Merge pull request #68 from jestabro/mask-exclusive

T8488: add mask exclusive and supporting utilitlies

1 files changed, 102 insertions, 4 deletions

diff --git a/src/config_diff.ml b/src/config_diff.ml
index 5d71c34..c00705d 100644
--- a/src/config_diff.ml
+++ b/src/config_diff.ml
@@ -706,7 +706,7 @@ let diff_show rt path left right =
         diff_show_result.config_diff
 
 (* mask function; mask applied on right *)
-let mask_func ?recurse:_ (path : string list) (Diff_tree res) (m : change) =
+let mask_func_inclusive ?recurse:_ (path : string list) (Diff_tree res) (m : change) =
     (* alert exn Vytree.delete:
         [Vytree.Empty_path] not possible since Unchanged pattern is only empty path
         [Vytree.Nonexistent_path] not possible as called on existing config paths (res.left)
@@ -716,18 +716,43 @@ let mask_func ?recurse:_ (path : string list) (Diff_tree res) (m : change) =
     match m with
     | Added -> Diff_tree (res)
     | Subtracted ->
-            (match path with
+        begin
+            match path with
             | [_] ->
                 Diff_tree {res with left = (Vytree.delete[@alert "-exn"]) res.left path}
             |  _  ->
                 if not ((Vytree.is_terminal_path[@alert "-exn"]) res.right (list_but_last path)) then
                     Diff_tree {res with left = (Vytree.delete[@alert "-exn"]) res.left path}
-                else Diff_tree (res))
+                else Diff_tree (res)
+        end
     | Unchanged -> Diff_tree (res)
     | Updated _ -> Diff_tree (res)
 
+(* mask function; mask applied on right *)
+let mask_func_exclusive ?recurse:_ (path : string list) (Diff_tree res) (m : change) =
+    (* alert exn Vytree.delete:
+        [Vytree.Empty_path] not possible in pattern match case
+        [Vytree.Nonexistent_path] not possible as called on existing config paths (res.left)
+       alert exn Vytree.is_terminal_path:
+        [Vytree.Empty_path] not possible in pattern match case
+     *)
+    match m with
+    | Added -> Diff_tree (res)
+    | Subtracted -> Diff_tree (res)
+    | Unchanged | Updated _ ->
+        begin
+            match path with
+            | [] -> Diff_tree(res)
+            | _ ->
+                if ((Vytree.is_terminal_path[@alert "-exn"]) res.right path) then
+                    let tmp = (Vytree.delete[@alert "-exn"]) res.left path in
+                    let left' = (Config_tree.prune_delete[@alert "-exn"]) tmp path in
+                    Diff_tree {res with left = left'}
+                else Diff_tree (res)
+        end
+
 (* call recursive diff with mask_func; mask applied on right *)
-let mask_tree left right =
+let mask_tree ?(exclusive=false) left right =
     (* raises:
         [Empty_comparison] from diff
         [Incommensurable]
@@ -736,11 +761,84 @@ let mask_tree left right =
         raise Incommensurable
     else
     let trees = make_diff_trees left right in
+    let mask_func =
+        if exclusive then mask_func_exclusive else mask_func_inclusive
+    in
     let d = diff [] mask_func trees (Option.some left, Option.some right)
     in
     let res = eval_diff_result d in
     res.left
 
+(* Convert from a path that may or may not include intervening tag_values,
+   returning a subtree of matches *)
+exception Malformed_path of string
+
+let subtree_from_partial reftree ctree result path =
+    if Util.is_empty path then result
+    else
+    let check_reftree p =
+        match p with
+        | [] -> false
+        | _ ->
+            let rpath =
+                Reference_tree.refpath_from_partial reftree p
+            in
+            match rpath with
+            | [] -> false
+            | _ -> true
+    in
+    let check_ctree p =
+        match p with
+        | [] -> false
+        | _ -> (Vytree.exists[@alert "-exn"]) ctree p
+    in
+    let clone_node tree p =
+        if (Vytree.exists[@alert "-exn"]) tree p then
+            tree
+        else
+        if not ((Vytree.exists[@alert "-exn"]) ctree p) then
+            tree
+        else
+            clone ~recurse:false ctree tree p
+    in
+    let clone_children tree p =
+        let children = Vytree.list_children ((Vytree.get[@alert "-exn"]) ctree p) in
+        let paths = List.map (fun n -> p @ [n]) children in
+        List.fold_left clone_node tree paths
+    in
+    let rec aux acc path_done p =
+        if not (check_reftree (path_done @ p)) then
+            raise (Malformed_path (Util.string_of_list (path_done @ p)))
+        else
+        match path_done, p with
+        | [], h :: tl ->
+                if check_reftree [h] then aux (clone_node acc [h]) [h] tl
+                else
+                raise (Malformed_path (Util.string_of_list p))
+        | _, h :: tl ->
+                let p' = path_done @ [h] in
+                if check_ctree p' then aux (clone_node acc p') p' tl
+                else
+                    if (Config_tree.is_tag[@alert "-exn"]) ctree path_done then
+                    let children =
+                        Vytree.list_children ((Vytree.get[@alert "-exn"]) ctree path_done)
+                    in
+                    let func accum child =
+                        let path = path_done @ [child] @ [h] in
+                        if check_ctree path then
+                            aux (clone_node accum path) path tl
+                        else accum
+                    in
+                    List.fold_left func acc children
+                else
+                (* [h] is a tag_value not present in the config tree *)
+                raise (Malformed_path (Util.string_of_list p'))
+        | _, [] ->
+                if (Config_tree.is_tag[@alert "-exn"]) ctree path_done then clone_children acc path_done
+                else acc
+    in aux result [] path
+
+
 let union_of_values (n : Config_tree.t) (m : Config_tree.t) =
     let set_n = ValueS.of_list (data_of n).values in
     let set_m = ValueS.of_list (data_of m).values in