1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
|
/*******************************************************************************
* Copyright (c) 2008-2010 Sonatype, Inc.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Sonatype, Inc. - initial API and implementation
*******************************************************************************/
package org.eclipse.m2e.core.internal.builder;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import org.sonatype.plexus.build.incremental.BuildContext;
/**
* Writes to the file only if content of the file is different.
*
* TODO. Current implementation defers actual writing to the output file until
* invocation of {@link #close()} method. This results in missed/ignored IOExceptions
* in some cases. First, {@link #flush()} method does not actually flush buffer to the disk.
* Second, any problems writing to the file will be reported as IOException
* thrown by {@link #close()}, which are generally ignored.
*/
public class ChangedFileOutputStream extends OutputStream {
private final File file;
private final BuildContext buildContext;
private final OutputStream os;
private ByteArrayOutputStream buffer = new ByteArrayOutputStream();
public ChangedFileOutputStream(File file) throws FileNotFoundException {
this(file, null);
}
public ChangedFileOutputStream(File file, BuildContext buildContext) throws FileNotFoundException {
this.file = file;
this.buildContext = buildContext;
this.os = new BufferedOutputStream(new FileOutputStream(file));
}
public void write(int b) {
buffer.write(b);
}
public void write(byte[] b, int off, int len) {
buffer.write(b, off, len);
}
public void close() throws IOException {
try {
writeIfNewOrChanged();
} finally {
os.close();
}
}
protected void writeIfNewOrChanged() throws IOException {
byte[] bytes = buffer.toByteArray();
boolean needToWrite = false;
// XXX harden
if (file.exists()) {
BufferedInputStream is = new BufferedInputStream(new FileInputStream(file));
try {
for (int i = 0; i < bytes.length; i++) {
if (bytes[i] != is.read()) {
needToWrite = true;
break;
}
}
} finally {
try {
is.close();
} catch (IOException e) {
}
}
} else {
// file does not exist
needToWrite = true;
}
if (needToWrite) {
if (buildContext != null) {
buildContext.refresh(file);
}
os.write(bytes);
}
}
}
|
