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Merged
membphis merged 1 commit into from
May 31, 2026
Merged

feat: add contextual qjson errors #127

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4 changes: 4 additions & 0 deletions include/qjson.h
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Original file line number Diff line number Diff line change
Expand Up @@ -63,6 +63,10 @@ typedef struct {
} qjson_iter;

const char* qjson_strerror(int code);
size_t qjson_format_error(int code, size_t offset, size_t extra,
const char* buf, size_t buf_len,
char* out, size_t out_len);
size_t qjson_doc_last_error_offset(const qjson_doc* doc);

qjson_doc* qjson_parse(const uint8_t* buf, size_t len, qjson_error* err_out);
qjson_doc* qjson_parse_ex(const uint8_t* buf, size_t len,
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101 changes: 71 additions & 30 deletions lua/qjson.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -42,28 +42,68 @@ _M.ERR = ERR
local Doc = {}; Doc.__index = Doc
local Cursor = {}; Cursor.__index = Cursor

local function check_err(rc)
local MODE_EAGER = 0
local MODE_LAZY = 1
local DEFAULT_MAX_DEPTH = 1024
local MAX_MAX_DEPTH = 4096
local SIZE_MAX = ffi.cast("size_t", -1)
local EXPECT_CONTAINER = ffi.cast("size_t", -2)

local function extra_or_none(extra)
if extra == nil then return SIZE_MAX end
return extra
end

local function format_error(code, offset, extra, buf)
local buf_len = 0
if type(buf) == "string" then
buf_len = #buf
else
buf = nil
end
extra = extra_or_none(extra)
local needed = tonumber(C.qjson_format_error(code, offset, extra, buf, buf_len, nil, 0))
local out = ffi.new("char[?]", needed + 1)
local written = tonumber(C.qjson_format_error(code, offset, extra, buf, buf_len, out, needed + 1))
return ffi.string(out, written)
end

local function check_access(doc, rc, expected_type)
if rc == 0 then return true end
if rc == NOT_FOUND then return false end
error("qjson: " .. ffi.string(C.qjson_strerror(rc)))
local offset = SIZE_MAX
local source = nil
if doc and doc._ptr ~= nil then
offset = C.qjson_doc_last_error_offset(doc._ptr)
source = doc._hold
end
local msg = format_error(rc, offset, expected_type, source)
error("qjson: " .. msg)
end

local opts_box = ffi.new("qjson_options[1]")

local MODE_EAGER = 0
local MODE_LAZY = 1
local SIZE_MAX = ffi.cast("size_t", -1)
local function effective_max_depth(raw)
if raw == 0 then
return DEFAULT_MAX_DEPTH
end
if raw > MAX_MAX_DEPTH then
return MAX_MAX_DEPTH
end
return raw
end

local function parse_error_message(err)
local msg = ffi.string(C.qjson_strerror(err.code))
if err.offset ~= SIZE_MAX then
msg = msg .. " at byte " .. tostring(tonumber(err.offset))
local function parse_error_message(err, json_str, max_depth)
local extra
if err.code == ERR.NESTING_TOO_DEEP then
extra = max_depth or DEFAULT_MAX_DEPTH
end
return msg
return format_error(err.code, err.offset, extra, json_str)
end

function _M.parse(json_str, opts)
local ptr
local effective_depth = DEFAULT_MAX_DEPTH
if opts == nil then
ptr = C.qjson_parse(json_str, #json_str, err_box)
else
Expand All @@ -78,12 +118,13 @@ function _M.parse(json_str, opts)
if type(max_depth) ~= "number" or max_depth < 0 or max_depth ~= math.floor(max_depth) then
error("qjson.parse: opts.max_depth must be a non-negative integer")
end
effective_depth = effective_max_depth(max_depth)
opts_box[0].mode = lazy and MODE_LAZY or MODE_EAGER
opts_box[0].max_depth = max_depth
ptr = C.qjson_parse_ex(json_str, #json_str, opts_box, err_box)
end
if ptr == nil then
error("qjson: " .. parse_error_message(err_box[0]))
error("qjson: " .. parse_error_message(err_box[0], json_str, effective_depth))
end
return setmetatable({
_ptr = ffi.gc(ptr, C.qjson_free),
Expand All @@ -93,122 +134,122 @@ end

function Doc:get_str(path)
local rc = C.qjson_get_str(self._ptr, path, #path, strp_box, size_box)
if not check_err(rc) then return nil end
if not check_access(self, rc, _M.T_STR) then return nil end
return ffi.string(strp_box[0], size_box[0])
end

function Doc:get_i64(path)
local rc = C.qjson_get_i64(self._ptr, path, #path, i64_box)
if not check_err(rc) then return nil end
if not check_access(self, rc, _M.T_NUM) then return nil end
return i64_box[0]
end

function Doc:get_u64(path)
local rc = C.qjson_get_u64(self._ptr, path, #path, u64_box)
if not check_err(rc) then return nil end
if not check_access(self, rc, _M.T_NUM) then return nil end
return u64_box[0]
end

