libsqfs: dir reader: encapsulate internal state in a separate object

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

3 files changed, 76 insertions, 29 deletions

diff --git a/include/sqfs/dir_reader.h b/include/sqfs/dir_reader.h
index abd49bd..eb90b7a 100644
--- a/include/sqfs/dir_reader.h
+++ b/include/sqfs/dir_reader.h
@@ -21,6 +21,7 @@
 #define SQFS_DIR_READER_H
 
 #include "sqfs/predef.h"
+#include "sqfs/meta_reader.h"
 
 /**
  * @file dir_reader.h
@@ -97,6 +98,57 @@ typedef enum {
 	SQFS_DIR_OPEN_ALL_FLAGS = 0x00000001,
 } SQFS_DIR_OPEN_FLAGS;
 
+/**
+ * @brief sqfs_dir_reader_state_t
+ *
+ * @extends sqfs_readdir_state_t
+ *
+ * A meta data cursor for reading a directory, but with additional data
+ * for the @ref sqfs_dir_reader_t, e.g. for resolving inodes.
+ */
+struct sqfs_dir_reader_state_t {
+	/**
+	 * @brief Base cursor structure for the directory meta data
+	 */
+	sqfs_readdir_state_t cursor;
+
+	/**
+	 * @brief An inode reference to the parent inode of the directory
+	 *
+	 * This is only available if the reader was created with
+	 * the @ref SQFS_DIR_READER_DOT_ENTRIES flag and the behavior was
+	 * not disabled when opening the directory.
+	 */
+	sqfs_u64 parent_ref;
+
+	/**
+	 * @brief A reference to the inode of the directory itself
+	 *
+	 * This is only available if the reader was created with
+	 * the @ref SQFS_DIR_READER_DOT_ENTRIES flag and the behavior was
+	 * not disabled when opening the directory.
+	 */
+	sqfs_u64 cur_ref;
+
+	/**
+	 * @brief A reference to the current entries inode
+	 *
+	 * After a successfull call to @ref sqfs_dir_reader_read, this contains
+	 * a reference to the inode coresponding to the returned entry.
+	 */
+	sqfs_u64 ent_ref;
+
+	/**
+	 * @brief An opaque, internal state value
+	 */
+	sqfs_u8 state;
+
+	/**
+	 * @brief A backup of `state` to reset the state if requested
+	 */
+	sqfs_u8 start_state;
+};
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/include/sqfs/predef.h b/include/sqfs/predef.h
index fbc6519..8e7c1b8 100644
--- a/include/sqfs/predef.h
+++ b/include/sqfs/predef.h
@@ -80,6 +80,7 @@ typedef struct sqfs_compressor_config_t sqfs_compressor_config_t;
 typedef struct sqfs_compressor_t sqfs_compressor_t;
 typedef struct sqfs_dir_writer_t sqfs_dir_writer_t;
 typedef struct sqfs_dir_reader_t sqfs_dir_reader_t;
+typedef struct sqfs_dir_reader_state_t sqfs_dir_reader_state_t;
 typedef struct sqfs_id_table_t sqfs_id_table_t;
 typedef struct sqfs_meta_reader_t sqfs_meta_reader_t;
 typedef struct sqfs_meta_writer_t sqfs_meta_writer_t;
diff --git a/lib/sqfs/src/dir_reader.c b/lib/sqfs/src/dir_reader.c
index c44198e..ce93795 100644
--- a/lib/sqfs/src/dir_reader.c
+++ b/lib/sqfs/src/dir_reader.c
@@ -33,16 +33,11 @@ struct sqfs_dir_reader_t {
 	sqfs_meta_reader_t *meta_inode;
 	sqfs_super_t super;
 
-	sqfs_readdir_state_t it;
-
 	sqfs_u32 flags;
 
-	int start_state;
-	int state;
-	sqfs_u64 parent_ref;
-	sqfs_u64 cur_ref;
-	sqfs_u64 ent_ref;
 	rbtree_t dcache;
+
+	sqfs_dir_reader_state_t state;
 };
 
 static int inode_copy(const sqfs_inode_generic_t *inode,
@@ -192,7 +187,6 @@ sqfs_dir_reader_t *sqfs_dir_reader_create(const sqfs_super_t *super,
 
 	rd->super = *super;
 	rd->flags = flags;
-	rd->state = DIR_STATE_NONE;
 	return rd;
 fail_mdir:
 	sqfs_drop(rd->meta_inode);
@@ -214,7 +208,7 @@ int sqfs_dir_reader_open_dir(sqfs_dir_reader_t *rd,
 	if (flags & (~SQFS_DIR_OPEN_ALL_FLAGS))
 		return SQFS_ERROR_UNSUPPORTED;
 
