*: add "noexcept" to many, many function prototypes

This eliminates some overhead, because the compiler doesn't need to
consider these functions throwing.

src/db/DatabaseLock.hxx

@@ -45,7 +45,7 @@ extern ThreadId db_mutex_holder;
  */
 gcc_pure
 static inline bool
-holding_db_lock(void)
+holding_db_lock() noexcept
 {
 	return db_mutex_holder.IsInside();
 }

src/db/LightSong.cxx

@@ -21,7 +21,7 @@
 #include "tag/Tag.hxx"
 
 SignedSongTime
-LightSong::GetDuration() const
+LightSong::GetDuration() const noexcept
 {
 	SongTime a = start_time, b = end_time;
 	if (!b.IsPositive()) {

src/db/LightSong.hxx

@@ -76,7 +76,7 @@ struct LightSong {
 	SongTime end_time;
 
 	gcc_pure
-	std::string GetURI() const {
+	std::string GetURI() const noexcept {
 		if (directory == nullptr)
 			return std::string(uri);
 
@@ -87,7 +87,7 @@ struct LightSong {
 	}
 
 	gcc_pure
-	SignedSongTime GetDuration() const;
+	SignedSongTime GetDuration() const noexcept;
 };
 
 #endif

src/db/PlaylistVector.cxx

@@ -26,7 +26,7 @@
 #include <assert.h>
 
 PlaylistVector::iterator
-PlaylistVector::find(const char *name)
+PlaylistVector::find(const char *name) noexcept
 {
 	assert(holding_db_lock());
 	assert(name != nullptr);

src/db/PlaylistVector.hxx

@@ -31,7 +31,7 @@ protected:
 	 * Caller must lock the #db_mutex.
 	 */
 	gcc_pure
-	iterator find(const char *name);
+	iterator find(const char *name) noexcept;
 
 public:
 	using std::list<PlaylistInfo>::empty;

src/db/Registry.cxx

@@ -38,7 +38,7 @@ const DatabasePlugin *const database_plugins[] = {
 };
 
 const DatabasePlugin *
-GetDatabasePluginByName(const char *name)
+GetDatabasePluginByName(const char *name) noexcept
 {
 	for (auto i = database_plugins; *i != nullptr; ++i)
 		if (strcmp((*i)->name, name) == 0)

src/db/Registry.hxx

@@ -32,6 +32,6 @@ extern const DatabasePlugin *const database_plugins[];
 
 gcc_pure
 const DatabasePlugin *
-GetDatabasePluginByName(const char *name);
+GetDatabasePluginByName(const char *name) noexcept;
 
 #endif

src/db/Selection.cxx

@@ -34,19 +34,19 @@ DatabaseSelection::DatabaseSelection(const char *_uri, bool _recursive,
 }
 
 bool
-DatabaseSelection::IsEmpty() const
+DatabaseSelection::IsEmpty() const noexcept
 {
 	return uri.empty() && (filter == nullptr || filter->IsEmpty());
 }
 
 bool
-DatabaseSelection::HasOtherThanBase() const
+DatabaseSelection::HasOtherThanBase() const noexcept
 {
 	return filter != nullptr && filter->HasOtherThanBase();
 }
 
 bool
-DatabaseSelection::Match(const LightSong &song) const
+DatabaseSelection::Match(const LightSong &song) const noexcept
 {
 	return filter == nullptr || filter->Match(song);
 }

src/db/Selection.hxx

@@ -45,16 +45,16 @@ struct DatabaseSelection {
 			  const SongFilter *_filter=nullptr);
 
 	gcc_pure
-	bool IsEmpty() const;
+	bool IsEmpty() const noexcept;
 
 	/**
 	 * Does this selection contain constraints other than "base"?
 	 */
 	gcc_pure
-	bool HasOtherThanBase() const;
+	bool HasOtherThanBase() const noexcept;
 
 	gcc_pure
-	bool Match(const LightSong &song) const;
+	bool Match(const LightSong &song) const noexcept;
 };
 
