system/FmtError: new library

Replaces the Format*() functions in system/Error.hxx.

src/LogInit.cxx

@@ -21,6 +21,7 @@
 #include "LogInit.hxx"
 #include "LogBackend.hxx"
 #include "Log.hxx"
+#include "lib/fmt/PathFormatter.hxx"
 #include "config/Param.hxx"
 #include "config/Data.hxx"
 #include "config/Option.hxx"
@@ -29,7 +30,7 @@
 #include "util/Domain.hxx"
 #include "util/RuntimeError.hxx"
 #include "util/StringAPI.hxx"
-#include "system/Error.hxx"
+#include "system/FmtError.hxx"
 
 #include <cassert>
 
@@ -82,10 +83,8 @@ log_init_file(int line)
 		throw FormatRuntimeError("failed to open log file \"%s\" (config line %d)",
 					 out_path_utf8.c_str(), line);
 #else
-		int e = errno;
+		throw FmtErrno("failed to open log file \"{}\" (config line {})",
-		const std::string out_path_utf8 = out_path.ToUTF8();
+			       out_path, line);
-		throw FormatErrno(e, "failed to open log file \"%s\" (config line %d)",
-				  out_path_utf8.c_str(), line);
 #endif
 	}
 
@@ -242,10 +241,9 @@ cycle_log_files() noexcept
 
 	fd = open_log_file();
 	if (fd < 0) {
-		const std::string out_path_utf8 = out_path.ToUTF8();
 		FmtError(log_domain,
 			 "error re-opening log file: {}",
-			 out_path_utf8);
+			 out_path);
 		return -1;
 	}
 

src/archive/plugins/ZzipArchivePlugin.cxx

@@ -136,8 +136,8 @@ ZzipArchiveFile::OpenStream(const char *pathname,
 		const auto error = (zzip_error_t)zzip_error(dir->dir);
 		switch (error) {
 		case ZZIP_ENOENT:
-			throw FormatFileNotFound("Failed to open '%s' in ZIP file",
+			throw FmtFileNotFound("Failed to open '{}' in ZIP file",
-						 pathname);
+					      pathname);
 
 		default:
 			throw FormatRuntimeError("Failed to open '%s' in ZIP file: %s",

src/config/File.cxx

@@ -22,6 +22,7 @@
 #include "Param.hxx"
 #include "Block.hxx"
 #include "Templates.hxx"
+#include "lib/fmt/PathFormatter.hxx"
 #include "system/Error.hxx"
 #include "util/Tokenizer.hxx"
 #include "util/StringStrip.hxx"
@@ -236,9 +237,8 @@ void
 ReadConfigFile(ConfigData &config_data, Path path)
 {
 	assert(!path.IsNull());
-	const std::string path_utf8 = path.ToUTF8();
 
-	FmtDebug(config_file_domain, "loading file {}", path_utf8);
+	FmtDebug(config_file_domain, "loading file {}", path);
 
 	FileReader file(path);
 
@@ -247,6 +247,7 @@ ReadConfigFile(ConfigData &config_data, Path path)
 	try {
 		ReadConfigFile(config_data, reader, path.GetDirectoryName());
 	} catch (...) {
+		const std::string path_utf8 = path.ToUTF8();
 		std::throw_with_nested(FormatRuntimeError("Error in %s line %u",
 							  path_utf8.c_str(),
 							  reader.GetLineNumber()));

src/db/plugins/simple/SimpleDatabasePlugin.cxx

@@ -33,12 +33,14 @@
 #include "DatabaseSave.hxx"
 #include "db/DatabaseLock.hxx"
 #include "db/DatabaseError.hxx"
+#include "lib/fmt/PathFormatter.hxx"
 #include "fs/io/TextFile.hxx"
 #include "io/BufferedOutputStream.hxx"
 #include "io/FileOutputStream.hxx"
 #include "fs/FileInfo.hxx"
 #include "config/Block.hxx"
 #include "fs/FileSystem.hxx"
+#include "system/FmtError.hxx"
 #include "util/CharUtil.hxx"
 #include "util/Domain.hxx"
 #include "util/RecursiveMap.hxx"
@@ -119,12 +121,8 @@ SimpleDatabase::Check() const
 
 #ifndef _WIN32
 		/* Check if we can write to the directory */
-		if (!CheckAccess(dirPath, X_OK | W_OK)) {
+		if (!CheckAccess(dirPath, X_OK | W_OK))
-			const int e = errno;
+			throw FmtErrno("Can't create db file in \"{}\"", dirPath);
-			const std::string dirPath_utf8 = dirPath.ToUTF8();
-			throw FormatErrno(e, "Can't create db file in \"%s\"",
-					  dirPath_utf8.c_str());
-		}
 #endif
 
 		return;
@@ -139,8 +137,8 @@ SimpleDatabase::Check() const
 #ifndef _WIN32
 	/* And check that we can write to it */
 	if (!CheckAccess(path, R_OK | W_OK))
-		throw FormatErrno("Can't open db file \"%s\" for reading/writing",
+		throw FmtErrno("Can't open db file \"{}\" for reading/writing",
-				  path_utf8.c_str());
+			       path);
 #endif
 }
 

src/event/InotifyEvent.cxx

@@ -31,7 +31,7 @@
  */
 
 #include "InotifyEvent.hxx"
-#include "system/Error.hxx"
+#include "system/FmtError.hxx"
 #include "io/UniqueFileDescriptor.hxx"
 
