D(("disabling mode %s fd %d", modenames[mode], fd));
FD_CLR(fd, &ev->mode[mode].enabled);
FD_CLR(fd, &ev->mode[mode].tripped);
+ /* Suppress any pending callbacks */
+ ev->escape = 1;
return 0;
}
(void *)b->base, (void *)b->start, (void *)b->end, (void *)b->top));
}
-/* buffered writer ************************************************************/
+/* readers and writers *******************************************************/
/** @brief State structure for a buffered writer */
struct ev_writer {
+ /** @brief Sink used for writing to the buffer */
struct sink s;
+
+ /** @brief Output buffer */
struct buffer b;
+
+ /** @brief File descriptor to write to */
int fd;
+
+ /** @brief Set if there'll be no more output */
int eof;
+
+ /** @brief Error/termination callback */
ev_error_callback *callback;
+
+ /** @brief Passed to @p callback */
void *u;
+
+ /** @brief Parent event source */
ev_source *ev;
/** @brief Maximum amount of time between succesful writes, 0 = don't care */
int timebound;
/** @brief Maximum amount of data to buffer, 0 = don't care */
int spacebound;
- /** @brief Synthesized error code */
- int syntherror;
+ /** @brief Error code to pass to @p callback (see writer_shutdown()) */
+ int error;
/** @brief Timeout handle for @p timebound (or 0) */
ev_timeout_handle timeout;
+ /** @brief Description of this writer */
const char *what;
+
+ /** @brief Tied reader or 0 */
+ ev_reader *reader;
};
-/** @brief Synthesized error callback
+/** @brief State structure for a buffered reader */
+struct ev_reader {
+ /** @brief Input buffer */
+ struct buffer b;
+ /** @brief File descriptor read from */
+ int fd;
+ /** @brief Called when new data is available */
+ ev_reader_callback *callback;
+ /** @brief Called on error and shutdown */
+ ev_error_callback *error_callback;
+ /** @brief Passed to @p callback and @p error_callback */
+ void *u;
+ /** @brief Parent event loop */
+ ev_source *ev;
+ /** @brief Set when EOF is detected */
+ int eof;
+ /** @brief Error code to pass to error callback */
+ int error;
+ /** @brief Tied writer or NULL */
+ ev_writer *writer;
+};
+
+/* buffered writer ************************************************************/
+
+/** @brief Shut down the writer
+ *
+ * This is called to shut down a writer. The error callback is not called
+ * through any other path. Also we do not cancel @p fd from anywhere else,
+ * though we might disable it.
+ *
+ * It has the signature of a timeout callback so that it can be called from a
+ * time=0 timeout.
*
* Calls @p callback with @p w->syntherr as the error code (which might be 0).
*/
const attribute((unused)) struct timeval *now,
void *u) {
ev_writer *w = u;
- int fd;
if(w->fd == -1)
- return 0; /* already closed */
+ return 0; /* already shut down */
+ info("writer_shutdown fd=%d", w->fd);
ev_timeout_cancel(ev, w->timeout);
+ ev_fd_cancel(ev, ev_write, w->fd);
w->timeout = 0;
- fd = w->fd;
+ if(w->reader) {
+ /* If there is a reader still around we just untie it */
+ w->reader->writer = 0;
+ shutdown(w->fd, SHUT_WR); /* there'll be no more writes */
+ } else {
+ /* There's no reader so we are free to close the FD */
+ xclose(w->fd);
+ }
w->fd = -1;
- return w->callback(ev, fd, w->syntherror, w->u);
