/***
 * 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.tree.analysis;

import java.util.List;

import alterrs.asm.Opcodes;
import alterrs.asm.Type;
import alterrs.asm.tree.AbstractInsnNode;
import alterrs.asm.tree.FieldInsnNode;
import alterrs.asm.tree.MethodInsnNode;

/**
 * An extended {@link BasicInterpreter} that checks that bytecode instructions
 * are correctly used.
 * 
 * @author Eric Bruneton
 * @author Bing Ran
 */
public class BasicVerifier extends BasicInterpreter {

	public Value copyOperation(final AbstractInsnNode insn, final Value value)
			throws AnalyzerException {
		Value expected;
		switch (insn.getOpcode()) {
		case Opcodes.ILOAD:
		case Opcodes.ISTORE:
			expected = BasicValue.INT_VALUE;
			break;
		case Opcodes.FLOAD:
		case Opcodes.FSTORE:
			expected = BasicValue.FLOAT_VALUE;
			break;
		case Opcodes.LLOAD:
		case Opcodes.LSTORE:
			expected = BasicValue.LONG_VALUE;
			break;
		case Opcodes.DLOAD:
		case Opcodes.DSTORE:
			expected = BasicValue.DOUBLE_VALUE;
			break;
		case Opcodes.ALOAD:
			if (!((BasicValue) value).isReference()) {
				throw new AnalyzerException(insn, null, "an object reference",
						value);
			}
			return value;
		case Opcodes.ASTORE:
			if (!((BasicValue) value).isReference()
					&& !BasicValue.RETURNADDRESS_VALUE.equals(value)) {
				throw new AnalyzerException(insn, null,
						"an object reference or a return address", value);
			}
			return value;
		default:
			return value;
		}
		if (!expected.equals(value)) {
			throw new AnalyzerException(insn, null, expected, value);
		}
		return value;
	}

	public Value unaryOperation(final AbstractInsnNode insn, final Value value)
			throws AnalyzerException {
		Value expected;
		switch (insn.getOpcode()) {
		case Opcodes.INEG:
		case Opcodes.IINC:
		case Opcodes.I2F:
		case Opcodes.I2L:
		case Opcodes.I2D:
		case Opcodes.I2B:
		case Opcodes.I2C:
		case Opcodes.I2S:
		case Opcodes.IFEQ:
		case Opcodes.IFNE:
		case Opcodes.IFLT:
		case Opcodes.IFGE:
		case Opcodes.IFGT:
		case Opcodes.IFLE:
		case Opcodes.TABLESWITCH:
		case Opcodes.LOOKUPSWITCH:
		case Opcodes.IRETURN:
		case Opcodes.NEWARRAY:
		case Opcodes.ANEWARRAY:
			expected = BasicValue.INT_VALUE;
			break;
		case Opcodes.FNEG:
		case Opcodes.F2I:
		case Opcodes.F2L:
		case Opcodes.F2D:
		case Opcodes.FRETURN:
			expected = BasicValue.FLOAT_VALUE;
			break;
		case Opcodes.LNEG:
		case Opcodes.L2I:
		case Opcodes.L2F:
		case Opcodes.L2D:
		case Opcodes.LRETURN:
			expected = BasicValue.LONG_VALUE;
			break;
		case Opcodes.DNEG:
		case Opcodes.D2I:
		case Opcodes.D2F:
		case Opcodes.D2L:
		case Opcodes.DRETURN:
			expected = BasicValue.DOUBLE_VALUE;
			break;
		case Opcodes.GETFIELD:
			expected = newValue(Type
					.getObjectType(((FieldInsnNode) insn).owner));
			break;
		case Opcodes.CHECKCAST:
			if (!((BasicValue) value).isReference()) {
				throw new AnalyzerException(insn, null, "an object reference",
						value);
			}
			return super.unaryOperation(insn, value);
		case Opcodes.ARRAYLENGTH:
			if (!isArrayValue(value)) {
				throw new AnalyzerException(insn, null, "an array reference",
						value);
			}
			return super.unaryOperation(insn, value);
		case Opcodes.ARETURN:
		case Opcodes.ATHROW:
		case Opcodes.INSTANCEOF:
		case Opcodes.MONITORENTER:
		case Opcodes.MONITOREXIT:
		case Opcodes.IFNULL:
		case Opcodes.IFNONNULL:
			if (!((BasicValue) value).isReference()) {
				throw new AnalyzerException(insn, null, "an object reference",
						value);
			}
			return super.unaryOperation(insn, value);
		case Opcodes.PUTSTATIC:
			expected = newValue(Type.getType(((FieldInsnNode) insn).desc));
			break;
		default:
			throw new Error("Internal error.");
		}
		if (!isSubTypeOf(value, expected)) {
			throw new AnalyzerException(insn, null, expected, value);
		}
		return super.unaryOperation(insn, value);
	}

