From b88c91dd3d03f1a452cdd48f0db4e010cb150753 Mon Sep 17 00:00:00 2001
From: Yuri Kunde Schlesner <yuriks@yuriks.net>
Date: Tue, 12 May 2015 02:19:44 -0300
Subject: [PATCH 1/3] Common: Remove async logging
It provided a large increase in complexity of the logging system while
having a negligible performance impact: the usage patterns of the ring
buffer meant that each log contended with the logging thread, causing
it to effectively act as a synchronous extra buffering.
Also removed some broken code related to filtering of subclasses which
was broken since it was introduced. (Which means no one ever used that
feature anyway, since, 8 months later, no one ever complained.)
---
src/citra/citra.cpp | 6 --
src/citra_qt/main.cpp | 6 --
src/common/logging/backend.cpp | 56 +++-------------
src/common/logging/backend.h | 92 ++++-----------------------
src/common/logging/filter.cpp | 41 ++----------
src/common/logging/filter.h | 20 ++----
src/common/logging/log.h | 6 +-
src/common/logging/text_formatter.cpp | 19 +-----
src/common/logging/text_formatter.h | 8 ---
9 files changed, 32 insertions(+), 222 deletions(-)
diff --git a/src/citra/citra.cpp b/src/citra/citra.cpp
index 1d7e7f2700..ca93d5b91b 100644
--- a/src/citra/citra.cpp
+++ b/src/citra/citra.cpp
@@ -20,14 +20,8 @@
/// Application entry point
int main(int argc, char **argv) {
- std::shared_ptr<Log::Logger> logger = Log::InitGlobalLogger();
Log::Filter log_filter(Log::Level::Debug);
Log::SetFilter(&log_filter);
- std::thread logging_thread(Log::TextLoggingLoop, logger);
- SCOPE_EXIT({
- logger->Close();
- logging_thread.join();
- });
if (argc < 2) {
LOG_CRITICAL(Frontend, "Failed to load ROM: No ROM specified");
diff --git a/src/citra_qt/main.cpp b/src/citra_qt/main.cpp
index f115c5b6a6..bb7acf61b4 100644
--- a/src/citra_qt/main.cpp
+++ b/src/citra_qt/main.cpp
@@ -350,14 +350,8 @@ void GMainWindow::closeEvent(QCloseEvent* event)
int main(int argc, char* argv[])
{
- std::shared_ptr<Log::Logger> logger = Log::InitGlobalLogger();
Log::Filter log_filter(Log::Level::Info);
Log::SetFilter(&log_filter);
- std::thread logging_thread(Log::TextLoggingLoop, logger);
- SCOPE_EXIT({
- logger->Close();
- logging_thread.join();
- });
QApplication::setAttribute(Qt::AA_X11InitThreads);
QApplication app(argc, argv);
diff --git a/src/common/logging/backend.cpp b/src/common/logging/backend.cpp
index 7d3534a43d..bd2c6a1538 100644
--- a/src/common/logging/backend.cpp
+++ b/src/common/logging/backend.cpp
@@ -3,17 +3,17 @@
// Refer to the license.txt file included.
#include <algorithm>
+#include <array>
+#include <cstdio>
-#include "common/assert.h"
-
+#include "common/common_funcs.h" // snprintf compatibility define
#include "common/logging/backend.h"
+#include "common/logging/filter.h"
#include "common/logging/log.h"
#include "common/logging/text_formatter.h"
namespace Log {
-static std::shared_ptr<Logger> global_logger;
-
/// Macro listing all log classes. Code should define CLS and SUB as desired before invoking this.
