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|
package main
import (
"bytes"
"go/scanner"
"go/token"
)
type editCommand int
const (
keepLine editCommand = iota
addLineBefore
removeLine
)
type edit struct {
line int
cmd editCommand
}
func braceFmt(src []byte) []byte {
var s scanner.Scanner
fset := token.NewFileSet()
file := fset.AddFile("", fset.Base(), len(src))
s.Init(file, src, nil, scanner.ScanComments)
var (
edits []edit
lastNonEmptyLine, lastLBraceLine int
lastOuterRBraceLine = -1
)
for {
pos, tok, _ := s.Scan()
if tok == token.EOF {
break
}
position := fset.Position(pos)
currentLine := position.Line
var nextEdit edit
switch tok {
case token.RBRACE:
if currentLine-lastNonEmptyLine > 1 {
// ......foo
//
// ...}
nextEdit = edit{line: currentLine - 1, cmd: removeLine}
}
if position.Column == 1 {
lastOuterRBraceLine = currentLine
}
if lastLBraceLine == currentLine {
lastLBraceLine = 0
}
case token.LBRACE:
lastLBraceLine = currentLine
if lastOuterRBraceLine == currentLine {
lastOuterRBraceLine = -1
}
default:
if currentLine-lastOuterRBraceLine == 1 {
// }
// func bar() {
nextEdit = edit{line: currentLine, cmd: addLineBefore}
} else if currentLine-lastLBraceLine > 1 && lastNonEmptyLine == lastLBraceLine {
// ...foo() {
//
// ......bar
nextEdit = edit{line: currentLine - 1, cmd: removeLine}
}
}
if nextEdit.cmd != keepLine {
if len(edits) == 0 || edits[0] != nextEdit {
// Store edits in reverse line order: that way line numbers in edits
// won't become invalid when edits get applied.
edits = append([]edit{nextEdit}, edits...)
}
}
lastNonEmptyLine = currentLine
}
srcLines := bytes.Split(src, []byte("\n"))
for _, e := range edits {
i := e.line - 1 // scanner uses 1 based indexing; convert to 0 based
switch e.cmd {
case addLineBefore:
srcLines = append(srcLines[:i], append([][]byte{nil}, srcLines[i:]...)...)
case removeLine:
if len(srcLines[i]) == 0 {
srcLines = append(srcLines[:i], srcLines[i+1:]...)
}
}
}
return bytes.Join(srcLines, []byte("\n"))
}
|
