pkg/analysis_server/lib/src/services/completion/dart/utilities.dart - sdk.git - Git at Google

 // 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.

 /// A collection of utility methods used by completion contributors.
 import 'package:analysis_server/src/protocol_server.dart'
     show CompletionSuggestion, Location;
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_ast_factory.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/ast/token.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart' as protocol
     show Element, ElementKind;
 import 'package:meta/meta.dart';

 /// The name of the type `dynamic`;
 const DYNAMIC = 'dynamic';

 /// Sort by relevance first, highest to lowest, and then by the completion
 /// alphabetically.
 Comparator<CompletionSuggestion> completionComparator = (a, b) {
   if (a.relevance == b.relevance) {
     return a.completion.compareTo(b.completion);
   }
   return b.relevance.compareTo(a.relevance);
 };

 /// A marker used in place of `null` when a function has no return type.
 final TypeName NO_RETURN_TYPE = astFactory.typeName(
     astFactory.simpleIdentifier(StringToken(TokenType.IDENTIFIER, '', 0)),
     null);

 /// 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) {
   var sb = StringBuffer();
   var ranges = <int>[];

   int offset;

   for (var param in requiredParams) {
     if (sb.isNotEmpty) {
       sb.write(', ');
     }
     offset = sb.length;

     if (param.type is FunctionType) {
       FunctionType type = param.type;

       var rangeStart = offset;
       int rangeLength;

       // todo (pq): consider adding ranges for params
       // pending: https://github.com/dart-lang/sdk/issues/40207
       // (types in closure param completions make this UX awkward)
       final parametersString = buildClosureParameters(type);
       final blockBuffer = StringBuffer(parametersString);

       blockBuffer.write(' ');

       // todo (pq): consider refactoring to share common logic w/
       //  ArgListContributor.buildClosureSuggestions
       final returnType = type.returnType;
       if (returnType.isVoid) {
         blockBuffer.write('{');
         rangeStart = sb.length + blockBuffer.length;
         blockBuffer.write(' }');
         rangeLength = 1;
       } else {
         final returnValue = returnType.isDartCoreBool ? 'false' : 'null';
         blockBuffer.write('=> ');
         rangeStart = sb.length + blockBuffer.length;
         blockBuffer.write(returnValue);
         rangeLength = returnValue.length;
       }

       sb.write(blockBuffer);
       ranges.addAll([rangeStart, rangeLength]);
     } else {
       var name = param.name;
       sb.write(name);
       ranges.addAll([offset, name.length]);
     }
   }

   for (var param in namedParams) {
     if (param.hasRequired) {
       if (sb.isNotEmpty) {
         sb.write(', ');
       }
       var name = param.name;
       sb.write('$name: ');
       offset = sb.length;
       var defaultValue = _getDefaultValue(param);
       sb.write(defaultValue);
       ranges.addAll([offset, defaultValue.length]);
     }
   }

   suggestion.defaultArgumentListString = sb.isNotEmpty ? sb.toString() : null;
   suggestion.defaultArgumentListTextRanges = ranges.isNotEmpty ? ranges : null;
 }

 String buildClosureParameters(FunctionType type) {
   var buffer = StringBuffer();
   buffer.write('(');

   var hasNamed = false;
   var hasOptionalPositional = false;
   var parameters = type.parameters;
   for (var i = 0; i < parameters.length; ++i) {
     var parameter = parameters[i];
     if (i != 0) {
       buffer.write(', ');
     }
     if (parameter.isNamed && !hasNamed) {
       hasNamed = true;
       buffer.write('{');
     } else if (parameter.isOptionalPositional && !hasOptionalPositional) {
       hasOptionalPositional = true;
       buffer.write('[');
     }
     // todo (pq): consider abbreviating names
     buffer.write(parameter.name);
   }

   if (hasNamed) {
     buffer.write('}');
   } else if (hasOptionalPositional) {
     buffer.write(']');
   }

   buffer.write(')');
   return buffer.toString();
 }

 /// Create a new protocol Element for inclusion in a completion suggestion.
 protocol.Element createLocalElement(
     Source source, protocol.ElementKind kind, SimpleIdentifier id,
     {String parameters,
     TypeAnnotation returnType,
     bool isAbstract = false,
     bool isDeprecated = false}) {
   String name;
   Location location;
   if (id != null) {
     name = id.name;
     // TODO(danrubel) use lineInfo to determine startLine and startColumn
     location = Location(source.fullName, id.offset, id.length, 0, 0);
   } else {
     name = '';
     location = Location(source.fullName, -1, 0, 1, 0);
   }
   var flags = protocol.Element.makeFlags(
       isAbstract: isAbstract,
       isDeprecated: isDeprecated,
       isPrivate: Identifier.isPrivateName(name));
   return protocol.Element(kind, name, flags,
       location: location,
       parameters: parameters,
       returnType: nameForType(id, returnType));
 }

