db/simple/Save: migrate from class Error to C++ exceptions

src/PlaylistDatabase.cxx

@@ -23,14 +23,11 @@
 #include "fs/io/TextFile.hxx"
 #include "fs/io/BufferedOutputStream.hxx"
 #include "util/StringUtil.hxx"
-#include "util/Error.hxx"
-#include "util/Domain.hxx"
+#include "util/RuntimeError.hxx"
 
 #include <string.h>
 #include <stdlib.h>
 
-static constexpr Domain playlist_database_domain("playlist_database");
-
 void
 playlist_vector_save(BufferedOutputStream &os, const PlaylistVector &pv)
 {
@@ -41,9 +38,8 @@ playlist_vector_save(BufferedOutputStream &os, const PlaylistVector &pv)
 			  pi.name.c_str(), (long)pi.mtime);
 }
 
-bool
-playlist_metadata_load(TextFile &file, PlaylistVector &pv, const char *name,
-		       Error &error)
+void
+playlist_metadata_load(TextFile &file, PlaylistVector &pv, const char *name)
 {
 	PlaylistInfo pm(name, 0);
 
@@ -53,24 +49,19 @@ playlist_metadata_load(TextFile &file, PlaylistVector &pv, const char *name,
 	while ((line = file.ReadLine()) != nullptr &&
 	       strcmp(line, "playlist_end") != 0) {
 		colon = strchr(line, ':');
-		if (colon == nullptr || colon == line) {
-			error.Format(playlist_database_domain,
-				     "unknown line in db: %s", line);
-			return false;
-		}
+		if (colon == nullptr || colon == line)
+			throw FormatRuntimeError("unknown line in db: %s",
+						 line);
 
 		*colon++ = 0;
 		value = StripLeft(colon);
 
 		if (strcmp(line, "mtime") == 0)
 			pm.mtime = strtol(value, nullptr, 10);
-		else {
-			error.Format(playlist_database_domain,
-				     "unknown line in db: %s", line);
-			return false;
-		}
+		else
+			throw FormatRuntimeError("unknown line in db: %s",
+						 line);
 	}
 
 	pv.UpdateOrInsert(std::move(pm));
-	return true;
 }

src/PlaylistDatabase.hxx

@@ -32,8 +32,10 @@ class Error;
 void
 playlist_vector_save(BufferedOutputStream &os, const PlaylistVector &pv);
 
-bool
-playlist_metadata_load(TextFile &file, PlaylistVector &pv, const char *name,
-		       Error &error);
+/**
+ * Throws #std::runtime_error on error.
+ */
+void
+playlist_metadata_load(TextFile &file, PlaylistVector &pv, const char *name);
 
 #endif

src/SongSave.cxx

@@ -27,8 +27,7 @@
 #include "tag/Tag.hxx"
 #include "tag/TagBuilder.hxx"
 #include "util/StringUtil.hxx"
-#include "util/Error.hxx"
-#include "util/Domain.hxx"
+#include "util/RuntimeError.hxx"
 
 #include <string.h>
 #include <stdlib.h>
@@ -36,8 +35,6 @@
 #define SONG_MTIME "mtime"
 #define SONG_END "song_end"
 
-static constexpr Domain song_save_domain("song_save");
-
 static void
 range_save(BufferedOutputStream &os, unsigned start_ms, unsigned end_ms)
 {
@@ -74,8 +71,7 @@ song_save(BufferedOutputStream &os, const DetachedSong &song)
 }
 
 DetachedSong *
-song_load(TextFile &file, const char *uri,
-	  Error &error)
+song_load(TextFile &file, const char *uri)
 {
 	DetachedSong *song = new DetachedSong(uri);
 
@@ -88,9 +84,7 @@ song_load(TextFile &file, const char *uri,
 		if (colon == nullptr || colon == line) {
 			delete song;
 
-			error.Format(song_save_domain,
-				     "unknown line in db: %s", line);
-			return nullptr;
+			throw FormatRuntimeError("unknown line in db: %s", line);
 		}
 
 		*colon++ = 0;
@@ -118,9 +112,7 @@ song_load(TextFile &file, const char *uri,
 		} else {
 			delete song;
 
