#ifndef _WIMLIB_METADATA_H
#define _WIMLIB_METADATA_H
+#include "wimlib/blob_table.h"
#include "wimlib/list.h"
#include "wimlib/types.h"
#include "wimlib/wim.h"
-#ifdef WITH_NTFS_3G
-struct _ntfs_volume;
-#endif
-
-/* Metadata for a WIM image */
+/*
+ * This structure holds the directory tree that comprises a WIM image, along
+ * with other information maintained at the image level. It is populated either
+ * by reading and parsing a metadata resource or by scanning new files.
+ *
+ * An image that hasn't been modified from its on-disk copy is considered
+ * "clean" and is loaded from its metadata resource on demand by
+ * select_wim_image(). Such an image may be unloaded later to save memory when
+ * a different image is selected. An image that has been modified or has been
+ * created from scratch, on the other hand, is considered "dirty" and is never
+ * automatically unloaded.
+ *
+ * To implement exports, it's allowed that multiple WIMStructs reference the
+ * same wim_image_metadata.
+ */
struct wim_image_metadata {
- /* Number of WIMStruct's that are sharing this image metadata (from
- * calls to wimlib_export_image().) */
- unsigned long refcnt;
+ /* Number of WIMStructs that reference this image. This will always be
+ * >= 1. It may be > 1 if this image has been exported. */
+ u32 refcnt;
+
+ /* Number of WIMStructs that have this image selected as their
+ * current_image. This will always be <= 'refcnt' and may be 0. */
+ u32 selected_refcnt;
- /* Pointer to the root dentry of the image. */
+ /* Pointer to the root dentry of this image, or NULL if this image is
+ * completely empty or is not currently loaded. */
struct wim_dentry *root_dentry;
- /* Pointer to the security data of the image. */
+ /* Pointer to the security data of this image, or NULL if this image is
+ * not currently loaded. */
struct wim_security_data *security_data;
- /* Pointer to the lookup table entry for this image's metadata resource
- */
- struct wim_lookup_table_entry *metadata_lte;
-
- /* Linked list of 'struct wim_inode's for this image. */
- struct list_head inode_list;
-
- /* Linked list of 'struct wim_lookup_table_entry's for this image that
- * are referred to in the dentry tree, but have not had a SHA1 message
- * digest calculated yet and therefore have not been inserted into the
- * WIM's lookup table. This list is added to during wimlib_add_image()
- * and wimlib_mount_image() (read-write only). */
- struct list_head unhashed_streams;
-
- /* 1 iff the dentry tree has been modified. If this is the case, the
- * memory for the dentry tree should not be freed when switching to a
- * different WIM image. */
- u8 modified : 1;
-
-#ifdef WITH_NTFS_3G
- struct _ntfs_volume *ntfs_vol;
-#endif
+ /* Pointer to the blob descriptor for this image's metadata resource.
