Java tutorial
/* * Copyright (c) 2011 Kevin Sawicki <kevinsawicki@gmail.com> * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to * deal in the Software without restriction, including without limitation the * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ package org.gitective.core; import static java.lang.Integer.MAX_VALUE; import static org.eclipse.jgit.diff.RawText.EMPTY_TEXT; import static org.eclipse.jgit.diff.RawTextComparator.DEFAULT; import static org.eclipse.jgit.lib.Constants.CHARACTER_ENCODING; import static org.eclipse.jgit.lib.Constants.HEAD; import static org.eclipse.jgit.lib.Constants.OBJ_BLOB; import static org.eclipse.jgit.lib.FileMode.TYPE_FILE; import static org.eclipse.jgit.lib.FileMode.TYPE_MASK; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.util.Collection; import java.util.Collections; import org.eclipse.jgit.diff.Edit; import org.eclipse.jgit.diff.HistogramDiff; import org.eclipse.jgit.diff.RawText; import org.eclipse.jgit.diff.RawTextComparator; import org.eclipse.jgit.lib.ObjectId; import org.eclipse.jgit.lib.ObjectReader; import org.eclipse.jgit.lib.ObjectStream; import org.eclipse.jgit.lib.Repository; import org.eclipse.jgit.revwalk.RevCommit; import org.eclipse.jgit.treewalk.TreeWalk; /** * Utilities for dealing with Git blobs. * <p> * This class provides helpers for getting the content and the ids of blobs at * different paths and commits. * <p> * This class also provides helpers for computing the differences between the * content of blobs. */ public abstract class BlobUtils { /** * Get the contents of the the blob with the given id as a byte array. * * @param repository * @param id * @return blob bytes */ protected static byte[] getBytes(final Repository repository, final ObjectId id) { try { return repository.open(id, OBJ_BLOB).getCachedBytes(MAX_VALUE); } catch (IOException e) { throw new GitException(e, repository); } } /** * Get the contents of the the blob with the given id as a byte array. * * @param reader * @param id * @return blob bytes */ protected static byte[] getBytes(final ObjectReader reader, final ObjectId id) { try { return reader.open(id, OBJ_BLOB).getCachedBytes(MAX_VALUE); } catch (IOException e) { throw new GitException(e, null); } } /** * Convert byte array to UTF-8 {@link String} * * @param repository * @param raw * @return UTF-8 string or null if bytes are null */ protected static String toString(final Repository repository, final byte[] raw) { if (raw == null) return null; try { return new String(raw, CHARACTER_ENCODING); } catch (UnsupportedEncodingException e) { throw new GitException(e, repository); } } /** * Get the contents of the the blob with the given id as a UTF-8 * {@link String}. * * @param repository * @param id * @return content of blob as UTF-8 string */ public static String getContent(final Repository repository, final ObjectId id) { if (repository == null) throw new IllegalArgumentException(Assert.formatNotNull("Repository")); if (id == null) throw new IllegalArgumentException(Assert.formatNotNull("Object id")); return toString(repository, getBytes(repository, id)); } /** * Get the id of the blob at the path in the given commit. * * @param repository * @param commit * @param path * @return blob id, null if not present */ protected static ObjectId lookupId(final Repository repository, final RevCommit commit, final String path) { final TreeWalk walk; try { walk = TreeWalk.forPath(repository, path, commit.getTree()); } catch (IOException e) { throw new GitException(e, repository); } if (walk == null) return null; if ((walk.getRawMode(0) & TYPE_MASK) != TYPE_FILE) return null; return walk.getObjectId(0); } /** * Get the contents of the the blob in the commit located at the given path * as a byte array. * * @param repository * @param commit * @param path * @return raw content */ protected static byte[] getBytes(final Repository repository, final RevCommit commit, final String path) { final ObjectId id = lookupId(repository, commit, path); return id != null ? getBytes(repository, id) : null; } /** * Get raw contents of the blob at the given path in the commit that the * revision references. * * @param repository * @param revision * @param path * @return raw content or null if no blob with path at given revision */ public static byte[] getRawContent(final Repository repository, final String revision, final String path) { if (repository == null) throw new IllegalArgumentException(Assert.formatNotNull("Repository")); if (revision == null) throw new IllegalArgumentException(Assert.formatNotNull("Revision")); if (revision.length() == 0) throw new IllegalArgumentException(Assert.formatNotEmpty("Revision")); if (path == null) throw new IllegalArgumentException(Assert.formatNotNull("Path")); if (path.length() == 0) throw new IllegalArgumentException(Assert.formatNotEmpty("Path")); final RevCommit commit = CommitUtils.parse(repository, CommitUtils.strictResolve(repository, revision)); return