| /* |
| * Copyright (C) 2008-2009, Google Inc. and others |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0 which is available at |
| * https://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| package org.eclipse.jgit.lib; |
| |
| import java.io.Serializable; |
| import java.text.MessageFormat; |
| |
| import org.eclipse.jgit.errors.InvalidObjectIdException; |
| import org.eclipse.jgit.internal.JGitText; |
| import org.eclipse.jgit.util.NB; |
| import org.eclipse.jgit.util.RawParseUtils; |
| |
| /** |
| * A prefix abbreviation of an {@link org.eclipse.jgit.lib.ObjectId}. |
| * <p> |
| * Sometimes Git produces abbreviated SHA-1 strings, using sufficient leading |
| * digits from the ObjectId name to still be unique within the repository the |
| * string was generated from. These ids are likely to be unique for a useful |
| * period of time, especially if they contain at least 6-10 hex digits. |
| * <p> |
| * This class converts the hex string into a binary form, to make it more |
| * efficient for matching against an object. |
| */ |
| public final class AbbreviatedObjectId implements Serializable { |
| private static final long serialVersionUID = 1L; |
| |
| /** |
| * Test a string of characters to verify it is a hex format. |
| * <p> |
| * If true the string can be parsed with {@link #fromString(String)}. |
| * |
| * @param id |
| * the string to test. |
| * @return true if the string can converted into an AbbreviatedObjectId. |
| */ |
| public static final boolean isId(String id) { |
| if (id.length() < 2 || Constants.OBJECT_ID_STRING_LENGTH < id.length()) |
| return false; |
| try { |
| for (int i = 0; i < id.length(); i++) |
| RawParseUtils.parseHexInt4((byte) id.charAt(i)); |
| return true; |
| } catch (ArrayIndexOutOfBoundsException e) { |
| return false; |
| } |
| } |
| |
| /** |
| * Convert an AbbreviatedObjectId from hex characters (US-ASCII). |
| * |
| * @param buf |
| * the US-ASCII buffer to read from. |
| * @param offset |
| * position to read the first character from. |
| * @param end |
| * one past the last position to read (<code>end-offset</code> is |
| * the length of the string). |
| * @return the converted object id. |
| */ |
| public static final AbbreviatedObjectId fromString(final byte[] buf, |
| final int offset, final int end) { |
| if (end - offset > Constants.OBJECT_ID_STRING_LENGTH) |
| throw new IllegalArgumentException(MessageFormat.format( |
| JGitText.get().invalidIdLength, |
| Integer.valueOf(end - offset), |
| Integer.valueOf(Constants.OBJECT_ID_STRING_LENGTH))); |
| return fromHexString(buf, offset, end); |
| } |
| |
| /** |
| * Convert an AbbreviatedObjectId from an |
| * {@link org.eclipse.jgit.lib.AnyObjectId}. |
| * <p> |
| * This method copies over all bits of the Id, and is therefore complete |
| * (see {@link #isComplete()}). |
| * |
| * @param id |
| * the {@link org.eclipse.jgit.lib.ObjectId} to convert from. |
| * @return the converted object id. |
| */ |
| public static final AbbreviatedObjectId fromObjectId(AnyObjectId id) { |
| return new AbbreviatedObjectId(Constants.OBJECT_ID_STRING_LENGTH, |
| id.w1, id.w2, id.w3, id.w4, id.w5); |
| } |
| |
| /** |
| * Convert an AbbreviatedObjectId from hex characters. |
| * |
| * @param str |
| * the string to read from. Must be <= 40 characters. |
| * @return the converted object id. |
| */ |
| public static final AbbreviatedObjectId fromString(String str) { |
| if (str.length() > Constants.OBJECT_ID_STRING_LENGTH) |
| throw new IllegalArgumentException(MessageFormat.format(JGitText.get().invalidId, str)); |
| final byte[] b = Constants.encodeASCII(str); |
| return fromHexString(b, 0, b.length); |
