| // Copyright (c) 2013, 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. |
| |
| part of types; |
| |
| /** |
| * A flat type mask is a type mask that has been flatten to contain a |
| * base type. |
| */ |
| class FlatTypeMask implements TypeMask { |
| |
| static const int EMPTY = 0; |
| static const int EXACT = 1; |
| static const int SUBCLASS = 2; |
| static const int SUBTYPE = 3; |
| |
| final DartType base; |
| final int flags; |
| |
| FlatTypeMask(DartType base, int kind, bool isNullable) |
| : this.internal(base, (kind << 1) | (isNullable ? 1 : 0)); |
| |
| FlatTypeMask.empty() |
| : this.internal(null, (EMPTY << 1) | 1); |
| FlatTypeMask.exact(DartType base) |
| : this.internal(base, (EXACT << 1) | 1); |
| FlatTypeMask.subclass(DartType base) |
| : this.internal(base, (SUBCLASS << 1) | 1); |
| FlatTypeMask.subtype(DartType base) |
| : this.internal(base, (SUBTYPE << 1) | 1); |
| |
| FlatTypeMask.nonNullEmpty() |
| : this.internal(null, EMPTY << 1); |
| FlatTypeMask.nonNullExact(DartType base) |
| : this.internal(base, EXACT << 1); |
| FlatTypeMask.nonNullSubclass(DartType base) |
| : this.internal(base, SUBCLASS << 1); |
| FlatTypeMask.nonNullSubtype(DartType base) |
| : this.internal(base, SUBTYPE << 1); |
| |
| FlatTypeMask.internal(DartType base, this.flags) |
| : this.base = transformBase(base) { |
| assert(base == null || !(isExact && base.isDynamic)); |
| } |
| |
| // TODO(kasperl): We temporarily transform the base to be the raw |
| // variant of the type. Long term, we're going to keep the class |
| // element corresponding to the type in the mask instead. |
| static DartType transformBase(DartType base) { |
| if (base == null) { |
| return null; |
| } else if (base.kind != TypeKind.INTERFACE) { |
| assert(base.kind == TypeKind.INTERFACE); |
| return null; |
| } else { |
| assert(!base.isMalformed); |
| return base.asRaw(); |
| } |
| } |
| |
| bool get isEmpty => (flags >> 1) == EMPTY; |
| bool get isExact => (flags >> 1) == EXACT; |
| bool get isNullable => (flags & 1) != 0; |
| bool get isUnion => false; |
| |
| // TODO(kasperl): Get rid of these. They should not be a visible |
| // part of the implementation because they make it hard to add |
| // proper union types if we ever want to. |
| bool get isSubclass => (flags >> 1) == SUBCLASS; |
| bool get isSubtype => (flags >> 1) == SUBTYPE; |
| |
| TypeMask nullable() { |
| return isNullable ? this : new FlatTypeMask.internal(base, flags | 1); |
| } |
| |
| TypeMask nonNullable() { |
| return isNullable ? new FlatTypeMask.internal(base, flags & ~1) : this; |
| } |
| |
| TypeMask simplify(Compiler compiler) => this; |
| |
| bool contains(DartType type, Compiler compiler) { |
| if (isEmpty) { |
| return false; |
| } else if (identical(base.element, type.element)) { |
| return true; |
| } else if (isExact) { |
| return false; |
| } else if (isSubclass) { |
| return isSubclassOf(type, base, compiler); |
| } else { |
| assert(isSubtype); |
| return isSubtypeOf(type, base, compiler); |
| } |
| } |
| |
| bool containsOnlyInt(Compiler compiler) { |
| return base.element == compiler.intClass |
| || base.element == compiler.backend.intImplementation; |
| } |
| |
| bool containsOnlyDouble(Compiler compiler) { |
| return base.element == compiler.doubleClass |
| || base.element == compiler.backend.doubleImplementation; |
| } |
| |
| bool containsOnlyNum(Compiler compiler) { |
| return base.element == compiler.numClass |
| || base.element == compiler.backend.numImplementation; |
| } |
| |
| bool containsOnlyNull(Compiler compiler) { |
| return base.element == compiler.nullClass |
| || base.element == compiler.backend.nullImplementation; |
| } |
| |
| bool containsOnlyBool(Compiler compiler) { |
| return base.element == compiler.boolClass |
| || base.element == compiler.backend.boolImplementation; |
| } |
| |
| bool containsOnlyString(Compiler compiler) { |
| return base.element == compiler.stringClass |
| || base.element == compiler.backend.stringImplementation; |
| } |
| |
| bool containsOnly(ClassElement cls) { |
| return base.element == cls; |
| } |
| |
