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 #ifndef ANDROID_ASYNC_UTILS_H
17 #define ANDROID_ASYNC_UTILS_H
18
19 #include "android/looper.h"
20 #include "sockets.h"
21
22 /* A set of useful data types to perform asynchronous operations.
23 *
24 * IMPORTANT NOTE:
25 * In case of network disconnection, read() and write() just return 0
26 * the first time they are called. As a convenience, these functions
27 * will return ASYNC_ERROR and set 'errno' to ECONNRESET instead.
28 */
29 typedef enum {
30 ASYNC_COMPLETE = 0, /* asynchronous operation completed */
31 ASYNC_ERROR, /* an error occurred, look at errno */
32 ASYNC_NEED_MORE /* more data is needed, try again later */
33 } AsyncStatus;
34
35 /**************************************************************************
36 **************************************************************************
37 *****
38 ***** A S Y N C R E A D E R
39 *****
40 *****/
41
42 /* An AsyncReader makes it easier to read a given number of bytes into
43 * a target buffer asynchronously. Usage is the following:
44 *
45 * 1/ setup the reader with asyncReader_init(ar, buffer, buffsize,io);
46 * 2/ call asyncReader_read(ar, io), where 'io' is a LoopIo whenever
47 * you can receive data, i.e. just after the init() or in your
48 * own callback.
49 */
50 typedef struct {
51 uint8_t* buffer;
52 size_t buffsize;
53 size_t pos;
54 LoopIo* io;
55 } AsyncReader;
56
57 /* Setup an ASyncReader, by giving the address of the read buffer,
58 * and the number of bytes we want to read.
59 *
60 * This also calls loopIo_wantRead(io) for you.
61 */
62 void asyncReader_init(AsyncReader* ar,
63 void* buffer,
64 size_t buffsize,
65 LoopIo* io);
66
67 /* Try to read data from 'io' and return the state of the read operation.
68 *
69 * Returns:
70 * ASYNC_COMPLETE: If the read operation was complete. This will also
71 * call loopIo_dontWantRead(io) for you.
72 *
73 * ASYNC_ERROR: If an error occured (see errno). The error will be
74 * ECONNRESET in case of disconnection.
75 *
76 * ASYNC_NEED_MORE: If there was not enough incoming data to complete
77 * the read (or if 'events' doesn't contain LOOP_IO_READ).
78 */
79 AsyncStatus asyncReader_read(AsyncReader* ar);
80
81 /**************************************************************************
82 **************************************************************************
83 *****
84 ***** A S Y N C W R I T E R
85 *****
86 *****/
87
88 /* An AsyncWriter is the counterpart of an AsyncReader, but for writing
89 * data to a file descriptor asynchronously.
90 */
91 typedef struct {
92 const uint8_t* buffer;
93 size_t buffsize;
94 size_t pos;
95 LoopIo* io;
96 } AsyncWriter;
97
98 /* Setup an ASyncWriter, by giving the address of the write buffer,
99 * and the number of bytes we want to write.
100 *
101 * This also calls loopIo_wantWrite(io) for you.
102 */
103 void asyncWriter_init(AsyncWriter* aw,
104 const void* buffer,
105 size_t buffsize,
106 LoopIo* io);
107
108 /* Try to write data to 'io' and return the state of the write operation.
109 *
110 * Returns:
111 * ASYNC_COMPLETE: If the write operation was complete. This will also
112 * call loopIo_dontWantWrite(io) for you.
113 *
114 * ASYNC_ERROR: If an error occured (see errno). The error will be
115 * ECONNRESET in case of disconnection.
116 *
117 * ASYNC_NEED_MORE: If not all bytes could be sent yet (or if 'events'
118 * doesn't contain LOOP_IO_WRITE).
119 */
120 AsyncStatus asyncWriter_write(AsyncWriter* aw);
121
122
123 /**************************************************************************
124 **************************************************************************
125 *****
126 ***** A S Y N C L I N E R E A D E R
127 *****
128 *****/
129
130 /* An AsyncLineReader allows you to read one line of text asynchronously.
