From d79405cdb712a3dfeea480599c6defb9f22d11c3 Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fischer@muhq.space>
Date: Mon, 21 Feb 2022 19:29:39 +0100
Subject: [PATCH] generalize LogBuffer to MappedFileBuffer
---
.../MappedFileBuffer.cpp} | 46 +++++++++----------
emper/lib/MappedFileBuffer.hpp | 34 ++++++++++++++
emper/lib/meson.build | 1 +
emper/log/LogBuffer.hpp | 30 +++---------
emper/log/meson.build | 1 -
5 files changed, 64 insertions(+), 48 deletions(-)
rename emper/{log/LogBuffer.cpp => lib/MappedFileBuffer.cpp} (73%)
create mode 100644 emper/lib/MappedFileBuffer.hpp
diff --git a/emper/log/LogBuffer.cpp b/emper/lib/MappedFileBuffer.cpp
similarity index 73%
rename from emper/log/LogBuffer.cpp
rename to emper/lib/MappedFileBuffer.cpp
index 94bd3f7b..320e1253 100644
--- a/emper/log/LogBuffer.cpp
+++ b/emper/lib/MappedFileBuffer.cpp
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: LGPL-3.0-or-later
-// Copyright © 2020 Florian Schmaus
-#include "LogBuffer.hpp"
+// Copyright © 2021-2022 Florian Fischer
+#include "lib/MappedFileBuffer.hpp"
#include <fcntl.h>
#include <sys/mman.h>
@@ -12,17 +12,17 @@
#include "Common.hpp"
-namespace emper::log {
+namespace emper::lib {
-LogBuffer::LogBuffer(const std::string& logFile) : logFile(logFile) {
- logFd = open(logFile.c_str(), O_RDWR | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
- if (logFd == -1) {
- DIE_MSG_ERRNO("opening log file " << logFile << " failed");
+MappedFileBuffer::MappedFileBuffer(const std::string& file) : file(file) {
+ fd = open(file.c_str(), O_RDWR | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+ if (fd == -1) {
+ DIE_MSG_ERRNO("opening file " << file << " failed");
}
for (size_t i = 0; i < BUFFER_COUNT; ++i) {
const auto off = static_cast<off_t>(i * BUFFER_SIZE);
- void* res = mmap(nullptr, BUFFER_SIZE, PROT_WRITE, MAP_FILE | MAP_SHARED, logFd, off);
+ void* res = mmap(nullptr, BUFFER_SIZE, PROT_WRITE, MAP_FILE | MAP_SHARED, fd, off);
// NOLINTNEXTLINE(performance-no-int-to-ptr)
if (res == MAP_FAILED) {
DIE_MSG_ERRNO("mmap failed");
@@ -30,19 +30,19 @@ LogBuffer::LogBuffer(const std::string& logFile) : logFile(logFile) {
bufs[i] = static_cast<char*>(res);
}
- if (ftruncate(logFd, BUFFER_COUNT * BUFFER_SIZE)) {
- DIE_MSG_ERRNO("initial log file " << logFile << "truncation failed");
+ if (ftruncate(fd, BUFFER_COUNT * BUFFER_SIZE)) {
+ DIE_MSG_ERRNO("initial mapped file " << file << "truncation failed");
}
}
-void LogBuffer::trim() {
+void MappedFileBuffer::trim() {
const auto finalPos = static_cast<off_t>(bufPos.load(std::memory_order_relaxed));
- if (ftruncate(logFd, finalPos)) {
- DIE_MSG_ERRNO("trimming log file " << logFile << " failed");
+ if (ftruncate(fd, finalPos)) {
+ DIE_MSG_ERRNO("trimming mapped file " << file << " failed");
}
}
-LogBuffer::~LogBuffer() {
+MappedFileBuffer::~MappedFileBuffer() {
trim();
for (auto* buf : bufs) {
@@ -51,10 +51,10 @@ LogBuffer::~LogBuffer() {
}
}
- close(logFd);
+ close(fd);
}
-void LogBuffer::log(const std::string& message) {
+void MappedFileBuffer::put(const std::string& message) {
const size_t messageLen = message.size();
const size_t startPos = bufPos.fetch_add(messageLen, std::memory_order_relaxed);
const size_t endPos = startPos + messageLen - 1;
@@ -104,16 +104,16 @@ void LogBuffer::log(const std::string& message) {
// Therefore at bufPos = BUFFER_SIZE + 1 we are in the second active buffer
const size_t nthActive = (endPos / BUFFER_SIZE) + 1;
- // Our log file has the size of all ever active buffers plus the new fresh one
- const auto logFileSize = static_cast<off_t>((nthActive + 1) * BUFFER_SIZE);
+ // Our mapped file has the size of all ever active buffers plus the new fresh one
