From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 02:47:55 +0200 Subject: Adding upstream version 124.0.1. Signed-off-by: Daniel Baumann --- media/libcubeb/src/cubeb_log.cpp | 233 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 233 insertions(+) create mode 100644 media/libcubeb/src/cubeb_log.cpp (limited to 'media/libcubeb/src/cubeb_log.cpp') diff --git a/media/libcubeb/src/cubeb_log.cpp b/media/libcubeb/src/cubeb_log.cpp new file mode 100644 index 0000000000..73b568f5cd --- /dev/null +++ b/media/libcubeb/src/cubeb_log.cpp @@ -0,0 +1,233 @@ +/* + * Copyright © 2016 Mozilla Foundation + * + * This program is made available under an ISC-style license. See the + * accompanying file LICENSE for details. + */ +#define NOMINMAX + +#include "cubeb_log.h" +#include "cubeb_ringbuffer.h" +#include "cubeb_tracing.h" +#include +#ifdef _WIN32 +#include +#else +#include +#endif + +std::atomic g_cubeb_log_level; +std::atomic g_cubeb_log_callback; + +/** The maximum size of a log message, after having been formatted. */ +const size_t CUBEB_LOG_MESSAGE_MAX_SIZE = 256; +/** The maximum number of log messages that can be queued before dropping + * messages. */ +const size_t CUBEB_LOG_MESSAGE_QUEUE_DEPTH = 40; +/** Number of milliseconds to wait before dequeuing log messages. */ +const size_t CUBEB_LOG_BATCH_PRINT_INTERVAL_MS = 10; + +void +cubeb_noop_log_callback(char const * /* fmt */, ...) +{ +} + +/** + * This wraps an inline buffer, that represents a log message, that must be + * null-terminated. + * This class should not use system calls or other potentially blocking code. + */ +class cubeb_log_message { +public: + cubeb_log_message() { *storage = '\0'; } + cubeb_log_message(char const str[CUBEB_LOG_MESSAGE_MAX_SIZE]) + { + size_t length = strlen(str); + /* paranoia against malformed message */ + assert(length < CUBEB_LOG_MESSAGE_MAX_SIZE); + if (length > CUBEB_LOG_MESSAGE_MAX_SIZE - 1) { + return; + } + PodCopy(storage, str, length); + storage[length] = '\0'; + } + char const * get() { return storage; } + +private: + char storage[CUBEB_LOG_MESSAGE_MAX_SIZE]{}; +}; + +/** Lock-free asynchronous logger, made so that logging from a + * real-time audio callback does not block the audio thread. */ +class cubeb_async_logger { +public: + /* This is thread-safe since C++11 */ + static cubeb_async_logger & get() + { + static cubeb_async_logger instance; + return instance; + } + void push(char const str[CUBEB_LOG_MESSAGE_MAX_SIZE]) + { + cubeb_log_message msg(str); + auto * owned_queue = msg_queue.load(); + // Check if the queue is being deallocated. If not, grab ownership. If yes, + // return, the message won't be logged. + if (!owned_queue || + !msg_queue.compare_exchange_strong(owned_queue, nullptr)) { + return; + } + owned_queue->enqueue(msg); + // Return ownership. + msg_queue.store(owned_queue); + } + void run() + { + assert(logging_thread.get_id() == std::thread::id()); + logging_thread = std::thread([this]() { + CUBEB_REGISTER_THREAD("cubeb_log"); + while (!shutdown_thread) { + cubeb_log_message msg; + while (msg_queue_consumer.load()->dequeue(&msg, 1)) { + cubeb_log_internal_no_format(msg.get()); + } + std::this_thread::sleep_for( + std::chrono::milliseconds(CUBEB_LOG_BATCH_PRINT_INTERVAL_MS)); + } + CUBEB_UNREGISTER_THREAD(); + }); + } + // Tell the underlying queue the producer thread has changed, so it does not + // assert in debug. This should be called with the thread stopped. + void reset_producer_thread() + { + if (msg_queue) { + msg_queue.load()->reset_thread_ids(); + } + } + void