305 lines
12 KiB
TypeScript
305 lines
12 KiB
TypeScript
import * as ts from 'typescript';
|
|
import {Symbols} from './symbols';
|
|
|
|
function isMethodCallOf(callExpression: ts.CallExpression, memberName: string): boolean {
|
|
const expression = callExpression.expression;
|
|
if (expression.kind === ts.SyntaxKind.PropertyAccessExpression) {
|
|
const propertyAccessExpression = <ts.PropertyAccessExpression>expression;
|
|
const name = propertyAccessExpression.name;
|
|
if (name.kind == ts.SyntaxKind.Identifier) {
|
|
return name.text === memberName;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
function isCallOf(callExpression: ts.CallExpression, ident: string): boolean {
|
|
const expression = callExpression.expression;
|
|
if (expression.kind === ts.SyntaxKind.Identifier) {
|
|
const identifier = <ts.Identifier>expression;
|
|
return identifier.text === ident;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* ts.forEachChild stops iterating children when the callback return a truthy value.
|
|
* This method inverts this to implement an `every` style iterator. It will return
|
|
* true if every call to `cb` returns `true`.
|
|
*/
|
|
function everyNodeChild(node: ts.Node, cb: (node: ts.Node) => boolean) {
|
|
return !ts.forEachChild(node, node => !cb(node));
|
|
}
|
|
|
|
export interface SymbolReference {
|
|
__symbolic: string; // TODO: Change this to type "reference" when we move to TypeScript 1.8
|
|
name: string;
|
|
module: string;
|
|
}
|
|
|
|
function isPrimitive(value: any): boolean {
|
|
return Object(value) !== value;
|
|
}
|
|
|
|
function isDefined(obj: any): boolean {
|
|
return obj !== undefined;
|
|
}
|
|
|
|
/**
|
|
* Produce a symbolic representation of an expression folding values into their final value when
|
|
* possible.
|
|
*/
|
|
export class Evaluator {
|
|
constructor(private service: ts.LanguageService, private typeChecker: ts.TypeChecker,
|
|
private symbols: Symbols, private moduleNameOf: (fileName: string) => string) {}
|
|
|
|
// TODO: Determine if the first declaration is deterministic.
|
|
private symbolFileName(symbol: ts.Symbol): string {
|
|
if (symbol) {
|
|
if (symbol.flags & ts.SymbolFlags.Alias) {
|
|
symbol = this.typeChecker.getAliasedSymbol(symbol);
|
|
}
|
|
const declarations = symbol.getDeclarations();
|
|
if (declarations && declarations.length > 0) {
|
|
const sourceFile = declarations[0].getSourceFile();
|
|
if (sourceFile) {
|
|
return sourceFile.fileName;
|
|
}
|
|
}
|
|
}
|
|
return undefined;
|
|
}
|
|
|
|
private symbolReference(symbol: ts.Symbol): SymbolReference {
|
|
if (symbol) {
|
|
const name = symbol.name;
|
|
const module = this.moduleNameOf(this.symbolFileName(symbol));
|
|
return {__symbolic: "reference", name, module};
|
|
}
|
|
}
|
|
|
|
private nodeSymbolReference(node: ts.Node): SymbolReference {
|
|
return this.symbolReference(this.typeChecker.getSymbolAtLocation(node));
|
|
}
|
|
|
|
nameOf(node: ts.Node): string {
|
|
if (node.kind == ts.SyntaxKind.Identifier) {
|
|
return (<ts.Identifier>node).text;
|
|
}
|
|
return this.evaluateNode(node);
|
|
}
|
|
|
|
/**
|
|
* Returns true if the expression represented by `node` can be folded into a literal expression.
|
|
*
|
|
* For example, a literal is always foldable. This means that literal expressions such as `1.2`
|
|
* `"Some value"` `true` `false` are foldable.
|
|
*
|
|
* - An object literal is foldable if all the properties in the literal are foldable.
|
|
* - An array literal is foldable if all the elements are foldable.
|
|
* - A call is foldable if it is a call to a Array.prototype.concat or a call to CONST_EXPR.
|
|
* - A property access is foldable if the object is foldable.
|
|
* - A array index is foldable if index expression is foldable and the array is foldable.
|
|
* - Binary operator expressions are foldable if the left and right expressions are foldable and
|
|
* it is one of '+', '-', '*', '/', '%', '||', and '&&'.
|
|
* - An identifier is foldable if a value can be found for its symbol is in the evaluator symbol
|
|
* table.