+ const auto fileSize = static_cast<off_t>((nthActive + 1) * BUFFER_SIZE);
- // Grow the log file
- if (ftruncate(logFd, logFileSize)) {
- DIE_MSG_ERRNO("growing log file " << logFile << " failed");
+ // Grow the mapped file
+ if (ftruncate(fd, fileSize)) {
+ DIE_MSG_ERRNO("growing mapped file " << file << " failed");
}
const auto nextOffset = static_cast<off_t>(nthActive * BUFFER_SIZE);
- void* res = mmap(nullptr, BUFFER_SIZE, PROT_WRITE, MAP_FILE | MAP_SHARED, logFd, nextOffset);
+ void* res = mmap(nullptr, BUFFER_SIZE, PROT_WRITE, MAP_FILE | MAP_SHARED, fd, nextOffset);
// NOLINTNEXTLINE(performance-no-int-to-ptr)
if (res == MAP_FAILED) {
DIE_MSG_ERRNO("mmap of fresh buffer failed");
@@ -125,4 +125,4 @@ void LogBuffer::log(const std::string& message) {
}
}
-} // namespace emper::log
+} // namespace emper::lib
diff --git a/emper/lib/MappedFileBuffer.hpp b/emper/lib/MappedFileBuffer.hpp
new file mode 100644
index 00000000..f267fa8d
--- /dev/null
+++ b/emper/lib/MappedFileBuffer.hpp
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright © 2021-2022 Florian Fischer
+#pragma once
+
+#include <atomic>
+#include <cstddef>
+#include <string>
+
+namespace emper::lib {
+class MappedFileBuffer {
+ // We use a triple buffer scheme, where one buffer is active, one is old and one is fresh
+ // The old buffer gets remapped by the first accessing the fresh buffer
+ static const int BUFFER_COUNT = 3;
+ // Use 1GB buffers to reduce the risk of using an unmapped one
+ static const size_t BUFFER_SIZE = 1 << 30;
+
+ char* bufs[BUFFER_COUNT];
+
+ std::atomic<size_t> bufPos = 0;
+
+ std::string file;
+ int fd;
+
+ auto getBuf(size_t pos) -> char* { return bufs[(pos / BUFFER_SIZE) % BUFFER_COUNT]; }
+
+ void trim();
+
+ public:
+ MappedFileBuffer(const std::string& file);
+ ~MappedFileBuffer();
+
+ void put(const std::string& message);
+};
+} // namespace emper::lib
diff --git a/emper/lib/meson.build b/emper/lib/meson.build
index 3aa7f195..16a4c6a5 100644
--- a/emper/lib/meson.build
+++ b/emper/lib/meson.build
@@ -2,6 +2,7 @@ emper_cpp_sources += files(
'DebugUtil.cpp',
'env.cpp',
'LinuxVersion.cpp',
+ 'MappedFileBuffer.cpp',
'util.cpp',
)
diff --git a/emper/log/LogBuffer.hpp b/emper/log/LogBuffer.hpp
index f4149ee9..ea20674f 100644
--- a/emper/log/LogBuffer.hpp
+++ b/emper/log/LogBuffer.hpp
@@ -1,34 +1,16 @@
// SPDX-License-Identifier: LGPL-3.0-or-later
-// Copyright © 2021 Florian Fischer
+// Copyright © 2021-2022 Florian Fischer
#pragma once
-#include <atomic>
-#include <cstddef>
#include <string>
-namespace emper::log {
-class LogBuffer {
- // We use a triple buffer scheme, where one buffer is active, one is old and one is fresh
- // The old buffer gets remapped by the first accessing the fresh buffer
- static const int BUFFER_COUNT = 3;
- // Use 1GB buffers to reduce the risk of using an unmapped one
- static const size_t BUFFER_SIZE = 1 << 30;
-
- char* bufs[BUFFER_COUNT];
-
- std::atomic<size_t> bufPos = 0;
-
- std::string logFile;
- int logFd;
-
- auto getBuf(size_t pos) -> char* { return bufs[(pos / BUFFER_SIZE) % BUFFER_COUNT]; }
-
- void trim();
+#include "lib/MappedFileBuffer.hpp"
+namespace emper::log {
+class LogBuffer : emper::lib::MappedFileBuffer {
public:
- LogBuffer(const std::string& logFile);
- ~LogBuffer();
+ LogBuffer(const std::string& logFile) : MappedFileBuffer(logFile) {}
- void log(const std::string& message);
+ void log(const std::string& message) { put(message); };
};
} // namespace emper::log
diff --git a/emper/log/meson.build b/emper/log/meson.build
index 6de1e134..cef2f999 100644
--- a/emper/log/meson.build
+++ b/emper/log/meson.build
@@ -1,4 +1,3 @@
emper_cpp_sources += files(
'log.cpp',
- 'LogBuffer.cpp',
)
--
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