X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=cbits%2FinputReady.c;h=2949e9494bbef90696f4c1d613018dc5b9f3cf30;hb=5031aad924a8b70b5fc4fe4bb1321c007afcab21;hp=6585de91cc71c5ab5cdabeac241ae4ee58a0bba9;hpb=260e7f2ed9a43c6ecf5a556d77817f39ed2893ab;p=ghc-base.git

diff --git a/cbits/inputReady.c b/cbits/inputReady.c
index 6585de9..2949e94 100644
--- 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 1.4 2001/12/21 15:07:26 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
@@ -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
-  }}
+}