82 lines
2.3 KiB
C++
82 lines
2.3 KiB
C++
// Copyright 2011 The Chromium Authors
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/win/enum_variant.h"
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#include <wrl/client.h>
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#include <algorithm>
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#include "base/check_op.h"
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namespace base {
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namespace win {
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EnumVariant::EnumVariant(ULONG count) : current_index_(0) {
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for (ULONG i = 0; i < count; ++i)
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items_.emplace_back(ScopedVariant::kEmptyVariant);
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}
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EnumVariant::~EnumVariant() = default;
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VARIANT* EnumVariant::ItemAt(ULONG index) {
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DCHECK_LT(index, items_.size());
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// This is a hack to return a mutable pointer to the ScopedVariant, even
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// though the original intent of the AsInput method was to allow only readonly
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// access to the wrapped variant.
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return items_[index].AsInput();
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}
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HRESULT EnumVariant::Next(ULONG requested_count,
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VARIANT* out_elements,
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ULONG* out_elements_received) {
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if (!out_elements)
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return E_INVALIDARG;
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DCHECK_LE(current_index_, items_.size());
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ULONG available_count = static_cast<ULONG>(items_.size()) - current_index_;
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ULONG count = std::min(requested_count, available_count);
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for (ULONG i = 0; i < count; ++i)
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out_elements[i] = items_[current_index_ + i].Copy();
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current_index_ += count;
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// The caller can choose not to get the number of received elements by setting
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// |out_elements_received| to nullptr.
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if (out_elements_received)
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*out_elements_received = count;
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return (count == requested_count ? S_OK : S_FALSE);
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}
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HRESULT EnumVariant::Skip(ULONG skip_count) {
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ULONG count = skip_count;
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if (current_index_ + count > static_cast<ULONG>(items_.size()))
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count = static_cast<ULONG>(items_.size()) - current_index_;
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current_index_ += count;
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return (count == skip_count ? S_OK : S_FALSE);
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}
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HRESULT EnumVariant::Reset() {
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current_index_ = 0;
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return S_OK;
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}
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HRESULT EnumVariant::Clone(IEnumVARIANT** out_cloned_object) {
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if (!out_cloned_object)
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return E_INVALIDARG;
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size_t count = items_.size();
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Microsoft::WRL::ComPtr<EnumVariant> other =
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Microsoft::WRL::Make<EnumVariant>(static_cast<ULONG>(count));
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for (size_t i = 0; i < count; ++i)
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other->items_[i] = static_cast<const VARIANT&>(items_[i]);
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other->Skip(current_index_);
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return other.CopyTo(IID_PPV_ARGS(out_cloned_object));
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}
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} // namespace win
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} // namespace base
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