Mercurial > hg4j

annotate src/com/tmate/hgkit/fs/DataAccess.java @ 159:f5aed108754e wrap-data-access

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Approach with DataAccess instead of plain byte[] was merged into default branch
author Artem Tikhomirov <tikhomirov.artem@gmail.com>
date Wed, 09 Mar 2011 13:28:02 +0100
parents 9429c7bd1920
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 }