/*

 * Copyright 1994-2004 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.tools.java;

import sun.tools.tree.*;

import java.io.IOException;

import java.io.InputStream;

import java.util.Enumeration;

import java.util.Vector;

/**

 * This class is used to parse Java statements and expressions.

 * The result is a parse tree.<p>

 *

 * This class implements an operator precedence parser. Errors are

 * reported to the Environment object, if the error can't be

 * resolved immediately, a SyntaxError exception is thrown.<p>

 *

 * Error recovery is implemented by catching SyntaxError exceptions

 * and discarding input tokens until an input token is reached that

 * is possibly a legal continuation.<p>

 *

 * The parse tree that is constructed represents the input

 * exactly (no rewrites to simpler forms). This is important

 * if the resulting tree is to be used for code formatting in

 * a programming environment. Currently only documentation comments

 * are retained.<p>

 *

 * The parsing algorithm does NOT use any type information. Changes

 * in the type system do not affect the structure of the parse tree.

 * This restriction does introduce an ambiguity an expression of the

 * form: (e1) e2 is assumed to be a cast if e2 does not start with

 * an operator. That means that (a) - b is interpreted as subtract

 * b from a and not cast negative b to type a. However, if a is a

 * simple type (byte, int, ...) then it is assumed to be a cast.<p>

 *

 * WARNING: The contents of this source file are not part of any

 * supported API.  Code that depends on them does so at its own risk:

 * they are subject to change or removal without notice.

 *

 * @author      Arthur van Hoff

 */

public

class Parser extends Scanner implements ParserActions, Constants {

    /**

     * Create a parser

     */

    protected Parser(Environment env, InputStream in) throws IOException {

        super(env, in);

        this.scanner = this;

        this.actions = this;

    }

    /**

     * Create a parser, given a scanner.

     */

    protected Parser(Scanner scanner) throws IOException {

        super(scanner.env);

        this.scanner = scanner;

        ((Scanner)this).env = scanner.env;

        ((Scanner)this).token = scanner.token;

        ((Scanner)this).pos = scanner.pos;

        this.actions = this;

    }

    /**

     * Create a parser, given a scanner and the semantic callback.

     */

    public Parser(Scanner scanner, ParserActions actions) throws IOException {

        this(scanner);

        this.actions = actions;

    }

    /**

     * Usually <code>this.actions == (ParserActions)this</code>.

     * However, a delegate scanner can produce tokens for this parser,

     * in which case <code>(Scanner)this</code> is unused,

     * except for <code>this.token</code> and <code>this.pos</code>

     * instance variables which are filled from the real scanner

     * by <code>this.scan()</code> and the constructor.

     */

    ParserActions actions;

    // Note:  The duplication of methods allows pre-1.1 classes to

    // be binary compatible with the new version of the parser,

    // which now passes IdentifierTokens to the semantics phase,

    // rather than just Identifiers.  This change is necessary,

    // since the parser is no longer responsible for managing the

    // resolution of type names.  (That caused the "Vector" bug.)

    //

    // In a future release, the old "plain-Identifier" methods will

    // go away, and the corresponding "IdentifierToken" methods

    // may become abstract.

    /**

     * package declaration

     * @deprecated

     */

    @Deprecated

    public void packageDeclaration(long off, IdentifierToken nm) {

        // By default, call the deprecated version.

        // Any application must override one of the packageDeclaration methods.

        packageDeclaration(off, nm.id);

    }

    /**

     * @deprecated

     */

    @Deprecated

    protected void packageDeclaration(long off, Identifier nm) {

        throw new RuntimeException("beginClass method is abstract");

    }

    /**

     * import class

     * @deprecated

     */

    @Deprecated

    public void importClass(long off, IdentifierToken nm) {

        // By default, call the deprecated version.

        // Any application must override one of the packageDeclaration methods.

        importClass(off, nm.id);

    }

    /**

     * @deprecated Use the version with the IdentifierToken arguments.

     */

    @Deprecated

    protected void importClass(long off, Identifier nm) {

        throw new RuntimeException("importClass method is abstract");

    }

    /**

     * import package

     * @deprecated

     */

    @Deprecated

    public void importPackage(long off, IdentifierToken nm) {

        // By default, call the deprecated version.

        // Any application must override one of the importPackage methods.

        importPackage(off, nm.id);

    }

    /**

     * @deprecated Use the version with the IdentifierToken arguments.

     */

    @Deprecated

    protected void importPackage(long off, Identifier nm) {

        throw new RuntimeException("importPackage method is abstract");

    }

    /**

     * Define class

     * @deprecated

     */

    @Deprecated

    public ClassDefinition beginClass(long off, String doc,

                                      int mod, IdentifierToken nm,

                                      IdentifierToken sup,

                                      IdentifierToken impl[]) {

        // By default, call the deprecated version.

        // Any application must override one of the beginClass methods.

