f callable that will connected to the signal
|
||||
* \return connection handle that can be used to disconnect it
|
||||
*/
|
||||
Connection connect(const Callback& f)
|
||||
{
|
||||
return pimpl->connect(f);
|
||||
}
|
||||
|
||||
/*!
|
||||
* Thread safe connect variant connection and Connected object destruction
|
||||
* can't race with emit from different threads.
|
||||
*
|
||||
* Safe to call from any context as long as SignalImpl destructor can't be
|
||||
* called simultaneously from other thread.
|
||||
*/
|
||||
Connection connect(std::shared_ptr<ConnectedBase> c, const Callback& f)
|
||||
{
|
||||
static_assert(std::is_same<tag, signal_shared_tag>::value,
|
||||
"Race free destruction is only possible with signal_shared_tag");
|
||||
return pimpl->connect(c, f);
|
||||
}
|
||||
|
||||
/*!
|
||||
* Disconnection a callback from slots
|
||||
*
|
||||
* signal_inline_tag:
|
||||
* This may not be called if the callback has been called in same
|
||||
* thread. If callback should trigger destruction an object then
|
||||
* deletion must use deferred. This rule prevents issues if other thread
|
||||
* are trying to call the callback when disconnecting.
|
||||
*
|
||||
* signal_shared_tag:
|
||||
* disconnect can be freely called from anywhere as long as caller holds a
|
||||
* strong reference to the Signal. Strong reference can be obtained by using
|
||||
* Connection::disconnect, Signal copy constructor to have a copy of signal
|
||||
* or weak_ptr from weak_from_this() passed to Signal::lock().
|
||||
*
|
||||
* \param connection the object returned from DFHack::Signal::connect
|
||||
*/
|
||||
void disconnect(Connection& connection)
|
||||
{
|
||||
pimpl->disconnect(connection);
|
||||
}
|
||||
|
||||
/*!
|
||||
* Call all connected callbacks using passed arguments.
|
||||
*
|
||||
* signal_inline_tag:
|
||||
* Must not call operator() from callbacks.
|
||||
* Must not disconnect called callback from inside callback. Solution often
|
||||
* is to set just atomic state variables in callback and do actual
|
||||
* processing including deletion in update handler or logic vmethod.
|
||||
*
|
||||
* signal_shared_tag:
|
||||
* Safe to call from any context as long as SignalImpl destructor can't be
|
||||
* called simultaneously from other thread.
|
||||
* Safe to disconnect any connection from callbacks.
|
||||
*
|
||||
* \param combiner that calls callbacks and processes return values
|
||||
* \param arg arguments list defined by template parameter signature.
|
||||
*/
|
||||
template<typename Combiner>
|
||||
void operator()(Combiner &combiner, Args&&... arg)
|
||||
{
|
||||
(*pimpl)(combiner, std::forward<Args>(arg)...);
|
||||
}
|
||||
|
||||
/*!
|
||||
* Call all connected callbacks using passed arguments.
|
||||
*
|
||||
* signal_inline_tag:
|
||||
* Must not call operator() from callbacks.
|
||||
* Must not disconnect called callback from inside callback. Solution often
|
||||
* is to set just atomic state variables in callback and do actual
|
||||
* processing including deletion in update handler or logic vmethod.
|
||||
*
|
||||
* signal_shared_tag:
|
||||
* Safe to call from any context as long as SignalImpl destructor can't be
|
||||
* called simultaneously from other thread.
|
||||
* Safe to disconnect any connection from callbacks.
|
||||
*
|
||||
* \param arg arguments list defined by template parameter signature.
|
||||
*/
|
||||
void operator()(Args&&... arg)
|
||||
{
|
||||
(*pimpl)(std::forward<Args>(arg)...);
|
||||
}
|
||||
|
||||
/*!
|
||||
* Helper to lock the weak_ptr
|
||||
*/
|
||||
static typename select_t::type lock(weak_ptr& ptr)
|
||||
{
|
||||
return select_t::lock(ptr);
|
||||
}
|
||||
|
||||
/*!
|
||||
* Helper to create a weak reference to pimpl which can be used to access
|
||||
* pimpl directly. If the tag is signal_shared_tag then it provides race
|
||||
* free access to Signal when using Signal::lock and checking returned
|
||||
* shared_ptr.
|
||||
*/
|
||||
weak_ptr weak_from_this() noexcept
|
||||
{
|
||||
return select_t::get(*this);
|
||||
}
|
||||
|
||||
Signal() :
|
||||
pimpl{select_t::make()}
|
||||
{}
|
||||
private:
|
||||
typename select_t::type pimpl;
|
||||
friend select_t;
|
||||
};
|
||||
}
|
||||
Loading…
Reference in New Issue