Sebastiaan van Stijn
76196dbb01
- the function already trimmed leading whitespace from each line before parsing. keys with trailing whitespace would be invalidated, and values have whitespace preserved, so there's no need to trim whitespace for the key. - if a line is validated (key is valid), we don't need to reconstruct the key=value by concatenating, and we can add the line as-is. - check if the key is empty before checking if it contains whitespace - touch-up comments - rename some variables for readability - slight cleanup to use early returns / early continues to reduce nesting Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
71 lines
1.9 KiB
Go
71 lines
1.9 KiB
Go
package opts
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import (
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"bufio"
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"bytes"
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"fmt"
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"os"
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"strings"
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"unicode"
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"unicode/utf8"
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)
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const whiteSpaces = " \t"
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func parseKeyValueFile(filename string, lookupFn func(string) (string, bool)) ([]string, error) {
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fh, err := os.Open(filename)
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if err != nil {
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return []string{}, err
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}
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defer fh.Close()
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lines := []string{}
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scanner := bufio.NewScanner(fh)
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utf8bom := []byte{0xEF, 0xBB, 0xBF}
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for currentLine := 1; scanner.Scan(); currentLine++ {
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scannedBytes := scanner.Bytes()
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if !utf8.Valid(scannedBytes) {
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return []string{}, fmt.Errorf("env file %s contains invalid utf8 bytes at line %d: %v", filename, currentLine, scannedBytes)
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}
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// We trim UTF8 BOM
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if currentLine == 1 {
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scannedBytes = bytes.TrimPrefix(scannedBytes, utf8bom)
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}
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// trim the line from all leading whitespace first. trailing whitespace
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// is part of the value, and is kept unmodified.
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line := strings.TrimLeftFunc(string(scannedBytes), unicode.IsSpace)
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if len(line) == 0 || line[0] == '#' {
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// skip empty lines and comments (lines starting with '#')
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continue
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}
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key, _, hasValue := strings.Cut(line, "=")
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if len(key) == 0 {
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return []string{}, fmt.Errorf("no variable name on line '%s'", line)
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}
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// leading whitespace was already removed from the line, but
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// variables are not allowed to contain whitespace or have
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// trailing whitespace.
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if strings.ContainsAny(key, whiteSpaces) {
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return []string{}, fmt.Errorf("variable '%s' contains whitespaces", key)
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}
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if hasValue {
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// key/value pair is valid and has a value; add the line as-is.
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lines = append(lines, line)
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continue
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}
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if lookupFn != nil {
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// No value given; try to look up the value. The value may be
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// empty but if no value is found, the key is omitted.
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if value, found := lookupFn(line); found {
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lines = append(lines, key+"="+value)
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}
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}
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}
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return lines, scanner.Err()
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}
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