net.sf.saxon.expr.instruct.ApplyImports Maven / Gradle / Ivy

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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2018-2023 Saxonica Limited
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

package net.sf.saxon.expr.instruct;

import net.sf.saxon.Controller;
import net.sf.saxon.expr.Component;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.XPathContextMajor;
import net.sf.saxon.expr.elab.Elaborator;
import net.sf.saxon.expr.elab.PushElaborator;
import net.sf.saxon.expr.elab.PushEvaluator;
import net.sf.saxon.expr.parser.ExpressionTool;
import net.sf.saxon.expr.parser.RebindingMap;
import net.sf.saxon.om.Item;
import net.sf.saxon.om.StandardNames;
import net.sf.saxon.s9api.Location;
import net.sf.saxon.trace.ExpressionPresenter;
import net.sf.saxon.trace.TemplateRuleTraceListener;
import net.sf.saxon.trans.Mode;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.trans.XsltController;
import net.sf.saxon.trans.rules.Rule;


/**
 * An xsl:apply-imports element in the stylesheet.
 */

public class ApplyImports extends ApplyNextMatchingTemplate implements ITemplateCall {

    public ApplyImports() {
    }

    /**
     * Get the name of this instruction for diagnostic and tracing purposes
     */
    @Override
    public int getInstructionNameCode() {
        return StandardNames.XSL_APPLY_IMPORTS;
    }

    /**
     * Copy an expression. This makes a deep copy.
     *
     * @return the copy of the original expression
     * @param rebindings the rebinding map
     */

    /*@NotNull*/
    @Override
    public Expression copy(RebindingMap rebindings) {
        ApplyImports ai2 = new ApplyImports();
        ai2.setActualParams(WithParam.copy(ai2, getActualParams(), rebindings));
        ai2.setTunnelParams(WithParam.copy(ai2, getTunnelParams(), rebindings));
        ExpressionTool.copyLocationInfo(this, ai2);
        return ai2;
    }


    /**
     * Diagnostic print of expression structure. The abstract expression tree
     * is written to the supplied output destination.
     */

    @Override
    public void export(ExpressionPresenter out) throws XPathException {
        out.startElement("applyImports", this);
        out.emitAttribute("flags", "i");  // used to mean "allow any item" i.e. non-nodes
        if (getActualParams().length != 0) {
            WithParam.exportParameters(getActualParams(), out, false);
        }
        if (getTunnelParams().length != 0) {
            WithParam.exportParameters(getTunnelParams(), out, true);
        }
        out.endElement();
    }


    /**
     * Get the (partial) name of a class that supports streaming of this kind of expression
     *
     * @return the partial name of a class that can be instantiated to provide streaming support in Saxon-EE,
     * or null if there is no such class
     */
    @Override
    public String getStreamerName() {
        return "ApplyImports";
    }

    public Elaborator getElaborator() {
        return new ApplyImportsElaborator();
    }

    private static class ApplyImportsElaborator extends PushElaborator {

        @Override
        public PushEvaluator elaborateForPush() {
            ApplyImports expr = (ApplyImports) getExpression();
            Location loc = expr.getLocation();
            return (output, context) -> {
                Controller controller = context.getController();
                assert controller != null;

                // handle parameters if any
                ParameterSet params = assembleParams(context, expr.getActualParams());
                ParameterSet tunnels = assembleTunnelParams(context, expr.getTunnelParams());

                Rule currentTemplateRule = context.getCurrentTemplateRule();
                if (currentTemplateRule == null) {
                    throw new XPathException("There is no current template rule")
                            .withXPathContext(context)
                            .withErrorCode("XTDE0560")
                            .withLocation(loc);
                }

                int min = currentTemplateRule.getMinImportPrecedence();
                int max = currentTemplateRule.getPrecedence() - 1;
                Component.M modeComponent = context.getCurrentMode();
                if (modeComponent == null) {
                    throw new AssertionError("Current mode is null");
                }
                Item currentItem = context.getCurrentIterator().current();

                Mode mode = modeComponent.getActor();
                Rule rule = mode.getRule(currentItem, min, max, context);
                if (rule == null) {             // use the default action for the node
                    mode.getBuiltInRuleSet().process(currentItem, params, tunnels, output, context, loc);
                } else {
                    XPathContextMajor c2 = context.newContext();
                    TemplateRule nh = (TemplateRule) rule.getAction();
                    nh.initialize();
                    c2.setOrigin(expr);
                    c2.setLocalParameters(params);
                    c2.setTunnelParameters(tunnels);
                    c2.openStackFrame(nh.getStackFrameMap());
                    c2.setCurrentTemplateRule(rule);
                    c2.setCurrentComponent(modeComponent);
                    c2.setCurrentMergeGroupIterator(null);
                    if (mode.isModeTracing()) {
                        TemplateRuleTraceListener tracer = ((XsltController) controller).getTemplateRuleTraceListener();
                        tracer.enter("apply-imports", loc, currentItem, nh);
                        nh.apply(output, c2);
                        tracer.leave();
                    } else {
                        nh.apply(output, c2);
                    }
                }
                return null; // we could use tail recursion, but we don't
            };
        }
    }


}