Use std::string_view in logging code

src/log.cpp

@@ -55,7 +55,7 @@ public:
 		return m_logger.hasOutput(m_level);
 	}
 
-	virtual void log(const std::string &buf) override {
+	virtual void log(std::string_view buf) override {
 		if (!m_raw) {
 			m_logger.log(m_level, buf);
 		} else {
@@ -106,7 +106,7 @@ thread_local LogStream dout_con(trace_target);
 // Android
 #ifdef __ANDROID__
 
-static unsigned int g_level_to_android[] = {
+constexpr static unsigned int g_level_to_android[] = {
 	ANDROID_LOG_INFO,     // LL_NONE
 	ANDROID_LOG_ERROR,    // LL_ERROR
 	ANDROID_LOG_WARN,     // LL_WARNING
@@ -116,11 +116,12 @@ static unsigned int g_level_to_android[] = {
 	ANDROID_LOG_VERBOSE,  // LL_TRACE
 };
 
-void AndroidLogOutput::logRaw(LogLevel lev, const std::string &line)
+void AndroidLogOutput::logRaw(LogLevel lev, std::string_view line)
 {
 	static_assert(ARRLEN(g_level_to_android) == LL_MAX,
 		"mismatch between android and internal loglevels");
-	__android_log_write(g_level_to_android[lev], PROJECT_NAME_C, line.c_str());
+	__android_log_print(g_level_to_android[lev], PROJECT_NAME_C, "%.*s",
+		line.size(), line.data());
 }
 #endif
 
@@ -131,7 +132,7 @@ void AndroidLogOutput::logRaw(LogLevel lev, const std::string &line)
 //// Logger
 ////
 
-LogLevel Logger::stringToLevel(const std::string &name)
+LogLevel Logger::stringToLevel(std::string_view name)
 {
 	if (name == "none")
 		return LL_NONE;
@@ -202,7 +203,7 @@ void Logger::setLevelSilenced(LogLevel lev, bool silenced)
 	m_silenced_levels[lev] = silenced;
 }
 
-void Logger::registerThread(const std::string &name)
+void Logger::registerThread(std::string_view name)
 {
 	std::thread::id id = std::this_thread::get_id();
 	MutexAutoLock lock(m_mutex);
@@ -252,7 +253,7 @@ const std::string &Logger::getThreadName()
 	return fallback_name;
 }
 
-void Logger::log(LogLevel lev, const std::string &text)
+void Logger::log(LogLevel lev, std::string_view text)
 {
 	if (isLevelSilenced(lev))
 		return;
@@ -268,7 +269,7 @@ void Logger::log(LogLevel lev, const std::string &text)
 	logToOutputs(lev, line, timestamp, thread_name, text);
 }
 
-void Logger::logRaw(LogLevel lev, const std::string &text)
+void Logger::logRaw(LogLevel lev, std::string_view text)
 {
 	if (isLevelSilenced(lev))
 		return;
@@ -276,7 +277,7 @@ void Logger::logRaw(LogLevel lev, const std::string &text)
 	logToOutputsRaw(lev, text);
 }
 
-void Logger::logToOutputsRaw(LogLevel lev, const std::string &line)
+void Logger::logToOutputsRaw(LogLevel lev, std::string_view line)
 {
 	MutexAutoLock lock(m_mutex);
 	for (size_t i = 0; i != m_outputs[lev].size(); i++)
@@ -285,7 +286,7 @@ void Logger::logToOutputsRaw(LogLevel lev, const std::string &line)
 
 void Logger::logToOutputs(LogLevel lev, const std::string &combined,
 	const std::string &time, const std::string &thread_name,
-	const std::string &payload_text)
+	std::string_view payload_text)
 {
 	MutexAutoLock lock(m_mutex);
 	for (size_t i = 0; i != m_outputs[lev].size(); i++)
@@ -334,7 +335,7 @@ StreamLogOutput::StreamLogOutput(std::ostream &stream) :
 #endif
 }
 
-void StreamLogOutput::logRaw(LogLevel lev, const std::string &line)
+void StreamLogOutput::logRaw(LogLevel lev, std::string_view line)
 {
 	bool colored_message = (Logger::color_mode == LOG_COLOR_ALWAYS) ||
 		(Logger::color_mode == LOG_COLOR_AUTO && is_tty);
@@ -385,7 +386,7 @@ void LogOutputBuffer::updateLogLevel()
 	m_logger.addOutputMaxLevel(this, log_level);
 }
 
-void LogOutputBuffer::logRaw(LogLevel lev, const std::string &line)
+void LogOutputBuffer::logRaw(LogLevel lev, std::string_view line)
 {
 	std::string color;
 

src/log.h

@@ -22,7 +22,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <atomic>
 #include <map>
 #include <queue>
-#include <string>
+#include <string_view>
 #include <fstream>
 #include <thread>
 #include <mutex>
@@ -62,14 +62,14 @@ public:
 	LogLevelMask removeOutput(ILogOutput *out);
 	void setLevelSilenced(LogLevel lev, bool silenced);
 
