Port two completion contributors for use by plugins

pkg/analyzer_plugin/lib/src/utilities/completion/suggestion_builder.dart

Index: pkg/analyzer_plugin/lib/src/utilities/completion/suggestion_builder.dart
diff --git a/pkg/analyzer_plugin/lib/src/utilities/completion/suggestion_builder.dart b/pkg/analyzer_plugin/lib/src/utilities/completion/suggestion_builder.dart
new file mode 100644
index 0000000000000000000000000000000000000000..24726965fe8d048702db386eee7086fdab13d7d2
--- /dev/null
+++ b/pkg/analyzer_plugin/lib/src/utilities/completion/suggestion_builder.dart
@@ -0,0 +1,193 @@
+// Copyright (c) 2017, 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.
+
+import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/dart/element/type.dart';
+import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/src/generated/utilities_dart.dart';
+import 'package:analyzer_plugin/protocol/protocol_common.dart'
+    hide Element, ElementKind;
+import 'package:analyzer_plugin/src/utilities/documentation.dart';
+import 'package:analyzer_plugin/utilities/analyzer_converter.dart';
+import 'package:analyzer_plugin/utilities/completion/relevance.dart';
+import 'package:analyzer_plugin/utilities/completion/suggestion_builder.dart';
+import 'package:front_end/src/base/source.dart' show Source;
+import 'package:front_end/src/base/uri_kind.dart';
+
+/**
+ * An object used to build code completion suggestions for Dart code.
+ */
+class SuggestionBuilderImpl implements SuggestionBuilder {
+  /**
+   * The resource provider used to access the file system.
+   */
+  final ResourceProvider resourceProvider;
+
+  /**
+   * The converter used to convert analyzer objects to protocol objects.
+   */
+  final AnalyzerConverter converter = new AnalyzerConverter();
+
+  /**
+   * Initialize a newly created suggestion builder.
+   */
+  SuggestionBuilderImpl(this.resourceProvider);
+
+  /**
+   * Add default argument list text and ranges based on the given [requiredParams]
+   * and [namedParams].
+   */
+  void addDefaultArgDetails(
+      CompletionSuggestion suggestion,
+      Element element,
+      Iterable<ParameterElement> requiredParams,
+      Iterable<ParameterElement> namedParams) {
+    // Copied from analysis_server/lib/src/services/completion/dart/suggestion_builder.dart
+    StringBuffer buffer = new StringBuffer();
+    List<int> ranges = <int>[];
+
+    int offset;
+
+    for (ParameterElement param in requiredParams) {
+      if (buffer.isNotEmpty) {
+        buffer.write(', ');
+      }
+      offset = buffer.length;
+      String name = param.name;
+      buffer.write(name);
+      ranges.addAll([offset, name.length]);
+    }
+
+    for (ParameterElement param in namedParams) {
+      if (param.isRequired) {
+        if (buffer.isNotEmpty) {
+          buffer.write(', ');
+        }
+        String name = param.name;
+        buffer.write('$name: ');
+        offset = buffer.length;
+        String defaultValue = 'null'; // originally _getDefaultValue(param)
+        buffer.write(defaultValue);
+        ranges.addAll([offset, defaultValue.length]);
+      }
+    }
+
+    suggestion.defaultArgumentListString =
+        buffer.isNotEmpty ? buffer.toString() : null;
+    suggestion.defaultArgumentListTextRanges =
+        ranges.isNotEmpty ? ranges : null;
+  }
+
+  @override
+  CompletionSuggestion forElement(Element element,
+      {String completion,
+      CompletionSuggestionKind kind: CompletionSuggestionKind.INVOCATION,
+      int relevance: DART_RELEVANCE_DEFAULT,
+      Source importForSource}) {
+    // Copied from analysis_server/lib/src/services/completion/dart/suggestion_builder.dart
+    if (element == null) {
+      return null;
+    }
+    if (element is ExecutableElement && element.isOperator) {
+      // Do not include operators in suggestions
+      return null;
+    }
+    if (completion == null) {
+      completion = element.displayName;
+    }
+    bool isDeprecated = element.isDeprecated;
+    CompletionSuggestion suggestion = new CompletionSuggestion(
+        kind,
+        isDeprecated ? DART_RELEVANCE_LOW : relevance,
+        completion,
+        completion.length,
+        0,
+        isDeprecated,
+        false);
+
+    // Attach docs.
+    String doc = removeDartDocDelimiters(element.documentationComment);
+    suggestion.docComplete = doc;
+    suggestion.docSummary = getDartDocSummary(doc);
+
+    suggestion.element = converter.convertElement(element);
+    Element enclosingElement = element.enclosingElement;
+    if (enclosingElement is ClassElement) {
+      suggestion.declaringType = enclosingElement.displayName;
+    }
+    suggestion.returnType = getReturnTypeString(element);
+    if (element is ExecutableElement && element is! PropertyAccessorElement) {
+      suggestion.parameterNames = element.parameters
+          .map((ParameterElement parameter) => parameter.name)
+          .toList();
+      suggestion.parameterTypes =
+          element.parameters.map((ParameterElement parameter) {
+        DartType paramType = parameter.type;
+        // Gracefully degrade if type not resolved yet
+        return paramType != null ? paramType.displayName : 'var';
+      }).toList();
+
+      Iterable<ParameterElement> requiredParameters = element.parameters.where(
+          (ParameterElement param) =>
+              param.parameterKind == ParameterKind.REQUIRED);
+      suggestion.requiredParameterCount = requiredParameters.length;
+
+      Iterable<ParameterElement> namedParameters = element.parameters.where(
+          (ParameterElement param) =>
+              param.parameterKind == ParameterKind.NAMED);
+      suggestion.hasNamedParameters = namedParameters.isNotEmpty;
+
+      addDefaultArgDetails(
+          suggestion, element, requiredParameters, namedParameters);
+    }
+    if (importForSource != null) {
+      String srcPath =
+          resourceProvider.pathContext.dirname(importForSource.fullName);
+      LibraryElement libElem = element.library;
+      if (libElem != null) {
+        Source libSource = libElem.source;
+        if (libSource != null) {
+          UriKind uriKind = libSource.uriKind;
+          if (uriKind == UriKind.DART_URI) {
+            suggestion.importUri = libSource.uri.toString();
+          } else if (uriKind == UriKind.PACKAGE_URI) {
+            suggestion.importUri = libSource.uri.toString();
+          } else if (uriKind == UriKind.FILE_URI &&
+              element.source.uriKind == UriKind.FILE_URI) {
+            try {
+              suggestion.importUri = resourceProvider.pathContext
+                  .relative(libSource.fullName, from: srcPath);
+            } catch (_) {
+              // ignored
+            }
+          }
+        }
+      }
+      if (suggestion.importUri == null) {
+        // Do not include out of scope suggestions
+        // for which we cannot determine an import
+        return null;
+      }
+    }
+    return suggestion;
+  }
+
+  String getReturnTypeString(Element element) {
+    // Copied from analysis_server/lib/src/protocol_server.dart
+    if (element is ExecutableElement) {
+      if (element.kind == ElementKind.SETTER) {
+        return null;
+      } else {
+        return element.returnType?.toString();
+      }
+    } else if (element is VariableElement) {
+      DartType type = element.type;
+      return type != null ? type.displayName : 'dynamic';
+    } else if (element is FunctionTypeAliasElement) {
+      return element.returnType.toString();
+    } else {
+      return null;
+    }
+  }
+}