com.google.gerrit.server.patch.PatchFile.java Source code

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Here is the source code for com.google.gerrit.server.patch.PatchFile.java

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// 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.

package com.google.gerrit.server.patch;

import com.google.gerrit.common.errors.CorruptEntityException;
import com.google.gerrit.common.errors.NoSuchEntityException;
import com.google.gerrit.reviewdb.client.Patch;

import org.eclipse.jgit.errors.CorruptObjectException;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.TreeWalk;

import java.io.IOException;

/** State supporting processing of a single {@link Patch} instance. */
public class PatchFile {
    private final Repository repo;
    private final PatchListEntry entry;
    private final RevTree aTree;
    private final RevTree bTree;

    private Text a;
    private Text b;

    public PatchFile(final Repository repo, final PatchList patchList, final String fileName)
            throws MissingObjectException, IncorrectObjectTypeException, IOException {
        this.repo = repo;
        this.entry = patchList.get(fileName);

        try (ObjectReader reader = repo.newObjectReader(); RevWalk rw = new RevWalk(reader)) {
            final RevCommit bCommit = rw.parseCommit(patchList.getNewId());

            if (Patch.COMMIT_MSG.equals(fileName)) {
                if (patchList.isAgainstParent()) {
                    a = Text.EMPTY;
                } else {
                    a = Text.forCommit(reader, patchList.getOldId());
                }
                b = Text.forCommit(reader, bCommit);

                aTree = null;
                bTree = null;

            } else {
                if (patchList.getOldId() != null) {
                    aTree = rw.parseTree(patchList.getOldId());
                } else {
                    final RevCommit p = bCommit.getParent(0);
                    rw.parseHeaders(p);
                    aTree = p.getTree();
                }
                bTree = bCommit.getTree();
            }
        }
    }

    /**
     * Extract a line from the file, as a string.
     *
     * @param file the file index to extract.
     * @param line the line number to extract (1 based; 1 is the first line).
     * @return the string version of the file line.
     * @throws CorruptEntityException the patch cannot be read.
     * @throws IOException the patch or complete file content cannot be read.
     * @throws NoSuchEntityException
     */
    public String getLine(final int file, final int line)
            throws CorruptEntityException, IOException, NoSuchEntityException {
        switch (file) {
        case 0:
            if (a == null) {
                a = load(aTree, entry.getOldName());
            }
            return a.getString(line - 1);

        case 1:
            if (b == null) {
                b = load(bTree, entry.getNewName());
            }
            return b.getString(line - 1);

        default:
            throw new NoSuchEntityException();
        }
    }

    /**
     * Return number of lines in file.
     *
     * @param file the file index to extract.
     * @return number of lines in file.
     * @throws CorruptEntityException the patch cannot be read.
     * @throws IOException the patch or complete file content cannot be read.
     * @throws NoSuchEntityException the file is not exist.
     */
    public int getLineCount(final int file) throws CorruptEntityException, IOException, NoSuchEntityException {
        switch (file) {
        case 0:
            if (a == null) {
                a = load(aTree, entry.getOldName());
            }
            return a.size();

        case 1:
            if (b == null) {
                b = load(bTree, entry.getNewName());
            }
            return b.size();

        default:
            throw new NoSuchEntityException();
        }
    }

    private Text load(final ObjectId tree, final String path)
            throws MissingObjectException, IncorrectObjectTypeException, CorruptObjectException, IOException {
        if (path == null) {
            return Text.EMPTY;
        }
        final TreeWalk tw = TreeWalk.forPath(repo, path, tree);
        if (tw == null) {
            return Text.EMPTY;
        }
        if (tw.getFileMode(0).getObjectType() != Constants.OBJ_BLOB) {
            return Text.EMPTY;
        }
        return new Text(repo.open(tw.getObjectId(0), Constants.OBJ_BLOB));
    }
}