nodes.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
*  Copyright (C) 1999-2002 Harri Porten ([e-mail])
*  Copyright (C) 2001 Peter Kelly ([e-mail])
*  Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
*  Copyright (C) 2007 Cameron Zwarich ([e-mail])
*  Copyright (C) 2007 Maks Orlovich
*  Copyright (C) 2007 Eric Seidel <[e-mail]>
*
*  This library is free software; you can redistribute it and/or
*  modify it under the terms of the GNU Library General Public
*  License as published by the Free Software Foundation; either
*  version 2 of the License, or (at your option) any later version.
*
*  This library is distributed in the hope that it will be useful,
*  but WITHOUT ANY WARRANTY; without even the implied warranty of
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
*  Library General Public License for more details.
*
*  You should have received a copy of the GNU Library General Public License
*  along with this library; see the file COPYING.LIB.  If not, write to
*  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
*  Boston, MA 02110-1301, USA.
*
*/

#include "config.h"
#include "Nodes.h"

#include "BytecodeGenerator.h"
#include "CallFrame.h"
#include "JSGlobalObject.h"
#include "JSStaticScopeObject.h"
#include "LabelScope.h"
#include "Parser.h"
#include "PropertyNameArray.h"
#include "RegExpObject.h"
#include "SamplingTool.h"
#include "Debugger.h"
#include "Lexer.h"
#include "Operations.h"
#include <math.h>
#include <wtf/Assertions.h>
#include <wtf/HashCountedSet.h>
#include <wtf/HashSet.h>
#include <wtf/MathExtras.h>
#include <wtf/RefCountedLeakCounter.h>
#include <wtf/Threading.h>

using namespace WTF;

namespace JSC {

static void substitute(UString& string, const UString& substring) JSC_FAST_CALL;

// ------------------------------ NodeReleaser --------------------------------

class NodeReleaser : Noncopyable {
public:
    // Call this function inside the destructor of a class derived from Node.
    // This will traverse the tree below this node, destroying all of those nodes,
    // but without relying on recursion.
    static void releaseAllNodes(ParserRefCounted* root);

    // Call this on each node in a the releaseNodes virtual function.
    // It gives the node to the NodeReleaser, which will then release the
    // node later at the end of the releaseAllNodes process.
    template <typename T> void release(RefPtr<T>& node) { if (node) adopt(node.release()); }
    void release(RefPtr<FunctionBodyNode>& node) { if (node) adoptFunctionBodyNode(node); }

private:
    NodeReleaser() { }
    ~NodeReleaser() { }

    void adopt(PassRefPtr<ParserRefCounted>);
    void adoptFunctionBodyNode(RefPtr<FunctionBodyNode>&);

    typedef Vector<RefPtr<ParserRefCounted> > NodeReleaseVector;
    OwnPtr<NodeReleaseVector> m_vector;
};

void NodeReleaser::releaseAllNodes(ParserRefCounted* root)
{
    ASSERT(root);
    NodeReleaser releaser;
    root->releaseNodes(releaser);
    if (!releaser.m_vector)
        return;
    // Note: The call to release.m_vector->size() is intentionally inside
    // the loop, since calls to releaseNodes are expected to increase the size.
    for (size_t i = 0; i < releaser.m_vector->size(); ++i) {
        ParserRefCounted* node = (*releaser.m_vector)[i].get();
        if (node->hasOneRef())
            node->releaseNodes(releaser);
    }
}

void NodeReleaser::adopt(PassRefPtr<ParserRefCounted> node)
{
    ASSERT(node);
    if (!node->hasOneRef())
        return;
    if (!m_vector)
        m_vector.set(new NodeReleaseVector);
    m_vector->append(node);
}

void NodeReleaser::adoptFunctionBodyNode(RefPtr<FunctionBodyNode>& functionBodyNode)
{
    // This sidesteps a problem where if you assign a PassRefPtr<FunctionBodyNode>
    // to a PassRefPtr<Node> we leave the two reference counts (FunctionBodyNode
    // and ParserRefCounted) unbalanced. It would be nice to fix this problem in
    // a cleaner way -- perhaps we could remove the FunctionBodyNode reference
    // count at some point.
    RefPtr<Node> node = functionBodyNode;
    functionBodyNode = 0;
    adopt(node.release());
}

