services.ts

/// <reference path="..\compiler\program.ts"/>
/// <reference path="..\compiler\commandLineParser.ts"/>

/// <reference path='types.ts' />
/// <reference path='utilities.ts' />
/// <reference path='breakpoints.ts' />
/// <reference path='classifier.ts' />
/// <reference path='completions.ts' />
/// <reference path='documentHighlights.ts' />
/// <reference path='documentRegistry.ts' />
/// <reference path='findAllReferences.ts' />
/// <reference path='goToDefinition.ts' />
/// <reference path='jsDoc.ts' />
/// <reference path='jsTyping.ts' />
/// <reference path='navigateTo.ts' />
/// <reference path='navigationBar.ts' />
/// <reference path='outliningElementsCollector.ts' />
/// <reference path='patternMatcher.ts' />
/// <reference path='preProcess.ts' />
/// <reference path='rename.ts' />
/// <reference path='signatureHelp.ts' />
/// <reference path='symbolDisplay.ts' />
/// <reference path='transpile.ts' />
/// <reference path='formatting\formatting.ts' />
/// <reference path='formatting\smartIndenter.ts' />
/// <reference path='textChanges.ts' />
/// <reference path='codeFixProvider.ts' />
/// <reference path='codefixes\fixes.ts' />

namespace ts {
    /** The version of the language service API */
    export const servicesVersion = "0.5";

    /* @internal */
    let ruleProvider: formatting.RulesProvider;

    function createNode<TKind extends SyntaxKind>(kind: TKind, pos: number, end: number, parent?: Node): NodeObject | TokenObject<TKind> | IdentifierObject {
        const node = kind >= SyntaxKind.FirstNode ? new NodeObject(kind, pos, end) :
            kind === SyntaxKind.Identifier ? new IdentifierObject(SyntaxKind.Identifier, pos, end) :
                new TokenObject(kind, pos, end);
        node.parent = parent;
        return node;
    }

    class NodeObject implements Node {
        public kind: SyntaxKind;
        public pos: number;
        public end: number;
        public flags: NodeFlags;
        public parent: Node;
        public jsDoc: JSDoc[];
        public original: Node;
        public transformFlags: TransformFlags;
        private _children: Node[];

        constructor(kind: SyntaxKind, pos: number, end: number) {
            this.pos = pos;
            this.end = end;
            this.flags = NodeFlags.None;
            this.transformFlags = undefined;
            this.parent = undefined;
            this.kind = kind;
        }

        public getSourceFile(): SourceFile {
            return getSourceFileOfNode(this);
        }

        public getStart(sourceFile?: SourceFileLike, includeJsDocComment?: boolean): number {
            return getTokenPosOfNode(this, sourceFile, includeJsDocComment);
        }

        public getFullStart(): number {
            return this.pos;
        }

        public getEnd(): number {
            return this.end;
        }

        public getWidth(sourceFile?: SourceFile): number {
            return this.getEnd() - this.getStart(sourceFile);
        }

        public getFullWidth(): number {
            return this.end - this.pos;
        }

        public getLeadingTriviaWidth(sourceFile?: SourceFile): number {
            return this.getStart(sourceFile) - this.pos;
        }

        public getFullText(sourceFile?: SourceFile): string {
            return (sourceFile || this.getSourceFile()).text.substring(this.pos, this.end);
        }

        public getText(sourceFile?: SourceFile): string {
            if (!sourceFile) {
                sourceFile = this.getSourceFile();
            }
            return sourceFile.text.substring(this.getStart(sourceFile), this.getEnd());
        }

        private addSyntheticNodes(nodes: Node[], pos: number, end: number, useJSDocScanner?: boolean): number {
            scanner.setTextPos(pos);
            while (pos < end) {
                const token = useJSDocScanner ? scanner.scanJSDocToken() : scanner.scan();
                const textPos = scanner.getTextPos();
                if (textPos <= end) {
                    nodes.push(createNode(token, pos, textPos, this));
                }
                pos = textPos;
            }
            return pos;
        }

        private createSyntaxList(nodes: NodeArray<Node>): Node {
            const list = <NodeObject>createNode(SyntaxKind.SyntaxList, nodes.pos, nodes.end, this);
            list._children = [];
            let pos = nodes.pos;