-	void registerThread(const std::string &name);
+	void registerThread(std::string_view name);
 	void deregisterThread();
 
-	void log(LogLevel lev, const std::string &text);
+	void log(LogLevel lev, std::string_view text);
 	// Logs without a prefix
-	void logRaw(LogLevel lev, const std::string &text);
+	void logRaw(LogLevel lev, std::string_view text);
 
-	static LogLevel stringToLevel(const std::string &name);
+	static LogLevel stringToLevel(std::string_view name);
 	static const char *getLevelLabel(LogLevel lev);
 
 	bool hasOutput(LogLevel level) {
@@ -83,10 +83,10 @@ public:
 	static LogColor color_mode;
 
 private:
-	void logToOutputsRaw(LogLevel, const std::string &line);
+	void logToOutputsRaw(LogLevel, std::string_view line);
 	void logToOutputs(LogLevel, const std::string &combined,
 		const std::string &time, const std::string &thread_name,
-		const std::string &payload_text);
+		std::string_view payload_text);
 
 	const std::string &getThreadName();
 
@@ -99,17 +99,17 @@ private:
 
 class ILogOutput {
 public:
-	virtual void logRaw(LogLevel, const std::string &line) = 0;
+	virtual void logRaw(LogLevel, std::string_view 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;
+		std::string_view 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)
+		std::string_view payload_text)
 	{
 		logRaw(lev, combined);
 	}
@@ -119,7 +119,7 @@ class StreamLogOutput : public ICombinedLogOutput {
 public:
 	StreamLogOutput(std::ostream &stream);
 
-	void logRaw(LogLevel lev, const std::string &line);
+	void logRaw(LogLevel lev, std::string_view line);
 
 private:
 	std::ostream &m_stream;
@@ -130,7 +130,7 @@ class FileLogOutput : public ICombinedLogOutput {
 public:
 	void setFile(const std::string &filename, s64 file_size_max);
 
-	void logRaw(LogLevel lev, const std::string &line)
+	void logRaw(LogLevel lev, std::string_view line)
 	{
 		m_stream << line << std::endl;
 	}
@@ -154,7 +154,7 @@ public:
 
 	void updateLogLevel();
 
-	void logRaw(LogLevel lev, const std::string &line);
+	void logRaw(LogLevel lev, std::string_view line);
 
 	void clear()
 	{
@@ -190,7 +190,7 @@ private:
 #ifdef __ANDROID__
 class AndroidLogOutput : public ICombinedLogOutput {
 public:
-	void logRaw(LogLevel lev, const std::string &line);
+	void logRaw(LogLevel lev, std::string_view line);
 };
 #endif
 
@@ -206,7 +206,7 @@ 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;
+	virtual void log(std::string_view buf) = 0;
 };
 
 
@@ -304,7 +304,7 @@ public:
 		return m_target.hasOutput();
 	}
 
-	void internalFlush(const std::string &buf) {
+	void internalFlush(std::string_view buf) {
 		m_target.log(buf);
 	}
 

src/script/common/c_internal.cpp

@@ -122,27 +122,30 @@ void script_error(lua_State *L, int pcall_result, const char *mod, const char *f
 	throw LuaError(err_msg);
 }
 
-static void script_log_add_source(lua_State *L, std::string &message, int stack_depth)
+[[nodiscard]] static std::string script_log_add_source(lua_State *L,
+	std::string_view message, int stack_depth)
 {
+	std::string ret(message);
 	if (stack_depth <= 0)
-		return;
+		return ret;
 
 	lua_Debug ar;
 	if (lua_getstack(L, stack_depth, &ar)) {
 		FATAL_ERROR_IF(!lua_getinfo(L, "Sl", &ar), "lua_getinfo() failed");
-		message.append(" (at " + std::string(ar.short_src) + ":"
+		ret.append(" (at ").append(ar.short_src).append(":"
 			+ std::to_string(ar.currentline) + ")");
 	} else {
-		message.append(" (at ?:?)");
+		ret.append(" (at ?:?)");
 	}
+	return ret;
 }
 
-bool script_log_unique(lua_State *L, std::string message, std::ostream &log_to,
+bool script_log_unique(lua_State *L, std::string_view message_in, std::ostream &log_to,
 	int stack_depth)
 {
 	thread_local std::vector<u64> logged_messages;
 
-	script_log_add_source(L, message, stack_depth);
+	auto message = script_log_add_source(L, message_in, stack_depth);
 	u64 hash = murmur_hash_64_ua(message.data(), message.length(), 0xBADBABE);
 
 	if (std::find(logged_messages.begin(), logged_messages.end(), hash)
@@ -174,7 +177,7 @@ DeprecatedHandlingMode get_deprecated_handling_mode()
 	return ret;
 }
 