 #include <array>
@@ -68,7 +68,7 @@ InotifyEvent::AddWatch(const char *pathname, uint32_t mask)
 	int wd = inotify_add_watch(event.GetFileDescriptor().Get(),
 				   pathname, mask);
 	if (wd < 0)
-		throw FormatErrno("inotify_add_watch('%s') failed", pathname);
+		throw FmtErrno("inotify_add_watch('{}') failed", pathname);
 
 	return wd;
 }

src/fs/DirectoryReader.cxx

@@ -18,7 +18,8 @@
  */
 
 #include "DirectoryReader.hxx"
-#include "system/Error.hxx"
+#include "lib/fmt/PathFormatter.hxx"
+#include "system/FmtError.hxx"
 
 #ifdef _WIN32
 
@@ -28,7 +29,7 @@ DirectoryReader::DirectoryReader(Path dir)
 	:handle(FindFirstFile(MakeWildcardPath(dir.c_str()), &data))
 {
 	if (handle == INVALID_HANDLE_VALUE)
-		throw FormatLastError("Failed to open %s", dir.c_str());
+		throw FmtLastError("Failed to open {}", dir);
 }
 
 #else
@@ -37,7 +38,7 @@ DirectoryReader::DirectoryReader(Path dir)
 	:dirp(opendir(dir.c_str()))
 {
 	if (dirp == nullptr)
-		throw FormatErrno("Failed to open %s", dir.c_str());
+		throw FmtErrno("Failed to open {}", dir);
 }
 
 #endif

src/fs/FileInfo.hxx

@@ -21,7 +21,8 @@
 #define MPD_FS_FILE_INFO_HXX
 
 #include "Path.hxx"
-#include "system/Error.hxx"
+#include "lib/fmt/PathFormatter.hxx"
+#include "system/FmtError.hxx"
 
 #ifdef _WIN32
 #include "time/FileTime.hxx"
@@ -49,11 +50,9 @@ public:
 	FileInfo(Path path, bool follow_symlinks=true) {
 		if (!GetFileInfo(path, *this, follow_symlinks)) {
 #ifdef _WIN32
-			throw FormatLastError("Failed to access %s",
+			throw FmtLastError("Failed to access {}", path);
-					      path.ToUTF8().c_str());
 #else
-			throw FormatErrno("Failed to access %s",
+			throw FmtErrno("Failed to access {}", path);
-					  path.ToUTF8().c_str());
 #endif
 		}
 	}

src/fs/FileSystem.cxx

@@ -20,7 +20,8 @@
 #include "FileSystem.hxx"
 #include "AllocatedPath.hxx"
 #include "Limits.hxx"
-#include "system/Error.hxx"
+#include "lib/fmt/PathFormatter.hxx"
+#include "system/FmtError.hxx"
 
 #ifdef _WIN32
 #include <handleapi.h> // for CloseHandle()
@@ -73,13 +74,13 @@ TruncateFile(Path path)
 			      TRUNCATE_EXISTING, FILE_ATTRIBUTE_NORMAL,
 			      nullptr);
 	if (h == INVALID_HANDLE_VALUE)
-		throw FormatLastError("Failed to truncate %s", path.c_str());
+		throw FmtLastError("Failed to truncate {}", path);
 
 	CloseHandle(h);
 #else
 	UniqueFileDescriptor fd;
 	if (!fd.Open(path.c_str(), O_WRONLY|O_TRUNC))
-		throw FormatErrno("Failed to truncate %s", path.c_str());
+		throw FmtErrno("Failed to truncate {}", path);
 #endif
 }
 
@@ -88,9 +89,9 @@ RemoveFile(Path path)
 {
 #ifdef _WIN32
 	if (!DeleteFile(path.c_str()))
-		throw FormatLastError("Failed to delete %s", path.c_str());
+		throw FmtLastError("Failed to delete {}", path);
 #else
 	if (unlink(path.c_str()) < 0)
-		throw FormatErrno("Failed to delete %s", path.c_str());
+		throw FmtErrno("Failed to delete {}", path);
 #endif
 }

src/input/plugins/UringInputPlugin.cxx

@@ -21,7 +21,7 @@
 #include "../AsyncInputStream.hxx"
 #include "event/Call.hxx"
 #include "event/Loop.hxx"
-#include "system/Error.hxx"
+#include "system/FmtError.hxx"
 #include "io/Open.hxx"
 #include "io/UniqueFileDescriptor.hxx"
 #include "io/uring/ReadOperation.hxx"
@@ -188,7 +188,7 @@ OpenUringInputStream(const char *path, Mutex &mutex)
 	// TODO: use IORING_OP_STATX
 	struct stat st;
 	if (fstat(fd.Get(), &st) < 0)
-		throw FormatErrno("Failed to access %s", path);
+		throw FmtErrno("Failed to access {}", path);
 
 	if (!S_ISREG(st.st_mode))
 		throw FormatRuntimeError("Not a regular file: %s", path);

src/io/FileOutputStream.cxx

@@ -28,7 +28,8 @@
  */
 
 #include "FileOutputStream.hxx"
-#include "system/Error.hxx"
+#include "lib/fmt/PathFormatter.hxx"
+#include "system/FmtError.hxx"
 #include "util/StringFormat.hxx"
 