            for (const node of nodes) {
                if (pos < node.pos) {
                    pos = this.addSyntheticNodes(list._children, pos, node.pos);
                }
                list._children.push(node);
                pos = node.end;
            }
            if (pos < nodes.end) {
                this.addSyntheticNodes(list._children, pos, nodes.end);
            }
            return list;
        }

        private createChildren(sourceFile?: SourceFileLike) {
            let children: Node[];
            if (this.kind >= SyntaxKind.FirstNode) {
                scanner.setText((sourceFile || this.getSourceFile()).text);
                children = [];
                let pos = this.pos;
                const useJSDocScanner = this.kind >= SyntaxKind.FirstJSDocTagNode && this.kind <= SyntaxKind.LastJSDocTagNode;
                const processNode = (node: Node) => {
                    const isJSDocTagNode = isJSDocTag(node);
                    if (!isJSDocTagNode && pos < node.pos) {
                        pos = this.addSyntheticNodes(children, pos, node.pos, useJSDocScanner);
                    }
                    children.push(node);
                    if (!isJSDocTagNode) {
                        pos = node.end;
                    }
                };
                const processNodes = (nodes: NodeArray<Node>) => {
                    if (pos < nodes.pos) {
                        pos = this.addSyntheticNodes(children, pos, nodes.pos, useJSDocScanner);
                    }
                    children.push(this.createSyntaxList(<NodeArray<Node>>nodes));
                    pos = nodes.end;
                };
                // jsDocComments need to be the first children
                if (this.jsDoc) {
                    for (const jsDocComment of this.jsDoc) {
                        processNode(jsDocComment);
                    }
                }
                // For syntactic classifications, all trivia are classcified together, including jsdoc comments.
                // For that to work, the jsdoc comments should still be the leading trivia of the first child.
                // Restoring the scanner position ensures that.
                pos = this.pos;
                forEachChild(this, processNode, processNodes);
                if (pos < this.end) {
                    this.addSyntheticNodes(children, pos, this.end);
                }
                scanner.setText(undefined);
            }
            this._children = children || emptyArray;
        }

        public getChildCount(sourceFile?: SourceFile): number {
            if (!this._children) this.createChildren(sourceFile);
            return this._children.length;
        }

        public getChildAt(index: number, sourceFile?: SourceFile): Node {
            if (!this._children) this.createChildren(sourceFile);
            return this._children[index];
        }

        public getChildren(sourceFile?: SourceFileLike): Node[] {
            if (!this._children) this.createChildren(sourceFile);
            return this._children;
        }

        public getFirstToken(sourceFile?: SourceFile): Node {
            const children = this.getChildren(sourceFile);
            if (!children.length) {
                return undefined;
            }

            const child = ts.find(children, kid => kid.kind < SyntaxKind.FirstJSDocNode || kid.kind > SyntaxKind.LastJSDocNode);
            return child.kind < SyntaxKind.FirstNode ?
                child :
                child.getFirstToken(sourceFile);
        }

        public getLastToken(sourceFile?: SourceFile): Node {
            const children = this.getChildren(sourceFile);

            const child = lastOrUndefined(children);
            if (!child) {
                return undefined;
            }

            return child.kind < SyntaxKind.FirstNode ? child : child.getLastToken(sourceFile);
        }

        public forEachChild<T>(cbNode: (node: Node) => T, cbNodeArray?: (nodes: Node[]) => T): T {
            return forEachChild(this, cbNode, cbNodeArray);
        }
    }

    class TokenOrIdentifierObject implements Node {
        public kind: SyntaxKind;
        public pos: number;
        public end: number;
        public flags: NodeFlags;
        public parent: Node;
        public jsDocComments: JSDoc[];

        constructor(pos: number, end: number) {
            // Set properties in same order as NodeObject
            this.pos = pos;
            this.end = end;
            this.flags = NodeFlags.None;
            this.parent = undefined;
        }

        public getSourceFile(): SourceFile {
            return getSourceFileOfNode(this);
        }

        public getStart(sourceFile?: SourceFileLike, includeJsDocComment?: boolean): number {
            return getTokenPosOfNode(this, sourceFile, includeJsDocComment);
        }

