InstrumentableFactory.java

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package com.oracle.truffle.api.instrumentation;

import com.oracle.truffle.api.nodes.Node;

/**
 * Factory for creating <em>wrapper nodes</em>. The instrumentation framework inserts a wrapper
 * between an {@link Instrumentable} guest language node (called the <em>delegate</em>) and its
 * parent for the purpose of interposing on execution events at the delegate and reporting those
 * events to the instrumentation framework.
 * </p>
 * <p>
 * Wrapper implementations can be generated automatically: see the {@link Instrumentable}
 * annotation.
 *
 * @param <T> the type of delegate node this factory operates on
 * @since 0.12
 */
public interface InstrumentableFactory<T extends Node> {

    /**
     * Returns a new, never adopted, unshared {@link WrapperNode wrapper} node implementation for a
     * particular {@link Instrumentable} node of the guest language AST called its <em>delegate</em>
     * . The returned wrapper implementation must extend the same type that is annotated with
     * {@link Instrumentable}.
     * </p>
     * <p>
     * A wrapper forwards the following events concerning the delegate to the given {@link ProbeNode
     * probe} for propagation through the instrumentation framework, e.g. to
     * {@linkplain ExecutionEventListener event listeners} bound to this guest language program
     * location:
     * <ul>
     * <li>{@linkplain ProbeNode#onEnter(com.oracle.truffle.api.frame.VirtualFrame) onEnter(Frame)}:
     * an <em>execute</em> method on the delegate is ready to be called;</li>
     * <li>{@linkplain ProbeNode#onReturnValue(com.oracle.truffle.api.frame.VirtualFrame, Object)
     * onReturnValue(Frame,Object)}: an <em>execute</em> method on the delegate has just returned a
     * (possibly <code>null</code>) value;</li>
     * <li>
     * {@linkplain ProbeNode#onReturnExceptional(com.oracle.truffle.api.frame.VirtualFrame, Throwable)
     * onReturnExceptional(Frame,Throwable)}: an <em>execute</em> method on the delegate has just
     * thrown an exception.</li>
     * </ul>
     * </p>
     *
     * @param node the {@link Instrumentable} <em>delegate</em> to be adopted by the wrapper
     * @param probe the {@link ProbeNode probe node} to be adopted and sent execution events by the
     *            wrapper
     * @return a {@link WrapperNode wrapper} implementation
     * @since 0.12
     */
    WrapperNode createWrapper(T node, ProbeNode probe);

    /**
     * Nodes that the instrumentation framework inserts into guest language ASTs (between
     * {@link Instrumentable} guest language nodes and their parents) for the purpose of interposing
     * on execution events and reporting them via the instrumentation framework.
     *
     * @see #createWrapper(Node, ProbeNode)
     * @since 0.12
     */
    public interface WrapperNode {

        /**
         * The {@link Instrumentable} guest language node, adopted as a child, whose execution
         * events the wrapper reports to the instrumentation framework.
         *
         * @since 0.12
         */
        Node getDelegateNode();

        /**
         * A child of the wrapper, through which the wrapper reports execution events related to the
         * guest language <em>delegate</em> node.
         *
         * @since 0.12
         */
        ProbeNode getProbeNode();

    }

}