Support unmapped areas in source maps.

pkg/source_maps/lib/parser.dart

 // Copyright (c) 2013, 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.
 
 /// Contains the top-level function to parse source maps version 3.
 library source_maps.parser;
 
 import 'dart:convert';
 
 import 'span.dart';
@@ skipping 167 matching lines @@
       // following order:
       //   0: the starting column in the current line of the generated file
       //   1: the id of the original source file
       //   2: the starting line in the original source
       //   3: the starting column in the original source
       //   4: the id of the original symbol name
       // The values are relative to the previous encountered values.
       if (tokenizer.nextKind.isNewSegment) throw _segmentError(0, line);
       column += tokenizer._consumeValue();
       if (!tokenizer.nextKind.isValue) {
-        entries.add(new TargetEntry(column, srcUrlId, srcLine, srcColumn));
+        entries.add(new TargetEntry(column));
       } else {
         srcUrlId += tokenizer._consumeValue();
         if (srcUrlId >= urls.length) {
           throw new StateError(
               'Invalid source url id. $targetUrl, $line, $srcUrlId');
         }
         if (!tokenizer.nextKind.isValue) throw _segmentError(2, line);
         srcLine += tokenizer._consumeValue();
         if (!tokenizer.nextKind.isValue) throw _segmentError(3, line);
         srcColumn += tokenizer._consumeValue();
         if (!tokenizer.nextKind.isValue) {
           entries.add(new TargetEntry(column, srcUrlId, srcLine, srcColumn));
         } else {
           srcNameId += tokenizer._consumeValue();
           if (srcNameId >= names.length) {
             throw new StateError(
                 'Invalid name id: $targetUrl, $line, $srcNameId');
           }
-          entries.add(
-              new TargetEntry(column, srcUrlId, srcLine, srcColumn, srcNameId));
+          entries.add(new TargetEntry(column, srcUrlId, srcLine, srcColumn,
+              srcNameId));
         }
       }
       if (tokenizer.nextKind.isNewSegment) tokenizer._consumeNewSegment();
     }
     if (!entries.isEmpty) {
       lines.add(new TargetLineEntry(line, entries));
     }
   }
 
   _segmentError(int seen, int line) => new StateError(
@@ skipping 16 matching lines @@
   TargetEntry _findColumn(int line, int column, TargetLineEntry lineEntry) {
     if (lineEntry == null || lineEntry.entries.length == 0) return null;
     if (lineEntry.line != line) return lineEntry.entries.last;
     var entries = lineEntry.entries;
     int index = binarySearch(entries, (e) => e.column > column);
     return (index <= 0) ? null : entries[index - 1];
   }
 
   Span spanFor(int line, int column, {Map<String, SourceFile> files}) {
     var entry = _findColumn(line, column, _findLine(line));
-    if (entry == null) return null;
+    if (entry == null || entry.sourceUrlId == null) return null;
     var url = urls[entry.sourceUrlId];
     if (files != null && files[url] != null) {
       var file = files[url];
       var start = file.getOffset(entry.sourceLine, entry.sourceColumn);
       if (entry.sourceNameId != null) {
         var text = names[entry.sourceNameId];
         return new FileSpan(files[url], start, start + text.length, true);
       } else {
         return new FileSpan(files[url], start);
       }
@@ skipping 59 matching lines @@
 }
 
 /// A target segment entry read from a source map
 class TargetEntry {
   final int column;
   final int sourceUrlId;
   final int sourceLine;
   final int sourceColumn;
   final int sourceNameId;
 
-  TargetEntry(this.column, this.sourceUrlId, this.sourceLine,
-      this.sourceColumn, [this.sourceNameId]);
+  TargetEntry(this.column, [this.sourceUrlId, this.sourceLine,
+      this.sourceColumn, this.sourceNameId]);
 
   String toString() => '$runtimeType: '
       '($column, $sourceUrlId, $sourceLine, $sourceColumn, $sourceNameId)';
 }
 
 /** A character iterator over a string that can peek one character ahead. */
 class _MappingTokenizer implements Iterator<String> {
   final String _internal;
   final int _length;
   int index = -1;
@@ skipping 44 matching lines @@
   static const _TokenKind EOF = const _TokenKind(isEof: true);
   static const _TokenKind VALUE = const _TokenKind();
   final bool isNewLine;
   final bool isNewSegment;
   final bool isEof;
   bool get isValue => !isNewLine && !isNewSegment && !isEof;
 
   const _TokenKind(
       {this.isNewLine: false, this.isNewSegment: false, this.isEof: false});
 }