Add value retrieval functions to the session module.

1 files changed, 28 insertions, 0 deletions

diff --git a/src/session.ml b/src/session.ml
index cc71116..b5492ea 100644
--- a/src/session.ml
+++ b/src/session.ml
@@ -2,6 +2,8 @@ module CT = Config_tree
 module RT = Reference_tree
 module D = Directories
 
+exception Session_error of string
+
 type cfg_op =
     | CfgSet of string list * string option * CT.value_behaviour
     | CfgDelete of string list * string	option
@@ -53,3 +55,29 @@ let delete w s path =
     let op = CfgDelete (path, value) in
     let config = apply_cfg_op op s.proposed_config in
     {s with proposed_config=config; changeset=(op :: s.changeset)}
+
+let get_value w s path =
+    let path, _ = RT.validate_path D.(w.dirs.validators) w.reference_tree path in
+    if RT.is_leaf w.reference_tree path then
+        if not ((RT.is_multi w.reference_tree path) || (RT.is_valueless w.reference_tree path))
+        then CT.get_value s.proposed_config path
+        else raise (Session_error "This node can have more than one value")
+    else raise (Session_error "Cannot get a value of a non-leaf node")
+
+let get_values w s path =
+    let path, _ = RT.validate_path D.(w.dirs.validators) w.reference_tree path in
+    if RT.is_leaf w.reference_tree path then
+        if RT.is_multi w.reference_tree path
+        then CT.get_values s.proposed_config path
+        else raise (Session_error "This node can have only one value")
+    else raise (Session_error "Cannot get a value of a non-leaf node")
+
+let list_children w s path =
+    let path, _ = RT.validate_path D.(w.dirs.validators) w.reference_tree path in
+    if not (RT.is_leaf w.reference_tree path)
+    then Vytree.children_of_path s.proposed_config path
+    else raise (Session_error "Cannot list children of a leaf node")
+
+let exists w s path =
+    let path, _ = RT.validate_path D.(w.dirs.validators) w.reference_tree path in
+    Vytree.exists s.proposed_config path