import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

ipc/mscom/ProxyStream.cpp

@@ -0,0 +1,202 @@
+/* -*- 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/. */
+
+#include "DynamicallyLinkedFunctionPtr.h"
+#include "mozilla/mscom/EnsureMTA.h"
+#include "mozilla/mscom/ProxyStream.h"
+#include "mozilla/mscom/Utils.h"
+
+#include "mozilla/Move.h"
+
+#include <windows.h>
+#include <objbase.h>
+#include <shlwapi.h>
+
+namespace mozilla {
+namespace mscom {
+
+ProxyStream::ProxyStream()
+  : mGlobalLockedBuf(nullptr)
+  , mHGlobal(nullptr)
+  , mBufSize(0)
+{
+}
+
+// GetBuffer() fails with this variant, but that's okay because we're just
+// reconstructing the stream from a buffer anyway.
+ProxyStream::ProxyStream(const BYTE* aInitBuf, const int aInitBufSize)
+  : mStream(InitStream(aInitBuf, static_cast<const UINT>(aInitBufSize)))
+  , mGlobalLockedBuf(nullptr)
+  , mHGlobal(nullptr)
+  , mBufSize(aInitBufSize)
+{
+  if (!aInitBufSize) {
+    // We marshaled a nullptr. Nothing else to do here.
+    return;
+  }
+  // NB: We can't check for a null mStream until after we have checked for
+  // the zero aInitBufSize above. This is because InitStream will also fail
+  // in that case, even though marshaling a nullptr is allowable.
+  MOZ_ASSERT(mStream);
+  if (!mStream) {
+    return;
+  }
+
+  // We need to convert to an interface here otherwise we mess up const
+  // correctness with IPDL. We'll request an IUnknown and then QI the
+  // actual interface later.
+
+  auto marshalFn = [&]() -> void
+  {
+    IUnknown* rawUnmarshaledProxy = nullptr;
+    // OK to forget mStream when calling into this function because the stream
+    // gets released even if the unmarshaling part fails.
+    DebugOnly<HRESULT> hr =
+      ::CoGetInterfaceAndReleaseStream(mStream.forget().take(), IID_IUnknown,
+                                       (void**)&rawUnmarshaledProxy);
+    MOZ_ASSERT(SUCCEEDED(hr));
+    mUnmarshaledProxy.reset(rawUnmarshaledProxy);
+  };
+
+  if (XRE_IsParentProcess()) {
+    // We'll marshal this stuff directly using the current thread, therefore its
+    // proxy will reside in the same apartment as the current thread.
+    marshalFn();
+  } else {
+    // When marshaling in child processes, we want to force the MTA.
+    EnsureMTA mta(marshalFn);
+  }
+}
+
+already_AddRefed<IStream>
+ProxyStream::InitStream(const BYTE* aInitBuf, const UINT aInitBufSize)
+{
+  // Need to link to this as ordinal 12 for Windows XP
+  static DynamicallyLinkedFunctionPtr<decltype(&::SHCreateMemStream)>
+    pSHCreateMemStream(L"shlwapi.dll", reinterpret_cast<const char*>(12));
+  if (!pSHCreateMemStream) {
+    return nullptr;
+  }
+  return already_AddRefed<IStream>(pSHCreateMemStream(aInitBuf, aInitBufSize));
+}
+
+ProxyStream::ProxyStream(ProxyStream&& aOther)
+{
+  *this = mozilla::Move(aOther);
+}
+
+ProxyStream&
+ProxyStream::operator=(ProxyStream&& aOther)
+{
+  mStream = mozilla::Move(aOther.mStream);
+  mGlobalLockedBuf = aOther.mGlobalLockedBuf;
+  aOther.mGlobalLockedBuf = nullptr;
+  mHGlobal = aOther.mHGlobal;
+  aOther.mHGlobal = nullptr;
+  mBufSize = aOther.mBufSize;
+  aOther.mBufSize = 0;
+  return *this;
+}
+
+ProxyStream::~ProxyStream()
+{
+  if (mHGlobal && mGlobalLockedBuf) {
+    DebugOnly<BOOL> result = ::GlobalUnlock(mHGlobal);
+    MOZ_ASSERT(!result && ::GetLastError() == NO_ERROR);
+    // ::GlobalFree() is called implicitly when mStream is released
+  }
+}
+
+const BYTE*
+ProxyStream::GetBuffer(int& aReturnedBufSize) const
+{
+  aReturnedBufSize = 0;
+  if (!mStream) {
+    return nullptr;
+  }
+  if (!mGlobalLockedBuf) {
+    return nullptr;
+  }
+  aReturnedBufSize = mBufSize;
+  return mGlobalLockedBuf;
+}
+
+bool
+ProxyStream::GetInterface(REFIID aIID, void** aOutInterface) const
+{
+  // We should not have a locked buffer on this side
+  MOZ_ASSERT(!mGlobalLockedBuf);
+  MOZ_ASSERT(aOutInterface);
+
+  if (!aOutInterface) {
+    return false;
+  }
+
+  if (!mUnmarshaledProxy) {
+    *aOutInterface = nullptr;
+    return true;
+  }
+
+  HRESULT hr = E_UNEXPECTED;
+  auto qiFn = [&]() -> void
+  {
+    hr = mUnmarshaledProxy->QueryInterface(aIID, aOutInterface);
+  };
+
+  if (XRE_IsParentProcess()) {
+    qiFn();
+  } else {
+    // mUnmarshaledProxy requires that we execute this in the MTA
+    EnsureMTA mta(qiFn);
+  }
+  return SUCCEEDED(hr);
+}
+
+ProxyStream::ProxyStream(REFIID aIID, IUnknown* aObject)
+  : mGlobalLockedBuf(nullptr)
+  , mHGlobal(nullptr)
+  , mBufSize(0)
+{
+  RefPtr<IStream> stream;
+  HGLOBAL hglobal = NULL;
+
+  auto marshalFn = [&]() -> void
+  {
+    HRESULT hr = ::CreateStreamOnHGlobal(nullptr, TRUE, getter_AddRefs(stream));
+    if (FAILED(hr)) {
+      return;
+    }
+
+    hr = ::CoMarshalInterface(stream, aIID, aObject, MSHCTX_LOCAL, nullptr,
+                              MSHLFLAGS_NORMAL);
+    if (FAILED(hr)) {
+      return;
+    }
+
+    hr = ::GetHGlobalFromStream(stream, &hglobal);
+    MOZ_ASSERT(SUCCEEDED(hr));
+  };
+
+  if (XRE_IsParentProcess()) {
+    // We'll marshal this stuff directly using the current thread, therefore its
+    // stub will reside in the same apartment as the current thread.
+    marshalFn();
+  } else {
+    // When marshaling in child processes, we want to force the MTA.
+    EnsureMTA mta(marshalFn);
+  }
+
+  mStream = mozilla::Move(stream);
+  if (hglobal) {
+    mGlobalLockedBuf = reinterpret_cast<BYTE*>(::GlobalLock(hglobal));
+    mHGlobal = hglobal;
+    mBufSize = static_cast<int>(::GlobalSize(hglobal));
+  }
+}
+
+} // namespace mscom
+} // namespace mozilla
+