Add general COM helper functions

2 files changed, 98 insertions, 0 deletions

diff --git a/windns/src/windns/comhelpers.cpp b/windns/src/windns/comhelpers.cpp
new file mode 100644
index 0000000000..dea61b40d9
--- /dev/null
+++ b/windns/src/windns/comhelpers.cpp
@@ -0,0 +1,72 @@
+#include "stdafx.h"
+#include "comhelpers.h"
+#include <algorithm>
+
+_variant_t ComGetProperty(CComPtr<IWbemClassObject> obj, const std::wstring &name)
+{
+	_variant_t val;
+
+	const auto status = obj->Get(name.c_str(), 0, &val, nullptr, nullptr);
+
+	VALIDATE_COM(status, "Retrieve COM property value");
+
+	return val;
+}
+
+_variant_t ComGetPropertyAlways(CComPtr<IWbemClassObject> obj, const std::wstring &name)
+{
+	auto val = ComGetProperty(obj, name);
+
+	if (VT_EMPTY == V_VT(&val) || VT_NULL == V_VT(&val))
+	{
+		throw std::runtime_error("A required COM property value is empty.");
+	}
+
+	return val;
+}
+
+std::wstring ComConvertString(BSTR src)
+{
+	return std::wstring(src, SysStringLen(src));
+}
+
+std::vector<std::wstring> ComConvertStringArray(SAFEARRAY *src)
+{
+	CComSafeArray<BSTR> safeArray(src);
+
+	std::vector<std::wstring> result;
+	result.reserve(safeArray.GetCount());
+
+	for (ULONG i = 0; i < safeArray.GetCount(); ++i)
+	{
+		result.emplace_back(ComConvertString(safeArray.GetAt(i)));
+	}
+
+	return result;
+}
+
+CComSafeArray<BSTR> ComConvertIntoStringArray(const std::vector<std::wstring> &src)
+{
+	CComSafeArray<BSTR> result;
+
+	std::for_each(src.begin(), src.end(), [&](const std::wstring &str)
+	{
+		result.Add(_bstr_t(str.c_str()));
+	});
+
+	return result;
+}
+
+_variant_t ComPackageStringArray(CComSafeArray<BSTR> &src)
+{
+	VARIANT v;
+
+	V_VT(&v) = VT_ARRAY | VT_BSTR;
+	V_ARRAY(&v) = src.Detach();
+
+	_variant_t vv;
+
+	vv.Attach(v);
+
+	return vv;
+}
\ No newline at end of file
diff --git a/windns/src/windns/comhelpers.h b/windns/src/windns/comhelpers.h
new file mode 100644
index 0000000000..67e1a46aea
--- /dev/null
+++ b/windns/src/windns/comhelpers.h
@@ -0,0 +1,26 @@
+#pragma once
+
+#include "libcommon/error.h"
+#include <string>
+#include <vector>
+#include <stdexcept>
+#include <winerror.h>
+#include <atlbase.h>
+#include <comutil.h>
+#include <atlsafe.h>
+#include <wbemidl.h>
+
+#define VALIDATE_COM(status, operation)\
+if(FAILED(status))\
+{\
+	::common::error::Throw(operation, status);\
+}
+
+_variant_t ComGetProperty(CComPtr<IWbemClassObject> obj, const std::wstring &name);
+_variant_t ComGetPropertyAlways(CComPtr<IWbemClassObject> obj, const std::wstring &name);
+std::wstring ComConvertString(BSTR src);
+std::vector<std::wstring> ComConvertStringArray(SAFEARRAY *src);
+CComSafeArray<BSTR> ComConvertIntoStringArray(const std::vector<std::wstring> &src);
+
+// NOTE: This consumes the source variable
+_variant_t ComPackageStringArray(CComSafeArray<BSTR> &src);