/*
* Copyright (C) 2008, Google Inc.
* Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
* Copyright (C) 2006-2008, Shawn O. Pearce <spearce@spearce.org>
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.eclipse.jgit.lib;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.MessageFormat;
import org.eclipse.jgit.JGitText;
import org.eclipse.jgit.errors.CorruptObjectException;
import org.eclipse.jgit.util.MutableInteger;
/** Misc. constants used throughout JGit. */
public final class Constants {
/** Hash function used natively by Git for all objects. */
private static final String HASH_FUNCTION = "SHA-1";
/**
* A Git object hash is 160 bits, i.e. 20 bytes.
* <p>
* Changing this assumption is not going to be as easy as changing this
* declaration.
*/
public static final int OBJECT_ID_LENGTH = 20;
/**
* A Git object can be expressed as a 40 character string of hexadecimal
* digits.
*
* @see #OBJECT_ID_LENGTH
*/
public static final int OBJECT_ID_STRING_LENGTH = OBJECT_ID_LENGTH * 2;
/** Special name for the "HEAD" symbolic-ref. */
public static final String HEAD = "HEAD";
/** Special name for the "FETCH_HEAD" symbolic-ref. */
public static final String FETCH_HEAD = "FETCH_HEAD";
/**
* Text string that identifies an object as a commit.
* <p>
* Commits connect trees into a string of project histories, where each
* commit is an assertion that the best way to continue is to use this other
* tree (set of files).
*/
public static final String TYPE_COMMIT = "commit";
/**
* Text string that identifies an object as a blob.
* <p>
* Blobs store whole file revisions. They are used for any user file, as
* well as for symlinks. Blobs form the bulk of any project's storage space.
*/
public static final String TYPE_BLOB = "blob";
/**
* Text string that identifies an object as a tree.
* <p>
* Trees attach object ids (hashes) to names and file modes. The normal use
* for a tree is to store a version of a directory and its contents.
*/
public static final String TYPE_TREE = "tree";
/**
* Text string that identifies an object as an annotated tag.
* <p>
* Annotated tags store a pointer to any other object, and an additional
* message. It is most commonly used to record a stable release of the
* project.
*/
public static final String TYPE_TAG = "tag";
private static final byte[] ENCODED_TYPE_COMMIT = encodeASCII(TYPE_COMMIT);
private static final byte[] ENCODED_TYPE_BLOB = encodeASCII(TYPE_BLOB);
private static final byte[] ENCODED_TYPE_TREE = encodeASCII(TYPE_TREE);
private static final byte[] ENCODED_TYPE_TAG = encodeASCII(TYPE_TAG);
/** An unknown or invalid object type code. */
public static final int OBJ_BAD = -1;
/**
* In-pack object type: extended types.
* <p>
* This header code is reserved for future expansion. It is currently
* undefined/unsupported.
*/
public static final int OBJ_EXT = 0;
/**
* In-pack object type: commit.
* <p>
* Indicates the associated object is a commit.
* <p>
* <b>This constant is fixed and is defined by the Git packfile format.</b>
*
* @see #TYPE_COMMIT
*/
public static final int OBJ_COMMIT = 1;
/**
* In-pack object type: tree.
* <p>
* Indicates the associated object is a tree.
* <p>
* <b>This constant is fixed and is defined by the Git packfile format.</b>
*
* @see #TYPE_BLOB
*/
public static final int OBJ_TREE = 2;
/**
* In-pack object type: blob.
* <p>
* Indicates the associated object is a blob.
* <p>
* <b>This constant is fixed and is defined by the Git packfile format.</b>
*
* @see #TYPE_BLOB
*/
public static final int OBJ_BLOB = 3;
/**
* In-pack object type: annotated tag.
* <p>
* Indicates the associated object is an annotated tag.
* <p>
* <b>This constant is fixed and is defined by the Git packfile format.</b>
*
* @see #TYPE_TAG
*/
public static final int OBJ_TAG = 4;
/** In-pack object type: reserved for future use. */
public static final int OBJ_TYPE_5 = 5;
/**
* In-pack object type: offset delta
* <p>
* Objects stored with this type actually have a different type which must
* be obtained from their delta base object. Delta objects store only the
* changes needed to apply to the base object in order to recover the
* original object.
