/usr/share/gocode/src/launchpad.net/gocheck/printer.go is in golang-gocheck-dev 0.0~bzr20131118+85-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 | package gocheck
import (
"bytes"
"go/ast"
"go/parser"
"go/printer"
"go/token"
"os"
)
func indent(s, with string) (r string) {
eol := true
for i := 0; i != len(s); i++ {
c := s[i]
switch {
case eol && c == '\n' || c == '\r':
case c == '\n' || c == '\r':
eol = true
case eol:
eol = false
s = s[:i] + with + s[i:]
i += len(with)
}
}
return s
}
func printLine(filename string, line int) (string, error) {
fset := token.NewFileSet()
file, err := os.Open(filename)
if err != nil {
return "", err
}
fnode, err := parser.ParseFile(fset, filename, file, parser.ParseComments)
if err != nil {
return "", err
}
config := &printer.Config{Mode: printer.UseSpaces, Tabwidth: 4}
lp := &linePrinter{fset: fset, fnode: fnode, line: line, config: config}
ast.Walk(lp, fnode)
result := lp.output.Bytes()
// Comments leave \n at the end.
n := len(result)
for n > 0 && result[n-1] == '\n' {
n--
}
return string(result[:n]), nil
}
type linePrinter struct {
config *printer.Config
fset *token.FileSet
fnode *ast.File
line int
output bytes.Buffer
stmt ast.Stmt
}
func (lp *linePrinter) emit() bool {
if lp.stmt != nil {
lp.trim(lp.stmt)
lp.printWithComments(lp.stmt)
lp.stmt = nil
return true
}
return false
}
func (lp *linePrinter) printWithComments(n ast.Node) {
nfirst := lp.fset.Position(n.Pos()).Line
nlast := lp.fset.Position(n.End()).Line
for _, g := range lp.fnode.Comments {
cfirst := lp.fset.Position(g.Pos()).Line
clast := lp.fset.Position(g.End()).Line
if clast == nfirst-1 && lp.fset.Position(n.Pos()).Column == lp.fset.Position(g.Pos()).Column {
for _, c := range g.List {
lp.output.WriteString(c.Text)
lp.output.WriteByte('\n')
}
}
if cfirst >= nfirst && cfirst <= nlast && n.End() <= g.List[0].Slash {
// The printer will not include the comment if it starts past
// the node itself. Trick it into printing by overlapping the
// slash with the end of the statement.
g.List[0].Slash = n.End() - 1
}
}
node := &printer.CommentedNode{n, lp.fnode.Comments}
lp.config.Fprint(&lp.output, lp.fset, node)
}
func (lp *linePrinter) Visit(n ast.Node) (w ast.Visitor) {
if n == nil {
if lp.output.Len() == 0 {
lp.emit()
}
return nil
}
first := lp.fset.Position(n.Pos()).Line
last := lp.fset.Position(n.End()).Line
if first <= lp.line && last >= lp.line {
// Print the innermost statement containing the line.
if stmt, ok := n.(ast.Stmt); ok {
if _, ok := n.(*ast.BlockStmt); !ok {
lp.stmt = stmt
}
}
if first == lp.line && lp.emit() {
return nil
}
return lp
}
return nil
}
func (lp *linePrinter) trim(n ast.Node) bool {
stmt, ok := n.(ast.Stmt)
if !ok {
return true
}
line := lp.fset.Position(n.Pos()).Line
if line != lp.line {
return false
}
switch stmt := stmt.(type) {
case *ast.IfStmt:
stmt.Body = lp.trimBlock(stmt.Body)
case *ast.SwitchStmt:
stmt.Body = lp.trimBlock(stmt.Body)
case *ast.TypeSwitchStmt:
stmt.Body = lp.trimBlock(stmt.Body)
case *ast.CaseClause:
stmt.Body = lp.trimList(stmt.Body)
case *ast.CommClause:
stmt.Body = lp.trimList(stmt.Body)
case *ast.BlockStmt:
stmt.List = lp.trimList(stmt.List)
}
return true
}
func (lp *linePrinter) trimBlock(stmt *ast.BlockStmt) *ast.BlockStmt {
if !lp.trim(stmt) {
return lp.emptyBlock(stmt)
}
stmt.Rbrace = stmt.Lbrace
return stmt
}
func (lp *linePrinter) trimList(stmts []ast.Stmt) []ast.Stmt {
for i := 0; i != len(stmts); i++ {
if !lp.trim(stmts[i]) {
stmts[i] = lp.emptyStmt(stmts[i])
break
}
}
return stmts
}
func (lp *linePrinter) emptyStmt(n ast.Node) *ast.ExprStmt {
return &ast.ExprStmt{&ast.Ellipsis{n.Pos(), nil}}
}
func (lp *linePrinter) emptyBlock(n ast.Node) *ast.BlockStmt {
p := n.Pos()
return &ast.BlockStmt{p, []ast.Stmt{lp.emptyStmt(n)}, p}
}
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