mirror of
https://github.com/appgurueu/modlib.git
synced 2024-08-19 21:04:13 +02:00
194 lines
4.6 KiB
Lua
194 lines
4.6 KiB
Lua
-- Localize globals
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local assert, error, io, loadfile, math, minetest, modlib, pairs, setfenv, setmetatable, type
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= assert, error, io, loadfile, math, minetest, modlib, pairs, setfenv, setmetatable, type
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-- Set environment
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local _ENV = {}
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setfenv(1, _ENV)
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-- Default value
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reference_strings = true
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-- Note: keys may not be marked as weak references: garbage collected log files wouldn't close the file:
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-- The `__gc` metamethod doesn't work for tables in Lua 5.1; a hack using `newproxy` would be needed
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-- See https://stackoverflow.com/questions/27426704/lua-5-1-workaround-for-gc-metamethod-for-tables)
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-- Therefore, :close() must be called on log files to remove them from the `files` table
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local files = {}
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local metatable = {__index = _ENV}
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_ENV.metatable = metatable
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function new(file_path, root, reference_strings)
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local self = setmetatable({
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file_path = assert(file_path),
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root = root,
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reference_strings = reference_strings
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}, metatable)
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if minetest then
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files[self] = true
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end
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return self
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end
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local function set_references(self, table)
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-- Weak table keys to allow the collection of dead reference tables
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-- TODO garbage collect strings in the references table
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self.references = setmetatable(table, {__mode = "k"})
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end
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function load(self)
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-- Bytecode is blocked by the engine
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local read = assert(loadfile(self.file_path))
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-- math.huge is serialized to inf
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local env = {inf = math.huge}
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setfenv(read, env)
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read()
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env.R = env.R or {{}}
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local reference_count = #env.R
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for ref in pairs(env.R) do
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if ref > reference_count then
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-- Ensure reference count always has the value of the largest reference
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-- in case of "holes" (nil values) in the reference list
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reference_count = ref
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end
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end
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self.reference_count = reference_count
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self.root = env.R[1]
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set_references(self, {})
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end
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function open(self)
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self.file = io.open(self.file_path, "a+")
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end
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function init(self)
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if modlib.file.exists(self.file_path) then
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self:load()
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self:_rewrite()
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self:open()
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return
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end
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self:open()
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self:_write()
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end
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function log(self, statement)
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self.file:write(statement)
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self.file:write"\n"
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end
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function flush(self)
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self.file:flush()
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end
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function close(self)
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self.file:close()
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self.file = nil
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files[self] = nil
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end
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if minetest then
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minetest.register_on_shutdown(function()
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for self in pairs(files) do
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self.file:close()
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end
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end)
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end
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local function _dump(self, value, is_key)
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if value == nil then
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return "nil"
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end
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if value == true then
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return "true"
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end
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if value == false then
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return "false"
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end
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if value ~= value then
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-- nan
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return "0/0"
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end
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local _type = type(value)
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if _type == "number" then
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return ("%.17g"):format(value)
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end
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local reference = self.references[value]
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if reference then
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return "R[" .. reference .."]"
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end
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reference = self.reference_count + 1
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local key = "R[" .. reference .."]"
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local function create_reference()
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self.reference_count = reference
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self.references[value] = reference
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end
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if _type == "string" then
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local reference_strings = self.reference_strings
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if is_key and ((not reference_strings) or value:len() <= key:len()) and modlib.text.is_identifier(value) then
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-- Short key
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return value, true
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end
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local formatted = ("%q"):format(value)
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if (not reference_strings) or formatted:len() <= key:len() then
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-- Short string
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return formatted
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end
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-- Use reference
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create_reference()
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self:log(key .. "=" .. formatted)
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elseif _type == "table" then
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-- Tables always need a reference before they are traversed to prevent infinite recursion
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create_reference()
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-- TODO traverse tables to determine whether this is actually needed
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self:log(key .. "={}")
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for k, v in pairs(value) do
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local dumped, short = _dump(self, k, true)
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self:log(key .. (short and ("." .. dumped) or ("[" .. dumped .. "]")) .. "=" .. _dump(self, v))
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end
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else
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error("unsupported type: " .. _type)
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end
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return key
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end
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function set(self, table, key, value)
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if not self.references[table] then
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error"orphan table"
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end
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if table[key] == value then
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-- No change
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return
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end
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table[key] = value
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table = _dump(self, table)
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local key, short_key = _dump(self, key, true)
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self:log(table .. (short_key and ("." .. key) or ("[" .. key .. "]")) .. "=" .. _dump(self, value))
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end
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function set_root(self, key, value)
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return self:set(self.root, key, value)
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end
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function _write(self)
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set_references(self, {})
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self.reference_count = 0
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self:log"R={}"
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_dump(self, self.root)
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end
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function _rewrite(self)
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self.file = io.open(self.file_path, "w+")
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self:_write()
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self.file:close()
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end
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function rewrite(self)
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if self.file then
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self.file:close()
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end
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self:_rewrite()
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self:open()
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end
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-- Export environment
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return _ENV |