adding MHD_run_from_select to API

5 files changed, 146 insertions, 32 deletions

diff --git a/ChangeLog b/ChangeLog
index 12edcf68..474c398a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Mar 31 20:27:48 CEST 2013
+        Adding new API call 'MHD_run_from_select' to allow programs
+        running in 'external select mode' to reduce the number of
+        'select' calls by a factor of two. -CG
+
 Sun Mar 31 20:03:48 CEST 2013
         Performance improvements, updated documentation.
         Make better use of available memory pool memory for
diff --git a/doc/libmicrohttpd.texi b/doc/libmicrohttpd.texi
index b5284c3c..d82ebeb3 100644
--- a/doc/libmicrohttpd.texi
+++ b/doc/libmicrohttpd.texi
@@ -1095,11 +1095,53 @@ Shutdown an HTTP daemon.
 Run webserver operations (without blocking unless in client callbacks).
 This method should be called by clients in combination with
 @code{MHD_get_fdset()} if the client-controlled @code{select}-method is used.
+@cindex select
+@cindex poll
+
+This function will work for external @code{poll} and @code{select} mode.
+However, if using external @code{select} mode, you may want to
+instead use @code{MHD_run_from_select}, as it is more efficient.
+
+@table @var
+@item daemon 
+daemon to process connections of
+@end table
 
 Return @code{MHD_YES} on success, @code{MHD_NO} if this daemon was not
 started with the right options for this call.
 @end deftypefun
 
+@deftypefun int MHD_run_from_select (struct MHD_Daemon *daemon, const fd_set *read_fd_set, const fd_set *write_fd_set, const fd_set *except_fd_set)
+Run webserver operations given sets of ready socket handles.
+@cindex select
+
+This method should be called by clients in combination with 
+@code{MHD_get_fdset} if the client-controlled (external)
+select method is used.
+
+You can use this function instead of @code{MHD_run} if you called
+@code{select} on the result from @code{MHD_get_fdset}.  File descriptors in
+the sets that are not controlled by MHD will be ignored.  Calling
+this function instead of @code{MHD_run} is more efficient as MHD will
+not have to call @code{select} again to determine which operations are
+ready.
+
+@table @var
+@item daemon 
+daemon to process connections of
+@item read_fd_set
+set of descriptors that must be ready for reading without blocking
+@item write_fd_set
+set of descriptors that must be ready for writing without blocking
+@item except_fd_set
+ignored, can be NULL
+@end table
+
+Return @code{MHD_YES} on success, @code{MHD_NO} on serious internal
+errors.
+
+@end deftypefun
+
 
 @deftypefun void MHD_add_connection (struct MHD_Daemon *daemon, int client_socket, const struct sockaddr *addr, socklen_t addrlen)
 Add another client connection to the set of connections 
diff --git a/src/daemon/EXPORT.sym b/src/daemon/EXPORT.sym
index 01418626..5c499b0b 100644
--- a/src/daemon/EXPORT.sym
+++ b/src/daemon/EXPORT.sym
@@ -4,6 +4,7 @@ MHD_stop_daemon
 MHD_get_fdset
 MHD_get_timeout
 MHD_run
+MHD_run_from_select
 MHD_get_connection_values
 MHD_set_connection_value
 MHD_lookup_connection_value
diff --git a/src/daemon/daemon.c b/src/daemon/daemon.c
index 72619c3d..bdd9f87b 100644
--- a/src/daemon/daemon.c
+++ b/src/daemon/daemon.c
@@ -1329,7 +1329,66 @@ MHD_get_timeout (struct MHD_Daemon *daemon,
 
 
 /**
- * Main select call.
+ * Run webserver operations. This method should be called by clients
+ * in combination with MHD_get_fdset if the client-controlled select
+ * method is used.
+ *
+ * You can use this function instead of "MHD_run" if you called
+ * 'select' on the result from "MHD_get_fdset".  File descriptors in
+ * the sets that are not controlled by MHD will be ignored.  Calling
+ * this function instead of "MHD_run" is more efficient as MHD will
+ * not have to call 'select' again to determine which operations are
+ * ready.
+ *
+ * @param daemon daemon to run select loop for
+ * @param read_fd_set read set
+ * @param write_fd_set write set
+ * @param except_fd_set except set (not used, can be NULL)
+ * @return MHD_NO on serious errors, MHD_YES on success
+ */
+int
+MHD_run_from_select (struct MHD_Daemon *daemon, 
+                     const fd_set *read_fd_set,
+                     const fd_set *write_fd_set,
+                     const fd_set *except_fd_set)
+{
+  int ds;
+  struct MHD_Connection *pos;
+  struct MHD_Connection *next;
+
+  /* select connection thread handling type */
+  if ( (-1 != (ds = daemon->socket_fd)) &&
+       (FD_ISSET (ds, read_fd_set)) )
+    MHD_accept_connection (daemon);
+  if (0 == (daemon->options & MHD_USE_THREAD_PER_CONNECTION))
+    {
+      /* do not have a thread per connection, process all connections now */
+      next = daemon->connections_head;
+      while (NULL != (pos = next))
+        {
+          next = pos->next;
+          ds = pos->socket_fd;
+          if (ds != -1)
+            {
+              if ( (FD_ISSET (ds, read_fd_set))
+#if HTTPS_SUPPORT
+                   || (MHD_YES == pos->tls_read_ready) 
+#endif
+                   )
+                pos->read_handler (pos);
+              if (FD_ISSET (ds, write_fd_set))
+                pos->write_handler (pos);
+              pos->idle_handler (pos);
+            }
+        }
+    }
+  return MHD_YES;
+}
+
+
+/**
+ * Main internal select call.  Will compute select sets, call 'select'
+ * and then MHD_run_from_select with the result.
  *
  * @param daemon daemon to run select loop for
  * @param may_block YES if blocking, NO if non-blocking
@@ -1339,8 +1398,6 @@ static int
 MHD_select (struct MHD_Daemon *daemon, 
             int may_block)
 {
-  struct MHD_Connection *pos;
-  struct MHD_Connection *next;
   int num_ready;
   fd_set rs;
   fd_set ws;
@@ -1349,7 +1406,6 @@ MHD_select (struct MHD_Daemon *daemon,
   struct timeval timeout;
   struct timeval *tv;
   MHD_UNSIGNED_LONG_LONG ltimeout;
-  int ds;
 
