1 /*
2 * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23 package jdk.incubator.http.internal.hpack;
24
25 import java.nio.ByteBuffer;
26 import java.util.*;
27 import java.util.function.Consumer;
28 import java.util.function.Function;
29 import java.util.function.Supplier;
30
31 import static java.nio.ByteBuffer.allocate;
32
33 public final class BuffersTestingKit {
34
35 /**
36 * Relocates a {@code [position, limit)} region of the given buffer to
37 * corresponding region in a new buffer starting with provided {@code
38 * newPosition}.
39 *
40 * <p> Might be useful to make sure ByteBuffer's users do not rely on any
41 * absolute positions, but solely on what's reported by position(), limit().
42 *
43 * <p> The contents between the given buffer and the returned one are not
44 * shared.
45 */
46 public static ByteBuffer relocate(ByteBuffer buffer, int newPosition,
47 int newCapacity) {
48 int oldPosition = buffer.position();
49 int oldLimit = buffer.limit();
50
51 if (newPosition + oldLimit - oldPosition > newCapacity) {
52 throw new IllegalArgumentException();
53 }
54
55 ByteBuffer result;
56 if (buffer.isDirect()) {
57 result = ByteBuffer.allocateDirect(newCapacity);
58 } else {
59 result = allocate(newCapacity);
60 }
61
62 result.position(newPosition);
63 result.put(buffer).limit(result.position()).position(newPosition);
64 buffer.position(oldPosition);
65
66 if (buffer.isReadOnly()) {
67 return result.asReadOnlyBuffer();
68 }
69 return result;
70 }
71
72 public static Iterable<? extends ByteBuffer> relocateBuffers(
73 Iterable<? extends ByteBuffer> source) {
74 return () ->
75 new Iterator<ByteBuffer>() {
76
77 private final Iterator<? extends ByteBuffer> it = source.iterator();
78
79 @Override
80 public boolean hasNext() {
81 return it.hasNext();
82 }
83
84 @Override
85 public ByteBuffer next() {
86 ByteBuffer buf = it.next();
87 int remaining = buf.remaining();
88 int newCapacity = remaining + random.nextInt(17);
89 int newPosition = random.nextInt(newCapacity - remaining + 1);
90 return relocate(buf, newPosition, newCapacity);
91 }
92 };
93 }
94
95 // TODO: not always of size 0 (it's fine for buffer to report !b.hasRemaining())
96 public static Iterable<? extends ByteBuffer> injectEmptyBuffers(
97 Iterable<? extends ByteBuffer> source) {
98 return injectEmptyBuffers(source, () -> allocate(0));
99 }
100
101 public static Iterable<? extends ByteBuffer> injectEmptyBuffers(
102 Iterable<? extends ByteBuffer> source,
103 Supplier<? extends ByteBuffer> emptyBufferFactory) {
104
105 return () ->
106 new Iterator<ByteBuffer>() {
107
108 private final Iterator<? extends ByteBuffer> it = source.iterator();
109 private ByteBuffer next = calculateNext();
110
111 private ByteBuffer calculateNext() {
112 if (random.nextBoolean()) {
113 return emptyBufferFactory.get();
114 } else if (it.hasNext()) {
115 return it.next();
116 } else {
117 return null;
118 }
119 }
120
121 @Override
122 public boolean hasNext() {
123 return next != null;
124 }
125
126 @Override
127 public ByteBuffer next() {
128 if (!hasNext()) {
129 throw new NoSuchElementException();
130 }
131 ByteBuffer next = this.next;
132 this.next = calculateNext();
133 return next;
134 }
135 };
136 }
137
138 public static ByteBuffer concat(Iterable<? extends ByteBuffer> split) {
139 return concat(split, ByteBuffer::allocate);
140 }
141
142 public static ByteBuffer concat(Iterable<? extends ByteBuffer> split,
143 Function<? super Integer, ? extends ByteBuffer> concatBufferFactory) {
144 int size = 0;
145 for (ByteBuffer bb : split) {
146 size += bb.remaining();
147 }
148
149 ByteBuffer result = concatBufferFactory.apply(size);
150 for (ByteBuffer bb : split) {
151 result.put(bb);
152 }
153
154 result.flip();
155 return result;
156 }
157
158 public static void forEachSplit(ByteBuffer bb,
159 Consumer<? super Iterable<? extends ByteBuffer>> action) {
160 forEachSplit(bb.remaining(),
161 (lengths) -> {
162 int end = bb.position();
163 List<ByteBuffer> buffers = new LinkedList<>();
164 for (int len : lengths) {
165 ByteBuffer d = bb.duplicate();
166 d.position(end);
167 d.limit(end + len);
168 end += len;
169 buffers.add(d);
170 }
171 action.accept(buffers);
172 });
173 }
174
175 private static void forEachSplit(int n, Consumer<? super Iterable<? extends Integer>> action) {
176 forEachSplit(n, new Stack<>(), action);
177 }
178
179 private static void forEachSplit(int n, Stack<Integer> path,
180 Consumer<? super Iterable<? extends Integer>> action) {
181 if (n == 0) {
182 action.accept(path);
183 } else {
184 for (int i = 1; i <= n; i++) {
185 path.push(i);
186 forEachSplit(n - i, path, action);
187 path.pop();
188 }
189 }
190 }
191
192 private static final Random random = new Random();
193
194 private BuffersTestingKit() {
195 throw new InternalError();
196 }
197
198 // public static void main(String[] args) {
199 //
200 // List<ByteBuffer> buffers = Arrays.asList(
201 // (ByteBuffer) allocate(3).position(1).limit(2),
202 // allocate(0),
203 // allocate(7));
204 //
205 // Iterable<? extends ByteBuffer> buf = relocateBuffers(injectEmptyBuffers(buffers));
206 // List<ByteBuffer> result = new ArrayList<>();
207 // buf.forEach(result::add);
208 // System.out.println(result);
209 // }
210 }