#define ALL_LOG_CLASSES() \
CLS(Log) \
@@ -55,28 +55,8 @@ static std::shared_ptr<Logger> global_logger;
SUB(Render, OpenGL) \
CLS(Loader)
-Logger::Logger() {
- // Register logging classes so that they can be queried at runtime
- size_t parent_class;
- all_classes.reserve((size_t)Class::Count);
-
-#define CLS(x) \
- all_classes.push_back(Class::x); \
- parent_class = all_classes.size() - 1;
-#define SUB(x, y) \
- all_classes.push_back(Class::x##_##y); \
- all_classes[parent_class].num_children += 1;
-
- ALL_LOG_CLASSES()
-#undef CLS
-#undef SUB
-
- // Ensures that ALL_LOG_CLASSES isn't missing any entries.
- DEBUG_ASSERT(all_classes.size() == (size_t)Class::Count);
-}
-
// GetClassName is a macro defined by Windows.h, grrr...
-const char* Logger::GetLogClassName(Class log_class) {
+const char* GetLogClassName(Class log_class) {
switch (log_class) {
#define CLS(x) case Class::x: return #x;
#define SUB(x, y) case Class::x##_##y: return #x "." #y;
@@ -87,7 +67,7 @@ const char* Logger::GetLogClassName(Class log_class) {
return "Unknown";
}
-const char* Logger::GetLevelName(Level log_level) {
+const char* GetLevelName(Level log_level) {
#define LVL(x) case Level::x: return #x
switch (log_level) {
LVL(Trace);
@@ -101,19 +81,6 @@ const char* Logger::GetLevelName(Level log_level) {
#undef LVL
}
-void Logger::LogMessage(Entry entry) {
- ring_buffer.Push(std::move(entry));
-}
-
-size_t Logger::GetEntries(Entry* out_buffer, size_t buffer_len) {
- return ring_buffer.BlockingPop(out_buffer, buffer_len);
-}
-
-std::shared_ptr<Logger> InitGlobalLogger() {
- global_logger = std::make_shared<Logger>();
- return global_logger;
-}
-
Entry CreateEntry(Class log_class, Level log_level,
const char* filename, unsigned int line_nr, const char* function,
const char* format, va_list args) {
@@ -138,7 +105,7 @@ Entry CreateEntry(Class log_class, Level log_level,
return std::move(entry);
}
-static Filter* filter;
+static Filter* filter = nullptr;
void SetFilter(Filter* new_filter) {
filter = new_filter;
@@ -147,7 +114,7 @@ void SetFilter(Filter* new_filter) {
void LogMessage(Class log_class, Level log_level,
const char* filename, unsigned int line_nr, const char* function,
const char* format, ...) {
- if (!filter->CheckMessage(log_class, log_level))
+ if (filter != nullptr && !filter->CheckMessage(log_class, log_level))
return;
va_list args;
@@ -156,12 +123,7 @@ void LogMessage(Class log_class, Level log_level,
filename, line_nr, function, format, args);
va_end(args);
- if (global_logger != nullptr && !global_logger->IsClosed()) {
- global_logger->LogMessage(std::move(entry));
- } else {
- // Fall back to directly printing to stderr
- PrintMessage(entry);
- }
+ PrintColoredMessage(entry);
}
}
diff --git a/src/common/logging/backend.h b/src/common/logging/backend.h
index 3114f864cd..c1f4d08e46 100644
--- a/src/common/logging/backend.h
+++ b/src/common/logging/backend.h
@@ -4,17 +4,17 @@
#pragma once
+#include <chrono>
#include <cstdarg>
-#include <memory>
-#include <vector>
+#include <string>
+#include <utility>
-#include "common/concurrent_ring_buffer.h"
-
-#include "common/logging/filter.h"
#include "common/logging/log.h"
namespace Log {
+class Filter;
+
/**
* A log entry. Log entries are store in a structured format to permit more varied output
* formatting on different frontends, as well as facilitating filtering and aggregation.
@@ -48,89 +48,21 @@ struct Entry {
}
};
-struct ClassInfo {
- Class log_class;
-
- /**
- * Total number of (direct or indirect) sub classes this class has. If any, they follow in
- * sequence after this class in the class list.