        public getFullStart(): number {
            return this.pos;
        }

        public getEnd(): number {
            return this.end;
        }

        public getWidth(sourceFile?: SourceFile): number {
            return this.getEnd() - this.getStart(sourceFile);
        }

        public getFullWidth(): number {
            return this.end - this.pos;
        }

        public getLeadingTriviaWidth(sourceFile?: SourceFile): number {
            return this.getStart(sourceFile) - this.pos;
        }

        public getFullText(sourceFile?: SourceFile): string {
            return (sourceFile || this.getSourceFile()).text.substring(this.pos, this.end);
        }

        public getText(sourceFile?: SourceFile): string {
            return (sourceFile || this.getSourceFile()).text.substring(this.getStart(), this.getEnd());
        }

        public getChildCount(): number {
            return 0;
        }

        public getChildAt(): Node {
            return undefined;
        }

        public getChildren(): Node[] {
            return emptyArray;
        }

        public getFirstToken(): Node {
            return undefined;
        }

        public getLastToken(): Node {
            return undefined;
        }

        public forEachChild<T>(): T {
            return undefined;
        }
    }

    class SymbolObject implements Symbol {
        flags: SymbolFlags;
        name: string;
        declarations: Declaration[];

        // Undefined is used to indicate the value has not been computed. If, after computing, the
        // symbol has no doc comment, then the empty string will be returned.
        documentationComment: SymbolDisplayPart[];

        // Undefined is used to indicate the value has not been computed. If, after computing, the
        // symbol has no JSDoc tags, then the empty array will be returned.
        tags: JSDocTagInfo[];

        constructor(flags: SymbolFlags, name: string) {
            this.flags = flags;
            this.name = name;
        }

        getFlags(): SymbolFlags {
            return this.flags;
        }

        getName(): string {
            return this.name;
        }

        getDeclarations(): Declaration[] {
            return this.declarations;
        }

        getDocumentationComment(): SymbolDisplayPart[] {
            if (this.documentationComment === undefined) {
                this.documentationComment = JsDoc.getJsDocCommentsFromDeclarations(this.declarations);
            }

            return this.documentationComment;
        }

        getJsDocTags(): JSDocTagInfo[] {
            if (this.tags === undefined) {
                this.tags = JsDoc.getJsDocTagsFromDeclarations(this.declarations);
            }

            return this.tags;
        }
    }

    class TokenObject<TKind extends SyntaxKind> extends TokenOrIdentifierObject implements Token<TKind> {
        public kind: TKind;

        constructor(kind: TKind, pos: number, end: number) {
            super(pos, end);
            this.kind = kind;
        }
    }

    class IdentifierObject extends TokenOrIdentifierObject implements Identifier {
        public kind: SyntaxKind.Identifier;
        public text: string;
        _primaryExpressionBrand: any;
        _memberExpressionBrand: any;
        _leftHandSideExpressionBrand: any;
        _incrementExpressionBrand: any;
        _unaryExpressionBrand: any;
        _expressionBrand: any;
        constructor(_kind: SyntaxKind.Identifier, pos: number, end: number) {
            super(pos, end);
        }
    }
    IdentifierObject.prototype.kind = SyntaxKind.Identifier;

    class TypeObject implements Type {
        checker: TypeChecker;
        flags: TypeFlags;
        objectFlags?: ObjectFlags;
        id: number;
        symbol: Symbol;
        constructor(checker: TypeChecker, flags: TypeFlags) {
            this.checker = checker;
            this.flags = flags;
        }
        getFlags(): TypeFlags {
            return this.flags;
        }
        getSymbol(): Symbol {
            return this.symbol;
        }
        getProperties(): Symbol[] {
            return this.checker.getPropertiesOfType(this);
        }
        getProperty(propertyName: string): Symbol {
            return this.checker.getPropertyOfType(this, propertyName);
        }
        getApparentProperties(): Symbol[] {
            return this.checker.getAugmentedPropertiesOfType(this);
        }
        getCallSignatures(): Signature[] {
            return this.checker.getSignaturesOfType(this, SignatureKind.Call);
        }
        getConstructSignatures(): Signature[] {
            return this.checker.getSignaturesOfType(this, SignatureKind.Construct);
        }
        getStringIndexType(): Type {
            return this.checker.getIndexTypeOfType(this, IndexKind.String);
        }
        getNumberIndexType(): Type {
            return this.checker.getIndexTypeOfType(this, IndexKind.Number);
        }
        getBaseTypes(): BaseType[] {
            return this.flags & TypeFlags.Object && this.objectFlags & (ObjectFlags.Class | ObjectFlags.Interface)
                ? this.checker.getBaseTypes(<InterfaceType><Type>this)
                : undefined;
        }
        getNonNullableType(): Type {
            return this.checker.getNonNullableType(this);
        }
    }