| bool satisfies(ClassElement cls, Compiler compiler) { |
| if (isEmpty) return false; |
| return base.element == cls |
| || isSubtypeOf(base, cls.computeType(compiler).asRaw(), compiler); |
| } |
| |
| /** |
| * Returns the [ClassElement] if this type represents a single class, |
| * otherwise returns `null`. This method is conservative. |
| */ |
| ClassElement singleClass(Compiler compiler) { |
| if (isEmpty) return null; |
| if (isNullable) return null; // It is Null and some other class. |
| ClassElement element = base.element; |
| if (isExact) { |
| return element; |
| } else if (isSubclass) { |
| return compiler.world.hasAnySubclass(element) ? null : element; |
| } else { |
| assert(isSubtype); |
| return null; |
| } |
| } |
| |
| /** |
| * Returns whether or not this type mask contains all types. |
| */ |
| bool containsAll(Compiler compiler) { |
| if (isEmpty || isExact) return false; |
| return identical(base.element, compiler.objectClass) |
| || identical(base.element, compiler.dynamicClass); |
| } |
| |
| TypeMask union(TypeMask other, Compiler compiler) { |
| assert(other != null); |
| if (other is! FlatTypeMask) return other.union(this, compiler); |
| FlatTypeMask flatOther = other; |
| if (isEmpty) { |
| return isNullable ? flatOther.nullable() : flatOther; |
| } else if (flatOther.isEmpty) { |
| return flatOther.isNullable ? nullable() : this; |
| } else if (base == flatOther.base) { |
| return unionSame(flatOther, compiler); |
| } else if (isSubclassOf(flatOther.base, base, compiler)) { |
| return unionSubclass(flatOther, compiler); |
| } else if (isSubclassOf(base, flatOther.base, compiler)) { |
| return flatOther.unionSubclass(this, compiler); |
| } else if (isSubtypeOf(flatOther.base, base, compiler)) { |
| return unionSubtype(flatOther, compiler); |
| } else if (isSubtypeOf(base, flatOther.base, compiler)) { |
| return flatOther.unionSubtype(this, compiler); |
| } else { |
| return new UnionTypeMask._(<FlatTypeMask>[this, flatOther]); |
| } |
| } |
| |
| TypeMask unionSame(FlatTypeMask other, Compiler compiler) { |
| assert(base == other.base); |
| // The two masks share the base type, so we must chose the least |
| // constraining kind (the highest) of the two. If either one of |
| // the masks are nullable the result should be nullable too. |
| int combined = (flags > other.flags) |
| ? flags | (other.flags & 1) |
| : other.flags | (flags & 1); |
| if (flags == combined) { |
| return this; |
| } else if (other.flags == combined) { |
| return other; |
| } else { |
| return new FlatTypeMask.internal(base, combined); |
| } |
| } |
| |
| TypeMask unionSubclass(FlatTypeMask other, Compiler compiler) { |
| assert(isSubclassOf(other.base, base, compiler)); |
| int combined; |
| if (isExact && other.isExact) { |
| // Since the other mask is a subclass of this mask, we need the |
| // resulting union to be a subclass too. If either one of the |
| // masks are nullable the result should be nullable too. |
| combined = (SUBCLASS << 1) | ((flags | other.flags) & 1); |
| } else { |
| // Both masks are at least subclass masks, so we pick the least |
| // constraining kind (the highest) of the two. If either one of |
| // the masks are nullable the result should be nullable too. |
| combined = (flags > other.flags) |
| ? flags | (other.flags & 1) |
| : other.flags | (flags & 1); |
| } |
| return (flags != combined) |
| ? new FlatTypeMask.internal(base, combined) |
| : this; |
| } |
| |
| TypeMask unionSubtype(FlatTypeMask other, Compiler compiler) { |
| assert(isSubtypeOf(other.base, base, compiler)); |
| // Since the other mask is a subtype of this mask, we need the |
| // resulting union to be a subtype too. If either one of the masks |
| // are nullable the result should be nullable too. |
| int combined = (SUBTYPE << 1) | ((flags | other.flags) & 1); |
| return (flags != combined) |
| ? new FlatTypeMask.internal(base, combined) |
| : this; |
| } |
| |
| TypeMask intersection(TypeMask other, Compiler compiler) { |
| assert(other != null); |
| if (other is! FlatTypeMask) return other.intersection(this, compiler); |
| FlatTypeMask flatOther = other; |
| if (isEmpty) { |