| } |
| |
| private static final AbbreviatedObjectId fromHexString(final byte[] bs, |
| int ptr, final int end) { |
| try { |
| final int a = hexUInt32(bs, ptr, end); |
| final int b = hexUInt32(bs, ptr + 8, end); |
| final int c = hexUInt32(bs, ptr + 16, end); |
| final int d = hexUInt32(bs, ptr + 24, end); |
| final int e = hexUInt32(bs, ptr + 32, end); |
| return new AbbreviatedObjectId(end - ptr, a, b, c, d, e); |
| } catch (ArrayIndexOutOfBoundsException e) { |
| InvalidObjectIdException e1 = new InvalidObjectIdException(bs, ptr, |
| end - ptr); |
| e1.initCause(e); |
| throw e1; |
| } |
| } |
| |
| private static final int hexUInt32(final byte[] bs, int p, final int end) { |
| if (8 <= end - p) |
| return RawParseUtils.parseHexInt32(bs, p); |
| |
| int r = 0, n = 0; |
| while (n < 8 && p < end) { |
| r <<= 4; |
| r |= RawParseUtils.parseHexInt4(bs[p++]); |
| n++; |
| } |
| return r << ((8 - n) * 4); |
| } |
| |
| static int mask(int nibbles, int word, int v) { |
| final int b = (word - 1) * 8; |
| if (b + 8 <= nibbles) { |
| // We have all of the bits required for this word. |
| // |
| return v; |
| } |
| |
| if (nibbles <= b) { |
| // We have none of the bits required for this word. |
| // |
| return 0; |
| } |
| |
| final int s = 32 - (nibbles - b) * 4; |
| return (v >>> s) << s; |
| } |
| |
| /** Number of half-bytes used by this id. */ |
| final int nibbles; |
| |
| final int w1; |
| |
| final int w2; |
| |
| final int w3; |
| |
| final int w4; |
| |
| final int w5; |
| |
| AbbreviatedObjectId(final int n, final int new_1, final int new_2, |
| final int new_3, final int new_4, final int new_5) { |
| nibbles = n; |
| w1 = new_1; |
| w2 = new_2; |
| w3 = new_3; |
| w4 = new_4; |
| w5 = new_5; |
| } |
| |
| /** |
| * Get number of hex digits appearing in this id. |
| * |
| * @return number of hex digits appearing in this id. |
| */ |
| public int length() { |
| return nibbles; |
| } |
| |
| /** |
| * Whether this ObjectId is actually a complete id. |
| * |
| * @return true if this ObjectId is actually a complete id. |
| */ |
| public boolean isComplete() { |
| return length() == Constants.OBJECT_ID_STRING_LENGTH; |
| } |
| |
| /** |
| * A complete ObjectId; null if {@link #isComplete()} is false |
| * |
| * @return a complete ObjectId; null if {@link #isComplete()} is false |
| */ |
| public ObjectId toObjectId() { |
| return isComplete() ? new ObjectId(w1, w2, w3, w4, w5) : null; |
| } |
| |
| /** |
| * Compares this abbreviation to a full object id. |
| * |
| * @param other |
| * the other object id. |
| * @return <0 if this abbreviation names an object that is less than |
| * <code>other</code>; 0 if this abbreviation exactly matches the |
| * first {@link #length()} digits of <code>other.name()</code>; |
| * >0 if this abbreviation names an object that is after |
| * <code>other</code>. |
| */ |
| public final int prefixCompare(AnyObjectId other) { |
| int cmp; |
| |
| cmp = NB.compareUInt32(w1, mask(1, other.w1)); |
| if (cmp != 0) |
| return cmp; |
| |
| cmp = NB.compareUInt32(w2, mask(2, other.w2)); |
| if (cmp != 0) |
| return cmp; |
| |
| cmp = NB.compareUInt32(w3, mask(3, other.w3)); |
| if (cmp != 0) |
| return cmp; |
| |
| cmp = NB.compareUInt32(w4, mask(4, other.w4)); |
| if (cmp != 0) |
| return cmp; |
| |
| return NB.compareUInt32(w5, mask(5, other.w5)); |
| } |
| |
| /** |
| * Compare this abbreviation to a network-byte-order ObjectId. |
| * |
| * @param bs |
| * array containing the other ObjectId in network byte order. |
| * @param p |
| * position within {@code bs} to start the compare at. At least |
| * 20 bytes, starting at this position are required. |