start() + { + auto * queue = + new lock_free_queue(CUBEB_LOG_MESSAGE_QUEUE_DEPTH); + msg_queue.store(queue); + msg_queue_consumer.store(queue); + shutdown_thread = false; + run(); + } + void stop() + { + assert(((g_cubeb_log_callback == cubeb_noop_log_callback) || + !g_cubeb_log_callback) && + "Only call stop after logging has been disabled."); + shutdown_thread = true; + if (logging_thread.get_id() != std::thread::id()) { + logging_thread.join(); + logging_thread = std::thread(); + auto * owned_queue = msg_queue.load(); + // Check if the queue is being used. If not, grab ownership. If yes, + // try again shortly. At this point, the logging thread has been joined, + // so nothing is going to dequeue. + // If there is a valid pointer here, then the real-time audio thread that + // logs won't attempt to write into the queue, and instead drop the + // message. + while (!msg_queue.compare_exchange_weak(owned_queue, nullptr)) { + } + delete owned_queue; + msg_queue_consumer.store(nullptr); + } + } + +private: + cubeb_async_logger() {} + ~cubeb_async_logger() + { + assert(logging_thread.get_id() == std::thread::id() && + (g_cubeb_log_callback == cubeb_noop_log_callback || + !g_cubeb_log_callback)); + if (msg_queue.load()) { + delete msg_queue.load(); + } + } + /** This is quite a big data structure, but is only instantiated if the + * asynchronous logger is used. The two pointers point to the same object, but + * the first one can be temporarily null when a message is being enqueued. */ + std::atomic *> msg_queue = {nullptr}; + + std::atomic *> msg_queue_consumer = { + nullptr}; + std::atomic shutdown_thread = {false}; + std::thread logging_thread; +}; + +void +cubeb_log_internal(char const * file, uint32_t line, char const * fmt, ...) +{ + va_list args; + va_start(args, fmt); + char msg[CUBEB_LOG_MESSAGE_MAX_SIZE]; + vsnprintf(msg, CUBEB_LOG_MESSAGE_MAX_SIZE, fmt, args); + va_end(args); + g_cubeb_log_callback.load()("%s:%d:%s", file, line, msg); +} + +void +cubeb_log_internal_no_format(const char * msg) +{ + g_cubeb_log_callback.load()(msg); +} + +void +cubeb_async_log(char const * fmt, ...) +{ + // This is going to copy a 256 bytes array around, which is fine. + // We don't want to allocate memory here, because this is made to + // be called from a real-time callback. + va_list args; + va_start(args, fmt); + char msg[CUBEB_LOG_MESSAGE_MAX_SIZE]; + vsnprintf(msg, CUBEB_LOG_MESSAGE_MAX_SIZE, fmt, args); + cubeb_async_logger::get().push(msg); + va_end(args); +} + +void +cubeb_async_log_reset_threads(void) +{ + if (!g_cubeb_log_callback) { + return; + } + cubeb_async_logger::get().reset_producer_thread(); +} + +void +cubeb_log_set(cubeb_log_level log_level, cubeb_log_callback log_callback) +{ + g_cubeb_log_level = log_level; + // Once a callback has a been set, `g_cubeb_log_callback` is never set back to + // nullptr, to prevent a TOCTOU race between checking the pointer + if (log_callback && log_level != CUBEB_LOG_DISABLED) { + g_cubeb_log_callback = log_callback; + cubeb_async_logger::get().start(); + } else if (!log_callback || CUBEB_LOG_DISABLED) { + g_cubeb_log_callback = cubeb_noop_log_callback; + // This returns once the thread has joined. + cubeb_async_logger::get().stop(); + } else { + assert(false && "Incorrect parameters passed to cubeb_log_set"); + } +} + +cubeb_log_level +cubeb_log_get_level() +{ + return g_cubeb_log_level; +} + +cubeb_log_callback +cubeb_log_get_callback() +{ + if (g_cubeb_log_callback == cubeb_noop_log_callback) { + return nullptr; + } + return g_cubeb_log_callback; +} -- cgit v1.2.3