directory: replace dirvec with doubly linked list

Random access is not needed, and a linked list is easier to manage: we
don't need to (re-)allocate the pointer array.

Makefile.am

@@ -90,7 +90,6 @@ mpd_headers = \
 	src/inotify_source.h \
 	src/inotify_queue.h \
 	src/inotify_update.h \
-	src/dirvec.h \
 	src/gcc.h \
 	src/decoder_list.h \
 	src/decoder_print.h \
@@ -257,7 +256,6 @@ src_mpd_SOURCES = \
 	src/db_visitor.h \
 	src/db_selection.h \
 	src/db/simple_db_plugin.c src/db/simple_db_plugin.h \
-	src/dirvec.c \
 	src/exclude.c \
 	src/fd_util.c \
 	src/fifo_buffer.c src/fifo_buffer.h \

src/db/simple_db_plugin.c

@@ -24,6 +24,7 @@
 #include "db_selection.h"
 #include "db_visitor.h"
 #include "db_save.h"
+#include "db_lock.h"
 #include "conf.h"
 #include "glib_compat.h"
 #include "directory.h"
@@ -266,8 +267,11 @@ simple_db_visit(struct db *_db, const struct db_selection *selection,
 	    !visitor->directory(directory, ctx, error_r))
 		return false;
 
-	return directory_walk(directory, selection->recursive,
+	db_lock();
-			      visitor, ctx, error_r);
+	bool ret = directory_walk(directory, selection->recursive,
+				  visitor, ctx, error_r);
+	db_unlock();
+	return ret;
 }
 
 const struct db_plugin simple_db_plugin = {

src/directory.c

@@ -21,7 +21,9 @@
 #include "directory.h"
 #include "song.h"
 #include "path.h"
+#include "util/list_sort.h"
 #include "db_visitor.h"
+#include "db_lock.h"
 
 #include <glib.h>
 
@@ -40,6 +42,7 @@ directory_new(const char *path, struct directory *parent)
 
 	directory = g_malloc0(sizeof(*directory) -
 			      sizeof(directory->path) + pathlen + 1);
+	INIT_LIST_HEAD(&directory->children);
 	directory->parent = parent;
 	memcpy(directory->path, path, pathlen + 1);
 
@@ -56,10 +59,10 @@ directory_free(struct directory *directory)
 	for (unsigned i = 0; i < directory->songs.nr; ++i)
 		song_free(directory->songs.base[i]);
 
-	for (unsigned i = 0; i < directory->children.nr; ++i)
+	struct directory *child, *n;
-		directory_free(directory->children.base[i]);
+	directory_for_each_child_safe(child, n, directory)
+		directory_free(child);
 
-	dirvec_destroy(&directory->children);
 	songvec_destroy(&directory->songs);
 	g_free(directory);
 	/* this resets last dir returned */
@@ -72,7 +75,10 @@ directory_delete(struct directory *directory)
 	assert(directory != NULL);
 	assert(directory->parent != NULL);
 
-	dirvec_delete(&directory->parent->children, directory);
+	db_lock();
+	list_del(&directory->siblings);
+	db_unlock();
+
 	directory_free(directory);
 }
 
@@ -103,26 +109,39 @@ directory_new_child(struct directory *parent, const char *name_utf8)
 	struct directory *directory = directory_new(path_utf8, parent);
 	g_free(allocated);
 
-	dirvec_add(&parent->children, directory);
+	db_lock();
+	list_add(&directory->siblings, &parent->children);
+	db_unlock();
 	return directory;
 }
 
+struct directory *
+directory_get_child(const struct directory *directory, const char *name)
+{
+	db_lock();
+
+	struct directory *child;
+	directory_for_each_child(child, directory) {
+		if (strcmp(directory_get_name(child), name) == 0) {
+			db_unlock();
+			return child;
+		}
+	}
+
+	db_unlock();
+	return NULL;
+}
+
 void
 directory_prune_empty(struct directory *directory)
 {
-	int i;
+	struct directory *child, *n;
-	struct dirvec *dv = &directory->children;
+	directory_for_each_child_safe(child, n, directory) {
-
-	for (i = dv->nr; --i >= 0; ) {
-		struct directory *child = dv->base[i];
-
 		directory_prune_empty(child);
 
 		if (directory_is_empty(child))
 			directory_delete(child);
 	}
-	if (!dv->nr)
-		dirvec_destroy(dv);
 }
 
 struct directory *
@@ -188,17 +207,27 @@ directory_lookup_song(struct directory *directory, const char *uri)
 