* <p>
* An offset delta uses a negative offset from the start of this object to
* refer to its delta base. The base object must exist in this packfile
* (even in the case of a thin pack).
* <p>
* <b>This constant is fixed and is defined by the Git packfile format.</b>
*/
public static final int OBJ_OFS_DELTA = 6;
/**
* In-pack object type: reference delta
* <p>
* Objects stored with this type actually have a different type which must
* be obtained from their delta base object. Delta objects store only the
* changes needed to apply to the base object in order to recover the
* original object.
* <p>
* A reference delta uses a full object id (hash) to reference the delta
* base. The base object is allowed to be omitted from the packfile, but
* only in the case of a thin pack being transferred over the network.
* <p>
* <b>This constant is fixed and is defined by the Git packfile format.</b>
*/
public static final int OBJ_REF_DELTA = 7;
/**
* Pack file signature that occurs at file header - identifies file as Git
* packfile formatted.
* <p>
* <b>This constant is fixed and is defined by the Git packfile format.</b>
*/
public static final byte[] PACK_SIGNATURE = { 'P', 'A', 'C', 'K' };
/** Native character encoding for commit messages, file names... */
public static final String CHARACTER_ENCODING = "UTF-8";
/** Native character encoding for commit messages, file names... */
public static final Charset CHARSET;
/** Default main branch name */
public static final String MASTER = "master";
/** Default stash branch name */
public static final String STASH = "stash";
/** Prefix for branch refs */
public static final String R_HEADS = "refs/heads/";
/** Prefix for remotes refs */
public static final String R_REMOTES = "refs/remotes/";
/** Prefix for tag refs */
public static final String R_TAGS = "refs/tags/";
/** Prefix for notes refs */
public static final String R_NOTES = "refs/notes/";
/** Standard notes ref */
public static final String R_NOTES_COMMITS = R_NOTES + "commits";
/** Prefix for any ref */
public static final String R_REFS = "refs/";
/** Standard stash ref */
public static final String R_STASH = R_REFS + STASH;
/** Logs folder name */
public static final String LOGS = "logs";
/** Info refs folder */
public static final String INFO_REFS = "info/refs";
/** Packed refs file */
public static final String PACKED_REFS = "packed-refs";
/** The environment variable that contains the system user name */
public static final String OS_USER_NAME_KEY = "user.name";
/** The environment variable that contains the author's name */
public static final String GIT_AUTHOR_NAME_KEY = "GIT_AUTHOR_NAME";
/** The environment variable that contains the author's email */
public static final String GIT_AUTHOR_EMAIL_KEY = "GIT_AUTHOR_EMAIL";
/** The environment variable that contains the commiter's name */
public static final String GIT_COMMITTER_NAME_KEY = "GIT_COMMITTER_NAME";
/** The environment variable that contains the commiter's email */
public static final String GIT_COMMITTER_EMAIL_KEY = "GIT_COMMITTER_EMAIL";
/**
* The environment variable that limits how close to the root of the file
* systems JGit will traverse when looking for a repository root.
*/
public static final String GIT_CEILING_DIRECTORIES_KEY = "GIT_CEILING_DIRECTORIES";
/**
* The environment variable that tells us which directory is the ".git"
* directory
*/
public static final String GIT_DIR_KEY = "GIT_DIR";
/**
* The environment variable that tells us which directory is the working
* directory.
*/
public static final String GIT_WORK_TREE_KEY = "GIT_WORK_TREE";
/**
* The environment variable that tells us which file holds the Git index.
*/
public static final String GIT_INDEX_FILE_KEY = "GIT_INDEX_FILE";
/**
* The environment variable that tells us where objects are stored
*/
public static final String GIT_OBJECT_DIRECTORY_KEY = "GIT_OBJECT_DIRECTORY";
/**
* The environment variable that tells us where to look for objects, besides
* the default objects directory.