-	ret = sqfs_readdir_state_init(&rd->it, &rd->super, inode);
+	ret = sqfs_readdir_state_init(&rd->state.cursor, &rd->super, inode);
 	if (ret)
 		return ret;
 
@@ -226,21 +220,21 @@ int sqfs_dir_reader_open_dir(sqfs_dir_reader_t *rd,
 			parent = inode->data.dir.parent_inode;
 		}
 
-		if (dcache_find(rd, inode->base.inode_number, &rd->cur_ref))
+		if (dcache_find(rd, inode->base.inode_number, &rd->state.cur_ref))
 			return SQFS_ERROR_NO_ENTRY;
 
-		if (rd->cur_ref == rd->super.root_inode_ref) {
-			rd->parent_ref = rd->cur_ref;
-		} else if (dcache_find(rd, parent, &rd->parent_ref)) {
+		if (rd->state.cur_ref == rd->super.root_inode_ref) {
+			rd->state.parent_ref = rd->state.cur_ref;
+		} else if (dcache_find(rd, parent, &rd->state.parent_ref)) {
 			return SQFS_ERROR_NO_ENTRY;
 		}
 
-		rd->state = DIR_STATE_OPENED;
+		rd->state.state = DIR_STATE_OPENED;
 	} else {
-		rd->state = DIR_STATE_ENTRIES;
+		rd->state.state = DIR_STATE_ENTRIES;
 	}
 
-	rd->start_state = rd->state;
+	rd->state.start_state = rd->state.state;
 	return 0;
 }
 
@@ -266,19 +260,19 @@ int sqfs_dir_reader_read(sqfs_dir_reader_t *rd, sqfs_dir_node_t **out)
 {
 	int err;
 
-	switch (rd->state) {
+	switch (rd->state.state) {
 	case DIR_STATE_OPENED:
 		err = mk_dummy_entry(".", out);
 		if (err == 0) {
-			rd->state = DIR_STATE_DOT;
-			rd->ent_ref = rd->cur_ref;
+			rd->state.state = DIR_STATE_DOT;
+			rd->state.ent_ref = rd->state.cur_ref;
 		}
 		return err;
 	case DIR_STATE_DOT:
 		err = mk_dummy_entry("..", out);
 		if (err == 0) {
-			rd->state = DIR_STATE_ENTRIES;
-			rd->ent_ref = rd->parent_ref;
+			rd->state.state = DIR_STATE_ENTRIES;
+			rd->state.ent_ref = rd->state.parent_ref;
 		}
 		return err;
 	case DIR_STATE_ENTRIES:
@@ -287,17 +281,17 @@ int sqfs_dir_reader_read(sqfs_dir_reader_t *rd, sqfs_dir_node_t **out)
 		return SQFS_ERROR_SEQUENCE;
 	}
 
-	return sqfs_meta_reader_readdir(rd->meta_dir, &rd->it,
-					out, NULL, &rd->ent_ref);
+	return sqfs_meta_reader_readdir(rd->meta_dir, &rd->state.cursor,
+					out, NULL, &rd->state.ent_ref);
 }
 
 int sqfs_dir_reader_rewind(sqfs_dir_reader_t *rd)
 {
-	if (rd->state == DIR_STATE_NONE)
+	if (rd->state.state == DIR_STATE_NONE)
 		return SQFS_ERROR_SEQUENCE;
 
-	sqfs_readdir_state_reset(&rd->it);
-	rd->state = rd->start_state;
+	sqfs_readdir_state_reset(&rd->state.cursor);
+	rd->state.state = rd->state.start_state;
 	return 0;
 }
 
@@ -307,12 +301,12 @@ int sqfs_dir_reader_get_inode(sqfs_dir_reader_t *rd,
 	int ret;
 
 	ret = sqfs_meta_reader_read_inode(rd->meta_inode, &rd->super,
-					  rd->ent_ref >> 16,
-					  rd->ent_ref & 0x0FFFF, inode);
+					  rd->state.ent_ref >> 16,
+					  rd->state.ent_ref & 0x0FFFF, inode);
 	if (ret != 0)
 		return ret;
 
-	return dcache_add(rd, *inode, rd->ent_ref);
+	return dcache_add(rd, *inode, rd->state.ent_ref);
 }
 
 int sqfs_dir_reader_get_root_inode(sqfs_dir_reader_t *rd,