| return flatOther.isNullable ? this : nonNullable(); |
| } else if (flatOther.isEmpty) { |
| return isNullable ? flatOther : other.nonNullable(); |
| } else if (base == flatOther.base) { |
| return intersectionSame(flatOther, compiler); |
| } else if (isSubclassOf(flatOther.base, base, compiler)) { |
| return intersectionSubclass(flatOther, compiler); |
| } else if (isSubclassOf(base, flatOther.base, compiler)) { |
| return flatOther.intersectionSubclass(this, compiler); |
| } else if (isSubtypeOf(flatOther.base, base, compiler)) { |
| return intersectionSubtype(flatOther, compiler); |
| } else if (isSubtypeOf(base, flatOther.base, compiler)) { |
| return flatOther.intersectionSubtype(this, compiler); |
| } else { |
| return intersectionDisjoint(flatOther, compiler); |
| } |
| } |
| |
| TypeMask intersectionSame(FlatTypeMask other, Compiler compiler) { |
| assert(base == other.base); |
| // The two masks share the base type, so we must chose the most |
| // constraining kind (the lowest) of the two. Only if both masks |
| // are nullable, will the result be nullable too. |
| int combined = (flags < other.flags) |
| ? flags & ((other.flags & 1) | ~1) |
| : other.flags & ((flags & 1) | ~1); |
| if (flags == combined) { |
| return this; |
| } else if (other.flags == combined) { |
| return other; |
| } else { |
| return new FlatTypeMask.internal(base, combined); |
| } |
| } |
| |
| TypeMask intersectionSubclass(FlatTypeMask other, Compiler compiler) { |
| assert(isSubclassOf(other.base, base, compiler)); |
| // If this mask isn't at least a subclass mask, then the |
| // intersection with the other mask is empty. |
| if (isExact) return intersectionEmpty(other); |
| // Only the other mask puts constraints on the intersection mask, |
| // so base the combined flags on the other mask. Only if both |
| // masks are nullable, will the result be nullable too. |
| int combined = other.flags & ((flags & 1) | ~1); |
| if (other.flags == combined) { |
| return other; |
| } else { |
| return new FlatTypeMask.internal(other.base, combined); |
| } |
| } |
| |
| TypeMask intersectionSubtype(FlatTypeMask other, Compiler compiler) { |
| assert(isSubtypeOf(other.base, base, compiler)); |
| if (!isSubtype) return intersectionHelper(other, compiler); |
| // Only the other mask puts constraints on the intersection mask, |
| // so base the combined flags on the other mask. Only if both |
| // masks are nullable, will the result be nullable too. |
| int combined = other.flags & ((flags & 1) | ~1); |
| if (other.flags == combined) { |
| return other; |
| } else { |
| return new FlatTypeMask.internal(other.base, combined); |
| } |
| } |
| |
| TypeMask intersectionDisjoint(FlatTypeMask other, Compiler compiler) { |
| assert(base != other.base); |
| assert(!isSubtypeOf(base, other.base, compiler)); |
| assert(!isSubtypeOf(other.base, base, compiler)); |
| return intersectionHelper(other, compiler); |
| } |
| |
| TypeMask intersectionHelper(FlatTypeMask other, Compiler compiler) { |
| assert(base != other.base); |
| assert(!isSubclassOf(base, other.base, compiler)); |
| assert(!isSubclassOf(other.base, base, compiler)); |
| // If one of the masks are exact or if both of them are subclass |
| // masks, then the intersection is empty. |
| if (isExact || other.isExact) return intersectionEmpty(other); |
| if (isSubclass && other.isSubclass) return intersectionEmpty(other); |
| assert(isSubtype || other.isSubtype); |
| int kind = (isSubclass || other.isSubclass) ? SUBCLASS : SUBTYPE; |
| // Compute the set of classes that are contained in both type masks. |
| Set<ClassElement> common = commonContainedClasses(this, other, compiler); |
| if (common == null || common.isEmpty) return intersectionEmpty(other); |
| // Narrow down the candidates by only looking at common classes |
| // that do not have a superclass or supertype that will be a |
| // better candidate. |
| Iterable<ClassElement> candidates = common.where((ClassElement each) { |
| bool containsSuperclass = common.contains(each.supertype.element); |
| // If the superclass is also a candidate, then we don't want to |
