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|
open Core
open Yojson.Basic.Util
type expr = Term of term
| Call of reference * (term list)
| Every of (string list) * every_item * query
[@@deriving show]
and every_item = Term of term
| Call of (string list) * (term list)
[@@deriving show]
and literal = expr * (with_modifier option)
[@@deriving show]
and query = literal list
[@@deriving show]
and term = Scalar of scalar
| Var of string
| Ref of reference
| Array of term list
| Object of (object_key * term) list
| Set of term list
| ArrayComprehension of term * query
| ObjectComprehension of (object_key * term) * query
| SetComprehension of term * query
[@@deriving show]
and scalar = String of string
| Number of float
| Bool of bool
| Null
[@@deriving show]
and reference = ref_target * (ref_arg list)
[@@deriving show]
and ref_target = Var of string
| Array of term list
| Object of (object_key * term) list
| Set of term list
| ArrayComprehension of term * query
| ObjectComprehension of (object_key * term) * query
| SetComprehension of term * query
| Call of reference * (term list)
[@@deriving show]
and ref_arg = Scalar of scalar
| Var of string
| Array of term list
| Object of (object_key * term) list
| Set of term list
[@@deriving show]
and object_key = Scalar of scalar
| Ref of reference
| Var of string
[@@deriving show]
and with_modifier = (term * term)
[@@deriving show]
type assign_operator = Assign | Unify
[@@deriving show]
type rule_head_lhs = reference
[@@deriving show]
type rule_head_rhs = Assignment of assign_operator * term
| Object of term * assign_operator * term
| Function of (term list) * assign_operator * term
| Set of term
[@@deriving show]
type rule_head = rule_head_lhs * rule_head_rhs
[@@deriving show]
type rule =
{ default : bool;
head : rule_head;
body: literal list;
otherwise : rule option;
}
[@@deriving show]
type import =
{ alias : string option;
path : reference;
}
[@@deriving show]
type package =
{ path : reference;
imports: import list;
policy : rule list;
}
[@@deriving show]
let to_bool_or_false : Yojson.Basic.t -> bool = function
| `Bool b -> b
| _ -> false
let to_list_or_empty : Yojson.Basic.t -> Yojson.Basic.t list = function
| `Null -> []
| `List xs -> xs
| _ -> failwith "Not a list or null"
let object_key_of_term : term -> object_key = function
| Scalar s -> Scalar s
| Ref r -> Ref r
| Var v -> Var v
| _ -> failwith "failed to convert term to object_key"
let rec parse_term (tree : Yojson.Basic.t) : term =
Printf.printf "%s: %s\n" "parse_term" (Yojson.Basic.to_string tree);
let term_type = tree |> member "type" |> to_string in
match term_type with
| "var" -> Var (tree |> member "value" |> to_string)
| "ref" -> Ref (tree |> member "value" |> to_list |> parse_ref)
| "boolean" -> Scalar (Bool (tree |> member "value" |> to_bool))
| "number" -> Scalar (Number (tree |> member "value" |> to_number))
| "string" -> Scalar (String (tree |> member "value" |> to_string))
| "array" -> Array (tree |> member "value" |> to_list |> List.map ~f:parse_term)
| "set" -> Set (tree |> member "value" |> to_list |> List.map ~f:parse_term)
| "object" ->
Object
(tree
|> member "value"
|> to_list
|> List.map ~f:(function
| `List [x; y] ->
(x |> parse_term |> object_key_of_term, y |> parse_term)
| _ -> failwith "ill-formed object"))
| "arraycomprehension" ->
ArrayComprehension
(tree |> member "value" |> member "term" |> parse_term,
tree |> member "value" |> member "body" |> to_list |> List.map ~f:(fun x -> (parse_expr x, None)))
| "setcomprehension" ->
SetComprehension
(tree |> member "value" |> member "term" |> parse_term,
tree |> member "value" |> member "body" |> to_list |> List.map ~f:(fun x -> (parse_expr x, None)))
| "objectcomprehension" ->
ObjectComprehension
((tree |> member "value" |> member "key" |> parse_term |> object_key_of_term,
tree |> member "value" |> member "value" |> parse_term),
tree |> member "value" |> member "body" |> to_list |> List.map ~f:(fun x -> (parse_expr x, None)))
