Add configure option AVOID_WINDOWS_HANDLE

If set, we avoid using Windows I/O HANDLE, which is disallowed in some
versions of the Windows SDK, such as for Windows phones.
QUtil::same_file will always return false in this case. Only applies
to Windows builds.

ChangeLog

@@ -1,5 +1,12 @@
 2019-01-10  Jay Berkenbilt  <ejb@ql.org>
 
+	* Add new configure option --enable-avoid-windows-handle, which
+	causes the symbol AVOID_WINDOWS_HANDLE to be defined. If set, we
+	avoid using Windows I/O HANDLE, which is disallowed in some
+	versions of the Windows SDK, such as for Windows phones.
+	QUtil::same_file will always return false in this case. Only
+	applies to Windows builds.
+
 	* Add new method QPDF::setImmediateCopyFrom. When called on a
 	source QPDF object, streams can be copied FROM that object to
 	other ones without having to keep the source QPDF or its input

autofiles.sums

@@ -1,4 +1,4 @@
-b544741ebe32e6bf555703b4cbedcaef62553da29e3230df4ccb8351900e2378  configure.ac
+8e191dc63d2709fcd089ff62dd022589d12892129616a6036fa7e39833dd5443  configure.ac
 35bc5c645dc42d47f2daeea06f8f3e767c8a1aee6a35eb2b4854fd2ce66c3413  m4/ax_random_device.m4
 37f8897d5f68d7d484e5457832a8f190ddb7507fa2a467cb7ee2be40a4364643  m4/libtool.m4
 e77ebba8361b36f14b4d0927173a034b98c5d05049697a9ded84d85eb99a7990  m4/ltoptions.m4

configure

@@ -756,6 +756,7 @@ enable_libtool_lock
 enable_insecure_random
 enable_os_secure_random
 with_random
+enable_avoid_windows_handle
 enable_external_libs
 with_windows_wordsize
 with_large_file_test_path
@@ -1425,6 +1426,9 @@ Optional Features:
   --enable-os-secure-random
                           whether to try to use OS-provided secure random
                           numbers (default is yes)
+  --enable-avoid-windows-handle
+                          whether to avoid use of HANDLE, useful for some
+                          embedded Windows builds (default is no)
   --enable-external-libs  whether to use external libraries distribution
   --disable-largefile     omit support for large files
   --enable-ld-version-script
@@ -15780,6 +15784,28 @@ _ACEOF
   fi
 
 
+# Check whether --enable-avoid-windows-handle was given.
+if test "${enable_avoid_windows_handle+set}" = set; then :
+  enableval=$enable_avoid_windows_handle; if test "$enableval" = "yes"; then
+      qpdf_AVOID_HANDLE=1;
+    else
+      qpdf_AVOID_HANDLE=0;
+    fi
+else
+  qpdf_AVOID_HANDLE=0
+fi
+
+if test "$qpdf_AVOID_HANDLE" = "1"; then
+   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+
+$as_echo "#define AVOID_WINDOWS_HANDLE 1" >>confdefs.h
+
+else
+   { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
 USE_EXTERNAL_LIBS=0
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for whether to use external libraries distribution" >&5
 $as_echo_n "checking for whether to use external libraries distribution... " >&6; }

configure.ac

@@ -92,6 +92,21 @@ fi
 
 AX_RANDOM_DEVICE
 
+AC_ARG_ENABLE(avoid-windows-handle,
+   AS_HELP_STRING([--enable-avoid-windows-handle],
+                  [whether to avoid use of HANDLE, useful for some embedded Windows builds (default is no)]),
+   [if test "$enableval" = "yes"; then
+      qpdf_AVOID_HANDLE=1;
+    else
+      qpdf_AVOID_HANDLE=0;
+    fi], [qpdf_AVOID_HANDLE=0])
+if test "$qpdf_AVOID_HANDLE" = "1"; then
+   AC_MSG_RESULT(yes)
+   AC_DEFINE([AVOID_WINDOWS_HANDLE], [1], [Whether to avoid use of HANDLE in Windows])
+else
+   AC_MSG_RESULT(no)
+fi
+
 USE_EXTERNAL_LIBS=0
 AC_MSG_CHECKING(for whether to use external libraries distribution)
 AC_ARG_ENABLE(external-libs,

libqpdf/QUtil.cc

@@ -214,13 +214,14 @@ QUtil::same_file(char const* name1, char const* name2)
         return false;
     }
 #ifdef _WIN32
+    bool same = false;
+# ifndef AVOID_WINDOWS_HANDLE
     HANDLE fh1 = CreateFile(name1, GENERIC_READ, FILE_SHARE_READ,
                             NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
     HANDLE fh2 = CreateFile(name2, GENERIC_READ, FILE_SHARE_READ,
                             NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
     BY_HANDLE_FILE_INFORMATION fi1;
     BY_HANDLE_FILE_INFORMATION fi2;
-    bool same = false;
     if ((fh1 != INVALID_HANDLE_VALUE) &&
         (fh2 != INVALID_HANDLE_VALUE) &&
         GetFileInformationByHandle(fh1, &fi1) &&
@@ -239,6 +240,7 @@ QUtil::same_file(char const* name1, char const* name2)
     {
         CloseHandle(fh2);
     }
+# endif
     return same;
 #else
     struct stat st1;

libqpdf/qpdf/qpdf-config.h.in

@@ -1,5 +1,8 @@
 /* libqpdf/qpdf/qpdf-config.h.in.  Generated from configure.ac by autoheader.  */
 
+/* Whether to avoid use of HANDLE in Windows */
+#undef AVOID_WINDOWS_HANDLE
+
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #undef HAVE_DLFCN_H