| // deal with this class. If we're only looking for a subclass we |
| // know we don't have to look at the list of interfaces because |
| // they can never be in the common set. |
| if (containsSuperclass || kind == SUBCLASS) return !containsSuperclass; |
| // Run through the direct supertypes of the class. If the common |
| // set contains the direct supertype of the class, we ignore the |
| // the class because the supertype is a better candidate. |
| for (Link link = each.interfaces; !link.isEmpty; link = link.tail) { |
| if (common.contains(link.head.element)) return false; |
| } |
| return true; |
| }); |
| // Run through the list of candidates and compute the union. The |
| // result will only be nullable if both masks are nullable. |
| int combined = (kind << 1) | (flags & other.flags & 1); |
| TypeMask result; |
| for (ClassElement each in candidates) { |
| TypeMask mask = new FlatTypeMask.internal(each.rawType, combined); |
| result = (result == null) ? mask : result.union(mask, compiler); |
| } |
| return result; |
| } |
| |
| TypeMask intersectionEmpty(FlatTypeMask other) { |
| return new TypeMask(null, EMPTY, isNullable && other.isNullable); |
| } |
| |
| Iterable<ClassElement> containedClasses(Compiler compiler) { |
| Iterable<ClassElement> self = [ base.element ]; |
| if (isExact) { |
| return self; |
| } else { |
| Set<ClassElement> subset = containedSubset(this, compiler); |
| return (subset == null) ? self : [ self, subset ].expand((x) => x); |
| } |
| } |
| |
| /** |
| * Returns whether [element] will be the one used at runtime when being |
| * invoked on an instance of [cls]. [selector] is used to ensure library |
| * privacy is taken into account. |
| */ |
| static bool hasElementIn(ClassElement cls, |
| Selector selector, |
| Element element, |
| Compiler compiler) { |
| // Use [:implementation:] of [element] |
| // because our function set only stores declarations. |
| Element result = findMatchIn(cls, selector, compiler); |
| return result == null |
| ? false |
| : result.implementation == element.implementation; |
| } |
| |
| static Element findMatchIn(ClassElement cls, |
| Selector selector, |
| Compiler compiler) { |
| // Use the [:implementation] of [cls] in case the found [element] |
| // is in the patch class. |
| return cls.implementation.lookupSelector(selector, compiler); |
| } |
| |
| /** |
| * Returns whether [element] is a potential target when being |
| * invoked on this type mask. [selector] is used to ensure library |
| * privacy is taken into account. |
| */ |
| bool canHit(Element element, Selector selector, Compiler compiler) { |
| assert(element.name == selector.name); |
| if (isEmpty) { |
| if (!isNullable) return false; |
| return hasElementIn( |
| compiler.backend.nullImplementation, selector, element, compiler); |
| } |
| |
| // TODO(kasperl): Can't we just avoid creating typed selectors |
| // based of function types? |
| Element self = base.element; |
| if (self.isTypedef()) { |
| // A typedef is a function type that doesn't have any |
| // user-defined members. |
| return false; |
| } |
| |
| ClassElement other = element.getEnclosingClass(); |
| if (compiler.backend.isNullImplementation(other)) { |
| return isNullable; |
| } else if (isExact) { |
| return hasElementIn(self, selector, element, compiler); |
| } else if (isSubclass) { |
| return hasElementIn(self, selector, element, compiler) |
| || other.isSubclassOf(self) |
| || compiler.world.hasAnySubclassThatMixes(self, other); |
| } else { |
| assert(isSubtype); |
| return hasElementIn(self, selector, element, compiler) |
| || other.implementsInterface(self) |
| || other.isSubclassOf(self) |
| || compiler.world.hasAnySubclassThatMixes(self, other) |
| || compiler.world.hasAnySubclassThatImplements(other, base); |
| } |
| } |
| |
| /** |
| * Returns whether a [selector] call on an instance of [cls] |
| * will hit a method at runtime, and not go through [noSuchMethod]. |
| */ |
| static bool hasConcreteMatch(ClassElement cls, |
| Selector selector, |
| Compiler compiler) { |
| Element element = findMatchIn(cls, selector, compiler); |