// ------------------------------ ParserRefCounted -----------------------------------------

#ifndef NDEBUG
static RefCountedLeakCounter parserRefCountedCounter("JSC::Node");
#endif

ParserRefCounted::ParserRefCounted(JSGlobalData* globalData)
    : m_globalData(globalData)
{
#ifndef NDEBUG
    parserRefCountedCounter.increment();
#endif
    if (!m_globalData->newParserObjects)
        m_globalData->newParserObjects = new HashSet<ParserRefCounted*>;
    m_globalData->newParserObjects->add(this);
    ASSERT(m_globalData->newParserObjects->contains(this));
}

ParserRefCounted::~ParserRefCounted()
{
#ifndef NDEBUG
    parserRefCountedCounter.decrement();
#endif
}

void ParserRefCounted::releaseNodes(NodeReleaser&)
{
}

void ParserRefCounted::ref()
{
    // bumping from 0 to 1 is just removing from the new nodes set
    if (m_globalData->newParserObjects) {
        HashSet<ParserRefCounted*>::iterator it = m_globalData->newParserObjects->find(this);
        if (it != m_globalData->newParserObjects->end()) {
            m_globalData->newParserObjects->remove(it);
            ASSERT(!m_globalData->parserObjectExtraRefCounts || !m_globalData->parserObjectExtraRefCounts->contains(this));
            return;
        }
    }

    ASSERT(!m_globalData->newParserObjects || !m_globalData->newParserObjects->contains(this));

    if (!m_globalData->parserObjectExtraRefCounts)
        m_globalData->parserObjectExtraRefCounts = new HashCountedSet<ParserRefCounted*>;
    m_globalData->parserObjectExtraRefCounts->add(this);
}

void ParserRefCounted::deref()
{
    ASSERT(!m_globalData->newParserObjects || !m_globalData->newParserObjects->contains(this));

    if (!m_globalData->parserObjectExtraRefCounts) {
        delete this;
        return;
    }

    HashCountedSet<ParserRefCounted*>::iterator it = m_globalData->parserObjectExtraRefCounts->find(this);
    if (it == m_globalData->parserObjectExtraRefCounts->end())
        delete this;
    else
        m_globalData->parserObjectExtraRefCounts->remove(it);
}

bool ParserRefCounted::hasOneRef()
{
    if (m_globalData->newParserObjects && m_globalData->newParserObjects->contains(this)) {
        ASSERT(!m_globalData->parserObjectExtraRefCounts || !m_globalData->parserObjectExtraRefCounts->contains(this));
        return false;
    }

    ASSERT(!m_globalData->newParserObjects || !m_globalData->newParserObjects->contains(this));

    if (!m_globalData->parserObjectExtraRefCounts)
        return true;

    return !m_globalData->parserObjectExtraRefCounts->contains(this);
}

void ParserRefCounted::deleteNewObjects(JSGlobalData* globalData)
{
    if (!globalData->newParserObjects)
        return;

#ifndef NDEBUG
    HashSet<ParserRefCounted*>::iterator end = globalData->newParserObjects->end();
    for (HashSet<ParserRefCounted*>::iterator it = globalData->newParserObjects->begin(); it != end; ++it)
        ASSERT(!globalData->parserObjectExtraRefCounts || !globalData->parserObjectExtraRefCounts->contains(*it));
#endif
    deleteAllValues(*globalData->newParserObjects);
    delete globalData->newParserObjects;
    globalData->newParserObjects = 0;
}

// ------------------------------ Node --------------------------------

Node::Node(JSGlobalData* globalData)
    : ParserRefCounted(globalData)
{
    m_line = globalData->lexer->lineNo();
}