| * @return <0 if this abbreviation names an object that is less than |
| * <code>other</code>; 0 if this abbreviation exactly matches the |
| * first {@link #length()} digits of <code>other.name()</code>; |
| * >0 if this abbreviation names an object that is after |
| * <code>other</code>. |
| */ |
| public final int prefixCompare(byte[] bs, int p) { |
| int cmp; |
| |
| cmp = NB.compareUInt32(w1, mask(1, NB.decodeInt32(bs, p))); |
| if (cmp != 0) |
| return cmp; |
| |
| cmp = NB.compareUInt32(w2, mask(2, NB.decodeInt32(bs, p + 4))); |
| if (cmp != 0) |
| return cmp; |
| |
| cmp = NB.compareUInt32(w3, mask(3, NB.decodeInt32(bs, p + 8))); |
| if (cmp != 0) |
| return cmp; |
| |
| cmp = NB.compareUInt32(w4, mask(4, NB.decodeInt32(bs, p + 12))); |
| if (cmp != 0) |
| return cmp; |
| |
| return NB.compareUInt32(w5, mask(5, NB.decodeInt32(bs, p + 16))); |
| } |
| |
| /** |
| * Compare this abbreviation to a network-byte-order ObjectId. |
| * |
| * @param bs |
| * array containing the other ObjectId in network byte order. |
| * @param p |
| * position within {@code bs} to start the compare at. At least 5 |
| * ints, starting at this position are required. |
| * @return <0 if this abbreviation names an object that is less than |
| * <code>other</code>; 0 if this abbreviation exactly matches the |
| * first {@link #length()} digits of <code>other.name()</code>; |
| * >0 if this abbreviation names an object that is after |
| * <code>other</code>. |
| */ |
| public final int prefixCompare(int[] bs, int p) { |
| int cmp; |
| |
| cmp = NB.compareUInt32(w1, mask(1, bs[p])); |
| if (cmp != 0) |
| return cmp; |
| |
| cmp = NB.compareUInt32(w2, mask(2, bs[p + 1])); |
| if (cmp != 0) |
| return cmp; |
| |
| cmp = NB.compareUInt32(w3, mask(3, bs[p + 2])); |
| if (cmp != 0) |
| return cmp; |
| |
| cmp = NB.compareUInt32(w4, mask(4, bs[p + 3])); |
| if (cmp != 0) |
| return cmp; |
| |
| return NB.compareUInt32(w5, mask(5, bs[p + 4])); |
| } |
| |
| /** |
| * Get value for a fan-out style map, only valid of length >= 2. |
| * |
| * @return value for a fan-out style map, only valid of length >= 2. |
| */ |
| public final int getFirstByte() { |
| return w1 >>> 24; |
| } |
| |
| private int mask(int word, int v) { |
| return mask(nibbles, word, v); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public int hashCode() { |
| return w1; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public boolean equals(Object o) { |
| if (o instanceof AbbreviatedObjectId) { |
| final AbbreviatedObjectId b = (AbbreviatedObjectId) o; |
| return nibbles == b.nibbles && w1 == b.w1 && w2 == b.w2 |
| && w3 == b.w3 && w4 == b.w4 && w5 == b.w5; |
| } |
| return false; |
| } |
| |
| /** |
| * Get string form of the abbreviation, in lower case hexadecimal. |
| * |
| * @return string form of the abbreviation, in lower case hexadecimal. |
| */ |
| public final String name() { |
| final char[] b = new char[Constants.OBJECT_ID_STRING_LENGTH]; |
| |
| AnyObjectId.formatHexChar(b, 0, w1); |
| if (nibbles <= 8) |
| return new String(b, 0, nibbles); |
| |
| AnyObjectId.formatHexChar(b, 8, w2); |
| if (nibbles <= 16) |
| return new String(b, 0, nibbles); |
| |
| AnyObjectId.formatHexChar(b, 16, w3); |
| if (nibbles <= 24) |
| return new String(b, 0, nibbles); |
| |
| AnyObjectId.formatHexChar(b, 24, w4); |
| if (nibbles <= 32) |
| return new String(b, 0, nibbles); |
| |
| AnyObjectId.formatHexChar(b, 32, w5); |
| return new String(b, 0, nibbles); |
| } |
| |
| /** {@inheritDoc} */ |
| @SuppressWarnings("nls") |
| @Override |
| public String toString() { |
| return "AbbreviatedObjectId[" + name() + "]"; //$NON-NLS-1$ |
| } |
| } |