 /// Return a default argument value for the given [parameter].
 DefaultArgument getDefaultStringParameterValue(ParameterElement parameter,
     {@required bool withNullability}) {
   if (parameter != null) {
     var type = parameter.type;
     if (type is InterfaceType) {
       if (type.isDartCoreList) {
         return DefaultArgument('[]', cursorPosition: 1);
       } else if (type.isDartCoreMap) {
         return DefaultArgument('{}', cursorPosition: 1);
       } else if (type.isDartCoreString) {
         return DefaultArgument("''", cursorPosition: 1);
       }
     } else if (type is FunctionType) {
       var params = type.parameters
           .map((p) =>
               '${getTypeString(p.type, withNullability: withNullability)}${p.name}')
           .join(', ');
       // TODO(devoncarew): Support having this method return text with newlines.
       var text = '($params) {  }';
       return DefaultArgument(text, cursorPosition: text.length - 2);
     }
   }

   return null;
 }

 String getRequestLineIndent(DartCompletionRequest request) {
   var content = request.result.content;
   var lineStartOffset = request.offset;
   var notWhitespaceOffset = request.offset;
   for (; lineStartOffset > 0; lineStartOffset--) {
     var char = content.substring(lineStartOffset - 1, lineStartOffset);
     if (char == '\n') {
       break;
     }
     if (char != ' ' && char != '\t') {
       notWhitespaceOffset = lineStartOffset - 1;
     }
   }
   return content.substring(lineStartOffset, notWhitespaceOffset);
 }

 String getTypeString(DartType type, {@required bool withNullability}) {
   if (type.isDynamic) {
     return '';
   } else {
     return type.getDisplayString(withNullability: withNullability) + ' ';
   }
 }

 /// Return `true` if the @deprecated annotation is present on the given [node].
 bool isDeprecated(AnnotatedNode node) {
   if (node != null) {
     var metadata = node.metadata;
     if (metadata != null) {
       return metadata.any((Annotation a) {
         return a.name is SimpleIdentifier && a.name.name == 'deprecated';
       });
     }
   }
   return false;
 }

 /// Return name of the type of the given [identifier], or, if it unresolved, the
 /// name of its declared [declaredType].
 String nameForType(SimpleIdentifier identifier, TypeAnnotation declaredType) {
   if (identifier == null) {
     return null;
   }

   // Get the type from the identifier element.
   DartType type;
   var element = identifier.staticElement;
   if (element == null) {
     return DYNAMIC;
   } else if (element is FunctionTypedElement) {
     if (element is PropertyAccessorElement && element.isSetter) {
       return null;
     }
     type = element.returnType;
   } else if (element is FunctionTypeAliasElement) {
     type = element.function.returnType;
   } else if (element is VariableElement) {
     type = element.type;
   } else {
     return null;
   }

   // If the type is unresolved, use the declared type.
   if (type != null && type.isDynamic) {
     if (declaredType is TypeName) {
       var id = declaredType.name;
       if (id != null) {
         return id.name;
       }
     }
     return DYNAMIC;
   }

   if (type == null) {
     return DYNAMIC;
   }
   return type.getDisplayString(withNullability: false);
 }

 /// TODO(pq): fix to use getDefaultStringParameterValue()
 String _getDefaultValue(ParameterElement param) => 'null';

 /// A tuple of text to insert and an (optional) location for the cursor.
 class DefaultArgument {
   /// The text to insert.
   final String text;

   /// An optional location for the cursor, relative to the text's start. This
   /// field can be null.
   final int cursorPosition;

   DefaultArgument(this.text, {this.cursorPosition});
 }
	// 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.

