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 * The Universal Permissive License (UPL), Version 1.0
 *
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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
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package com.oracle.truffle.js.nodes.module;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Executed;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.FrameDescriptor;
import com.oracle.truffle.api.frame.FrameSlot;
import com.oracle.truffle.api.frame.MaterializedFrame;
import com.oracle.truffle.api.instrumentation.Tag;
import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.js.nodes.JavaScriptNode;
import com.oracle.truffle.js.nodes.access.JSReadFrameSlotNode;
import com.oracle.truffle.js.runtime.Errors;
import com.oracle.truffle.js.runtime.JSFrameUtil;
import com.oracle.truffle.js.runtime.objects.Dead;
import com.oracle.truffle.js.runtime.objects.ExportResolution;
import com.oracle.truffle.js.runtime.objects.JSModuleRecord;
import com.oracle.truffle.js.runtime.objects.JSModuleRecord.Status;

import java.util.Set;

Reads the value of a resolved import binding from a resolved binding record (module, binding
name) returned by ResolveExport. Specializes on the imported module's FrameDescriptor.
/**
 * Reads the value of a resolved import binding from a resolved binding record (module, binding
 * name) returned by ResolveExport. Specializes on the imported module's FrameDescriptor.
 */
public abstract class ReadImportBindingNode extends JavaScriptNode {

    @Child @Executed JavaScriptNode resolutionNode;

    ReadImportBindingNode(JavaScriptNode resolutionNode) {
        this.resolutionNode = resolutionNode;
    }

    public static JavaScriptNode create(JavaScriptNode resolutionNode) {
        return ReadImportBindingNodeGen.create(resolutionNode);
    }

    @Specialization(guards = {"frameDescriptor == resolution.getModule().getFrameDescriptor()", "bindingName.equals(resolution.getBindingName())"}, limit = "1")
    static Object doCached(ExportResolution resolution,
                    @Cached("resolution.getModule().getFrameDescriptor()") @SuppressWarnings("unused") FrameDescriptor frameDescriptor,
                    @Cached("resolution.getBindingName()") @SuppressWarnings("unused") String bindingName,
                    @Cached("create(frameDescriptor.findFrameSlot(bindingName))") JSReadFrameSlotNode readFrameSlot) {
        JSModuleRecord module = resolution.getModule();
        assert module.getStatus().compareTo(Status.Linked) >= 0 : module.getStatus();
        MaterializedFrame environment = JSFrameUtil.castMaterializedFrame(module.getEnvironment());
        Object value = readFrameSlot.execute(environment);
        assert value != Dead.instance();
        return value;
    }

    @TruffleBoundary
    @Specialization(replaces = {"doCached"})
    final Object doUncached(ExportResolution resolution) {
        JSModuleRecord module = resolution.getModule();
        assert module.getStatus().compareTo(Status.Linked) >= 0 : module.getStatus();
        String bindingName = resolution.getBindingName();
        FrameSlot frameSlot = module.getFrameDescriptor().findFrameSlot(bindingName);
        boolean hasTemporalDeadZone = JSFrameUtil.hasTemporalDeadZone(frameSlot);
        MaterializedFrame environment = JSFrameUtil.castMaterializedFrame(module.getEnvironment());
        Object value = environment.getValue(frameSlot);
        if (hasTemporalDeadZone) {
            if (value == Dead.instance()) {
                // Uninitialized binding
                throw Errors.createReferenceErrorNotDefined(bindingName, this);
            }
        } else {
            assert value != Dead.instance();
        }
        return value;
    }

    @Specialization(guards = "isJSModuleNamespace(namespace)")
    static Object doNamespace(DynamicObject namespace) {
        return namespace;
    }

    @Override
    protected JavaScriptNode copyUninitialized(Set<Class<? extends Tag>> materializedTags) {
        return create(cloneUninitialized(resolutionNode, materializedTags));
    }

}