 #ifdef _WIN32
@@ -106,8 +107,7 @@ FileOutputStream::OpenCreate(bool visible)
 			    FILE_ATTRIBUTE_NORMAL|FILE_FLAG_WRITE_THROUGH,
 			    nullptr);
 	if (!IsDefined())
-		throw FormatLastError("Failed to create %s",
+		throw FmtLastError("Failed to create {}", path);
-				      path.ToUTF8().c_str());
 }
 
 inline void
@@ -118,14 +118,12 @@ FileOutputStream::OpenAppend(bool create)
 			    FILE_ATTRIBUTE_NORMAL|FILE_FLAG_WRITE_THROUGH,
 			    nullptr);
 	if (!IsDefined())
-		throw FormatLastError("Failed to append to %s",
+		throw FmtLastError("Failed to append to {}", path);
-				      path.ToUTF8().c_str());
 
 	if (!SeekEOF()) {
 		auto code = GetLastError();
 		Close();
-		throw FormatLastError(code, "Failed seek end-of-file of %s",
+		throw FmtLastError(code, "Failed seek end-of-file of {}", path);
-				      path.ToUTF8().c_str());
 	}
 
 }
@@ -148,12 +146,12 @@ FileOutputStream::Write(const void *data, size_t size)
 
 	DWORD nbytes;
 	if (!WriteFile(handle, data, size, &nbytes, nullptr))
-		throw FormatLastError("Failed to write to %s",
+		throw FmtLastError("Failed to write to {}", GetPath());
-				      GetPath().c_str());
 
 	if (size_t(nbytes) != size)
-		throw FormatLastError(ERROR_DISK_FULL, "Failed to write to %s",
+		throw FmtLastError(DWORD{ERROR_DISK_FULL},
-				      GetPath().c_str());
+				   "Failed to write to {}",
+				   GetPath());
 }
 
 void
@@ -162,7 +160,7 @@ FileOutputStream::Sync()
 	assert(IsDefined());
 
 	if (!FlushFileBuffers(handle))
-		throw FormatLastError("Failed to sync %s", GetPath().c_str());
+		throw FmtLastError("Failed to sync {}", GetPath());
 }
 
 void
@@ -249,8 +247,7 @@ FileOutputStream::OpenCreate([[maybe_unused]] bool visible)
 		    GetPath().c_str(),
 		    O_WRONLY|O_CREAT|O_TRUNC,
 		    0666))
-		throw FormatErrno("Failed to create %s",
+		throw FmtErrno("Failed to create {}", GetPath());
-				  GetPath().c_str());
 }
 
 inline void
@@ -265,8 +262,7 @@ FileOutputStream::OpenAppend(bool create)
 		     directory_fd,
 #endif
 		     path.c_str(), flags))
-		throw FormatErrno("Failed to append to %s",
+		throw FmtErrno("Failed to append to {}", path);
-				  path.c_str());
 }
 
 uint64_t
@@ -282,10 +278,9 @@ FileOutputStream::Write(const void *data, size_t size)
 
 	ssize_t nbytes = fd.Write(data, size);
 	if (nbytes < 0)
-		throw FormatErrno("Failed to write to %s", GetPath().c_str());
+		throw FmtErrno("Failed to write to {}", GetPath());
 	else if ((size_t)nbytes < size)
-		throw FormatErrno(ENOSPC, "Failed to write to %s",
+		throw FmtErrno(ENOSPC, "Failed to write to {}", GetPath());
-				  GetPath().c_str());
 }
 
 void
@@ -299,7 +294,7 @@ FileOutputStream::Sync()
 	const bool success = fsync(fd.Get()) == 0;
 #endif
 	if (!success)
-		throw FormatErrno("Failed to sync %s", GetPath().c_str());
+		throw FmtErrno("Failed to sync {}", GetPath());
 }
 
 void
@@ -316,13 +311,12 @@ try {
 			   StringFormat<64>("/proc/self/fd/%d", fd.Get()),
 			   directory_fd.Get(), path.c_str(),
 			   AT_SYMLINK_FOLLOW) < 0)
-			throw FormatErrno("Failed to commit %s",
+			throw FmtErrno("Failed to commit {}", path);
-					  path.c_str());
 	}
 #endif
 
 	if (!Close()) {
-		throw FormatErrno("Failed to commit %s", path.c_str());
+		throw FmtErrno("Failed to commit {}", path);
 	}
 
 	if (tmp_path != nullptr)

src/io/FileReader.cxx

@@ -28,8 +28,9 @@
  */
 
 #include "FileReader.hxx"
+#include "lib/fmt/PathFormatter.hxx"
 #include "fs/FileInfo.hxx"
-#include "system/Error.hxx"
+#include "system/FmtError.hxx"
 #include "io/Open.hxx"
 
