reduce dependency on ghcconfig.h

[ghc-base.git] / cbits / inputReady.c

diff --git a/cbits/inputReady.c b/cbits/inputReady.c
index 79a605a..f827fe5 100644 (file)
--- a/cbits/inputReady.c
+++ b/cbits/inputReady.c
@@ -1,14 +1,12 @@
 /* 
- * (c) The GRASP/AQUA Project, Glasgow University, 1994-1998
+ * (c) The GRASP/AQUA Project, Glasgow University, 1994-2002
  *
- * $Id: inputReady.c,v 1.3 2001/08/17 12:50:34 simonmar Exp $
- *
- * hReady Runtime Support
+ * hWaitForInput Runtime Support
  */
 
 /* select and supporting types is not Posix */
 /* #include "PosixSource.h" */
-#include "HsCore.h"
+#include "HsBase.h"
 
 /*
  * inputReady(fd) checks to see whether input is available on the file
@@ -16,35 +14,78 @@
  * *character* from this file object without blocking?'
  */
 int
-inputReady(int fd, int msecs)
+inputReady(int fd, int msecs, int isSock)
 {
-#ifndef mingw32_TARGET_OS
-    int maxfd, ready;
-    fd_set rfd;
-    struct timeval tv;
-#endif
-
-#ifdef mingw32_TARGET_OS
-    return 1;
+    if 
+#if defined(_MSC_VER) || defined(__MINGW32__) || defined(_WIN32)
+    ( isSock ) {
 #else
-    FD_ZERO(&rfd);
-    FD_SET(fd, &rfd);
-
-    /* select() will consider the descriptor set in the range of 0 to
-     * (maxfd-1) 
-     */
-    maxfd = fd + 1;
-    tv.tv_sec  = msecs / 1000;
-    tv.tv_usec = msecs % 1000;
-
-    while ((ready = select(maxfd, &rfd, NULL, NULL, &tv)) < 0 ) {
-      if (errno != EINTR ) {
-          return -1;
-      }
-   }
+    ( 1 ) {
+#endif
+       int maxfd, ready;
+       fd_set rfd;
+       struct timeval tv;
+       
+       FD_ZERO(&rfd);
+       FD_SET(fd, &rfd);
+       
+       /* select() will consider the descriptor set in the range of 0 to
+        * (maxfd-1) 
+        */
+       maxfd = fd + 1;
+       tv.tv_sec  = msecs / 1000;
+       tv.tv_usec = (msecs % 1000) * 1000;
+       
+       while ((ready = select(maxfd, &rfd, NULL, NULL, &tv)) < 0 ) {
+           if (errno != EINTR ) {
+               return -1;
+           }
+       }
+       
+       /* 1 => Input ready, 0 => not ready, -1 => error */
+       return (ready);
+    }
+#if defined(_MSC_VER) || defined(__MINGW32__) || defined(_WIN32)
+    else {
+       DWORD rc;
+       HANDLE hFile = (HANDLE)_get_osfhandle(fd);
+       DWORD avail;
 
-    /* 1 => Input ready, 0 => not ready, -1 => error */
-    return (ready);
+       // WaitForMultipleObjects() works for Console input, but it
+       // doesn't work for pipes (it always returns WAIT_OBJECT_0
+       // even when no data is available).  There doesn't seem to be
+       // an easy way to distinguish the two kinds of HANDLE, so we
+       // try to detect pipe input first, and if that fails we try
+       // WaitForMultipleObjects().
+       //
+       rc = PeekNamedPipe( hFile, NULL, 0, NULL, &avail, NULL );
+       if (rc != 0) {
+           if (avail != 0) {
+               return 1;
+           } else {
+               return 0;
+           }
+       } else {
+           rc = GetLastError();
+           if (rc == ERROR_BROKEN_PIPE) {
+               return 1; // this is probably what we want
+           }
+           if (rc != ERROR_INVALID_HANDLE) {
+               return -1;
+           }
+       }
 
+       rc = WaitForMultipleObjects( 1,
+                                    &hFile,
+                                    TRUE,   /* wait all */
+                                    msecs); /*millisecs*/
+       
+       /* 1 => Input ready, 0 => not ready, -1 => error */
+       switch (rc) {
+       case WAIT_TIMEOUT: return 0;
+       case WAIT_OBJECT_0: return 1;
+       default: return -1;
+       }
+    }
 #endif
-}
+}