+ * If this image metadata is sourced from a WIM file (as opposed to
+ * being created from scratch) and hasn't been modified from the version
+ * in that WIM file, then this blob descriptor's data corresponds to the
+ * WIM backing source. Otherwise, this blob descriptor is a dummy entry
+ * with blob_location==BLOB_NONEXISTENT. */
+ struct blob_descriptor *metadata_blob;
+
+ /* Linked list of 'struct wim_inode's for this image, or an empty list
+ * if this image is completely empty or is not currently loaded. */
+ struct hlist_head inode_list;
+
+ /* Linked list of 'struct blob_descriptor's for blobs that are
+ * referenced by this image's dentry tree, but have not had their SHA-1
+ * message digests calculated yet and therefore have not been inserted
+ * into the WIMStruct's blob table. This list is appended to when files
+ * are scanned for inclusion in this WIM image. */
+ struct list_head unhashed_blobs;
+
+ /* Are the filecount/bytecount stats (in the XML info) out of date for
+ * this image? */
+ bool stats_outdated;
};
/* Retrieve the metadata of the image in @wim currently selected with
return wim_get_current_image_metadata(wim)->security_data;
}
-/* Iterate over each inode in a WIM image that has not yet been hashed */
+/* Return true iff the specified image has been changed since being read from
+ * its backing file or has been created from scratch. */
+static inline bool
+is_image_dirty(const struct wim_image_metadata *imd)
+{
+ /* The only possible values here are BLOB_NONEXISTENT and BLOB_IN_WIM */
+ return imd->metadata_blob->blob_location == BLOB_NONEXISTENT;
+}
+
+/* Return true iff the specified image is unchanged since being read from the
+ * specified backing WIM file. */
+static inline bool
+is_image_unchanged_from_wim(const struct wim_image_metadata *imd,
+ const WIMStruct *wim)
+{
+ return !is_image_dirty(imd) && imd->metadata_blob->rdesc->wim == wim;
+}
+
+/* Mark the metadata for the specified WIM image "dirty" following changes to
+ * the image's directory tree. This records that the metadata no longer matches
+ * the version in the WIM file (if any) and that its stats are out of date. */
+static inline void
+mark_image_dirty(struct wim_image_metadata *imd)
+{
+ blob_release_location(imd->metadata_blob);
+ imd->stats_outdated = true;
+}
+
+/* Return true iff the specified image is currently loaded into memory. */
+static inline bool
+is_image_loaded(const struct wim_image_metadata *imd)
+{
+ /* Check security_data rather than root_dentry, since root_dentry will
+ * be NULL for a completely empty image whereas security_data will still
+ * be non-NULL in that case. */
+ return imd->security_data != NULL;
+}
+
+/* Return true iff it is okay to unload the specified image. The image can be
+ * unloaded if no WIMStructs have it selected and it is not dirty. */
+static inline bool
+can_unload_image(const struct wim_image_metadata *imd)
+{
+ return imd->selected_refcnt == 0 && !is_image_dirty(imd);
+}
+
+/* Iterate over each inode in a WIM image */
#define image_for_each_inode(inode, imd) \
- list_for_each_entry(inode, &imd->inode_list, i_list)
+ hlist_for_each_entry(inode, &(imd)->inode_list, i_hlist_node)
-/* Iterate over each stream in a WIM image that has not yet been hashed */
-#define image_for_each_unhashed_stream(lte, imd) \
- list_for_each_entry(lte, &imd->unhashed_streams, unhashed_list)
+/* Iterate over each inode in a WIM image (safe against inode removal) */
+#define image_for_each_inode_safe(inode, tmp, imd) \
+ hlist_for_each_entry_safe(inode, tmp, &(imd)->inode_list, i_hlist_node)
-/* Iterate over each stream in a WIM image that has not yet been hashed (safe
- * against stream removal) */
-#define image_for_each_unhashed_stream_safe(lte, tmp, imd) \
- list_for_each_entry_safe(lte, tmp, &imd->unhashed_streams, unhashed_list)
+/* Iterate over each blob in a WIM image that has not yet been hashed */
+#define image_for_each_unhashed_blob(blob, imd) \
+ list_for_each_entry(blob, &(imd)->unhashed_blobs, unhashed_list)
+
+/* Iterate over each blob in a WIM image that has not yet been hashed (safe
+ * against blob removal) */
+#define image_for_each_unhashed_blob_safe(blob, tmp, imd) \
+ list_for_each_entry_safe(blob, tmp, &(imd)->unhashed_blobs, unhashed_list)
extern void
-put_image_metadata(struct wim_image_metadata *imd,
- struct wim_lookup_table *table);
+put_image_metadata(struct wim_image_metadata *imd);
extern int
append_image_metadata(WIMStruct *wim, struct wim_image_metadata *imd);
extern struct wim_image_metadata *
-new_image_metadata(void) _malloc_attribute;
+new_empty_image_metadata(void);
+
+extern struct wim_image_metadata *
+new_unloaded_image_metadata(struct blob_descriptor *metadata_blob);
#endif /* _WIMLIB_METADATA_H */
git://wimlib.net / wimlib / blobdiff