 #include <cassert>
@@ -43,7 +44,7 @@ FileReader::FileReader(Path _path)
 			   nullptr))
 {
 	if (handle == INVALID_HANDLE_VALUE)
-		throw FormatLastError("Failed to open %s", path.ToUTF8().c_str());
+		throw FmtLastError("Failed to open {}", path);
 }
 
 FileInfo
@@ -61,8 +62,7 @@ FileReader::Read(void *data, std::size_t size)
 
 	DWORD nbytes;
 	if (!ReadFile(handle, data, size, &nbytes, nullptr))
-		throw FormatLastError("Failed to read from %s",
+		throw FmtLastError("Failed to read from %s", path);
-				      path.ToUTF8().c_str());
 
 	return nbytes;
 }
@@ -110,8 +110,7 @@ FileReader::GetFileInfo() const
 	FileInfo info;
 	const bool success = fstat(fd.Get(), &info.st) == 0;
 	if (!success)
-		throw FormatErrno("Failed to access %s",
+		throw FmtErrno("Failed to access {}", path);
-				  path.ToUTF8().c_str());
 
 	return info;
 }
@@ -123,7 +122,7 @@ FileReader::Read(void *data, std::size_t size)
 
 	ssize_t nbytes = fd.Read(data, size);
 	if (nbytes < 0)
-		throw FormatErrno("Failed to read from %s", path.ToUTF8().c_str());
+		throw FmtErrno("Failed to read from {}", path);
 
 	return nbytes;
 }

src/io/Open.cxx

@@ -29,7 +29,7 @@
 
 #include "Open.hxx"
 #include "UniqueFileDescriptor.hxx"
-#include "system/Error.hxx"
+#include "system/FmtError.hxx"
 
 #include <fcntl.h>
 
@@ -38,7 +38,7 @@ OpenReadOnly(const char *path, int flags)
 {
 	UniqueFileDescriptor fd;
 	if (!fd.Open(path, O_RDONLY|flags))
-		throw FormatErrno("Failed to open '%s'", path);
+		throw FmtErrno("Failed to open '{}'", path);
 
 	return fd;
 }
@@ -48,7 +48,7 @@ OpenWriteOnly(const char *path, int flags)
 {
 	UniqueFileDescriptor fd;
 	if (!fd.Open(path, O_WRONLY|flags))
-		throw FormatErrno("Failed to open '%s'", path);
+		throw FmtErrno("Failed to open '{}'", path);
 
 	return fd;
 }
@@ -60,7 +60,7 @@ OpenDirectory(const char *path, int flags)
 {
 	UniqueFileDescriptor fd;
 	if (!fd.Open(path, O_DIRECTORY|O_RDONLY|flags))
-		throw FormatErrno("Failed to open '%s'", path);
+		throw FmtErrno("Failed to open '{}'", path);
 
 	return fd;
 }
@@ -74,7 +74,7 @@ OpenPath(const char *path, int flags)
 {
 	UniqueFileDescriptor fd;
 	if (!fd.Open(path, O_PATH|flags))
-		throw FormatErrno("Failed to open '%s'", path);
+		throw FmtErrno("Failed to open '{}'", path);
 
 	return fd;
 }
@@ -84,7 +84,7 @@ OpenPath(FileDescriptor directory, const char *name, int flags)
 {
 	UniqueFileDescriptor fd;
 	if (!fd.Open(directory, name, O_PATH|flags))
-		throw FormatErrno("Failed to open '%s'", name);
+		throw FmtErrno("Failed to open '{}'", name);
 
 	return fd;
 }
@@ -94,7 +94,7 @@ OpenReadOnly(FileDescriptor directory, const char *name, int flags)
 {
 	UniqueFileDescriptor fd;
 	if (!fd.Open(directory, name, O_RDONLY|flags))
-		throw FormatErrno("Failed to open '%s'", name);
+		throw FmtErrno("Failed to open '{}'", name);
 
 	return fd;
 }
@@ -104,7 +104,7 @@ OpenWriteOnly(FileDescriptor directory, const char *name, int flags)
 {
 	UniqueFileDescriptor fd;
 	if (!fd.Open(directory, name, O_WRONLY|flags))
-		throw FormatErrno("Failed to open '%s'", name);
+		throw FmtErrno("Failed to open '{}'", name);
 
 	return fd;
 }
@@ -114,7 +114,7 @@ OpenDirectory(FileDescriptor directory, const char *name, int flags)
 {
 	UniqueFileDescriptor fd;
 	if (!fd.Open(directory, name, O_DIRECTORY|O_RDONLY|flags))
-		throw FormatErrno("Failed to open '%s'", name);
+		throw FmtErrno("Failed to open '{}'", name);
 
 	return fd;
 }

src/lib/jack/Dynamic.hxx

@@ -118,7 +118,7 @@ LoadJackLibrary()
 
 	auto libjack = LoadLibraryA(LIBJACK);
 	if (!libjack)
-		throw FormatLastError("Failed to load " LIBJACK ".dll");
+		throw MakeLastError("Failed to load " LIBJACK ".dll");
 
