Switching to IDispatch::Invoke when calling Omaha interfaces.

remoting/base/dispatch_win.h

+// This file was GENERATED by command:
+//     pump.py dispatch_win.h.pump
+// DO NOT EDIT BY HAND!!!

[Wez, 2012/06/13 00:34:36]

I'm going to assume you haven't edited by hand, and not review by eye.

+
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef REMOTING_BASE_IDISPATCH_DRIVER_WIN_H_
+#define REMOTING_BASE_IDISPATCH_DRIVER_WIN_H_
+
+#include <oaidl.h>
+
+#include "base/basictypes.h"
+#include "base/template_util.h"
+#include "base/win/scoped_variant.h"
+
+namespace remoting {
+
+namespace dispatch {
+
+namespace internal {
+
+// |is_param| is used to test whether the passed parameters are either constant
+// references to |VARIANT| structures (input parameters) or pointers to
+// |VARIANT| structures (output parameters).
+template <typename T> struct is_param : base::false_type {};
+template <> struct is_param<VARIANT> : base::true_type {};
+template <> struct is_param<base::win::ScopedVariant> : base::true_type {};
+template <> struct is_param<VARIANT*> : base::true_type {};
+
+// |ScopedVariantArg| is used to cleanup local copies of |VARIANT| parameters
+// in case of an error. It should be possible to cast a pointer to a vector of
+// |ScopedVariantArg| to a pointer to a vector of |VARIANTARG| strcutures.
+class ScopedVariantArg : public VARIANTARG {
+ public:
+  ScopedVariantArg() {
+    vt = VT_EMPTY;
+  }
+
+  ~ScopedVariantArg() {
+    VariantClear(this);
+  }
+
+  // Marshall() routines copy an input parameter to a VARIANTARG structure so
+  // that it can be passed to IDispatch::Invoke.
+  template <typename T>
+  HRESULT Marshall(const T& param) {
+    CHECK(false);
+    return E_FAIL;
+  }
+
+  template <>
+  HRESULT Marshall<VARIANT>(const VARIANT& param) {
+    return VariantCopy(this, &param);
+  }
+
+  template <>
+  HRESULT Marshall<base::win::ScopedVariant>(
+      const base::win::ScopedVariant& param) {
+    return VariantCopy(this, &param);
+  }
+
+  template <>
+  HRESULT Marshall<VARIANT*>(VARIANT* const & param) {
+    return S_OK;
+  }
+
+  // Unmarshall() routines moves an output parameter from a VARIANTARG structure
+  // to the location specified by the caller.
+  template <typename T>
+  void Unmarshall(const T& param_out) {
+    CHECK(false);
+  }
+
+  template <>
+  void Unmarshall<VARIANT>(const VARIANT& param_out) {
+  }
+
+  template <>
+  void Unmarshall<base::win::ScopedVariant>(
+      const base::win::ScopedVariant& param_out) {
+  }
+
+  template <>
+  void Unmarshall<VARIANT*>(VARIANT* const & param_out) {
+    *param_out = *this;
+    vt = VT_EMPTY;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ScopedVariantArg);
+};
+
+// Make sure the layout of |VARIANTARG| and |ScopedVariantArg| is identical.
+COMPILE_ASSERT(sizeof(ScopedVariantArg) == sizeof(VARIANTARG),
+               scoped_variant_arg_should_not_add_data_members);
+
+}  // namespace internal
+
+// Invoke() is a convenience wrapper for IDispatch::Invoke. It takes care of
+// calling the desired method by its ID and implements logic for passing
+// a variable number of in/out parameters to the called method.
+//
+// Current limitations:
+//   - in_out parameters are not supported.
+//   - more than 7 parameters are not supported.
+//   - the method ID cannot be cached and reused.
+//   - VARIANT is the only supported parameter type at the moment.
+
+HRESULT Invoke(IDispatch* object,
+               LPOLESTR name,
+               WORD flags,
+               VARIANT* const & result_out) {
+
+  // Retrieve the ID of the method to be called.