- */
- unsigned int num_children = 0;
-
- ClassInfo(Class log_class) : log_class(log_class) {}
-};
+/**
+ * Returns the name of the passed log class as a C-string. Subclasses are separated by periods
+ * instead of underscores as in the enumeration.
+ */
+const char* GetLogClassName(Class log_class);
/**
- * Logging management class. This class has the dual purpose of acting as an exchange point between
- * the logging clients and the log outputter, as well as containing reflection info about available
- * log classes.
+ * Returns the name of the passed log level as a C-string.
*/
-class Logger {
-private:
- using Buffer = Common::ConcurrentRingBuffer<Entry, 16 * 1024 / sizeof(Entry)>;
-
-public:
- static const size_t QUEUE_CLOSED = Buffer::QUEUE_CLOSED;
-
- Logger();
-
- /**
- * Returns a list of all vector classes and subclasses. The sequence returned is a pre-order of
- * classes and subclasses, which together with the `num_children` field in ClassInfo, allows
- * you to recover the hierarchy.
- */
- const std::vector<ClassInfo>& GetClasses() const { return all_classes; }
-
- /**
- * Returns the name of the passed log class as a C-string. Subclasses are separated by periods
- * instead of underscores as in the enumeration.
- */
- static const char* GetLogClassName(Class log_class);
-
- /**
- * Returns the name of the passed log level as a C-string.
- */
- static const char* GetLevelName(Level log_level);
-
- /**
- * Appends a messages to the log buffer.
- * @note This function is thread safe.
- */
- void LogMessage(Entry entry);
-
- /**
- * Retrieves a batch of messages from the log buffer, blocking until they are available.
- * @note This function is thread safe.
- *
- * @param out_buffer Destination buffer that will receive the log entries.
- * @param buffer_len The maximum size of `out_buffer`.
- * @return The number of entries stored. In case the logger is shutting down, `QUEUE_CLOSED` is
- * returned, no entries are stored and the logger should shutdown.
- */
- size_t GetEntries(Entry* out_buffer, size_t buffer_len);
-
- /**
- * Initiates a shutdown of the logger. This will indicate to log output clients that they
- * should shutdown.
- */
- void Close() { ring_buffer.Close(); }
-
- /**
- * Returns true if Close() has already been called on the Logger.
- */
- bool IsClosed() const { return ring_buffer.IsClosed(); }
-
-private:
- Buffer ring_buffer;
- std::vector<ClassInfo> all_classes;
-};
+const char* GetLevelName(Level log_level);
/// Creates a log entry by formatting the given source location, and message.
Entry CreateEntry(Class log_class, Level log_level,
const char* filename, unsigned int line_nr, const char* function,
const char* format, va_list args);
-/// Initializes the default Logger.
-std::shared_ptr<Logger> InitGlobalLogger();
void SetFilter(Filter* filter);
diff --git a/src/common/logging/filter.cpp b/src/common/logging/filter.cpp
index 50f2e13f47..55cc8888a4 100644
--- a/src/common/logging/filter.cpp
+++ b/src/common/logging/filter.cpp
@@ -22,16 +22,6 @@ void Filter::SetClassLevel(Class log_class, Level level) {
class_levels[static_cast<size_t>(log_class)] = level;
}
-void Filter::SetSubclassesLevel(const ClassInfo& log_class, Level level) {
- const size_t log_class_i = static_cast<size_t>(log_class.log_class);
-
- const size_t begin = log_class_i + 1;
- const size_t end = begin + log_class.num_children;
- for (size_t i = begin; begin < end; ++i) {
- class_levels[i] = level;
- }
-}
-
void Filter::ParseFilterString(const std::string& filter_str) {
auto clause_begin = filter_str.cbegin();
while (clause_begin != filter_str.cend()) {
@@ -53,7 +43,7 @@ void Filter::ParseFilterString(const std::string& filter_str) {
template <typename It>
static Level GetLevelByName(const It begin, const It end) {
for (u8 i = 0; i < static_cast<u8>(Level::Count); ++i) {
