JSLexicalEnvironment.cpp   [plain text]

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#include "config.h"
#include "JSLexicalEnvironment.h"

#include "HeapSnapshotBuilder.h"
#include "Interpreter.h"
#include "JSFunction.h"
#include "JSCInlines.h"

namespace JSC {

const ClassInfo JSLexicalEnvironment::s_info = { "JSLexicalEnvironment", &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(JSLexicalEnvironment) };

void JSLexicalEnvironment::visitChildren(JSCell* cell, SlotVisitor& visitor)
{
    auto* thisObject = jsCast<JSLexicalEnvironment*>(cell);
    ASSERT_GC_OBJECT_INHERITS(thisObject, info());
    Base::visitChildren(thisObject, visitor);
    visitor.appendValuesHidden(thisObject->variables(), thisObject->symbolTable()->scopeSize());
}

void JSLexicalEnvironment::heapSnapshot(JSCell* cell, HeapSnapshotBuilder& builder)
{
    auto* thisObject = jsCast<JSLexicalEnvironment*>(cell);
    Base::heapSnapshot(cell, builder);

    ConcurrentJSLocker locker(thisObject->symbolTable()->m_lock);
    SymbolTable::Map::iterator end = thisObject->symbolTable()->end(locker);
    for (SymbolTable::Map::iterator it = thisObject->symbolTable()->begin(locker); it != end; ++it) {
        SymbolTableEntry::Fast entry = it->value;
        ASSERT(!entry.isNull());
        ScopeOffset offset = entry.scopeOffset();
        if (!thisObject->isValidScopeOffset(offset))
            continue;

        JSValue toValue = thisObject->variableAt(offset).get();
        if (toValue && toValue.isCell())
            builder.appendVariableNameEdge(thisObject, toValue.asCell(), it->key.get());
    }
}

void JSLexicalEnvironment::getOwnNonIndexPropertyNames(JSObject* object, ExecState* exec, PropertyNameArray& propertyNames, EnumerationMode mode)
{
    JSLexicalEnvironment* thisObject = jsCast<JSLexicalEnvironment*>(object);

    {
        ConcurrentJSLocker locker(thisObject->symbolTable()->m_lock);
        SymbolTable::Map::iterator end = thisObject->symbolTable()->end(locker);
        for (SymbolTable::Map::iterator it = thisObject->symbolTable()->begin(locker); it != end; ++it) {
            if (it->value.getAttributes() & PropertyAttribute::DontEnum && !mode.includeDontEnumProperties())
                continue;
            if (!thisObject->isValidScopeOffset(it->value.scopeOffset()))
                continue;
            if (it->key->isSymbol() && !propertyNames.includeSymbolProperties())
                continue;
            propertyNames.add(Identifier::fromUid(exec, it->key.get()));
        }
    }
    // Skip the JSSymbolTableObject's implementation of getOwnNonIndexPropertyNames
    JSObject::getOwnNonIndexPropertyNames(thisObject, exec, propertyNames, mode);
}

bool JSLexicalEnvironment::getOwnPropertySlot(JSObject* object, ExecState* exec, PropertyName propertyName, PropertySlot& slot)
{
    JSLexicalEnvironment* thisObject = jsCast<JSLexicalEnvironment*>(object);

    if (symbolTableGet(thisObject, propertyName, slot))
        return true;

    VM& vm = exec->vm();
    unsigned attributes;
    if (JSValue value = thisObject->getDirect(vm, propertyName, attributes)) {
        slot.setValue(thisObject, attributes, value);
        return true;
    }

    // We don't call through to JSObject because there's no way to give a 
    // lexical environment object getter properties or a prototype.
    ASSERT(!thisObject->hasGetterSetterProperties(vm));
    ASSERT(thisObject->getPrototypeDirect(vm).isNull());
    return false;
}

bool JSLexicalEnvironment::put(JSCell* cell, ExecState* exec, PropertyName propertyName, JSValue value, PutPropertySlot& slot)
{
    JSLexicalEnvironment* thisObject = jsCast<JSLexicalEnvironment*>(cell);
    ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(thisObject));

    bool shouldThrowReadOnlyError = slot.isStrictMode() || thisObject->isLexicalScope();
    bool ignoreReadOnlyErrors = false;
    bool putResult = false;
    if (symbolTablePutInvalidateWatchpointSet(thisObject, exec, propertyName, value, shouldThrowReadOnlyError, ignoreReadOnlyErrors, putResult))
        return putResult;

    // We don't call through to JSObject because __proto__ and getter/setter 
    // properties are non-standard extensions that other implementations do not
    // expose in the lexicalEnvironment object.
    ASSERT(!thisObject->hasGetterSetterProperties(exec->vm()));
    return thisObject->putOwnDataProperty(exec->vm(), propertyName, value, slot);
}

bool JSLexicalEnvironment::deleteProperty(JSCell* cell, ExecState* exec, PropertyName propertyName)
{
    VM& vm = exec->vm();
    if (propertyName == vm.propertyNames->arguments)
        return false;

    return Base::deleteProperty(cell, exec, propertyName);
}

} // namespace JSC