    class SignatureObject implements Signature {
        checker: TypeChecker;
        declaration: SignatureDeclaration;
        typeParameters: TypeParameter[];
        parameters: Symbol[];
        thisParameter: Symbol;
        resolvedReturnType: Type;
        minTypeArgumentCount: number;
        minArgumentCount: number;
        hasRestParameter: boolean;
        hasLiteralTypes: boolean;

        // Undefined is used to indicate the value has not been computed. If, after computing, the
        // symbol has no doc comment, then the empty string will be returned.
        documentationComment: SymbolDisplayPart[];

        // Undefined is used to indicate the value has not been computed. If, after computing, the
        // symbol has no doc comment, then the empty array will be returned.
        jsDocTags: JSDocTagInfo[];

        constructor(checker: TypeChecker) {
            this.checker = checker;
        }
        getDeclaration(): SignatureDeclaration {
            return this.declaration;
        }
        getTypeParameters(): TypeParameter[] {
            return this.typeParameters;
        }
        getParameters(): Symbol[] {
            return this.parameters;
        }
        getReturnType(): Type {
            return this.checker.getReturnTypeOfSignature(this);
        }

        getDocumentationComment(): SymbolDisplayPart[] {
            if (this.documentationComment === undefined) {
                this.documentationComment = this.declaration ? JsDoc.getJsDocCommentsFromDeclarations([this.declaration]) : [];
            }

            return this.documentationComment;
        }

        getJsDocTags(): JSDocTagInfo[] {
            if (this.jsDocTags === undefined) {
                this.jsDocTags = this.declaration ? JsDoc.getJsDocTagsFromDeclarations([this.declaration]) : [];
            }

            return this.jsDocTags;
        }
    }

    class SourceFileObject extends NodeObject implements SourceFile {
        public kind: SyntaxKind.SourceFile;
        public _declarationBrand: any;
        public fileName: string;
        public path: Path;
        public text: string;
        public scriptSnapshot: IScriptSnapshot;
        public lineMap: number[];

        public statements: NodeArray<Statement>;
        public endOfFileToken: Token<SyntaxKind.EndOfFileToken>;

        public amdDependencies: { name: string; path: string }[];
        public moduleName: string;
        public referencedFiles: FileReference[];
        public typeReferenceDirectives: FileReference[];

        public syntacticDiagnostics: Diagnostic[];
        public referenceDiagnostics: Diagnostic[];
        public parseDiagnostics: Diagnostic[];
        public bindDiagnostics: Diagnostic[];

        public isDeclarationFile: boolean;
        public isDefaultLib: boolean;
        public hasNoDefaultLib: boolean;
        public externalModuleIndicator: Node; // The first node that causes this file to be an external module
        public commonJsModuleIndicator: Node; // The first node that causes this file to be a CommonJS module
        public nodeCount: number;
        public identifierCount: number;
        public symbolCount: number;
        public version: string;
        public scriptKind: ScriptKind;
        public languageVersion: ScriptTarget;
        public languageVariant: LanguageVariant;
        public identifiers: Map<string>;
        public nameTable: Map<number>;
        public resolvedModules: Map<ResolvedModuleFull>;
        public resolvedTypeReferenceDirectiveNames: Map<ResolvedTypeReferenceDirective>;
        public imports: StringLiteral[];
        public moduleAugmentations: StringLiteral[];
        private namedDeclarations: Map<Declaration[]>;
        public ambientModuleNames: string[];
        public checkJsDirective: CheckJsDirective | undefined;

        constructor(kind: SyntaxKind, pos: number, end: number) {
            super(kind, pos, end);
        }

