libfstree: hoist file link pointer into parent structure

Instead of having a file_info_t next pointer, requiring an up-cast
to tree_node_t all the time, simply add a "next_by_type" pointer to
the tree node itself, which can also be used for other purposes by
other node types and removes the need for up-casting.

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

5 files changed, 43 insertions, 58 deletions

diff --git a/bin/gensquashfs/src/mkfs.c b/bin/gensquashfs/src/mkfs.c
index eb9f33b..683077b 100644
--- a/bin/gensquashfs/src/mkfs.c
+++ b/bin/gensquashfs/src/mkfs.c
@@ -12,9 +12,6 @@ static int pack_files(sqfs_block_processor_t *data, fstree_t *fs,
 	sqfs_u64 filesize;
 	sqfs_file_t *file;
 	tree_node_t *node;
-	const char *path;
-	char *node_path;
-	file_info_t *fi;
 	int flags;
 	int ret;
 
@@ -23,10 +20,11 @@ static int pack_files(sqfs_block_processor_t *data, fstree_t *fs,
 		return -1;
 	}
 
-	for (fi = fs->files; fi != NULL; fi = fi->next) {
-		if (fi->input_file == NULL) {
-			node = container_of(fi, tree_node_t, data.file);
+	for (node = fs->files; node != NULL; node = node->next_by_type) {
+		const char *path = node->data.file.input_file;
+		char *node_path = NULL;
 
+		if (path == NULL) {
 			node_path = fstree_get_path(node);
 			if (node_path == NULL) {
 				perror("reconstructing file path");
@@ -37,9 +35,6 @@ static int pack_files(sqfs_block_processor_t *data, fstree_t *fs,
 			assert(ret == 0);
 
 			path = node_path;
-		} else {
-			node_path = NULL;
-			path = fi->input_file;
 		}
 
 		if (!opt->cfg.quiet)
@@ -52,13 +47,14 @@ static int pack_files(sqfs_block_processor_t *data, fstree_t *fs,
 			return -1;
 		}
 
-		flags = fi->flags;
+		flags = node->data.file.flags;
 		filesize = file->get_size(file);
 
 		if (opt->no_tail_packing && filesize > opt->cfg.block_size)
 			flags |= SQFS_BLK_DONT_FRAGMENT;
 
-		ret = write_data_from_file(path, data, &fi->inode, file, flags);
+		ret = write_data_from_file(path, data, &(node->data.file.inode),
+					   file, flags);
 		sqfs_drop(file);
 		free(node_path);
 
diff --git a/bin/gensquashfs/src/sort_by_file.c b/bin/gensquashfs/src/sort_by_file.c
index 6a428ab..8edbb90 100644
--- a/bin/gensquashfs/src/sort_by_file.c
+++ b/bin/gensquashfs/src/sort_by_file.c
@@ -208,41 +208,41 @@ fail_flag:
 
 static void sort_file_list(fstree_t *fs)
 {
-	file_info_t *out = NULL, *out_last = NULL;
+	tree_node_t *out = NULL, *out_last = NULL;
 
 	while (fs->files != NULL) {
-		sqfs_s64 lowest = fs->files->priority;
-		file_info_t *it, *prev;
+		sqfs_s64 lowest = fs->files->data.file.priority;
+		tree_node_t *it, *prev;
 
