Changes in uspace/lib/ext2/libext2_directory.c [911ee54:4e36219] in mainline

File:

• uspace/lib/ext2/libext2_directory.c (modified) (5 diffs)

uspace/lib/ext2/libext2_directory.c

@@ -86 +86 @@
  * @param fs pointer to filesystem structure
  * @param inode pointer to inode reference structure
+ * @param pos position within inode to start at, 0 is the first entry
  * @return EOK on success or negative error code on failure
  */
 int ext2_directory_iterator_init(ext2_directory_iterator_t *it,
-    ext2_filesystem_t *fs, ext2_inode_ref_t *inode_ref)
-{
-        int rc;
-        uint32_t block_id;
-        uint32_t block_size;
-        
+    ext2_filesystem_t *fs, ext2_inode_ref_t *inode_ref, aoff64_t pos)
+{       
         it->inode_ref = inode_ref;
         it->fs = fs;
-        
-        /* Get the first data block, so we can get the first entry */
-        rc = ext2_filesystem_get_inode_data_block_index(fs, inode_ref->inode, 0, 
-            &block_id);
-        if (rc != EOK) {
-                return rc;
-        }
-        
-        rc = block_get(&it->current_block, fs->device, block_id, 0);
-        if (rc != EOK) {
-                return rc;
-        }
-        
-        block_size = ext2_superblock_get_block_size(fs->superblock);
-        
-        it->current_offset = 0; 
-        return ext2_directory_iterator_set(it, block_size);
+        it->current = NULL;
+        it->current_offset = 0;
+        it->current_block = NULL;
+        
+        return ext2_directory_iterator_seek(it, pos);
 }
 
@@ -124 +109 @@
 int ext2_directory_iterator_next(ext2_directory_iterator_t *it)
 {
+        uint16_t skip;
+        
+        assert(it->current != NULL);
+        
+        skip = ext2_directory_entry_ll_get_entry_length(it->current);
+        
+        return ext2_directory_iterator_seek(it, it->current_offset + skip);
+}
+
+/**
+ * Seek the directory iterator to the given byte offset within the inode.
+ * 
+ * @param it pointer to iterator to initialize
+ * @return EOK on success or negative error code on failure
+ */
+int ext2_directory_iterator_seek(ext2_directory_iterator_t *it, aoff64_t pos)
+{
         int rc;
-        uint16_t skip;
+        
         uint64_t size;
         aoff64_t current_block_idx;
@@ -132 +134 @@
         uint32_t block_size;
         
-        assert(it->current != NULL);
-        
-        skip = ext2_directory_entry_ll_get_entry_length(it->current);
         size = ext2_inode_get_size(it->fs->superblock, it->inode_ref->inode);
         
+        /* The iterator is not valid until we seek to the desired position */
+        it->current = NULL;
+        
         /* Are we at the end? */
-        if (it->current_offset + skip >= size) {
-                rc = block_put(it->current_block);
-                it->current_block = NULL;
-                it->current = NULL;
-                if (rc != EOK) {
-                        return rc;
+        if (pos >= size) {              
+                if (it->current_block) {
+                        rc = block_put(it->current_block);
+                        it->current_block = NULL;
+                        if (rc != EOK) {
+                                return rc;
+                        }
                 }
                 
-                it->current_offset += skip;
+                it->current_offset = pos;
                 return EOK;
         }
@@ -152 +155 @@
         block_size = ext2_superblock_get_block_size(it->fs->superblock);
         current_block_idx = it->current_offset / block_size;
-        next_block_idx = (it->current_offset + skip) / block_size;
-        
-        /* If we are moving accross block boundary,
+        next_block_idx = pos / block_size;
+        
+        /* If we don't have a block or are moving accross block boundary,
          * we need to get another block
          */
-        if (current_block_idx != next_block_idx) {
-                rc = block_put(it->current_block);
-                it->current_block = NULL;
-                it->current = NULL;
-                if (rc != EOK) {
-                        return rc;
+        if (it->current_block == NULL || current_block_idx != next_block_idx) {         
+                if (it->current_block) {
+                        rc = block_put(it->current_block);
+                        it->current_block = NULL;
+                        if (rc != EOK) {
+                                return rc;
+                        }
                 }
                 
@@ -179 +183 @@
         }
         
-        it->current_offset += skip;
+        it->current_offset = pos;
         return ext2_directory_iterator_set(it, block_size);
 }
 
+/** Setup the entry at the current iterator offset.
+ * 
+ * This function checks the validity of the directory entry,
+ * before setting the data pointer.
+ *
+ * @return EOK on success or error code on failure 
+ */
 static int ext2_directory_iterator_set(ext2_directory_iterator_t *it,
     uint32_t block_size)