Initial commit

src/log.h

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+/*
+Minetest
+Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#pragma once
+
+#include <atomic>
+#include <map>
+#include <queue>
+#include <string>
+#include <fstream>
+#include <thread>
+#include <mutex>
+#if !defined(_WIN32)  // POSIX
+	#include <unistd.h>
+#endif
+#include "threading/mutex_auto_lock.h"
+#include "util/basic_macros.h"
+#include "util/stream.h"
+#include "irrlichttypes.h"
+
+class ILogOutput;
+
+enum LogLevel {
+	LL_NONE, // Special level that is always printed
+	LL_ERROR,
+	LL_WARNING,
+	LL_ACTION,  // In-game actions
+	LL_INFO,
+	LL_VERBOSE,
+	LL_TRACE,
+	LL_MAX,
+};
+
+enum LogColor {
+	LOG_COLOR_NEVER,
+	LOG_COLOR_ALWAYS,
+	LOG_COLOR_AUTO,
+};
+
+typedef u8 LogLevelMask;
+#define LOGLEVEL_TO_MASKLEVEL(x) (1 << x)
+
+class Logger {
+public:
+	void addOutput(ILogOutput *out);
+	void addOutput(ILogOutput *out, LogLevel lev);
+	void addOutputMasked(ILogOutput *out, LogLevelMask mask);
+	void addOutputMaxLevel(ILogOutput *out, LogLevel lev);
+	LogLevelMask removeOutput(ILogOutput *out);
+	void setLevelSilenced(LogLevel lev, bool silenced);
+
+	void registerThread(const std::string &name);
+	void deregisterThread();
+
+	void log(LogLevel lev, const std::string &text);
+	// Logs without a prefix
+	void logRaw(LogLevel lev, const std::string &text);
+
+	static LogLevel stringToLevel(const std::string &name);
+	static const std::string getLevelLabel(LogLevel lev);
+
+	bool hasOutput(LogLevel level) {
+		return m_has_outputs[level].load(std::memory_order_relaxed);
+	}
+
+	static LogColor color_mode;
+
+private:
+	void logToOutputsRaw(LogLevel, const std::string &line);
+	void logToOutputs(LogLevel, const std::string &combined,
+		const std::string &time, const std::string &thread_name,
+		const std::string &payload_text);
+
+	const std::string getThreadName();
+
+	std::vector<ILogOutput *> m_outputs[LL_MAX];
+	std::atomic<bool> m_has_outputs[LL_MAX];
+
+	// Should implement atomic loads and stores (even though it's only
+	// written to when one thread has access currently).
+	// Works on all known architectures (x86, ARM, MIPS).
+	volatile bool m_silenced_levels[LL_MAX];
+	std::map<std::thread::id, std::string> m_thread_names;
+	mutable std::mutex m_mutex;
+};
+
+class ILogOutput {
+public:
+	virtual void logRaw(LogLevel, const std::string &line) = 0;
+	virtual void log(LogLevel, const std::string &combined,
+		const std::string &time, const std::string &thread_name,
+		const std::string &payload_text) = 0;
+};
+
+class ICombinedLogOutput : public ILogOutput {
+public:
+	void log(LogLevel lev, const std::string &combined,
+		const std::string &time, const std::string &thread_name,
+		const std::string &payload_text)
+	{
+		logRaw(lev, combined);
+	}
+};
+
+class StreamLogOutput : public ICombinedLogOutput {
+public:
+	StreamLogOutput(std::ostream &stream) :
+		m_stream(stream)
+	{
+#if !defined(_WIN32)
+		is_tty = isatty(fileno(stdout));
+#else
+		is_tty = false;
+#endif
+	}
+
+	void logRaw(LogLevel lev, const std::string &line);
+
+private:
+	std::ostream &m_stream;
+	bool is_tty;
+};
+
+class FileLogOutput : public ICombinedLogOutput {
+public:
+	void setFile(const std::string &filename, s64 file_size_max);
+
+	void logRaw(LogLevel lev, const std::string &line)
+	{
+		m_stream << line << std::endl;
+	}
+
+private:
+	std::ofstream m_stream;
+};
+
+class LogOutputBuffer : public ICombinedLogOutput {
+public:
+	LogOutputBuffer(Logger &logger) :
+		m_logger(logger)
+	{
+		updateLogLevel();
+	};
+
+	virtual ~LogOutputBuffer()
+	{
+		m_logger.removeOutput(this);
+	}
+
+	void updateLogLevel();
+
+	void logRaw(LogLevel lev, const std::string &line);
+
+	void clear()
+	{
+		MutexAutoLock lock(m_buffer_mutex);
+		m_buffer = std::queue<std::string>();
+	}
+
+	bool empty() const
+	{
+		MutexAutoLock lock(m_buffer_mutex);
+		return m_buffer.empty();
+	}
+
+	std::string get()
+	{
+		MutexAutoLock lock(m_buffer_mutex);
+		if (m_buffer.empty())
+			return "";
+		std::string s = std::move(m_buffer.front());
+		m_buffer.pop();
+		return s;
+	}
+
+private:
+	// g_logger serializes calls to logRaw() with a mutex, but that
+	// doesn't prevent get() / clear() from being called on top of it.
+	// This mutex prevents that.
+	mutable std::mutex m_buffer_mutex;
+	std::queue<std::string> m_buffer;
+	Logger &m_logger;
+};
+
+#ifdef __ANDROID__
+class AndroidLogOutput : public ICombinedLogOutput {
+public:
+	void logRaw(LogLevel lev, const std::string &line);
+};
+#endif
+
+/*
+ * LogTarget
+ *
+ * This is the interface that sits between the LogStreams and the global logger.
