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>

diff --git a/wrapper.c b/wrapper.c
index f7ea6c43bee7b5483ed82d273832e7ac6ea32e24..a774ab7d80737d0caa6a753fa51c220816e817be 100644 (file)
--- a/wrapper.c
+++ b/wrapper.c
@@ -224,6 +224,24 @@ int xopen(const char *path, int oflag, ...)
        }
 }
 
+static int handle_nonblock(int fd, short poll_events, int err)
+{
+       struct pollfd pfd;
+
+       if (err != EAGAIN && err != EWOULDBLOCK)
+               return 0;
+
+       pfd.fd = fd;
+       pfd.events = poll_events;
+
+       /*
+        * no need to check for errors, here;
+        * a subsequent read/write will detect unrecoverable errors
+        */
+       poll(&pfd, 1, -1);
+       return 1;
+}
+
 /*
  * xread() is the same a read(), but it automatically restarts read()
  * operations with a recoverable error (EAGAIN and EINTR). xread()
@@ -239,21 +257,8 @@ ssize_t xread(int fd, void *buf, size_t len)
                if (nr < 0) {
                        if (errno == EINTR)
                                continue;
-                       if (errno == EAGAIN || errno == EWOULDBLOCK) {
-                               struct pollfd pfd;
-                               pfd.events = POLLIN;
-                               pfd.fd = fd;
-                               /*
-                                * it is OK if this poll() failed; we
-                                * want to leave this infinite loop
-                                * only when read() returns with
-                                * success, or an expected failure,
-                                * which would be checked by the next
-                                * call to read(2).
-                                */
-                               poll(&pfd, 1, -1);
+                       if (handle_nonblock(fd, POLLIN, errno))
                                continue;
-                       }
                }
                return nr;
        }
@@ -274,21 +279,8 @@ ssize_t xwrite(int fd, const void *buf, size_t len)
                if (nr < 0) {
                        if (errno == EINTR)
                                continue;
-                       if (errno == EAGAIN || errno == EWOULDBLOCK) {
-                               struct pollfd pfd;
-                               pfd.events = POLLOUT;
-                               pfd.fd = fd;
-                               /*
-                                * it is OK if this poll() failed; we
-                                * want to leave this infinite loop
-                                * only when write() returns with
-                                * success, or an expected failure,
-                                * which would be checked by the next
-                                * call to write(2).
-                                */
-                               poll(&pfd, 1, -1);
+                       if (handle_nonblock(fd, POLLOUT, errno))
                                continue;
-                       }
                }
 
                return nr;