 #endif

src/db/plugins/ProxyDatabasePlugin.cxx

@@ -216,7 +216,7 @@ ProxySong::ProxySong(const mpd_song *song)
 
 gcc_const
 static enum mpd_tag_type
-Convert(TagType tag_type)
+Convert(TagType tag_type) noexcept
 {
 	for (auto i = &tag_table[0]; i->d != TAG_NUM_OF_ITEM_TYPES; ++i)
 		if (i->d == tag_type)
@@ -574,7 +574,7 @@ Visit(struct mpd_connection *connection,
 
 gcc_pure
 static bool
-Match(const SongFilter *filter, const LightSong &song)
+Match(const SongFilter *filter, const LightSong &song) noexcept
 {
 	return filter == nullptr || filter->Match(song);
 }
@@ -717,7 +717,7 @@ SearchSongs(struct mpd_connection *connection,
  */
 gcc_pure
 static bool
-ServerSupportsSearchBase(const struct mpd_connection *connection)
+ServerSupportsSearchBase(const struct mpd_connection *connection) noexcept
 {
 #if LIBMPDCLIENT_CHECK_VERSION(2,9,0)
 	return mpd_connection_cmp_server_version(connection, 0, 18, 0) >= 0;

src/db/plugins/simple/Directory.cxx

@@ -65,7 +65,7 @@ Directory::Delete()
 }
 
 const char *
-Directory::GetName() const
+Directory::GetName() const noexcept
 {
 	assert(!IsRoot());
 
@@ -89,7 +89,7 @@ Directory::CreateChild(const char *name_utf8)
 }
 
 const Directory *
-Directory::FindChild(const char *name) const
+Directory::FindChild(const char *name) const noexcept
 {
 	assert(holding_db_lock());
 
@@ -101,7 +101,7 @@ Directory::FindChild(const char *name) const
 }
 
 void
-Directory::PruneEmpty()
+Directory::PruneEmpty() noexcept
 {
 	assert(holding_db_lock());
 
@@ -118,7 +118,7 @@ Directory::PruneEmpty()
 }
 
 Directory::LookupResult
-Directory::LookupDirectory(const char *uri)
+Directory::LookupDirectory(const char *uri) noexcept
 {
 	assert(holding_db_lock());
 	assert(uri != nullptr);
@@ -173,7 +173,7 @@ Directory::AddSong(Song *song)
 }
 
 void
-Directory::RemoveSong(Song *song)
+Directory::RemoveSong(Song *song) noexcept
 {
 	assert(holding_db_lock());
 	assert(song != nullptr);
@@ -183,7 +183,7 @@ Directory::RemoveSong(Song *song)
 }
 
 const Song *
-Directory::FindSong(const char *name_utf8) const
+Directory::FindSong(const char *name_utf8) const noexcept
 {
 	assert(holding_db_lock());
 	assert(name_utf8 != nullptr);
@@ -200,13 +200,13 @@ Directory::FindSong(const char *name_utf8) const
 
 gcc_pure
 static bool
-directory_cmp(const Directory &a, const Directory &b)
+directory_cmp(const Directory &a, const Directory &b) noexcept
 {
 	return IcuCollate(a.path.c_str(), b.path.c_str()) < 0;
 }
 
 void
-Directory::Sort()
+Directory::Sort() noexcept
 {
 	assert(holding_db_lock());
 
@@ -261,7 +261,7 @@ Directory::Walk(bool recursive, const SongFilter *filter,
 }
 
 LightDirectory
-Directory::Export() const
+Directory::Export() const noexcept
 {
 	return LightDirectory(GetPath(), mtime);
 }

src/db/plugins/simple/Directory.hxx

@@ -134,10 +134,10 @@ public:
 	 * Caller must lock the #db_mutex.
 	 */
 	gcc_pure
-	const Directory *FindChild(const char *name) const;
+	const Directory *FindChild(const char *name) const noexcept;
 
 	gcc_pure
-	Directory *FindChild(const char *name) {
+	Directory *FindChild(const char *name) noexcept {
 		const Directory *cthis = this;
 		return const_cast<Directory *>(cthis->FindChild(name));
 	}
@@ -177,10 +177,10 @@ public:
 	 * @return the Directory, or nullptr if none was found
 	 */
 	gcc_pure
-	LookupResult LookupDirectory(const char *uri);
+	LookupResult LookupDirectory(const char *uri) noexcept;
 
 	gcc_pure
-	bool IsEmpty() const {
+	bool IsEmpty() const noexcept {
 		return children.empty() &&
 			songs.empty() &&
 			playlists.empty();
@@ -195,13 +195,13 @@ public:
 	 * Returns the base name of the directory.
 	 */
 	gcc_pure
-	const char *GetName() const;
+	const char *GetName() const noexcept;
 