131 * The biggest difference with AsyncReader is that you don't know the line
132 * size in advance, so the object will read data byte-by-byte until it
133 * encounters a '\n'.
134 */
135 typedef struct {
136 uint8_t* buffer;
137 size_t buffsize;
138 size_t pos;
139 LoopIo* io;
140 char eol;
141 } AsyncLineReader;
142
143 /* Setup an AsyncLineReader to read at most 'buffsize' characters (bytes)
144 * into 'buffer'. The reader will stop when it finds a '\n' which will be
145 * part of the buffer by default.
146 *
147 * NOTE: buffsize must be > 0. If not, asyncLineReader_getLine will return
148 * ASYNC_ERROR with errno == ENOMEM.
149 *
150 * buffsize must also sufficiently big to hold the final '\n'.
151 *
152 * Also calls loopIo_wantRead(io) for you.
153 */
154 void asyncLineReader_init(AsyncLineReader* alr,
155 void* buffer,
156 size_t buffsize,
157 LoopIo* io);
158
159 /* Sets line terminator character for the reader.
160 * By default, asyncLineReader_init will set EOL to be '\n'. Sometimes it's more
161 * convenient to have '\0' as line terminator, so "line" reader easily becomes
162 * a "string" reader.
163 */
164 AINLINED void
asyncLineReader_setEOL(AsyncLineReader * alr,char eol)165 asyncLineReader_setEOL(AsyncLineReader* alr, char eol)
166 {
167 alr->eol = eol;
168 }
169
170 /* Try to read line characters from 'io'.
171 * Returns:
172 * ASYNC_COMPLETE: An end-of-line was detected, call asyncLineReader_getLine
173 * to extract the line content.
174 *
175 * ASYNC_ERROR: An error occured. Note that in case of disconnection,
176 * errno will be set to ECONNRESET, but you should be able
177 * to call asyncLineReader_getLine to read the partial line
178 * that was read.
179 *
180 * In case of overflow, errno will be set to ENOMEM.
181 *
182 * ASYNC_NEED_MORE: If there was not enough incoming data (or events
183 * does not contain LOOP_IO_READ).
184 */
185 AsyncStatus asyncLineReader_read(AsyncLineReader* alr);
186
187 /* Return a pointer to the NON-ZERO-TERMINATED line characters, if any.
188 * If 'pLength" is not NULL, the function sets '*pLength' to the length
189 * in bytes of the line.
190 *
191 * Returns:
192 * NULL if 'buffsize' was initially 0, otherwise, a pointer to 'buffer'
193 * as passed in asyncLineReader_setup().
194 *
195 * NOTE: The data is *not* zero terminated, but its last character
196 * should be '\n' unless an error occured.
197 */
198 const char* asyncLineReader_getLineRaw(AsyncLineReader* alr, int *pLength);
199
200 /* Return a pointer to the ZERO-TERMINATED line, with final '\n' or '\r\n'
201 * stripped. This will be NULL in case of error though.
202 */
203 const char* asyncLineReader_getLine(AsyncLineReader* alr);
204
205 /**************************************************************************
206 **************************************************************************
207 *****
208 ***** A S Y N C C O N N E C T O R
209 *****
210 *****/
211
212 /* Asynchronous connection to a socket
213 */
214 typedef struct {
215 int error;
216 int state;
217 LoopIo* io;
218 } AsyncConnector;
219
220 AsyncStatus
221 asyncConnector_init(AsyncConnector* ac,
222 const SockAddress* address,
223 LoopIo* io);
224
225 AsyncStatus
226 asyncConnector_run(AsyncConnector* ac);
227
228 /* Stops connection in progress.
229 * Return:
230 * 0 if connection in progress has been stopped, or -1 if no connection has been
231 * in progress.
232 */
233 int
234 asyncConnector_stop(AsyncConnector* ac);
235
236 #endif /* ANDROID_ASYNC_UTILS_H */
237