Order orphans by path

It costs more cycles, but the SHA-1 they got implicitly ordered by
is pseudo-random.

initialize.sql

@@ -23,6 +23,7 @@ CREATE TABLE IF NOT EXISTS node(
 ) STRICT;
 
 CREATE INDEX IF NOT EXISTS node__sha1 ON node(sha1);
+CREATE INDEX IF NOT EXISTS node__parent ON node(parent);
 CREATE UNIQUE INDEX IF NOT EXISTS node__parent_name
 ON node(IFNULL(parent, 0), name);
 

main.go

@@ -94,10 +94,15 @@ func init() {
 }
 
 func openDB(directory string) error {
+	galleryDirectory = directory
+
 	var err error
 	db, err = sql.Open("sqlite3_custom", "file:"+filepath.Join(directory,
 		nameOfDB+"?_foreign_keys=1&_busy_timeout=1000"))
-	galleryDirectory = directory
+	if err != nil {
+		return err
+	}
+	_, err = db.Exec(initializeSQL)
 	return err
 }
 
@@ -303,10 +308,6 @@ func cmdInit(fs *flag.FlagSet, args []string) error {
 		return err
 	}
 
-	if _, err := db.Exec(initializeSQL); err != nil {
-		return err
-	}
-
 	// XXX: There's technically no reason to keep images as symlinks,
 	// we might just keep absolute paths in the database as well.
 	if err := os.MkdirAll(
@@ -657,7 +658,9 @@ func getOrphanReplacement(webPath string) (*webOrphanImage, error) {
 	}
 
 	parent, err := idForDirectoryPath(tx, path[:len(path)-1], false)
-	if err != nil {
+	if errors.Is(err, sql.ErrNoRows) {
+		return nil, nil
+	} else if err != nil {
 		return nil, err
 	}
 
@@ -684,7 +687,8 @@ func getOrphans() (result []webOrphan, err error) {
 		FROM orphan AS o
 		JOIN image AS i ON o.sha1 = i.sha1
 		LEFT JOIN tag_assignment AS ta ON o.sha1 = ta.sha1
-		GROUP BY o.sha1`)
+		GROUP BY o.sha1
+		ORDER BY path`)
 	if err != nil {
 		return nil, err
 	}
@@ -2700,6 +2704,9 @@ func main() {
 	// Note that the database object has a closing finalizer,
 	// we just additionally print any errors coming from there.
 	if db != nil {
+		if _, err := db.Exec(`PRAGMA optimize`); err != nil {
+			log.Println(err)
+		}
 		if err := db.Close(); err != nil {
 			log.Println(err)
 		}