        public update(newText: string, textChangeRange: TextChangeRange): SourceFile {
            return updateSourceFile(this, newText, textChangeRange);
        }

        public getLineAndCharacterOfPosition(position: number): LineAndCharacter {
            return ts.getLineAndCharacterOfPosition(this, position);
        }

        public getLineStarts(): number[] {
            return getLineStarts(this);
        }

        public getPositionOfLineAndCharacter(line: number, character: number): number {
            return ts.getPositionOfLineAndCharacter(this, line, character);
        }

        public getLineEndOfPosition(pos: number): number {
            const { line } = this.getLineAndCharacterOfPosition(pos);
            const lineStarts = this.getLineStarts();

            let lastCharPos: number;
            if (line + 1 >= lineStarts.length) {
                lastCharPos = this.getEnd();
            }
            if (!lastCharPos) {
                lastCharPos = lineStarts[line + 1] - 1;
            }

            const fullText = this.getFullText();
            // if the new line is "\r\n", we should return the last non-new-line-character position
            return fullText[lastCharPos] === "\n" && fullText[lastCharPos - 1] === "\r" ? lastCharPos - 1 : lastCharPos;
        }

        public getNamedDeclarations(): Map<Declaration[]> {
            if (!this.namedDeclarations) {
                this.namedDeclarations = this.computeNamedDeclarations();
            }

            return this.namedDeclarations;
        }

        private computeNamedDeclarations(): Map<Declaration[]> {
            const result = createMultiMap<Declaration>();

            forEachChild(this, visit);

            return result;

            function addDeclaration(declaration: Declaration) {
                const name = getDeclarationName(declaration);
                if (name) {
                    result.add(name, declaration);
                }
            }

            function getDeclarations(name: string) {
                let declarations = result.get(name);
                if (!declarations) {
                    result.set(name, declarations = []);
                }
                return declarations;
            }

            function getDeclarationName(declaration: Declaration) {
                if (declaration.name) {
                    const result = getTextOfIdentifierOrLiteral(declaration.name);
                    if (result !== undefined) {
                        return result;
                    }

                    if (declaration.name.kind === SyntaxKind.ComputedPropertyName) {
                        const expr = (<ComputedPropertyName>declaration.name).expression;
                        if (expr.kind === SyntaxKind.PropertyAccessExpression) {
                            return (<PropertyAccessExpression>expr).name.text;
                        }

                        return getTextOfIdentifierOrLiteral(expr);
                    }
                }

                return undefined;
            }

            function getTextOfIdentifierOrLiteral(node: Node) {
                if (node) {
                    if (node.kind === SyntaxKind.Identifier ||
                        node.kind === SyntaxKind.StringLiteral ||
                        node.kind === SyntaxKind.NumericLiteral) {

                        return (<Identifier | LiteralExpression>node).text;
                    }
                }

                return undefined;
            }

            function visit(node: Node): void {
                switch (node.kind) {
                    case SyntaxKind.FunctionDeclaration:
                    case SyntaxKind.FunctionExpression:
                    case SyntaxKind.MethodDeclaration:
                    case SyntaxKind.MethodSignature:
                        const functionDeclaration = <FunctionLikeDeclaration>node;
                        const declarationName = getDeclarationName(functionDeclaration);

                        if (declarationName) {
                            const declarations = getDeclarations(declarationName);
                            const lastDeclaration = lastOrUndefined(declarations);

                            // Check whether this declaration belongs to an "overload group".
                            if (lastDeclaration && functionDeclaration.parent === lastDeclaration.parent && functionDeclaration.symbol === lastDeclaration.symbol) {
                                // Overwrite the last declaration if it was an overload
                                // and this one is an implementation.
                                if (functionDeclaration.body && !(<FunctionLikeDeclaration>lastDeclaration).body) {
                                    declarations[declarations.length - 1] = functionDeclaration;
                                }
                            }
                            else {
                                declarations.push(functionDeclaration);
                            }
                        }
                        forEachChild(node, visit);
                        break;