| _ -> failwith ("unsupported term type " ^ term_type)
and parse_expr tree : expr =
Printf.printf "%s: %s\n" "parse_expr" (Yojson.Basic.to_string tree);
match tree |> member "terms" with
| `List (func :: args) ->
Call (func |> member "value" |> to_list |> parse_ref,
List.map ~f:parse_term args)
| `List _ -> failwith "todo"
| x -> Term (parse_term x)
and parse_ref_target tree : ref_target =
Printf.printf "%s: %s\n" "parse_ref_target" (Yojson.Basic.to_string tree);
if String.equal (tree |> member "type" |> to_string) "call" then
match tree |> member "value" |> to_list with
| func :: args ->
Call (func |> member "value" |> to_list |> parse_ref,
List.map ~f:parse_term args)
| _ -> failwith "ill_formed call"
else
let term = parse_term tree in
match term with
| Var term -> Var term
| Array term -> Array term
| Object term -> Object term
| Set term -> Set term
| ArrayComprehension (term, y) -> ArrayComprehension (term, y)
| ObjectComprehension (term, y) -> ObjectComprehension (term, y)
| SetComprehension (term, y) -> SetComprehension (term, y)
| _ -> failwith ("unsupported ref_target " ^ (show_term term))
and parse_ref_arg tree : ref_arg =
Printf.printf "%s: %s\n" "parse_ref_arg" (Yojson.Basic.to_string tree);
let term = parse_term tree in
match term with
| Scalar x -> Scalar x
| Var x -> Var x
| Array x -> Array x
| Object x -> Object x
| Set x -> Set x
| _ -> failwith ("unsupported ref_arg " ^ (show_term term))
and parse_ref tree =
Printf.printf "%s: %s\n" "parse_ref" (String.concat (List.map ~f:Yojson.Basic.to_string tree));
match tree with
| target :: args -> (parse_ref_target target, List.map ~f:parse_ref_arg args)
| _ -> failwith "empty reference"
let parse_head tree =
Printf.printf "%s: %s\n" "parse_head" (Yojson.Basic.to_string tree);
(* Variables are desugared to empty references. *)
let lhs = tree |> member "ref" |> to_list |> parse_ref in
let rhs =
if tree |> member "assign" |> to_bool_or_false then
Assignment (Assign, (tree |> member "value" |> parse_term))
(* TODO: Rest cases? *)
else
Assignment (Unify, (tree |> member "value" |> parse_term))
in (lhs, rhs)
let rec parse_rule tree =
Printf.printf "%s: %s\n" "rec parse_rule tree" (Yojson.Basic.to_string tree);
{ default = tree |> member "default" |> to_bool_or_false;
head = tree |> member "head" |> parse_head;
body = List.map ~f:(fun x -> ((parse_expr x, None) : literal)) (tree |> member "body" |> to_list_or_empty);
otherwise =
match tree |> member "else" with
| `Null -> None
| else_branch -> Some (parse_rule else_branch)
}
(* --- *)
let parse_import_path tree =
Printf.printf "%s: %s\n" "parse_import_path" (Yojson.Basic.to_string tree);
match (tree |> member "type" |> to_string) with
| "ref" -> tree |> member "value" |> to_list |> parse_ref
| _ -> failwith "unimplemented"
let parse_import tree =
Printf.printf "%s: %s\n" "parse_import" (Yojson.Basic.to_string tree);
{ alias = tree |> member "alias" |> to_string_option;
path = tree |> member "path" |> parse_import_path
}
(* --- *)
let parse_package tree =
Printf.printf "%s: %s\n" "parse_package" (Yojson.Basic.to_string tree);
tree |> member "path" |> to_list |> parse_ref
(* --- *)
let parse_tree tree =
Printf.printf "%s: %s\n" "parse_tree" (Yojson.Basic.to_string tree);
{ path = tree |> member "package" |> parse_package;
imports = List.map ~f:parse_import (tree |> member "imports" |> to_list_or_empty);
policy = List.map ~f:parse_rule (tree |> member "rules" |> to_list_or_empty)
}
let invoke ?(stdin="") ?(env=[| |]) cmd =
let ic, oc, ec = UnixLabels.open_process_full cmd ~env:env in
Out_channel.output_string oc stdin ;
Out_channel.close oc;
(In_channel.input_all ic,
In_channel.input_all ec)
let () =
let file_name = Array.get (Sys.get_argv ()) 1 in
let policy_code = In_channel.read_all file_name in
let (stdout, _) = invoke ("/home/jakob/.local/bin/opa parse -f json /dev/stdin") ~stdin:policy_code ~env:[| |] in
Yojson.Basic.from_string stdout |> parse_tree |> show_package |> print_endline
|
