process_each_lv: add check_single_lv function

The new check_single_lv() function is called prior to the
existing process_single_lv().  If the check function returns 0,
the LV will not be processed.

The check_single_lv function is meant to be a standard method
to validate the combination of specific command + specific LV,
and decide if the combination is allowed.  The check_single
function can be used by anything that calls process_each_lv.

As commands are migrated to take advantage of command
definitions, each command definition gets its own entry
point which calls process_each for itself, passing a
pair of check_single/process_single functions which can
be specific to the narrowly defined command def.

1 files changed, 14 insertions, 0 deletions

diff --git a/tools/toollib.h b/tools/toollib.h
index d44b825ef..67e45a2ec 100644
--- a/tools/toollib.h
+++ b/tools/toollib.h
@@ -98,6 +98,18 @@ typedef int (*process_single_pvseg_fn_t) (struct cmd_context * cmd,
 					  struct pv_segment * pvseg,
 					  struct processing_handle *handle);
 
+/*
+ * Called prior to process_single_lv() to decide if the LV should be
+ * processed.  If this returns 0, the LV is not processed.
+ *
+ * This can evaluate the combination of command definition and
+ * the LV object to decide if the combination is allowed.
+ */
+typedef int (*check_single_lv_fn_t) (struct cmd_context *cmd,
+				     struct logical_volume *lv,
+				     struct processing_handle *handle,
+				     int lv_is_named_arg);
+
 int process_each_vg(struct cmd_context *cmd,
 	            int argc, char **argv,
 		    const char *one_vgname,
@@ -125,6 +137,7 @@ int process_each_segment_in_pv(struct cmd_context *cmd,
 int process_each_lv(struct cmd_context *cmd, int argc, char **argv,
 		    const char *one_vgname, const char *one_lvname,
 		    uint32_t flags, struct processing_handle *handle,
+		    check_single_lv_fn_t check_single_lv,
 		    process_single_lv_fn_t process_single_lv);
 
 
@@ -141,6 +154,7 @@ int process_each_pv_in_vg(struct cmd_context *cmd, struct volume_group *vg,
 int process_each_lv_in_vg(struct cmd_context *cmd, struct volume_group *vg,
 			  struct dm_list *arg_lvnames, const struct dm_list *tagsl,
 			  int stop_on_error, struct processing_handle *handle,
+			  check_single_lv_fn_t check_single_lv,
 			  process_single_lv_fn_t process_single_lv);
 
 struct processing_handle *init_processing_handle(struct cmd_context *cmd, struct processing_handle *parent_handle);