react-native/Libraries/Text/RCTShadowRawText.m
Alex Akers 3c5b4b0a9f [React Native] Remove layout-only nodes
Summary:
Remove layout-only views. Works by checking properties against a list of known properties that only affect layout. The `RCTShadowView` hierarchy still has a 1:1 correlation with the JS nodes.

This works by adjusting the tags and indices in `manageChildren`. For example, if JS told us to insert tag 1 at index 0 and tag 1 is layout-only with children whose tags are 2 and 3, we adjust it so we insert tags 2 and 3 at indices 0 and 1. This keeps changes out of `RCTView` and `RCTScrollView`. In order to simplify this logic, view moves are now processed as view removals followed by additions. A move from index 0 to 1 is recorded as a removal of view at indices 0 and 1 and an insertion of tags 1 and 2 at indices 0 and 1. Of course, the remaining indices have to be offset to take account for this.

The `collapsible` attribute is a bit of a hack to force `RCTScrollView` to always have one child. This was easier than rethinking out the logic there, but we could change this later.

@public

Test Plan: There are tests in `RCTUIManagerTests.m` that test the tag- and index-manipulation logic works. There are various scenarios including add-only, remove-only, and move. In addition, two scenario tests verify that the optimization works by checking the number of views and shadow views after various situations happen.
2015-06-25 09:12:00 -08:00

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Objective-C

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
#import "RCTShadowRawText.h"
@implementation RCTShadowRawText
- (void)setText:(NSString *)text
{
if (_text != text) {
_text = [text copy];
[self dirtyLayout];
[self dirtyText];
}
}
- (BOOL)isLayoutOnly
{
return YES;
}
- (NSString *)description
{
NSString *superDescription = super.description;
return [[superDescription substringToIndex:superDescription.length - 1] stringByAppendingFormat:@"; text: %@>", self.text];
}
@end