Split recursive directory iterator

The recursive part and the filter part are split up, the recursive
iterator wrapper is moved into libsquashfs and the libio iterator
is modified to use that internally instead of implementig the
recursion step.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 253 insertions, 0 deletions

diff --git a/lib/sqfs/src/io/dir_rec.c b/lib/sqfs/src/io/dir_rec.c
new file mode 100644
index 0000000..a5d53af
--- /dev/null
+++ b/lib/sqfs/src/io/dir_rec.c
@@ -0,0 +1,253 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * dir_rec.c
+ *
+ * Copyright (C) 2023 David Oberhollenzer <goliath@infraroot.at>
+ */
+#define SQFS_BUILDING_DLL
+#include "config.h"
+
+#include "util/util.h"
+#include "sqfs/dir_entry.h"
+#include "sqfs/error.h"
+#include "sqfs/io.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct dir_stack_t {
+	struct dir_stack_t *next;
+	sqfs_dir_iterator_t *dir;
+	char name[];
+} dir_stack_t;
+
+typedef struct {
+	sqfs_dir_iterator_t base;
+
+	int state;
+	dir_stack_t *top;
+
+	dir_stack_t *next_top;
+} dir_tree_iterator_t;
+
+static void pop(dir_tree_iterator_t *it)
+{
+	if (it->top != NULL) {
+		dir_stack_t *ent = it->top;
+		it->top = it->top->next;
+
+		sqfs_drop(ent->dir);
+		free(ent);
+	}
+}
+
+static sqfs_dir_entry_t *expand_path(const dir_tree_iterator_t *it,
+				     sqfs_dir_entry_t *ent)
+{
+	size_t slen = strlen(ent->name) + 1, plen = 0;
+	char *dst;
+	void *new;
+
+	for (dir_stack_t *sit = it->top; sit != NULL; sit = sit->next) {
+		if (sit->name[0] != '\0')
+			plen += strlen(sit->name) + 1;
+	}
+
+	if (plen == 0)
+		return ent;
+
+	new = realloc(ent, sizeof(*ent) + plen + slen);
+	if (new == NULL) {
+		free(ent);
+		return NULL;
+	}
+
+	ent = new;
+	memmove(ent->name + plen, ent->name, slen);
+	dst = ent->name + plen;
+
+	for (dir_stack_t *sit = it->top; sit != NULL; sit = sit->next) {
+		size_t len = strlen(sit->name);
+		if (len > 0) {
+			*(--dst) = '/';
+			dst -= len;
+			memcpy(dst, sit->name, len);
+		}
+	}
+
+	return ent;
+}
+
+/*****************************************************************************/
+
+static void destroy(sqfs_object_t *obj)
+{
+	dir_tree_iterator_t *it = (dir_tree_iterator_t *)obj;
+
+	while (it->top != NULL)
+		pop(it);
+
+	if (it->next_top != NULL) {
+		sqfs_drop(it->next_top->dir);
+		free(it->next_top);
+	}
+
+	free(it);
+}
+
+static int next(sqfs_dir_iterator_t *base, sqfs_dir_entry_t **out)
+{
+	dir_tree_iterator_t *it = (dir_tree_iterator_t *)base;
+	sqfs_dir_entry_t *ent = NULL;
+	int ret;
+
+	*out = NULL;
+	if (it->state != 0)
+		return it->state;
+
+	if (it->next_top != NULL) {
+		it->next_top->next = it->top;
+		it->top = it->next_top;
+		it->next_top = NULL;
+	}
+
+	for (;;) {
+		if (it->top == NULL) {
+			ret = 1;
+			goto fail;
+		}
+
+		ret = it->top->dir->next(it->top->dir, &ent);
+		if (ret < 0)
+			goto fail;
+
+		if (ret > 0) {
+			pop(it);
+			continue;
+		}
+
