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1 /*
2  * Copyright (C) 2010 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef NET_FD_H_included
18 #define NET_FD_H_included
19 
20 /**
21  * Wraps access to the int inside a java.io.FileDescriptor, taking care of throwing exceptions.
22  */
23 class NetFd {
24 public:
NetFd(JNIEnv * env,jobject fileDescriptor)25     NetFd(JNIEnv* env, jobject fileDescriptor)
26         : mEnv(env), mFileDescriptor(fileDescriptor), mFd(-1)
27     {
28     }
29 
isClosed()30     bool isClosed() {
31         mFd = jniGetFDFromFileDescriptor(mEnv, mFileDescriptor);
32         bool closed = (mFd == -1);
33         if (closed) {
34             jniThrowException(mEnv, "java/net/SocketException", "Socket closed");
35         }
36         return closed;
37     }
38 
get()39     int get() const {
40         return mFd;
41     }
42 
43 private:
44     JNIEnv* mEnv;
45     jobject mFileDescriptor;
46     int mFd;
47 
48     // Disallow copy and assignment.
49     NetFd(const NetFd&);
50     void operator=(const NetFd&);
51 };
52 
53 /**
54  * Used to retry syscalls that can return EINTR. This differs from TEMP_FAILURE_RETRY in that
55  * it also considers the case where the reason for failure is that another thread called
56  * Socket.close.
57  */
58 #define NET_FAILURE_RETRY(fd, exp) ({               \
59     typeof (exp) _rc;                               \
60     do {                                            \
61         _rc = (exp);                                \
62         if (_rc == -1) {                            \
63             if (fd.isClosed() || errno != EINTR) {  \
64                 break;                              \
65             }                                       \
66         }                                           \
67     } while (_rc == -1);                            \
68     _rc; })
69 
70 #endif // NET_FD_H_included
71