 	/**
 	 * Is this the root directory of the music database?
 	 */
 	gcc_pure
-	bool IsRoot() const {
+	bool IsRoot() const noexcept {
 		return parent == nullptr;
 	}
 
@@ -229,10 +229,10 @@ public:
 	 * Caller must lock the #db_mutex.
 	 */
 	gcc_pure
-	const Song *FindSong(const char *name_utf8) const;
+	const Song *FindSong(const char *name_utf8) const noexcept;
 
 	gcc_pure
-	Song *FindSong(const char *name_utf8) {
+	Song *FindSong(const char *name_utf8) noexcept {
 		const Directory *cthis = this;
 		return const_cast<Song *>(cthis->FindSong(name_utf8));
 	}
@@ -248,19 +248,19 @@ public:
 	 * invalidates the song object, because the "parent" attribute becomes
 	 * stale), but does not free it.
 	 */
-	void RemoveSong(Song *song);
+	void RemoveSong(Song *song) noexcept;
 
 	/**
 	 * Caller must lock the #db_mutex.
 	 */
-	void PruneEmpty();
+	void PruneEmpty() noexcept;
 
 	/**
 	 * Sort all directory entries recursively.
 	 *
 	 * Caller must lock the #db_mutex.
 	 */
-	void Sort();
+	void Sort() noexcept;
 
 	/**
 	 * Caller must lock #db_mutex.
@@ -270,7 +270,7 @@ public:
 		  VisitPlaylist visit_playlist) const;
 
 	gcc_pure
-	LightDirectory Export() const;
+	LightDirectory Export() const noexcept;
 };
 
 #endif

src/db/plugins/simple/DirectorySave.cxx

@@ -40,7 +40,7 @@
 
 gcc_const
 static const char *
-DeviceToTypeString(unsigned device)
+DeviceToTypeString(unsigned device) noexcept
 {
 	switch (device) {
 	case DEVICE_INARCHIVE:
@@ -56,7 +56,7 @@ DeviceToTypeString(unsigned device)
 
 gcc_pure
 static unsigned
-ParseTypeString(const char *type)
+ParseTypeString(const char *type) noexcept
 {
 	if (strcmp(type, "archive") == 0)
 		return DEVICE_INARCHIVE;

src/db/plugins/simple/Song.cxx

@@ -77,7 +77,7 @@ Song::Free()
 }
 
 std::string
-Song::GetURI() const
+Song::GetURI() const noexcept
 {
 	assert(*uri);
 
@@ -96,7 +96,7 @@ Song::GetURI() const
 }
 
 LightSong
-Song::Export() const
+Song::Export() const noexcept
 {
 	LightSong dest;
 	dest.directory = parent->IsRoot()

src/db/plugins/simple/Song.hxx

@@ -123,10 +123,10 @@ struct Song {
 	 * location within the music directory.
 	 */
 	gcc_pure
-	std::string GetURI() const;
+	std::string GetURI() const noexcept;
 
 	gcc_pure
-	LightSong Export() const;
+	LightSong Export() const noexcept;
 };
 
 typedef boost::intrusive::list<Song,

src/db/plugins/simple/SongSort.cxx

@@ -26,7 +26,7 @@
 #include <stdlib.h>
 
 static int
-compare_utf8_string(const char *a, const char *b)
+compare_utf8_string(const char *a, const char *b) noexcept
 {
 	if (a == nullptr)
 		return b == nullptr ? 0 : -1;
@@ -42,8 +42,7 @@ compare_utf8_string(const char *a, const char *b)
  * nullptr.
  */
 static int
-compare_string_tag_item(const Tag &a, const Tag &b,
-			TagType type)
+compare_string_tag_item(const Tag &a, const Tag &b, TagType type) noexcept
 {
 	return compare_utf8_string(a.GetValue(type),
 				   b.GetValue(type));
@@ -54,7 +53,7 @@ compare_string_tag_item(const Tag &a, const Tag &b,
  * (e.g. disc or track number).  Either one may be nullptr.
  */
 static int
-compare_number_string(const char *a, const char *b)
+compare_number_string(const char *a, const char *b) noexcept
 {
 	long ai = a == nullptr ? 0 : strtol(a, nullptr, 10);
 	long bi = b == nullptr ? 0 : strtol(b, nullptr, 10);
@@ -69,7 +68,7 @@ compare_number_string(const char *a, const char *b)
 }
 