+		if (!strcmp(ent->name, ".") || !strcmp(ent->name, "..")) {
+			free(ent);
+			ent = NULL;
+			continue;
+		}
+
+		break;
+	}
+
+	ent = expand_path(it, ent);
+	if (ent == NULL) {
+		it->state = SQFS_ERROR_ALLOC;
+		return it->state;
+	}
+
+	if (S_ISDIR(ent->mode)) {
+		sqfs_dir_iterator_t *sub = NULL;
+		const char *name = strrchr(ent->name, '/');
+		name = (name == NULL) ? ent->name : (name + 1);
+
+		ret = it->top->dir->open_subdir(it->top->dir, &sub);
+		if (ret != 0)
+			goto fail;
+
+		it->next_top = alloc_flex(sizeof(*(it->next_top)), 1,
+					  strlen(name) + 1);
+		if (it->next_top == NULL) {
+			sqfs_drop(sub);
+			goto fail;
+		}
+
+		strcpy(it->next_top->name, name);
+		it->next_top->dir = sub;
+	}
+
+	*out = ent;
+	return it->state;
+fail:
+	free(ent);
+	it->state = ret;
+	return it->state;
+}
+
+static int read_link(sqfs_dir_iterator_t *base, char **out)
+{
+	dir_tree_iterator_t *it = (dir_tree_iterator_t *)base;
+
+	*out = NULL;
+	if (it->top == NULL)
+		return SQFS_ERROR_NO_ENTRY;
+
+	return it->top->dir->read_link(it->top->dir, out);
+}
+
+static int open_subdir(sqfs_dir_iterator_t *base, sqfs_dir_iterator_t **out)
+{
+	dir_tree_iterator_t *it = (dir_tree_iterator_t *)base;
+
+	*out = NULL;
+	if (it->top == NULL)
+		return SQFS_ERROR_NO_ENTRY;
+
+	return it->top->dir->open_subdir(it->top->dir, out);
+}
+
+static void ignore_subdir(sqfs_dir_iterator_t *base)
+{
+	dir_tree_iterator_t *it = (dir_tree_iterator_t *)base;
+
+	if (it->next_top != NULL) {
+		sqfs_drop(it->next_top->dir);
+		free(it->next_top);
+		it->next_top = NULL;
+	}
+}
+
+static int open_file_ro(sqfs_dir_iterator_t *base, sqfs_istream_t **out)
+{
+	dir_tree_iterator_t *it = (dir_tree_iterator_t *)base;
+
+	*out = NULL;
+	if (it->top == NULL)
+		return SQFS_ERROR_NO_ENTRY;
+
+	return it->top->dir->open_file_ro(it->top->dir, out);
+}
+
+static int read_xattr(sqfs_dir_iterator_t *base, sqfs_xattr_t **out)
+{
+	dir_tree_iterator_t *it = (dir_tree_iterator_t *)base;
+
+	*out = NULL;
+	if (it->top == NULL)
+		return SQFS_ERROR_NO_ENTRY;
+
+	return it->top->dir->read_xattr(it->top->dir, out);
+}
+
+int sqfs_dir_iterator_create_recursive(sqfs_dir_iterator_t **out,
+				       sqfs_dir_iterator_t *base)
+{
+	dir_tree_iterator_t *it = calloc(1, sizeof(*it));
+
+	*out = NULL;
+	if (it == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	it->next_top = calloc(1, sizeof(*(it->next_top)) + 1);
+	if (it->next_top == NULL) {
+		free(it);
+		return SQFS_ERROR_ALLOC;
+	}
+	it->next_top->dir = sqfs_grab(base);
+
+	sqfs_object_init(it, destroy, NULL);
+	((sqfs_dir_iterator_t *)it)->next = next;
+	((sqfs_dir_iterator_t *)it)->read_link = read_link;
+	((sqfs_dir_iterator_t *)it)->open_subdir = open_subdir;
+	((sqfs_dir_iterator_t *)it)->ignore_subdir = ignore_subdir;
+	((sqfs_dir_iterator_t *)it)->open_file_ro = open_file_ro;
+	((sqfs_dir_iterator_t *)it)->read_xattr = read_xattr;
+
+	*out = (sqfs_dir_iterator_t *)it;
+	return 0;
+}