- const char* level_name = Logger::GetLevelName(static_cast<Level>(i));
+ const char* level_name = GetLevelName(static_cast<Level>(i));
if (Common::ComparePartialString(begin, end, level_name)) {
return static_cast<Level>(i);
}
@@ -64,7 +54,7 @@ static Level GetLevelByName(const It begin, const It end) {
template <typename It>
static Class GetClassByName(const It begin, const It end) {
for (ClassType i = 0; i < static_cast<ClassType>(Class::Count); ++i) {
- const char* level_name = Logger::GetLogClassName(static_cast<Class>(i));
+ const char* level_name = GetLogClassName(static_cast<Class>(i));
if (Common::ComparePartialString(begin, end, level_name)) {
return static_cast<Class>(i);
}
@@ -72,20 +62,6 @@ static Class GetClassByName(const It begin, const It end) {
return Class::Count;
}
-template <typename InputIt, typename T>
-static InputIt find_last(InputIt begin, const InputIt end, const T& value) {
- auto match = end;
- while (begin != end) {
- auto new_match = std::find(begin, end, value);
- if (new_match != end) {
- match = new_match;
- ++new_match;
- }
- begin = new_match;
- }
- return match;
-}
-
bool Filter::ParseFilterRule(const std::string::const_iterator begin,
const std::string::const_iterator end) {
auto level_separator = std::find(begin, end, ':');
@@ -106,22 +82,13 @@ bool Filter::ParseFilterRule(const std::string::const_iterator begin,
return true;
}
- auto class_name_end = find_last(begin, level_separator, '.');
- if (class_name_end != level_separator &&
- !Common::ComparePartialString(class_name_end + 1, level_separator, "*")) {
- class_name_end = level_separator;
- }
-
- const Class log_class = GetClassByName(begin, class_name_end);
+ const Class log_class = GetClassByName(begin, level_separator);
if (log_class == Class::Count) {
LOG_ERROR(Log, "Unknown log class in filter: %s", std::string(begin, end).c_str());
return false;
}
- if (class_name_end == level_separator) {
- SetClassLevel(log_class, level);
- }
- SetSubclassesLevel(log_class, level);
+ SetClassLevel(log_class, level);
return true;
}
diff --git a/src/common/logging/filter.h b/src/common/logging/filter.h
index b53e4e6334..0b71ea3b21 100644
--- a/src/common/logging/filter.h
+++ b/src/common/logging/filter.h
@@ -11,8 +11,6 @@
namespace Log {
-struct ClassInfo;
-
/**
* Implements a log message filter which allows different log classes to have different minimum
* severity levels. The filter can be changed at runtime and can be parsed from a string to allow
@@ -27,29 +25,19 @@ public:
void ResetAll(Level level);
/// Sets the minimum level of `log_class` (and not of its subclasses) to `level`.
void SetClassLevel(Class log_class, Level level);
- /**
- * Sets the minimum level of all of `log_class` subclasses to `level`. The level of `log_class`
- * itself is not changed.
- */
- void SetSubclassesLevel(const ClassInfo& log_class, Level level);
/**
* Parses a filter string and applies it to this filter.
*
* A filter string consists of a space-separated list of filter rules, each of the format
* `<class>:<level>`. `<class>` is a log class name, with subclasses separated using periods.
- * A rule for a given class also affects all of its subclasses. `*` wildcards are allowed and
- * can be used to apply a rule to all classes or to all subclasses of a class without affecting
- * the parent class. `<level>` a severity level name which will be set as the minimum logging
- * level of the matched classes. Rules are applied left to right, with each rule overriding
- * previous ones in the sequence.
+ * `*` is allowed as a class name and will reset all filters to the specified level. `<level>`
+ * a severity level name which will be set as the minimum logging level of the matched classes.
+ * Rules are applied left to right, with each rule overriding previous ones in the sequence.