+  DISPID disp_id;
+  HRESULT hr = object->GetIDsOfNames(IID_NULL, &name, 1, LOCALE_USER_DEFAULT,
+                                     &disp_id);
+  if (FAILED(hr))
+    return hr;
+
+  // Request the return value if asked by the caller.
+  internal::ScopedVariantArg result;
+  VARIANT* disp_result = NULL;
+  if (result_out != NULL)
+    disp_result = &result;
+
+
+  // Invoke the method.
+  DISPPARAMS disp_params = { NULL, NULL, 0, 0 };
+  hr = object->Invoke(disp_id, IID_NULL, LOCALE_USER_DEFAULT, flags,
+                      &disp_params, disp_result, NULL, NULL);
+  if (FAILED(hr))
+    return hr;
+
+
+  // Unmarshall the return value.
+  if (result_out != NULL)
+    result.Unmarshall(result_out);
+
+  return S_OK;
+}
+
+template <typename P1>
+HRESULT Invoke(IDispatch* object,
+               LPOLESTR name,
+               WORD flags,
+               const P1& p1,
+               VARIANT* const & result_out) {
+  COMPILE_ASSERT(internal::is_param<P1>::value, parameters_must_be_variants);
+
+  // Retrieve the ID of the method to be called.
+  DISPID disp_id;
+  HRESULT hr = object->GetIDsOfNames(IID_NULL, &name, 1, LOCALE_USER_DEFAULT,
+                                     &disp_id);
+  if (FAILED(hr))
+    return hr;
+
+  // Request the return value if asked by the caller.
+  internal::ScopedVariantArg result;
+  VARIANT* disp_result = NULL;
+  if (result_out != NULL)
+    disp_result = &result;
+
+  // Marshal the parameters into an array of VARIANT structures.
+  internal::ScopedVariantArg disp_args[1];
+  hr = disp_args[1 - 1].Marshall(p1);
+  if (FAILED(hr))
+    return hr;
+
+  // Invoke the method.
+  DISPPARAMS disp_params = { disp_args, NULL, 1, 0 };
+  hr = object->Invoke(disp_id, IID_NULL, LOCALE_USER_DEFAULT, flags,
+                      &disp_params, disp_result, NULL, NULL);
+  if (FAILED(hr))
+    return hr;
+
+  // Unmarshall the parameters.
+  disp_args[1 - 1].Unmarshall(p1);
+
+  // Unmarshall the return value.
+  if (result_out != NULL)
+    result.Unmarshall(result_out);
+
+  return S_OK;
+}
+
+template <typename P1, typename P2>
+HRESULT Invoke(IDispatch* object,
+               LPOLESTR name,
+               WORD flags,
+               const P1& p1,
+               const P2& p2,
+               VARIANT* const & result_out) {
+  COMPILE_ASSERT(internal::is_param<P1>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P2>::value, parameters_must_be_variants);
+
+  // Retrieve the ID of the method to be called.
+  DISPID disp_id;
+  HRESULT hr = object->GetIDsOfNames(IID_NULL, &name, 1, LOCALE_USER_DEFAULT,
+                                     &disp_id);
+  if (FAILED(hr))
+    return hr;
+
+  // Request the return value if asked by the caller.
+  internal::ScopedVariantArg result;
+  VARIANT* disp_result = NULL;
+  if (result_out != NULL)
+    disp_result = &result;
+
+  // Marshal the parameters into an array of VARIANT structures.
+  internal::ScopedVariantArg disp_args[2];
+  hr = disp_args[2 - 1].Marshall(p1);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[2 - 2].Marshall(p2);
+  if (FAILED(hr))
+    return hr;
+
+  // Invoke the method.