function Doc:get_f64(path)
local rc = C.qjson_get_f64(self._ptr, path, #path, f64_box)
if not check_err(rc) then return nil end
if not check_access(self, rc, _M.T_NUM) then return nil end
return f64_box[0]
end

function Doc:get_bool(path)
local rc = C.qjson_get_bool(self._ptr, path, #path, bool_box)
if not check_err(rc) then return nil end
if not check_access(self, rc, _M.T_BOOL) then return nil end
return bool_box[0] ~= 0
end

function Doc:is_null(path)
local rc = C.qjson_is_null(self._ptr, path, #path, bool_box)
if not check_err(rc) then return nil end
if not check_access(self, rc) then return nil end
return bool_box[0] ~= 0
end

function Doc:typeof(path)
local rc = C.qjson_typeof(self._ptr, path, #path, type_box)
if not check_err(rc) then return nil end
if not check_access(self, rc) then return nil end
return type_box[0]
end

function Doc:len(path)
local rc = C.qjson_len(self._ptr, path, #path, size_box)
if not check_err(rc) then return nil end
if not check_access(self, rc, EXPECT_CONTAINER) then return nil end
return tonumber(size_box[0])
end

function Doc:open(path)
local rc = C.qjson_open(self._ptr, path, #path, cur_box)
if not check_err(rc) then return nil end
if not check_access(self, rc) then return nil end
return setmetatable({ _cur = cur_box[0], _doc = self }, Cursor)
end

function Cursor:get_str(path)
path = path or ""
local rc = C.qjson_cursor_get_str(self._cur, path, #path, strp_box, size_box)
if not check_err(rc) then return nil end
if not check_access(self._doc, rc, _M.T_STR) then return nil end
return ffi.string(strp_box[0], size_box[0])
end

function Cursor:get_i64(path)
path = path or ""
local rc = C.qjson_cursor_get_i64(self._cur, path, #path, i64_box)
if not check_err(rc) then return nil end
if not check_access(self._doc, rc, _M.T_NUM) then return nil end
return i64_box[0]
end

function Cursor:get_u64(path)
path = path or ""
local rc = C.qjson_cursor_get_u64(self._cur, path, #path, u64_box)
if not check_err(rc) then return nil end
if not check_access(self._doc, rc, _M.T_NUM) then return nil end
return u64_box[0]
end

function Cursor:get_f64(path)
path = path or ""
local rc = C.qjson_cursor_get_f64(self._cur, path, #path, f64_box)
if not check_err(rc) then return nil end
if not check_access(self._doc, rc, _M.T_NUM) then return nil end
return f64_box[0]
end

function Cursor:get_bool(path)
path = path or ""
local rc = C.qjson_cursor_get_bool(self._cur, path, #path, bool_box)
if not check_err(rc) then return nil end
if not check_access(self._doc, rc, _M.T_BOOL) then return nil end
return bool_box[0] ~= 0
end

function Cursor:typeof(path)
path = path or ""
local rc = C.qjson_cursor_typeof(self._cur, path, #path, type_box)
if not check_err(rc) then return nil end
if not check_access(self._doc, rc) then return nil end
return type_box[0]
end

function Cursor:len(path)
path = path or ""
local rc = C.qjson_cursor_len(self._cur, path, #path, size_box)
if not check_err(rc) then return nil end
if not check_access(self._doc, rc, EXPECT_CONTAINER) then return nil end
return tonumber(size_box[0])
end

function Cursor:open(path)
local rc = C.qjson_cursor_open(self._cur, path, #path, cur_box)
if not check_err(rc) then return nil end
if not check_access(self._doc, rc) then return nil end
return setmetatable({ _cur = cur_box[0], _doc = self._doc }, Cursor)
end

function Cursor:field(key)
local rc = C.qjson_cursor_field(self._cur, key, #key, cur_box)
if not check_err(rc) then return nil end
if not check_access(self._doc, rc, _M.T_OBJ) then return nil end
return setmetatable({ _cur = cur_box[0], _doc = self._doc }, Cursor)
end

function Cursor:index(i)
local rc = C.qjson_cursor_index(self._cur, i, cur_box)
if not check_err(rc) then return nil end
if not check_access(self._doc, rc, _M.T_ARR) then return nil end
return setmetatable({ _cur = cur_box[0], _doc = self._doc }, Cursor)
end

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6 changes: 6 additions & 0 deletions lua/qjson/lib.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,10 @@ typedef struct {
} qjson_options;

const char* qjson_strerror(int code);
size_t qjson_format_error(int code, size_t offset, size_t extra,
const char* buf, size_t buf_len,
char* out, size_t out_len);
size_t qjson_doc_last_error_offset(const qjson_doc* doc);
qjson_doc* qjson_parse (const uint8_t* buf, size_t len, qjson_error* err_out);
qjson_doc* qjson_parse_ex(const uint8_t* buf, size_t len,
const qjson_options* opts, qjson_error* err_out);
Expand Down Expand Up @@ -63,6 +67,8 @@ local attempts = {}
local last_error
local required_symbols = {
"qjson_strerror",
"qjson_format_error",
"qjson_doc_last_error_offset",
"qjson_parse",
"qjson_parse_ex",
"qjson_free",
Expand Down
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