node.java

這是一個javascript 的 interpreter是了解 web browser的好材料

/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Rhino code, released
 * May 6, 1999.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1997-1999
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Norris Boyd
 *   Roshan James
 *   Roger Lawrence
 *   Mike McCabe
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License Version 2 or later (the "GPL"), in which
 * case the provisions of the GPL are applicable instead of those above. If
 * you wish to allow use of your version of this file only under the terms of
 * the GPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replacing
 * them with the notice and other provisions required by the GPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the GPL.
 *
 * ***** END LICENSE BLOCK ***** */

package org.mozilla.javascript;

import java.util.Map;
import java.util.LinkedHashMap;
import java.util.Iterator;
import java.util.Collections;

/**
 * This class implements the root of the intermediate representation.
 *
 * @author Norris Boyd
 * @author Mike McCabe
 */

public class Node
{
    public static final int
        FUNCTION_PROP      =  1,
        LOCAL_PROP         =  2,
        LOCAL_BLOCK_PROP   =  3,
        REGEXP_PROP        =  4,
        CASEARRAY_PROP     =  5,
    /*
        the following properties are defined and manipulated by the
        optimizer -
        TARGETBLOCK_PROP - the block referenced by a branch node
        VARIABLE_PROP - the variable referenced by a BIND or NAME node
        ISNUMBER_PROP - this node generates code on Number children and
                        delivers a Number result (as opposed to Objects)
        DIRECTCALL_PROP - this call node should emit code to test the function
                          object against the known class and call diret if it
                          matches.
    */

        TARGETBLOCK_PROP   =  6,
        VARIABLE_PROP      =  7,
        ISNUMBER_PROP      =  8,
        DIRECTCALL_PROP    =  9,
        SPECIALCALL_PROP   = 10,
        SKIP_INDEXES_PROP  = 11, // array of skipped indexes of array literal
        OBJECT_IDS_PROP    = 12, // array of properties for object literal
        INCRDECR_PROP      = 13, // pre or post type of increment/decerement
        CATCH_SCOPE_PROP   = 14, // index of catch scope block in catch
        LABEL_ID_PROP      = 15, // label id: code generation uses it
        MEMBER_TYPE_PROP   = 16, // type of element access operation
        NAME_PROP          = 17, // property name
        CONTROL_BLOCK_PROP = 18, // flags a control block that can drop off
        PARENTHESIZED_PROP = 19, // expression is parenthesized
        GENERATOR_END_PROP = 20,
        DESTRUCTURING_ARRAY_LENGTH = 21,
        DESTRUCTURING_NAMES= 22,
        LAST_PROP          = 22;

    // values of ISNUMBER_PROP to specify
    // which of the children are Number types
    public static final int
        BOTH = 0,
        LEFT = 1,
        RIGHT = 2;

    public static final int    // values for SPECIALCALL_PROP
        NON_SPECIALCALL  = 0,
        SPECIALCALL_EVAL = 1,
        SPECIALCALL_WITH = 2;

    public static final int   // flags for INCRDECR_PROP
        DECR_FLAG = 0x1,
        POST_FLAG = 0x2;

    public static final int   // flags for MEMBER_TYPE_PROP
        PROPERTY_FLAG    = 0x1, // property access: element is valid name
        ATTRIBUTE_FLAG   = 0x2, // x.@y or x..@y
        DESCENDANTS_FLAG = 0x4; // x..y or x..@i

    private static class NumberNode extends Node
    {
        NumberNode(double number)
        {
            super(Token.NUMBER);
            this.number = number;
        }

        double number;
    }

    private static class StringNode extends Node
    {
        StringNode(int type, String str) {
            super(type);
            this.str = str;
        }

        String str;
        Node.Scope scope;
    }

    public static class Jump extends Node
    {
        public Jump(int type)
        {
            super(type);
        }

        Jump(int type, int lineno)
        {
            super(type, lineno);
        }

        Jump(int type, Node child)
        {
            super(type, child);
        }

        Jump(int type, Node child, int lineno)
        {
            super(type, child, lineno);
        }

        public final Jump getJumpStatement()
        {
            if (!(type == Token.BREAK || type == Token.CONTINUE)) Kit.codeBug();
            return jumpNode;
        }

        public final void setJumpStatement(Jump jumpStatement)
        {
            if (!(type == Token.BREAK || type == Token.CONTINUE)) Kit.codeBug();
            if (jumpStatement == null) Kit.codeBug();
            if (this.jumpNode != null) Kit.codeBug(); //only once
            this.jumpNode = jumpStatement;
        }

        public final Node getDefault()
        {
            if (!(type == Token.SWITCH)) Kit.codeBug();
            return target2;
        }

        public final void setDefault(Node defaultTarget)
        {
            if (!(type == Token.SWITCH)) Kit.codeBug();
            if (defaultTarget.type != Token.TARGET) Kit.codeBug();
            if (target2 != null) Kit.codeBug(); //only once
            target2 = defaultTarget;
        }

        public final Node getFinally()
        {
            if (!(type == Token.TRY)) Kit.codeBug();
            return target2;
        }

        public final void setFinally(Node finallyTarget)
        {
            if (!(type == Token.TRY)) Kit.codeBug();
            if (finallyTarget.type != Token.TARGET) Kit.codeBug();
            if (target2 != null) Kit.codeBug(); //only once
            target2 = finallyTarget;
        }

        public final Jump getLoop()
        {
            if (!(type == Token.LABEL)) Kit.codeBug();
            return jumpNode;
        }

        public final void setLoop(Jump loop)
        {
            if (!(type == Token.LABEL)) Kit.codeBug();
            if (loop == null) Kit.codeBug();
            if (jumpNode != null) Kit.codeBug(); //only once
            jumpNode = loop;
        }

