jsonfly.nvim/lua/jsonfly/json.lua

local VERSION = "20161109.21" -- version history at end of file
local AUTHOR_NOTE = "-[ JSON.lua package by Jeffrey Friedl (http://regex.info/blog/lua/json) version 20161109.21 ]-"

local OBJDEF = {
	VERSION = VERSION,
	AUTHOR_NOTE = AUTHOR_NOTE,
}

local default_pretty_indent = "  "
local default_pretty_options = { pretty = true, align_keys = false, indent = default_pretty_indent }

local isArray = {
	__tostring = function()
		return "JSON array"
	end,
}
isArray.__index = isArray
local isObject = {
	__tostring = function()
		return "JSON object"
	end,
}
isObject.__index = isObject

function OBJDEF:newArray(tbl)
	return setmetatable(tbl or {}, isArray)
end

function OBJDEF:newObject(tbl)
	return setmetatable(tbl or {}, isObject)
end

local function getnum(op)
	return type(op) == "number" and op or op.N
end

local isNumber = {
	__tostring = function(T)
		return T.S
	end,
	__unm = function(op)
		return getnum(op)
	end,

	__concat = function(op1, op2)
		return tostring(op1) .. tostring(op2)
	end,
	__add = function(op1, op2)
		return getnum(op1) + getnum(op2)
	end,
	__sub = function(op1, op2)
		return getnum(op1) - getnum(op2)
	end,
	__mul = function(op1, op2)
		return getnum(op1) * getnum(op2)
	end,
	__div = function(op1, op2)
		return getnum(op1) / getnum(op2)
	end,
	__mod = function(op1, op2)
		return getnum(op1) % getnum(op2)
	end,
	__pow = function(op1, op2)
		return getnum(op1) ^ getnum(op2)
	end,
	__lt = function(op1, op2)
		return getnum(op1) < getnum(op2)
	end,
	__eq = function(op1, op2)
		return getnum(op1) == getnum(op2)
	end,
	__le = function(op1, op2)
		return getnum(op1) <= getnum(op2)
	end,
}
isNumber.__index = isNumber

function OBJDEF:asNumber(item)
	if getmetatable(item) == isNumber then
		-- it's already a JSON number object.
		return item
	elseif type(item) == "table" and type(item.S) == "string" and type(item.N) == "number" then
		-- it's a number-object table that lost its metatable, so give it one
		return setmetatable(item, isNumber)
	else
		-- the normal situation... given a number or a string representation of a number....
		local holder = {
			S = tostring(item), -- S is the representation of the number as a string, which remains precise
			N = tonumber(item), -- N is the number as a Lua number.
		}
		return setmetatable(holder, isNumber)
	end
end

function OBJDEF:forceString(item)
	if type(item) == "table" and type(item.S) == "string" then
		return item.S
	else
		return tostring(item)
	end
end

function OBJDEF:forceNumber(item)
	if type(item) == "table" and type(item.N) == "number" then
		return item.N
	else
		return tonumber(item)
	end
end

local function unicode_codepoint_as_utf8(codepoint)
	--
	-- codepoint is a number
	--
	if codepoint <= 127 then
		return string.char(codepoint)
	elseif codepoint <= 2047 then
		--
		-- 110yyyxx 10xxxxxx         <-- useful notation from http://en.wikipedia.org/wiki/Utf8
		--
		local highpart = math.floor(codepoint / 0x40)
		local lowpart = codepoint - (0x40 * highpart)
		return string.char(0xC0 + highpart, 0x80 + lowpart)
	elseif codepoint <= 65535 then
		--
		-- 1110yyyy 10yyyyxx 10xxxxxx
		--
		local highpart = math.floor(codepoint / 0x1000)
		local remainder = codepoint - 0x1000 * highpart
		local midpart = math.floor(remainder / 0x40)
		local lowpart = remainder - 0x40 * midpart

		highpart = 0xE0 + highpart
		midpart = 0x80 + midpart
		lowpart = 0x80 + lowpart

		--
		-- Check for an invalid character (thanks Andy R. at Adobe).
		-- See table 3.7, page 93, in http://www.unicode.org/versions/Unicode5.2.0/ch03.pdf#G28070
		--
		if
			(highpart == 0xE0 and midpart < 0xA0)
			or (highpart == 0xED and midpart > 0x9F)
			or (highpart == 0xF0 and midpart < 0x90)
			or (highpart == 0xF4 and midpart > 0x8F)
		then
			return "?"
		else
			return string.char(highpart, midpart, lowpart)
		end
	else
		--
		-- 11110zzz 10zzyyyy 10yyyyxx 10xxxxxx
		--
		local highpart = math.floor(codepoint / 0x40000)
		local remainder = codepoint - 0x40000 * highpart
		local midA = math.floor(remainder / 0x1000)
		remainder = remainder - 0x1000 * midA
		local midB = math.floor(remainder / 0x40)
		local lowpart = remainder - 0x40 * midB