+ return w->callback(ev, w->error, w->u);
}
/** @brief Called when a writer's @p timebound expires */
static int writer_timebound_exceeded(ev_source *ev,
- const struct timeval attribute((unused)) *now,
+ const struct timeval *now,
void *u) {
ev_writer *const w = u;
- int fd;
- if(w->fd == -1)
- return 0; /* already closed */
error(0, "abandoning writer %s because no writes within %ds",
w->what, w->timebound);
- fd = w->fd;
- w->fd = -1;
- return w->callback(ev, fd, ETIMEDOUT, w->u);
+ w->error = ETIMEDOUT;
+ return writer_shutdown(ev, now, u);
}
/** @brief Set the time bound callback (if not set already) */
ev_writer *const w = u;
int n;
- if(w->fd == -1)
- return 0;
n = write(fd, w->b.start, w->b.end - w->b.start);
D(("callback for writer fd %d, %ld bytes, n=%d, errno=%d",
fd, (long)(w->b.end - w->b.start), n, errno));
if(n >= 0) {
+ /* Consume bytes from the buffer */
w->b.start += n;
+ /* Suppress any outstanding timeout */
ev_timeout_cancel(ev, w->timeout);
w->timeout = 0;
if(w->b.start == w->b.end) {
+ /* The buffer is empty */
if(w->eof) {
- ev_fd_cancel(ev, ev_write, fd);
- w->fd = -1;
- return w->callback(ev, fd, 0, w->u);
+ /* We're done, we can shut down this writer */
+ w->error = 0;
+ return writer_shutdown(ev, 0, w);
} else
+ /* There might be more to come but we don't need writer_callback() to
+ * be called for the time being */
ev_fd_disable(ev, ev_write, fd);
} else
+ /* The buffer isn't empty, set a timeout so we give up if we don't manage
+ * to write some more within a reasonable time */
writer_set_timebound(w);
} else {
switch(errno) {
case EAGAIN:
break;
default:
- ev_fd_cancel(ev, ev_write, fd);
- w->fd = -1;
- return w->callback(ev, fd, errno, w->u);
+ w->error = errno;
+ return writer_shutdown(ev, 0, w);
}
}
return 0;
if(!n)
return 0; /* avoid silliness */
- buffer_space(&w->b, n);
- if(w->b.start == w->b.end)
- ev_fd_enable(w->ev, ev_write, w->fd);
- memcpy(w->b.end, s, n);
- w->b.end += n;
- if(w->spacebound && w->b.end - w->b.start > w->spacebound) {
- /* Buffer contents have exceeded the space bound. We assume that the
+ if(w->spacebound && w->b.end - w->b.start + n > w->spacebound) {
+ /* The new buffer contents will exceed the space bound. We assume that the
* remote client has gone away and TCP hasn't noticed yet, or that it's got
* hopelessly stuck. */
error(0, "abandoning writer %s because buffer has reached %td bytes",
w->what, w->b.end - w->b.start);
- w->syntherror = EPIPE;
- ev_fd_cancel(w->ev, ev_write, w->fd);
+ ev_fd_disable(w->ev, ev_write, w->fd);
+ w->error = EPIPE;
return ev_timeout(w->ev, 0, 0, writer_shutdown, w);
}
+ /* Make sure there is space */
+ buffer_space(&w->b, n);
+ /* If the buffer was formerly empty then we'll need to re-enable the FD */
+ if(w->b.start == w->b.end)
+ ev_fd_enable(w->ev, ev_write, w->fd);
+ memcpy(w->b.end, s, n);
+ w->b.end += n;
+ /* Arrange a timeout if there wasn't one set already */
writer_set_timebound(w);
return 0;
}
* @param u Passed to @p callback
* @param what Text description
* @return New writer or @c NULL
+ *
+ * Writers own their file descriptor and close it when they have finished with
+ * it.
+ *
+ * If you pass the same fd to a reader and writer, you must tie them together
+ * with ev_tie().