 	GetFunction(libjack, "jack_set_error_function", _jack_set_error_function);
 	GetFunction(libjack, "jack_set_info_function", _jack_set_info_function);

src/mixer/plugins/OssMixerPlugin.cxx

@@ -21,7 +21,7 @@
 #include "mixer/Mixer.hxx"
 #include "config/Block.hxx"
 #include "io/FileDescriptor.hxx"
-#include "system/Error.hxx"
+#include "system/FmtError.hxx"
 #include "util/ASCII.hxx"
 #include "util/Domain.hxx"
 #include "util/RuntimeError.hxx"
@@ -119,7 +119,7 @@ OssMixer::Open()
 {
 	device_fd.OpenReadOnly(device);
 	if (!device_fd.IsDefined())
-		throw FormatErrno("failed to open %s", device);
+		throw FmtErrno("failed to open {}", device);
 
 	try {
 		if (control) {
@@ -129,8 +129,8 @@ OssMixer::Open()
 				throw MakeErrno("READ_DEVMASK failed");
 
 			if (((1 << volume_control) & devmask) == 0)
-				throw FormatErrno("mixer control \"%s\" not usable",
+				throw FmtErrno("mixer control \"{}\" not usable",
-						  control);
+					       control);
 		}
 	} catch (...) {
 		Close();

src/output/plugins/FifoOutputPlugin.cxx

@@ -20,9 +20,11 @@
 #include "FifoOutputPlugin.hxx"
 #include "../OutputAPI.hxx"
 #include "../Timer.hxx"
+#include "lib/fmt/PathFormatter.hxx"
 #include "fs/AllocatedPath.hxx"
 #include "fs/FileSystem.hxx"
 #include "fs/FileInfo.hxx"
+#include "system/FmtError.hxx"
 #include "util/Domain.hxx"
 #include "util/RuntimeError.hxx"
 #include "Log.hxx"
@@ -91,7 +93,7 @@ inline void
 FifoOutput::Delete()
 {
 	FmtDebug(fifo_output_domain,
-		 "Removing FIFO \"{}\"", path_utf8);
+		 "Removing FIFO \"{}\"", path);
 
 	try {
 		RemoveFile(path);
@@ -125,8 +127,7 @@ inline void
 FifoOutput::Create()
 {
 	if (!MakeFifo(path, 0666))
-		throw FormatErrno("Couldn't create FIFO \"%s\"",
+		throw FmtErrno("Couldn't create FIFO \"{}\"", path);
-				  path_utf8.c_str());
 
 	created = true;
 }
@@ -142,8 +143,7 @@ FifoOutput::Check()
 			return;
 		}
 
-		throw FormatErrno("Failed to stat FIFO \"%s\"",
+		throw FmtErrno("Failed to stat FIFO \"{}\"", path);
-				  path_utf8.c_str());
 	}
 
 	if (!S_ISFIFO(st.st_mode))
@@ -158,13 +158,12 @@ try {
 
 	input = OpenFile(path, O_RDONLY|O_NONBLOCK|O_BINARY, 0).Steal();
 	if (input < 0)
-		throw FormatErrno("Could not open FIFO \"%s\" for reading",
+		throw FmtErrno("Could not open FIFO \"{}\" for reading",
-				  path_utf8.c_str());
+			       path);
 
 	output = OpenFile(path, O_WRONLY|O_NONBLOCK|O_BINARY, 0).Steal();
 	if (output < 0)
-		throw FormatErrno("Could not open FIFO \"%s\" for writing",
+		throw FmtErrno("Could not open FIFO \"{}\" for writing");
-				  path_utf8.c_str());
 } catch (...) {
 	CloseFifo();
 	throw;
@@ -196,7 +195,7 @@ FifoOutput::Cancel() noexcept
 	if (bytes < 0 && errno != EAGAIN) {
 		FmtError(fifo_output_domain,
 			 "Flush of FIFO \"{}\" failed: {}",
-			 path_utf8, strerror(errno));
+			 path, strerror(errno));
 	}
 }
 
@@ -230,8 +229,7 @@ FifoOutput::Play(std::span<const std::byte> src)
 				continue;
 			}
 
-			throw FormatErrno("Failed to write to FIFO %s",
+			throw FmtErrno("Failed to write to FIFO {}", path);
-					  path_utf8.c_str());
 		}
 	}
 }

src/output/plugins/OssOutputPlugin.cxx

@@ -22,7 +22,7 @@
 #include "mixer/plugins/OssMixerPlugin.hxx"
 #include "pcm/Export.hxx"
 #include "io/UniqueFileDescriptor.hxx"
-#include "system/Error.hxx"
+#include "system/FmtError.hxx"
 #include "util/Domain.hxx"
 #include "util/ByteOrder.hxx"
 #include "util/Manual.hxx"
@@ -643,7 +643,7 @@ try {
 	assert(!fd.IsDefined());
 
 	if (!fd.Open(device, O_WRONLY))
-		throw FormatErrno("Error opening OSS device \"%s\"", device);
+		throw FmtErrno("Error opening OSS device \"{}\"", device);
 
