util/StringCompare: add StringIsEmpty()

src/Mapper.cxx

@@ -27,6 +27,7 @@
 #include "fs/Traits.hxx"
 #include "fs/Charset.hxx"
 #include "fs/CheckFile.hxx"
+#include "util/StringCompare.hxx"
 
 #ifdef ENABLE_DATABASE
 #include "storage/StorageInterface.hxx"
@@ -98,7 +99,7 @@ map_fs_to_utf8(Path path_fs)
 			return std::string();
 
 		auto relative = music_dir_fs.Relative(path_fs);
-		if (relative == nullptr || *relative == 0)
+		if (relative == nullptr || StringIsEmpty(relative))
 			return std::string();
 
 		path_fs = Path::FromFS(relative);

src/PlaylistFile.cxx

@@ -70,7 +70,7 @@ spl_global_init(void)
 bool
 spl_valid_name(const char *name_utf8)
 {
-	if (*name_utf8 == 0)
+	if (StringIsEmpty(name_utf8))
 		/* empty name not allowed */
 		return false;
 

src/db/update/Archive.cxx

@@ -31,6 +31,7 @@
 #include "archive/ArchiveFile.hxx"
 #include "archive/ArchiveVisitor.hxx"
 #include "util/Error.hxx"
+#include "util/StringCompare.hxx"
 #include "Log.hxx"
 
 #include <string>
@@ -54,7 +55,7 @@ UpdateWalk::UpdateArchiveTree(Directory &directory, const char *name)
 		//create directories first
 		UpdateArchiveTree(*subdir, tmp + 1);
 	} else {
-		if (strlen(name) == 0) {
+		if (StringIsEmpty(name)) {
 			LogWarning(update_domain,
 				   "archive returned directory only");
 			return;

src/db/update/InotifyQueue.cxx

@@ -22,6 +22,7 @@
 #include "InotifyDomain.hxx"
 #include "Service.hxx"
 #include "Log.hxx"
+#include "util/StringCompare.hxx"
 
 #include <string.h>
 
@@ -59,7 +60,7 @@ path_in(const char *path, const char *possible_parent)
 {
 	size_t length = strlen(possible_parent);
 
-	return path[0] == 0 ||
+	return StringIsEmpty(path) ||
 		(memcmp(possible_parent, path, length) == 0 &&
 		 (path[length] == 0 || path[length] == '/'));
 }

src/db/update/Walk.cxx

@@ -38,6 +38,7 @@
 #include "fs/Charset.hxx"
 #include "storage/FileInfo.hxx"
 #include "util/Alloc.hxx"
+#include "util/StringCompare.hxx"
 #include "util/UriUtil.hxx"
 #include "util/Error.hxx"
 #include "Log.hxx"
@@ -435,7 +436,7 @@ UpdateWalk::DirectoryMakeUriParentChecked(Directory &root, const char *uri)
 	while ((slash = strchr(name_utf8, '/')) != nullptr) {
 		*slash = 0;
 
-		if (*name_utf8 == 0)
+		if (StringIsEmpty(name_utf8))
 			continue;
 
 		directory = DirectoryMakeChildChecked(*directory,

src/input/plugins/AlsaInputPlugin.cxx

@@ -164,7 +164,7 @@ AlsaInputStream::Create(const char *uri, Mutex &mutex, Cond &cond,
 		return nullptr;
 
 	const char *device = uri + strlen(scheme);
-	if (strlen(device) == 0)
+	if (*device == 0)
 		device = default_device;
 
 	/* placeholders - eventually user-requested audio format will

src/sticker/StickerDatabase.cxx

@@ -25,6 +25,7 @@
 #include "Idle.hxx"
 #include "util/Error.hxx"
 #include "util/Macros.hxx"
+#include "util/StringCompare.hxx"
 
 #include <string>
 #include <map>
@@ -178,7 +179,7 @@ sticker_load_value(const char *type, const char *uri, const char *name,
 	assert(uri != nullptr);
 	assert(name != nullptr);
 
-	if (*name == 0)
+	if (StringIsEmpty(name))
 		return std::string();
 
 	if (!BindAll(error, stmt, type, uri, name))
@@ -287,7 +288,7 @@ sticker_store_value(const char *type, const char *uri,
 	assert(name != nullptr);
 	assert(value != nullptr);
 
