Add ImportElement.namespace and use it in completion.

R=brianwilkerson@google.com

Change-Id: I58cadf0e3239ad4ae8584d79485f4d9ebda10eba
Reviewed-on: https://dart-review.googlesource.com/54064
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

Author: scheglov

pkg/analysis_server/lib/src/services/completion/dart/library_member_contributor.dart

@@ -57,7 +57,7 @@ class LibraryMemberContributor extends DartCompletionContributor {
           LibraryElementSuggestionBuilder builder =
               new LibraryElementSuggestionBuilder(containingLibrary,
                   CompletionSuggestionKind.INVOCATION, typesOnly, instCreation);
-          for (var element in library.exportNamespace.definedNames.values) {
+          for (var element in importElem.namespace.definedNames.values) {
             element.accept(builder);
           }
           suggestions.addAll(builder.suggestions);

pkg/analysis_server/lib/src/services/correction/namespace.dart

@@ -114,8 +114,7 @@ ImportElement internal_getImportElement(
     if (importElementsMap.containsKey(importElement)) {
       continue;
     }
-    Namespace namespace =
-        new NamespaceBuilder().createImportNamespaceForDirective(importElement);
+    Namespace namespace = importElement.namespace;
     Set<Element> elements = new Set.from(namespace.definedNames.values);
     importElementsMap[importElement] = elements;
   }

pkg/analysis_server/lib/src/services/correction/util.dart

@@ -16,7 +16,6 @@ import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart';
 import 'package:analyzer/src/generated/engine.dart';
-import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart'
     show SourceChange, SourceEdit;
@@ -342,9 +341,7 @@ int getExpressionPrecedence(AstNode node) {
  * Returns the namespace of the given [ImportElement].
  */
 Map<String, Element> getImportNamespace(ImportElement imp) {
-  NamespaceBuilder builder = new NamespaceBuilder();
-  Namespace namespace = builder.createImportNamespaceForDirective(imp);
-  return namespace.definedNames;
+  return imp.namespace.definedNames;
 }
 
 /**

pkg/analysis_server/test/completion_test.dart

@@ -1606,25 +1606,17 @@ main() {
         extraFiles: sources,
         failingTests: '1');
 
-    buildTests(
-        'test_importPrefix_hideCombinator',
-        '''
+    buildTests('test_importPrefix_hideCombinator', '''
 import 'dart:math' as math hide PI;
 main() {
   math.!1
-}''',
-        <String>["1-PI", "1+LN10"],
-        failingTests: '1');
+}''', <String>["1-PI", "1+LN10"]);
 
-    buildTests(
-        'test_importPrefix_showCombinator',
-        '''
+    buildTests('test_importPrefix_showCombinator', '''
 import 'dart:math' as math show PI;
 main() {
   math.!1
-}''',
-        <String>["1+PI", "1-LN10"],
-        failingTests: '1');
+}''', <String>["1+PI", "1-LN10"]);
 
     sources.clear();
     sources["/lib.dart"] = '''

pkg/analysis_server/test/services/completion/dart/library_member_contributor_test.dart

@@ -161,11 +161,7 @@ main() {
     assertNotSuggested('B');
   }
 
-  @failingTest
   test_PrefixedIdentifier_library_import_withShow() async {
-    // As it is designed now, I think we should not suggest B.
-    // However an alternative design could be suggesting it, but updating show.
-    // This could be a part of project-wide suggesting and auto-importing.
     addSource('/a.dart', r'''
 class A {}
 class B {}

pkg/analyzer/lib/dart/element/element.dart

@@ -1457,6 +1457,11 @@ abstract class ImportElement implements Element, UriReferencedElement {
    */
   bool get isDeferred;
 
+  /**
+   * The [Namespace] that this directive contributes to the containing library.
+   */
+  Namespace get namespace;
+
   /**
    * Return the prefix that was specified as part of the import directive, or
    * `null` if there was no prefix specified.

pkg/analyzer/lib/src/dart/analysis/search.dart

@@ -14,7 +14,6 @@ import 'package:analyzer/src/dart/analysis/index.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/member.dart';
-import 'package:analyzer/src/dart/resolver/scope.dart' show NamespaceBuilder;
 import 'package:analyzer/src/summary/idl.dart';
 import 'package:collection/collection.dart';
 
@@ -823,11 +822,7 @@ class _ImportElementReferencesVisitor extends RecursiveAstVisitor {
   _ImportElementReferencesVisitor(
       ImportElement element, this.enclosingUnitElement)
       : importElement = element {
-    importedElements = new NamespaceBuilder()
-        .createImportNamespaceForDirective(element)
-        .definedNames
-        .values
-        .toSet();
+    importedElements = element.namespace.definedNames.values.toSet();
   }
 
   @override

pkg/analyzer/lib/src/dart/element/element.dart

@@ -5790,6 +5790,11 @@ class ImportElementImpl extends UriReferencedElementImpl
    */
   String _selectedUri;
 
+  /**
+   * The cached value of [namespace].
+   */
+  Namespace _namespace;
+
   /**
    * Initialize a newly created import element at the given [offset].
    * The offset may be `-1` if the import is synthetic.
@@ -5939,6 +5944,12 @@ class ImportElementImpl extends UriReferencedElementImpl
     return offset;
   }
 
+  @override
+  Namespace get namespace {
+    return _namespace ??=
+        new NamespaceBuilder().createImportNamespaceForDirective(this);
+  }
+
   PrefixElement get prefix {
     if (_prefix == null) {
       if (_kernel != null && _kernel.name != null) {

pkg/analyzer/lib/src/dart/element/handle.dart

@@ -762,6 +762,9 @@ class ImportElementHandle extends ElementHandle implements ImportElement {
   @override
   ElementKind get kind => ElementKind.IMPORT;
 
+  @override
+  Namespace get namespace => actualElement.namespace;
+
   @override
   PrefixElement get prefix => actualElement.prefix;
 

pkg/analyzer/lib/src/dart/resolver/scope.dart

@@ -488,13 +488,11 @@ class LibraryImportScope extends Scope {
    * later reference.
    */
   void _createImportedNamespaces() {
-    NamespaceBuilder builder = new NamespaceBuilder();
     List<ImportElement> imports = _definingLibrary.imports;
     int count = imports.length;
     _importedNamespaces = new List<Namespace>(count);
     for (int i = 0; i < count; i++) {
-      _importedNamespaces[i] =
-          builder.createImportNamespaceForDirective(imports[i]);
+      _importedNamespaces[i] = imports[i].namespace;
     }
   }