	public Value binaryOperation(final AbstractInsnNode insn,
			final Value value1, final Value value2) throws AnalyzerException {
		Value expected1;
		Value expected2;
		switch (insn.getOpcode()) {
		case Opcodes.IALOAD:
			expected1 = newValue(Type.getType("[I"));
			expected2 = BasicValue.INT_VALUE;
			break;
		case Opcodes.BALOAD:
			if (isSubTypeOf(value1, newValue(Type.getType("[Z")))) {
				expected1 = newValue(Type.getType("[Z"));
			} else {
				expected1 = newValue(Type.getType("[B"));
			}
			expected2 = BasicValue.INT_VALUE;
			break;
		case Opcodes.CALOAD:
			expected1 = newValue(Type.getType("[C"));
			expected2 = BasicValue.INT_VALUE;
			break;
		case Opcodes.SALOAD:
			expected1 = newValue(Type.getType("[S"));
			expected2 = BasicValue.INT_VALUE;
			break;
		case Opcodes.LALOAD:
			expected1 = newValue(Type.getType("[J"));
			expected2 = BasicValue.INT_VALUE;
			break;
		case Opcodes.FALOAD:
			expected1 = newValue(Type.getType("[F"));
			expected2 = BasicValue.INT_VALUE;
			break;
		case Opcodes.DALOAD:
			expected1 = newValue(Type.getType("[D"));
			expected2 = BasicValue.INT_VALUE;
			break;
		case Opcodes.AALOAD:
			expected1 = newValue(Type.getType("[Ljava/lang/Object;"));
			expected2 = BasicValue.INT_VALUE;
			break;
		case Opcodes.IADD:
		case Opcodes.ISUB:
		case Opcodes.IMUL:
		case Opcodes.IDIV:
		case Opcodes.IREM:
		case Opcodes.ISHL:
		case Opcodes.ISHR:
		case Opcodes.IUSHR:
		case Opcodes.IAND:
		case Opcodes.IOR:
		case Opcodes.IXOR:
		case Opcodes.IF_ICMPEQ:
		case Opcodes.IF_ICMPNE:
		case Opcodes.IF_ICMPLT:
		case Opcodes.IF_ICMPGE:
		case Opcodes.IF_ICMPGT:
		case Opcodes.IF_ICMPLE:
			expected1 = BasicValue.INT_VALUE;
			expected2 = BasicValue.INT_VALUE;
			break;
		case Opcodes.FADD:
		case Opcodes.FSUB:
		case Opcodes.FMUL:
		case Opcodes.FDIV:
		case Opcodes.FREM:
		case Opcodes.FCMPL:
		case Opcodes.FCMPG:
			expected1 = BasicValue.FLOAT_VALUE;
			expected2 = BasicValue.FLOAT_VALUE;
			break;
		case Opcodes.LADD:
		case Opcodes.LSUB:
		case Opcodes.LMUL:
		case Opcodes.LDIV:
		case Opcodes.LREM:
		case Opcodes.LAND:
		case Opcodes.LOR:
		case Opcodes.LXOR:
		case Opcodes.LCMP:
			expected1 = BasicValue.LONG_VALUE;
			expected2 = BasicValue.LONG_VALUE;
			break;
		case Opcodes.LSHL:
		case Opcodes.LSHR:
		case Opcodes.LUSHR:
			expected1 = BasicValue.LONG_VALUE;
			expected2 = BasicValue.INT_VALUE;
			break;
		case Opcodes.DADD:
		case Opcodes.DSUB:
		case Opcodes.DMUL:
		case Opcodes.DDIV:
		case Opcodes.DREM:
		case Opcodes.DCMPL:
		case Opcodes.DCMPG:
			expected1 = BasicValue.DOUBLE_VALUE;
			expected2 = BasicValue.DOUBLE_VALUE;
			break;
		case Opcodes.IF_ACMPEQ:
		case Opcodes.IF_ACMPNE:
			expected1 = BasicValue.REFERENCE_VALUE;
			expected2 = BasicValue.REFERENCE_VALUE;
			break;
		case Opcodes.PUTFIELD:
			FieldInsnNode fin = (FieldInsnNode) insn;
			expected1 = newValue(Type.getObjectType(fin.owner));
			expected2 = newValue(Type.getType(fin.desc));
			break;
		default:
			throw new Error("Internal error.");
		}
		if (!isSubTypeOf(value1, expected1)) {
			throw new AnalyzerException(insn, "First argument", expected1,
					value1);
		} else if (!isSubTypeOf(value2, expected2)) {
			throw new AnalyzerException(insn, "Second argument", expected2,
					value2);
		}
		if (insn.getOpcode() == Opcodes.AALOAD) {
			return getElementValue(value1);
		} else {
			return super.binaryOperation(insn, value1, value2);
		}
	}