                    case SyntaxKind.ClassDeclaration:
                    case SyntaxKind.ClassExpression:
                    case SyntaxKind.InterfaceDeclaration:
                    case SyntaxKind.TypeAliasDeclaration:
                    case SyntaxKind.EnumDeclaration:
                    case SyntaxKind.ModuleDeclaration:
                    case SyntaxKind.ImportEqualsDeclaration:
                    case SyntaxKind.ExportSpecifier:
                    case SyntaxKind.ImportSpecifier:
                    case SyntaxKind.ImportEqualsDeclaration:
                    case SyntaxKind.ImportClause:
                    case SyntaxKind.NamespaceImport:
                    case SyntaxKind.GetAccessor:
                    case SyntaxKind.SetAccessor:
                    case SyntaxKind.TypeLiteral:
                        addDeclaration(<Declaration>node);
                        forEachChild(node, visit);
                        break;

                    case SyntaxKind.Parameter:
                        // Only consider parameter properties
                        if (!hasModifier(node, ModifierFlags.ParameterPropertyModifier)) {
                            break;
                        }
                        // falls through
                    case SyntaxKind.VariableDeclaration:
                    case SyntaxKind.BindingElement: {
                        const decl = <VariableDeclaration>node;
                        if (isBindingPattern(decl.name)) {
                            forEachChild(decl.name, visit);
                            break;
                        }
                        if (decl.initializer)
                            visit(decl.initializer);
                    }
                        // falls through
                    case SyntaxKind.EnumMember:
                    case SyntaxKind.PropertyDeclaration:
                    case SyntaxKind.PropertySignature:
                        addDeclaration(<Declaration>node);
                        break;

                    case SyntaxKind.ExportDeclaration:
                        // Handle named exports case e.g.:
                        //    export {a, b as B} from "mod";
                        if ((<ExportDeclaration>node).exportClause) {
                            forEach((<ExportDeclaration>node).exportClause.elements, visit);
                        }
                        break;

                    case SyntaxKind.ImportDeclaration:
                        const importClause = (<ImportDeclaration>node).importClause;
                        if (importClause) {
                            // Handle default import case e.g.:
                            //    import d from "mod";
                            if (importClause.name) {
                                addDeclaration(importClause);
                            }

                            // Handle named bindings in imports e.g.:
                            //    import * as NS from "mod";
                            //    import {a, b as B} from "mod";
                            if (importClause.namedBindings) {
                                if (importClause.namedBindings.kind === SyntaxKind.NamespaceImport) {
                                    addDeclaration(<NamespaceImport>importClause.namedBindings);
                                }
                                else {
                                    forEach((<NamedImports>importClause.namedBindings).elements, visit);
                                }
                            }
                        }
                        break;

                    default:
                        forEachChild(node, visit);
                }
            }
        }
    }

    function getServicesObjectAllocator(): ObjectAllocator {
        return {
            getNodeConstructor: () => NodeObject,
            getTokenConstructor: () => TokenObject,

            getIdentifierConstructor: () => IdentifierObject,
            getSourceFileConstructor: () => SourceFileObject,
            getSymbolConstructor: () => SymbolObject,
            getTypeConstructor: () => TypeObject,
            getSignatureConstructor: () => SignatureObject,
        };
    }

    /// Language Service

    // Information about a specific host file.
    interface HostFileInformation {
        hostFileName: string;
        version: string;
        scriptSnapshot: IScriptSnapshot;
        scriptKind: ScriptKind;
    }

    export interface DisplayPartsSymbolWriter extends SymbolWriter {
        displayParts(): SymbolDisplayPart[];
    }

    /* @internal */
    export function toEditorSettings(options: FormatCodeOptions | FormatCodeSettings): FormatCodeSettings;
    export function toEditorSettings(options: EditorOptions | EditorSettings): EditorSettings;
    export function toEditorSettings(optionsAsMap: MapLike<any>): MapLike<any> {
        let allPropertiesAreCamelCased = true;
        for (const key in optionsAsMap) {
            if (hasProperty(optionsAsMap, key) && !isCamelCase(key)) {
                allPropertiesAreCamelCased = false;
                break;
            }
        }
        if (allPropertiesAreCamelCased) {
            return optionsAsMap;
        }
        const settings: MapLike<any> = {};
        for (const key in optionsAsMap) {
            if (hasProperty(optionsAsMap, key)) {
                const newKey = isCamelCase(key) ? key : key.charAt(0).toLowerCase() + key.substr(1);
                settings[newKey] = optionsAsMap[key];
            }
        }
        return settings;
    }

