add function to winutil to check for an active internet connection

setup/extensions.py

@@ -143,7 +143,7 @@ def __init__(self, name, sources, **kwargs):
 if iswindows:
     extensions.append(Extension('winutil',
                 ['calibre/utils/windows/winutil.c'],
-                libraries=['shell32', 'setupapi'],
+                libraries=['shell32', 'setupapi', 'wininet'],
                 cflags=['/X']
                 ))
 

src/calibre/utils/windows/winutil.c

@@ -51,11 +51,15 @@ wherever possible in this module.
     script being run. So to replace sys.argv, you should use
     `if len(sys.argv) > 1: sys.argv[1:] = winutil.argv()[1-len(sys.argv):]`
 
+.. function:: internet_connected() -> Return True if there is an active
+   internet connection.
+
 */
 
 
 #define UNICODE
 #include <Windows.h>
+#include <Wininet.h>
 #include <Python.h>
 #include <structseq.h>
 #include <timefuncs.h>
@@ -771,6 +775,15 @@ gettmarg(PyObject *args, struct tm *p)
 	return 1;
 }
 
+static PyObject *
+winutil_internet_connected(PyObject *self, PyObject *args) {
+    DWORD flags;
+    BOOL ans = InternetGetConnectedState(&flags, 0);
+    if (ans) Py_RETURN_TRUE;
+    Py_RETURN_FALSE;
+}
+
+
 static PyObject *
 winutil_strftime(PyObject *self, PyObject *args)
 {
@@ -919,6 +932,10 @@ be a unicode string. Returns unicode strings."
 			"eject_drive(drive_letter)\n\nEject a drive. Raises an exception on failure."
 	},
 
+    {"internet_connected", winutil_internet_connected, METH_VARARGS,
+        "internet_connected()\n\nReturn True if there is an active internet connection"
+    },
+
     {NULL, NULL, 0, NULL}
 };