75 lines
2.0 KiB
Lua
75 lines
2.0 KiB
Lua
---------
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-- Utility functions for operations on a file system.
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--
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-- **Note: This module is not part of public API!**
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----
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local fmt = string.format
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local open = io.open
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local UTF8_BOM = '\239\187\191'
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local function normalize_io_error (name, err)
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if err:sub(1, #name + 2) == name..': ' then
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err = err:sub(#name + 3)
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end
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return err
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end
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local M = {}
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--- Reads the specified file and returns its content as string.
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--
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-- @tparam string filename Path of the file to read.
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-- @tparam string mode The mode in which to open the file, see @{io.open} (default: "r").
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-- @treturn[1] string A content of the file.
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-- @treturn[2] nil
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-- @treturn[2] string An error message.
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function M.read_file (filename, mode)
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local handler, err = open(filename, mode or 'r')
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if not handler then
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return nil, fmt('Could not open %s for reading: %s',
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filename, normalize_io_error(filename, err))
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end
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local content, err = handler:read('*a') --luacheck: ignore 411
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if not content then
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return nil, fmt('Could not read %s: %s', filename, normalize_io_error(filename, err))
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end
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handler:close()
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if content:sub(1, #UTF8_BOM) == UTF8_BOM then
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content = content:sub(#UTF8_BOM + 1)
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end
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return content
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end
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--- Writes the given data to the specified file.
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--
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-- @tparam string filename Path of the file to write.
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-- @tparam string data The data to write.
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-- @tparam ?string mode The mode in which to open the file, see @{io.open} (default: "w").
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-- @treturn[1] true
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-- @treturn[2] nil
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-- @treturn[2] string An error message.
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function M.write_file (filename, data, mode)
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local handler, err = open(filename, mode or 'w')
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if not handler then
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return nil, fmt('Could not open %s for writing: %s',
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filename, normalize_io_error(filename, err))
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end
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local _, err = handler:write(data) --luacheck: ignore 411
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if err then
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return nil, fmt('Could not write %s: %s', filename, normalize_io_error(filename, err))
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end
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handler:flush()
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handler:close()
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return true
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end
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return M
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