    function isCamelCase(s: string) {
        return !s.length || s.charAt(0) === s.charAt(0).toLowerCase();
    }

    export function displayPartsToString(displayParts: SymbolDisplayPart[]) {
        if (displayParts) {
            return map(displayParts, displayPart => displayPart.text).join("");
        }

        return "";
    }

    export function getDefaultCompilerOptions(): CompilerOptions {
        // Always default to "ScriptTarget.ES5" for the language service
        return {
            target: ScriptTarget.ES5,
            jsx: JsxEmit.Preserve
        };
    }

    export function getSupportedCodeFixes() {
        return codefix.getSupportedErrorCodes();
    }

    // Cache host information about script Should be refreshed
    // at each language service public entry point, since we don't know when
    // the set of scripts handled by the host changes.
    class HostCache {
        private fileNameToEntry: FileMap<HostFileInformation>;
        private _compilationSettings: CompilerOptions;
        private currentDirectory: string;

        constructor(private host: LanguageServiceHost, private getCanonicalFileName: (fileName: string) => string) {
            // script id => script index
            this.currentDirectory = host.getCurrentDirectory();
            this.fileNameToEntry = createFileMap<HostFileInformation>();

            // Initialize the list with the root file names
            const rootFileNames = host.getScriptFileNames();
            for (const fileName of rootFileNames) {
                this.createEntry(fileName, toPath(fileName, this.currentDirectory, getCanonicalFileName));
            }

            // store the compilation settings
            this._compilationSettings = host.getCompilationSettings() || getDefaultCompilerOptions();
        }

        public compilationSettings() {
            return this._compilationSettings;
        }

        private createEntry(fileName: string, path: Path) {
            let entry: HostFileInformation;
            const scriptSnapshot = this.host.getScriptSnapshot(fileName);
            if (scriptSnapshot) {
                entry = {
                    hostFileName: fileName,
                    version: this.host.getScriptVersion(fileName),
                    scriptSnapshot: scriptSnapshot,
                    scriptKind: getScriptKind(fileName, this.host)
                };
            }

            this.fileNameToEntry.set(path, entry);
            return entry;
        }

        private getEntry(path: Path): HostFileInformation {
            return this.fileNameToEntry.get(path);
        }

        private contains(path: Path): boolean {
            return this.fileNameToEntry.contains(path);
        }

        public getOrCreateEntry(fileName: string): HostFileInformation {
            const path = toPath(fileName, this.currentDirectory, this.getCanonicalFileName);
            return this.getOrCreateEntryByPath(fileName, path);
        }

        public getOrCreateEntryByPath(fileName: string, path: Path): HostFileInformation {
            return this.contains(path)
                ? this.getEntry(path)
                : this.createEntry(fileName, path);
        }

        public getRootFileNames(): string[] {
            const fileNames: string[] = [];

            this.fileNameToEntry.forEachValue((_path, value) => {
                if (value) {
                    fileNames.push(value.hostFileName);
                }
            });

            return fileNames;
        }

        public getVersion(path: Path): string {
            const file = this.getEntry(path);
            return file && file.version;
        }

        public getScriptSnapshot(path: Path): IScriptSnapshot {
            const file = this.getEntry(path);
            return file && file.scriptSnapshot;
        }
    }

    class SyntaxTreeCache {
        // For our syntactic only features, we also keep a cache of the syntax tree for the
        // currently edited file.
        private currentFileName: string;
        private currentFileVersion: string;
        private currentFileScriptSnapshot: IScriptSnapshot;
        private currentSourceFile: SourceFile;

        constructor(private host: LanguageServiceHost) {
        }

        public getCurrentSourceFile(fileName: string): SourceFile {
            const scriptSnapshot = this.host.getScriptSnapshot(fileName);
            if (!scriptSnapshot) {
                // The host does not know about this file.
                throw new Error("Could not find file: '" + fileName + "'.");
            }

            const scriptKind = getScriptKind(fileName, this.host);
            const version = this.host.getScriptVersion(fileName);
            let sourceFile: SourceFile;

