drone/git/parser/scanner.go

126 lines
2.7 KiB
Go

// Copyright 2023 Harness, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package parser
import (
"bufio"
"bytes"
"io"
)
type Scanner interface {
Scan() bool
Err() error
Bytes() []byte
Text() string
}
func ScanZeroSeparated(data []byte, atEOF bool) (advance int, token []byte, err error) {
if atEOF && len(data) == 0 {
return 0, nil, nil // Return nothing if at end of file and no data passed
}
if i := bytes.IndexByte(data, 0); i >= 0 {
return i + 1, data[0:i], nil // Split at zero byte
}
if atEOF {
return len(data), data, nil // at the end of file return the data
}
return
}
// ScanLinesWithEOF is a variation of bufio's ScanLine method that returns the line endings.
// https://cs.opensource.google/go/go/+/master:src/bufio/scan.go;l=355;drc=bc2124dab14fa292e18df2937037d782f7868635
func ScanLinesWithEOF(data []byte, atEOF bool) (advance int, token []byte, err error) {
if atEOF && len(data) == 0 {
return 0, nil, nil
}
if i := bytes.IndexByte(data, '\n'); i >= 0 {
// We have a full newline-terminated line.
return i + 1, data[:i+1], nil
}
// If we're at EOF, we have a final, non-terminated line. Return it.
if atEOF {
return len(data), data, nil
}
// Request more data.
return 0, nil, nil
}
func NewScannerWithPeek(r io.Reader, split bufio.SplitFunc) *ScannerWithPeek {
scanner := bufio.NewScanner(r)
scanner.Split(split)
return &ScannerWithPeek{
scanner: scanner,
}
}
type ScannerWithPeek struct {
peeked bool
peekedScanOut bool
nextLine []byte
nextErr error
scanner *bufio.Scanner
}
func (s *ScannerWithPeek) scan() bool {
scanOut := s.scanner.Scan()
s.nextErr = s.scanner.Err()
s.nextLine = s.scanner.Bytes()
return scanOut
}
func (s *ScannerWithPeek) Peek() bool {
if s.peeked {
s.nextLine = nil
s.nextErr = ErrPeekedMoreThanOnce
return false
}
// load next line
scanOut := s.scan()
// set peeked data
s.peeked = true
s.peekedScanOut = scanOut
return scanOut
}
func (s *ScannerWithPeek) Scan() bool {
if s.peeked {
s.peeked = false
return s.peekedScanOut
}
return s.scan()
}
func (s *ScannerWithPeek) Err() error {
return s.nextErr
}
func (s *ScannerWithPeek) Bytes() []byte {
return s.nextLine
}
func (s *ScannerWithPeek) Text() string {
return string(s.nextLine)
}