wimlib_export_image(): improve duplicate image detection

[wimlib] / include / wimlib.h

diff --git a/include/wimlib.h b/include/wimlib.h
index ac42e81a8f7f9f24b288ae00bf30d79915e5e010..6842e35da43178980dff61213a2df455a12ef8ad 100644 (file)
--- a/include/wimlib.h
+++ b/include/wimlib.h
@@ -2493,10 +2493,12 @@ enum wimlib_error_code {
        WIMLIB_ERR_MOUNTED_IMAGE_IS_BUSY              = 79,
        WIMLIB_ERR_NOT_A_MOUNTPOINT                   = 80,
        WIMLIB_ERR_NOT_PERMITTED_TO_UNMOUNT           = 81,
-       WIMLIB_ERR_FVE_LOCKED_VOLUME                  = 82,
+       WIMLIB_ERR_FVE_LOCKED_VOLUME                  = 82,
        WIMLIB_ERR_UNABLE_TO_READ_CAPTURE_CONFIG      = 83,
-       WIMLIB_ERR_WIM_IS_INCOMPLETE                  = 84,
+       WIMLIB_ERR_WIM_IS_INCOMPLETE                  = 84,
        WIMLIB_ERR_COMPACTION_NOT_POSSIBLE            = 85,
+       WIMLIB_ERR_IMAGE_HAS_MULTIPLE_REFERENCES      = 86,
+       WIMLIB_ERR_DUPLICATE_EXPORTED_IMAGE           = 87,
 };
 
 
@@ -2715,13 +2717,17 @@ wimlib_delete_path(WIMStruct *wim, int image,
  *
  * Export an image, or all images, from a ::WIMStruct into another ::WIMStruct.
  *
- * Note: after calling this function, the exported WIM image(s) cannot be
- * independently modified because the image metadata will be shared between the
- * two ::WIMStruct's.  In addition, @p dest_wim will depend on @p src_wim, so @p
- * src_wim cannot be freed until @p dest_wim is ready to be freed as well.
+ * Specifically, if the destination ::WIMStruct contains <tt>n</tt> images, then
+ * the source image(s) will be appended, in order, starting at destination index
+ * <tt>n + 1</tt>.  By default, all image metadata will be exported verbatim,
+ * but certain changes can be made by passing appropriate parameters.
  *
- * Note: no changes are committed to disk until wimlib_write() or
- * wimlib_overwrite() is called.
+ * wimlib_export_image() is only an in-memory operation; no changes are
+ * committed to disk until wimlib_write() or wimlib_overwrite() is called.
+ *
+ * A limitation of the current implementation of wimlib_export_image() is that
+ * the directory tree of a source or destination image cannot be updated
+ * following an export until one of the two images has been freed from memory.
  *
  * @param src_wim
  *     The WIM from which to export the images, specified as a pointer to the
@@ -2752,6 +2758,9 @@ wimlib_delete_path(WIMStruct *wim, int image,
  *
  * @return 0 on success; a ::wimlib_error_code value on failure.
  *
+ * @retval ::WIMLIB_ERR_DUPLICATE_EXPORTED_IMAGE
+ *     One or more of the source images had already been exported into the
+ *     destination WIM.
  * @retval ::WIMLIB_ERR_IMAGE_NAME_COLLISION
  *     One or more of the names being given to an exported image was already in
  *     use in the destination WIM.
@@ -3071,11 +3080,14 @@ wimlib_extract_xml_data(WIMStruct *wim, FILE *fp);
 /**
  * @ingroup G_general
  *
- * Free all memory allocated for a WIMStruct and close all files associated with
- * it.
+ * Release a reference to a ::WIMStruct.  If the ::WIMStruct is still referenced
+ * by other ::WIMStruct's (e.g. following calls to wimlib_export_image() or
+ * wimlib_reference_resources()), then the library will free it later, when the
+ * last reference is released; otherwise it is freed immediately and any
+ * associated file descriptors are closed.
  *
  * @param wim
- *     Pointer to the ::WIMStruct to free.  If @c NULL, no action is taken.
+ *     Pointer to the ::WIMStruct to release.  If @c NULL, no action is taken.
  */
 extern void
 wimlib_free(WIMStruct *wim);
@@ -3466,6 +3478,10 @@ wimlib_join_with_progress(const wimlib_tchar * const *swms,
  *     Another process is currently modifying the WIM file.
  * @retval ::WIMLIB_ERR_FUSE
  *     A non-zero status code was returned by @c fuse_main().
+ * @retval ::WIMLIB_ERR_IMAGE_HAS_MULTIPLE_REFERENCES
+ *     There are currently multiple references to the WIM image as a result of
+ *     a call to wimlib_export_image().  Free one before attempting the
+ *     read-write mount.
  * @retval ::WIMLIB_ERR_INVALID_IMAGE
  *     @p image does not exist in @p wim.
  * @retval ::WIMLIB_ERR_INVALID_PARAM
@@ -3760,11 +3776,7 @@ wimlib_reference_resource_files(WIMStruct *wim,
  * @param ref_flags
  *     Reserved; must be 0.
  *
- * @return 0 on success; a ::wimlib_error_code value on failure.  On success,
- * the ::WIMStruct's of the @p resource_wims are referenced internally by @p wim
- * and must not be freed with wimlib_free() or overwritten with
- * wimlib_overwrite() until @p wim has been freed with wimlib_free(), or
- * immediately before freeing @p wim with wimlib_free().
+ * @return 0 on success; a ::wimlib_error_code value on failure.
  */
 extern int
 wimlib_reference_resources(WIMStruct *wim, WIMStruct **resource_wims,
@@ -4353,6 +4365,9 @@ wimlib_unmount_image_with_progress(const wimlib_tchar *dir,
  * @retval ::WIMLIB_ERR_FVE_LOCKED_VOLUME
  *     Windows-only: One of the "add" commands attempted to add files from an
  *     encrypted BitLocker volume that hasn't yet been unlocked.
+ * @retval ::WIMLIB_ERR_IMAGE_HAS_MULTIPLE_REFERENCES
+ *     There are currently multiple references to the WIM image as a result of
+ *     a call to wimlib_export_image().  Free one before attempting the update.
  * @retval ::WIMLIB_ERR_INVALID_CAPTURE_CONFIG
  *     The contents of a capture configuration file were invalid.
  * @retval ::WIMLIB_ERR_INVALID_IMAGE