Introduce CodeBuffer as StringBuffer replacement in compiler.

lib/compiler/implementation/source_map_builder.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.
 
 #library('source_map_builder');
 
 #import('dart:json');
 
 #import('source_file.dart');
-#import('ssa/ssa.dart');
 
 class SourceMapBuilder {
   static final int VLQ_BASE_SHIFT = 5;
   static final int VLQ_BASE_MASK = (1 << 5) - 1;
   static final int VLQ_CONTINUATION_BIT = 1 << 5;
   static final int VLQ_CONTINUATION_MASK = 1 << 5;
   static final String BASE64_DIGITS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmn'
                                       'opqrstuvwxyz0123456789+/';
 
-  List<_Block> blocks;
+  List<_Entry> entries;
 
   Map<String, int> sourceUrlMap;
   List<String> sourceUrlList;
   Map<String, int> sourceNameMap;
   List<String> sourceNameList;
 
   int previousTargetLine;
   int previousTargetColumn;
   int previousSourceUrlIndex;
   int previousSourceLine;
   int previousSourceColumn;
   int previousSourceNameIndex;
   bool firstEntryInLine;
 
   SourceMapBuilder() {
-    blocks = new List<_Block>();
+    entries = new List<_Entry>();
 
     sourceUrlMap = new Map<String, int>();
     sourceUrlList = new List<String>();
     sourceNameMap = new Map<String, int>();
     sourceNameList = new List<String>();
 
     previousTargetLine = 0;
     previousTargetColumn = 0;
     previousSourceUrlIndex = 0;
     previousSourceLine = 0;
     previousSourceColumn = 0;
     previousSourceNameIndex = 0;
     firstEntryInLine = true;
   }
 
-  void addCodeBlock(List<SourceMappingEntry> sourceMappings, int offset) {
-    if (sourceMappings !== null) {
-      blocks.add(new _Block(sourceMappings, offset));
-    }
+  void addMapping(SourceFile sourceFile, int sourceOffset, String sourceName,
+                  int targetOffset) {
+    entries.add(new _Entry(sourceFile, sourceOffset, sourceName, targetOffset));
   }
 
   String build(SourceFile targetFile) {
     StringBuffer buffer = new StringBuffer();
     buffer.add('{\n');
     buffer.add('  "version": 3,\n');
     buffer.add('  "mappings": "');
-    blocks.forEach((_Block block) {
-      block.sourceMapings.forEach((SourceMappingEntry entry) {
-        writeEntry(entry, targetFile, block.offset, buffer);
-      });
-    });
+    entries.forEach((_Entry entry) => writeEntry(entry, targetFile, buffer));
     buffer.add('",\n');
     buffer.add('  "sources": ');
     JSON.printOn(sourceUrlList, buffer);
     buffer.add(',\n');
     buffer.add('  "names": ');
     JSON.printOn(sourceNameList, buffer);
     buffer.add('\n}\n');
     return buffer.toString();
   }
 
-  void writeEntry(SourceMappingEntry entry,
-                  SourceFile targetFile,
-                  int targetOffset,
-                  StringBuffer output) {
+  void writeEntry(_Entry entry, SourceFile targetFile, StringBuffer output) {
     if (entry.sourceFile === null) {
       return;
     }
-    int totalTargetOffset = targetOffset + entry.targetOffset;
-    int targetLine = targetFile.getLine(totalTargetOffset);
-    int targetColumn = targetFile.getColumn(targetLine, totalTargetOffset);
+
+    int targetLine = targetFile.getLine(entry.targetOffset);
+    int targetColumn = targetFile.getColumn(targetLine, entry.targetOffset);
     String sourceUrl = entry.sourceFile.filename;
     int sourceLine = entry.sourceFile.getLine(entry.sourceOffset);
     int sourceColumn = entry.sourceFile.getColumn(sourceLine,
                                                   entry.sourceOffset);
     String sourceName = entry.sourceName;
 
     if (targetLine > previousTargetLine) {
       for (int i = previousTargetLine; i < targetLine; ++i) {
         output.add(';');
       }
@@ skipping 52 matching lines @@
       int digit = value & VLQ_BASE_MASK;
       value >>= VLQ_BASE_SHIFT;
       if (value > 0) {
         digit |= VLQ_CONTINUATION_BIT;
       }
       output.add(BASE64_DIGITS[digit]);
     } while (value > 0);
   }
 }
 
-class _Block {
-  List<SourceMappingEntry> sourceMapings;
-  int offset;
-  _Block(this.sourceMapings, this.offset);
-}
-
-class SourceMappingEntry {
+class _Entry {
   SourceFile sourceFile;
   int sourceOffset;
+  String sourceName;
   int targetOffset;
-  String sourceName;
-
-  SourceMappingEntry(this.sourceFile,
-                     this.sourceOffset,
-                     this.targetOffset,
-                     [this.sourceName]);
+  _Entry(this.sourceFile, this.sourceOffset, this.sourceName,
+         this.targetOffset);
 }