1 files changed, 146 insertions, 0 deletions
diff --git a/ipc/mscom/Utils.h b/ipc/mscom/Utils.h
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+++ b/ipc/mscom/Utils.h
@@ -0,0 +1,146 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 mozilla_mscom_Utils_h
+#define mozilla_mscom_Utils_h
+
+#if defined(MOZILLA_INTERNAL_API)
+#  include "nsString.h"
+#endif  // defined(MOZILLA_INTERNAL_API)
+
+#include "mozilla/Attributes.h"
+#include <guiddef.h>
+#include <stdint.h>
+
+struct IStream;
+struct IUnknown;
+
+namespace mozilla {
+namespace mscom {
+namespace detail {
+
+enum class GuidType {
+  CLSID,
+  AppID,
+};
+
+long BuildRegGuidPath(REFGUID aGuid, const GuidType aGuidType, wchar_t* aBuf,
+                      const size_t aBufLen);
+
+}  // namespace detail
+
+bool IsCOMInitializedOnCurrentThread();
+bool IsCurrentThreadMTA();
+bool IsCurrentThreadExplicitMTA();
+bool IsCurrentThreadImplicitMTA();
+#if defined(MOZILLA_INTERNAL_API)
+bool IsCurrentThreadNonMainMTA();
+#endif  // defined(MOZILLA_INTERNAL_API)
+bool IsProxy(IUnknown* aUnknown);
+bool IsValidGUID(REFGUID aCheckGuid);
+uintptr_t GetContainingModuleHandle();
+
+template <size_t N>
+inline long BuildAppidPath(REFGUID aAppId, wchar_t (&aPath)[N]) {
+  return detail::BuildRegGuidPath(aAppId, detail::GuidType::AppID, aPath, N);
+}
+
+template <size_t N>
+inline long BuildClsidPath(REFCLSID aClsid, wchar_t (&aPath)[N]) {
+  return detail::BuildRegGuidPath(aClsid, detail::GuidType::CLSID, aPath, N);
+}
+
+/**
+ * Given a buffer, create a new IStream object.
+ * @param aBuf Buffer containing data to initialize the stream. This parameter
+ *             may be nullptr, causing the stream to be created with aBufLen
+ *             bytes of uninitialized data.
+ * @param aBufLen Length of data in aBuf, or desired stream size if aBuf is
+ *                nullptr.
+ * @param aOutStream Outparam to receive the newly created stream.
+ * @return HRESULT error code.
+ */
+long CreateStream(const uint8_t* aBuf, const uint32_t aBufLen,
+                  IStream** aOutStream);
+
+/**
+ * Length of a stringified GUID as formatted for the registry, i.e. including
+ * curly-braces and dashes.
+ */
+constexpr size_t kGuidRegFormatCharLenInclNul = 39;
+
+#if defined(MOZILLA_INTERNAL_API)
+/**
+ * Checks the registry to see if |aClsid| is a thread-aware in-process server.
+ *
+ * In DCOM, an in-process server is a server that is implemented inside a DLL
+ * that is loaded into the client's process for execution. If |aClsid| declares
+ * itself to be a local server (that is, a server that resides in another
+ * process), this function returns false.
+ *
+ * For the server to be thread-aware, its registry entry must declare a
+ * ThreadingModel that is one of "Free", "Both", or "Neutral". If the threading
+ * model is "Apartment" or some other, invalid value, the class is treated as
+ * being single-threaded.
+ *
+ * NB: This function cannot check CLSIDs that were registered via manifests,
+ * as unfortunately there is not a documented API available to query for those.
+ * This should not be an issue for most CLSIDs that Gecko is interested in, as
+ * we typically instantiate system CLSIDs which are available in the registry.
+ *
+ * @param aClsid The CLSID of the COM class to be checked.
+ * @return true if the class meets the above criteria, otherwise false.
+ */
+bool IsClassThreadAwareInprocServer(REFCLSID aClsid);
+
+void GUIDToString(REFGUID aGuid, nsAString& aOutString);
+
+/**
+ * Converts an IID to a human-readable string for the purposes of diagnostic
+ * tools such as the profiler. For some special cases, we output a friendly
+ * string that describes the purpose of the interface. If no such description
+ * exists, we simply fall back to outputting the IID as a string formatted by
+ * GUIDToString().
+ */
+void DiagnosticNameForIID(REFIID aIid, nsACString& aOutString);
+#else
+void GUIDToString(REFGUID aGuid,
+                  wchar_t (&aOutBuf)[kGuidRegFormatCharLenInclNul]);
+#endif  // defined(MOZILLA_INTERNAL_API)
+
+/**
+ * Execute cleanup code when going out of scope if a condition is met.
+ * This is useful when, for example, particular cleanup needs to be performed
+ * whenever a call returns a failure HRESULT.
+ * Both the condition and cleanup code are provided as functions (usually
+ * lambdas).
+ */
+template <typename CondFnT, typename ExeFnT>
+class MOZ_RAII ExecuteWhen final {
+ public:
+  ExecuteWhen(CondFnT& aCondFn, ExeFnT& aExeFn)
+      : mCondFn(aCondFn), mExeFn(aExeFn) {}
+
+  ~ExecuteWhen() {
+    if (mCondFn()) {
+      mExeFn();
+    }
+  }
+
+  ExecuteWhen(const ExecuteWhen&) = delete;
+  ExecuteWhen(ExecuteWhen&&) = delete;
+  ExecuteWhen& operator=(const ExecuteWhen&) = delete;
+  ExecuteWhen& operator=(ExecuteWhen&&) = delete;
+
+ private:
+  CondFnT& mCondFn;
+  ExeFnT& mExeFn;
+};
+
+}  // namespace mscom
+}  // namespace mozilla
+
+#endif  // mozilla_mscom_Utils_h