*
* A few examples of filter rules:
* - `*:Info` -- Resets the level of all classes to Info.
- * - `Service:Info` -- Sets the level of Service and all subclasses (Service.FS, Service.APT,
- * etc.) to Info.
- * - `Service.*:Debug` -- Sets the level of all Service subclasses to Debug, while leaving the
- * level of Service unchanged.
+ * - `Service:Info` -- Sets the level of Service to Info.
* - `Service.FS:Trace` -- Sets the level of the Service.FS class to Trace.
*/
void ParseFilterString(const std::string& filter_str);
diff --git a/src/common/logging/log.h b/src/common/logging/log.h
index 123641cb42..fd87ddbe61 100644
--- a/src/common/logging/log.h
+++ b/src/common/logging/log.h
@@ -78,11 +78,7 @@ enum class Class : ClassType {
Count ///< Total number of logging classes
};
-/**
- * Logs a message to the global logger. This proxy exists to avoid exposing the details of the
- * Logger class, including the ConcurrentRingBuffer template, to all files that desire to log
- * messages, reducing unecessary recompilations.
- */
+/// Logs a message to the global logger.
void LogMessage(Class log_class, Level log_level,
const char* filename, unsigned int line_nr, const char* function,
#ifdef _MSC_VER
diff --git a/src/common/logging/text_formatter.cpp b/src/common/logging/text_formatter.cpp
index 45be6d0a1b..94f3dfc1fc 100644
--- a/src/common/logging/text_formatter.cpp
+++ b/src/common/logging/text_formatter.cpp
@@ -46,8 +46,8 @@ void FormatLogMessage(const Entry& entry, char* out_text, size_t text_len) {
unsigned int time_seconds = static_cast<unsigned int>(entry.timestamp.count() / 1000000);
unsigned int time_fractional = static_cast<unsigned int>(entry.timestamp.count() % 1000000);
- const char* class_name = Logger::GetLogClassName(entry.log_class);
- const char* level_name = Logger::GetLevelName(entry.log_level);
+ const char* class_name = GetLogClassName(entry.log_class);
+ const char* level_name = GetLevelName(entry.log_level);
snprintf(out_text, text_len, "[%4u.%06u] %s <%s> %s: %s",
time_seconds, time_fractional, class_name, level_name,
@@ -116,19 +116,4 @@ void PrintColoredMessage(const Entry& entry) {
#endif
}
-void TextLoggingLoop(std::shared_ptr<Logger> logger) {
- std::array<Entry, 256> entry_buffer;
-
- while (true) {
- size_t num_entries = logger->GetEntries(entry_buffer.data(), entry_buffer.size());
- if (num_entries == Logger::QUEUE_CLOSED) {
- break;
- }
- for (size_t i = 0; i < num_entries; ++i) {
- const Entry& entry = entry_buffer[i];
- PrintColoredMessage(entry);
- }
- }
-}
-
}
diff --git a/src/common/logging/text_formatter.h b/src/common/logging/text_formatter.h
index 8474a19047..5b82f043fd 100644
--- a/src/common/logging/text_formatter.h
+++ b/src/common/logging/text_formatter.h
@@ -5,11 +5,9 @@
#pragma once
#include <cstddef>
-#include <memory>
namespace Log {
-class Logger;
struct Entry;
/**
@@ -31,10 +29,4 @@ void PrintMessage(const Entry& entry);
/// Prints the same message as `PrintMessage`, but colored acoording to the severity level.
void PrintColoredMessage(const Entry& entry);
-/**
- * Logging loop that repeatedly reads messages from the provided logger and prints them to the
- * console. It is the baseline barebones log outputter.
