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package com.oracle.truffle.llvm.runtime.pointer;

import com.oracle.truffle.api.CompilerDirectives.ValueType;
import com.oracle.truffle.api.interop.TruffleObject;
import com.oracle.truffle.llvm.runtime.interop.access.LLVMInteropType;
import com.oracle.truffle.llvm.runtime.nodes.api.LLVMNode;
import com.oracle.truffle.llvm.runtime.nodes.api.LLVMTypes;

Common base interface for all pointer representations. An LLVMPointer is either a LLVMNativePointer or a LLVMManagedPointer. Important: Java type checks or casts for the pointer interface type will not work because all interfaces are implemented by a single implementation class for efficiency reasons. Use the static methods isInstance and cast instead. All nodes that use specializations on pointer interfaces need to extend from LLVMNode, or at least use the LLVMTypes type system. /**
 * Common base interface for all pointer representations. An {@link LLVMPointer} is either a
 * {@link LLVMNativePointer} or a {@link LLVMManagedPointer}.
 *
 * Important: Java type checks or casts for the pointer interface type will not work because all
 * interfaces are implemented by a single implementation class for efficiency reasons. Use the
 * static methods {@link #isInstance} and {@link #cast} instead.
 *
 * All nodes that use specializations on pointer interfaces need to extend from {@link LLVMNode}, or
 * at least use the {@link LLVMTypes} type system.
 */
public interface LLVMPointer extends TruffleObject {

    
Check whether this pointer is null.
/**
     * Check whether this pointer is null.
     */
    boolean isNull();

    
Create an exact copy of this pointer. This method should be used whenever a pointer is read from or written to the Java heap, to help escape analysis. Note that LLVMPointer and its sub-interfaces are considered ValueType, so reference comparison with == is undefined. Therefore, depending on compiler optimizations, copy might not really create a new instance. /**
     * Create an exact copy of this pointer. This method should be used whenever a pointer is read
     * from or written to the Java heap, to help escape analysis.
     *
     * Note that {@link LLVMPointer} and its sub-interfaces are considered {@link ValueType}, so
     * reference comparison with {@code ==} is undefined. Therefore, depending on compiler
     * optimizations, {@link #copy} might not really create a new instance.
     */
    LLVMPointer copy();

    
Increment this pointer. The export type of the result pointer is reset to null. /**
     * Increment this pointer. The {@link #getExportType export type} of the result pointer is reset
     * to {@code null}.
     */
    LLVMPointer increment(long offset);

    
Get the LLVMInteropType of this pointer. This type is used to determine access semantics from other languages. /**
     * Get the {@link LLVMInteropType} of this pointer. This type is used to determine access
     * semantics from other languages.
     */
    LLVMInteropType getExportType();

    
Create a copy of this pointer with a new LLVMInteropType. /**
     * Create a copy of this pointer with a new {@link LLVMInteropType}.
     */
    LLVMPointer export(LLVMInteropType newType);

    
Check whether two pointers refer to the same target. For managed pointers, this will do a
shallow comparison. If both pointers point to the different managed objects that are wrappers
for the same underlying object, this will return false.
/**
     * Check whether two pointers refer to the same target. For managed pointers, this will do a
     * shallow comparison. If both pointers point to the different managed objects that are wrappers
     * for the same underlying object, this will return false.
     */
    boolean isSame(LLVMPointer other);

    
Deep equality comparison.
Deprecated:
Should not be used!/**
     * Deep equality comparison.
     *
     * @deprecated Should not be used!
     */
    @Override
    @Deprecated
    boolean equals(Object obj);

    
Check whether an object is a LLVMPointer. This method must be used instead of the regular Java instanceof operator. /**
     * Check whether an object is a {@link LLVMPointer}. This method must be used instead of the
     * regular Java {@code instanceof} operator.
     */
    static boolean isInstance(Object object) {
        return object instanceof LLVMPointerImpl;
    }

    
Cast an object to a LLVMPointer. This method must be used instead of the regular Java typecast operator. /**
     * Cast an object to a {@link LLVMPointer}. This method must be used instead of the regular Java
     * typecast operator.
     */
    static LLVMPointer cast(Object object) {
        return (LLVMPointerImpl) object;
    }
}