SocketInputBuffer.java revision e30b5b55806b31d1a61e2885b854dd7b8da1a07a 
1/*
2 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/impl/io/SocketInputBuffer.java $
3 * $Revision: 560358 $
4 * $Date: 2007-07-27 12:30:42 -0700 (Fri, 27 Jul 2007) $
5 *
6 * ====================================================================
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements.  See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership.  The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with the License.  You may obtain a copy of the License at
14 *
15 *   http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied.  See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 * ====================================================================
24 *
25 * This software consists of voluntary contributions made by many
26 * individuals on behalf of the Apache Software Foundation.  For more
27 * information on the Apache Software Foundation, please see
28 * <http://www.apache.org/>.
29 *
30 */
31
32package org.apache.http.impl.io;
33
34import java.io.IOException;
35import java.io.InterruptedIOException;
36import java.net.Socket;
37import java.net.SocketTimeoutException;
38
39import java.net.SocketTimeoutException;
40import org.apache.http.params.HttpParams;
41
42
43/**
44 * {@link Socket} bound session input buffer.
45 *
46 * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
47 *
48 * @version $Revision: 560358 $
49 *
50 * @since 4.0
51 */
52public class SocketInputBuffer extends AbstractSessionInputBuffer {
53
54    private final Socket socket;
55
56    public SocketInputBuffer(
57            final Socket socket,
58            int buffersize,
59            final HttpParams params) throws IOException {
60        super();
61        if (socket == null) {
62            throw new IllegalArgumentException("Socket may not be null");
63        }
64        this.socket = socket;
65        // BEGIN android-changed
66        // Workaround for http://b/3514259. We take 'buffersize' as a hint in
67        // the weakest sense, and always use an 8KiB heap buffer and leave the
68        // kernel buffer size alone, trusting the system to have set a
69        // network-appropriate default.
70        init(socket.getInputStream(), 8192, params);
71        // END android-changed
72    }
73
74    public boolean isDataAvailable(int timeout) throws IOException {
75        boolean result = hasBufferedData();
76        if (!result) {
77            int oldtimeout = this.socket.getSoTimeout();
78            try {
79                this.socket.setSoTimeout(timeout);
80                fillBuffer();
81                result = hasBufferedData();
82            } catch (InterruptedIOException e) {
83                if (!(e instanceof SocketTimeoutException)) {
84                    throw e;
85                }
86            } finally {
87                socket.setSoTimeout(oldtimeout);
88            }
89        }
90        return result;
91    }
92
93    // BEGIN android-added
94    /**
95     * Returns true if the connection is probably functional. It's insufficient
96     * to rely on isDataAvailable() returning normally; that approach cannot
97     * distinguish between an exhausted stream and a stream with zero bytes
98     * buffered.
99     *
100     * @hide
101     */
102    public boolean isStale() throws IOException {
103        if (hasBufferedData()) {
104            return false;
105        }
106        int oldTimeout = this.socket.getSoTimeout();
107        try {
108            this.socket.setSoTimeout(1);
109            return fillBuffer() == -1;
110        } catch (SocketTimeoutException e) {
111            return false; // the connection is not stale; hooray
112        } catch (IOException e) {
113            return true; // the connection is stale, the read or soTimeout failed.
114        } finally {
115            this.socket.setSoTimeout(oldTimeout);
116        }
117    }
118    // END android-added
119}
120