hoist out handle_nonblock function for xread and xwrite

At least for me, this improves the readability of xread and xwrite; hopefully allowing missing "continue" statements to be spotted more easily. Signed-off-by: Eric Wong <e@80x24.org> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Eric Wong committed Jul 10, 2016 at 08:20 UTC d751dd11ae16fd4e2410d3a32c8e2d951fafc923
1 file changed +20 -28
wrapper.c
+20 -28
@@ -224,6 +224,24 @@ int xopen(const char *path, int oflag, ...)
224 }
225 }
226
227 +static int handle_nonblock(int fd, short poll_events, int err)
228 +{
229 + struct pollfd pfd;
230 +
231 + if (err != EAGAIN && err != EWOULDBLOCK)
232 + return 0;
233 +
234 + pfd.fd = fd;
235 + pfd.events = poll_events;
236 +
237 + /*
238 + * no need to check for errors, here;
239 + * a subsequent read/write will detect unrecoverable errors
240 + */
241 + poll(&pfd, 1, -1);
242 + return 1;
243 +}
244 +
245 /*
246 * xread() is the same a read(), but it automatically restarts read()
247 * operations with a recoverable error (EAGAIN and EINTR). xread()
@@ -239,21 +257,8 @@ ssize_t xread(int fd, void *buf, size_t len)
257 if (nr < 0) {
258 if (errno == EINTR)
259 continue;
242 - if (errno == EAGAIN || errno == EWOULDBLOCK) {
243 - struct pollfd pfd;
244 - pfd.events = POLLIN;
245 - pfd.fd = fd;
246 - /*
247 - * it is OK if this poll() failed; we
248 - * want to leave this infinite loop
249 - * only when read() returns with
250 - * success, or an expected failure,
251 - * which would be checked by the next
252 - * call to read(2).
253 - */
254 - poll(&pfd, 1, -1);
260 + if (handle_nonblock(fd, POLLIN, errno))
261 continue;
256 - }
262 }
263 return nr;
264 }
@@ -274,21 +279,8 @@ ssize_t xwrite(int fd, const void *buf, size_t len)
279 if (nr < 0) {
280 if (errno == EINTR)
281 continue;
277 - if (errno == EAGAIN || errno == EWOULDBLOCK) {
278 - struct pollfd pfd;
279 - pfd.events = POLLOUT;
280 - pfd.fd = fd;
281 - /*
282 - * it is OK if this poll() failed; we
283 - * want to leave this infinite loop
284 - * only when write() returns with
285 - * success, or an expected failure,
286 - * which would be checked by the next
287 - * call to write(2).
288 - */
289 - poll(&pfd, 1, -1);
282 + if (handle_nonblock(fd, POLLOUT, errno))
283 continue;
291 - }
284 }
285
286 return nr;