util/jsonpointer.lua
author Kim Alvefur <zash@zash.se>
Mon, 07 Mar 2022 00:35:29 +0100
changeset 12392 50fcd3879482
parent 12135 b4c0efff8dd3
child 12500 87c3d45208ef
permissions -rw-r--r--
spelling: non-existing mistakes (thanks timeless)
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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local function unescape_token(escaped_token)
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	local unescaped = escaped_token:gsub("~1", "/"):gsub("~0", "~")
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	return unescaped
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end
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local function resolve_json_pointer(ref, path)
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	local ptr_len = #path + 1
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	for part, pos in path:gmatch("/([^/]*)()") do
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		local token = unescape_token(part)
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		if not (type(ref) == "table") then
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			return nil
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		end
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		local idx = next(ref)
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		local new_ref
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		if type(idx) == "string" then
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			new_ref = ref[token]
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		elseif math.type(idx) == "integer" then
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			local i = tonumber(token)
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			if token == "-" then
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				i = #ref + 1
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			end
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			new_ref = ref[i]
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		else
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			return nil, "invalid-table"
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		end
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		if pos == ptr_len then
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			return new_ref
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		elseif type(new_ref) == "table" then
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			ref = new_ref
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		elseif not (type(ref) == "table") then
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			return nil, "invalid-path"
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		end
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	end
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	return ref
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end
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return { resolve = resolve_json_pointer }