	/// A collection of utility methods used by completion contributors.
	import 'package:analysis_server/src/protocol_server.dart'
	show CompletionSuggestion, Location;
	import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
	import 'package:analyzer/dart/ast/ast.dart';
	import 'package:analyzer/dart/ast/standard_ast_factory.dart';
	import 'package:analyzer/dart/ast/token.dart';
	import 'package:analyzer/dart/element/element.dart';
	import 'package:analyzer/dart/element/type.dart';
	import 'package:analyzer/src/dart/ast/token.dart';
	import 'package:analyzer/src/generated/source.dart';
	import 'package:analyzer_plugin/protocol/protocol_common.dart' as protocol
	show Element, ElementKind;
	import 'package:meta/meta.dart';

	/// The name of the type `dynamic`;
	const DYNAMIC = 'dynamic';

	/// Sort by relevance first, highest to lowest, and then by the completion
	/// alphabetically.
	Comparator<CompletionSuggestion> completionComparator = (a, b) {
	if (a.relevance == b.relevance) {
	return a.completion.compareTo(b.completion);
	}
	return b.relevance.compareTo(a.relevance);
	};

	/// A marker used in place of `null` when a function has no return type.
	final TypeName NO_RETURN_TYPE = astFactory.typeName(
	astFactory.simpleIdentifier(StringToken(TokenType.IDENTIFIER, '', 0)),
	null);

	/// 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) {
	var sb = StringBuffer();
	var ranges = <int>[];

	int offset;

	for (var param in requiredParams) {
	if (sb.isNotEmpty) {
	sb.write(', ');
	}
	offset = sb.length;

	if (param.type is FunctionType) {
	FunctionType type = param.type;

	var rangeStart = offset;
	int rangeLength;

	// todo (pq): consider adding ranges for params
	// pending: https://github.com/dart-lang/sdk/issues/40207
	// (types in closure param completions make this UX awkward)
	final parametersString = buildClosureParameters(type);
	final blockBuffer = StringBuffer(parametersString);

	blockBuffer.write(' ');

	// todo (pq): consider refactoring to share common logic w/
	// ArgListContributor.buildClosureSuggestions
	final returnType = type.returnType;
	if (returnType.isVoid) {
	blockBuffer.write('{');
	rangeStart = sb.length + blockBuffer.length;
	blockBuffer.write(' }');
	rangeLength = 1;
	} else {
	final returnValue = returnType.isDartCoreBool ? 'false' : 'null';
	blockBuffer.write('=> ');
	rangeStart = sb.length + blockBuffer.length;
	blockBuffer.write(returnValue);
	rangeLength = returnValue.length;
	}

	sb.write(blockBuffer);
	ranges.addAll([rangeStart, rangeLength]);
	} else {
	var name = param.name;
	sb.write(name);
	ranges.addAll([offset, name.length]);
	}
	}

	for (var param in namedParams) {
	if (param.hasRequired) {
	if (sb.isNotEmpty) {
	sb.write(', ');
	}
	var name = param.name;
	sb.write('$name: ');
	offset = sb.length;
	var defaultValue = _getDefaultValue(param);
	sb.write(defaultValue);
	ranges.addAll([offset, defaultValue.length]);
	}
	}

	suggestion.defaultArgumentListString = sb.isNotEmpty ? sb.toString() : null;
	suggestion.defaultArgumentListTextRanges = ranges.isNotEmpty ? ranges : null;
	}

	String buildClosureParameters(FunctionType type) {
	var buffer = StringBuffer();
	buffer.write('(');

	var hasNamed = false;
	var hasOptionalPositional = false;
	var parameters = type.parameters;
	for (var i = 0; i < parameters.length; ++i) {
	var parameter = parameters[i];
	if (i != 0) {
	buffer.write(', ');
	}
	if (parameter.isNamed && !hasNamed) {
	hasNamed = true;
	buffer.write('{');
	} else if (parameter.isOptionalPositional && !hasOptionalPositional) {
	hasOptionalPositional = true;
	buffer.write('[');
	}
	// todo (pq): consider abbreviating names
	buffer.write(parameter.name);
	}

	if (hasNamed) {
	buffer.write('}');
	} else if (hasOptionalPositional) {
	buffer.write(']');
	}