*/
public static final String GIT_ALTERNATE_OBJECT_DIRECTORIES_KEY = "GIT_ALTERNATE_OBJECT_DIRECTORIES";
/** Default value for the user name if no other information is available */
public static final String UNKNOWN_USER_DEFAULT = "unknown-user";
/** Beginning of the common "Signed-off-by: " commit message line */
public static final String SIGNED_OFF_BY_TAG = "Signed-off-by: ";
/** A gitignore file name */
public static final String GITIGNORE_FILENAME = ".gitignore";
/** Default remote name used by clone, push and fetch operations */
public static final String DEFAULT_REMOTE_NAME = "origin";
/** Default name for the Git repository directory */
public static final String DOT_GIT = ".git";
/** Default name for the Git repository configuration */
public static final String CONFIG = "config";
/** A bare repository typically ends with this string */
public static final String DOT_GIT_EXT = ".git";
/** Name of the ignore file */
public static final String DOT_GIT_IGNORE = ".gitignore";
/** Name of the submodules file */
public static final String DOT_GIT_MODULES = ".gitmodules";
/**
* Create a new digest function for objects.
*
* @return a new digest object.
* @throws RuntimeException
* this Java virtual machine does not support the required hash
* function. Very unlikely given that JGit uses a hash function
* that is in the Java reference specification.
*/
public static MessageDigest newMessageDigest() {
try {
return MessageDigest.getInstance(HASH_FUNCTION);
} catch (NoSuchAlgorithmException nsae) {
throw new RuntimeException(MessageFormat.format(
JGitText.get().requiredHashFunctionNotAvailable, HASH_FUNCTION), nsae);
}
}
/**
* Convert an OBJ_* type constant to a TYPE_* type constant.
*
* @param typeCode the type code, from a pack representation.
* @return the canonical string name of this type.
*/
public static String typeString(final int typeCode) {
switch (typeCode) {
case OBJ_COMMIT:
return TYPE_COMMIT;
case OBJ_TREE:
return TYPE_TREE;
case OBJ_BLOB:
return TYPE_BLOB;
case OBJ_TAG:
return TYPE_TAG;
default:
throw new IllegalArgumentException(MessageFormat.format(JGitText.get().badObjectType, typeCode));
}
}
/**
* Convert an OBJ_* type constant to an ASCII encoded string constant.
* <p>
* The ASCII encoded string is often the canonical representation of
* the type within a loose object header, or within a tag header.
*
* @param typeCode the type code, from a pack representation.
* @return the canonical ASCII encoded name of this type.
*/
public static byte[] encodedTypeString(final int typeCode) {
switch (typeCode) {
case OBJ_COMMIT:
return ENCODED_TYPE_COMMIT;
case OBJ_TREE:
return ENCODED_TYPE_TREE;
case OBJ_BLOB:
return ENCODED_TYPE_BLOB;
case OBJ_TAG:
return ENCODED_TYPE_TAG;
default:
throw new IllegalArgumentException(MessageFormat.format(JGitText.get().badObjectType, typeCode));
}
}
/**
* Parse an encoded type string into a type constant.
*
* @param id
* object id this type string came from; may be null if that is
* not known at the time the parse is occurring.
* @param typeString
* string version of the type code.
* @param endMark
* character immediately following the type string. Usually ' '
* (space) or '\n' (line feed).
* @param offset
* position within <code>typeString</code> where the parse
* should start. Updated with the new position (just past
* <code>endMark</code> when the parse is successful.
* @return a type code constant (one of {@link #OBJ_BLOB},
* {@link #OBJ_COMMIT}, {@link #OBJ_TAG}, {@link #OBJ_TREE}.
* @throws CorruptObjectException
* there is no valid type identified by <code>typeString</code>.