        Identifier supId = (sup == null) ? null : sup.id;

        Identifier implIds[] = null;

        if (impl != null) {

            implIds = new Identifier[impl.length];

            for (int i = 0; i < impl.length; i++) {

                implIds[i] = impl[i].id;

            }

        }

        beginClass(off, doc, mod, nm.id, supId, implIds);

        return getCurrentClass();

    }

    /**

     * @deprecated Use the version with the IdentifierToken arguments.

     */

    @Deprecated

    protected void beginClass(long off, String doc, int mod, Identifier nm,

                              Identifier sup, Identifier impl[]) {

        throw new RuntimeException("beginClass method is abstract");

    }

    /**

     * Report the current class under construction.

     * By default, it's a no-op which returns null.

     * It may only be called before the corresponding endClass().

     */

    protected ClassDefinition getCurrentClass() {

        return null;

    }

    /**

     * End class

     * @deprecated

     */

    @Deprecated

    public void endClass(long off, ClassDefinition c) {

        // By default, call the deprecated version.

        // Any application must override one of the beginClass methods.

        endClass(off, c.getName().getFlatName().getName());

    }

    /**

     * @deprecated Use the version with the IdentifierToken arguments.

     */

    @Deprecated

    protected void endClass(long off, Identifier nm) {

        throw new RuntimeException("endClass method is abstract");

    }

    /**

     * Define a field

     * @deprecated

     */

    @Deprecated

    public void defineField(long where, ClassDefinition c,

                            String doc, int mod, Type t,

                            IdentifierToken nm, IdentifierToken args[],

                            IdentifierToken exp[], Node val) {

        // By default, call the deprecated version.

        // Any application must override one of the defineField methods.

        Identifier argIds[] = null;

        Identifier expIds[] = null;

        if (args != null) {

            argIds = new Identifier[args.length];

            for (int i = 0; i < args.length; i++) {

                argIds[i] = args[i].id;

            }

        }

        if (exp != null) {

            expIds = new Identifier[exp.length];

            for (int i = 0; i < exp.length; i++) {

                expIds[i] = exp[i].id;

            }

        }

        defineField(where, doc, mod, t, nm.id, argIds, expIds, val);

    }

    /**

     * @deprecated Use the version with the IdentifierToken arguments.

     */

    @Deprecated

    protected void defineField(long where, String doc, int mod, Type t,

                               Identifier nm, Identifier args[],

                               Identifier exp[], Node val) {

        throw new RuntimeException("defineField method is abstract");

    }

    /*

     * A growable array of nodes. It is used as a growable

     * buffer to hold argument lists and expression lists.

     * I'm not using Vector to make it more efficient.

     */

    private Node args[] = new Node[32];

    protected int argIndex = 0;

    protected final void addArgument(Node n) {

        if (argIndex == args.length) {

            Node newArgs[] = new Node[args.length * 2];

            System.arraycopy(args, 0, newArgs, 0, args.length);

            args = newArgs;

        }

        args[argIndex++] = n;

    }

    protected final Expression exprArgs(int index)[] {

        Expression e[] = new Expression[argIndex - index];

        System.arraycopy(args, index, e, 0, argIndex - index);

        argIndex = index;

        return e;

    }

    protected final Statement statArgs(int index)[] {

        Statement s[] = new Statement[argIndex - index];

        System.arraycopy(args, index, s, 0, argIndex - index);

        argIndex = index;

        return s;

    }

    /**

     * Expect a token, return its value, scan the next token or

     * throw an exception.

     */

    protected void expect(int t) throws SyntaxError, IOException {

        if (token != t) {

            switch (t) {

              case IDENT:

                env.error(scanner.prevPos, "identifier.expected");

                break;

              default:

                env.error(scanner.prevPos, "token.expected", opNames[t]);

                break;

            }

                throw new SyntaxError();

        }

        scan();

    }

    /**

     * Parse a type expression. Does not parse the []'s.

     */

    protected Expression parseTypeExpression() throws SyntaxError, IOException {

        switch (token) {

          case VOID:

            return new TypeExpression(scan(), Type.tVoid);

          case BOOLEAN:

            return new TypeExpression(scan(), Type.tBoolean);

          case BYTE:

            return new TypeExpression(scan(), Type.tByte);

          case CHAR:

            return new TypeExpression(scan(), Type.tChar);

          case SHORT:

            return new TypeExpression(scan(), Type.tShort);

          case INT:

            return new TypeExpression(scan(), Type.tInt);

          case LONG:

            return new TypeExpression(scan(), Type.tLong);

          case FLOAT:

            return new TypeExpression(scan(), Type.tFloat);

          case DOUBLE:

            return new TypeExpression(scan(), Type.tDouble);

          case IDENT:

            Expression e = new IdentifierExpression(pos, scanner.idValue);

            scan();

            while (token == FIELD) {

                e = new FieldExpression(scan(), e, scanner.idValue);

                expect(IDENT);

            }

            return e;

        }

        env.error(pos, "type.expected");

        throw new SyntaxError();

    }

    /**

     * Parse a method invocation. Should be called when the current

     * then is the '(' of the argument list.

