src/main/java/org/apache/jenkins/gitpubsub/ASFGitSCMFile.java

/*
 * Licensed under the Apache License,Version2.0(the"License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,software
 * distributed under the License is distributed on an"AS IS"BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jenkins.gitpubsub;

import edu.umd.cs.findbugs.annotations.NonNull;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import jenkins.scm.api.SCMFile;
import org.eclipse.jgit.lib.Constants;
import org.jsoup.HttpStatusException;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

import static org.apache.jenkins.gitpubsub.ASFGitSCMFileSystem.fetchDocument;
import static org.apache.jenkins.gitpubsub.ASFGitSCMNavigator.RFC_2822;

/**
 * A {@link SCMFile} that is backed by a GitWeb server hosted on {@code apache.org}.
 */
public class ASFGitSCMFile extends SCMFile {

    /**
     * The Git URL from which the project and gitweb server can be derived.
     */
    private final String remote;
    /**
     * The ref or hash that the file is being accessed for.
     */
    private final String refOrHash;

    /**
     * Root constructor.
     * @param remote The Git URL from which the project and gitweb server can be derived.
     * @param refOrHash The ref or hash that the file is being accessed for.
     */
    ASFGitSCMFile(String remote, String refOrHash) {
        this.remote = remote;
        this.refOrHash = refOrHash;
    }

    /**
     * Child constructor.
     * @param parent the parent file.
     * @param name the name of the child.
     */
    ASFGitSCMFile(@NonNull ASFGitSCMFile parent, String name) {
        super(parent, name);
        this.remote = parent.remote;
        this.refOrHash = parent.refOrHash;
    }

    /**
     * {@inheritDoc}
     */
    @NonNull
    @Override
    protected SCMFile newChild(@NonNull String name, boolean assumeIsDirectory) {
        return new ASFGitSCMFile(this, name);
    }

    /**
     * {@inheritDoc}
     */
    @NonNull
    @Override
    public Iterable<SCMFile> children() throws IOException, InterruptedException {
        String treeUrl = ASFGitSCMFileSystem.buildTemplateWithRemote("{+server}{?p}{;a,hb,f}", remote)
                .set("a", "tree")
                .set("hb", refOrHash)
                .set("f", isRoot() ? null : getPath())
                .expand();
        Document doc = fetchDocument(treeUrl);
        Elements elements = doc.select("table.tree tr td.list a");
        List<SCMFile> result = new ArrayList<>();
        for (Element element : elements) {
            String name = element.text();
            if (".".equals(name) || "..".equals(name)) {
                continue;
            }
            Element mode = element.parent().previousElementSibling().previousElementSibling();
            if (mode.text().startsWith("d")) {
                result.add(newChild(element.text(), true));
            } else {
                result.add(newChild(element.text(), false));
            }
        }
        return result;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public long lastModified() throws IOException, InterruptedException {
        if (isRoot()) {
            if (refOrHash.startsWith(Constants.R_TAGS)) {
                String tagUrl = ASFGitSCMFileSystem.buildTemplateWithRemote("{+server}{?p}{;a,h}", remote)
                        .set("a", "tag")
                        .set("h", refOrHash)
                        .expand();
                Document doc;
                try {
                    doc = fetchDocument(tagUrl);
                } catch (HttpStatusException e) {
                    if (e.getStatusCode() == 404) {
                        // must be a lightweight tag
                        doc = null;
                    } else {
                        return 0L;
                    }
                }
                if (doc != null) {
                    Elements elements = doc.select("table.object_header tr td span.datetime");
                    try {
                        return new SimpleDateFormat(RFC_2822).parse(elements.get(0).text())
                                .getTime();
                    } catch (ParseException | IndexOutOfBoundsException e) {
                        return 0L;
                    }
                }
            }
            String commitUrl = ASFGitSCMFileSystem.buildTemplateWithRemote("{+server}{?p}{;a,h}", remote)
                    .set("a", "commit")
                    .set("h", refOrHash)
                    .expand();
            Document doc = fetchDocument(commitUrl);
            Elements elements = doc.select("table.object_header tr td span.datetime");
            try {
                return new SimpleDateFormat(RFC_2822).parse(elements.get(1).text()).getTime();
            } catch (ParseException | IndexOutOfBoundsException e) {
                return 0L;
            }
        }
        String historyUrl = ASFGitSCMFileSystem.buildTemplateWithRemote("{+server}{?p}{;a,hb,f}", remote)
                .set("a", "history")
                .set("hb", refOrHash)
                .set("f", getPath())
                .expand();
        Document doc = fetchDocument(historyUrl);
        Elements elements = doc.select("table.history tr td a.subject");
        if (elements.isEmpty()) {
            return 0L;
        }
        Matcher href = ASFGitSCMFileSystem.URL_EXTRACT_H.matcher(elements.get(0).attr("href"));
        if (!href.matches()) {
            return 0L;
        }
        String commitUrl = ASFGitSCMFileSystem.buildTemplateWithRemote("{+server}{?p}{;a,h}", remote)
                .set("a", "commit")
                .set("h", href.group(1))
                .expand();
        doc = fetchDocument(commitUrl);
        elements = doc.select("table.object_header tr td span.datetime");
        try {
            return new SimpleDateFormat(RFC_2822).parse(elements.get(1).text()).getTime();
        } catch (ParseException | IndexOutOfBoundsException e) {
            return 0L;
        }
    }

    /**
     * {@inheritDoc}
     */
    @NonNull
    @Override
    protected Type type() throws IOException, InterruptedException {
        String path = getPath();
        int lastSlash = path.lastIndexOf('/');
        String treeUrl = ASFGitSCMFileSystem.buildTemplateWithRemote("{+server}{?p}{;a,hb,f}", remote)
                .set("a", "tree")
                .set("hb", refOrHash)
                .set("f", lastSlash == -1 ? null : path.substring(0, lastSlash))
                .expand();
        Document doc = fetchDocument(treeUrl);
        Elements elements = doc.select("table.tree tr td.list a");
        for (Element element : elements) {
            if (element.text().equals(getName())) {
                Element mode = element.parent().previousElementSibling().previousElementSibling();
                if (mode.text().startsWith("d")) {
                    return Type.DIRECTORY;
                } else if (mode.text().startsWith("-")) {
                    return Type.REGULAR_FILE;
                }
            }
        }
        return Type.NONEXISTENT;
    }

    /**
     * {@inheritDoc}
     */
    @NonNull
    @Override
    public InputStream content() throws IOException, InterruptedException {
        String blobUrl = ASFGitSCMFileSystem.buildTemplateWithRemote("{+server}{?p}{;a,f,hb}", remote)
                .set("a", "blob_plain")
                .set("hb", refOrHash)
                .set("f", getPath())
                .expand();
        return new URL(blobUrl).openStream();
    }
}