 static int
-compare_tag_item(const Tag &a, const Tag &b, TagType type)
+compare_tag_item(const Tag &a, const Tag &b, TagType type) noexcept
 {
 	return compare_number_string(a.GetValue(type),
 				     b.GetValue(type));
@@ -78,7 +77,7 @@ compare_tag_item(const Tag &a, const Tag &b, TagType type)
 /* Only used for sorting/searchin a songvec, not general purpose compares */
 gcc_pure
 static bool
-song_cmp(const Song &a, const Song &b)
+song_cmp(const Song &a, const Song &b) noexcept
 {
 	int ret;
 
@@ -102,7 +101,7 @@ song_cmp(const Song &a, const Song &b)
 }
 
 void
-song_list_sort(SongList &songs)
+song_list_sort(SongList &songs) noexcept
 {
 	songs.sort(song_cmp);
 }

src/db/plugins/simple/SongSort.hxx

@@ -23,6 +23,6 @@
 #include "Song.hxx"
 
 void
-song_list_sort(SongList &songs);
+song_list_sort(SongList &songs) noexcept;
 
 #endif

src/db/plugins/upnp/Directory.cxx

@@ -39,7 +39,7 @@ UPnPDirContent::~UPnPDirContent()
 
 gcc_pure
 static UPnPDirObject::ItemClass
-ParseItemClass(StringView name)
+ParseItemClass(StringView name) noexcept
 {
 	if (name.EqualsLiteral("object.item.audioItem.musicTrack"))
 		return UPnPDirObject::ItemClass::MUSIC;
@@ -51,7 +51,7 @@ ParseItemClass(StringView name)
 
 gcc_pure
 static SignedSongTime
-ParseDuration(const char *duration)
+ParseDuration(const char *duration) noexcept
 {
 	char *endptr;
 
@@ -81,7 +81,7 @@ ParseDuration(const char *duration)
  */
 gcc_pure
 static std::string &&
-TitleToPathSegment(std::string &&s)
+TitleToPathSegment(std::string &&s) noexcept
 {
 	std::replace(s.begin(), s.end(), '/', '_');
 	return std::move(s);

src/db/plugins/upnp/Directory.hxx

@@ -40,7 +40,7 @@ public:
 	~UPnPDirContent();
 
 	gcc_pure
-	UPnPDirObject *FindObject(const char *name) {
+	UPnPDirObject *FindObject(const char *name) noexcept {
 		for (auto &o : objects)
 			if (o.name == name)
 				return &o;

src/db/update/InotifyQueue.cxx

@@ -56,7 +56,7 @@ InotifyQueue::OnTimeout()
 
 gcc_pure
 static bool
-path_in(const char *path, const char *possible_parent)
+path_in(const char *path, const char *possible_parent) noexcept
 {
 	if (StringIsEmpty(path))
 		return true;

src/db/update/InotifyUpdate.cxx

@@ -62,10 +62,10 @@ struct WatchDirectory {
 	WatchDirectory &operator=(const WatchDirectory &) = delete;
 
 	gcc_pure
-	unsigned GetDepth() const;
+	unsigned GetDepth() const noexcept;
 
 	gcc_pure
-	AllocatedPath GetUriFS() const;
+	AllocatedPath GetUriFS() const noexcept;
 };
 
 static InotifySource *inotify_source;
@@ -132,7 +132,7 @@ remove_watch_directory(WatchDirectory *directory)
 }
 
 AllocatedPath
-WatchDirectory::GetUriFS() const
+WatchDirectory::GetUriFS() const noexcept
 {
 	if (parent == nullptr)
 		return AllocatedPath::Null();
@@ -225,7 +225,7 @@ recursive_watch_subdirectories(WatchDirectory *directory,
 
 gcc_pure
 unsigned
-WatchDirectory::GetDepth() const
+WatchDirectory::GetDepth() const noexcept
 {
 	const WatchDirectory *d = this;
 	unsigned depth = 0;
@@ -331,7 +331,7 @@ mpd_inotify_init(EventLoop &loop, Storage &storage, UpdateService &update,
 }
 
 void
-mpd_inotify_finish(void)
+mpd_inotify_finish(void) noexcept
 {
 	if (inotify_source == nullptr)
 		return;

src/db/update/InotifyUpdate.hxx

@@ -32,6 +32,6 @@ mpd_inotify_init(EventLoop &loop, Storage &storage, UpdateService &update,
 		 unsigned max_depth);
 
 void
-mpd_inotify_finish();
+mpd_inotify_finish() noexcept;
 
