Use shorter DartElementLocation.

pkg/analysis_server/lib/src/services/index/store/codec.dart

Index: pkg/analysis_server/lib/src/services/index/store/codec.dart
diff --git a/pkg/analysis_server/lib/src/services/index/store/codec.dart b/pkg/analysis_server/lib/src/services/index/store/codec.dart
index b06ec563bb8dead4a416139a0ee543a88d26f50d..9406d9456be1cd92cb068701b33646ba75ba0f12 100644
--- a/pkg/analysis_server/lib/src/services/index/store/codec.dart
+++ b/pkg/analysis_server/lib/src/services/index/store/codec.dart
@@ -68,7 +68,12 @@ class ContextCodec {
  * A helper that encodes/decodes [Element]s to/from integers.
  */
 class ElementCodec {
+  static const KIND_DART = 0;
+  static const KIND_NAME = 1;
+  static const KIND_UNKNOWN = 2;
+
   final StringCodec _stringCodec;
+  final ElementKindCodec _kindCodec = new ElementKindCodec();
 
   /**
    * A table mapping element encodings to a single integer.
@@ -91,10 +96,20 @@ class ElementCodec {
    */
   Element decode(AnalysisContext context, int index) {
     List<int> path = _indexToPath[index];
-    List<String> components = _getLocationComponents(path);
-    ElementLocation location = new ElementLocationImpl.con3(components);
-    Element element = context.getElement(location);
-    return element;
+    if (path[0] == KIND_DART) {
+      String librarySourceEncoding = _stringCodec.decode(path[1]);
+      String unitSourceEncoding = _stringCodec.decode(path[2]);
+      int nameOffset = path[3];
+      ElementKind kind = _kindCodec.decode(path[4]);
+      ElementLocation location = new DartElementLocation(
+          librarySourceEncoding,
+          unitSourceEncoding,
+          nameOffset,
+          kind);
+      return context.getElement(location);
+    }
+    // TODO(scheglov) support for KIND_HTML ?

[Brian Wilkerson, 2014/11/18 15:11:22]

And KIND_NAME.

+    return null;
   }
 
   /**
@@ -128,60 +143,37 @@ class ElementCodec {
     return index;
   }
 
-  List<String> _getLocationComponents(List<int> path) {
-    int length = path.length;
-    List<String> components = new List<String>();
-    for (int i = 0; i < length; i++) {
-      int componentId = path[i];
-      String component = _stringCodec.decode(componentId);
-      if (i < length - 1 && path[i + 1] < 0) {
-        component += '@${(-path[i + 1])}';
-        i++;
-      }
-      components.add(component);
-    }
-    return components;
-  }
-
   /**
    * If [usePath] is `true` then [Source] path should be used instead of URI.
    */
   List<int> _getLocationPath(Element element, bool usePath) {
-    // prepare the location components
-    List<String> components = element.location.components;
-    if (usePath) {
-      LibraryElement library = element.library;
-      if (library != null) {
-        components[0] = library.source.fullName;
-        if (element.enclosingElement is CompilationUnitElement) {
-          components[1] = library.definingCompilationUnit.source.fullName;
-        }
-      }
+    LibraryElement library = element.library;
+    // DynamicElement, NameElement
+    if (library == null) {
+      int nameId = _stringCodec.encode(element.name);
+      return <int>[KIND_NAME, nameId];
     }
-    // encode the location
-    int length = components.length;
-    if (_hasLocalOffset(components)) {
-      List<int> path = new List<int>();
-      for (String component in components) {
-        int atOffset = component.indexOf('@');
-        if (atOffset == -1) {
-          path.add(_stringCodec.encode(component));
-        } else {
-          String preAtString = component.substring(0, atOffset);
-          String atString = component.substring(atOffset + 1);
-          path.add(_stringCodec.encode(preAtString));
-          path.add(-1 * int.parse(atString));
-        }
-      }
-      return path;
-    } else {
-      List<int> path = new List<int>.filled(length, 0);
-      for (int i = 0; i < length; i++) {
-        String component = components[i];
-        path[i] = _stringCodec.encode(component);
+    // normal Element
+    ElementLocation location = element.location;
+    if (location is DartElementLocation) {
+      String librarySourceEncoding;
+      String unitSourceEncoding;
+      if (usePath) {
+        unitSourceEncoding = library.source.fullName;
+        unitSourceEncoding = element.source.fullName;
+      } else {
+        librarySourceEncoding = location.librarySourceEncoding;
+        unitSourceEncoding = location.unitSourceEncoding;
       }
-      return path;
+      int libraryId = _stringCodec.encode(librarySourceEncoding);
+      int unitId = _stringCodec.encode(unitSourceEncoding);
+      // done
+      int nameOffset = location.nameOffset;

[Brian Wilkerson, 2014/11/18 15:11:22]

Do we need to ensure that the name offset is non-negative, or do we produce a
unique offset for every kind of element?

+      int kindId = _kindCodec.encode(location.kind);
+      return <int>[KIND_DART, libraryId, unitId, nameOffset, kindId];
     }
+    // unknown
+    return <int>[KIND_UNKNOWN];
   }
 
   /**
@@ -202,14 +194,24 @@ class ElementCodec {
     int lastId = _stringCodec.encode(lastComponent);
     return <int>[firstId, lastId];
   }
+}
 
-  static bool _hasLocalOffset(List<String> components) {
-    for (String component in components) {
-      if (component.indexOf('@') != -1) {
-        return true;
+
+/**
+ * A helper that encodes/decodes [ElementKind]s to/from integers.
+ */
+class ElementKindCodec {
+  ElementKind decode(int id) {
+    for (ElementKind kind in ElementKind.values) {
+      if (kind.ordinal == id) {
+        return kind;
       }
     }
-    return false;
+    return null;
+  }
+
+  int encode(ElementKind kind) {
+    return kind.ordinal;
   }
 }