     */

    protected Expression parseMethodExpression(Expression e, Identifier id) throws SyntaxError, IOException {

       long p = scan();

       int i = argIndex;

       if (token != RPAREN) {

           addArgument(parseExpression());

           while (token == COMMA) {

               scan();

               addArgument(parseExpression());

           }

       }

       expect(RPAREN);

       return new MethodExpression(p, e, id, exprArgs(i));

    }

    /**

     * Parse a new instance expression.  Should be called when the current

     * token is the '(' of the argument list.

     */

    protected Expression parseNewInstanceExpression(long p, Expression outerArg, Expression type) throws SyntaxError, IOException {

        int i = argIndex;

        expect(LPAREN);

        if (token != RPAREN) {

            addArgument(parseExpression());

            while (token == COMMA) {

                scan();

                addArgument(parseExpression());

            }

        }

        expect(RPAREN);

        ClassDefinition body = null;

        if (token == LBRACE && !(type instanceof TypeExpression)) {

            long tp = pos;

            // x = new Type(arg) { subclass body ... }

            Identifier superName = FieldExpression.toIdentifier(type);

            if (superName == null) {

                env.error(type.getWhere(), "type.expected");

            }

            Vector ext = new Vector(1);

            Vector impl = new Vector(0);

            ext.addElement(new IdentifierToken(idNull));

            if (token == IMPLEMENTS || token == EXTENDS) {

                env.error(pos, "anonymous.extends");

                parseInheritance(ext, impl); // error recovery

            }

            body = parseClassBody(new IdentifierToken(tp, idNull),

                                  M_ANONYMOUS | M_LOCAL, EXPR, null,

                                  ext, impl, type.getWhere());

        }

        if (outerArg == null && body == null) {

            return new NewInstanceExpression(p, type, exprArgs(i));

        }

        return new NewInstanceExpression(p, type, exprArgs(i), outerArg, body);

    }

    /**

     * Parse a primary expression.

     */

    protected Expression parseTerm() throws SyntaxError, IOException {

        switch (token) {

          case CHARVAL: {

            char v = scanner.charValue;

            return new CharExpression(scan(), v);

          }

          case INTVAL: {

            int v = scanner.intValue;

            long q = scan();

            if (v < 0 && radix == 10) env.error(q, "overflow.int.dec");

            return new IntExpression(q, v);

          }

          case LONGVAL: {

            long v = scanner.longValue;

            long q = scan();

            if (v < 0 && radix == 10) env.error(q, "overflow.long.dec");

            return new LongExpression(q, v);

          }

          case FLOATVAL: {

            float v = scanner.floatValue;

            return new FloatExpression(scan(), v);

          }

          case DOUBLEVAL: {

            double v = scanner.doubleValue;

            return new DoubleExpression(scan(), v);

          }

          case STRINGVAL: {

            String v = scanner.stringValue;

            return new StringExpression(scan(), v);

          }

          case IDENT: {

            Identifier v = scanner.idValue;

            long p = scan();

            return (token == LPAREN) ?

                        parseMethodExpression(null, v) : new IdentifierExpression(p, v);

          }

          case TRUE:

            return new BooleanExpression(scan(), true);

          case FALSE:

            return new BooleanExpression(scan(), false);

          case NULL:

            return new NullExpression(scan());

          case THIS: {

            Expression e = new ThisExpression(scan());

            return (token == LPAREN) ? parseMethodExpression(e, idInit) : e;

          }

          case SUPER: {

            Expression e = new SuperExpression(scan());

            return (token == LPAREN) ? parseMethodExpression(e, idInit) : e;

          }

          case VOID:

          case BOOLEAN:

          case BYTE:

          case CHAR:

          case SHORT:

          case INT:

          case LONG:

          case FLOAT:

          case DOUBLE:

            return parseTypeExpression();

          case ADD: {

            long p = scan();

            switch (token) {

              case INTVAL: {

                int v = scanner.intValue;

                long q = scan();

                if (v < 0 && radix == 10) env.error(q, "overflow.int.dec");

                return new IntExpression(q, v);

              }

              case LONGVAL: {

                long v = scanner.longValue;

                long q = scan();

                if (v < 0 && radix == 10) env.error(q, "overflow.long.dec");

                return new LongExpression(q, v);

              }

              case FLOATVAL: {

                float v = scanner.floatValue;

                return new FloatExpression(scan(), v);

              }

              case DOUBLEVAL: {

                double v = scanner.doubleValue;

                return new DoubleExpression(scan(), v);

              }

            }

            return new PositiveExpression(p, parseTerm());

          }

          case SUB: {

            long p = scan();

            switch (token) {

              case INTVAL: {

                int v = -scanner.intValue;

                return new IntExpression(scan(), v);

              }

              case LONGVAL: {

                long v = -scanner.longValue;

                return new LongExpression(scan(), v);

              }

              case FLOATVAL: {

                float v = -scanner.floatValue;

                return new FloatExpression(scan(), v);

              }

              case DOUBLEVAL: {

                double v = -scanner.doubleValue;

                return new DoubleExpression(scan(), v);

              }

            }

            return new NegativeExpression(p, parseTerm());

          }

          case NOT:

            return new NotExpression(scan(), parseTerm());

          case BITNOT: