com.google.gitiles.DescribeServlet.java Source code

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Here is the source code for com.google.gitiles.DescribeServlet.java

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// Copyright 2013 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (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 com.google.gitiles;

import static javax.servlet.http.HttpServletResponse.SC_BAD_REQUEST;
import static javax.servlet.http.HttpServletResponse.SC_NOT_FOUND;

import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableMap;
import com.google.gson.reflect.TypeToken;

import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.NameRevCommand;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.errors.AmbiguousObjectException;
import org.eclipse.jgit.errors.RevisionSyntaxException;
import org.eclipse.jgit.http.server.ServletUtils;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.Repository;

import java.io.IOException;
import java.io.Writer;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/** Serves an API result describing an object. */
public class DescribeServlet extends BaseServlet {
    private static final long serialVersionUID = 1L;

    private static final String ALL_PARAM = "all";
    private static final String CONTAINS_PARAM = "contains";
    private static final String TAGS_PARAM = "tags";

    private static boolean getBooleanParam(GitilesView view, String name) {
        List<String> values = view.getParameters().get(name);
        return !values.isEmpty() && (values.get(0).isEmpty() || values.get(0).equals("1"));
    }

    protected DescribeServlet(GitilesAccess.Factory accessFactory) {
        super(null, accessFactory);
    }

    @Override
    protected void doGetText(HttpServletRequest req, HttpServletResponse res) throws IOException {
        String name = describe(ServletUtils.getRepository(req), ViewFilter.getView(req), req, res);
        if (name == null) {
            return;
        }
        Writer out = startRenderText(req, res);
        out.write(RefServlet.sanitizeRefForText(name));
        out.close();
    }

    @Override
    protected void doGetJson(HttpServletRequest req, HttpServletResponse res) throws IOException {
        String name = describe(ServletUtils.getRepository(req), ViewFilter.getView(req), req, res);
        if (name == null) {
            return;
        }
        renderJson(req, res, ImmutableMap.of(ViewFilter.getView(req).getPathPart(), name),
                new TypeToken<Map<String, String>>() {
                }.getType());
    }

    private ObjectId resolve(Repository repo, GitilesView view, HttpServletRequest req, HttpServletResponse res)
            throws IOException {
        String rev = view.getPathPart();
        try {
            return repo.resolve(rev);
        } catch (RevisionSyntaxException e) {
            renderTextError(req, res, SC_BAD_REQUEST,
                    "Invalid revision syntax: " + RefServlet.sanitizeRefForText(rev));
            return null;
        } catch (AmbiguousObjectException e) {
            renderTextError(req, res, SC_BAD_REQUEST, String.format("Ambiguous short SHA-1 %s (%s)",
                    e.getAbbreviatedObjectId(), Joiner.on(", ").join(e.getCandidates())));
            return null;
        }
    }

    private String describe(Repository repo, GitilesView view, HttpServletRequest req, HttpServletResponse res)
            throws IOException {
        if (!getBooleanParam(view, CONTAINS_PARAM)) {
            res.setStatus(SC_BAD_REQUEST);
            return null;
        }
        ObjectId id = resolve(repo, view, req, res);
        if (id == null) {
            return null;
        }
        NameRevCommand cmd = nameRevCommand(id, req, res);
        if (cmd == null) {
            return null;
        }
        String name;
        try {
            name = cmd.call().get(id);
        } catch (GitAPIException e) {
            throw new IOException(e);
        }
        if (name == null) {
            res.setStatus(SC_NOT_FOUND);
            return null;
        }
        return name;
    }

    private NameRevCommand nameRevCommand(ObjectId id, HttpServletRequest req, HttpServletResponse res)
            throws IOException {
        Repository repo = ServletUtils.getRepository(req);
        GitilesView view = ViewFilter.getView(req);
        NameRevCommand cmd = new Git(repo).nameRev();
        boolean all = getBooleanParam(view, ALL_PARAM);
        boolean tags = getBooleanParam(view, TAGS_PARAM);
        if (all && tags) {
            renderTextError(req, res, SC_BAD_REQUEST, "Cannot specify both \"all\" and \"tags\"");
            return null;
        }
        if (all) {
            cmd.addPrefix(Constants.R_REFS);
        } else if (tags) {
            cmd.addPrefix(Constants.R_TAGS);
        } else {
            cmd.addAnnotatedTags();
        }
        cmd.add(id);
        return cmd;
    }
}