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fix(compiler): Fixed ?. operator to short-circut execution (#9965)

Fixes: #9850
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chuckjaz committed Jul 11, 2016
1 parent e6b2443 commit 4ec2a3094281fd859a89e06e5ce50daacac16790
@@ -28,15 +28,15 @@ export class ExpressionWithWrappedValueInfo {
export function convertCdExpressionToIr(
nameResolver: NameResolver, implicitReceiver: o.Expression, expression: cdAst.AST,
valueUnwrapper: o.ReadVarExpr): ExpressionWithWrappedValueInfo {
var visitor = new _AstToIrVisitor(nameResolver, implicitReceiver, valueUnwrapper);
var irAst: o.Expression = expression.visit(visitor, _Mode.Expression);
const visitor = new _AstToIrVisitor(nameResolver, implicitReceiver, valueUnwrapper);
const irAst: o.Expression = expression.visit(visitor, _Mode.Expression);
return new ExpressionWithWrappedValueInfo(irAst, visitor.needsValueUnwrapper);
}
export function convertCdStatementToIr(
nameResolver: NameResolver, implicitReceiver: o.Expression, stmt: cdAst.AST): o.Statement[] {
var visitor = new _AstToIrVisitor(nameResolver, implicitReceiver, null);
var statements: any[] /** TODO #9100 */ = [];
const visitor = new _AstToIrVisitor(nameResolver, implicitReceiver, null);
let statements: o.Statement[] = [];
flattenStatements(stmt.visit(visitor, _Mode.Statement), statements);
return statements;
}
@@ -67,14 +67,16 @@ function convertToStatementIfNeeded(mode: _Mode, expr: o.Expression): o.Expressi
}
class _AstToIrVisitor implements cdAst.AstVisitor {
private _map = new Map<cdAst.AST, cdAst.AST>();
public needsValueUnwrapper: boolean = false;
constructor(
private _nameResolver: NameResolver, private _implicitReceiver: o.Expression,
private _valueUnwrapper: o.ReadVarExpr) {}
visitBinary(ast: cdAst.Binary, mode: _Mode): any {
var op: any /** TODO #9100 */;
var op: o.BinaryOperator;
switch (ast.operation) {
case '+':
op = o.BinaryOperator.Plus;
@@ -128,105 +130,115 @@ class _AstToIrVisitor implements cdAst.AstVisitor {
return convertToStatementIfNeeded(
mode,
new o.BinaryOperatorExpr(
op, ast.left.visit(this, _Mode.Expression), ast.right.visit(this, _Mode.Expression)));
op, this.visit(ast.left, _Mode.Expression), this.visit(ast.right, _Mode.Expression)));
}
visitChain(ast: cdAst.Chain, mode: _Mode): any {
ensureStatementMode(mode, ast);
return this.visitAll(ast.expressions, mode);
}
visitConditional(ast: cdAst.Conditional, mode: _Mode): any {
var value: o.Expression = ast.condition.visit(this, _Mode.Expression);
const value: o.Expression = this.visit(ast.condition, _Mode.Expression);
return convertToStatementIfNeeded(
mode,
value.conditional(
ast.trueExp.visit(this, _Mode.Expression), ast.falseExp.visit(this, _Mode.Expression)));
this.visit(ast.trueExp, _Mode.Expression), this.visit(ast.falseExp, _Mode.Expression)));
}
visitPipe(ast: cdAst.BindingPipe, mode: _Mode): any {
var input = ast.exp.visit(this, _Mode.Expression);
var args = this.visitAll(ast.args, _Mode.Expression);
var value = this._nameResolver.callPipe(ast.name, input, args);
const input = this.visit(ast.exp, _Mode.Expression);
const args = this.visitAll(ast.args, _Mode.Expression);
const value = this._nameResolver.callPipe(ast.name, input, args);
this.needsValueUnwrapper = true;
return convertToStatementIfNeeded(mode, this._valueUnwrapper.callMethod('unwrap', [value]));
}
visitFunctionCall(ast: cdAst.FunctionCall, mode: _Mode): any {
return convertToStatementIfNeeded(
mode,
ast.target.visit(this, _Mode.Expression).callFn(this.visitAll(ast.args, _Mode.Expression)));
this.visit(ast.target, _Mode.Expression).callFn(this.visitAll(ast.args, _Mode.Expression)));
}
visitImplicitReceiver(ast: cdAst.ImplicitReceiver, mode: _Mode): any {
ensureExpressionMode(mode, ast);
return IMPLICIT_RECEIVER;
}
visitInterpolation(ast: cdAst.Interpolation, mode: _Mode): any {
ensureExpressionMode(mode, ast);