*/
ev_writer *ev_writer_new(ev_source *ev,
int fd,
w->what = what;
if(ev_fd(ev, ev_write, fd, writer_callback, w, what))
return 0;
+ /* Buffer is initially empty so we don't want a callback */
ev_fd_disable(ev, ev_write, fd);
return w;
}
*/
int ev_writer_close(ev_writer *w) {
D(("close writer fd %d", w->fd));
+ if(w->eof)
+ return 0; /* already closed */
w->eof = 1;
if(w->b.start == w->b.end) {
- /* we're already finished */
- w->syntherror = 0; /* no error */
- ev_fd_cancel(w->ev, ev_write, w->fd);
+ /* We're already finished */
+ w->error = 0; /* no error */
return ev_timeout(w->ev, 0, 0, writer_shutdown, w);
}
return 0;
}
-/** @brief Cancel a writer discarding any buffered data
- * @param w Writer to close
- * @return 0 on success, non-0 on error
- *
- * This cancels a writer immediately. Any unwritten buffered data is discarded
- * and the error callback is never called. This is appropriate to call if (for
- * instance) the read half of a TCP connection is known to have failed and the
- * writer is therefore obsolete.
- */
-int ev_writer_cancel(ev_writer *w) {
- ev_source *const ev = w->ev;
- D(("cancel writer fd %d", w->fd));
- ev_timeout_cancel(ev, w->timeout);
- w->timeout = 0;
- return ev_fd_cancel(w->ev, ev_write, w->fd);
-}
-
/** @brief Attempt to flush a writer
* @param w Writer to flush
* @return 0 on success, non-0 on error
/* buffered reader ************************************************************/
-/** @brief State structure for a buffered reader */
-struct ev_reader {
- struct buffer b;
- int fd;
- ev_reader_callback *callback;
- ev_error_callback *error_callback;
- void *u;
- ev_source *ev;
- int eof;
-};
+/** @brief Shut down a reader*
+ *
+ * This is the only path through which we cancel and close the file descriptor.
+ * As with the writer case it is given timeout signature to allow it be
+ * deferred to the next iteration of the event loop.
+ *
+ * We only call @p error_callback if @p error is nonzero (unlike the writer
+ * case).
+ */
+static int reader_shutdown(ev_source *ev,
+ const attribute((unused)) struct timeval *now,
+ void *u) {
+ ev_reader *const r = u;
+
+ if(r->fd == -1)
+ return 0; /* already shut down */
+ info("reader_shutdown fd=%d", r->fd);
+ ev_fd_cancel(ev, ev_read, r->fd);
+ r->eof = 1;
+ if(r->writer) {
+ /* If there is a writer still around we just untie it */
+ r->writer->reader = 0;
+ shutdown(r->fd, SHUT_RD); /* there'll be no more reads */
+ } else {
+ /* There's no writer so we are free to close the FD */
+ xclose(r->fd);
+ }
+ r->fd = -1;
+ if(r->error)
+ return r->error_callback(ev, r->error, r->u);
+ else
+ return 0;
+}
/** @brief Called when a reader's @p fd is readable */
static int reader_callback(ev_source *ev, int fd, void *u) {
fd, (int)(r->b.top - r->b.end), n, errno));
if(n > 0) {
r->b.end += n;
- return r->callback(ev, r, fd, r->b.start, r->b.end - r->b.start, 0, r->u);
+ return r->callback(ev, r, r->b.start, r->b.end - r->b.start, 0, r->u);
} else if(n == 0) {
- r->eof = 1;
- ev_fd_cancel(ev, ev_read, fd);
- return r->callback(ev, r, fd, r->b.start, r->b.end - r->b.start, 1, r->u);
+ /* No more read callbacks needed */
+ ev_fd_disable(r->ev, ev_read, r->fd);
+ ev_timeout(r->ev, 0, 0, reader_shutdown, r);
+ /* Pass the remaining data and an eof indicator to the user */
+ return r->callback(ev, r, r->b.start, r->b.end - r->b.start, 1, r->u);
} else {
switch(errno) {
case EINTR:
case EAGAIN:
break;
default:
- ev_fd_cancel(ev, ev_read, fd);
- return r->error_callback(ev, fd, errno, r->u);
+ /* Fatal error, kill the reader now */
+ r->error = errno;
+ return reader_shutdown(ev, 0, r);
}
}
return 0;
* @param u Passed to callbacks
* @param what Text description
* @return New reader or @c NULL
+ *
+ * Readers own their fd and close it when they are finished with it.