-			error.Format(song_save_domain,
-				     "unknown line in db: %s", line);
-			return nullptr;
+			throw FormatRuntimeError("unknown line in db: %s", line);
 		}
 	}
 

src/SongSave.hxx

@@ -38,11 +38,9 @@ song_save(BufferedOutputStream &os, const DetachedSong &song);
  * Loads a song from the input file.  Reading stops after the
  * "song_end" line.
  *
- * @param error location to store the error occurring
- * @return true on success, false on error
+ * Throws #std::runtime_error on error.
  */
 DetachedSong *
-song_load(TextFile &file, const char *uri,
-	  Error &error);
+song_load(TextFile &file, const char *uri);
 
 #endif

src/db/plugins/simple/DatabaseSave.cxx

@@ -29,7 +29,7 @@
 #include "tag/Settings.hxx"
 #include "fs/Charset.hxx"
 #include "util/StringCompare.hxx"
-#include "util/Error.hxx"
+#include "util/RuntimeError.hxx"
 #include "Log.hxx"
 
 #include <string.h>
@@ -66,8 +66,8 @@ db_save_internal(BufferedOutputStream &os, const Directory &music_root)
 	directory_save(os, music_root);
 }
 
-bool
-db_load_internal(TextFile &file, Directory &music_root, Error &error)
+void
+db_load_internal(TextFile &file, Directory &music_root)
 {
 	char *line;
 	unsigned format = 0;
@@ -76,10 +76,8 @@ db_load_internal(TextFile &file, Directory &music_root, Error &error)
 
 	/* get initial info */
 	line = file.ReadLine();
-	if (line == nullptr || strcmp(DIRECTORY_INFO_BEGIN, line) != 0) {
-		error.Set(db_domain, "Database corrupted");
-		return false;
-	}
+	if (line == nullptr || strcmp(DIRECTORY_INFO_BEGIN, line) != 0)
+		throw std::runtime_error("Database corrupted");
 
 	memset(tags, false, sizeof(tags));
 
@@ -90,67 +88,49 @@ db_load_internal(TextFile &file, Directory &music_root, Error &error)
 		if ((p = StringAfterPrefix(line, DB_FORMAT_PREFIX))) {
 			format = atoi(p);
 		} else if (StringStartsWith(line, DIRECTORY_MPD_VERSION)) {
-			if (found_version) {
-				error.Set(db_domain, "Duplicate version line");
-				return false;
-			}
+			if (found_version)
+				throw std::runtime_error("Duplicate version line");
 
 			found_version = true;
 		} else if ((p = StringAfterPrefix(line, DIRECTORY_FS_CHARSET))) {
-			if (found_charset) {
-				error.Set(db_domain, "Duplicate charset line");
-				return false;
-			}
+			if (found_charset)
+				throw std::runtime_error("Duplicate charset line");
 
 			found_charset = true;
 
 			const char *new_charset = p;
 			const char *const old_charset = GetFSCharset();
 			if (*old_charset != 0
-			    && strcmp(new_charset, old_charset) != 0) {
-				error.Format(db_domain,
-					     "Existing database has charset "
-					     "\"%s\" instead of \"%s\"; "
-					     "discarding database file",
-					     new_charset, old_charset);
-				return false;
-			}
+			    && strcmp(new_charset, old_charset) != 0)
+				throw FormatRuntimeError("Existing database has charset "
+							 "\"%s\" instead of \"%s\"; "
+							 "discarding database file",
+							 new_charset, old_charset);
 		} else if ((p = StringAfterPrefix(line, DB_TAG_PREFIX))) {
 			const char *name = p;
 			TagType tag = tag_name_parse(name);
-			if (tag == TAG_NUM_OF_ITEM_TYPES) {
-				error.Format(db_domain,
-					     "Unrecognized tag '%s', "
-					     "discarding database file",
-					     name);
-				return false;
-			}
+			if (tag == TAG_NUM_OF_ITEM_TYPES)
+				throw FormatRuntimeError("Unrecognized tag '%s', "
+							 "discarding database file",
+							 name);
 
 			tags[tag] = true;
 		} else {
-			error.Format(db_domain, "Malformed line: %s", line);
-			return false;
+			throw FormatRuntimeError("Malformed line: %s", line);
 		}
 	}
 