 	OssIoctlExact(fd, SNDCTL_DSP_CHANNELS, effective_channels,
 		      "Failed to set channel count");
@@ -660,7 +660,7 @@ void
 OssOutput::Open(AudioFormat &_audio_format)
 try {
 	if (!fd.Open(device, O_WRONLY))
-		throw FormatErrno("Error opening OSS device \"%s\"", device);
+		throw FmtErrno("Error opening OSS device \"{}\"", device);
 
 	SetupOrDop(_audio_format);
 } catch (...) {
@@ -698,7 +698,7 @@ OssOutput::Play(std::span<const std::byte> src)
 			return pcm_export->CalcInputSize(ret);
 
 		if (ret < 0 && errno != EINTR)
-			throw FormatErrno("Write error on %s", device);
+			throw FmtErrno("Write error on {}", device);
 	}
 }
 

src/output/plugins/PipeOutputPlugin.cxx

@@ -19,7 +19,7 @@
 
 #include "PipeOutputPlugin.hxx"
 #include "../OutputAPI.hxx"
-#include "system/Error.hxx"
+#include "system/FmtError.hxx"
 
 #include <string>
 #include <stdexcept>
@@ -61,7 +61,7 @@ PipeOutput::Open([[maybe_unused]] AudioFormat &audio_format)
 {
 	fh = popen(cmd.c_str(), "w");
 	if (fh == nullptr)
-		throw FormatErrno("Error opening pipe \"%s\"", cmd.c_str());
+		throw FmtErrno("Error opening pipe \"{}\"", cmd);
 }
 
 std::size_t

src/output/plugins/SolarisOutputPlugin.cxx

@@ -20,7 +20,7 @@
 #include "SolarisOutputPlugin.hxx"
 #include "../OutputAPI.hxx"
 #include "io/FileDescriptor.hxx"
-#include "system/Error.hxx"
+#include "system/FmtError.hxx"
 
 #include <cerrno>
 
@@ -100,8 +100,7 @@ SolarisOutput::Open(AudioFormat &audio_format)
 	/* open the device in non-blocking mode */
 
 	if (!fd.Open(device, O_WRONLY|O_NONBLOCK))
-		throw FormatErrno("Failed to open %s",
+		throw FmtErrno("Failed to open {}", device);
-				  device);
 
 	/* restore blocking mode */
 

src/system/Error.hxx

@@ -32,8 +32,6 @@
 #include <system_error> // IWYU pragma: export
 #include <utility>
 
-#include <stdio.h>
-
 template<typename... Args>
 static inline std::system_error
 FormatSystemError(std::error_code code, const char *fmt,
@@ -47,8 +45,7 @@ FormatSystemError(std::error_code code, const char *fmt,
 #ifdef _WIN32
 
 #include <errhandlingapi.h> // for GetLastError()
-#include <windef.h> // for HWND (needed by winbase.h)
+#include <winerror.h>
-#include <winbase.h> // for FormatMessageA()
 
 /**
  * Returns the error_category to be used to wrap WIN32 GetLastError()
@@ -85,41 +82,10 @@ MakeLastError(const char *msg) noexcept
 	return MakeLastError(GetLastError(), msg);
 }
 
-template<typename... Args>
-static inline std::system_error
-FormatLastError(DWORD code, const char *fmt, Args&&... args) noexcept
-{
-	char buffer[512];
-	const auto end = buffer + sizeof(buffer);
-	constexpr std::size_t max_prefix = sizeof(buffer) - 128;
-	size_t length = snprintf(buffer, max_prefix,
-				 fmt, std::forward<Args>(args)...);
-	if (length >= max_prefix)
-		length = max_prefix - 1;
-	char *p = buffer + length;
-	*p++ = ':';
-	*p++ = ' ';
-
-	FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM |
-		       FORMAT_MESSAGE_IGNORE_INSERTS,
-		       nullptr, code, 0, p, end - p, nullptr);
-	return MakeLastError(code, buffer);
-}
-
-template<typename... Args>
-static inline std::system_error
-FormatLastError(const char *fmt, Args&&... args) noexcept
-{
-	return FormatLastError(GetLastError(), fmt,
-			       std::forward<Args>(args)...);
-}
-
 #endif /* _WIN32 */
 
 #include <cerrno> // IWYU pragma: export
 
-#include <string.h>
-
 /**
  * Returns the error_category to be used to wrap errno values.  The
  * C++ standard does not define this well, so this code is based on
@@ -156,35 +122,6 @@ MakeErrno(const char *msg) noexcept
 	return MakeErrno(errno, msg);
 }
 
