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33 lines
1.4 KiB
C++
33 lines
1.4 KiB
C++
// Copyright 2013 The Flutter Authors. All rights reserved.
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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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#ifndef FLUTTER_SHELL_PLATFORM_EMBEDDER_EMBEDDER_SAFE_ACCESS_H_
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#define FLUTTER_SHELL_PLATFORM_EMBEDDER_EMBEDDER_SAFE_ACCESS_H_
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#include <type_traits>
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// Checks if the given struct contains a member, whether set or not.
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#define STRUCT_HAS_MEMBER(pointer, member) \
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((offsetof(std::remove_pointer<decltype(pointer)>::type, member) + \
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sizeof(pointer->member) <= \
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pointer->struct_size))
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#define SAFE_ACCESS(pointer, member, default_value) \
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([=]() { \
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if (STRUCT_HAS_MEMBER(pointer, member)) { \
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return pointer->member; \
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} \
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return static_cast<decltype(pointer->member)>((default_value)); \
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})()
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/// Checks if the member exists and is non-null.
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#define SAFE_EXISTS(pointer, member) \
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(SAFE_ACCESS(pointer, member, nullptr) != nullptr)
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/// Checks if exactly one of member1 or member2 exists and is non-null.
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#define SAFE_EXISTS_ONE_OF(pointer, member1, member2) \
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(SAFE_EXISTS(pointer, member1) != SAFE_EXISTS(pointer, member2))
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#endif // FLUTTER_SHELL_PLATFORM_EMBEDDER_EMBEDDER_SAFE_ACCESS_H_
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