com.pramati.gerrit.plugin.helpers.GetFileFromRepo.java Source code

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Here is the source code for com.pramati.gerrit.plugin.helpers.GetFileFromRepo.java

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package com.pramati.gerrit.plugin.helpers;

//Copyright (C) 2009 The Android Open Source Project
//
//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.

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

import org.eclipse.jgit.errors.RepositoryNotFoundException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectLoader;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.TreeWalk;

import com.google.gerrit.reviewdb.client.Change;
import com.google.gerrit.reviewdb.client.Patch;
import com.google.gerrit.reviewdb.client.PatchSet;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gerrit.reviewdb.server.ReviewDb;
import com.google.gerrit.server.git.GitRepositoryManager;
import com.google.gerrit.server.project.ChangeControl;
import com.google.gerrit.server.project.NoSuchChangeException;
import com.google.gwtorm.server.OrmException;
import com.google.inject.Inject;
import com.google.inject.Provider;

/**
 * Helper class to get file from the gerrit repository
 * 
 * @author dilip
 * 
 */
public class GetFileFromRepo {
    private static Provider<ReviewDb> requestDb;
    private static GitRepositoryManager repoManager;
    private static ChangeControl.Factory changeControl;

    @Inject
    public GetFileFromRepo(final GitRepositoryManager grm, final Provider<ReviewDb> sf,
            final ChangeControl.Factory ccf) {
        requestDb = sf;
        repoManager = grm;
        changeControl = ccf;
    }

    /**
     * returns the File Stream from the gerrit repository. returns "null" if the
     * given file not found in the repository.<br>
     * patchStr should like in given format::"changeid/patchsetID/filename" <br>
     * eg: 1/2/readme.md
     * 
     * @param patchStr
     * @return
     * @throws IOException
     */
    public static BufferedInputStream doGetFile(String patchStr) throws IOException {
        final Patch.Key patchKey;
        final Change.Id changeId;
        final Project project;
        final PatchSet patchSet;
        final Repository repo;
        final ReviewDb db;
        final ChangeControl control;
        try {
            patchKey = Patch.Key.parse(patchStr);
        } catch (NumberFormatException e) {
            return null;
        }
        changeId = patchKey.getParentKey().getParentKey();

        try {
            db = requestDb.get();
            control = changeControl.validateFor(changeId);

            project = control.getProject();
            patchSet = db.patchSets().get(patchKey.getParentKey());
            if (patchSet == null) {
                return null;
                // rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
            }
        } catch (NoSuchChangeException e) {
            // rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return null;
        } catch (OrmException e) {
            // getServletContext().log("Cannot query database", e);
            // rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            return null;
        }

        try {
            repo = repoManager.openRepository(project.getNameKey());
        } catch (RepositoryNotFoundException e) {
            // getServletContext().log("Cannot open repository", e);
            // rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            return null;
        }

        final ObjectLoader blobLoader;
        final RevCommit fromCommit;
        final String path = patchKey.getFileName();
        try {
            final ObjectReader reader = repo.newObjectReader();
            try {
                final RevWalk rw = new RevWalk(reader);
                final RevCommit c;
                final TreeWalk tw;

                c = rw.parseCommit(ObjectId.fromString(patchSet.getRevision().get()));
                fromCommit = c;

                tw = TreeWalk.forPath(reader, path, fromCommit.getTree());
                if (tw == null) {
                    // rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
                    return null;
                }

                if (tw.getFileMode(0).getObjectType() == Constants.OBJ_BLOB) {
                    blobLoader = reader.open(tw.getObjectId(0), Constants.OBJ_BLOB);

                } else {
                    // rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
                    return null;
                }
            } finally {
                reader.release();
            }
        } catch (IOException e) {
            // getServletContext().log("Cannot read repository", e);
            // rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            return null;
        } catch (RuntimeException e) {
            // getServletContext().log("Cannot read repository", e);
            // rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            return null;
        } finally {
            repo.close();
        }
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        blobLoader.copyTo(out);
        byte[] b = out.toByteArray();
        BufferedInputStream br = new BufferedInputStream(new ByteArrayInputStream(b));
        return br;
    }
}