go/printer: Revert API change of CL 4274075.

Revert changes to printer.Config. Pass in the
nodeSizes map trough an internal helper function.

R=golang-dev, rsc1
CC=golang-dev
https://golang.org/cl/4309042

src/cmd/godoc/godoc.go

@@ -374,7 +374,7 @@ func writeNode(w io.Writer, fset *token.FileSet, x interface{}) {
 	//           with an another printer mode (which is more efficiently
 	//           implemented in the printer than here with another layer)
 	mode := printer.TabIndent | printer.UseSpaces
-	(&printer.Config{Mode: mode, Tabwidth: *tabwidth}).Fprint(&tconv{output: w}, fset, x)
+	(&printer.Config{mode, *tabwidth}).Fprint(&tconv{output: w}, fset, x)
 }
 
 

src/cmd/gofix/main.go

@@ -127,7 +127,7 @@ func processFile(filename string, useStdin bool) os.Error {
 	fmt.Fprintf(os.Stderr, "%s: %s\n", filename, buf.String()[1:])
 
 	buf.Reset()
-	_, err = (&printer.Config{Mode: printerMode, Tabwidth: tabWidth}).Fprint(&buf, fset, file)
+	_, err = (&printer.Config{printerMode, tabWidth}).Fprint(&buf, fset, file)
 	if err != nil {
 		return err
 	}

src/cmd/gofix/main_test.go

@@ -37,7 +37,7 @@ func parseFixPrint(t *testing.T, fn func(*ast.File) bool, desc, in string) (out
 
 	var buf bytes.Buffer
 	buf.Reset()
-	_, err = (&printer.Config{Mode: printerMode, Tabwidth: tabWidth}).Fprint(&buf, fset, file)
+	_, err = (&printer.Config{printerMode, tabWidth}).Fprint(&buf, fset, file)
 	if err != nil {
 		t.Errorf("%s: printing: %v", desc, err)
 		return
@@ -60,7 +60,7 @@ func parseFixPrint(t *testing.T, fn func(*ast.File) bool, desc, in string) (out
 	}
 
 	buf.Reset()
-	_, err = (&printer.Config{Mode: printerMode, Tabwidth: tabWidth}).Fprint(&buf, fset, file)
+	_, err = (&printer.Config{printerMode, tabWidth}).Fprint(&buf, fset, file)
 	if err != nil {
 		t.Errorf("%s: printing: %v", desc, err)
 		return

src/cmd/gofmt/gofmt.go

@@ -103,7 +103,7 @@ func processFile(f *os.File) os.Error {
 	}
 
 	var buf bytes.Buffer
-	_, err = (&printer.Config{Mode: printerMode, Tabwidth: *tabWidth}).Fprint(&buf, fset, file)
+	_, err = (&printer.Config{printerMode, *tabWidth}).Fprint(&buf, fset, file)
 	if err != nil {
 		return err
 	}

src/pkg/go/printer/nodes.go

@@ -1318,9 +1318,9 @@ func (p *printer) nodeSize(n ast.Node, maxSize int) (size int) {
 	// nodeSize computation must be indendent of particular
 	// style so that we always get the same decision; print
 	// in RawFormat
-	cfg := Config{Mode: RawFormat, nodeSizes: p.nodeSizes}
+	cfg := Config{Mode: RawFormat}
 	var buf bytes.Buffer
-	if _, err := cfg.Fprint(&buf, p.fset, n); err != nil {
+	if _, err := cfg.fprint(&buf, p.fset, n, p.nodeSizes); err != nil {
 		return
 	}
 	if buf.Len() <= maxSize {

src/pkg/go/printer/printer.go

@@ -98,15 +98,19 @@ type printer struct {
 	comments        []*ast.CommentGroup // may be nil
 	cindex          int                 // current comment index
 	useNodeComments bool                // if not set, ignore lead and line comments of nodes
+
+	// Cache of already computed node sizes.
+	nodeSizes map[ast.Node]int
 }
 
 
-func (p *printer) init(output io.Writer, cfg *Config, fset *token.FileSet) {
+func (p *printer) init(output io.Writer, cfg *Config, fset *token.FileSet, nodeSizes map[ast.Node]int) {
 	p.output = output
 	p.Config = *cfg
 	p.fset = fset
 	p.errors = make(chan os.Error)
 	p.buffer = make([]whiteSpace, 0, 16) // whitespace sequences are short
+	p.nodeSizes = nodeSizes
 }
 
 
@@ -986,25 +990,13 @@ const (
 
 // A Config node controls the output of Fprint.
 type Config struct {
-	Mode      uint             // default: 0
-	Tabwidth  int              // default: 8
-	nodeSizes map[ast.Node]int // memoized node sizes as computed by nodeSize
+	Mode     uint // default: 0
+	Tabwidth int  // default: 8
 }
 
 
-// Fprint "pretty-prints" an AST node to output and returns the number
-// of bytes written and an error (if any) for a given configuration cfg.
-// Position information is interpreted relative to the file set fset.
-// The node type must be *ast.File, or assignment-compatible to ast.Expr,
-// ast.Decl, ast.Spec, or ast.Stmt.
-//
-func (cfg *Config) Fprint(output io.Writer, fset *token.FileSet, node interface{}) (int, os.Error) {
-	// only if Fprint is called recursively (via nodeSize)
-	// does cfg.nodeSizes exist - set it up otherwise
-	if cfg.nodeSizes == nil {
-		cfg.nodeSizes = make(map[ast.Node]int)
-	}
-
+// fprint implements Fprint and takes a nodesSizes map for setting up the printer state.
+func (cfg *Config) fprint(output io.Writer, fset *token.FileSet, node interface{}, nodeSizes map[ast.Node]int) (int, os.Error) {
 	// redirect output through a trimmer to eliminate trailing whitespace
 	// (Input to a tabwriter must be untrimmed since trailing tabs provide
 	// formatting information. The tabwriter could provide trimming
@@ -1033,7 +1025,7 @@ func (cfg *Config) Fprint(output io.Writer, fset *token.FileSet, node interface{
 
 	// setup printer and print node
 	var p printer
-	p.init(output, cfg, fset)
+	p.init(output, cfg, fset, nodeSizes)
 	go func() {
 		switch n := node.(type) {
 		case ast.Expr:
@@ -1080,6 +1072,17 @@ func (cfg *Config) Fprint(output io.Writer, fset *token.FileSet, node interface{
 }
 
 
+// Fprint "pretty-prints" an AST node to output and returns the number
+// of bytes written and an error (if any) for a given configuration cfg.
+// Position information is interpreted relative to the file set fset.
+// The node type must be *ast.File, or assignment-compatible to ast.Expr,
+// ast.Decl, ast.Spec, or ast.Stmt.
+//
+func (cfg *Config) Fprint(output io.Writer, fset *token.FileSet, node interface{}) (int, os.Error) {
+	return cfg.fprint(output, fset, node, make(map[ast.Node]int))
+}
+
+
 // Fprint "pretty-prints" an AST node to output.
 // It calls Config.Fprint with default settings.
 //