+ * Primarily used to route streams to log levels, but could also enable other
+ * custom behavior.
+ *
+ */
+class LogTarget {
+public:
+	// Must be thread-safe. These can be called from any thread.
+	virtual bool hasOutput() = 0;
+	virtual void log(const std::string &buf) = 0;
+};
+
+
+/*
+ * StreamProxy
+ *
+ * An ostream-like object that can proxy to a real ostream or do nothing,
+ * depending on how it is configured. See LogStream below.
+ *
+ */
+class StreamProxy {
+public:
+	StreamProxy(std::ostream *os) : m_os(os) { }
+
+	template<typename T>
+	StreamProxy& operator<<(T&& arg) {
+		if (m_os) {
+			*m_os << std::forward<T>(arg);
+		}
+		return *this;
+	}
+
+	StreamProxy& operator<<(std::ostream& (*manip)(std::ostream&)) {
+		if (m_os) {
+			*m_os << manip;
+		}
+		return *this;
+	}
+
+private:
+	std::ostream *m_os;
+};
+
+
+/*
+ * LogStream
+ *
+ * The public interface for log streams (infostream, verbosestream, etc).
+ *
+ * LogStream minimizes the work done when a given stream is off. (meaning
+ * it has no output targets, so it goes to /dev/null)
+ *
+ * For example, consider:
+ *
+ *     verbosestream << "hello world" << 123 << std::endl;
+ *
+ * The compiler evaluates this as:
+ *
+ *   (((verbosestream << "hello world") << 123) << std::endl)
+ *      ^                            ^
+ *
+ * If `verbosestream` is on, the innermost expression (marked by ^) will return
+ * a StreamProxy that forwards to a real ostream, that feeds into the logger.
+ * However, if `verbosestream` is off, it will return a StreamProxy that does
+ * nothing on all later operations. Specifically, CPU time won't be wasted
+ * writing "hello world" and 123 into a buffer, or formatting the log entry.
+ *
+ * It is also possible to directly check if the stream is on/off:
+ *
+ *   if (verbosestream) {
+ *       auto data = ComputeExpensiveDataForTheLog();
+ *       verbosestream << data << endl;
+ *   }
+ *
+*/
+
+class LogStream {
+public:
+	LogStream() = delete;
+	DISABLE_CLASS_COPY(LogStream);
+
+	LogStream(LogTarget &target) :
+		m_target(target),
+		m_buffer(std::bind(&LogStream::internalFlush, this, std::placeholders::_1)),
+		m_dummy_buffer(),
+		m_stream(&m_buffer),
+		m_dummy_stream(&m_dummy_buffer),
+		m_proxy(&m_stream),
+		m_dummy_proxy(nullptr) { }
+
+	template<typename T>
+	StreamProxy& operator<<(T&& arg) {
+		StreamProxy& sp = m_target.hasOutput() ? m_proxy : m_dummy_proxy;
+		sp << std::forward<T>(arg);
+		return sp;
+	}
+
+	StreamProxy& operator<<(std::ostream& (*manip)(std::ostream&)) {
+		StreamProxy& sp = m_target.hasOutput() ? m_proxy : m_dummy_proxy;
+		sp << manip;
+		return sp;
+	}
+
+	operator bool() {
+		return m_target.hasOutput();
+	}
+
+	void internalFlush(const std::string &buf) {
+		m_target.log(buf);
+	}
+
+	operator std::ostream&() {
+		return m_target.hasOutput() ? m_stream : m_dummy_stream;
+	}
+
+private:
+	// 10 streams per thread x (256 + overhead) ~ 3K per thread
+	static const int BUFFER_LENGTH = 256;
+	LogTarget &m_target;
+	StringStreamBuffer<BUFFER_LENGTH> m_buffer;
+	DummyStreamBuffer m_dummy_buffer;
+	std::ostream m_stream;
+	std::ostream m_dummy_stream;
+	StreamProxy m_proxy;
+	StreamProxy m_dummy_proxy;
+
+};
+
+#ifdef __ANDROID__
+extern AndroidLogOutput stdout_output;
+extern AndroidLogOutput stderr_output;
+#else
+extern StreamLogOutput stdout_output;
+extern StreamLogOutput stderr_output;
+#endif
+
+extern Logger g_logger;
+
+/*
+ * By making the streams thread_local, each thread has its own
+ * private buffer. Two or more threads can write to the same stream
+ * simultaneously (lock-free), and there won't be any interference.
+ *
+ * The finished lines are sent to a LogTarget which is a global (not thread-local)
+ * object, and from there relayed to g_logger. The final writes are serialized
+ * by the mutex in g_logger.
+*/
+
+extern thread_local LogStream dstream;
+extern thread_local LogStream rawstream;  // Writes directly to all LL_NONE log outputs with no prefix.
+extern thread_local LogStream errorstream;
+extern thread_local LogStream warningstream;
+extern thread_local LogStream actionstream;
+extern thread_local LogStream infostream;
+extern thread_local LogStream verbosestream;
+extern thread_local LogStream tracestream;
+// TODO: Search/replace these with verbose/tracestream
+extern thread_local LogStream derr_con;
+extern thread_local LogStream dout_con;
+
+#define TRACESTREAM(x) do {	\
+	if (tracestream) { 	\
+		tracestream x;	\
+	}			\
+} while (0)