+  DISPPARAMS disp_params = { disp_args, NULL, 2, 0 };
+  hr = object->Invoke(disp_id, IID_NULL, LOCALE_USER_DEFAULT, flags,
+                      &disp_params, disp_result, NULL, NULL);
+  if (FAILED(hr))
+    return hr;
+
+  // Unmarshall the parameters.
+  disp_args[2 - 1].Unmarshall(p1);
+  disp_args[2 - 2].Unmarshall(p2);
+
+  // Unmarshall the return value.
+  if (result_out != NULL)
+    result.Unmarshall(result_out);
+
+  return S_OK;
+}
+
+template <typename P1, typename P2, typename P3>
+HRESULT Invoke(IDispatch* object,
+               LPOLESTR name,
+               WORD flags,
+               const P1& p1,
+               const P2& p2,
+               const P3& p3,
+               VARIANT* const & result_out) {
+  COMPILE_ASSERT(internal::is_param<P1>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P2>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P3>::value, parameters_must_be_variants);
+
+  // Retrieve the ID of the method to be called.
+  DISPID disp_id;
+  HRESULT hr = object->GetIDsOfNames(IID_NULL, &name, 1, LOCALE_USER_DEFAULT,
+                                     &disp_id);
+  if (FAILED(hr))
+    return hr;
+
+  // Request the return value if asked by the caller.
+  internal::ScopedVariantArg result;
+  VARIANT* disp_result = NULL;
+  if (result_out != NULL)
+    disp_result = &result;
+
+  // Marshal the parameters into an array of VARIANT structures.
+  internal::ScopedVariantArg disp_args[3];
+  hr = disp_args[3 - 1].Marshall(p1);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[3 - 2].Marshall(p2);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[3 - 3].Marshall(p3);
+  if (FAILED(hr))
+    return hr;
+
+  // Invoke the method.
+  DISPPARAMS disp_params = { disp_args, NULL, 3, 0 };
+  hr = object->Invoke(disp_id, IID_NULL, LOCALE_USER_DEFAULT, flags,
+                      &disp_params, disp_result, NULL, NULL);
+  if (FAILED(hr))
+    return hr;
+
+  // Unmarshall the parameters.
+  disp_args[3 - 1].Unmarshall(p1);
+  disp_args[3 - 2].Unmarshall(p2);
+  disp_args[3 - 3].Unmarshall(p3);
+
+  // Unmarshall the return value.
+  if (result_out != NULL)
+    result.Unmarshall(result_out);
+
+  return S_OK;
+}
+
+template <typename P1, typename P2, typename P3, typename P4>
+HRESULT Invoke(IDispatch* object,
+               LPOLESTR name,
+               WORD flags,
+               const P1& p1,
+               const P2& p2,
+               const P3& p3,
+               const P4& p4,
+               VARIANT* const & result_out) {
+  COMPILE_ASSERT(internal::is_param<P1>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P2>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P3>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P4>::value, parameters_must_be_variants);
+
+  // Retrieve the ID of the method to be called.
+  DISPID disp_id;
+  HRESULT hr = object->GetIDsOfNames(IID_NULL, &name, 1, LOCALE_USER_DEFAULT,
+                                     &disp_id);
+  if (FAILED(hr))
+    return hr;
+
+  // Request the return value if asked by the caller.
+  internal::ScopedVariantArg result;
+  VARIANT* disp_result = NULL;
+  if (result_out != NULL)
+    disp_result = &result;
+
+  // Marshal the parameters into an array of VARIANT structures.
+  internal::ScopedVariantArg disp_args[4];
+  hr = disp_args[4 - 1].Marshall(p1);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[4 - 2].Marshall(p2);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[4 - 3].Marshall(p3);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[4 - 4].Marshall(p4);
+  if (FAILED(hr))
+    return hr;
+
+  // Invoke the method.
+  DISPPARAMS disp_params = { disp_args, NULL, 4, 0 };
+  hr = object->Invoke(disp_id, IID_NULL, LOCALE_USER_DEFAULT, flags,
+                      &disp_params, disp_result, NULL, NULL);
+  if (FAILED(hr))
+    return hr;
+
+  // Unmarshall the parameters.
