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https://github.com/zhigang1992/react-native.git
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a0523da53d
Summary: Apparently we can/should not have in RCTConversions because it creates unnecessary dependency to core iOS module. Reviewed By: mdvacca Differential Revision: D15055325 fbshipit-source-id: 507f5a40c03b5c261967de4504297d31ecd02783
45 lines
1.4 KiB
C++
45 lines
1.4 KiB
C++
/**
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#pragma once
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#ifdef __OBJC__
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#ifdef __cplusplus
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#include <memory>
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namespace facebook {
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namespace react {
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/*
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* `wrapManagedObject` and `unwrapManagedObject` are wrapper functions that
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* convert ARC-managed objects into `std::shared_ptr<void>` and vice-versa. It's
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* a very useful mechanism when we need to pass Objective-C objects through pure
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* C++ code, pass blocks into C++ lambdas, and so on.
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*
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* The idea behind this mechanism is quite simple but tricky: When we
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* instantiate a C++ shared pointer for a managed object, we practically call
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* `CFRetain` for it once and then we represent this single retaining operation
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* as a counter inside the shared pointer; when the counter became zero, we call
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* `CFRelease` on the object. In this model, one bump of ARC-managed counter is
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* represented as multiple bumps of C++ counter, so we can have multiple
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* counters for the same object that form some kind of counters tree.
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*/
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inline std::shared_ptr<void> wrapManagedObject(id object) {
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return std::shared_ptr<void>((__bridge_retained void *)object, CFRelease);
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}
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inline id unwrapManagedObject(std::shared_ptr<void> const &object) {
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return (__bridge id)object.get();
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}
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} // namespace react
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} // namespace facebook
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#endif
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#endif
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