 }
 
+static int
+directory_cmp(G_GNUC_UNUSED void *priv,
+	      struct list_head *_a, struct list_head *_b)
+{
+	const struct directory *a = (const struct directory *)_a;
+	const struct directory *b = (const struct directory *)_b;
+	return g_utf8_collate(a->path, b->path);
+}
+
 void
 directory_sort(struct directory *directory)
 {
-	int i;
+	db_lock();
-	struct dirvec *dv = &directory->children;
+	list_sort(NULL, &directory->children, directory_cmp);
+	db_unlock();
 
-	dirvec_sort(dv);
 	songvec_sort(&directory->songs);
 
-	for (i = dv->nr; --i >= 0; )
+	struct directory *child;
-		directory_sort(dv->base[i]);
+	directory_for_each_child(child, directory)
+		directory_sort(child);
 }
 
 bool
@@ -225,10 +254,8 @@ directory_walk(const struct directory *directory, bool recursive,
 				return false;
 	}
 
-	const struct dirvec *dv = &directory->children;
+	struct directory *child;
-	for (size_t i = 0; i < dv->nr; ++i) {
+	directory_for_each_child(child, directory) {
-		struct directory *child = dv->base[i];
-
 		if (visitor->directory != NULL &&
 		    !visitor->directory(child, ctx, error_r))
 			return false;

src/directory.h

@@ -21,7 +21,7 @@
 #define MPD_DIRECTORY_H
 
 #include "check.h"
-#include "dirvec.h"
+#include "util/list.h"
 #include "songvec.h"
 #include "playlist_vector.h"
 
@@ -34,10 +34,33 @@
 #define DEVICE_INARCHIVE (dev_t)(-1)
 #define DEVICE_CONTAINER (dev_t)(-2)
 
+#define directory_for_each_child(pos, directory) \
+	list_for_each_entry(pos, &directory->children, siblings)
+
+#define directory_for_each_child_safe(pos, n, directory) \
+	list_for_each_entry_safe(pos, n, &directory->children, siblings)
+
 struct db_visitor;
 
 struct directory {
-	struct dirvec children;
+	/**
+	 * Pointers to the siblings of this directory within the
+	 * parent directory.  It is unused (undefined) in the root
+	 * directory.
+	 *
+	 * This attribute is protected with the global #db_mutex.
+	 * Read access in the update thread does not need protection.
+	 */
+	struct list_head siblings;
+
+	/**
+	 * A doubly linked list of child directories.
+	 *
+	 * This attribute is protected with the global #db_mutex.
+	 * Read access in the update thread does not need protection.
+	 */
+	struct list_head children;
+
 	struct songvec songs;
 
 	struct playlist_vector playlists;
@@ -90,7 +113,8 @@ directory_delete(struct directory *directory);
 static inline bool
 directory_is_empty(const struct directory *directory)
 {
-	return directory->children.nr == 0 && directory->songs.nr == 0 &&
+	return list_empty(&directory->children) &&
+		directory->songs.nr == 0 &&
 		playlist_vector_is_empty(&directory->playlists);
 }
 
@@ -116,11 +140,9 @@ G_GNUC_PURE
 const char *
 directory_get_name(const struct directory *directory);
 
-static inline struct directory *
+G_GNUC_PURE
-directory_get_child(const struct directory *directory, const char *name)
+struct directory *
-{
+directory_get_child(const struct directory *directory, const char *name);
-	return dirvec_find(&directory->children, name);
-}
 
 /**
  * Create a new #directory object as a child of the given one.
@@ -171,6 +193,9 @@ directory_lookup_song(struct directory *directory, const char *uri);
 void
 directory_sort(struct directory *directory);
 
+/**
+ * Caller must lock #db_mutex.
+ */
 bool
 directory_walk(const struct directory *directory, bool recursive,
 	       const struct db_visitor *visitor, void *ctx,

src/directory_save.c

@@ -44,8 +44,6 @@ directory_quark(void)
 void
 directory_save(FILE *fp, const struct directory *directory)
 {
-	size_t i;
-
 	if (!directory_is_root(directory)) {
 		fprintf(fp, DIRECTORY_MTIME "%lu\n",
 			(unsigned long)directory->mtime);
@@ -54,9 +52,8 @@ directory_save(FILE *fp, const struct directory *directory)
 			directory_get_path(directory));
 	}
 
-	const struct dirvec *children = &directory->children;
+	struct directory *cur;
-	for (i = 0; i < children->nr; ++i) {
+	directory_for_each_child(cur, directory) {
-		const struct directory *cur = children->base[i];
 		char *base = g_path_get_basename(cur->path);
 
 		fprintf(fp, DIRECTORY_DIR "%s\n", base);