| if (element == null) return false; |
| |
| if (element.isAbstract(compiler)) { |
| ClassElement enclosingClass = element.getEnclosingClass(); |
| return hasConcreteMatch(enclosingClass.superclass, selector, compiler); |
| } |
| return selector.appliesUntyped(element, compiler); |
| } |
| |
| /** |
| * Returns whether a [selector] call will hit a method at runtime, |
| * and not go through [noSuchMethod]. |
| */ |
| bool willHit(Selector selector, Compiler compiler) { |
| Element cls; |
| if (isEmpty) { |
| if (!isNullable) return false; |
| cls = compiler.backend.nullImplementation; |
| } else { |
| cls = base.element; |
| } |
| |
| if (!cls.isAbstract(compiler)) { |
| return hasConcreteMatch(cls, selector, compiler); |
| } |
| |
| Set<ClassElement> subtypesToCheck; |
| if (isExact) { |
| return false; |
| } else if (isSubtype) { |
| subtypesToCheck = compiler.world.subtypesOf(cls); |
| } else { |
| assert(isSubclass); |
| subtypesToCheck = compiler.world.subclassesOf(cls); |
| } |
| |
| return subtypesToCheck != null |
| && subtypesToCheck.every((ClassElement cls) { |
| return cls.isAbstract(compiler) |
| ? true |
| : hasConcreteMatch(cls, selector, compiler); |
| }); |
| } |
| |
| Element locateSingleElement(Selector selector, Compiler compiler) { |
| if (isEmpty) return null; |
| Iterable<Element> targets = compiler.world.allFunctions.filter(selector); |
| if (targets.length != 1) return null; |
| Element result = targets.first; |
| ClassElement enclosing = result.getEnclosingClass(); |
| // We only return the found element if it is guaranteed to be |
| // implemented on the exact receiver type. It could be found in a |
| // subclass or in an inheritance-wise unrelated class in case of |
| // subtype selectors. |
| ClassElement cls = base.element; |
| return (cls.isSubclassOf(enclosing)) ? result : null; |
| } |
| |
| bool operator ==(var other) { |
| if (other is !FlatTypeMask) return false; |
| FlatTypeMask otherMask = other; |
| return (flags == otherMask.flags) && (base == otherMask.base); |
| } |
| |
| int get hashCode { |
| return (base == null ? 0 : base.hashCode) + 31 * flags.hashCode; |
| } |
| |
| String toString() { |
| if (isEmpty) return isNullable ? '[null]' : '[empty]'; |
| StringBuffer buffer = new StringBuffer(); |
| if (isNullable) buffer.write('null|'); |
| if (isExact) buffer.write('exact='); |
| if (isSubclass) buffer.write('subclass='); |
| if (isSubtype) buffer.write('subtype='); |
| buffer.write(base.element.name.slowToString()); |
| return "[$buffer]"; |
| } |
| |
| static bool isSubclassOf(DartType x, DartType y, Compiler compiler) { |
| ClassElement xElement = x.element; |
| ClassElement yElement = y.element; |
| Set<ClassElement> subclasses = compiler.world.subclassesOf(yElement); |
| return (subclasses != null) ? subclasses.contains(xElement) : false; |
| } |
| |
| static bool isSubtypeOf(DartType x, DartType y, Compiler compiler) { |
| ClassElement xElement = x.element; |
| ClassElement yElement = y.element; |
| Set<ClassElement> subtypes = compiler.world.subtypesOf(yElement); |
| return (subtypes != null) ? subtypes.contains(xElement) : false; |
| } |
| |
| static Set<ClassElement> commonContainedClasses(FlatTypeMask x, |
| FlatTypeMask y, |
| Compiler compiler) { |
| Set<ClassElement> xSubset = containedSubset(x, compiler); |
| if (xSubset == null) return null; |
| Set<ClassElement> ySubset = containedSubset(y, compiler); |
| if (ySubset == null) return null; |
| Set<ClassElement> smallSet, largeSet; |
| if (xSubset.length <= ySubset.length) { |
| smallSet = xSubset; |
| largeSet = ySubset; |
| } else { |
| smallSet = ySubset; |
| largeSet = xSubset; |
| } |
| var result = smallSet.where((ClassElement each) => largeSet.contains(each)); |
| return result.toSet(); |
| } |
| |
| static Set<ClassElement> containedSubset(FlatTypeMask x, Compiler compiler) { |
| ClassElement element = x.base.element; |
| if (x.isExact) { |
| return null; |
| } else if (x.isSubclass) { |
| return compiler.world.subclassesOf(element); |
| } else { |
| assert(x.isSubtype); |
| return compiler.world.subtypesOf(element); |
| } |
| } |
| } |