		return string.char(0xF0 + highpart, 0x80 + midA, 0x80 + midB, 0x80 + lowpart)
	end
end

function OBJDEF:onDecodeError(message, text, location, etc)
	if text then
		if location then
			message = string.format("%s at byte %d of: %s", message, location, text)
		else
			message = string.format("%s: %s", message, text)
		end
	end

	if etc ~= nil then
		message = message .. " (" .. OBJDEF:encode(etc) .. ")"
	end

	if self.assert then
		self.assert(false, message)
	else
		assert(false, message)
	end
end

function OBJDEF:onTrailingGarbage(json_text, location, parsed_value, etc)
	return self:onDecodeError("trailing garbage", json_text, location, etc)
end

OBJDEF.onDecodeOfNilError = OBJDEF.onDecodeError
OBJDEF.onDecodeOfHTMLError = OBJDEF.onDecodeError

function OBJDEF:onEncodeError(message, etc)
	if etc ~= nil then
		message = message .. " (" .. OBJDEF:encode(etc) .. ")"
	end

	if self.assert then
		self.assert(false, message)
	else
		assert(false, message)
	end
end

local function grok_number(self, text, start, options)
	--
	-- Grab the integer part
	--
	local integer_part = text:match("^-?[1-9]%d*", start) or text:match("^-?0", start)

	if not integer_part then
		self:onDecodeError("expected number", text, start, options.etc)
		return nil, start -- in case the error method doesn't abort, return something sensible
	end

	local i = start + integer_part:len()

	--
	-- Grab an optional decimal part
	--
	local decimal_part = text:match("^%.%d+", i) or ""

	i = i + decimal_part:len()

	--
	-- Grab an optional exponential part
	--
	local exponent_part = text:match("^[eE][-+]?%d+", i) or ""

	i = i + exponent_part:len()

	local full_number_text = integer_part .. decimal_part .. exponent_part

	if options.decodeNumbersAsObjects then
		return OBJDEF:asNumber(full_number_text), i
	end

	--
	-- If we're told to stringify under certain conditions, so do.
	-- We punt a bit when there's an exponent by just stringifying no matter what.
	-- I suppose we should really look to see whether the exponent is actually big enough one
	-- way or the other to trip stringification, but I'll be lazy about it until someone asks.
	--
	if
		(
			options.decodeIntegerStringificationLength
			and (integer_part:len() >= options.decodeIntegerStringificationLength or exponent_part:len() > 0)
		)
		or (
			options.decodeDecimalStringificationLength
			and (decimal_part:len() >= options.decodeDecimalStringificationLength or exponent_part:len() > 0)
		)
	then
		return full_number_text, i -- this returns the exact string representation seen in the original JSON
	end

	local as_number = tonumber(full_number_text)

	if not as_number then
		self:onDecodeError("bad number", text, start, options.etc)
		return nil, start -- in case the error method doesn't abort, return something sensible
	end

	return as_number, i
end

local function grok_string(self, text, start, options)
	if text:sub(start, start) ~= '"' then
		self:onDecodeError("expected string's opening quote", text, start, options.etc)
		return nil, start -- in case the error method doesn't abort, return something sensible
	end

	local i = start + 1 -- +1 to bypass the initial quote
	local text_len = text:len()
	local VALUE = ""
	while i <= text_len do
		local c = text:sub(i, i)
		if c == '"' then
			return VALUE, i + 1
		end
		if c ~= "\\" then
			VALUE = VALUE .. c
			i = i + 1
		elseif text:match("^\\b", i) then
			VALUE = VALUE .. "\b"
			i = i + 2
		elseif text:match("^\\f", i) then
			VALUE = VALUE .. "\f"
			i = i + 2
		elseif text:match("^\\n", i) then
			VALUE = VALUE .. "\n"
			i = i + 2
		elseif text:match("^\\r", i) then
			VALUE = VALUE .. "\r"
			i = i + 2
		elseif text:match("^\\t", i) then
			VALUE = VALUE .. "\t"
			i = i + 2
		else
			local hex = text:match(
				"^\\u([0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF])",
				i
			)
			if hex then
				i = i + 6 -- bypass what we just read