var args = [o.literal(ast.expressions.length)];
for (var i = 0; i < ast.strings.length - 1; i++) {
const args = [o.literal(ast.expressions.length)];
for (let i = 0; i < ast.strings.length - 1; i++) {
args.push(o.literal(ast.strings[i]));
args.push(ast.expressions[i].visit(this, _Mode.Expression));
args.push(this.visit(ast.expressions[i], _Mode.Expression));
}
args.push(o.literal(ast.strings[ast.strings.length - 1]));
return o.importExpr(Identifiers.interpolate).callFn(args);
}
visitKeyedRead(ast: cdAst.KeyedRead, mode: _Mode): any {
return convertToStatementIfNeeded(
mode, ast.obj.visit(this, _Mode.Expression).key(ast.key.visit(this, _Mode.Expression)));
mode, this.visit(ast.obj, _Mode.Expression).key(this.visit(ast.key, _Mode.Expression)));
}
visitKeyedWrite(ast: cdAst.KeyedWrite, mode: _Mode): any {
var obj: o.Expression = ast.obj.visit(this, _Mode.Expression);
var key: o.Expression = ast.key.visit(this, _Mode.Expression);
var value: o.Expression = ast.value.visit(this, _Mode.Expression);
const obj: o.Expression = this.visit(ast.obj, _Mode.Expression);
const key: o.Expression = this.visit(ast.key, _Mode.Expression);
const value: o.Expression = this.visit(ast.value, _Mode.Expression);
return convertToStatementIfNeeded(mode, obj.key(key).set(value));
}
visitLiteralArray(ast: cdAst.LiteralArray, mode: _Mode): any {
return convertToStatementIfNeeded(
mode, this._nameResolver.createLiteralArray(this.visitAll(ast.expressions, mode)));
}
visitLiteralMap(ast: cdAst.LiteralMap, mode: _Mode): any {
var parts: any[] /** TODO #9100 */ = [];
for (var i = 0; i < ast.keys.length; i++) {
parts.push([ast.keys[i], ast.values[i].visit(this, _Mode.Expression)]);
let parts: any[] = [];
for (let i = 0; i < ast.keys.length; i++) {
parts.push([ast.keys[i], this.visit(ast.values[i], _Mode.Expression)]);
}
return convertToStatementIfNeeded(mode, this._nameResolver.createLiteralMap(parts));
}
visitLiteralPrimitive(ast: cdAst.LiteralPrimitive, mode: _Mode): any {
return convertToStatementIfNeeded(mode, o.literal(ast.value));
}
visitMethodCall(ast: cdAst.MethodCall, mode: _Mode): any {
var args = this.visitAll(ast.args, _Mode.Expression);
var result: any /** TODO #9100 */ = null;
var receiver = ast.receiver.visit(this, _Mode.Expression);
if (receiver === IMPLICIT_RECEIVER) {
var varExpr = this._nameResolver.getLocal(ast.name);
if (isPresent(varExpr)) {
result = varExpr.callFn(args);
} else {
receiver = this._implicitReceiver;
const leftMostSafe = this.leftMostSafeNode(ast);
if (leftMostSafe) {
return this.convertSafeAccess(ast, leftMostSafe, mode);
} else {
const args = this.visitAll(ast.args, _Mode.Expression);
let result: any = null;
let receiver = this.visit(ast.receiver, _Mode.Expression);
if (receiver === IMPLICIT_RECEIVER) {
var varExpr = this._nameResolver.getLocal(ast.name);
if (isPresent(varExpr)) {
result = varExpr.callFn(args);
} else {
receiver = this._implicitReceiver;
}
}
if (isBlank(result)) {
result = receiver.callMethod(ast.name, args);
}
return convertToStatementIfNeeded(mode, result);
}
if (isBlank(result)) {
result = receiver.callMethod(ast.name, args);
}
return convertToStatementIfNeeded(mode, result);
}
visitPrefixNot(ast: cdAst.PrefixNot, mode: _Mode): any {
return convertToStatementIfNeeded(mode, o.not(ast.expression.visit(this, _Mode.Expression)));
return convertToStatementIfNeeded(mode, o.not(this.visit(ast.expression, _Mode.Expression)));
}
visitPropertyRead(ast: cdAst.PropertyRead, mode: _Mode): any {
var result: any /** TODO #9100 */ = null;
var receiver = ast.receiver.visit(this, _Mode.Expression);
if (receiver === IMPLICIT_RECEIVER) {
result = this._nameResolver.getLocal(ast.name);
const leftMostSafe = this.leftMostSafeNode(ast);
if (leftMostSafe) {
return this.convertSafeAccess(ast, leftMostSafe, mode);
} else {
let result: any = null;
var receiver = this.visit(ast.receiver, _Mode.Expression);
if (receiver === IMPLICIT_RECEIVER) {