-template<typename... Args>
-static inline std::system_error
-FormatErrno(int code, const char *fmt, Args&&... args) noexcept
-{
-	char buffer[512];
-	snprintf(buffer, sizeof(buffer),
-		 fmt, std::forward<Args>(args)...);
-	return MakeErrno(code, buffer);
-}
-
-template<typename... Args>
-static inline std::system_error
-FormatErrno(const char *fmt, Args&&... args) noexcept
-{
-	return FormatErrno(errno, fmt, std::forward<Args>(args)...);
-}
-
-template<typename... Args>
-static inline std::system_error
-FormatFileNotFound(const char *fmt, Args&&... args) noexcept
-{
-#ifdef _WIN32
-	return FormatLastError(ERROR_FILE_NOT_FOUND, fmt,
-			       std::forward<Args>(args)...);
-#else
-	return FormatErrno(ENOENT, fmt, std::forward<Args>(args)...);
-#endif
-}
-
 [[gnu::pure]]
 inline bool
 IsErrno(const std::system_error &e, int code) noexcept

src/system/FmtError.cxx

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2022 Max Kellermann <max.kellermann@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "FmtError.hxx"
+
+#include <fmt/format.h>
+
+#include <array>
+
+std::system_error
+VFmtSystemError(std::error_code code,
+		fmt::string_view format_str, fmt::format_args args) noexcept
+{
+	std::array<char, 512> buffer;
+	auto [p, _] = fmt::vformat_to_n(buffer.begin(), buffer.size() - 1,
+					format_str, args);
+	*p = 0;
+	return std::system_error{code, buffer.data()};
+}
+
+#ifdef _WIN32
+
+#include <windef.h> // for HWND (needed by winbase.h)
+#include <winbase.h> // for FormatMessageA()
+
+std::system_error
+VFmtLastError(DWORD code,
+	      fmt::string_view format_str, fmt::format_args args) noexcept
+{
+	std::array<char, 512> buffer;
+	const auto end = buffer.data() + buffer.size();
+
+	constexpr std::size_t max_prefix = sizeof(buffer) - 128;
+	auto [p, _] = fmt::vformat_to_n(buffer.data(),
+					buffer.size() - max_prefix,
+					format_str, args);
+	*p++ = ':';
+	*p++ = ' ';
+
+	FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM |
+		       FORMAT_MESSAGE_IGNORE_INSERTS,
+		       nullptr, code, 0, p, end - p, nullptr);
+
+	return MakeLastError(code, buffer.data());
+}
+
+#endif // _WIN32

src/system/FmtError.hxx

@@ -0,0 +1,122 @@
+/*
+ * Copyright 2022 Max Kellermann <max.kellermann@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include "Error.hxx" // IWYU pragma: export
+
+#include <fmt/core.h>
+#if FMT_VERSION >= 80000 && FMT_VERSION < 90000
+#include <fmt/format.h>
+#endif
+
+[[nodiscard]] [[gnu::pure]]
+std::system_error
+VFmtSystemError(std::error_code code,
+		fmt::string_view format_str, fmt::format_args args) noexcept;
+
+template<typename S, typename... Args>
+[[nodiscard]] [[gnu::pure]]
+std::system_error
+FmtSystemError(std::error_code code,
+	       const S &format_str, Args&&... args) noexcept
+{
+#if FMT_VERSION >= 90000
+	return VFmtSystemError(code, format_str,
+			       fmt::make_format_args(args...));
+#else
+	return VFmtSystemError(code, fmt::to_string_view(format_str),
+			       fmt::make_args_checked<Args...>(format_str,
+							       args...));
+#endif
+}
+
+#ifdef _WIN32
+
+[[nodiscard]] [[gnu::pure]]
+std::system_error
+VFmtLastError(DWORD code,
+	      fmt::string_view format_str, fmt::format_args args) noexcept;
+
+template<typename S, typename... Args>
+[[nodiscard]] [[gnu::pure]]
+std::system_error
+FmtLastError(DWORD code,
+	     const S &format_str, Args&&... args) noexcept
+{
+#if FMT_VERSION >= 90000
+	return VFmtLastError(code, format_str,
+			     fmt::make_format_args(args...));
+#else
+	return VFmtLastError(code, fmt::to_string_view(format_str),
+			     fmt::make_args_checked<Args...>(format_str,
+							     args...));
+#endif
+}
+
+template<typename S, typename... Args>
+[[nodiscard]] [[gnu::pure]]
+std::system_error
+FmtLastError(const S &format_str, Args&&... args) noexcept
+{
+	return FmtLastError(GetLastError(),
+			    format_str, std::forward<Args>(args)...);
+}
+
+#endif // _WIN32
+
+template<typename S, typename... Args>
+[[nodiscard]] [[gnu::pure]]
+std::system_error
+FmtErrno(int code, const S &format_str, Args&&... args) noexcept
+{
+	return FmtSystemError(std::error_code(code, ErrnoCategory()),
+			      format_str, std::forward<Args>(args)...);
+}
+
+template<typename S, typename... Args>
+[[nodiscard]] [[gnu::pure]]
+std::system_error
+FmtErrno(const S &format_str, Args&&... args) noexcept
+{
+	return FmtErrno(errno, format_str, std::forward<Args>(args)...);
+}
+
+template<typename S, typename... Args>
+[[nodiscard]] [[gnu::pure]]
+std::system_error
+FmtFileNotFound(const S &format_str, Args&&... args) noexcept
+{
+#ifdef _WIN32
+	return FmtLastError(DWORD{ERROR_FILE_NOT_FOUND},
+			    format_str, std::forward<Args>(args)...);
+#else
+	return FmtErrno(ENOENT, format_str, std::forward<Args>(args)...);
+#endif
+}

