add io_fd_flags so the caller can tell io_fd whether the socket is blocking

(saves one fcntl syscall)

CHANGES

@@ -21,6 +21,8 @@
   on Linux, in iob_send, if MSG_MORE is defined, and the request type
     lends itself to it, used sendto/sendmsg with MSG_MORE instead of
     TCP_CORK (saves two syscalls)
+  add io_fd_flags so the caller can tell io_fd whether the socket is blocking
+    (saves one fcntl syscall)
 
 0.29:
   save 8 bytes in taia.h for 64-bit systems

io.h

@@ -78,9 +78,19 @@ int64 io_canwrite();
 /* return next descriptor with expired timeout */
 int64 io_timeouted();
 
+/* 1 means: have IO_FD_CANWRITE, IO_FD_BLOCK and IO_FD_NONBLOCK,
+ * will be incremented if API is extended in the future */
+#define HAVE_IO_FD_FLAGS 1
+enum io_fd_flags {
+  IO_FD_CANWRITE=1,	/* new TCP connection, we know it's writable */
+  IO_FD_BLOCK=2,	/* skip the fcntl, assume fd is set to blocking */
+  IO_FD_NONBLOCK=4,	/* skip the fcntl, assume fd is set to non-blocking */
+};
+
 /* put d on internal data structure, return 1 on success, 0 on error */
 int io_fd(int64 d);		/* use this for sockets before you called connect() or accept() */
 int io_fd_canwrite(int64 d);	/* use this for connected sockets (assumes socket is writable) */
+int io_fd_flags(int64 d,int flags);	/* can be used to tell io_fd to skip one syscall */
 
 void io_setcookie(int64 d,void* cookie);
 void* io_getcookie(int64 d);

io/io_fd.c

@@ -53,12 +53,18 @@ long alt_firstwrite;
 #endif
 
 /* put d on internal data structure, return 1 on success, 0 on error */
-static io_entry* io_fd_internal(int64 d) {
+static io_entry* io_fd_internal(int64 d,int flags) {
   io_entry* e;
 #ifndef __MINGW32__
   long r;
-  if ((r=fcntl(d,F_GETFL,0)) == -1)
-    return 0;	/* file descriptor not open */
+  if ((flags&(IO_FD_BLOCK|IO_FD_NONBLOCK))==0) {
+    if ((r=fcntl(d,F_GETFL,0)) == -1)
+      return 0;	/* file descriptor not open */
+  } else
+    if (flags&IO_FD_NONBLOCK)
+      r=O_NDELAY;
+    else
+      r=0;
 #endif
   /* Problem: we might be the first to use io_fds. We need to make sure
    * we are the only ones to initialize it.  So set io_fds_inited to 2
@@ -146,12 +152,18 @@ static io_entry* io_fd_internal(int64 d) {
 }
 
 int io_fd(int64 d) {
-  io_entry* e=io_fd_internal(d);
+  io_entry* e=io_fd_internal(d,0);
   return !!e;
 }
 
 int io_fd_canwrite(int64 d) {
-  io_entry* e=io_fd_internal(d);
+  io_entry* e=io_fd_internal(d,0);
   if (e) e->canwrite=1;
   return !!e;
 }
+
+int io_fd_flags(int64 d,int flags) {
+  io_entry* e=io_fd_internal(d,flags);
+  if (e && (flags&IO_FD_CANWRITE)) e->canwrite=1;
+  return !!e;
+}