Switch io_close(), io_input() from timeouts to deadlines

[empserver] / src / lib / empthread / io.c

diff --git a/src/lib/empthread/io.c b/src/lib/empthread/io.c
index 0e65c86ed972da2c0d49d72fcbd58bcc54818eb4..9b7955b50b72235009e37f37f69db5e36e6d184b 100644 (file)
--- a/src/lib/empthread/io.c
+++ b/src/lib/empthread/io.c
@@ -63,16 +63,17 @@ struct iop {
     int flags;
     int bufsize;
     int last_out;
-    struct timeval input_timeout;
 };
 
+static struct timeval *io_timeout(struct timeval *, time_t);
+
 void
 io_init(void)
 {
 }
 
 struct iop *
-io_open(int fd, int flags, int bufsize, struct timeval timeout)
+io_open(int fd, int flags, int bufsize)
 {
     int fdfl;
     struct iop *iop;
@@ -97,7 +98,6 @@ io_open(int fd, int flags, int bufsize, struct timeval timeout)
     iop->flags = flags;
     iop->last_out = 0;
     iop->bufsize = bufsize;
-    iop->input_timeout = timeout;
     if (flags & IO_READ)
        iop->input = ioq_create(bufsize);
     if (flags & IO_WRITE)
@@ -106,14 +106,16 @@ io_open(int fd, int flags, int bufsize, struct timeval timeout)
 }
 
 void
-io_close(struct iop *iop)
+io_close(struct iop *iop, time_t deadline)
 {
+    struct timeval timeout;
     char buf[IO_BUFSIZE];
     int ret;
 
     while (io_output(iop, 1) > 0) ;
     shutdown(iop->fd, SHUT_WR);
-    while (empth_select(iop->fd, EMPTH_FD_READ, &iop->input_timeout) > 0) {
+    while (empth_select(iop->fd, EMPTH_FD_READ,
+                       io_timeout(&timeout, deadline)) > 0) {
        ret = read(iop->fd, buf, sizeof(buf));
        if (ret <= 0)
            break;
@@ -126,15 +128,43 @@ io_close(struct iop *iop)
     free(iop);
 }
 
+static struct timeval *
+io_timeout(struct timeval *timeout, time_t deadline)
+{
+    struct timeval now;
+
+    if (deadline == (time_t)-1)
+       return NULL;            /* no deadline */
+
+    gettimeofday(&now, NULL);
+    if (now.tv_sec >= deadline) {
+       /* deadline reached already */
+       timeout->tv_sec = 0;
+       timeout->tv_usec = 0;
+    } else {
+       /* deadline in future */
+       timeout->tv_sec = deadline - now.tv_sec - 1;
+       timeout->tv_usec = 999999 - now.tv_usec;
+       /* yes, this is 1usec early; sue me */
+    }
+
+    return timeout;
+}
+
 /*
- * Return number of bytes read on success, zero on timeout, early
- * wakeup or EOF, -1 on error.  In particular, return 0 when no data
- * is available for non-blocking input (WAITFORINPUT false).
- * Use io_eof() to distinguish timeout and early wakeup from EOF.
+ * Read input from IOP and enqueue it.
+ * Wait at most until DEADLINE for input to arrive.  (time_t)-1 means
+ * wait as long as it takes (no timeout).
+ * Does not yield the processor when DEADLINE is zero.
+ * A wait for input can be cut short by empth_wakeup().
+ * Return number of bytes read on success, -1 on error.
+ * In particular, return zero on timeout, early wakeup or EOF.  Use
+ * io_eof() to distinguish timeout and early wakeup from EOF.
  */
 int
-io_input(struct iop *iop, int waitforinput)
+io_input(struct iop *iop, time_t deadline)
 {
+    struct timeval timeout;
     char buf[IO_BUFSIZE];
     int cc;
     int res;
@@ -146,9 +176,9 @@ io_input(struct iop *iop, int waitforinput)
     if (iop->flags & IO_EOF)
        return 0;
 
-    /* Wait for the file to have input. */
-    if (waitforinput) {
-       res = empth_select(iop->fd, EMPTH_FD_READ, &iop->input_timeout);
+    if (deadline) {
+       res = empth_select(iop->fd, EMPTH_FD_READ,
+                          io_timeout(&timeout, deadline));
        if (res < 0) {
            iop->flags |= IO_ERROR;
            return -1;
@@ -156,7 +186,6 @@ io_input(struct iop *iop, int waitforinput)
            return 0;
     }
 
-    /* Do the actual read. */
     cc = read(iop->fd, buf, sizeof(buf));
     if (cc < 0) {
        if (errno == EAGAIN || errno == EWOULDBLOCK)
@@ -164,14 +193,11 @@ io_input(struct iop *iop, int waitforinput)
        iop->flags |= IO_ERROR;
        return -1;
     }
-
-    /* We eof'd */
     if (cc == 0) {
        iop->flags |= IO_EOF;
        return 0;
     }
 
-    /* Append the input to the IOQ. */
     ioq_append(iop->input, buf, cc);
     return cc;
 }