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224 lines
4.9 KiB
Go
224 lines
4.9 KiB
Go
package godotenv
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import (
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"bytes"
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"errors"
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"fmt"
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"strings"
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"unicode"
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)
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const (
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charComment = '#'
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prefixSingleQuote = '\''
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prefixDoubleQuote = '"'
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exportPrefix = "export"
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)
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func parseBytes(src []byte, out map[string]string, lookupFn LookupFn) error {
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cutset := src
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for {
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cutset = getStatementStart(cutset)
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if cutset == nil {
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// reached end of file
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break
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}
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key, left, inherited, err := locateKeyName(cutset)
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if err != nil {
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return err
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}
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if strings.Contains(key, " ") {
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return errors.New("key cannot contain a space")
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}
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if inherited {
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if lookupFn == nil {
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lookupFn = noLookupFn
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}
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value, ok := lookupFn(key)
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if ok {
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out[key] = value
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cutset = left
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continue
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}
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}
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value, left, err := extractVarValue(left, out, lookupFn)
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if err != nil {
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return err
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}
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out[key] = value
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cutset = left
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}
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return nil
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}
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// getStatementPosition returns position of statement begin.
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//
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// It skips any comment line or non-whitespace character.
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func getStatementStart(src []byte) []byte {
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pos := indexOfNonSpaceChar(src)
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if pos == -1 {
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return nil
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}
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src = src[pos:]
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if src[0] != charComment {
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return src
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}
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// skip comment section
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pos = bytes.IndexFunc(src, isCharFunc('\n'))
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if pos == -1 {
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return nil
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}
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return getStatementStart(src[pos:])
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}
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// locateKeyName locates and parses key name and returns rest of slice
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func locateKeyName(src []byte) (key string, cutset []byte, inherited bool, err error) {
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// trim "export" and space at beginning
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src = bytes.TrimLeftFunc(bytes.TrimPrefix(src, []byte(exportPrefix)), isSpace)
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// locate key name end and validate it in single loop
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offset := 0
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loop:
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for i, char := range src {
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rchar := rune(char)
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if isSpace(rchar) {
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continue
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}
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switch char {
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case '=', ':', '\n':
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// library also supports yaml-style value declaration
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key = string(src[0:i])
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offset = i + 1
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inherited = char == '\n'
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break loop
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case '_':
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default:
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// variable name should match [A-Za-z0-9_]
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if unicode.IsLetter(rchar) || unicode.IsNumber(rchar) {
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continue
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}
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return "", nil, inherited, fmt.Errorf(
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`unexpected character %q in variable name near %q`,
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string(char), string(src))
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}
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}
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if len(src) == 0 {
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return "", nil, inherited, errors.New("zero length string")
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}
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// trim whitespace
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key = strings.TrimRightFunc(key, unicode.IsSpace)
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cutset = bytes.TrimLeftFunc(src[offset:], isSpace)
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return key, cutset, inherited, nil
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}
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// extractVarValue extracts variable value and returns rest of slice
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func extractVarValue(src []byte, envMap map[string]string, lookupFn LookupFn) (value string, rest []byte, err error) {
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quote, hasPrefix := hasQuotePrefix(src)
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if !hasPrefix {
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// unquoted value - read until whitespace
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end := bytes.IndexFunc(src, unicode.IsSpace)
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if end == -1 {
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return expandVariables(string(src), envMap, lookupFn), nil, nil
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}
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return expandVariables(string(src[0:end]), envMap, lookupFn), src[end:], nil
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}
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// lookup quoted string terminator
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for i := 1; i < len(src); i++ {
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if char := src[i]; char != quote {
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continue
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}
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// skip escaped quote symbol (\" or \', depends on quote)
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if prevChar := src[i-1]; prevChar == '\\' {
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continue
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}
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// trim quotes
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trimFunc := isCharFunc(rune(quote))
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value = string(bytes.TrimLeftFunc(bytes.TrimRightFunc(src[0:i], trimFunc), trimFunc))
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if quote == prefixDoubleQuote {
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// unescape newlines for double quote (this is compat feature)
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// and expand environment variables
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value = expandVariables(expandEscapes(value), envMap, lookupFn)
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}
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return value, src[i+1:], nil
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}
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// return formatted error if quoted string is not terminated
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valEndIndex := bytes.IndexFunc(src, isCharFunc('\n'))
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if valEndIndex == -1 {
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valEndIndex = len(src)
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}
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return "", nil, fmt.Errorf("unterminated quoted value %s", src[:valEndIndex])
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}
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func expandEscapes(str string) string {
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out := escapeRegex.ReplaceAllStringFunc(str, func(match string) string {
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c := strings.TrimPrefix(match, `\`)
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switch c {
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case "n":
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return "\n"
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case "r":
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return "\r"
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default:
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return match
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}
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})
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return unescapeCharsRegex.ReplaceAllString(out, "$1")
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}
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func indexOfNonSpaceChar(src []byte) int {
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return bytes.IndexFunc(src, func(r rune) bool {
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return !unicode.IsSpace(r)
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})
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}
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// hasQuotePrefix reports whether charset starts with single or double quote and returns quote character
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func hasQuotePrefix(src []byte) (prefix byte, isQuored bool) {
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if len(src) == 0 {
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return 0, false
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}
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switch prefix := src[0]; prefix {
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case prefixDoubleQuote, prefixSingleQuote:
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return prefix, true
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default:
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return 0, false
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}
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}
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func isCharFunc(char rune) func(rune) bool {
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return func(v rune) bool {
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return v == char
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}
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}
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// isSpace reports whether the rune is a space character but not line break character
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//
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// this differs from unicode.IsSpace, which also applies line break as space
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func isSpace(r rune) bool {
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switch r {
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case '\t', '\v', '\f', '\r', ' ', 0x85, 0xA0:
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return true
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}
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return false
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}
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