/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2007 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package alterrs.asm.util;

import alterrs.asm.signature.SignatureVisitor;

/**
 * A {@link alterrs.asm.signature.SignatureVisitor} that checks that its methods
 * are properly used.
 * 
 * @author Eric Bruneton
 */
public class CheckSignatureAdapter implements SignatureVisitor {

	/**
	 * Type to be used to check class signatures. See
	 * {@link #CheckSignatureAdapter(int, SignatureVisitor)
	 * CheckSignatureAdapter}.
	 */
	public static final int CLASS_SIGNATURE = 0;

	/**
	 * Type to be used to check method signatures. See
	 * {@link #CheckSignatureAdapter(int, SignatureVisitor)
	 * CheckSignatureAdapter}.
	 */
	public static final int METHOD_SIGNATURE = 1;

	/**
	 * Type to be used to check type signatures.See
	 * {@link #CheckSignatureAdapter(int, SignatureVisitor)
	 * CheckSignatureAdapter}.
	 */
	public static final int TYPE_SIGNATURE = 2;

	private static final int EMPTY = 1;

	private static final int FORMAL = 2;

	private static final int BOUND = 4;

	private static final int SUPER = 8;

	private static final int PARAM = 16;

	private static final int RETURN = 32;

	private static final int SIMPLE_TYPE = 64;

	private static final int CLASS_TYPE = 128;

	private static final int END = 256;

	/**
	 * Type of the signature to be checked.
	 */
	private final int type;

	/**
	 * State of the automaton used to check the order of method calls.
	 */
	private int state;

	/**
	 * <tt>true</tt> if the checked type signature can be 'V'.
	 */
	private boolean canBeVoid;

	/**
	 * The visitor to which this adapter must delegate calls. May be
	 * <tt>null</tt>.
	 */
	private final SignatureVisitor sv;

	/**
	 * Creates a new {@link CheckSignatureAdapter} object.
	 * 
	 * @param type
	 *            the type of signature to be checked. See
	 *            {@link #CLASS_SIGNATURE}, {@link #METHOD_SIGNATURE} and
	 *            {@link #TYPE_SIGNATURE}.
	 * @param sv
	 *            the visitor to which this adapter must delegate calls. May be
	 *            <tt>null</tt>.
	 */
	public CheckSignatureAdapter(final int type, final SignatureVisitor sv) {
		this.type = type;
		this.state = EMPTY;
		this.sv = sv;
	}

	// class and method signatures

	public void visitFormalTypeParameter(final String name) {
		if (type == TYPE_SIGNATURE
				|| (state != EMPTY && state != FORMAL && state != BOUND)) {
			throw new IllegalStateException();
		}
		CheckMethodAdapter.checkIdentifier(name, "formal type parameter");
		state = FORMAL;
		if (sv != null) {
			sv.visitFormalTypeParameter(name);
		}
	}

	public SignatureVisitor visitClassBound() {
		if (state != FORMAL) {
			throw new IllegalStateException();
		}
		state = BOUND;
		SignatureVisitor v = sv == null ? null : sv.visitClassBound();
		return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
	}

	public SignatureVisitor visitInterfaceBound() {
		if (state != FORMAL && state != BOUND) {
			throw new IllegalArgumentException();
		}
		SignatureVisitor v = sv == null ? null : sv.visitInterfaceBound();
		return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
	}

	// class signatures

	public SignatureVisitor visitSuperclass() {
		if (type != CLASS_SIGNATURE || (state & (EMPTY | FORMAL | BOUND)) == 0) {
			throw new IllegalArgumentException();
		}
		state = SUPER;
		SignatureVisitor v = sv == null ? null : sv.visitSuperclass();
		return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
	}

	public SignatureVisitor visitInterface() {
		if (state != SUPER) {
			throw new IllegalStateException();
		}
		SignatureVisitor v = sv == null ? null : sv.visitInterface();
		return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
	}

	// method signatures

	public SignatureVisitor visitParameterType() {
		if (type != METHOD_SIGNATURE
				|| (state & (EMPTY | FORMAL | BOUND | PARAM)) == 0) {
			throw new IllegalArgumentException();
		}
		state = PARAM;
		SignatureVisitor v = sv == null ? null : sv.visitParameterType();
		return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
	}

	public SignatureVisitor visitReturnType() {
		if (type != METHOD_SIGNATURE
				|| (state & (EMPTY | FORMAL | BOUND | PARAM)) == 0) {
			throw new IllegalArgumentException();
		}
		state = RETURN;
		SignatureVisitor v = sv == null ? null : sv.visitReturnType();
		CheckSignatureAdapter cv = new CheckSignatureAdapter(TYPE_SIGNATURE, v);
		cv.canBeVoid = true;
		return cv;
	}

	public SignatureVisitor visitExceptionType() {
		if (state != RETURN) {
			throw new IllegalStateException();
		}
		SignatureVisitor v = sv == null ? null : sv.visitExceptionType();
		return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
	}

	// type signatures

	public void visitBaseType(final char descriptor) {
		if (type != TYPE_SIGNATURE || state != EMPTY) {
			throw new IllegalStateException();
		}
		if (descriptor == 'V') {
			if (!canBeVoid) {
				throw new IllegalArgumentException();
			}
		} else {
			if ("ZCBSIFJD".indexOf(descriptor) == -1) {
				throw new IllegalArgumentException();
			}
		}
		state = SIMPLE_TYPE;
		if (sv != null) {
			sv.visitBaseType(descriptor);
		}
	}

	public void visitTypeVariable(final String name) {
		if (type != TYPE_SIGNATURE || state != EMPTY) {
			throw new IllegalStateException();
		}
		CheckMethodAdapter.checkIdentifier(name, "type variable");
		state = SIMPLE_TYPE;
		if (sv != null) {
			sv.visitTypeVariable(name);
		}
	}

	public SignatureVisitor visitArrayType() {
		if (type != TYPE_SIGNATURE || state != EMPTY) {
			throw new IllegalStateException();
		}
		state = SIMPLE_TYPE;
		SignatureVisitor v = sv == null ? null : sv.visitArrayType();
		return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
	}

	public void visitClassType(final String name) {
		if (type != TYPE_SIGNATURE || state != EMPTY) {
			throw new IllegalStateException();
		}
		CheckMethodAdapter.checkInternalName(name, "class name");
		state = CLASS_TYPE;
		if (sv != null) {
			sv.visitClassType(name);
		}
	}

	public void visitInnerClassType(final String name) {
		if (state != CLASS_TYPE) {
			throw new IllegalStateException();
		}
		CheckMethodAdapter.checkIdentifier(name, "inner class name");
		if (sv != null) {
			sv.visitInnerClassType(name);
		}
	}

	public void visitTypeArgument() {
		if (state != CLASS_TYPE) {
			throw new IllegalStateException();
		}
		if (sv != null) {
			sv.visitTypeArgument();
		}
	}

	public SignatureVisitor visitTypeArgument(final char wildcard) {
		if (state != CLASS_TYPE) {
			throw new IllegalStateException();
		}
		if ("+-=".indexOf(wildcard) == -1) {
			throw new IllegalArgumentException();
		}
		SignatureVisitor v = sv == null ? null : sv.visitTypeArgument(wildcard);
		return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
	}

	public void visitEnd() {
		if (state != CLASS_TYPE) {
			throw new IllegalStateException();
		}
		state = END;
		if (sv != null) {
			sv.visitEnd();
		}
	}
}