+  disp_args[4 - 1].Unmarshall(p1);
+  disp_args[4 - 2].Unmarshall(p2);
+  disp_args[4 - 3].Unmarshall(p3);
+  disp_args[4 - 4].Unmarshall(p4);
+
+  // Unmarshall the return value.
+  if (result_out != NULL)
+    result.Unmarshall(result_out);
+
+  return S_OK;
+}
+
+template <typename P1, typename P2, typename P3, typename P4, typename P5>
+HRESULT Invoke(IDispatch* object,
+               LPOLESTR name,
+               WORD flags,
+               const P1& p1,
+               const P2& p2,
+               const P3& p3,
+               const P4& p4,
+               const P5& p5,
+               VARIANT* const & result_out) {
+  COMPILE_ASSERT(internal::is_param<P1>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P2>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P3>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P4>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P5>::value, parameters_must_be_variants);
+
+  // Retrieve the ID of the method to be called.
+  DISPID disp_id;
+  HRESULT hr = object->GetIDsOfNames(IID_NULL, &name, 1, LOCALE_USER_DEFAULT,
+                                     &disp_id);
+  if (FAILED(hr))
+    return hr;
+
+  // Request the return value if asked by the caller.
+  internal::ScopedVariantArg result;
+  VARIANT* disp_result = NULL;
+  if (result_out != NULL)
+    disp_result = &result;
+
+  // Marshal the parameters into an array of VARIANT structures.
+  internal::ScopedVariantArg disp_args[5];
+  hr = disp_args[5 - 1].Marshall(p1);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[5 - 2].Marshall(p2);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[5 - 3].Marshall(p3);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[5 - 4].Marshall(p4);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[5 - 5].Marshall(p5);
+  if (FAILED(hr))
+    return hr;
+
+  // Invoke the method.
+  DISPPARAMS disp_params = { disp_args, NULL, 5, 0 };
+  hr = object->Invoke(disp_id, IID_NULL, LOCALE_USER_DEFAULT, flags,
+                      &disp_params, disp_result, NULL, NULL);
+  if (FAILED(hr))
+    return hr;
+
+  // Unmarshall the parameters.
+  disp_args[5 - 1].Unmarshall(p1);
+  disp_args[5 - 2].Unmarshall(p2);
+  disp_args[5 - 3].Unmarshall(p3);
+  disp_args[5 - 4].Unmarshall(p4);
+  disp_args[5 - 5].Unmarshall(p5);
+
+  // Unmarshall the return value.
+  if (result_out != NULL)
+    result.Unmarshall(result_out);
+
+  return S_OK;
+}
+
+template <typename P1, typename P2, typename P3, typename P4, typename P5,
+    typename P6>
+HRESULT Invoke(IDispatch* object,
+               LPOLESTR name,
+               WORD flags,
+               const P1& p1,
+               const P2& p2,
+               const P3& p3,
+               const P4& p4,
+               const P5& p5,
+               const P6& p6,
+               VARIANT* const & result_out) {
+  COMPILE_ASSERT(internal::is_param<P1>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P2>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P3>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P4>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P5>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P6>::value, parameters_must_be_variants);
+
+  // Retrieve the ID of the method to be called.
+  DISPID disp_id;
+  HRESULT hr = object->GetIDsOfNames(IID_NULL, &name, 1, LOCALE_USER_DEFAULT,
+                                     &disp_id);
+  if (FAILED(hr))
+    return hr;
+
+  // Request the return value if asked by the caller.
+  internal::ScopedVariantArg result;
+  VARIANT* disp_result = NULL;
+  if (result_out != NULL)
+    disp_result = &result;
+
+  // Marshal the parameters into an array of VARIANT structures.
