diff options
Diffstat (limited to 'vendor/github.com/go-logfmt/logfmt/decode.go')
-rw-r--r-- | vendor/github.com/go-logfmt/logfmt/decode.go | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/vendor/github.com/go-logfmt/logfmt/decode.go b/vendor/github.com/go-logfmt/logfmt/decode.go new file mode 100644 index 0000000..04e0eff --- /dev/null +++ b/vendor/github.com/go-logfmt/logfmt/decode.go @@ -0,0 +1,237 @@ +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) +} |