Mercurial > hg4j

annotate src/com/tmate/hgkit/fs/DataAccess.java @ 51:9429c7bd1920 wrap-data-access

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Try DataAccess to reach revision data instead of plain byte arrays
author Artem Tikhomirov <tikhomirov.artem@gmail.com>
date Sun, 16 Jan 2011 01:20:26 +0100
parents 382cfe9463db
children
rev   line source
10
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
1 /*
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
2 * Copyright (c) 2010 Artem Tikhomirov
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
3 */
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
4 package com.tmate.hgkit.fs;
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
5
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
6 import java.io.IOException;
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
7
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
8 /**
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
9 * relevant parts of DataInput, non-stream nature (seek operation), explicit check for end of data.
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
10 * convenient skip (+/- bytes)
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
11 * Primary goal - effective file read, so that clients don't need to care whether to call few
51
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
12 * distinct getInt() or readBytes(totalForFewInts) and parse themselves instead in an attempt to optimize.
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
13 * Name: ByteSource? DataSource, DataInput, ByteInput
10
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
14 */
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
15 public class DataAccess {
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
16 public boolean isEmpty() {
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
17 return true;
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
18 }
51
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
19 public long length() {
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
20 return 0;
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
21 }
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
22 // get this instance into initial state
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
23 public void reset() throws IOException {
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
24 // nop, empty instance is always in the initial state
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
25 }
10
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
26 // absolute positioning
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
27 public void seek(long offset) throws IOException {
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
28 throw new UnsupportedOperationException();
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
29 }
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
30 // relative positioning
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
31 public void skip(int bytes) throws IOException {
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
32 throw new UnsupportedOperationException();
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
33 }
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
34 // shall be called once this object no longer needed
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
35 public void done() {
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
36 // no-op in this empty implementation
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
37 }
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
38 public int readInt() throws IOException {
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
39 byte[] b = new byte[4];
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
40 readBytes(b, 0, 4);
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
41 return b[0] << 24 | (b[1] & 0xFF) << 16 | (b[2] & 0xFF) << 8 | (b[3] & 0xFF);
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
42 }
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
43 public long readLong() throws IOException {
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
44 byte[] b = new byte[8];
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
45 readBytes(b, 0, 8);
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
46 int i1 = b[0] << 24 | (b[1] & 0xFF) << 16 | (b[2] & 0xFF) << 8 | (b[3] & 0xFF);
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
47 int i2 = b[4] << 24 | (b[5] & 0xFF) << 16 | (b[6] & 0xFF) << 8 | (b[7] & 0xFF);
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
48 return ((long) i1) << 32 | ((long) i2 & 0xFFFFFFFF);
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
49 }
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
50 public void readBytes(byte[] buf, int offset, int length) throws IOException {
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
51 throw new UnsupportedOperationException();
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
52 }
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
53 public byte readByte() throws IOException {
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
54 throw new UnsupportedOperationException();
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
55 }
51
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
56
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
57 // XXX decide whether may or may not change position in the DataAccess
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
58 // FIXME exception handling is not right, just for the sake of quick test
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
59 public byte[] byteArray() {
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
60 byte[] rv = new byte[(int) length()];
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
61 try {
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
62 reset();
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
63 readBytes(rv, 0, rv.length);
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
64 } catch (IOException ex) {
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
65 ex.printStackTrace();
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
66 }
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
67 return rv;
9429c7bd1920 Try DataAccess to reach revision data instead of plain byte arrays
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents: 10
diff changeset
68 }
10
382cfe9463db Dirstate parsing. DataAccess refactored to allow reuse and control over constants
Artem Tikhomirov <tikhomirov.artem@gmail.com>
parents:
diff changeset
69 }