+ *
+ * If you pass the same fd to a reader and writer, you must tie them together
+ * with ev_tie().
*/
ev_reader *ev_reader_new(ev_source *ev,
int fd,
/** @brief Cancel a reader
* @param r Reader
* @return 0 on success, non-0 on error
+ *
+ * No further callbacks will be made, and the FD will be closed (in a later
+ * iteration of the event loop).
*/
int ev_reader_cancel(ev_reader *r) {
D(("cancel reader fd %d", r->fd));
- return ev_fd_cancel(r->ev, ev_read, r->fd);
+ if(r->fd == -1)
+ return 0; /* already thoroughly cancelled */
+ ev_fd_disable(r->ev, ev_read, r->fd);
+ return ev_timeout(r->ev, 0, 0, reader_shutdown, r);
}
/** @brief Temporarily disable a reader
*/
int ev_reader_disable(ev_reader *r) {
D(("disable reader fd %d", r->fd));
- return r->eof ? 0 : ev_fd_disable(r->ev, ev_read, r->fd);
+ return ev_fd_disable(r->ev, ev_read, r->fd);
}
/** @brief Called from ev_run() for ev_reader_incomplete() */
ev_reader *r = u;
D(("reader continuation callback fd %d", r->fd));
- if(ev_fd_enable(r->ev, ev_read, r->fd)) return -1;
- return r->callback(ev, r, r->fd, r->b.start, r->b.end - r->b.start, r->eof, r->u);
+ /* If not at EOF turn the FD back on */
+ if(!r->eof)
+ if(ev_fd_enable(r->ev, ev_read, r->fd))
+ return -1;
+ /* We're already in a timeout callback so there's no reason we can't call the
+ * user callback directly (compare ev_reader_enable()). */
+ return r->callback(ev, r, r->b.start, r->b.end - r->b.start, r->eof, r->u);
}
/** @brief Arrange another callback
ev_reader *r = u;
D(("reader enabled callback fd %d", r->fd));
- return r->callback(ev, r, r->fd, r->b.start, r->b.end - r->b.start, r->eof, r->u);
+ return r->callback(ev, r, r->b.start, r->b.end - r->b.start, r->eof, r->u);
}
/** @brief Re-enable reading
* re-enable. You'll automatically get another callback directly from the
* event loop (i.e. not from inside ev_reader_enable()) so you can handle the
* next line (or whatever) if the whole thing has in fact already arrived.
+ *
+ * The difference between this process and calling ev_reader_incomplete() is
+ * ev_reader_incomplete() deals with the case where you can process now but
+ * would rather yield to other clients of the event loop, while using
+ * ev_reader_disable() and ev_reader_enable() deals with the case where you
+ * cannot process input yet because some other process is actually not
+ * complete.
*/
int ev_reader_enable(ev_reader *r) {
D(("enable reader fd %d", r->fd));
- return ((r->eof ? 0 : ev_fd_enable(r->ev, ev_read, r->fd))
- || ev_timeout(r->ev, 0, 0, reader_enabled, r)) ? -1 : 0;
+
+ /* First if we're not at EOF then we re-enable reading */
+ if(!r->eof)
+ if(ev_fd_enable(r->ev, ev_read, r->fd))
+ return -1;
+ /* Arrange another callback next time round the event loop */
+ return ev_timeout(r->ev, 0, 0, reader_enabled, r);
+}
+
+/** @brief Tie a reader and a writer together
+ * @param r Reader
+ * @param w Writer
+ * @return 0 on success, non-0 on error
+ *
+ * This function must be called if @p r and @p w share a file descritptor.
+ */
+int ev_tie(ev_reader *r, ev_writer *w) {
+ assert(r->writer == 0);
+ assert(w->reader == 0);
+ r->writer = w;
+ w->reader = r;
+ return 0;
}
/*
~mdw / disorder / commitdiff