	public Value ternaryOperation(final AbstractInsnNode insn,
			final Value value1, final Value value2, final Value value3)
			throws AnalyzerException {
		Value expected1;
		Value expected3;
		switch (insn.getOpcode()) {
		case Opcodes.IASTORE:
			expected1 = newValue(Type.getType("[I"));
			expected3 = BasicValue.INT_VALUE;
			break;
		case Opcodes.BASTORE:
			if (isSubTypeOf(value1, newValue(Type.getType("[Z")))) {
				expected1 = newValue(Type.getType("[Z"));
			} else {
				expected1 = newValue(Type.getType("[B"));
			}
			expected3 = BasicValue.INT_VALUE;
			break;
		case Opcodes.CASTORE:
			expected1 = newValue(Type.getType("[C"));
			expected3 = BasicValue.INT_VALUE;
			break;
		case Opcodes.SASTORE:
			expected1 = newValue(Type.getType("[S"));
			expected3 = BasicValue.INT_VALUE;
			break;
		case Opcodes.LASTORE:
			expected1 = newValue(Type.getType("[J"));
			expected3 = BasicValue.LONG_VALUE;
			break;
		case Opcodes.FASTORE:
			expected1 = newValue(Type.getType("[F"));
			expected3 = BasicValue.FLOAT_VALUE;
			break;
		case Opcodes.DASTORE:
			expected1 = newValue(Type.getType("[D"));
			expected3 = BasicValue.DOUBLE_VALUE;
			break;
		case Opcodes.AASTORE:
			expected1 = value1;
			expected3 = BasicValue.REFERENCE_VALUE;
			break;
		default:
			throw new Error("Internal error.");
		}
		if (!isSubTypeOf(value1, expected1)) {
			throw new AnalyzerException(insn, "First argument", "a "
					+ expected1 + " array reference", value1);
		} else if (!BasicValue.INT_VALUE.equals(value2)) {
			throw new AnalyzerException(insn, "Second argument",
					BasicValue.INT_VALUE, value2);
		} else if (!isSubTypeOf(value3, expected3)) {
			throw new AnalyzerException(insn, "Third argument", expected3,
					value3);
		}
		return null;
	}

	public Value naryOperation(final AbstractInsnNode insn, final List values)
			throws AnalyzerException {
		int opcode = insn.getOpcode();
		if (opcode == Opcodes.MULTIANEWARRAY) {
			for (int i = 0; i < values.size(); ++i) {
				if (!BasicValue.INT_VALUE.equals(values.get(i))) {
					throw new AnalyzerException(insn, null,
							BasicValue.INT_VALUE, (Value) values.get(i));
				}
			}
		} else {
			int i = 0;
			int j = 0;
			if (opcode != Opcodes.INVOKESTATIC
					&& opcode != Opcodes.INVOKEDYNAMIC) {
				Type owner = Type.getObjectType(((MethodInsnNode) insn).owner);
				if (!isSubTypeOf((Value) values.get(i++), newValue(owner))) {
					throw new AnalyzerException(insn, "Method owner",
							newValue(owner), (Value) values.get(0));
				}
			}
			Type[] args = Type.getArgumentTypes(((MethodInsnNode) insn).desc);
			while (i < values.size()) {
				Value expected = newValue(args[j++]);
				Value encountered = (Value) values.get(i++);
				if (!isSubTypeOf(encountered, expected)) {
					throw new AnalyzerException(insn, "Argument " + j,
							expected, encountered);
				}
			}
		}
		return super.naryOperation(insn, values);
	}

	public void returnOperation(final AbstractInsnNode insn, final Value value,
			final Value expected) throws AnalyzerException {
		if (!isSubTypeOf(value, expected)) {
			throw new AnalyzerException(insn, "Incompatible return type",
					expected, value);
		}
	}

	protected boolean isArrayValue(final Value value) {
		return ((BasicValue) value).isReference();
	}

	protected Value getElementValue(final Value objectArrayValue)
			throws AnalyzerException {
		return BasicValue.REFERENCE_VALUE;
	}

	protected boolean isSubTypeOf(final Value value, final Value expected) {
		return value.equals(expected);
	}
}