result = this._nameResolver.getLocal(ast.name);
if (isBlank(result)) {
receiver = this._implicitReceiver;
}
}
if (isBlank(result)) {
receiver = this._implicitReceiver;
result = receiver.prop(ast.name);
}
return convertToStatementIfNeeded(mode, result);
}
if (isBlank(result)) {
result = receiver.prop(ast.name);
}
return convertToStatementIfNeeded(mode, result);
}
visitPropertyWrite(ast: cdAst.PropertyWrite, mode: _Mode): any {
var receiver: o.Expression = ast.receiver.visit(this, _Mode.Expression);
let receiver: o.Expression = this.visit(ast.receiver, _Mode.Expression);
if (receiver === IMPLICIT_RECEIVER) {
var varExpr = this._nameResolver.getLocal(ast.name);
if (isPresent(varExpr)) {
@@ -235,23 +247,125 @@ class _AstToIrVisitor implements cdAst.AstVisitor {
receiver = this._implicitReceiver;
}
return convertToStatementIfNeeded(
mode, receiver.prop(ast.name).set(ast.value.visit(this, _Mode.Expression)));
mode, receiver.prop(ast.name).set(this.visit(ast.value, _Mode.Expression)));
}
visitSafePropertyRead(ast: cdAst.SafePropertyRead, mode: _Mode): any {
var receiver = ast.receiver.visit(this, _Mode.Expression);
return convertToStatementIfNeeded(
mode, receiver.isBlank().conditional(o.NULL_EXPR, receiver.prop(ast.name)));
return this.convertSafeAccess(ast, this.leftMostSafeNode(ast), mode);
}
visitSafeMethodCall(ast: cdAst.SafeMethodCall, mode: _Mode): any {
var receiver = ast.receiver.visit(this, _Mode.Expression);
var args = this.visitAll(ast.args, _Mode.Expression);
return convertToStatementIfNeeded(
mode, receiver.isBlank().conditional(o.NULL_EXPR, receiver.callMethod(ast.name, args)));
return this.convertSafeAccess(ast, this.leftMostSafeNode(ast), mode);
}
visitAll(asts: cdAst.AST[], mode: _Mode): any { return asts.map(ast => ast.visit(this, mode)); }
visitAll(asts: cdAst.AST[], mode: _Mode): any { return asts.map(ast => this.visit(ast, mode)); }
visitQuote(ast: cdAst.Quote, mode: _Mode): any {
throw new BaseException('Quotes are not supported for evaluation!');
}
private visit(ast: cdAst.AST, mode: _Mode): any {
return (this._map.get(ast) || ast).visit(this, mode);
}
private convertSafeAccess(
ast: cdAst.AST, leftMostSafe: cdAst.SafeMethodCall|cdAst.SafePropertyRead, mode: _Mode): any {
// If the expression contains a safe access node on the left it needs to be converted to
// an expression that guards the access to the member by checking the receiver for blank. As
// execution proceeds from left to right, the left most part of the expression must be guarded
// first but, because member access is left associative, the right side of the expression is at
// the top of the AST. The desired result requires lifting a copy of the the left part of the
// expression up to test it for blank before generating the unguarded version.
// Consider, for example the following expression: a?.b.c?.d.e
// This results in the ast:
// .
// / \
// ?. e
// / \
// . d
// / \
// ?. c
// / \
// a b
// The following tree should be generated:
//
// /---- ? ----\
// / | \
// a /--- ? ---\ null
// / | \
// . . null
// / \ / \
// . c . e
// / \ / \
// a b , d
// / \
// . c
// / \
// a b
//
// Notice that the first guard condition is the left hand of the left most safe access node
// which comes in as leftMostSafe to this routine.
const condition = this.visit(leftMostSafe.receiver, mode).isBlank();
// Convert the ast to an unguarded access to the receiver's member. The map will substitute
// leftMostNode with its unguarded version in the call to `this.visit()`.
if (leftMostSafe instanceof cdAst.SafeMethodCall) {
this._map.set(
leftMostSafe,
new cdAst.MethodCall(
leftMostSafe.span, leftMostSafe.receiver, leftMostSafe.name, leftMostSafe.args));
} else {
this._map.set(
leftMostSafe,
new cdAst.PropertyRead(leftMostSafe.span, leftMostSafe.receiver, leftMostSafe.name));
}
// Recursively convert the node now without the guarded member access.