-void log_deprecated(lua_State *L, std::string message, int stack_depth, bool once)
+void log_deprecated(lua_State *L, std::string_view message, int stack_depth, bool once)
 {
 	DeprecatedHandlingMode mode = get_deprecated_handling_mode();
 	if (mode == DeprecatedHandlingMode::Ignore)
@@ -184,12 +187,12 @@ void log_deprecated(lua_State *L, std::string message, int stack_depth, bool onc
 	if (once) {
 		log = script_log_unique(L, message, warningstream, stack_depth);
 	} else {
-		script_log_add_source(L, message, stack_depth);
-		warningstream << message << std::endl;
+		auto message2 = script_log_add_source(L, message, stack_depth);
+		warningstream << message2 << std::endl;
 	}
 
 	if (mode == DeprecatedHandlingMode::Error)
-		throw LuaError(message);
+		throw LuaError(std::string(message));
 	else if (log)
 		infostream << script_get_backtrace(L) << std::endl;
 }

src/script/common/c_internal.h

@@ -26,6 +26,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #pragma once
 
+#include <string_view>
+
 extern "C" {
 #include <lua.h>
 #include <lauxlib.h>
@@ -127,7 +129,7 @@ int script_error_handler(lua_State *L);
 // Takes an error from lua_pcall and throws it as a LuaError
 void script_error(lua_State *L, int pcall_result, const char *mod, const char *fxn);
 
-bool script_log_unique(lua_State *L, std::string message, std::ostream &log_to,
+bool script_log_unique(lua_State *L, std::string_view message, std::ostream &log_to,
 	int stack_depth = 1);
 
 enum DeprecatedHandlingMode {
@@ -152,7 +154,8 @@ DeprecatedHandlingMode get_deprecated_handling_mode();
  *        (ie: not builtin or core). -1 to disabled.
  * @param once Log the deprecation warning only once per callsite.
  */
-void log_deprecated(lua_State *L, std::string message, int stack_depth = 1, bool once = false);
+void log_deprecated(lua_State *L, std::string_view message,
+	int stack_depth = 1, bool once = false);
 
 // Safely call string.dump on a function value
 // (does not pop, leaves one value on stack)

src/script/lua_api/l_util.cpp

@@ -61,13 +61,13 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 int ModApiUtil::l_log(lua_State *L)
 {
 	NO_MAP_LOCK_REQUIRED;
-	std::string text;
+	std::string_view text;
 	LogLevel level = LL_NONE;
-	if (lua_isnone(L, 2)) {
-		text = luaL_checkstring(L, 1);
+	if (lua_isnoneornil(L, 2)) {
+		text = readParam<std::string_view>(L, 1);
 	} else {
-		std::string name = luaL_checkstring(L, 1);
-		text = luaL_checkstring(L, 2);
+		auto name = readParam<std::string_view>(L, 1);
+		text = readParam<std::string_view>(L, 2);
 		if (name == "deprecated") {
 			log_deprecated(L, text, 2);
 			return 0;
@@ -75,7 +75,7 @@ int ModApiUtil::l_log(lua_State *L)
 		level = Logger::stringToLevel(name);
 		if (level == LL_MAX) {
 			warningstream << "Tried to log at unknown level '" << name
-				<< "'.  Defaulting to \"none\"." << std::endl;
+				<< "'. Defaulting to \"none\"." << std::endl;
 			level = LL_NONE;
 		}
 	}

src/terminal_chat_console.h

@@ -32,14 +32,14 @@ struct ChatInterface;
 class TermLogOutput : public ILogOutput {
 public:
 
-	void logRaw(LogLevel lev, const std::string &line)
+	void logRaw(LogLevel lev, std::string_view line)
 	{
-		queue.push_back(std::make_pair(lev, line));
+		queue.push_back(std::make_pair(lev, std::string(line)));
 	}
 
 	virtual void log(LogLevel lev, const std::string &combined,
 		const std::string &time, const std::string &thread_name,
-		const std::string &payload_text)
+		std::string_view payload_text)
 	{
 		std::ostringstream os(std::ios_base::binary);
 		os << time << ": [" << thread_name << "] " << payload_text;

src/util/stream.h

@@ -20,10 +20,10 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #pragma once
 
 #include <iostream>
-#include <string>
+#include <string_view>
 #include <functional>
 
-template<int BufferLength, typename Emitter = std::function<void(const std::string &)> >
+template<int BufferLength, typename Emitter = std::function<void(std::string_view)> >
 class StringStreamBuffer : public std::streambuf {
 public:
 	StringStreamBuffer(Emitter emitter) : m_emitter(emitter) {
@@ -38,19 +38,19 @@ public:
 	void push_back(char c) {
 		if (c == '\n' || c == '\r') {
 			if (buffer_index)
-				m_emitter(std::string(buffer, buffer_index));
+				m_emitter(std::string_view(buffer, buffer_index));
 			buffer_index = 0;
 		} else {
 			buffer[buffer_index++] = c;
 			if (buffer_index >= BufferLength) {
-				m_emitter(std::string(buffer, buffer_index));
+				m_emitter(std::string_view(buffer, buffer_index));
 				buffer_index = 0;
 			}
 		}
 	}
 
 	std::streamsize xsputn(const char *s, std::streamsize n) {
-		for (int i = 0; i < n; ++i)
+		for (std::streamsize i = 0; i < n; ++i)
 			push_back(s[i]);
 		return n;
 	}