*/
public static int decodeTypeString(final AnyObjectId id,
final byte[] typeString, final byte endMark,
final MutableInteger offset) throws CorruptObjectException {
try {
int position = offset.value;
switch (typeString[position]) {
case 'b':
if (typeString[position + 1] != 'l'
|| typeString[position + 2] != 'o'
|| typeString[position + 3] != 'b'
|| typeString[position + 4] != endMark)
throw new CorruptObjectException(id, JGitText.get().corruptObjectInvalidType);
offset.value = position + 5;
return Constants.OBJ_BLOB;
case 'c':
if (typeString[position + 1] != 'o'
|| typeString[position + 2] != 'm'
|| typeString[position + 3] != 'm'
|| typeString[position + 4] != 'i'
|| typeString[position + 5] != 't'
|| typeString[position + 6] != endMark)
throw new CorruptObjectException(id, JGitText.get().corruptObjectInvalidType);
offset.value = position + 7;
return Constants.OBJ_COMMIT;
case 't':
switch (typeString[position + 1]) {
case 'a':
if (typeString[position + 2] != 'g'
|| typeString[position + 3] != endMark)
throw new CorruptObjectException(id, JGitText.get().corruptObjectInvalidType);
offset.value = position + 4;
return Constants.OBJ_TAG;
case 'r':
if (typeString[position + 2] != 'e'
|| typeString[position + 3] != 'e'
|| typeString[position + 4] != endMark)
throw new CorruptObjectException(id, JGitText.get().corruptObjectInvalidType);
offset.value = position + 5;
return Constants.OBJ_TREE;
default:
throw new CorruptObjectException(id, JGitText.get().corruptObjectInvalidType);
}
default:
throw new CorruptObjectException(id, JGitText.get().corruptObjectInvalidType);
}
} catch (ArrayIndexOutOfBoundsException bad) {
throw new CorruptObjectException(id, JGitText.get().corruptObjectInvalidType);
}
}
/**
* Convert an integer into its decimal representation.
*
* @param s
* the integer to convert.
* @return a decimal representation of the input integer. The returned array
* is the smallest array that will hold the value.
*/
public static byte[] encodeASCII(final long s) {
return encodeASCII(Long.toString(s));
}
/**
* Convert a string to US-ASCII encoding.
*
* @param s
* the string to convert. Must not contain any characters over
* 127 (outside of 7-bit ASCII).
* @return a byte array of the same length as the input string, holding the
* same characters, in the same order.
* @throws IllegalArgumentException
* the input string contains one or more characters outside of
* the 7-bit ASCII character space.
*/
public static byte[] encodeASCII(final String s) {
final byte[] r = new byte[s.length()];
for (int k = r.length - 1; k >= 0; k--) {
final char c = s.charAt(k);
if (c > 127)
throw new IllegalArgumentException(MessageFormat.format(JGitText.get().notASCIIString, s));
r[k] = (byte) c;
}
return r;
}
/**
* Convert a string to a byte array in the standard character encoding.
*
* @param str
* the string to convert. May contain any Unicode characters.
* @return a byte array representing the requested string, encoded using the
* default character encoding (UTF-8).
* @see #CHARACTER_ENCODING
*/
public static byte[] encode(final String str) {
final ByteBuffer bb = Constants.CHARSET.encode(str);
final int len = bb.limit();
if (bb.hasArray() && bb.arrayOffset() == 0) {
final byte[] arr = bb.array();
if (arr.length == len)
return arr;
}
final byte[] arr = new byte[len];
bb.get(arr);
return arr;
}
static {
if (OBJECT_ID_LENGTH != newMessageDigest().getDigestLength())
throw new LinkageError(JGitText.get().incorrectOBJECT_ID_LENGTH);
CHARSET = Charset.forName(CHARACTER_ENCODING);
}
/** name of the file containing the commit msg for a merge commit */
public static final String MERGE_MSG = "MERGE_MSG";
/** name of the file containing the IDs of the parents of a merge commit */
public static final String MERGE_HEAD = "MERGE_HEAD";
/** name of the file containing the ID of a cherry pick commit in case of conflicts */
public static final String CHERRY_PICK_HEAD = "CHERRY_PICK_HEAD";
/**
* name of the ref ORIG_HEAD used by certain commands to store the original
* value of HEAD
*/
public static final String ORIG_HEAD = "ORIG_HEAD";
/** objectid for the empty blob */
public static final ObjectId EMPTY_BLOB_ID = ObjectId
.fromString("e69de29bb2d1d6434b8b29ae775ad8c2e48c5391");
private Constants() {
// Hide the default constructor
}
}