-		for (it = fs->files; it != NULL; it = it->next) {
-			if (it->priority < lowest)
-				lowest = it->priority;
+		for (it = fs->files; it != NULL; it = it->next_by_type) {
+			if (it->data.file.priority < lowest)
+				lowest = it->data.file.priority;
 		}
 
 		it = fs->files;
 		prev = NULL;
 
 		while (it != NULL) {
-			if (it->priority != lowest) {
+			if (it->data.file.priority != lowest) {
 				prev = it;
-				it = it->next;
+				it = it->next_by_type;
 				continue;
 			}
 
 			if (prev == NULL) {
-				fs->files = it->next;
+				fs->files = it->next_by_type;
 			} else {
-				prev->next = it->next;
+				prev->next_by_type = it->next_by_type;
 			}
 
 			if (out == NULL) {
 				out = it;
 			} else {
-				out_last->next = it;
+				out_last->next_by_type = it;
 			}
 
 			out_last = it;
-			it = it->next;
+			it = it->next_by_type;
 			out_last->next = NULL;
 		}
 	}
@@ -254,13 +254,11 @@ int fstree_sort_files(fstree_t *fs, istream_t *sortfile)
 {
 	const char *filename;
 	size_t line_num = 1;
-	file_info_t *it;
+	tree_node_t *node;
 
-	for (it = fs->files; it != NULL; it = it->next) {
-		tree_node_t *node = container_of(it, tree_node_t, data.file);
-
-		it->priority = 0;
-		it->flags = 0;
+	for (node = fs->files; node != NULL; node = node->next_by_type) {
+		node->data.file.priority = 0;
+		node->data.file.flags = 0;
 		node->flags &= ~FLAG_FILE_ALREADY_MATCHED;
 	}
 
@@ -306,11 +304,9 @@ int fstree_sort_files(fstree_t *fs, istream_t *sortfile)
 
 		have_match = false;
 
-		for (it = fs->files; it != NULL; it = it->next) {
-			tree_node_t *node;
+		for (node = fs->files; node != NULL; node = node->next_by_type) {
 			char *path;
 
-			node = container_of(it, tree_node_t, data.file);
 			if (node->flags & FLAG_FILE_ALREADY_MATCHED)
 				continue;
 
@@ -335,7 +331,6 @@ int fstree_sort_files(fstree_t *fs, istream_t *sortfile)
 			if (do_glob) {
 				ret = fnmatch(line, path,
 					      path_glob ? FNM_PATHNAME : 0);
-
 			} else {
 				ret = strcmp(path, line);
 			}
@@ -344,8 +339,8 @@ int fstree_sort_files(fstree_t *fs, istream_t *sortfile)
 
 			if (ret == 0) {
 				have_match = true;
-				it->flags = flags;
-				it->priority = priority;
+				node->data.file.flags = flags;
+				node->data.file.priority = priority;
 				node->flags |= FLAG_FILE_ALREADY_MATCHED;
 
 				if (!do_glob)
diff --git a/bin/gensquashfs/test/sort_file.c b/bin/gensquashfs/test/sort_file.c
index 4b5caf8..8022cff 100644
--- a/bin/gensquashfs/test/sort_file.c
+++ b/bin/gensquashfs/test/sort_file.c
@@ -151,7 +151,7 @@ static istream_t memstream = {
 int main(int argc, char **argv)
 {
 	fstree_defaults_t fsd;
-	file_info_t *fi;
+	tree_node_t *n;
 	fstree_t fs;
 	size_t i;
 	(void)argc; (void)argv;
@@ -167,8 +167,7 @@ int main(int argc, char **argv)
 
 	fstree_post_process(&fs);
 
-	for (i = 0, fi = fs.files; fi != NULL; fi = fi->next, ++i) {
-		tree_node_t *n = container_of(fi, tree_node_t, data.file);
+	for (i = 0, n = fs.files; n != NULL; n = n->next_by_type, ++i) {
 		char *path = fstree_get_path(n);
 		int ret;
 
@@ -180,8 +179,8 @@ int main(int argc, char **argv)
 		TEST_STR_EQUAL(initial_order[i], path);
 		free(path);
 
-		TEST_EQUAL_I(fi->priority, 0);
-		TEST_EQUAL_I(fi->flags, 0);
+		TEST_EQUAL_I(n->data.file.priority, 0);
+		TEST_EQUAL_I(n->data.file.flags, 0);
 	}
 