|
|
*/
|
|
public isFoldable(node: ts.Node) {
|
|
if (node) {
|
|
switch (node.kind) {
|
|
case ts.SyntaxKind.ObjectLiteralExpression:
|
|
return everyNodeChild(node, child => {
|
|
if (child.kind === ts.SyntaxKind.PropertyAssignment) {
|
|
const propertyAssignment = <ts.PropertyAssignment>child;
|
|
return this.isFoldable(propertyAssignment.initializer)
|
|
}
|
|
return false;
|
|
});
|
|
case ts.SyntaxKind.ArrayLiteralExpression:
|
|
return everyNodeChild(node, child => this.isFoldable(child));
|
|
case ts.SyntaxKind.CallExpression:
|
|
const callExpression = <ts.CallExpression>node;
|
|
// We can fold a <array>.concat(<v>).
|
|
if (isMethodCallOf(callExpression, "concat") && callExpression.arguments.length === 1) {
|
|
const arrayNode = (<ts.PropertyAccessExpression>callExpression.expression).expression;
|
|
if (this.isFoldable(arrayNode) && this.isFoldable(callExpression.arguments[0])) {
|
|
// It needs to be an array.
|
|
const arrayValue = this.evaluateNode(arrayNode);
|
|
if (arrayValue && Array.isArray(arrayValue)) {
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
// We can fold a call to CONST_EXPR
|
|
if (isCallOf(callExpression, "CONST_EXPR") && callExpression.arguments.length === 1)
|
|
return this.isFoldable(callExpression.arguments[0]);
|
|
return false;
|
|
case ts.SyntaxKind.NoSubstitutionTemplateLiteral:
|
|
case ts.SyntaxKind.StringLiteral:
|
|
case ts.SyntaxKind.NumericLiteral:
|
|
case ts.SyntaxKind.NullKeyword:
|
|
case ts.SyntaxKind.TrueKeyword:
|
|
case ts.SyntaxKind.FalseKeyword:
|
|
return true;
|
|
case ts.SyntaxKind.BinaryExpression:
|
|
const binaryExpression = <ts.BinaryExpression>node;
|
|
switch (binaryExpression.operatorToken.kind) {
|
|
case ts.SyntaxKind.PlusToken:
|
|
case ts.SyntaxKind.MinusToken:
|
|
case ts.SyntaxKind.AsteriskToken:
|
|
case ts.SyntaxKind.SlashToken:
|
|
case ts.SyntaxKind.PercentToken:
|
|
case ts.SyntaxKind.AmpersandAmpersandToken:
|
|
case ts.SyntaxKind.BarBarToken:
|
|
return this.isFoldable(binaryExpression.left) &&
|
|
this.isFoldable(binaryExpression.right);
|
|
}
|
|
case ts.SyntaxKind.PropertyAccessExpression:
|
|
const propertyAccessExpression = <ts.PropertyAccessExpression>node;
|
|
return this.isFoldable(propertyAccessExpression.expression);
|
|
case ts.SyntaxKind.ElementAccessExpression:
|
|
const elementAccessExpression = <ts.ElementAccessExpression>node;
|
|
return this.isFoldable(elementAccessExpression.expression) &&
|
|
this.isFoldable(elementAccessExpression.argumentExpression);
|
|
case ts.SyntaxKind.Identifier:
|
|
const symbol = this.typeChecker.getSymbolAtLocation(node);
|
|
if (this.symbols.has(symbol)) return true;
|
|
break;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Produce a JSON serialiable object representing `node`. The foldable values in the expression
|
|
* tree are folded. For example, a node representing `1 + 2` is folded into `3`.
|
|
*/
|
|
public evaluateNode(node: ts.Node): any {
|
|
switch (node.kind) {
|
|
case ts.SyntaxKind.ObjectLiteralExpression:
|
|
let obj = {};
|
|
let allPropertiesDefined = true;
|
|
ts.forEachChild(node, child => {
|
|
switch (child.kind) {
|
|
case ts.SyntaxKind.PropertyAssignment:
|
|
const assignment = <ts.PropertyAssignment>child;
|
|
const propertyName = this.nameOf(assignment.name);
|
|
const propertyValue = this.evaluateNode(assignment.initializer);
|
|
obj[propertyName] = propertyValue;
|
|
allPropertiesDefined = isDefined(propertyValue) && allPropertiesDefined;
|
|
}
|
|
});
|
|
if (allPropertiesDefined) return obj;
|
|
break;
|
|
case ts.SyntaxKind.ArrayLiteralExpression:
|
|
let arr = [];
|
|
let allElementsDefined = true;
|
|
ts.forEachChild(node, child => {
|
|
const value = this.evaluateNode(child);
|
|
arr.push(value);
|
|
allElementsDefined = isDefined(value) && allElementsDefined;
|
|
});
|
|
if (allElementsDefined) return arr;
|
|
break;
|
|
case ts.SyntaxKind.CallExpression:
|
|
const callExpression = <ts.CallExpression>node;
|
|
const args = callExpression.arguments.map(arg => this.evaluateNode(arg));
|
|
if (this.isFoldable(callExpression)) {
|
|
if (isMethodCallOf(callExpression, "concat")) {
|
|
const arrayValue = this.evaluateNode(
|
|
(<ts.PropertyAccessExpression>callExpression.expression).expression);
|
|
return arrayValue.concat(args[0]);
|
|
}
|
|
}
|
|
// Always fold a CONST_EXPR even if the argument is not foldable.
