Implemented yaz_poll - select/poll wrapper.

[yaz-moved-to-github.git] / src / poll.c

diff --git a/src/poll.c b/src/poll.c
new file mode 100644 (file)
index 0000000..c877f0a
--- /dev/null
+++ b/src/poll.c
@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 1995-2007, Index Data ApS
+ * See the file LICENSE for details.
+ *
+ * $Id: poll.c,v 1.1 2007-11-09 16:46:43 adam Exp $
+ */
+/**
+ * \file 
+ * \brief Select, poll wrapper
+ */
+
+#include <assert.h>
+#include <string.h>
+#include <errno.h>
+
+#include <yaz/log.h>
+#include <yaz/xmalloc.h>
+#include <yaz/poll.h>
+
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#if HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+#if HAVE_SYS_POLL_H
+#include <sys/poll.h>
+#endif
+#if HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+#ifdef WIN32
+#if FD_SETSIZE < 512
+#define FD_SETSIZE 512
+#endif
+#include <winsock.h>
+#endif
+
+/*
+  Note that yaz_poll_select is limited as to how many file
+  descriptors it can multiplex due to its use of select() which in
+  turn uses the statically defined fd_set type to be a bitmap of the
+  file descriptors to check.  On Ubuntu 6.06 (and almost certainly on
+  Debian, and probably on all Linuxes, and maybe all Unixes) this is
+  by default set to 1024 (though it may be possible to override this
+  using a #define before including <sys/select.h> -- I've not tried
+  this).  1024 file descriptors is a lot, but not enough in all
+  cases, e.g. when running IRSpy on a large target database.  So you
+  should ensure that YAZ uses ZOOM_yaz_poll_poll() when possible.
+*/
+int yaz_poll_select(struct yaz_poll_fd *fds, int num_fds, int timeout)
+{
+    struct timeval tv;
+    fd_set input, output, except;
+    int i, r;
+    int max_fd = 0;
+
+    FD_ZERO(&input);
+    FD_ZERO(&output);
+    FD_ZERO(&except);
+
+    assert(num_fds > 0);
+    for (i = 0; i < num_fds; i++)
+    {
+        enum yaz_poll_mask mask = fds[i].input_mask;
+        int fd = fds[i].fd;
+
+        if (mask & yaz_poll_read)
+            FD_SET(fd, &input);
+        if (mask & yaz_poll_write)
+            FD_SET(fd, &output);
+        if (mask & yaz_poll_except)
+            FD_SET(fd, &except);
+        if (max_fd < fd)
+            max_fd = fd;
+    }
+    tv.tv_sec = timeout;
+    tv.tv_usec = 0;
+
+    while ((r = select(max_fd+1, &input, &output, &except,
+                       (timeout == -1 ? 0 : &tv))) < 0 && errno == EINTR)
+    {
+        ;
+    }
+    for (i = 0; i < num_fds; i++)
+    {
+        enum yaz_poll_mask mask = 0;
+        int fd = fds[i].fd;
+        if (!r)
+            mask += yaz_poll_timeout;
+        else
+        {
+            if (FD_ISSET(fd, &input))
+                mask += yaz_poll_read;
+            if (FD_ISSET(fd, &output))
+                mask += yaz_poll_write;
+            if (FD_ISSET(fd, &except))
+                mask += yaz_poll_except;
+        }
+        fds[i].output_mask = mask;
+    }
+    return r;
+}
+
+#if HAVE_SYS_POLL_H
+int yaz_poll_poll(struct yaz_poll_fd *fds, int num_fds, int timeout)
+{
+    int r;
+    struct pollfd *pollfds = (struct pollfd *) 
+        xmalloc(num_fds * sizeof *pollfds);
+    int i;
+
+    assert(num_fds > 0);
+    for (i = 0; i < num_fds; i++)
+    {
+        enum yaz_poll_mask mask = fds[i].input_mask;
+        int fd = fds[i].fd;
+        short poll_events = 0;
+
+        if (mask & yaz_poll_read)
+            poll_events += POLLIN;
+        if (mask & yaz_poll_write)
+            poll_events += POLLOUT;
+        if (mask & yaz_poll_except)
+            poll_events += POLLERR;
+        pollfds[i].fd = fd;
+        pollfds[i].events = poll_events;
+        pollfds[i].revents = 0;
+    }
+    while ((r = poll(pollfds, num_fds,
+                     (timeout == -1 ? -1 : timeout * 1000))) < 0
+           && errno == EINTR)
+    {
+        ;
+    }
+    if (r >= 0)
+    {
+        for (i = 0; i < num_fds; i++)
+        {
+            enum yaz_poll_mask mask = 0;
+            if (!r)
+                mask += yaz_poll_timeout;
+            else
+            {
+                if (pollfds[i].revents & POLLIN)
+                    mask += yaz_poll_read;
+                if (pollfds[i].revents & POLLOUT)
+                    mask += yaz_poll_write;
+                if (pollfds[i].revents & POLLERR)
+                    mask += yaz_poll_except;
+            }
+            fds[i].output_mask = mask;
+        }
+    }
+    xfree(pollfds);
+    return r;
+}
+#endif
+
+int yaz_poll(struct yaz_poll_fd *fds, int num_fds, int timeout)
+{
+#if YAZ_HAVE_SYS_POLL_H
+    return yaz_poll_poll(fds, num_fds, timeout);
+#else
+    return yaz_poll_select(fds, num_fds, timeout);
+#endif
+}
+
+/*
+ * Local variables:
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ * vim: shiftwidth=4 tabstop=8 expandtab
+ */
+