Add CodeOutput to prepare for emission without in-memory buffers.

pkg/compiler/lib/src/js/printer.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of js;
 
 class Printer extends Indentation implements NodeVisitor {
   final bool shouldCompressOutput;
   leg.Compiler compiler;
-  leg.CodeBuffer outBuffer;
+  CodeBuffer outBuffer;
   bool inForInit = false;
   bool atStatementBegin = false;
   final DanglingElseVisitor danglingElseVisitor;
   final LocalNamer localNamer;
   bool pendingSemicolon = false;
   bool pendingSpace = false;
   DumpInfoTask monitor = null;
 
   static final identifierCharacterRegExp = new RegExp(r'^[a-zA-Z_0-9$]');
   static final expressionContinuationRegExp = new RegExp(r'^[-+([]');
 
   Printer(leg.Compiler compiler, DumpInfoTask monitor,
           { allowVariableMinification: true })
       : shouldCompressOutput = compiler.enableMinification,
         monitor = monitor,
         this.compiler = compiler,
-        outBuffer = new leg.CodeBuffer(),
+        outBuffer = new CodeBuffer(),
         danglingElseVisitor = new DanglingElseVisitor(compiler),
         localNamer = determineRenamer(compiler.enableMinification,
                                       allowVariableMinification);
 
   static LocalNamer determineRenamer(bool shouldCompressOutput,
                                      bool allowVariableMinification) {
     return (shouldCompressOutput && allowVariableMinification)
         ? new MinifyRenamer() : new IdentityNamer();
   }
 
@@ skipping 13 matching lines @@
   int get lastCharCode {
     if (lastAddedString == null) return 0;
     assert(lastAddedString.length != "");
     return lastAddedString.codeUnitAt(lastAddedString.length - 1);
   }
 
   void out(String str) {
     if (str != "") {
       if (pendingSemicolon) {
         if (!shouldCompressOutput) {
-          outBuffer.add(";");
+          outBuffer.write(";");
         } else if (str != "}") {
           // We want to output newline instead of semicolon because it makes
           // the raw stack traces much easier to read and it also makes line-
           // based tools like diff work much better.  JavaScript will
           // automatically insert the semicolon at the newline if it means a
           // parsing error is avoided, so we can only do this trick if the
           // next line is not something that can be glued onto a valid
           // expression to make a new valid expression.
 
           // If we're using the new emitter where most pretty printed code
           // is escaped in strings, it is a lot easier to deal with semicolons
           // than newlines because the former doesn't need escaping.
           if (USE_NEW_EMITTER || expressionContinuationRegExp.hasMatch(str)) {
-            outBuffer.add(";");
+            outBuffer.write(";");
           } else {
-            outBuffer.add("\n");
+            outBuffer.write("\n");
           }
         }
       }
       if (pendingSpace &&
           (!shouldCompressOutput || identifierCharacterRegExp.hasMatch(str))) {
-        outBuffer.add(" ");
+        outBuffer.write(" ");
       }
       pendingSpace = false;
       pendingSemicolon = false;
-      outBuffer.add(str);
+      outBuffer.write(str);
       lastAddedString = str;
     }
   }
 
   void outLn(String str) {
     out(str);
     lineOut();
   }
 
   void outSemicolonLn() {
@@ skipping 921 matching lines @@
   bool visitDefault(Default node) => false;
   bool visitFunctionDeclaration(FunctionDeclaration node) => false;
   bool visitLabeledStatement(LabeledStatement node)
       => node.body.accept(this);
   bool visitLiteralStatement(LiteralStatement node) => true;
 
   bool visitExpression(Expression node) => false;
 }
 
 
-leg.CodeBuffer prettyPrint(Node node, leg.Compiler compiler,
-                           {DumpInfoTask monitor,
-                            allowVariableMinification: true}) {
+CodeBuffer prettyPrint(Node node, leg.Compiler compiler,
+                       {DumpInfoTask monitor,
+                        bool allowVariableMinification: true}) {
   Printer printer =
       new Printer(compiler, monitor,
                   allowVariableMinification: allowVariableMinification);
   printer.visit(node);
   return printer.outBuffer;
 }
 
 
 abstract class LocalNamer {
   String getName(String oldName);
@@ skipping 126 matching lines @@
         codes.add(nthLetter((n ~/ nameSpaceSize) % LETTERS));
       }
       codes.add(charCodes.$0 + digit);
       newName = new String.fromCharCodes(codes);
     }
     assert(new RegExp(r'[a-zA-Z][a-zA-Z0-9]*').hasMatch(newName));
     maps.last[oldName] = newName;
     return newName;
   }
 }