// ------------------------------ ThrowableExpressionData --------------------------------

static void substitute(UString& string, const UString& substring)
{
    int position = string.find("%s");
    ASSERT(position != -1);
    UString newString = string.substr(0, position);
    newString.append(substring);
    newString.append(string.substr(position + 2));
    string = newString;
}

RegisterID* ThrowableExpressionData::emitThrowError(BytecodeGenerator& generator, ErrorType e, const char* msg)
{
    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
    RegisterID* exception = generator.emitNewError(generator.newTemporary(), e, jsString(generator.globalData(), msg));
    generator.emitThrow(exception);
    return exception;
}

RegisterID* ThrowableExpressionData::emitThrowError(BytecodeGenerator& generator, ErrorType e, const char* msg, const Identifier& label)
{
    UString message = msg;
    substitute(message, label.ustring());
    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
    RegisterID* exception = generator.emitNewError(generator.newTemporary(), e, jsString(generator.globalData(), message));
    generator.emitThrow(exception);
    return exception;
}
    
// ------------------------------ StatementNode --------------------------------

StatementNode::StatementNode(JSGlobalData* globalData)
    : Node(globalData)
    , m_lastLine(-1)
{
}

void StatementNode::setLoc(int firstLine, int lastLine)
{
    m_line = firstLine;
    m_lastLine = lastLine;
}

// ------------------------------ SourceElements --------------------------------

void SourceElements::append(PassRefPtr<StatementNode> statement)
{
    if (statement->isEmptyStatement())
        return;

    m_statements.append(statement);
}

// ------------------------------ NullNode -------------------------------------

RegisterID* NullNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    if (dst == generator.ignoredResult())
        return 0;
    return generator.emitLoad(dst, jsNull());
}

// ------------------------------ BooleanNode ----------------------------------

RegisterID* BooleanNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    if (dst == generator.ignoredResult())
        return 0;
    return generator.emitLoad(dst, m_value);
}

// ------------------------------ NumberNode -----------------------------------

RegisterID* NumberNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    if (dst == generator.ignoredResult())
        return 0;
    return generator.emitLoad(dst, m_double);
}

// ------------------------------ StringNode -----------------------------------

RegisterID* StringNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    if (dst == generator.ignoredResult())
        return 0;
    return generator.emitLoad(dst, m_value);
}

// ------------------------------ RegExpNode -----------------------------------

RegisterID* RegExpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    RefPtr<RegExp> regExp = RegExp::create(generator.globalData(), m_pattern, m_flags);
    if (!regExp->isValid())
        return emitThrowError(generator, SyntaxError, ("Invalid regular expression: " + UString(regExp->errorMessage())).UTF8String().c_str());
    if (dst == generator.ignoredResult())
        return 0;
    return generator.emitNewRegExp(generator.finalDestination(dst), regExp.get());
}

// ------------------------------ ThisNode -------------------------------------

RegisterID* ThisNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    if (dst == generator.ignoredResult())
        return 0;
    return generator.moveToDestinationIfNeeded(dst, generator.thisRegister());
}

// ------------------------------ ResolveNode ----------------------------------

bool ResolveNode::isPure(BytecodeGenerator& generator) const
{
    return generator.isLocal(m_ident);
}

RegisterID* ResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    if (RegisterID* local = generator.registerFor(m_ident)) {
        if (dst == generator.ignoredResult())
            return 0;
        return generator.moveToDestinationIfNeeded(dst, local);
    }
    
    generator.emitExpressionInfo(m_startOffset + m_ident.size(), m_ident.size(), 0);
    return generator.emitResolve(generator.finalDestination(dst), m_ident);
}

// ------------------------------ ElementNode ------------------------------------

ElementNode::~ElementNode()
{
    NodeReleaser::releaseAllNodes(this);
}

void ElementNode::releaseNodes(NodeReleaser& releaser)
{
    releaser.release(m_next);
    releaser.release(m_node);
}

// ------------------------------ ArrayNode ------------------------------------

ArrayNode::~ArrayNode()
{
    NodeReleaser::releaseAllNodes(this);
}