Cache ElementLocation instance and index key/location ids.

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

 // Copyright (c) 2014, 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 services.src.index.store.codec;
 
 import 'dart:collection';
 
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/index/store/collection.dart';
@@ skipping 86 matching lines @@
     return element;
   }
 
   /**
    * Returns a unique integer that corresponds to the given [Element].
    *
    * If [forKey] is `true` then [element] is a part of a key, so it should use
    * file paths instead of [Element] location URIs.
    */
   int encode(Element element, bool forKey) {
-    List<int> path = _getLocationPath(element, forKey);
-    int index = _pathToIndex[path];
-    if (index == null) {
-      index = _indexToPath.length;
-      _pathToIndex[path] = index;
-      _indexToPath.add(path);
+    ElementLocationImpl location = element.location;
+    // check the location has a cached id
+    if (!identical(location.indexOwner, this)) {
+      location.indexKeyId = null;
+      location.indexLocationId = null;
     }
+    if (forKey) {
+      int id = location.indexKeyId;
+      if (id != null) {
+        return id;
+      }
+    } else {
+      int id = location.indexLocationId;
+      if (id != null) {
+        return id;
+      }
+    }
+    // prepare an id
+    List<int> path = _getLocationPath(element, location, forKey);
+    int index = _encodePath(path);
+    // put the id into the location
+    if (forKey) {
+      location.indexOwner = this;
+      location.indexKeyId = index;
+    } else {
+      location.indexOwner = this;
+      location.indexLocationId = index;
+    }
+    // done
     return index;
   }
 
   /**
    * Returns an integer that corresponds to an approximated location of [element].
    */
   int encodeHash(Element element) {
     List<int> path = _getLocationPathLimited(element);
+    int index = _encodePath(path);
+    return index;
+  }
+
+  int _encodePath(List<int> path) {
     int index = _pathToIndex[path];
     if (index == null) {
       index = _indexToPath.length;
       _pathToIndex[path] = index;
       _indexToPath.add(path);
     }
     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) {
+  List<int> _getLocationPath(Element element, ElementLocation location,
+      bool usePath) {
     // prepare the location components
-    List<String> components = element.location.components;
+    List<String> components = location.components;
     if (usePath) {
       LibraryElement library = element.library;
       if (library != null) {
+        components = components.toList();
         components[0] = library.source.fullName;
         if (element.enclosingElement is CompilationUnitElement) {
           components[1] = library.definingCompilationUnit.source.fullName;
         }
       }
     }
     // encode the location
     int length = components.length;
     if (_hasLocalOffset(components)) {
       List<int> path = new List<int>();
@@ skipping 94 matching lines @@
   int encode(String name) {
     int index = nameToIndex[name];
     if (index == null) {
       index = _indexToName.length;
       nameToIndex[name] = index;
       _indexToName.add(name);
     }
     return index;
   }
 }