Add Config_tree.render_at_level function for correct rendering of configs for human consumption.

The idea of the correct (for subsequent parsing) and familiar for all other purposes rendering:
* When rendering the entire config, do not render the invisible "root" node, only render its children.
* When rendering config at specified path, do not include any nodes that are within the path
  (e.g. if path "system login" exists, "show system" request output should start with "login {",
   not "system { login { ...").

3 files changed, 58 insertions, 4 deletions

diff --git a/src/config_tree.ml b/src/config_tree.ml
index 9fed465..c816d65 100644
--- a/src/config_tree.ml
+++ b/src/config_tree.ml
@@ -156,7 +156,7 @@ struct
 
     let render
             ?(indent=4)
-            ?(reftree)
+            ?(reftree=None)
             ?(cmp=BatString.numeric_compare)
             ?(showephemeral=false)
             ?(showinactive=false)
@@ -249,3 +249,20 @@ struct
 end (* Renderer *)
 
 let render = Renderer.render
+
+let render_at_level
+  ?(indent=4)
+  ?(reftree=None)
+  ?(cmp=BatString.numeric_compare)
+  ?(showephemeral=false)
+  ?(showinactive=false)
+  node
+  path =
+    let node = 
+        match path with
+        | [] -> node
+        | _ -> Vytree.get node path
+    in
+    let children = Vytree.children_of_node node in
+    let child_configs = List.map (render ~indent:indent ~reftree:reftree  ~cmp:cmp ~showephemeral:showephemeral ~showinactive:showinactive) children in
+    List.fold_left (Printf.sprintf "%s\n%s") "" child_configs
diff --git a/src/config_tree.mli b/src/config_tree.mli
index f724df1..f72eda9 100644
--- a/src/config_tree.mli
+++ b/src/config_tree.mli
@@ -56,10 +56,20 @@ val is_ephemeral : t -> string list -> bool
 *)
 val render :
     ?indent:int ->
-    ?reftree:Reference_tree.t ->
+    ?reftree:(Reference_tree.t option)->
     ?cmp:(string -> string -> int) ->
     ?showephemeral:bool ->
     ?showinactive:bool ->
     t ->
     string
 
+val render_at_level :
+    ?indent:int ->
+    ?reftree:(Reference_tree.t option)->
+    ?cmp:(string -> string -> int) ->
+    ?showephemeral:bool ->
+    ?showinactive:bool ->
+    t ->
+    string list ->
+    string
+
diff --git a/test/config_tree_test.ml b/test/config_tree_test.ml
index ad79df3..be8b320 100644
--- a/test/config_tree_test.ml
+++ b/test/config_tree_test.ml
@@ -153,13 +153,38 @@ let test_render_ephemeral_shown teset_ctxt =
     }
 }"
 
+let test_render_at_level test_ctxt =
+    let path = ["foo"; "bar"; "baz"] in
+    let node = CT.make "root" in
+    let node = CT.set node path (Some "quux") CT.AddValue in
+    let rendered = CT.render_at_level node ["foo"] in
+    assert_equal (String.trim rendered)
+"bar {
+    baz \"quux\";
+}"
+
+let test_render_at_level_top test_ctxt =
+    let path1 = ["foo"; "bar"] in
+    let path2 = ["baz"; "quux"] in
+    let node = CT.make "root" in
+    let node = CT.set node path1 (Some "quuux") CT.AddValue in
+    let node = CT.set node path2 (Some "xyzzy") CT.AddValue in
+    let rendered = CT.render_at_level node [] in
+    assert_equal (String.trim rendered)
+"baz {
+    quux \"xyzzy\";
+}
+foo {
+    bar \"quuux\";
+}"
+
 (**** Reftree-based rendering *)
 let test_render_rt_tag_node test_ctxt =
     let reftree = load_reftree test_ctxt in
     let path = ["system"; "login"; "user"; "full-name"] in
     let node = CT.make "root" in
     let node = CT.set node path (Some "name here") CT.AddValue in
-    let rendered_curly_config = CT.render ~reftree node in
+    let rendered_curly_config = CT.render ~reftree:(Some reftree) node in
     let desired_rendered_form =
 "root {
     system {
@@ -176,7 +201,7 @@ let test_render_rt_unspecified_node test_ctxt =
     let path = ["system"; "login"; "user"; "unspecified_node"] in
     let node = CT.make "root" in
     let node = CT.set node path (Some "name here") CT.AddValue in
-    let rendered_curly_config = CT.render ~reftree node in
+    let rendered_curly_config = CT.render ~reftree:(Some reftree) node in
     let desired_rendered_form =
 "root {
     system {
@@ -204,6 +229,8 @@ let suite =
         "test_render_nested_empty_with_comment" >:: test_render_nested_empty_with_comment;
         "test_render_ephemeral_hidden " >:: test_render_ephemeral_hidden;
         "test_render_ephemeral_shown"  >:: test_render_ephemeral_shown;
+        "test_render_at_level" >:: test_render_at_level;
+        "test_render_at_level_top" >:: test_render_at_level_top;
         "test_render_rt_tag_node" >:: test_render_rt_tag_node;
         "test_render_rt_unspecified_node" >:: test_render_rt_unspecified_node
     ]