				-- We have a Unicode codepoint. It could be standalone, or if in the proper range and
				-- followed by another in a specific range, it'll be a two-code surrogate pair.
				local codepoint = tonumber(hex, 16)
				if codepoint >= 0xD800 and codepoint <= 0xDBFF then
					-- it's a hi surrogate... see whether we have a following low
					local lo_surrogate =
						text:match("^\\u([dD][cdefCDEF][0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF])", i)
					if lo_surrogate then
						i = i + 6 -- bypass the low surrogate we just read
						codepoint = 0x2400 + (codepoint - 0xD800) * 0x400 + tonumber(lo_surrogate, 16)
					else
						-- not a proper low, so we'll just leave the first codepoint as is and spit it out.
					end
				end
				VALUE = VALUE .. unicode_codepoint_as_utf8(codepoint)
			else
				-- just pass through what's escaped
				VALUE = VALUE .. text:match("^\\(.)", i)
				i = i + 2
			end
		end
	end

	self:onDecodeError("unclosed string", text, start, options.etc)
	return nil, start -- in case the error method doesn't abort, return something sensible
end

local function skip_whitespace(text, start)
	local _, match_end = text:find("^[ \n\r\t]+", start) -- [http://www.ietf.org/rfc/rfc4627.txt] Section 2
	if match_end then
		return match_end + 1
	else
		return start
	end
end

-- Count newlines in `text` up to `start`
local function count_newlines(text, start)
	local _, count = text:sub(1, start):gsub("\n", "\n")

	return count
end

-- Count characters from `i` to previous newline
-- {hello:sa\nmple\n    test}
local function get_relative_i(text, i)
	-- Find next newline from `i` backwards

	local count = 0

	for j = i, 1, -1 do
		if text:sub(j, j) == "\n" then
			break
		end
		count = count + 1
	end

	return count
end

local grok_one -- assigned later

local function grok_object(self, text, start, options)
	if text:sub(start, start) ~= "{" then
		self:onDecodeError("expected '{'", text, start, options.etc)
		return nil, start -- in case the error method doesn't abort, return something sensible
	end

	local i = skip_whitespace(text, start + 1) -- +1 to skip the '{'

	local VALUE = self.strictTypes and self:newObject({}) or {}

	if text:sub(i, i) == "}" then
		return VALUE, i + 1
	end
	local text_len = text:len()
	while i <= text_len do
		local key, new_i = grok_string(self, text, i, options)

		---- Find start of JSON key
		local key_start = i
		local newlines = count_newlines(text, key_start)
		local relative_start = get_relative_i(text, key_start)

		i = skip_whitespace(text, new_i)

		if text:sub(i, i) ~= ":" then
			self:onDecodeError("expected colon", text, i, options.etc)
			return nil, i -- in case the error method doesn't abort, return something sensible
		end

		i = skip_whitespace(text, i + 1)

		local new_val, new_i = grok_one(self, text, i, options)

		---- Add start position so we can quickly jump to it
		VALUE[key] = {
			value = new_val,
			line_number = (newlines or 0) + 1,
			key_start = relative_start + 1,
			value_start = get_relative_i(text, i),
		}

		--
		-- Expect now either '}' to end things, or a ',' to allow us to continue.
		--
		i = skip_whitespace(text, new_i)

		local c = text:sub(i, i)

		if c == "}" then
			return VALUE, i + 1
		end

		if text:sub(i, i) ~= "," then
			self:onDecodeError("expected comma or '}'", text, i, options.etc)
			return nil, i -- in case the error method doesn't abort, return something sensible
		end

		i = skip_whitespace(text, i + 1)
	end

	self:onDecodeError("unclosed '{'", text, start, options.etc)
	return nil, start -- in case the error method doesn't abort, return something sensible
end

local function grok_array(self, text, start, options)
	if text:sub(start, start) ~= "[" then
		self:onDecodeError("expected '['", text, start, options.etc)
		return nil, start -- in case the error method doesn't abort, return something sensible
	end

	local i = skip_whitespace(text, start + 1) -- +1 to skip the '['
	local VALUE = self.strictTypes and self:newArray({}) or {}
	if text:sub(i, i) == "]" then
		return VALUE, i + 1
	end

	local VALUE_INDEX = 1

	local text_len = text:len()
	while i <= text_len do
		local val, new_i = grok_one(self, text, i, options)
		local newlines = count_newlines(text, i)
		local relative_start = get_relative_i(text, i)

		i = skip_whitespace(text, new_i)

		-- can't table.insert(VALUE, val) here because it's a no-op if val is nil
		VALUE[VALUE_INDEX] = {
			value = val,
			line_number = (newlines or 0) + 1,
			value_start = relative_start,
			key_start = relative_start,
		}
		VALUE_INDEX = VALUE_INDEX + 1