 	TEST_EQUAL_UI(i, sizeof(initial_order) / sizeof(initial_order[0]));
@@ -194,8 +193,7 @@ int main(int argc, char **argv)
 
 	TEST_ASSERT(fstree_sort_files(&fs, &memstream) == 0);
 
-	for (i = 0, fi = fs.files; fi != NULL; fi = fi->next, ++i) {
-		tree_node_t *n = container_of(fi, tree_node_t, data.file);
+	for (i = 0, n = fs.files; n != NULL; n = n->next_by_type, ++i) {
 		char *path = fstree_get_path(n);
 		int ret;
 
@@ -207,8 +205,8 @@ int main(int argc, char **argv)
 		TEST_STR_EQUAL(after_sort_order[i], path);
 		free(path);
 
-		TEST_EQUAL_I(fi->priority, priorities[i]);
-		TEST_EQUAL_I(fi->flags, flags[i]);
+		TEST_EQUAL_I(n->data.file.priority, priorities[i]);
+		TEST_EQUAL_I(n->data.file.flags, flags[i]);
 	}
 
 	TEST_EQUAL_UI(i, sizeof(after_sort_order) /
diff --git a/include/fstree.h b/include/fstree.h
index 1a7ad30..044bb48 100644
--- a/include/fstree.h
+++ b/include/fstree.h
@@ -26,9 +26,6 @@ typedef struct tree_node_t tree_node_t;
 typedef struct file_info_t file_info_t;
 typedef struct fstree_t fstree_t;
 
-#define container_of(ptr, type, member) \
-	((type *)((char *)ptr - offsetof(type, member)))
-
 enum {
 	FLAG_DIR_CREATED_IMPLICITLY = 0x01,
 	FLAG_FILE_ALREADY_MATCHED = 0x02,
@@ -36,9 +33,6 @@ enum {
 
 /* Additional meta data stored in a tree_node_t for regular files. */
 struct file_info_t {
-	/* Linked list pointer for files in fstree_t */
-	file_info_t *next;
-
 	/* Path to the input file. */
 	char *input_file;
 
@@ -51,6 +45,8 @@ struct file_info_t {
 
 /* A node in a file system tree */
 struct tree_node_t {
+	tree_node_t *next_by_type;
+
 	/* Parent directory children linked list pointer. */
 	tree_node_t *next;
 
@@ -108,7 +104,7 @@ struct fstree_t {
 	tree_node_t *root;
 
 	/* linear linked list of all regular files */
-	file_info_t *files;
+	tree_node_t *files;
 };
 
 /*
diff --git a/lib/fstree/src/post_process.c b/lib/fstree/src/post_process.c
index 5bf7e7d..f8bc0f7 100644
--- a/lib/fstree/src/post_process.c
+++ b/lib/fstree/src/post_process.c
@@ -55,15 +55,15 @@ fail_ov:
 	return -1;
 }
 
-static file_info_t *file_list_dfs(tree_node_t *n)
+static tree_node_t *file_list_dfs(tree_node_t *n)
 {
 	if (S_ISREG(n->mode)) {
-		n->data.file.next = NULL;
-		return &n->data.file;
+		n->next_by_type = NULL;
+		return n;
 	}
 
 	if (S_ISDIR(n->mode)) {
-		file_info_t *list = NULL, *last = NULL;
+		tree_node_t *list = NULL, *last = NULL;
 
 		for (n = n->data.children; n != NULL; n = n->next) {
 			if (list == NULL) {
@@ -72,11 +72,11 @@ static file_info_t *file_list_dfs(tree_node_t *n)
 					continue;
 				last = list;
 			} else {
-				last->next = file_list_dfs(n);
+				last->next_by_type = file_list_dfs(n);
 			}
 
-			while (last->next != NULL)
-				last = last->next;
+			while (last->next_by_type != NULL)
+				last = last->next_by_type;
 		}
 
 		return list;