tdf#114635: reimplement TWAIN-based scan using 32-bit shim on Windows

Since TWAIN is only actually available as 32-bit component on Windows,
to use it in a 64-bit program, we need a 32-bit shim program that does
all actual communication with TWAIN subsystem.

This change reimplements TWAIN implementation to be a separate 32-bit
process. Image is transfered from the shim to main program using file
mapping API.

This reverts most of commit 585d9806961342e95f7318fb947bd31e9f86dee0.
64-bit LibreOffice doesn't bundle TWAIN DSM library now. TWAIN DSM
source code is still used for TWAIN headers.

Change-Id: I46f178ad36acd97a9eff156624b99036fcbb83f8
Reviewed-on: https://gerrit.libreoffice.org/65688
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

1 files changed, 70 insertions, 0 deletions

diff --git a/extensions/source/scanner/twain32shim.hxx b/extensions/source/scanner/twain32shim.hxx
new file mode 100644
index 000000000000..b72df438d596
--- /dev/null
+++ b/extensions/source/scanner/twain32shim.hxx
@@ -0,0 +1,70 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ */
+
+#ifndef INCLUDED_EXTENSIONS_SOURCE_SCANNER_TWAIN32SHIM_HXX
+#define INCLUDED_EXTENSIONS_SOURCE_SCANNER_TWAIN32SHIM_HXX
+
+#include <prewin.h>
+#include <postwin.h>
+#include <exception>
+#include <string>
+#include <sstream>
+#include <iomanip>
+
+// Don't use WM_USER
+
+// Notifications from shim to parent; wParam = event id
+#define WM_TWAIN_EVENT (WM_USER + 1)
+
+// lParam is HWND
+#define TWAIN_EVENT_NOTIFYHWND 0
+
+// lParam is result (bool indicating success)
+#define TWAIN_EVENT_REQUESTRESULT 1
+
+// lParam is ignored
+#define TWAIN_EVENT_NONE 10
+#define TWAIN_EVENT_QUIT 11
+#define TWAIN_EVENT_SCANNING 12
+
+// lParam is HANDLE to shared file mapping valid in context of parent process
+#define TWAIN_EVENT_XFER 13
+
+// Requests from parent to shim; wParam = request id
+#define WM_TWAIN_REQUEST (WM_USER + 2)
+
+#define TWAIN_REQUEST_QUIT 0 // Destroy()
+#define TWAIN_REQUEST_SELECTSOURCE 1
+#define TWAIN_REQUEST_INITXFER 2
+
+// messages starting from this are not to be used for interprocess communications
+#define WM_SHIM_INTERNAL (WM_USER + 200)
+
+template <typename IntType> std::string Num2Hex(IntType n)
+{
+    std::stringstream sMsg;
+    sMsg << "0x" << std::uppercase << std::setfill('0') << std::setw(sizeof(n) * 2) << std::hex
+         << n;
+    return sMsg.str();
+}
+
+void ThrowWin32Error(const char* sFunc, DWORD nWin32Error)
+{
+    std::stringstream sMsg;
+    sMsg << sFunc << " failed with Win32 error code " << Num2Hex(nWin32Error) << "!";
+
+    throw std::exception(sMsg.str().c_str());
+}
+
+void ThrowLastError(const char* sFunc) { ThrowWin32Error(sFunc, GetLastError()); }
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */