Import Data.ByteString.Lazy, improve ByteString Fusion, and resync with FPS head

[haskell-directory.git] / cbits / inputReady.c

diff --git a/cbits/inputReady.c b/cbits/inputReady.c
index 63233ec..2949e94 100644 (file)
--- a/cbits/inputReady.c
+++ b/cbits/inputReady.c
@@ -1,9 +1,7 @@
 /* 
- * (c) The GRASP/AQUA Project, Glasgow University, 1994-1998
+ * (c) The GRASP/AQUA Project, Glasgow University, 1994-2002
  *
- * $Id: inputReady.c,v 1.5 2002/02/07 11:13:30 simonmar Exp $
- *
- * hReady Runtime Support
+ * hWaitForInput Runtime Support
  */
 
 /* select and supporting types is not Posix */
@@ -18,51 +16,76 @@
 int
 inputReady(int fd, int msecs, int isSock)
 {
-  if 
-#ifndef mingw32_TARGET_OS
+    if 
+#ifndef mingw32_HOST_OS
     ( 1 ) {
 #else
     ( isSock ) {
 #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;
+       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);
+    }
+#ifdef mingw32_HOST_OS
+    else {
+       DWORD rc;
+       HANDLE hFile = (HANDLE)_get_osfhandle(fd);
+       DWORD avail;
 
-    while ((ready = select(maxfd, &rfd, NULL, NULL, &tv)) < 0 ) {
-      if (errno != EINTR ) {
-          return -1;
-      }
-   }
+       // 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;
+           }
+       }
 
-    /* 1 => Input ready, 0 => not ready, -1 => error */
-    return (ready);
-#ifdef mingw32_TARGET_OS
-    } else {
-      DWORD rc;
-      HANDLE hFile = (HANDLE)_get_osfhandle(fd);
-    
-      rc = MsgWaitForMultipleObjects( 1,
-                                     &hFile,
-                                     FALSE, /* wait all */
-                                     msecs, /*millisecs*/
-                                     QS_ALLEVENTS);
-    
-      /* 1 => Input ready, 0 => not ready, -1 => error */
-      switch (rc) {
-       case WAIT_TIMEOUT: return 0;
-       case WAIT_OBJECT_0: return 1;
-       default: 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
-  }}
+}