	buffer.write(')');
	return buffer.toString();
	}

	/// Create a new protocol Element for inclusion in a completion suggestion.
	protocol.Element createLocalElement(
	Source source, protocol.ElementKind kind, SimpleIdentifier id,
	{String parameters,
	TypeAnnotation returnType,
	bool isAbstract = false,
	bool isDeprecated = false}) {
	String name;
	Location location;
	if (id != null) {
	name = id.name;
	// TODO(danrubel) use lineInfo to determine startLine and startColumn
	location = Location(source.fullName, id.offset, id.length, 0, 0);
	} else {
	name = '';
	location = Location(source.fullName, -1, 0, 1, 0);
	}
	var flags = protocol.Element.makeFlags(
	isAbstract: isAbstract,
	isDeprecated: isDeprecated,
	isPrivate: Identifier.isPrivateName(name));
	return protocol.Element(kind, name, flags,
	location: location,
	parameters: parameters,
	returnType: nameForType(id, returnType));
	}

	/// Return a default argument value for the given [parameter].
	DefaultArgument getDefaultStringParameterValue(ParameterElement parameter,
	{@required bool withNullability}) {
	if (parameter != null) {
	var type = parameter.type;
	if (type is InterfaceType) {
	if (type.isDartCoreList) {
	return DefaultArgument('[]', cursorPosition: 1);
	} else if (type.isDartCoreMap) {
	return DefaultArgument('{}', cursorPosition: 1);
	} else if (type.isDartCoreString) {
	return DefaultArgument("''", cursorPosition: 1);
	}
	} else if (type is FunctionType) {
	var params = type.parameters
	.map((p) =>
	'${getTypeString(p.type, withNullability: withNullability)}${p.name}')
	.join(', ');
	// TODO(devoncarew): Support having this method return text with newlines.
	var text = '($params) { }';
	return DefaultArgument(text, cursorPosition: text.length - 2);
	}
	}

	return null;
	}

	String getRequestLineIndent(DartCompletionRequest request) {
	var content = request.result.content;
	var lineStartOffset = request.offset;
	var notWhitespaceOffset = request.offset;
	for (; lineStartOffset > 0; lineStartOffset--) {
	var char = content.substring(lineStartOffset - 1, lineStartOffset);
	if (char == '\n') {
	break;
	}
	if (char != ' ' && char != '\t') {
	notWhitespaceOffset = lineStartOffset - 1;
	}
	}
	return content.substring(lineStartOffset, notWhitespaceOffset);
	}

	String getTypeString(DartType type, {@required bool withNullability}) {
	if (type.isDynamic) {
	return '';
	} else {
	return type.getDisplayString(withNullability: withNullability) + ' ';
	}
	}

	/// Return `true` if the @deprecated annotation is present on the given [node].
	bool isDeprecated(AnnotatedNode node) {
	if (node != null) {
	var metadata = node.metadata;
	if (metadata != null) {
	return metadata.any((Annotation a) {
	return a.name is SimpleIdentifier && a.name.name == 'deprecated';
	});
	}
	}
	return false;
	}

	/// Return name of the type of the given [identifier], or, if it unresolved, the
	/// name of its declared [declaredType].
	String nameForType(SimpleIdentifier identifier, TypeAnnotation declaredType) {
	if (identifier == null) {
	return null;
	}

	// Get the type from the identifier element.
	DartType type;
	var element = identifier.staticElement;
	if (element == null) {
	return DYNAMIC;
	} else if (element is FunctionTypedElement) {
	if (element is PropertyAccessorElement && element.isSetter) {
	return null;
	}
	type = element.returnType;
	} else if (element is FunctionTypeAliasElement) {
	type = element.function.returnType;
	} else if (element is VariableElement) {
	type = element.type;
	} else {
	return null;
	}

	// If the type is unresolved, use the declared type.
	if (type != null && type.isDynamic) {
	if (declaredType is TypeName) {
	var id = declaredType.name;
	if (id != null) {
	return id.name;
	}
	}
	return DYNAMIC;
	}

	if (type == null) {
	return DYNAMIC;
	}
	return type.getDisplayString(withNullability: false);
	}

	/// TODO(pq): fix to use getDefaultStringParameterValue()
	String _getDefaultValue(ParameterElement param) => 'null';

	/// A tuple of text to insert and an (optional) location for the cursor.
	class DefaultArgument {
	/// The text to insert.
	final String text;

	/// An optional location for the cursor, relative to the text's start. This
	/// field can be null.
	final int cursorPosition;

	DefaultArgument(this.text, {this.cursorPosition});
	}