src/dirvec.c

@@ -1,111 +0,0 @@
-/*
- * Copyright (C) 2003-2011 The Music Player Daemon Project
- * http://www.musicpd.org
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- */
-
-#include "config.h"
-#include "dirvec.h"
-#include "directory.h"
-#include "db_lock.h"
-
-#include <glib.h>
-
-#include <assert.h>
-#include <string.h>
-#include <stdlib.h>
-
-static size_t dv_size(const struct dirvec *dv)
-{
-	return dv->nr * sizeof(struct directory *);
-}
-
-/* Only used for sorting/searching a dirvec, not general purpose compares */
-static int dirvec_cmp(const void *d1, const void *d2)
-{
-	const struct directory *a = ((const struct directory * const *)d1)[0];
-	const struct directory *b = ((const struct directory * const *)d2)[0];
-	return g_utf8_collate(a->path, b->path);
-}
-
-void dirvec_sort(struct dirvec *dv)
-{
-	db_lock();
-	qsort(dv->base, dv->nr, sizeof(struct directory *), dirvec_cmp);
-	db_unlock();
-}
-
-struct directory *dirvec_find(const struct dirvec *dv, const char *path)
-{
-	int i;
-
-	db_lock();
-	for (i = dv->nr; --i >= 0; )
-		if (!strcmp(directory_get_name(dv->base[i]), path)) {
-			db_unlock();
-			return dv->base[i];
-		}
-
-	db_unlock();
-
-	return NULL;
-}
-
-int dirvec_delete(struct dirvec *dv, struct directory *del)
-{
-	size_t i;
-
-	db_lock();
-	for (i = 0; i < dv->nr; ++i) {
-		if (dv->base[i] != del)
-			continue;
-		/* we _don't_ call directory_free() here */
-		if (!--dv->nr) {
-			db_unlock();
-			g_free(dv->base);
-			dv->base = NULL;
-			return i;
-		} else {
-			memmove(&dv->base[i], &dv->base[i + 1],
-				(dv->nr - i) * sizeof(struct directory *));
-			dv->base = g_realloc(dv->base, dv_size(dv));
-		}
-		break;
-	}
-	db_unlock();
-
-	return i;
-}
-
-void dirvec_add(struct dirvec *dv, struct directory *add)
-{
-	db_lock();
-	++dv->nr;
-	dv->base = g_realloc(dv->base, dv_size(dv));
-	dv->base[dv->nr - 1] = add;
-	db_unlock();
-}
-
-void dirvec_destroy(struct dirvec *dv)
-{
-	db_lock();
-	dv->nr = 0;
-	db_unlock();
-	if (dv->base) {
-		g_free(dv->base);
-		dv->base = NULL;
-	}
-}

src/dirvec.h

@@ -1,40 +0,0 @@
-/*
- * Copyright (C) 2003-2011 The Music Player Daemon Project
- * http://www.musicpd.org
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- */
-
-#ifndef MPD_DIRVEC_H
-#define MPD_DIRVEC_H
-
-#include <stddef.h>
-
-struct dirvec {
-	struct directory **base;
-	size_t nr;
-};
-
-void dirvec_sort(struct dirvec *dv);
-
-struct directory *dirvec_find(const struct dirvec *dv, const char *path);
-
-int dirvec_delete(struct dirvec *dv, struct directory *del);
-
-void dirvec_add(struct dirvec *dv, struct directory *add);
-
-void dirvec_destroy(struct dirvec *dv);
-
-#endif /* DIRVEC_H */

src/update_walk.c

@@ -121,12 +121,9 @@ delete_directory(struct directory *directory);
 static void
 clear_directory(struct directory *directory)
 {
-	int i;
+	struct directory *child, *n;
-
+	directory_for_each_child_safe(child, n, directory)
-	for (i = directory->children.nr; --i >= 0;)
+		delete_directory(child);
-		delete_directory(directory->children.base[i]);
-
-	assert(directory->children.nr == 0);
 
 	songvec_for_each(&directory->songs, delete_each_song, directory);
 }
@@ -185,11 +182,8 @@ static void
 remove_excluded_from_directory(struct directory *directory,
 			       GSList *exclude_list)
 {
-	int i;
+	struct directory *child, *n;
-	struct dirvec *dv = &directory->children;
+	directory_for_each_child_safe(child, n, directory) {
-
-	for (i = dv->nr; --i >= 0; ) {
-		struct directory *child = dv->base[i];
 		char *name_fs = utf8_to_fs_charset(directory_get_name(child));
 
 		if (exclude_list_check(exclude_list, name_fs)) {
@@ -263,14 +257,12 @@ directory_child_is_regular(const struct directory *directory,
 static void
 removeDeletedFromDirectory(struct directory *directory)
 {
-	int i;
+	struct directory *child, *n;
-	struct dirvec *dv = &directory->children;
+	directory_for_each_child_safe(child, n, directory) {
-
+		if (directory_exists(child))
-	for (i = dv->nr; --i >= 0; ) {
-		if (directory_exists(dv->base[i]))
 			continue;
 
-		delete_directory(dv->base[i]);
+		delete_directory(child);
 		modified = true;
 	}