From f3a76cde5d6a6a1cfbcf10e406de7e424c23520f Mon Sep 17 00:00:00 2001 From: ahgamut <41098605+ahgamut@users.noreply.github.com> Date: Wed, 13 Jul 2022 13:06:41 +0530 Subject: [PATCH] make ljson more strict - add new context ARRAY_SINGLE for [singleton] without commas - add new context ARRAY_END for [] without commas - add new context OBJECT_END for {} without commas - call Parse() once before looping for array or object so that the empty case is handled easily ([,] should now be wrong) - narrow use of OBJECT_KEY -- now it is only used to confirm that the key is a string - rename ARRAY_VAL to AFTER_VALUE -- a comma will only be present after a value ie either [1,2] or {"a":1,"b":2}, so the context for comma is always after value - reset context when AFTER_VALUE and OBJECT_VAL to avoid extra ,: - use bitfields instead of equality to check the context value - TOP_LEVEL is used to define the maximum depth, and now the depth is compared to TOP_LEVEL for the base case --- tool/net/ljson.c | 50 ++++++++++++++++++++++++++++-------------------- 1 file changed, 29 insertions(+), 21 deletions(-) diff --git a/tool/net/ljson.c b/tool/net/ljson.c index 5e46318aa..46260312f 100644 --- a/tool/net/ljson.c +++ b/tool/net/ljson.c @@ -31,10 +31,14 @@ #include "third_party/lua/lua.h" #include "tool/net/ljson.h" -#define TOP_LEVEL 0 -#define ARRAY_VAL 1 -#define OBJECT_KEY 2 -#define OBJECT_VAL 3 +#define AFTER_VALUE 0x01u +#define ARRAY_SINGLE 0x02u +#define ARRAY_END 0x04u +#define OBJECT_KEY 0x10u +#define OBJECT_VAL 0x20u +#define OBJECT_END 0x40u + +#define TOP_LEVEL 64 static struct DecodeJson Parse(struct lua_State *L, const char *p, const char *e, int context, int depth) { @@ -58,7 +62,8 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, break; case ',': // present in list and object - if (context == ARRAY_VAL || context == OBJECT_KEY) { + if (0 != (context & AFTER_VALUE)) { + context = 0; a = p; break; } else { @@ -66,7 +71,8 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, } case ':': // present only in object after key - if (context == OBJECT_VAL) { + if (0 != (context & OBJECT_VAL)) { + context = 0; a = p; break; } else { @@ -74,7 +80,7 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, } case 'n': // null - if (UNLIKELY(context == OBJECT_KEY)) goto BadObjectKey; + if (UNLIKELY(0 != (context & OBJECT_KEY))) goto BadObjectKey; if (p + 3 <= e && READ32LE(p - 1) == READ32LE("null")) { lua_pushnil(L); return (struct DecodeJson){1, p + 3}; @@ -83,7 +89,7 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, } case 'f': // false - if (UNLIKELY(context == OBJECT_KEY)) goto BadObjectKey; + if (UNLIKELY(0 != (context & OBJECT_KEY))) goto BadObjectKey; if (p + 4 <= e && READ32LE(p) == READ32LE("alse")) { lua_pushboolean(L, false); return (struct DecodeJson){1, p + 4}; @@ -92,7 +98,7 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, } case 't': // true - if (UNLIKELY(context == OBJECT_KEY)) goto BadObjectKey; + if (UNLIKELY(0 != (context & OBJECT_KEY))) goto BadObjectKey; if (p + 3 <= e && READ32LE(p - 1) == READ32LE("true")) { lua_pushboolean(L, true); return (struct DecodeJson){1, p + 3}; @@ -104,7 +110,7 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, return (struct DecodeJson){-1, "object key must be