        public final Node getContinue()
        {
            if (type != Token.LOOP) Kit.codeBug();
            return target2;
        }

        public final void setContinue(Node continueTarget)
        {
            if (type != Token.LOOP) Kit.codeBug();
            if (continueTarget.type != Token.TARGET) Kit.codeBug();
            if (target2 != null) Kit.codeBug(); //only once
            target2 = continueTarget;
        }

        public Node target;
        private Node target2;
        private Jump jumpNode;
    }
    
    static class Symbol {
        Symbol(int declType, String name) {
            this.declType = declType;
            this.name = name;
            this.index = -1;
        }
        /**
         * One of Token.FUNCTION, Token.LP (for parameters), Token.VAR, 
         * Token.LET, or Token.CONST
         */
        int declType;
        int index;
        String name;
        Node.Scope containingTable;
    }
    
    static class Scope extends Jump {
        public Scope(int nodeType) {
            super(nodeType);
        }
        
        public Scope(int nodeType, int lineno) {
            super(nodeType, lineno);
        }
        
        public Scope(int nodeType, Node n, int lineno) {
            super(nodeType, n, lineno);
        }
        
        /*
         * Creates a new scope node, moving symbol table information
         * from "scope" to the new node, and making "scope" a nested
         * scope contained by the new node.
         * Useful for injecting a new scope in a scope chain.
         */
        public static Scope splitScope(Scope scope) {
            Scope result = new Scope(scope.getType());
            result.symbolTable = scope.symbolTable;
            scope.symbolTable = null;
            result.parent = scope.parent;
            scope.parent = result;
            result.top = scope.top;
            return result;
        }

        public static void joinScopes(Scope source, Scope dest) {
            source.ensureSymbolTable();
            dest.ensureSymbolTable();
            if (!Collections.disjoint(source.symbolTable.keySet(),
                                      dest.symbolTable.keySet()))
            {
                throw Kit.codeBug();
            }
            dest.symbolTable.putAll(source.symbolTable);
        }
        
        public void setParent(Scope parent) {
            this.parent = parent;
            this.top = parent == null ? (ScriptOrFnNode)this : parent.top;
        }
        
        public Scope getParentScope() {
            return parent;
        }
  
        public Scope getDefiningScope(String name) {
            for (Scope sn=this; sn != null; sn = sn.parent) {
                if (sn.symbolTable == null)
                    continue;
                if (sn.symbolTable.containsKey(name))
                    return sn;
            }
            return null;
        }
        
        public Symbol getSymbol(String name) {
            return symbolTable == null ? null : symbolTable.get(name);
        }
        
        public void putSymbol(String name, Symbol symbol) {
            ensureSymbolTable();
            symbolTable.put(name, symbol);
            symbol.containingTable = this;
            top.addSymbol(symbol);
        }
        
        public Map<String,Symbol> getSymbolTable() {
            return symbolTable;
        }
        
        private void ensureSymbolTable() {
            if (symbolTable == null) {
                symbolTable = new LinkedHashMap<String,Symbol>(5);
            }
        }
  
        // Use LinkedHashMap so that the iteration order is the insertion order
        protected LinkedHashMap<String,Symbol> symbolTable;
        private Scope parent;
        private ScriptOrFnNode top;
    }

    private static class PropListItem
    {
        PropListItem next;
        int type;
        int intValue;
        Object objectValue;
    }


    public Node(int nodeType) {
        type = nodeType;
    }

    public Node(int nodeType, Node child) {
        type = nodeType;
        first = last = child;
        child.next = null;
    }

    public Node(int nodeType, Node left, Node right) {
        type = nodeType;
        first = left;
        last = right;
        left.next = right;
        right.next = null;
    }

    public Node(int nodeType, Node left, Node mid, Node right) {
        type = nodeType;
        first = left;
        last = right;
        left.next = mid;
        mid.next = right;
        right.next = null;
    }

    public Node(int nodeType, int line) {
        type = nodeType;
        lineno = line;
    }

    public Node(int nodeType, Node child, int line) {
        this(nodeType, child);
        lineno = line;
    }

    public Node(int nodeType, Node left, Node right, int line) {
        this(nodeType, left, right);
        lineno = line;
    }

    public Node(int nodeType, Node left, Node mid, Node right, int line) {
        this(nodeType, left, mid, right);
        lineno = line;
    }

    public static Node newNumber(double number) {
        return new NumberNode(number);
    }

    public static Node newString(String str) {
        return new StringNode(Token.STRING, str);
    }

    public static Node newString(int type, String str) {
        return new StringNode(type, str);
    }

    public int getType() {
        return type;
    }

    public void setType(int type) {
        this.type = type;
    }

    public boolean hasChildren() {
        return first != null;
    }

    public Node getFirstChild() {
        return first;
    }

    public Node getLastChild() {
        return last;
    }

    public Node getNext() {
        return next;
    }

    public Node getChildBefore(Node child) {
        if (child == first)
            return null;
        Node n = first;
        while (n.next != child) {
            n = n.next;
            if (n == null)
                throw new RuntimeException("node is not a child");
        }
        return n;
    }

    public Node getLastSibling() {
        Node n = this;
        while (n.next != null) {
            n = n.next;
        }
        return n;
    }

    public void addChildToFront(Node child) {
        child.next = first;
        first = child;
        if (last == null) {
            last = child;
        }
    }

    public void addChildToBack(Node child) {
        child.next = null;
        if (last == null) {
            first = last = child;
            return;
        }
        last.next = child;
        last = child;
    }