- */
-void TextLoggingLoop(std::shared_ptr<Logger> logger);
-
}
From c8eae338a8de614e175498408fcde8aa97736a54 Mon Sep 17 00:00:00 2001
From: Yuri Kunde Schlesner <yuriks@yuriks.net>
Date: Tue, 12 May 2015 02:52:31 -0300
Subject: [PATCH 2/3] Common: Use the log system to print assert messages
---
src/common/assert.h | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/src/common/assert.h b/src/common/assert.h
index 4f26c63e99..7b7d8bf28c 100644
--- a/src/common/assert.h
+++ b/src/common/assert.h
@@ -8,6 +8,7 @@
#include <cstdlib>
#include "common/common_funcs.h"
+#include "common/logging/log.h"
// For asserts we'd like to keep all the junk executed when an assert happens away from the
// important code in the function. One way of doing this is to put all the relevant code inside a
@@ -28,19 +29,14 @@ static void assert_noinline_call(const Fn& fn) {
exit(1); // Keeps GCC's mouth shut about this actually returning
}
-// TODO (yuriks) allow synchronous logging so we don't need printf
#define ASSERT(_a_) \
do if (!(_a_)) { assert_noinline_call([] { \
- fprintf(stderr, "Assertion Failed!\n\n Line: %d\n File: %s\n Time: %s\n", \
- __LINE__, __FILE__, __TIME__); \
+ LOG_CRITICAL(Debug, "Assertion Failed!"); \
}); } while (0)
#define ASSERT_MSG(_a_, ...) \
do if (!(_a_)) { assert_noinline_call([&] { \
- fprintf(stderr, "Assertion Failed!\n\n Line: %d\n File: %s\n Time: %s\n", \
- __LINE__, __FILE__, __TIME__); \
- fprintf(stderr, __VA_ARGS__); \
- fprintf(stderr, "\n"); \
+ LOG_CRITICAL(Debug, "Assertion Failed!\n" __VA_ARGS__); \
}); } while (0)
#define UNREACHABLE() ASSERT_MSG(false, "Unreachable code!")
From 7dbc27ff57d24a1c4e04e3f8cc35773ff9288516 Mon Sep 17 00:00:00 2001
From: Yuri Kunde Schlesner <yuriks@yuriks.net>
Date: Fri, 15 May 2015 23:57:53 -0300
Subject: [PATCH 3/3] Remove unused concurrent_ring_buffer.h
---
src/common/CMakeLists.txt | 1 -
src/common/concurrent_ring_buffer.h | 163 ----------------------------
2 files changed, 164 deletions(-)
delete mode 100644 src/common/concurrent_ring_buffer.h
diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index 11659c3c58..66e19d0e4a 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -28,7 +28,6 @@ set(HEADERS
common_funcs.h
common_paths.h
common_types.h
- concurrent_ring_buffer.h
cpu_detect.h
debug_interface.h
emu_window.h
diff --git a/src/common/concurrent_ring_buffer.h b/src/common/concurrent_ring_buffer.h
deleted file mode 100644
index c5889513a9..0000000000
--- a/src/common/concurrent_ring_buffer.h
+++ /dev/null
@@ -1,163 +0,0 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#pragma once
-
-#include <array>
-#include <condition_variable>
-#include <cstdint>
-#include <mutex>
-#include <thread>
-
-#include "common/common_types.h" // for NonCopyable
-
-namespace Common {
-
-/**
- * A MPMC (Multiple-Producer Multiple-Consumer) concurrent ring buffer. This data structure permits
- * multiple threads to push and pop from a queue of bounded size.
- */
-template <typename T, size_t ArraySize>
-class ConcurrentRingBuffer : private NonCopyable {
-public:
- /// Value returned by the popping functions when the queue has been closed.
- static const size_t QUEUE_CLOSED = -1;
-
- ConcurrentRingBuffer() {}
-
- ~ConcurrentRingBuffer() {
- // If for whatever reason the queue wasn't completely drained, destroy the left over items.
- for (size_t i = reader_index, end = writer_index; i != end; i = (i + 1) % ArraySize) {
- Data()[i].~T();
- }
- }
-
- /**
- * Pushes a value to the queue. If the queue is full, this method will block. Does nothing if
- * the queue is closed.