src/system/meson.build

@@ -1,5 +1,6 @@
 system_sources = [
   'EventPipe.cxx',
+  'FmtError.cxx',
 ]
 
 if host_machine.system() == 'linux'

src/unix/Daemon.cxx

@@ -19,7 +19,8 @@
 
 #include "config.h"
 #include "Daemon.hxx"
-#include "system/Error.hxx"
+#include "lib/fmt/PathFormatter.hxx"
+#include "system/FmtError.hxx"
 #include "fs/AllocatedPath.hxx"
 #include "util/RuntimeError.hxx"
 
@@ -70,14 +71,12 @@ daemonize_kill()
 		throw std::runtime_error("no pid_file specified in the config file");
 
 	const pid_t pid = ReadPidFile(pidfile);
-	if (pid < 0) {
+	if (pid < 0)
-		const std::string utf8 = pidfile.ToUTF8();
+		throw FmtErrno("unable to read the pid from file \"{}\"",
-		throw FormatErrno("unable to read the pid from file \"%s\"",
+			       pidfile);
-				  utf8.c_str());
-	}
 
 	if (kill(pid, SIGTERM) < 0)
-		throw FormatErrno("unable to kill process %i", int(pid));
+		throw FmtErrno("unable to kill process {}", pid);
 
 	std::exit(EXIT_SUCCESS);
 }
@@ -98,7 +97,7 @@ daemonize_set_user()
 	/* set gid */
 	if (user_gid != (gid_t)-1 && user_gid != getgid() &&
 	    setgid(user_gid) == -1) {
-		throw FormatErrno("Failed to set group %d", (int)user_gid);
+		throw FmtErrno("Failed to set group {}", user_gid);
 	}
 
 #ifdef HAVE_INITGROUPS
@@ -110,16 +109,16 @@ daemonize_set_user()
 	       we are already this user */
 	    user_uid != getuid() &&
 	    initgroups(user_name, user_gid) == -1) {
-		throw FormatErrno("Failed to set supplementary groups "
+		throw FmtErrno("Failed to set supplementary groups "
-				  "of user \"%s\"",
+			       "of user \"{}\"",
-				  user_name);
+			       user_name);
 	}
 #endif
 
 	/* set uid */
 	if (user_uid != (uid_t)-1 && user_uid != getuid() &&
 	    setuid(user_uid) == -1) {
-		throw FormatErrno("Failed to set user \"%s\"", user_name);
+		throw FmtErrno("Failed to set user \"{}\"", user_name);
 	}
 }
 
@@ -191,8 +190,8 @@ daemonize_begin(bool detach)
 		throw MakeErrno("waitpid() failed");
 
 	if (WIFSIGNALED(status))
-		throw FormatErrno("MPD died from signal %d%s", WTERMSIG(status),
+		throw FmtErrno("MPD died from signal {}{}", WTERMSIG(status),
-				  WCOREDUMP(status) ? " (core dumped)" : "");
+			       WCOREDUMP(status) ? " (core dumped)" : "");
 
 	std::exit(WEXITSTATUS(status));
 }

src/unix/PidFile.hxx

@@ -20,9 +20,10 @@
 #ifndef MPD_PID_FILE_HXX
 #define MPD_PID_FILE_HXX
 
+#include "lib/fmt/PathFormatter.hxx"
 #include "fs/FileSystem.hxx"
 #include "fs/AllocatedPath.hxx"
-#include "system/Error.hxx"
+#include "system/FmtError.hxx"
 
 #include <cassert>
 
@@ -40,11 +41,9 @@ public:
 			return;
 
 		fd = OpenFile(path, O_WRONLY|O_CREAT|O_TRUNC, 0666).Steal();
-		if (fd < 0) {
+		if (fd < 0)
-			const std::string utf8 = path.ToUTF8();
+			throw FmtErrno("Failed to create pid file \"{}\"",
-			throw FormatErrno("Failed to create pid file \"%s\"",
+				       path);
-					  utf8.c_str());
-		}
 	}
 
 	PidFile(const PidFile &) = delete;

src/win32/WinEvent.cxx

@@ -24,5 +24,5 @@ WinEvent::WinEvent()
 	:event(CreateEventW(nullptr, false, false, nullptr))
 {
 	if (!event)
-		throw FormatLastError("Error creating events");
+		throw MakeLastError("Error creating events");
 }