database: don't allow uri==NULL

Add nonnull attributes and fix all callers.

src/command.c

@@ -963,7 +963,7 @@ handle_find(struct client *client, int argc, char *argv[])
 	}
 
 	GError *error = NULL;
-	enum command_return ret = findSongsIn(client, NULL, list, &error)
+	enum command_return ret = findSongsIn(client, "", list, &error)
 		? COMMAND_RETURN_OK
 		: print_error(client, error);
 
@@ -987,7 +987,7 @@ handle_findadd(struct client *client, int argc, char *argv[])
 
     GError *error = NULL;
     enum command_return ret =
-	    findAddIn(client->player_control, NULL, list, &error)
+	    findAddIn(client->player_control, "", list, &error)
 	    ? COMMAND_RETURN_OK
 	    : print_error(client, error);
 
@@ -1011,7 +1011,7 @@ handle_search(struct client *client, int argc, char *argv[])
 	}
 
 	GError *error = NULL;
-	enum command_return ret = searchForSongsIn(client, NULL, list, &error)
+	enum command_return ret = searchForSongsIn(client, "", list, &error)
 		? COMMAND_RETURN_OK
 		: print_error(client, error);
 
@@ -1036,7 +1036,7 @@ handle_count(struct client *client, int argc, char *argv[])
 
 	GError *error = NULL;
 	enum command_return ret =
-		searchStatsForSongsIn(client, NULL, list, &error)
+		searchStatsForSongsIn(client, "", list, &error)
 		? COMMAND_RETURN_OK
 		: print_error(client, error);
 
@@ -1266,7 +1266,7 @@ handle_prioid(struct client *client, int argc, char *argv[])
 static enum command_return
 handle_listall(struct client *client, G_GNUC_UNUSED int argc, char *argv[])
 {
-	char *directory = NULL;
+	const char *directory = "";
 
 	if (argc == 2)
 		directory = argv[1];
@@ -1537,7 +1537,7 @@ handle_seekid(struct client *client, G_GNUC_UNUSED int argc, char *argv[])
 static enum command_return
 handle_listallinfo(struct client *client, G_GNUC_UNUSED int argc, char *argv[])
 {
-	char *directory = NULL;
+	const char *directory = "";
 
 	if (argc == 2)
 		directory = argv[1];

src/database.h

@@ -20,6 +20,8 @@
 #ifndef MPD_DATABASE_H
 #define MPD_DATABASE_H
 
+#include "gcc.h"
+
 #include <glib.h>
 
 #include <sys/time.h>
@@ -47,12 +49,15 @@ db_finish(void);
 struct directory *
 db_get_root(void);
 
+gcc_nonnull(1)
 struct directory *
 db_get_directory(const char *name);
 
+gcc_nonnull(1)
 struct song *
 db_get_song(const char *file);
 
+gcc_nonnull(1,2)
 bool
 db_walk(const char *uri,
 	const struct db_visitor *visitor, void *ctx,

src/dbUtils.h

@@ -20,23 +20,26 @@
 #ifndef MPD_DB_UTILS_H
 #define MPD_DB_UTILS_H
 
+#include "gcc.h"
+
 #include <glib.h>
 #include <stdbool.h>
 
 struct locate_item_list;
 struct player_control;
 
+gcc_nonnull(1,2)
 bool
 addAllIn(struct player_control *pc, const char *uri, GError **error_r);
 
+gcc_nonnull(1,2)
 bool
 addAllInToStoredPlaylist(const char *uri_utf8, const char *path_utf8,
 			 GError **error_r);
 
+gcc_nonnull(1,2,3)
 bool
 findAddIn(struct player_control *pc, const char *name,
 	  const struct locate_item_list *criteria, GError **error_r);
 
-unsigned long sumSongTimesIn(const char *name);
-
 #endif

src/db_print.c

@@ -286,7 +286,7 @@ listAllUniqueTags(struct client *client, int type,
 		data.set = strset_new();
 	}
 
-	if (!db_walk(NULL, &unique_tags_visitor, &data, error_r)) {
+	if (!db_walk("", &unique_tags_visitor, &data, error_r)) {
 		freeListCommandItem(item);
 		return false;
 	}

src/db_print.h

@@ -20,6 +20,8 @@
 #ifndef MPD_DB_PRINT_H
 #define MPD_DB_PRINT_H
 
+#include "gcc.h"
+
 #include <glib.h>
 #include <stdbool.h>
 
@@ -27,28 +29,34 @@ struct client;
 struct locate_item_list;
 struct db_visitor;
 
+gcc_nonnull(1,2)
 bool
 printAllIn(struct client *client, const char *uri_utf8, GError **error_r);
 
+gcc_nonnull(1,2)
 bool
 printInfoForAllIn(struct client *client, const char *uri_utf8,
 		  GError **error_r);
 
+gcc_nonnull(1,2,3)
 bool
 searchForSongsIn(struct client *client, const char *name,
 		 const struct locate_item_list *criteria,
 		 GError **error_r);
 
+gcc_nonnull(1,2,3)
 bool
 findSongsIn(struct client *client, const char *name,
 	    const struct locate_item_list *criteria,
 	    GError **error_r);
 
+gcc_nonnull(1,2,3)
 bool
 searchStatsForSongsIn(struct client *client, const char *name,
 		      const struct locate_item_list *criteria,
 		      GError **error_r);
 
+gcc_nonnull(1,3)
 bool
 listAllUniqueTags(struct client *client, int type,
 		  const struct locate_item_list *criteria,

src/locate.h

@@ -20,6 +20,8 @@
 #ifndef MPD_LOCATE_H
 #define MPD_LOCATE_H
 
+#include "gcc.h"
+
 #include <stdint.h>
 #include <stdbool.h>
 
@@ -57,6 +59,7 @@ struct locate_item_list *
 locate_item_list_new(unsigned length);
 
 /* return number of items or -1 on error */
+gcc_nonnull(1)
 struct locate_item_list *
 locate_item_list_parse(char *argv[], int argc);
 
@@ -64,19 +67,24 @@ locate_item_list_parse(char *argv[], int argc);
  * Duplicate the struct locate_item_list object and convert all
  * needles with g_utf8_casefold().
  */
+gcc_nonnull(1)
 struct locate_item_list *
 locate_item_list_casefold(const struct locate_item_list *list);
 
+gcc_nonnull(1)
 void
 locate_item_list_free(struct locate_item_list *list);
 
+gcc_nonnull(1)
 void
 locate_item_free(struct locate_item *item);
 
+gcc_nonnull(1,2)
 bool
 locate_song_search(const struct song *song,
 		   const struct locate_item_list *criteria);
 
+gcc_nonnull(1,2)
 bool
 locate_song_match(const struct song *song,
 		   const struct locate_item_list *criteria);

src/stats.c

@@ -98,7 +98,7 @@ void stats_update(void)
 	data.artists = strset_new();
 	data.albums = strset_new();
 
-	db_walk(NULL, &collect_stats_visitor, &data, NULL);
+	db_walk("", &collect_stats_visitor, &data, NULL);
 
 	stats.artist_count = strset_size(data.artists);
 	stats.album_count = strset_size(data.albums);