-	if (format < OLDEST_DB_FORMAT || format > DB_FORMAT) {
-		error.Set(db_domain,
-			  "Database format mismatch, "
-			  "discarding database file");
-		return false;
-	}
+	if (format < OLDEST_DB_FORMAT || format > DB_FORMAT)
+		throw std::runtime_error("Database format mismatch, "
+					 "discarding database file");
 
-	for (unsigned i = 0; i < TAG_NUM_OF_ITEM_TYPES; ++i) {
-		if (IsTagEnabled(i) && !tags[i]) {
-			error.Set(db_domain,
-				  "Tag list mismatch, "
-				  "discarding database file");
-			return false;
-		}
-	}
+	for (unsigned i = 0; i < TAG_NUM_OF_ITEM_TYPES; ++i)
+		if (IsTagEnabled(i) && !tags[i])
+			throw std::runtime_error("Tag list mismatch, "
+						 "discarding database file");
 
 	LogDebug(db_domain, "reading DB");
 
 	const ScopeDatabaseLock protect;
-	return directory_load(file, music_root, error);
+	directory_load(file, music_root);
 }

src/db/plugins/simple/DatabaseSave.hxx

@@ -28,7 +28,10 @@ class Error;
 void
 db_save_internal(BufferedOutputStream &os, const Directory &root);
 
-bool
-db_load_internal(TextFile &file, Directory &root, Error &error);
+/**
+ * Throws #std::runtime_error on error.
+ */
+void
+db_load_internal(TextFile &file, Directory &root);
 
 #endif

src/db/plugins/simple/DirectorySave.cxx

@@ -28,8 +28,7 @@
 #include "fs/io/BufferedOutputStream.hxx"
 #include "util/StringCompare.hxx"
 #include "util/NumberParser.hxx"
-#include "util/Error.hxx"
-#include "util/Domain.hxx"
+#include "util/RuntimeError.hxx"
 
 #include <string.h>
 
@@ -39,8 +38,6 @@
 #define DIRECTORY_BEGIN "begin: "
 #define DIRECTORY_END "end: "
 
-static constexpr Domain directory_domain("directory");
-
 gcc_const
 static const char *
 DeviceToTypeString(unsigned device)
@@ -115,49 +112,37 @@ ParseLine(Directory &directory, const char *line)
 }
 
 static Directory *
-directory_load_subdir(TextFile &file, Directory &parent, const char *name,
-		      Error &error)
+directory_load_subdir(TextFile &file, Directory &parent, const char *name)
 {
-	bool success;
-
-	if (parent.FindChild(name) != nullptr) {
-		error.Format(directory_domain,
-			     "Duplicate subdirectory '%s'", name);
-		return nullptr;
-	}
+	if (parent.FindChild(name) != nullptr)
+		throw FormatRuntimeError("Duplicate subdirectory '%s'", name);
 
 	Directory *directory = parent.CreateChild(name);
 
-	while (true) {
-		const char *line = file.ReadLine();
-		if (line == nullptr) {
-			error.Set(directory_domain, "Unexpected end of file");
-			directory->Delete();
-			return nullptr;
-		}
+	try {
+		while (true) {
+			const char *line = file.ReadLine();
+			if (line == nullptr)
+				throw std::runtime_error("Unexpected end of file");
 
-		if (StringStartsWith(line, DIRECTORY_BEGIN))
-			break;
+			if (StringStartsWith(line, DIRECTORY_BEGIN))
+				break;
 
-		if (!ParseLine(*directory, line)) {
-			error.Format(directory_domain,
-				     "Malformed line: %s", line);
-			directory->Delete();
-			return nullptr;
+			if (!ParseLine(*directory, line))
+				throw FormatRuntimeError("Malformed line: %s", line);
 		}
-	}
 
-	success = directory_load(file, *directory, error);
-	if (!success) {
+		directory_load(file, *directory);
+	} catch (...) {
 		directory->Delete();
-		return nullptr;
+		throw;
 	}
 
 	return directory;
 }
 
-bool
-directory_load(TextFile &file, Directory &directory, Error &error)
+void
+directory_load(TextFile &file, Directory &directory)
 {
 	const char *line;
 