|
|
if (isCallOf(callExpression, "CONST_EXPR") && callExpression.arguments.length === 1) {
|
|
return args[0];
|
|
}
|
|
const expression = this.evaluateNode(callExpression.expression);
|
|
if (isDefined(expression) && args.every(isDefined)) {
|
|
return {
|
|
__symbolic: "call",
|
|
expression: this.evaluateNode(callExpression.expression),
|
|
arguments: args
|
|
};
|
|
}
|
|
break;
|
|
case ts.SyntaxKind.PropertyAccessExpression: {
|
|
const propertyAccessExpression = <ts.PropertyAccessExpression>node;
|
|
const expression = this.evaluateNode(propertyAccessExpression.expression);
|
|
const member = this.nameOf(propertyAccessExpression.name);
|
|
if (this.isFoldable(propertyAccessExpression.expression)) return expression[member];
|
|
if (isDefined(expression)) {
|
|
return {__symbolic: "select", expression, member};
|
|
}
|
|
break;
|
|
}
|
|
case ts.SyntaxKind.ElementAccessExpression: {
|
|
const elementAccessExpression = <ts.ElementAccessExpression>node;
|
|
const expression = this.evaluateNode(elementAccessExpression.expression);
|
|
const index = this.evaluateNode(elementAccessExpression.argumentExpression);
|
|
if (this.isFoldable(elementAccessExpression.expression) &&
|
|
this.isFoldable(elementAccessExpression.argumentExpression))
|
|
return expression[index];
|
|
if (isDefined(expression) && isDefined(index)) {
|
|
return {
|
|
__symbolic: "index",
|
|
expression,
|
|
index: this.evaluateNode(elementAccessExpression.argumentExpression)
|
|
};
|
|
}
|
|
break;
|
|
}
|
|
case ts.SyntaxKind.Identifier:
|
|
const symbol = this.typeChecker.getSymbolAtLocation(node);
|
|
if (this.symbols.has(symbol)) return this.symbols.get(symbol);
|
|
return this.nodeSymbolReference(node);
|
|
case ts.SyntaxKind.NoSubstitutionTemplateLiteral:
|
|
return (<ts.LiteralExpression>node).text;
|
|
case ts.SyntaxKind.StringLiteral:
|
|
return (<ts.StringLiteral>node).text;
|
|
case ts.SyntaxKind.NumericLiteral:
|
|
return parseFloat((<ts.LiteralExpression>node).text);
|
|
case ts.SyntaxKind.NullKeyword:
|
|
return null;
|
|
case ts.SyntaxKind.TrueKeyword:
|
|
return true;
|
|
case ts.SyntaxKind.FalseKeyword:
|
|
return false;
|
|
|
|
case ts.SyntaxKind.BinaryExpression:
|
|
const binaryExpression = <ts.BinaryExpression>node;
|
|
const left = this.evaluateNode(binaryExpression.left);
|
|
const right = this.evaluateNode(binaryExpression.right);
|
|
if (isDefined(left) && isDefined(right)) {
|
|
if (isPrimitive(left) && isPrimitive(right))
|
|
switch (binaryExpression.operatorToken.kind) {
|
|
case ts.SyntaxKind.PlusToken:
|
|
return left + right;
|
|
case ts.SyntaxKind.MinusToken:
|
|
return left - right;
|
|
case ts.SyntaxKind.AsteriskToken:
|
|
return left * right;
|
|
case ts.SyntaxKind.SlashToken:
|
|
return left / right;
|
|
case ts.SyntaxKind.PercentToken:
|
|
return left % right;
|
|
case ts.SyntaxKind.AmpersandAmpersandToken:
|
|
return left && right;
|
|
case ts.SyntaxKind.BarBarToken:
|
|
return left || right;
|
|
}
|
|
return {
|
|
__symbolic: "binop",
|
|
operator: binaryExpression.operatorToken.getText(),
|
|
left: left,
|
|
right: right
|
|
};
|
|
}
|
|
break;
|
|
}
|
|
return undefined;
|
|
}
|
|
}
|