File

util/jsonpointer.lua @ 13135:3fd24e1945b0

mod_storage_internal: Lazy-load archive items while iterating Very large list files previously ran into limits of the Lua parser, or just caused Prosody to freeze while parsing. Using the new index we can parse individual items one at a time. This probably won't reduce overall CPU usage, probably the opposite, but it will reduce the number of items in memory at once and allow collection of items after we iterated past them.
author Kim Alvefur <zash@zash.se>
date Wed, 12 May 2021 01:25:44 +0200
parent 12781:22066b02887f
line wrap: on
line source

local m_type = math.type;

local function unescape_token(escaped_token)
	local unescaped = escaped_token:gsub("~1", "/"):gsub("~0", "~")
	return unescaped
end

local function resolve_json_pointer(ref, path)
	local ptr_len = #path + 1
	for part, pos in path:gmatch("/([^/]*)()") do
		local token = unescape_token(part)
		if not (type(ref) == "table") then
			return nil
		end
		local idx = next(ref)
		local new_ref

		if type(idx) == "string" then
			new_ref = ref[token]
		elseif m_type(idx) == "integer" then
			local i = tonumber(token)
			if token == "-" then
				i = #ref + 1
			end
			new_ref = ref[i + 1]
		else
			return nil, "invalid-table"
		end

		if pos == ptr_len then
			return new_ref
		elseif type(new_ref) == "table" then
			ref = new_ref
		elseif not (type(ref) == "table") then
			return nil, "invalid-path"
		end

	end
	return ref
end

return { resolve = resolve_json_pointer }