1/*
2 * Copyright (c) 2000, 2010, 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package sun.nio.ch;
27
28import java.nio.ByteBuffer;
29import jdk.internal.ref.CleanerFactory;
30
31
32/**
33 * Manipulates a native array of iovec structs on Solaris:
34 *
35 * typedef struct iovec {
36 *    caddr_t  iov_base;
37      int      iov_len;
38 * } iovec_t;
39 *
40 * @author Mike McCloskey
41 * @since 1.4
42 */
43
44class IOVecWrapper {
45
46    // Miscellaneous constants
47    private static final int BASE_OFFSET = 0;
48    private static final int LEN_OFFSET;
49    private static final int SIZE_IOVEC;
50
51    // The iovec array
52    private final AllocatedNativeObject vecArray;
53
54    // Number of elements in iovec array
55    private final int size;
56
57    // Buffers and position/remaining corresponding to elements in iovec array
58    private final ByteBuffer[] buf;
59    private final int[] position;
60    private final int[] remaining;
61
62    // Shadow buffers for cases when original buffer is substituted
63    private final ByteBuffer[] shadow;
64
65    // Base address of this array
66    final long address;
67
68    // Address size in bytes
69    static int addressSize;
70
71    private static class Deallocator implements Runnable {
72        private final AllocatedNativeObject obj;
73        Deallocator(AllocatedNativeObject obj) {
74            this.obj = obj;
75        }
76        public void run() {
77            obj.free();
78        }
79    }
80
81    // per thread IOVecWrapper
82    private static final ThreadLocal<IOVecWrapper> cached =
83        new ThreadLocal<IOVecWrapper>();
84
85    private IOVecWrapper(int size) {
86        this.size      = size;
87        this.buf       = new ByteBuffer[size];
88        this.position  = new int[size];
89        this.remaining = new int[size];
90        this.shadow    = new ByteBuffer[size];
91        this.vecArray  = new AllocatedNativeObject(size * SIZE_IOVEC, false);
92        this.address   = vecArray.address();
93    }
94
95    static IOVecWrapper get(int size) {
96        IOVecWrapper wrapper = cached.get();
97        if (wrapper != null && wrapper.size < size) {
98            // not big enough; eagerly release memory
99            wrapper.vecArray.free();
100            wrapper = null;
101        }
102        if (wrapper == null) {
103            wrapper = new IOVecWrapper(size);
104            CleanerFactory.cleaner().register(wrapper, new Deallocator(wrapper.vecArray));
105            cached.set(wrapper);
106        }
107        return wrapper;
108    }
109
110    void setBuffer(int i, ByteBuffer buf, int pos, int rem) {
111        this.buf[i] = buf;
112        this.position[i] = pos;
113        this.remaining[i] = rem;
114    }
115
116    void setShadow(int i, ByteBuffer buf) {
117        shadow[i] = buf;
118    }
119
120    ByteBuffer getBuffer(int i) {
121        return buf[i];
122    }
123
124    int getPosition(int i) {
125        return position[i];
126    }
127
128    int getRemaining(int i) {
129        return remaining[i];
130    }
131
132    ByteBuffer getShadow(int i) {
133        return shadow[i];
134    }
135
136    void clearRefs(int i) {
137        buf[i] = null;
138        shadow[i] = null;
139    }
140
141    void putBase(int i, long base) {
142        int offset = SIZE_IOVEC * i + BASE_OFFSET;
143        if (addressSize == 4)
144            vecArray.putInt(offset, (int)base);
145        else
146            vecArray.putLong(offset, base);
147    }
148
149    void putLen(int i, long len) {
150        int offset = SIZE_IOVEC * i + LEN_OFFSET;
151        if (addressSize == 4)
152            vecArray.putInt(offset, (int)len);
153        else
154            vecArray.putLong(offset, len);
155    }
156
157    static {
158        addressSize = Util.unsafe().addressSize();
159        LEN_OFFSET = addressSize;
160        SIZE_IOVEC = (short) (addressSize * 2);
161    }
162}
163