home: hub: zuo

Info  •  Files  •  Log

support non-blocking input on Windows for non-consoles

Related to #11

--- a/zuo-doc/lang-zuo.scrbl

+++ b/zuo-doc/lang-zuo.scrbl

@@ -1007,6 +1007,8 @@

 than @racket[amount] but at least one byte. The result can be an empty

 string only if @racket[amount] is @racket[0] or @racket['avail].

+On Windows, @racket['avail] mode is not supported for console input.

+

 @history[#:changed "1.5" @elem{Report @racket[eof] when available in @racket['avail] mode.}]}

 @defproc[(fd-write [handle handle?] [str string?]) void?]{

--- a/zuo.c

+++ b/zuo.c

@@ -4148,9 +4148,10 @@

 static zuo_t *zuo_drain(zuo_raw_handle_t fd, zuo_int_t amount) {

   /* amount as -1 => read until EOF

-     amount as -2 => non-blocking read on Unix */

+     amount as -2 => non-blocking read */

   zuo_t *s;

   zuo_int_t sz = 256, offset = 0;

+  int nonblock = (amount == -2);

   if ((amount >= 0) && (sz > amount))

     sz = amount;

@@ -4162,7 +4163,7 @@

     if (amt > 4096) amt = 4096;

 #ifdef ZUO_UNIX

     {

-      int nonblock = (amount == -2), old_fl, r;

+      int old_fl, r;

       if (nonblock) {

         EINTR_RETRY(old_fl = fcntl(fd, F_GETFL, 0));

@@ -4186,6 +4187,24 @@

     }

 #endif

 #ifdef ZUO_WINDOWS

+    if (nonblock) {

+      DWORD type = GetFileType(fd);

+      if (type == FILE_TYPE_CHAR)

+        zuo_fail("non-blocking reads are not supported for a console");

+      if (type == FILE_TYPE_PIPE) {

+	DWORD avail;

+	ZUO_STRING_PTR(s)[offset] = 0;

+	ZUO_STRING_LEN(s) = offset;

+        if (!PeekNamedPipe(fd, NULL, 0, NULL, &avail, NULL)) {

+	  if (GetLastError() == ERROR_BROKEN_PIPE)

+	    return z.o_eof;

+          zuo_fail("error checking pipe");

+	}

+        if (avail == 0)

+	  return s;

+      }

+    }

+

     {

       DWORD dgot;

       if (!ReadFile(fd, ZUO_STRING_PTR(s) + offset, amt, &dgot, NULL)) {

@@ -4491,14 +4510,9 @@

     zuo_fail_arg(who, "open input file descriptor", fd_h);

   if (amount != z.o_eof) {

     if ((amount->tag == zuo_symbol_tag)

-        && (amount == zuo_symbol("avail"))) {

-#ifdef ZUO_UNIX

+        && (amount == zuo_symbol("avail")))

       amt = -2;

-#endif

-#ifdef ZUO_WINDOWS

-      zuo_fail1w(who, "non-blocking reads are not supported for file descriptor", fd_h);

-#endif

-    } else if ((amount->tag == zuo_integer_tag)

+    else if ((amount->tag == zuo_integer_tag)

              && (ZUO_INT_I(amount) >= 0))

       amt = ZUO_INT_I(amount);

     else