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|
---------------------------------------------------
-- Utility module.
-- @class module
-- @name luacov.util
local util = {}
--- Removes a prefix from a string if it's present.
-- @param str a string.
-- @param prefix a prefix string.
-- @return original string if does not start with prefix
-- or string without prefix.
function util.unprefix(str, prefix)
if str:sub(1, #prefix) == prefix then
return str:sub(#prefix + 1)
else
return str
end
end
-- Returns contents of a file or nil + error message.
local function read_file(name)
local f, open_err = io.open(name, "rb")
if not f then
return nil, util.unprefix(open_err, name .. ": ")
end
local contents, read_err = f:read("*a")
f:close()
if contents then
return contents
else
return nil, read_err
end
end
--- Loads a string.
-- @param str a string.
-- @param[opt] env environment table.
-- @param[opt] chunkname chunk name.
function util.load_string(str, env, chunkname)
if _VERSION:find("5%.1") then
local func, err = loadstring(str, chunkname) -- luacheck: compat
if not func then
return nil, err
end
if env then
setfenv(func, env) -- luacheck: compat
end
return func
else
return load(str, chunkname, "bt", env or _ENV) -- luacheck: compat
end
end
--- Load a config file.
-- Reads, loads and runs a Lua file in an environment.
-- @param name file name.
-- @param env environment table.
-- @return true and the first return value of config on success,
-- nil + error type + error message on failure, where error type
-- can be "read", "load" or "run".
function util.load_config(name, env)
local src, read_err = read_file(name)
if not src then
return nil, "read", read_err
end
local func, load_err = util.load_string(src, env, "@config")
if not func then
return nil, "load", "line " .. util.unprefix(load_err, "config:")
end
local ok, ret = pcall(func)
if not ok then
return nil, "run", "line " .. util.unprefix(ret, "config:")
end
return true, ret
end
--- Checks if a file exists.
-- @param name file name.
-- @return true if file can be opened, false otherwise.
function util.file_exists(name)
local f = io.open(name)
if f then
f:close()
return true
else
return false
end
end
return util
|