		--
		-- Expect now either ']' to end things, or a ',' to allow us to continue.
		--
		local c = text:sub(i, i)
		if c == "]" then
			return VALUE, i + 1
		end
		if text:sub(i, i) ~= "," then
			self:onDecodeError("expected comma or ']'", text, i, options.etc)
			return nil, i -- in case the error method doesn't abort, return something sensible
		end
		i = skip_whitespace(text, i + 1)
	end
	self:onDecodeError("unclosed '['", text, start, options.etc)
	return nil, i -- in case the error method doesn't abort, return something sensible
end

grok_one = function(self, text, start, options)
	-- Skip any whitespace
	start = skip_whitespace(text, start)

	if start > text:len() then
		self:onDecodeError("unexpected end of string", text, nil, options.etc)
		return nil, start -- in case the error method doesn't abort, return something sensible
	end

	if text:find('^"', start) then
		return grok_string(self, text, start, options.etc)
	elseif text:find("^[-0123456789 ]", start) then
		return grok_number(self, text, start, options)
	elseif text:find("^%{", start) then
		return grok_object(self, text, start, options)
	elseif text:find("^%[", start) then
		return grok_array(self, text, start, options)
	elseif text:find("^true", start) then
		return true, start + 4
	elseif text:find("^false", start) then
		return false, start + 5
	elseif text:find("^null", start) then
		return nil, start + 4
	else
		self:onDecodeError("can't parse JSON", text, start, options.etc)
		return nil, 1 -- in case the error method doesn't abort, return something sensible
	end
end

function OBJDEF:decode(text, etc, options)
	--
	-- If the user didn't pass in a table of decode options, make an empty one.
	--
	if type(options) ~= "table" then
		options = {}
	end

	--
	-- If they passed in an 'etc' argument, stuff it into the options.
	-- (If not, any 'etc' field in the options they passed in remains to be used)
	--
	if etc ~= nil then
		options.etc = etc
	end

	if text:match("^%s*$") then
		-- an empty string is nothing, but not an error
		return nil
	end

	if text:match("^%s*<") then
		-- Can't be JSON... we'll assume it's HTML
		local error_message = "HTML passed to JSON:decode()"
		self:onDecodeOfHTMLError(error_message, text, nil, options.etc)
		return nil, error_message -- in case the error method doesn't abort, return something sensible
	end

	--
	-- Ensure that it's not UTF-32 or UTF-16.
	-- Those are perfectly valid encodings for JSON (as per RFC 4627 section 3),
	-- but this package can't handle them.
	--
	if text:sub(1, 1):byte() == 0 or (text:len() >= 2 and text:sub(2, 2):byte() == 0) then
		local error_message = "JSON package groks only UTF-8, sorry"
		self:onDecodeError(error_message, text, nil, options.etc)
		return nil, error_message -- in case the error method doesn't abort, return something sensible
	end

	--
	-- apply global options
	--
	if options.decodeNumbersAsObjects == nil then
		options.decodeNumbersAsObjects = self.decodeNumbersAsObjects
	end
	if options.decodeIntegerStringificationLength == nil then
		options.decodeIntegerStringificationLength = self.decodeIntegerStringificationLength
	end
	if options.decodeDecimalStringificationLength == nil then
		options.decodeDecimalStringificationLength = self.decodeDecimalStringificationLength
	end

	--
	-- Finally, go parse it
	--
	local success, value, next_i = pcall(grok_one, self, text, 1, options)

	if success then
		local error_message = nil
		if next_i ~= #text + 1 then
			-- something's left over after we parsed the first thing.... whitespace is allowed.
			next_i = skip_whitespace(text, next_i)

			-- if we have something left over now, it's trailing garbage
			if next_i ~= #text + 1 then
				value, error_message = self:onTrailingGarbage(text, next_i, value, options.etc)
			end
		end
		return value, error_message
	else
		-- If JSON:onDecodeError() didn't abort out of the pcall, we'll have received
		-- the error message here as "value", so pass it along as an assert.
		local error_message = value
		if self.assert then
			self.assert(false, error_message)
		else
			assert(false, error_message)
		end
		-- ...and if we're still here (because the assert didn't throw an error),
		-- return a nil and throw the error message on as a second arg
		return nil, error_message
	end
end

function OBJDEF.__tostring()
	return "JSON encode/decode package"
end

OBJDEF.__index = OBJDEF

function OBJDEF:new(args)
	local new = {}

	if args then
		for key, val in pairs(args) do
			new[key] = val
		end
	end

	return setmetatable(new, OBJDEF)
end

return OBJDEF:new()