 #endif

src/db/update/UpdateIO.cxx

@@ -32,7 +32,7 @@
 #include <errno.h>
 
 bool
-GetInfo(Storage &storage, const char *uri_utf8, StorageFileInfo &info)
+GetInfo(Storage &storage, const char *uri_utf8, StorageFileInfo &info) noexcept
 try {
 	info = storage.GetInfo(uri_utf8, true);
 	return true;
@@ -42,7 +42,7 @@ try {
 }
 
 bool
-GetInfo(StorageDirectoryReader &reader, StorageFileInfo &info)
+GetInfo(StorageDirectoryReader &reader, StorageFileInfo &info) noexcept
 try {
 	info = reader.GetInfo(true);
 	return true;
@@ -52,7 +52,7 @@ try {
 }
 
 bool
-DirectoryExists(Storage &storage, const Directory &directory)
+DirectoryExists(Storage &storage, const Directory &directory) noexcept
 {
 	StorageFileInfo info;
 
@@ -79,7 +79,7 @@ GetDirectoryChildInfo(Storage &storage, const Directory &directory,
 
 bool
 directory_child_is_regular(Storage &storage, const Directory &directory,
-			   const char *name_utf8)
+			   const char *name_utf8) noexcept
 try {
 	return GetDirectoryChildInfo(storage, directory, name_utf8)
 		.IsRegular();
@@ -89,7 +89,7 @@ try {
 
 bool
 directory_child_access(Storage &storage, const Directory &directory,
-		       const char *name, int mode)
+		       const char *name, int mode) noexcept
 {
 #ifdef WIN32
 	/* CheckAccess() is useless on WIN32 */

src/db/update/UpdateIO.hxx

@@ -33,23 +33,23 @@ class StorageDirectoryReader;
  * returning them.
  */
 bool
-GetInfo(Storage &storage, const char *uri_utf8, StorageFileInfo &info);
+GetInfo(Storage &storage, const char *uri_utf8, StorageFileInfo &info) noexcept;
 
 /**
  * Wrapper for LocalDirectoryReader::GetInfo() that logs errors
  * instead of returning them.
  */
 bool
-GetInfo(StorageDirectoryReader &reader, StorageFileInfo &info);
+GetInfo(StorageDirectoryReader &reader, StorageFileInfo &info) noexcept;
 
 gcc_pure
 bool
-DirectoryExists(Storage &storage, const Directory &directory);
+DirectoryExists(Storage &storage, const Directory &directory) noexcept;
 
 gcc_pure
 bool
 directory_child_is_regular(Storage &storage, const Directory &directory,
-			   const char *name_utf8);
+			   const char *name_utf8) noexcept;
 
 /**
  * Checks if the given permissions on the mapped file are given.
@@ -57,6 +57,6 @@ directory_child_is_regular(Storage &storage, const Directory &directory,
 gcc_pure
 bool
 directory_child_access(Storage &storage, const Directory &directory,
-		       const char *name, int mode);
+		       const char *name, int mode) noexcept;
 
 #endif

src/db/update/Walk.cxx

@@ -248,7 +248,7 @@ try {
 /* we don't look at "." / ".." nor files with newlines in their name */
 gcc_pure
 static bool
-skip_path(const char *name_utf8)
+skip_path(const char *name_utf8) noexcept
 {
 	return strchr(name_utf8, '\n') != nullptr;
 }
@@ -256,7 +256,7 @@ skip_path(const char *name_utf8)
 gcc_pure
 bool
 UpdateWalk::SkipSymlink(const Directory *directory,
-			const char *utf8_name) const
+			const char *utf8_name) const noexcept
 {
 #ifndef WIN32
 	const auto path_fs = storage.MapChildFS(directory->GetPath(),

src/db/update/Walk.hxx

@@ -78,7 +78,7 @@ public:
 private:
 	gcc_pure
 	bool SkipSymlink(const Directory *directory,
-			 const char *utf8_name) const;
+			 const char *utf8_name) const noexcept;
 
 	void RemoveExcludedFromDirectory(Directory &directory,
 					 const ExcludeList &exclude_list);