+  internal::ScopedVariantArg disp_args[6];
+  hr = disp_args[6 - 1].Marshall(p1);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[6 - 2].Marshall(p2);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[6 - 3].Marshall(p3);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[6 - 4].Marshall(p4);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[6 - 5].Marshall(p5);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[6 - 6].Marshall(p6);
+  if (FAILED(hr))
+    return hr;
+
+  // Invoke the method.
+  DISPPARAMS disp_params = { disp_args, NULL, 6, 0 };
+  hr = object->Invoke(disp_id, IID_NULL, LOCALE_USER_DEFAULT, flags,
+                      &disp_params, disp_result, NULL, NULL);
+  if (FAILED(hr))
+    return hr;
+
+  // Unmarshall the parameters.
+  disp_args[6 - 1].Unmarshall(p1);
+  disp_args[6 - 2].Unmarshall(p2);
+  disp_args[6 - 3].Unmarshall(p3);
+  disp_args[6 - 4].Unmarshall(p4);
+  disp_args[6 - 5].Unmarshall(p5);
+  disp_args[6 - 6].Unmarshall(p6);
+
+  // Unmarshall the return value.
+  if (result_out != NULL)
+    result.Unmarshall(result_out);
+
+  return S_OK;
+}
+
+template <typename P1, typename P2, typename P3, typename P4, typename P5,
+    typename P6, typename P7>
+HRESULT Invoke(IDispatch* object,
+               LPOLESTR name,
+               WORD flags,
+               const P1& p1,
+               const P2& p2,
+               const P3& p3,
+               const P4& p4,
+               const P5& p5,
+               const P6& p6,
+               const P7& p7,
+               VARIANT* const & result_out) {
+  COMPILE_ASSERT(internal::is_param<P1>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P2>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P3>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P4>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P5>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P6>::value, parameters_must_be_variants);
+  COMPILE_ASSERT(internal::is_param<P7>::value, parameters_must_be_variants);
+
+  // Retrieve the ID of the method to be called.
+  DISPID disp_id;
+  HRESULT hr = object->GetIDsOfNames(IID_NULL, &name, 1, LOCALE_USER_DEFAULT,
+                                     &disp_id);
+  if (FAILED(hr))
+    return hr;
+
+  // Request the return value if asked by the caller.
+  internal::ScopedVariantArg result;
+  VARIANT* disp_result = NULL;
+  if (result_out != NULL)
+    disp_result = &result;
+
+  // Marshal the parameters into an array of VARIANT structures.
+  internal::ScopedVariantArg disp_args[7];
+  hr = disp_args[7 - 1].Marshall(p1);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[7 - 2].Marshall(p2);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[7 - 3].Marshall(p3);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[7 - 4].Marshall(p4);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[7 - 5].Marshall(p5);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[7 - 6].Marshall(p6);
+  if (FAILED(hr))
+    return hr;
+  hr = disp_args[7 - 7].Marshall(p7);
+  if (FAILED(hr))
+    return hr;
+
+  // Invoke the method.
+  DISPPARAMS disp_params = { disp_args, NULL, 7, 0 };
+  hr = object->Invoke(disp_id, IID_NULL, LOCALE_USER_DEFAULT, flags,
+                      &disp_params, disp_result, NULL, NULL);
+  if (FAILED(hr))
+    return hr;
+
+  // Unmarshall the parameters.
+  disp_args[7 - 1].Unmarshall(p1);
+  disp_args[7 - 2].Unmarshall(p2);
+  disp_args[7 - 3].Unmarshall(p3);
+  disp_args[7 - 4].Unmarshall(p4);
+  disp_args[7 - 5].Unmarshall(p5);
+  disp_args[7 - 6].Unmarshall(p6);
+  disp_args[7 - 7].Unmarshall(p7);
+
+  // Unmarshall the return value.
+  if (result_out != NULL)
+    result.Unmarshall(result_out);
+
+  return S_OK;
+}
+
+} // namespace dispatch
+
+} // namespace remoting
+
+#endif // REMOTING_BASE_IDISPATCH_DRIVER_WIN_H_