string"}; case '-': // negative - if (UNLIKELY(context == OBJECT_KEY)) goto BadObjectKey; + if (UNLIKELY(0 != (context & OBJECT_KEY))) goto BadObjectKey; if (p < e && isdigit(*p)) { d = -1; break; @@ -113,7 +119,7 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, } case '0': // zero or number - if (UNLIKELY(context == OBJECT_KEY)) goto BadObjectKey; + if (UNLIKELY(0 != (context & OBJECT_KEY))) goto BadObjectKey; if (p < e) { if ((*p == '.' || *p == 'e' || *p == 'E')) { goto UseDubble; @@ -125,7 +131,7 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, return (struct DecodeJson){1, p}; case '1' ... '9': // integer - if (UNLIKELY(context == OBJECT_KEY)) goto BadObjectKey; + if (UNLIKELY(0 != (context & OBJECT_KEY))) goto BadObjectKey; for (x = (c - '0') * d; p < e; ++p) { c = *p & 255; if (isdigit(c)) { @@ -148,11 +154,11 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, return (struct DecodeJson){1, a + c}; case '[': // Array - if (UNLIKELY(context == OBJECT_KEY)) goto BadObjectKey; + if (UNLIKELY(0 != (context & OBJECT_KEY))) goto BadObjectKey; lua_newtable(L); i = 0; + r = Parse(L, p, e, ARRAY_SINGLE | ARRAY_END, depth - 1); for (;;) { - r = Parse(L, p, e, ARRAY_VAL, depth - 1); if (UNLIKELY(r.rc == -1)) { lua_pop(L, 1); return r; @@ -162,6 +168,7 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, break; } lua_rawseti(L, -2, i++ + 1); + r = Parse(L, p, e, AFTER_VALUE | ARRAY_END, depth - 1); } if (!i) { // we need this kludge so `[]` won't round-trip as `{}` @@ -171,24 +178,24 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, return (struct DecodeJson){1, p}; case ']': - if (context == ARRAY_VAL) { + if (0 != (context & ARRAY_END)) { return (struct DecodeJson){0, p}; } else { return (struct DecodeJson){-1, "unexpected ']'"}; } case '}': - if (context == OBJECT_KEY) { + if (0 != (context & OBJECT_END)) { return (struct DecodeJson){0, p}; } else { return (struct DecodeJson){-1, "unexpected '}'"}; } case '{': // Object - if (UNLIKELY(context == OBJECT_KEY)) goto BadObjectKey; + if (UNLIKELY(0 != (context & OBJECT_KEY))) goto BadObjectKey; lua_newtable(L); + r = Parse(L, p, e, OBJECT_KEY | OBJECT_END, depth - 1); for (;;) { - r = Parse(L, p, e, OBJECT_KEY, depth - 1); if (r.rc == -1) { lua_pop(L, 1); return r; @@ -208,6 +215,7 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, } p = r.p; lua_settable(L, -3); + r = Parse(L, p, e, OBJECT_KEY | AFTER_VALUE | OBJECT_END, depth - 1); } return (struct DecodeJson){1, p}; @@ -355,7 +363,7 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, return (struct DecodeJson){-1, "illegal character"}; } } - if (UNLIKELY(context == TOP_LEVEL)) { + if (UNLIKELY(depth == TOP_LEVEL)) { return (struct DecodeJson){0, 0}; } else { return (struct DecodeJson){-1, "unexpected eof"}; @@ -386,10 +394,10 @@ static struct DecodeJson Parse(struct lua_State *L, const char *p, * @return r.p is string describing error if `rc < 0` */ struct DecodeJson DecodeJson(struct lua_State *L, const char *p, size_t n) { - int depth = 64; + int depth = TOP_LEVEL; if (n == -1) n = p ? strlen(p) : 0; if (lua_checkstack(L, depth * 4)) { - return Parse(L, p, p + n, TOP_LEVEL, depth); + return Parse(L, p, p + n, 0, depth); } else { return (struct DecodeJson){-1, "can't set stack depth"}; }