-	if (*name == 0)
+	if (StringIsEmpty(name))
 		return false;
 
 	return sticker_update_value(type, uri, name, value, error) ||

src/storage/CompositeStorage.cxx

@@ -23,6 +23,7 @@
 #include "fs/AllocatedPath.hxx"
 #include "util/Error.hxx"
 #include "util/Domain.hxx"
+#include "util/StringCompare.hxx"
 
 #include <set>
 
@@ -164,7 +165,7 @@ CompositeStorage::Directory::Unmount()
 bool
 CompositeStorage::Directory::Unmount(const char *uri)
 {
-	if (*uri == 0)
+	if (StringIsEmpty(uri))
 		return Unmount();
 
 	const std::string name = NextSegment(uri);

src/storage/plugins/LocalStorage.cxx

@@ -22,10 +22,11 @@
 #include "storage/StoragePlugin.hxx"
 #include "storage/StorageInterface.hxx"
 #include "storage/FileInfo.hxx"
-#include "util/Error.hxx"
 #include "fs/FileInfo.hxx"
 #include "fs/AllocatedPath.hxx"
 #include "fs/DirectoryReader.hxx"
+#include "util/Error.hxx"
+#include "util/StringCompare.hxx"
 
 #include <string>
 
@@ -108,7 +109,7 @@ LocalStorage::MapUTF8(const char *uri_utf8) const
 {
 	assert(uri_utf8 != nullptr);
 
-	if (*uri_utf8 == 0)
+	if (StringIsEmpty(uri_utf8))
 		return base_utf8;
 
 	return PathTraitsUTF8::Build(base_utf8.c_str(), uri_utf8);
@@ -119,7 +120,7 @@ LocalStorage::MapFS(const char *uri_utf8, Error &error) const
 {
 	assert(uri_utf8 != nullptr);
 
-	if (*uri_utf8 == 0)
+	if (StringIsEmpty(uri_utf8))
 		return base_fs;
 
 	AllocatedPath path_fs = AllocatedPath::FromUTF8(uri_utf8, error);

src/storage/plugins/NfsStorage.cxx

@@ -30,13 +30,14 @@
 #include "lib/nfs/Connection.hxx"
 #include "lib/nfs/Glue.hxx"
 #include "fs/AllocatedPath.hxx"
-#include "util/Error.hxx"
 #include "thread/Mutex.hxx"
 #include "thread/Cond.hxx"
 #include "event/Loop.hxx"
 #include "event/Call.hxx"
 #include "event/DeferredMonitor.hxx"
 #include "event/TimeoutMonitor.hxx"
+#include "util/Error.hxx"
+#include "util/StringCompare.hxx"
 
 extern "C" {
 #include <nfsc/libnfs.h>
@@ -232,7 +233,7 @@ NfsStorage::MapUTF8(const char *uri_utf8) const
 {
 	assert(uri_utf8 != nullptr);
 
-	if (*uri_utf8 == 0)
+	if (StringIsEmpty(uri_utf8))
 		return base;
 
 	return PathTraitsUTF8::Build(base.c_str(), uri_utf8);

src/storage/plugins/SmbclientStorage.cxx

@@ -25,8 +25,9 @@
 #include "lib/smbclient/Init.hxx"
 #include "lib/smbclient/Mutex.hxx"
 #include "fs/Traits.hxx"
-#include "util/Error.hxx"
 #include "thread/Mutex.hxx"
+#include "util/Error.hxx"
+#include "util/StringCompare.hxx"
 
 #include <libsmbclient.h>
 
@@ -80,7 +81,7 @@ SmbclientStorage::MapUTF8(const char *uri_utf8) const
 {
 	assert(uri_utf8 != nullptr);
 
-	if (*uri_utf8 == 0)
+	if (StringIsEmpty(uri_utf8))
 		return base;
 
 	return PathTraitsUTF8::Build(base.c_str(), uri_utf8);

src/util/StringCompare.hxx

@@ -36,6 +36,12 @@
 #include "WStringCompare.hxx"
 #endif
 
+static inline bool
+StringIsEmpty(const char *string)
+{
+  return *string == 0;
+}
+
 gcc_pure
 bool
 StringStartsWith(const char *haystack, const char *needle);

src/util/WStringCompare.hxx

@@ -34,6 +34,12 @@
 
 #include <wchar.h>
 
+static inline bool
+StringIsEmpty(const wchar_t *string)
+{
+  return *string == 0;
+}
+
 gcc_pure
 bool
 StringStartsWith(const wchar_t *haystack, const wchar_t *needle);