getBytes(repository, commit, path); } /** * Get the raw contents of the blob in the commit located at the given path. * * @param repository * @param commitId * @param path * @return raw content or null if no blob with path at given commit */ public static byte[] getRawContent(final Repository repository, final ObjectId commitId, final String path) { if (repository == null) throw new IllegalArgumentException(Assert.formatNotNull("Repository")); if (commitId == null) throw new IllegalArgumentException(Assert.formatNotNull("Commit id")); if (path == null) throw new IllegalArgumentException(Assert.formatNotNull("Path")); if (path.length() == 0) throw new IllegalArgumentException(Assert.formatNotEmpty("Path")); final RevCommit commit = CommitUtils.parse(repository, commitId); return getBytes(repository, commit, path); } /** * Get the contents of the blob in the commit located at the given path. * * @param repository * @param commitId * @param path * @return contents or null if no blob with path at given commit */ public static String getContent(final Repository repository, final ObjectId commitId, final String path) { return toString(repository, getRawContent(repository, commitId, path)); } /** * Get the contents of the blob at the given path in the commit that the * revision references. * * @param repository * @param revision * @param path * @return contents or null if no blob with path at given revision */ public static String getContent(final Repository repository, final String revision, final String path) { return toString(repository, getRawContent(repository, revision, path)); } /** * Get the contents of the blob at the given path in the commit that HEAD * references. * * @param repository * @param path * @return content or null if no blob with path at HEAD commit */ public static String getHeadContent(final Repository repository, final String path) { return getContent(repository, HEAD, path); } /** * Get the raw contents of the blob at the given path in the commit that * HEAD references. * * @param repository * @param path * @return content or null if no blob with path at HEAD commit */ public static byte[] getRawHeadContent(final Repository repository, final String path) { return getRawContent(repository, HEAD, path); } /** * Get the id of the blob at the path in the commit that the given revision * references. * * @param repository * @param revision * @param path * @return blob id */ public static ObjectId getId(final Repository repository, final String revision, final String path) { if (repository == null) throw new IllegalArgumentException(Assert.formatNotNull("Repository")); if (revision == null) throw new IllegalArgumentException(Assert.formatNotNull("Revision")); if (revision.length() == 0) throw new IllegalArgumentException(Assert.formatNotEmpty("Revision")); if (path == null) throw new IllegalArgumentException(Assert.formatNotNull("Path")); if (path.length() == 0) throw new IllegalArgumentException(Assert.formatNotEmpty("Path")); final RevCommit commit = CommitUtils.parse(repository, CommitUtils.strictResolve(repository, revision)); return lookupId(repository, commit, path); } /** * Get the id of the blob at the path in the commit that HEAD currently * references. * * @param repository * @param path * @return blob id */ public static ObjectId getHeadId(final Repository repository, final String path) { return getId(repository, HEAD, path); } /** * Get the id of the blob at the path in the commit that the given revision * references. * * @param repository * @param commitId * @param path * @return blob id */ public static ObjectId getId(final Repository repository, final ObjectId commitId, final String path) { if (repository == null) throw new IllegalArgumentException(Assert.formatNotNull("Repository")); if (commitId == null) throw new IllegalArgumentException(Assert.formatNotNull("Commit id")); if (path == null) throw new IllegalArgumentException(Assert.formatNotNull("Path")); if (path.length() == 0) throw new IllegalArgumentException(Assert.formatNotEmpty("Path")); final RevCommit commit = CommitUtils.parse(repository, commitId); return lookupId(repository, commit, path); } /** * Open a stream to the contents of the blob at the path in the given commit * * @param repository * @param commitId * @param path * @return stream, null if no blob at given path */ public static ObjectStream getStream(final Repository repository, final ObjectId commitId, final String path) { if (repository == null) throw new IllegalArgumentException(Assert.formatNotNull("Repository")); if (commitId == null) throw new IllegalArgumentException(Assert.formatNotNull("Commit id")); if (path == null) throw new IllegalArgumentException(Assert.formatNotNull("Path")); if (path.length() == 0) throw new IllegalArgumentException(Assert.formatNotEmpty("Path")); final RevCommit commit = CommitUtils.parse(repository, commitId); final ObjectId blobId = lookupId(repository, commit, path); if (blobId == null) return null; try { return