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 
26 package sun.nio.ch;
27 
28 import java.nio.ByteBuffer;
29 import sun.misc.*;
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 
44 class 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;
Deallocator(AllocatedNativeObject obj)73         Deallocator(AllocatedNativeObject obj) {
74             this.obj = obj;
75         }
run()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 
IOVecWrapper(int size)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 
get(int size)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             Cleaner.create(wrapper, new Deallocator(wrapper.vecArray));
105             cached.set(wrapper);
106         }
107         return wrapper;
108     }
109 
setBuffer(int i, ByteBuffer buf, int pos, int rem)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 
setShadow(int i, ByteBuffer buf)116     void setShadow(int i, ByteBuffer buf) {
117         shadow[i] = buf;
118     }
119 
getBuffer(int i)120     ByteBuffer getBuffer(int i) {
121         return buf[i];
122     }
123 
getPosition(int i)124     int getPosition(int i) {
125         return position[i];
126     }
127 
getRemaining(int i)128     int getRemaining(int i) {
129         return remaining[i];
130     }
131 
getShadow(int i)132     ByteBuffer getShadow(int i) {
133         return shadow[i];
134     }
135 
clearRefs(int i)136     void clearRefs(int i) {
137         buf[i] = null;
138         shadow[i] = null;
139     }
140 
putBase(int i, long base)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 
putLen(int i, long len)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