@@ -165,38 +150,23 @@ directory_load(TextFile &file, Directory &directory, Error &error)
 	       !StringStartsWith(line, DIRECTORY_END)) {
 		const char *p;
 		if ((p = StringAfterPrefix(line, DIRECTORY_DIR))) {
-			Directory *subdir =
-				directory_load_subdir(file, directory,
-						      p, error);
-			if (subdir == nullptr)
-				return false;
+			directory_load_subdir(file, directory, p);
 		} else if ((p = StringAfterPrefix(line, SONG_BEGIN))) {
 			const char *name = p;
 
-			if (directory.FindSong(name) != nullptr) {
-				error.Format(directory_domain,
-					     "Duplicate song '%s'", name);
-				return false;
-			}
+			if (directory.FindSong(name) != nullptr)
+				throw FormatRuntimeError("Duplicate song '%s'", name);
 
-			DetachedSong *song = song_load(file, name, error);
-			if (song == nullptr)
-				return false;
+			DetachedSong *song = song_load(file, name);
 
 			directory.AddSong(Song::NewFrom(std::move(*song),
 							directory));
 			delete song;
 		} else if ((p = StringAfterPrefix(line, PLAYLIST_META_BEGIN))) {
 			const char *name = p;
-			if (!playlist_metadata_load(file, directory.playlists,
-						    name, error))
-				return false;
+			playlist_metadata_load(file, directory.playlists, name);
 		} else {
-			error.Format(directory_domain,
-				     "Malformed line: %s", line);
-			return false;
+			throw FormatRuntimeError("Malformed line: %s", line);
 		}
 	}
-
-	return true;
 }

src/db/plugins/simple/DirectorySave.hxx

@@ -28,7 +28,10 @@ class Error;
 void
 directory_save(BufferedOutputStream &os, const Directory &directory);
 
-bool
-directory_load(TextFile &file, Directory &directory, Error &error);
+/**
+ * Throws #std::runtime_error on error.
+ */
+void
+directory_load(TextFile &file, Directory &directory);
 
 #endif

src/db/plugins/simple/SimpleDatabasePlugin.cxx

@@ -142,22 +142,19 @@ SimpleDatabase::Check() const
 #endif
 }
 
-bool
-SimpleDatabase::Load(Error &error)
+void
+SimpleDatabase::Load()
 {
 	assert(!path.IsNull());
 	assert(root != nullptr);
 
 	TextFile file(path);
 
-	if (!db_load_internal(file, *root, error))
-		return false;
+	db_load_internal(file, *root);
 
 	FileInfo fi;
 	if (GetFileInfo(path, fi))
 		mtime = fi.GetModificationTime();
-
-	return true;
 }
 
 void
@@ -173,16 +170,7 @@ SimpleDatabase::Open()
 #endif
 
 	try {
-		Error error2;
-		if (!Load(error2)) {
-			LogError(error2);
-
-			delete root;
-
-			Check();
-
-			root = Directory::NewRoot();
-		}
+		Load();
 	} catch (const std::exception &e) {
 		LogError(e);
 

src/db/plugins/simple/SimpleDatabasePlugin.hxx

@@ -136,7 +136,10 @@ private:
 
 	void Check() const;
 
-	bool Load(Error &error);
+	/**
+	 * Throws #std::runtime_error on error.
+	 */
+	void Load();
 
 	Database *LockUmountSteal(const char *uri);
 };

src/queue/QueueSave.cxx

@@ -27,7 +27,6 @@
 #include "fs/io/TextFile.hxx"
 #include "fs/io/BufferedOutputStream.hxx"
 #include "util/StringCompare.hxx"
-#include "util/Error.hxx"
 #include "Log.hxx"
 
 #include <stdlib.h>
@@ -95,10 +94,10 @@ queue_load_song(TextFile &file, const SongLoader &loader,
 	if ((p = StringAfterPrefix(line, SONG_BEGIN))) {
 		const char *uri = p;
 
-		Error error;
-		song = song_load(file, uri, error);
-		if (song == nullptr) {
-			LogError(error);
+		try {
+			song = song_load(file, uri);
+		} catch (const std::runtime_error &e) {
+			LogError(e);
 			return;
 		}
 	} else {