const access = this.visit(ast, mode);
// Remove the mapping. This is not strictly required as the converter only traverses each node
// once but is safer if the conversion is changed to traverse the nodes more than once.
this._map.delete(leftMostSafe);
// Produce the conditional
return condition.conditional(o.literal(null), access);
}
// Given a expression of the form a?.b.c?.d.e the the left most safe node is
// the (a?.b). The . and ?. are left associative thus can be rewritten as:
// ((((a?.c).b).c)?.d).e. This returns the most deeply nested safe read or
// safe method call as this needs be transform initially to:
// a == null ? null : a.c.b.c?.d.e
// then to:
// a == null ? null : a.b.c == null ? null : a.b.c.d.e
private leftMostSafeNode(ast: cdAst.AST): cdAst.SafePropertyRead|cdAst.SafeMethodCall {
let visit = (visitor: cdAst.AstVisitor, ast: cdAst.AST): any => {
return (this._map.get(ast) || ast).visit(visitor);
};
return ast.visit({
visitBinary(ast: cdAst.Binary) { return null; },
visitChain(ast: cdAst.Chain) { return null; },
visitConditional(ast: cdAst.Conditional) { return null; },
visitFunctionCall(ast: cdAst.FunctionCall) { return null; },
visitImplicitReceiver(ast: cdAst.ImplicitReceiver) { return null; },
visitInterpolation(ast: cdAst.Interpolation) { return null; },
visitKeyedRead(ast: cdAst.KeyedRead) { return visit(this, ast.obj); },
visitKeyedWrite(ast: cdAst.KeyedWrite) { return null; },
visitLiteralArray(ast: cdAst.LiteralArray) { return null; },
visitLiteralMap(ast: cdAst.LiteralMap) { return null; },
visitLiteralPrimitive(ast: cdAst.LiteralPrimitive) { return null; },
visitMethodCall(ast: cdAst.MethodCall) { return visit(this, ast.receiver); },
visitPipe(ast: cdAst.BindingPipe) { return null; },
visitPrefixNot(ast: cdAst.PrefixNot) { return null; },
visitPropertyRead(ast: cdAst.PropertyRead) { return visit(this, ast.receiver); },
visitPropertyWrite(ast: cdAst.PropertyWrite) { return null; },
visitQuote(ast: cdAst.Quote) { return null; },
visitSafeMethodCall(ast: cdAst.SafeMethodCall) { return visit(this, ast.receiver) || ast; },
visitSafePropertyRead(ast: cdAst.SafePropertyRead) {
return visit(this, ast.receiver) || ast;
}
});
}
}
function flattenStatements(arg: any, output: o.Statement[]) {
@@ -277,6 +277,36 @@ export function main() {
ctx.detectChanges(false);
expect(renderLog.log).toEqual(['someProp=MTV']);
}));
it('should support short-circuting safe navigation', fakeAsync(() => {
const ctx = _bindSimpleValue('value?.address.city', PersonHolder);
ctx.componentInstance.value = null;
ctx.detectChanges(false);
expect(renderLog.log).toEqual(['someProp=null']);
}));
it('should support nested short-circuting safe navigation', fakeAsync(() => {
const ctx = _bindSimpleValue('value.value?.address.city', PersonHolderHolder);
ctx.componentInstance.value = new PersonHolder();
ctx.detectChanges(false);
expect(renderLog.log).toEqual(['someProp=null']);
}));
it('should support chained short-circuting safe navigation', fakeAsync(() => {
const ctx = _bindSimpleValue('value?.value?.address.city', PersonHolderHolder);
ctx.detectChanges(false);
expect(renderLog.log).toEqual(['someProp=null']);
}));
it('should still throw if right-side would throw', fakeAsync(() => {
expect(() => {
const ctx = _bindSimpleValue('value?.address.city', PersonHolder);
const person = new Person();
person.address = null;
ctx.componentInstance.value = person;
ctx.detectChanges(false);
}).toThrow();
}));
});
it('should support method calls', fakeAsync(() => {
@@ -1460,3 +1490,22 @@ class Uninitialized {
class TestData {
public a: any;
}
@Component({selector: 'root'})
class TestDataWithGetter {
public fn: Function;
get a() { return this.fn(); }
}
class Holder<T> {
value: T;
}
@Component({selector: 'root'})
class PersonHolder extends Holder<Person> {
}
@Component({selector: 'root'})
class PersonHolderHolder extends Holder<Holder<Person>> {
}

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