   timeout.tv_sec = 0;
   timeout.tv_usec = 0;
@@ -1404,7 +1460,6 @@ MHD_select (struct MHD_Daemon *daemon,
       tv = &timeout;
     }
   num_ready = SELECT (max + 1, &rs, &ws, &es, tv);
-
   if (MHD_YES == daemon->shutdown)
     return MHD_NO;
   if (num_ready < 0)
@@ -1416,33 +1471,7 @@ MHD_select (struct MHD_Daemon *daemon,
 #endif
       return MHD_NO;
     }
-  /* select connection thread handling type */
-  if ( (-1 != (ds = daemon->socket_fd)) &&
-       (FD_ISSET (ds, &rs)) )
-    MHD_accept_connection (daemon);
-  if (0 == (daemon->options & MHD_USE_THREAD_PER_CONNECTION))
-    {
-      /* do not have a thread per connection, process all connections now */
-      next = daemon->connections_head;
-      while (NULL != (pos = next))
-        {
-          next = pos->next;
-          ds = pos->socket_fd;
-          if (ds != -1)
-            {
-              if ( (FD_ISSET (ds, &rs))
-#if HTTPS_SUPPORT
-                   || (MHD_YES == pos->tls_read_ready) 
-#endif
-                   )
-                pos->read_handler (pos);
-              if (FD_ISSET (ds, &ws))
-                pos->write_handler (pos);
-              pos->idle_handler (pos);
-            }
-        }
-    }
-  return MHD_YES;
+  return MHD_run_from_select (daemon, &rs, &ws, &es);
 }
 
 
@@ -1647,6 +1676,10 @@ MHD_poll (struct MHD_Daemon *daemon,
  * by clients in combination with MHD_get_fdset
  * if the client-controlled select method is used.
  *
+ * This function will work for external 'poll' and 'select' mode.
+ * However, if using external 'select' mode, you may want to
+ * instead use 'MHD_run_from_select', as it is more efficient.
+ *
  * @return MHD_YES on success, MHD_NO if this
  *         daemon was not started with the right
  *         options for this call.
diff --git a/src/include/microhttpd.h b/src/include/microhttpd.h
index 3d406c2e..4da26191 100644
--- a/src/include/microhttpd.h
+++ b/src/include/microhttpd.h
@@ -1182,6 +1182,14 @@ int MHD_get_timeout (struct MHD_Daemon *daemon,
  * by clients in combination with MHD_get_fdset
  * if the client-controlled select method is used.
  *
+ * This function is a convenience method, which is useful if the
+ * fd_sets from "MHD_get_fdset" were not directly passed to 'select';
+ * with this function, MHD will internally do the appropriate 'select'
+ * call itself again.  While it is always safe to call 'MHD_run' (in
+ * external select mode), you should call 'MHD_run_from_select' if
+ * performance is important (as it saves an expensive call to
+ * 'select').
+ *
  * @param daemon daemon to run
  * @return MHD_YES on success, MHD_NO if this
  *         daemon was not started with the right
@@ -1191,6 +1199,31 @@ int
 MHD_run (struct MHD_Daemon *daemon);
 
 
+/**
+ * Run webserver operations. This method should be called by clients
+ * in combination with MHD_get_fdset if the client-controlled select
+ * method is used.
+ *
+ * You can use this function instead of "MHD_run" if you called
+ * 'select' on the result from "MHD_get_fdset".  File descriptors in
+ * the sets that are not controlled by MHD will be ignored.  Calling
+ * this function instead of "MHD_run" is more efficient as MHD will
+ * not have to call 'select' again to determine which operations are
+ * ready.
+ *
+ * @param daemon daemon to run select loop for
+ * @param read_fd_set read set
+ * @param write_fd_set write set
+ * @param except_fd_set except set (not used, can be NULL)
+ * @return MHD_NO on serious errors, MHD_YES on success
+ */
+int
+MHD_run_from_select (struct MHD_Daemon *daemon, 
+                     const fd_set *read_fd_set,
+                     const fd_set *write_fd_set,
+                     const fd_set *except_fd_set);
+
+
 /* **************** Connection handling functions ***************** */
 
 /**