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An XProc 1.0 processor
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package com.xmlcalabash.runtime;

import java.math.BigDecimal;
import java.math.MathContext;

import com.xmlcalabash.core.XProcRuntime;
import com.xmlcalabash.core.XProcException;
import com.xmlcalabash.core.XProcData;
import com.xmlcalabash.io.ReadablePipe;
import com.xmlcalabash.io.ReadOnlyPipe;
import com.xmlcalabash.io.Pipe;
import com.xmlcalabash.io.WritablePipe;
import com.xmlcalabash.model.Step;
import com.xmlcalabash.model.RuntimeValue;
import com.xmlcalabash.model.Variable;
import com.xmlcalabash.model.Option;
import com.xmlcalabash.util.MessageFormatter;
import com.xmlcalabash.util.XProcMessageListenerHelper;
import net.sf.saxon.s9api.SaxonApiException;
import net.sf.saxon.s9api.XdmNode;
import net.sf.saxon.s9api.QName;

import java.util.Vector;

/**
 * Created by IntelliJ IDEA.
 * User: ndw
 * Date: Oct 14, 2008
 * Time: 5:44:42 AM
 * To change this template use File | Settings | File Templates.
 */
public class XForEach extends XCompoundStep {
    private Pipe current = null;
    private int sequencePosition = 0;
    private int sequenceLength = 0;

    public XForEach(XProcRuntime runtime, Step step, XCompoundStep parent) {
        super(runtime, step, parent);
    }

    public ReadablePipe getBinding(String stepName, String portName) {
        if (name.equals(stepName) && ("#current".equals(portName) || "current".equals(portName))) {
            if (current == null) {
                current = new Pipe(runtime);
            }
            return new ReadOnlyPipe(runtime, current.documents());
        } else {
            return super.getBinding(stepName, portName);
        }
    }

    protected void copyInputs() throws SaxonApiException {
        // nop;
    }

    public void reset() {
        super.reset();
        sequenceLength = 0;
        sequencePosition = 0;
    }
    
    protected void doRun() throws SaxonApiException {
        logger.trace("Running p:for-each " + step.getName());

        XProcData data = runtime.getXProcData();
        data.openFrame(this);

        if (current == null) {
            current = new Pipe(runtime);
        }

        String iport = "#iteration-source";

        sequencePosition = 0;
        sequenceLength = 0;

        inScopeOptions = parent.getInScopeOptions();

        // FIXME: Do I really have to do this? At the very least, only do it if we have to!
        Vector nodes = new Vector ();
        for (ReadablePipe is_reader : inputs.get(iport)) {
            while (is_reader.moreDocuments()) {
                XdmNode is_doc = is_reader.read();
                logger.trace(MessageFormatter.nodeMessage(step.getNode(), "Input copy from " + is_reader));
                logger.trace(MessageFormatter.nodeMessage(step.getNode(), is_doc.toString()));
                nodes.add(is_doc);
                sequenceLength++;
            }
        }

        runtime.getXProcData().setIterationSize(sequenceLength);

        runtime.start(this);

        try {
            XProcMessageListenerHelper.openStep(runtime, this);
            try {
            BigDecimal numberOfNodes = new BigDecimal(nodes.size());
            for (XdmNode is_doc : nodes) {
                runtime.getMessageListener().openStep(this, getNode(), null, null, BigDecimal.ONE.divide(numberOfNodes, MathContext.DECIMAL128));
                try {

                // Setup the current port before we compute variables!
                current.resetWriter();
                current.write(is_doc);
                logger.trace(MessageFormatter.nodeMessage(step.getNode(), "Copy to current"));

                sequencePosition++;
                runtime.getXProcData().setIterationPosition(sequencePosition);

                for (Variable var : step.getVariables()) {
                    RuntimeValue value = computeValue(var);
                    inScopeOptions.put(var.getName(), value);
                }

                // N.B. At this time, there are no compound steps that accept parameters or options,
                // so the order in which we calculate them doesn't matter. That will change if/when
                // there are such compound steps.

                // Calculate all the variables
                inScopeOptions = parent.getInScopeOptions();
                for (Variable var : step.getVariables()) {
                    RuntimeValue value = computeValue(var);
                    inScopeOptions.put(var.getName(), value);
                }

                for (XStep step : subpipeline) {
                    step.run();
                }

                for (String port : inputs.keySet()) {
                    if (port.startsWith("|")) {
                        String wport = port.substring(1);

                        boolean seqOk = step.getOutput(wport).getSequence();
                        int docsCopied = 0;

                        WritablePipe pipe = outputs.get(wport);
                        // The output of a for-each is a sequence, irrespective of what the output says
                        pipe.canWriteSequence(true);

                        for (ReadablePipe reader : inputs.get(port)) {
                            reader.canReadSequence(true); // Hack again!
                            while (reader.moreDocuments()) {
                                XdmNode doc = reader.read();
                                pipe.write(doc);
                                docsCopied++;
                                logger.trace(MessageFormatter.nodeMessage(step.getNode(), "Output copy from " + reader + " to " + pipe));
                            }
                            reader.resetReader();
                        }

                        if (docsCopied != 1 && !seqOk) {
                            throw XProcException.dynamicError(6, "Writing to " + wport + " on " + getStep().getName());
                        }
                    }
                }

                for (XStep step : subpipeline) {
                    step.reset();
                }

                } finally {
                    runtime.getMessageListener().closeStep();
                }
            }
            } finally {
                runtime.getMessageListener().closeStep();
            }
        } finally {
            for (String port : inputs.keySet()) {
                if (port.startsWith("|")) {
                    String wport = port.substring(1);
                    WritablePipe pipe = outputs.get(wport);
                    pipe.close(); // Indicate that we're done
                }
            }
            runtime.finish(this);
            data.closeFrame();
        }
    }
}