+++ /dev/null
-package logfmt
-
-import (
- "bufio"
- "bytes"
- "fmt"
- "io"
- "unicode/utf8"
-)
-
-// A Decoder reads and decodes logfmt records from an input stream.
-type Decoder struct {
- pos int
- key []byte
- value []byte
- lineNum int
- s *bufio.Scanner
- err error
-}
-
-// NewDecoder returns a new decoder that reads from r.
-//
-// The decoder introduces its own buffering and may read data from r beyond
-// the logfmt records requested.
-func NewDecoder(r io.Reader) *Decoder {
- dec := &Decoder{
- s: bufio.NewScanner(r),
- }
- return dec
-}
-
-// ScanRecord advances the Decoder to the next record, which can then be
-// parsed with the ScanKeyval method. It returns false when decoding stops,
-// either by reaching the end of the input or an error. After ScanRecord
-// returns false, the Err method will return any error that occurred during
-// decoding, except that if it was io.EOF, Err will return nil.
-func (dec *Decoder) ScanRecord() bool {
- if dec.err != nil {
- return false
- }
- if !dec.s.Scan() {
- dec.err = dec.s.Err()
- return false
- }
- dec.lineNum++
- dec.pos = 0
- return true
-}
-
-// ScanKeyval advances the Decoder to the next key/value pair of the current
-// record, which can then be retrieved with the Key and Value methods. It
-// returns false when decoding stops, either by reaching the end of the
-// current record or an error.
-func (dec *Decoder) ScanKeyval() bool {
- dec.key, dec.value = nil, nil
- if dec.err != nil {
- return false
- }
-
- line := dec.s.Bytes()
-
- // garbage
- for p, c := range line[dec.pos:] {
- if c > ' ' {
- dec.pos += p
- goto key
- }
- }
- dec.pos = len(line)
- return false
-
-key:
- const invalidKeyError = "invalid key"
-
- start, multibyte := dec.pos, false
- for p, c := range line[dec.pos:] {
- switch {
- case c == '=':
- dec.pos += p
- if dec.pos > start {
- dec.key = line[start:dec.pos]
- if multibyte && bytes.IndexRune(dec.key, utf8.RuneError) != -1 {
- dec.syntaxError(invalidKeyError)
- return false
- }
- }
- if dec.key == nil {
- dec.unexpectedByte(c)
- return false
- }
- goto equal
- case c == '"':
- dec.pos += p
- dec.unexpectedByte(c)
- return false
- case c <= ' ':
- dec.pos += p
- if dec.pos > start {
- dec.key = line[start:dec.pos]
- if multibyte && bytes.IndexRune(dec.key, utf8.RuneError) != -1 {
- dec.syntaxError(invalidKeyError)
- return false
- }
- }
- return true
- case c >= utf8.RuneSelf:
- multibyte = true
- }
- }
- dec.pos = len(line)
- if dec.pos > start {
- dec.key = line[start:dec.pos]
- if multibyte && bytes.IndexRune(dec.key, utf8.RuneError) != -1 {
- dec.syntaxError(invalidKeyError)
- return false
- }
- }
- return true
-
-equal:
- dec.pos++
- if dec.pos >= len(line) {
- return true
- }
- switch c := line[dec.pos]; {
- case c <= ' ':
- return true
- case c == '"':
- goto qvalue
- }
-
- // value
- start = dec.pos
- for p, c := range line[dec.pos:] {
- switch {
- case c == '=' || c == '"':
- dec.pos += p
- dec.unexpectedByte(c)
- return false
- case c <= ' ':
- dec.pos += p
- if dec.pos > start {
- dec.value = line[start:dec.pos]
- }
- return true
- }
- }
- dec.pos = len(line)
- if dec.pos > start {
- dec.value = line[start:dec.pos]
- }
- return true
-
-qvalue:
- const (
- untermQuote = "unterminated quoted value"
- invalidQuote = "invalid quoted value"
- )
-
- hasEsc, esc := false, false
- start = dec.pos
- for p, c := range line[dec.pos+1:] {
- switch {
- case esc:
- esc = false
- case c == '\\':
- hasEsc, esc = true, true
- case c == '"':
- dec.pos += p + 2
- if hasEsc {
- v, ok := unquoteBytes(line[start:dec.pos])
- if !ok {
- dec.syntaxError(invalidQuote)
- return false
- }
- dec.value = v
- } else {
- start++
- end := dec.pos - 1
- if end > start {
- dec.value = line[start:end]
- }
- }
- return true
- }
- }
- dec.pos = len(line)
- dec.syntaxError(untermQuote)
- return false
-}
-
-// Key returns the most recent key found by a call to ScanKeyval. The returned
-// slice may point to internal buffers and is only valid until the next call
-// to ScanRecord. It does no allocation.
-func (dec *Decoder) Key() []byte {
- return dec.key
-}
-
-// Value returns the most recent value found by a call to ScanKeyval. The
-// returned slice may point to internal buffers and is only valid until the
-// next call to ScanRecord. It does no allocation when the value has no
-// escape sequences.
-func (dec *Decoder) Value() []byte {
- return dec.value
-}
-
-// Err returns the first non-EOF error that was encountered by the Scanner.
-func (dec *Decoder) Err() error {
- return dec.err
-}
-
-func (dec *Decoder) syntaxError(msg string) {
- dec.err = &SyntaxError{
- Msg: msg,
- Line: dec.lineNum,
- Pos: dec.pos + 1,
- }
-}
-
-func (dec *Decoder) unexpectedByte(c byte) {
- dec.err = &SyntaxError{
- Msg: fmt.Sprintf("unexpected %q", c),
- Line: dec.lineNum,
- Pos: dec.pos + 1,
- }
-}
-
-// A SyntaxError represents a syntax error in the logfmt input stream.
-type SyntaxError struct {
- Msg string
- Line int
- Pos int
-}
-
-func (e *SyntaxError) Error() string {
- return fmt.Sprintf("logfmt syntax error at pos %d on line %d: %s", e.Pos, e.Line, e.Msg)
-}
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