- */
- void Push(T val) {
- std::unique_lock<std::mutex> lock(mutex);
- if (closed) {
- return;
- }
-
- // If the buffer is full, wait
- writer.wait(lock, [&]{
- return (writer_index + 1) % ArraySize != reader_index;
- });
-
- T* item = &Data()[writer_index];
- new (item) T(std::move(val));
-
- writer_index = (writer_index + 1) % ArraySize;
-
- // Wake up waiting readers
- lock.unlock();
- reader.notify_one();
- }
-
- /**
- * Pops up to `dest_len` items from the queue, storing them in `dest`. This function will not
- * block, and might return 0 values if there are no elements in the queue when it is called.
- *
- * @return The number of elements stored in `dest`. If the queue has been closed, returns
- * `QUEUE_CLOSED`.
- */
- size_t Pop(T* dest, size_t dest_len) {
- std::unique_lock<std::mutex> lock(mutex);
- if (closed && !CanRead()) {
- return QUEUE_CLOSED;
- }
- return PopInternal(dest, dest_len);
- }
-
- /**
- * Pops up to `dest_len` items from the queue, storing them in `dest`. This function will block
- * if there are no elements in the queue when it is called.
- *
- * @return The number of elements stored in `dest`. If the queue has been closed, returns
- * `QUEUE_CLOSED`.
- */
- size_t BlockingPop(T* dest, size_t dest_len) {
- std::unique_lock<std::mutex> lock(mutex);
- if (closed && !CanRead()) {
- return QUEUE_CLOSED;
- }
-
- while (!CanRead()) {
- reader.wait(lock);
- if (closed && !CanRead()) {
- return QUEUE_CLOSED;
- }
- }
- DEBUG_ASSERT(CanRead());
- return PopInternal(dest, dest_len);
- }
-
- /**
- * Closes the queue. After calling this method, `Push` operations won't have any effect, and
- * `PopMany` and `PopManyBlock` will start returning `QUEUE_CLOSED`. This is intended to allow
- * a graceful shutdown of all consumers.
- */
- void Close() {
- std::unique_lock<std::mutex> lock(mutex);
- closed = true;
- // We need to wake up any reader that are waiting for an item that will never come.
- lock.unlock();
- reader.notify_all();
- }
-
- /// Returns true if `Close()` has been called.
- bool IsClosed() const {
- return closed;
- }
-
-private:
- size_t PopInternal(T* dest, size_t dest_len) {
- size_t output_count = 0;
- while (output_count < dest_len && CanRead()) {
- DEBUG_ASSERT(CanRead());
-
- T* item = &Data()[reader_index];
- T out_val = std::move(*item);
- item->~T();
-
- size_t prev_index = (reader_index + ArraySize - 1) % ArraySize;
- reader_index = (reader_index + 1) % ArraySize;
- if (writer_index == prev_index) {
- writer.notify_one();
- }
- dest[output_count++] = std::move(out_val);
- }
- return output_count;
- }
-
- bool CanRead() const {
- return reader_index != writer_index;
- }
-
- T* Data() {
- return static_cast<T*>(static_cast<void*>(&storage));
- }
-
- /// Storage for entries
- typename std::aligned_storage<ArraySize * sizeof(T),
- std::alignment_of<T>::value>::type storage;
-
- /// Data is valid in the half-open interval [reader, writer). If they are `QUEUE_CLOSED` then the
- /// queue has been closed.
- size_t writer_index = 0, reader_index = 0;
- // True if the queue has been closed.
- bool closed = false;
-
- /// Mutex that protects the entire data structure.
- std::mutex mutex;
- /// Signaling wakes up reader which is waiting for storage to be non-empty.
- std::condition_variable reader;
- /// Signaling wakes up writer which is waiting for storage to be non-full.
- std::condition_variable writer;
-};
-
-} // namespace