Imported Upstream version 2011-02-01.1upstream/2011-02-01.1

1 files changed, 31 insertions, 11 deletions

diff --git a/src/pkg/go/printer/printer.go b/src/pkg/go/printer/printer.go
index a4ddad50e..34b0c4e2d 100644
--- a/src/pkg/go/printer/printer.go
+++ b/src/pkg/go/printer/printer.go
@@ -58,6 +58,15 @@ var infinity = 1 << 30
 var ignoreMultiLine = new(bool)
 
 
+// A pmode value represents the current printer mode.
+type pmode int
+
+const (
+	inLiteral pmode = 1 << iota
+	noExtraLinebreak
+)
+
+
 type printer struct {
 	// Configuration (does not change after initialization)
 	output io.Writer
@@ -69,7 +78,7 @@ type printer struct {
 	nesting int         // nesting level (0: top-level (package scope), >0: functions/decls.)
 	written int         // number of bytes written
 	indent  int         // current indentation
-	escape  bool        // true if in escape sequence
+	mode    pmode       // current printer mode
 	lastTok token.Token // the last token printed (token.ILLEGAL if it's whitespace)
 
 	// Buffered whitespace
@@ -162,7 +171,7 @@ func (p *printer) write(data []byte) {
 			p.pos.Line++
 			p.pos.Column = 1
 
-			if !p.escape {
+			if p.mode&inLiteral == 0 {
 				// write indentation
 				// use "hard" htabs - indentation columns
 				// must not be discarded by the tabwriter
@@ -211,7 +220,7 @@ func (p *printer) write(data []byte) {
 			}
 
 		case tabwriter.Escape:
-			p.escape = !p.escape
+			p.mode ^= inLiteral
 
 			// ignore escape chars introduced by printer - they are
 			// invisible and must not affect p.pos (was issue #1089)
@@ -272,7 +281,7 @@ func (p *printer) writeItem(pos token.Position, data []byte, tag HTMLTag) {
 			// (used when printing merged ASTs of different files
 			// e.g., the result of ast.MergePackageFiles)
 			p.indent = 0
-			p.escape = false
+			p.mode = 0
 			p.buffer = p.buffer[0:0]
 			fileChanged = true
 		}
@@ -683,9 +692,13 @@ func (p *printer) intersperseComments(next token.Position, tok token.Token) (dro
 			// follows on the same line: separate with an extra blank
 			p.write([]byte{' '})
 		}
-		// ensure that there is a newline after a //-style comment
-		// or if we are before a closing '}' or at the end of a file
-		return p.writeCommentSuffix(last.Text[1] == '/' || tok == token.RBRACE || tok == token.EOF)
+		// ensure that there is a line break after a //-style comment,
+		// before a closing '}' unless explicitly disabled, or at eof
+		needsLinebreak :=
+			last.Text[1] == '/' ||
+				tok == token.RBRACE && p.mode&noExtraLinebreak == 0 ||
+				tok == token.EOF
+		return p.writeCommentSuffix(needsLinebreak)
 	}
 
 	// no comment was written - we should never reach here since
@@ -787,6 +800,9 @@ func (p *printer) print(args ...interface{}) {
 		var tok token.Token
 
 		switch x := f.(type) {
+		case pmode:
+			// toggle printer mode
+			p.mode ^= x
 		case whiteSpace:
 			if x == ignore {
 				// don't add ignore's to the buffer; they
@@ -818,10 +834,14 @@ func (p *printer) print(args ...interface{}) {
 				data = x.Value
 			}
 			// escape all literals so they pass through unchanged
-			// (note that valid Go programs cannot contain esc ('\xff')
-			// bytes since they do not appear in legal UTF-8 sequences)
-			// TODO(gri): do this more efficiently.
-			data = []byte("\xff" + string(data) + "\xff")
+			// (note that valid Go programs cannot contain
+			// tabwriter.Escape bytes since they do not appear in
+			// legal UTF-8 sequences)
+			escData := make([]byte, 0, len(data)+2)
+			escData = append(escData, tabwriter.Escape)
+			escData = append(escData, data...)
+			escData = append(escData, tabwriter.Escape)
+			data = escData
 			tok = x.Kind
 		case token.Token:
 			s := x.String()