repository.open(blobId, OBJ_BLOB).openStream(); } catch (IOException e) { throw new GitException(e, repository); } } /** * Open a stream to the contents of the blob at the path in the commit that * HEAD currently references. * * @param repository * @param path * @return stream */ public static ObjectStream getHeadStream(final Repository repository, final String path) { return getStream(repository, HEAD, path); } /** * Open a stream to the contents of the blob at the path in the commit that * the given revision references. * * @param repository * @param revision * @param path * @return stream */ public static ObjectStream getStream(final Repository repository, final String revision, final String path) { if (repository == null) throw new IllegalArgumentException(Assert.formatNotNull("Repository")); if (revision == null) throw new IllegalArgumentException(Assert.formatNotNull("Revision")); if (revision.length() == 0) throw new IllegalArgumentException(Assert.formatNotEmpty("Revision")); if (path == null) throw new IllegalArgumentException(Assert.formatNotNull("Path")); if (path.length() == 0) throw new IllegalArgumentException(Assert.formatNotEmpty("Path")); final RevCommit commit = CommitUtils.parse(repository, CommitUtils.strictResolve(repository, revision)); final ObjectId blobId = lookupId(repository, commit, path); if (blobId == null) return null; try { return repository.open(blobId, OBJ_BLOB).openStream(); } catch (IOException e) { throw new GitException(e, repository); } } /** * Diff the blobs at the given object ids using the * {@link RawTextComparator#DEFAULT} comparator. * * @see #diff(Repository, ObjectId, ObjectId, RawTextComparator) * @param repository * @param blob1 * @param blob2 * @return list of edits */ public static Collection<Edit> diff(final Repository repository, final ObjectId blob1, final ObjectId blob2) { return diff(repository, blob1, blob2, DEFAULT); } /** * Diff the blobs at the given object ids. * <p> * This method will return an empty list if the content of either blob is * binary. * * @param repository * @param blob1 * @param blob2 * @param comparator * @return list of edits, never null */ public static Collection<Edit> diff(final Repository repository, final ObjectId blob1, final ObjectId blob2, final RawTextComparator comparator) { if (repository == null) throw new IllegalArgumentException(Assert.formatNotNull("Repository")); if (blob1 == null) throw new IllegalArgumentException(Assert.formatNotNull("Blob id 1")); if (blob2 == null) throw new IllegalArgumentException(Assert.formatNotNull("Blob id 2")); if (comparator == null) throw new IllegalArgumentException(Assert.formatNotNull("Comparator")); if (blob1.equals(blob2)) return Collections.emptyList(); final byte[] data1; if (!blob1.equals(ObjectId.zeroId())) { data1 = getBytes(repository, blob1); if (RawText.isBinary(data1)) return Collections.emptyList(); } else data1 = new byte[0]; final byte[] data2; if (!blob2.equals(ObjectId.zeroId())) { data2 = getBytes(repository, blob2); if (RawText.isBinary(data2)) return Collections.emptyList(); } else data2 = new byte[0]; return new HistogramDiff().diff(comparator, // data1.length > 0 ? new RawText(data1) : EMPTY_TEXT, // data2.length > 0 ? new RawText(data2) : EMPTY_TEXT); } /** * Diff the blobs at the given object ids using the * {@link RawTextComparator#DEFAULT} comparator. * * @see #diff(ObjectReader, ObjectId, ObjectId, RawTextComparator) * @param reader * @param blob1 * @param blob2 * @return list of edits */ public static Collection<Edit> diff(final ObjectReader reader, final ObjectId blob1, final ObjectId blob2) { return diff(reader, blob1, blob2, DEFAULT); } /** * Diff the blobs at the given object ids. * <p> * This method will return an empty list if the content of either blob is * binary. * * @param reader * @param blob1 * @param blob2 * @param comparator * @return list of edits, never null */ public static Collection<Edit> diff(final ObjectReader reader, final ObjectId blob1, final ObjectId blob2, final RawTextComparator comparator) { if (reader == null) throw new IllegalArgumentException(Assert.formatNotNull("Reader")); if (blob1 == null) throw new IllegalArgumentException(Assert.formatNotNull("Blob id 1")); if (blob2 == null) throw new IllegalArgumentException(Assert.formatNotNull("Blob id 2")); if (comparator == null) throw new IllegalArgumentException(Assert.formatNotNull("Comparator")); if (blob1.equals(blob2)) return Collections.emptyList(); final byte[] data1; if (!blob1.equals(ObjectId.zeroId())) { data1 = getBytes(reader, blob1); if (RawText.isBinary(data1)) return Collections.emptyList(); } else data1 = new byte[0]; final byte[] data2; if (!blob2.equals(ObjectId.zeroId())) { data2 = getBytes(reader, blob2); if (RawText.isBinary(data2)) return Collections.emptyList(); } else data2 = new byte[0]; return new HistogramDiff().diff(comparator, // data1.length > 0 ? new RawText(data1) : EMPTY_TEXT, // data2.length > 0 ? new RawText(data2) : EMPTY_TEXT); } }