From 6ac2377bfab981b3251afbae1be39645a4aadb0c Mon Sep 17 00:00:00 2001
From: Prashanth Mundkur <prashanth.mundkur@citrix.com>
Date: Fri, 20 Mar 2009 15:01:37 -0700
Subject: [PATCH] [json] Generate errors for trailing comma in array, and for
 unterminated values.

---
 libs/json/json_parse.ml  | 49 +++++++++++++++++++++++++++++++++-------
 libs/json/json_parse.mli |  1 +
 2 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/libs/json/json_parse.ml b/libs/json/json_parse.ml
index d4fa2f9..e36ca4e 100644
--- a/libs/json/json_parse.ml
+++ b/libs/json/json_parse.ml
@@ -15,6 +15,7 @@
 
 type cursor =
 	| Start
+	| Expect_value
 	| In_null of int
 	| In_true of int
 	| In_false of int
@@ -29,7 +30,6 @@ type cursor =
 	| Expect_object_elem_colon
 	| Expect_comma_or_end
 	| Expect_object_key
-	| Error
 	| Done of Json.t
 
 type int_value =
@@ -69,6 +69,16 @@ let ivalue_to_str = function
 	| IObject_needs_value _ -> "object_needing_value"
 	| IArray _ -> "array"
 
+let current_cursor_value = function
+	| Start	| Expect_value -> "value"
+	| In_null _ -> "null"
+	| In_true _ | In_false _ -> "boolean"
+	| In_int _ | In_float _ | In_int_exp _ | In_float_exp _	 -> "number"
+	| In_string _ | In_string_control _ | In_string_hex _ -> "string"
+	| Expect_object_elem_start | Expect_object_elem_colon | Expect_object_key -> "object"
+	| Expect_comma_or_end -> "object/array"
+	| Done _ -> ""
+
 let is_space c = c = ' ' || c = '\t' || c = '\n' || c = '\r'
 
 let is_hex_char = function
@@ -94,6 +104,7 @@ let clist_to_string cs =
 
 exception Unexpected_char of char * (* json type *) string
 exception Invalid_value of (* value *) string * (* json type *) string
+exception Unterminated_value of string
 exception Internal_error of string
 
 let finish_value s v =
@@ -128,6 +139,7 @@ let pop_stack s =
 		raise (Internal_error "empty stack at pop_stack")
 
 let rec parse_char s c =
+	(* Printf.printf "parsing %C at %s...\n" c (current_cursor_value s.cursor); *)
 	let finish_int is =
 		let str = clist_to_string (List.rev is) in
 		let int = try Int64.of_string str
@@ -182,6 +194,27 @@ let rec parse_char s c =
 			()
 		 | _ ->
 			raise (Unexpected_char (c, "start")))
+	| Expect_value ->
+		(match c with
+		 | 'n' ->
+			s.cursor <- In_null 3
+		 | 't' ->
+			s.cursor <- In_true 3
+		 | 'f' ->
+			s.cursor <- In_false 4
+		 | '-' | '0' .. '9' ->
+			s.cursor <- In_int [c]
+		 | '"' ->
+			s.cursor <- In_string []
+		 | '{' ->
+			s.cursor <- Expect_object_elem_start
+		 | '[' ->
+			s.stack	 <- (IArray []) :: s.stack;
+			s.cursor <- Start
+		 | _ when is_space c ->
+			()
+		 | _ ->
+			raise (Unexpected_char (c, "value")))
 	| In_null rem ->
 		(match c, rem with
 		 | 'u', 3 ->
@@ -323,7 +356,7 @@ let rec parse_char s c =
 		(match c with
 		 | ',' ->
 			if is_parsing_object s then s.cursor <- Expect_object_key
-			else s.cursor <- Start
+			else s.cursor <- Expect_value
 		 | '}' ->
 			if is_parsing_object s then pop_stack s
 			else raise (Unexpected_char (c, "comma_or_end"))
@@ -346,8 +379,6 @@ let rec parse_char s c =
 			()
 		 | _ ->
 			raise (Unexpected_char (c, "object_key")))
-	| Error ->
-		()
 	| Done _ ->
 		raise (Internal_error "parse called when parse_state is 'Done'")
 
@@ -361,13 +392,13 @@ let call_parser state str =
 	let i = ref 0 in
 	while get_parse_result state = None && !i < len do
 		parse_char state str.[!i];
-	  	(* This is here instead of inside parse_char since
+		(* This is here instead of inside parse_char since
 		   parse_char makes (tail-)recursive calls without
 		   consuming a character.
 		*)
-	  	state.num_chars_parsed <- state.num_chars_parsed + 1;
+		state.num_chars_parsed <- state.num_chars_parsed + 1;
 
-	    	incr i
+		incr i
 	done;
 	match get_parse_result state with
 	| Some v -> Json_value (v, (String.sub str !i (len - !i)))
@@ -386,6 +417,8 @@ let parse state str =
 let finish_parse state =
 	match parse state " " with
 	| Json_value (v, _) -> Some v
-	| Json_parse_incomplete _ -> None
+	| Json_parse_incomplete _ ->
+		if state.cursor = Start then None
+		else raise (Unterminated_value (current_cursor_value state.cursor))
 
 let num_chars_parsed state = state.num_chars_parsed
diff --git a/libs/json/json_parse.mli b/libs/json/json_parse.mli
index 89af20b..e881d8c 100644
--- a/libs/json/json_parse.mli
+++ b/libs/json/json_parse.mli
@@ -29,4 +29,5 @@ val num_chars_parsed: parse_state -> int
 
 exception Unexpected_char of char * (* json type *) string
 exception Invalid_value of (* value *) string * (* json type *) string
+exception Unterminated_value of string
 exception Internal_error of string
-- 
2.39.5