Convert server to use RangeFactory

pkg/analyzer_plugin/lib/utilities/range_factory.dart

Index: pkg/analyzer_plugin/lib/utilities/range_factory.dart
diff --git a/pkg/analyzer_plugin/lib/utilities/range_factory.dart b/pkg/analyzer_plugin/lib/utilities/range_factory.dart
index a875abf3f09f2d0c34b734ead7ddaf9024b68e70..feb3b7c416141ca80e2d31bd0e6263fe4bfbf06b 100644
--- a/pkg/analyzer_plugin/lib/utilities/range_factory.dart
+++ b/pkg/analyzer_plugin/lib/utilities/range_factory.dart
@@ -81,6 +81,34 @@ class RangeFactory {
   }
 
   /**
+   * Return a source range whose length is the same as the given [range], but
+   * whose offset is the offset of the given [range] with [offset] added to it.
+   */
+  SourceRange offsetBy(SourceRange range, int offset) {
+    return new SourceRange(range.offset + offset, range.length);
+  }
+
+  /**
+   * Return a source range that starts at the given [offset] and ends at the
+   * given [endIndex].
+   */
+  SourceRange offsetEndIndex(int offset, int endIndex) {

[scheglov, 2017/05/09 16:04:14]

Drop "Index" for consistency with other methods, like "startEnd"?

[Brian Wilkerson, 2017/05/09 16:51:56]

So far, "end" means that 'end' will be invoked on the corresponding
SyntacticEntity (and "start" means 'start' will be invoked). But in this case
the parameter is an 'int'. The other places we take an 'int' we use "length"
(because it's used as the length of the range). I was trying to find something
that would be consistent with that pattern.

If I drop the "Index", then I can't write a method to create a range from the
start of an entity to a given ending offset because it would want to be named
startEnd, and then the name has two meanings. And I'd rather not make the
parameter's type 'Object' because it doesn't help the user. I'd use overloading
if Dart supported it, but...

Thoughts?

+    int length = endIndex - offset;
+    return new SourceRange(offset, length);
+  }
+
+//  /**
+//   * Return a source range that starts at the start of [leftEntity] and ends at
+//   * the given [endIndex].
+//   */
+//  SourceRange startEndIndex(
+//      SyntacticEntity leftEntity, int endIndex) {
+//    int offset = leftEntity.offset;
+//    int length = endIndex - offset;
+//    return new SourceRange(offset, length);
+//  }
+
+  /**
    * Return a source range that starts at the start of [leftEntity] and ends at
    * the end of [rightEntity].
    */