            if (this.currentFileName !== fileName) {
                // This is a new file, just parse it
                sourceFile = createLanguageServiceSourceFile(fileName, scriptSnapshot, ScriptTarget.Latest, version, /*setNodeParents*/ true, scriptKind);
            }
            else if (this.currentFileVersion !== version) {
                // This is the same file, just a newer version. Incrementally parse the file.
                const editRange = scriptSnapshot.getChangeRange(this.currentFileScriptSnapshot);
                sourceFile = updateLanguageServiceSourceFile(this.currentSourceFile, scriptSnapshot, version, editRange);
            }

            if (sourceFile) {
                // All done, ensure state is up to date
                this.currentFileVersion = version;
                this.currentFileName = fileName;
                this.currentFileScriptSnapshot = scriptSnapshot;
                this.currentSourceFile = sourceFile;
            }

            return this.currentSourceFile;
        }
    }

    function setSourceFileFields(sourceFile: SourceFile, scriptSnapshot: IScriptSnapshot, version: string) {
        sourceFile.version = version;
        sourceFile.scriptSnapshot = scriptSnapshot;
    }

    export function createLanguageServiceSourceFile(fileName: string, scriptSnapshot: IScriptSnapshot, scriptTarget: ScriptTarget, version: string, setNodeParents: boolean, scriptKind?: ScriptKind): SourceFile {
        const text = scriptSnapshot.getText(0, scriptSnapshot.getLength());
        const sourceFile = createSourceFile(fileName, text, scriptTarget, setNodeParents, scriptKind);
        setSourceFileFields(sourceFile, scriptSnapshot, version);
        return sourceFile;
    }

    export let disableIncrementalParsing = false;

    export function updateLanguageServiceSourceFile(sourceFile: SourceFile, scriptSnapshot: IScriptSnapshot, version: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile {
        // If we were given a text change range, and our version or open-ness changed, then
        // incrementally parse this file.
        if (textChangeRange) {
            if (version !== sourceFile.version) {
                // Once incremental parsing is ready, then just call into this function.
                if (!disableIncrementalParsing) {
                    let newText: string;

                    // grab the fragment from the beginning of the original text to the beginning of the span
                    const prefix = textChangeRange.span.start !== 0
                        ? sourceFile.text.substr(0, textChangeRange.span.start)
                        : "";

                    // grab the fragment from the end of the span till the end of the original text
                    const suffix = textSpanEnd(textChangeRange.span) !== sourceFile.text.length
                        ? sourceFile.text.substr(textSpanEnd(textChangeRange.span))
                        : "";

                    if (textChangeRange.newLength === 0) {
                        // edit was a deletion - just combine prefix and suffix
                        newText = prefix && suffix ? prefix + suffix : prefix || suffix;
                    }
                    else {
                        // it was actual edit, fetch the fragment of new text that correspond to new span
                        const changedText = scriptSnapshot.getText(textChangeRange.span.start, textChangeRange.span.start + textChangeRange.newLength);
                        // combine prefix, changed text and suffix
                        newText = prefix && suffix
                            ? prefix + changedText + suffix
                            : prefix
                                ? (prefix + changedText)
                                : (changedText + suffix);
                    }

                    const newSourceFile = updateSourceFile(sourceFile, newText, textChangeRange, aggressiveChecks);
                    setSourceFileFields(newSourceFile, scriptSnapshot, version);
                    // after incremental parsing nameTable might not be up-to-date
                    // drop it so it can be lazily recreated later
                    newSourceFile.nameTable = undefined;

                    // dispose all resources held by old script snapshot
                    if (sourceFile !== newSourceFile && sourceFile.scriptSnapshot) {
                        if (sourceFile.scriptSnapshot.dispose) {
                            sourceFile.scriptSnapshot.dispose();
                        }

                        sourceFile.scriptSnapshot = undefined;
                    }

                    return newSourceFile;
                }
            }
        }

        // Otherwise, just create a new source file.
        return createLanguageServiceSourceFile(sourceFile.fileName, scriptSnapshot, sourceFile.languageVersion, version, /*setNodeParents*/ true, sourceFile.scriptKind);
    }

    class CancellationTokenObject implements CancellationToken {
        constructor(private cancellationToken: HostCancellationToken) {
        }