//

// ASViewController.mm

// AsyncDisplayKit

//

// Created by Huy Nguyen on 16/09/15.

//

// Copyright (c) 2014-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 "ASViewController.h"

#import "ASAssert.h"

#import "ASAvailability.h"

#import "ASDisplayNodeInternal.h"

#import "ASDisplayNode+FrameworkPrivate.h"

#import "ASLayout.h"

#import "ASTraitCollection.h"

#import "ASEnvironmentInternal.h"

#import "ASRangeControllerUpdateRangeProtocol+Beta.h"

#define AS_LOG_VISIBILITY_CHANGES 0

@implementation ASViewController

{

BOOL _ensureDisplayed;

BOOL _automaticallyAdjustRangeModeBasedOnViewEvents;

BOOL _parentManagesVisibilityDepth;

NSInteger _visibilityDepth;

BOOL _selfConformsToRangeModeProtocol;

BOOL _nodeConformsToRangeModeProtocol;

}

- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil

{

ASDisplayNodeAssert(NO, @"ASViewController requires using -initWithNode:");

return [self initWithNode:[[ASDisplayNode alloc] init]];

}

- (instancetype)initWithCoder:(NSCoder *)aDecoder

{

ASDisplayNodeAssert(NO, @"ASViewController requires using -initWithNode:");

return [self initWithNode:[[ASDisplayNode alloc] init]];

}

- (instancetype)initWithNode:(ASDisplayNode *)node

{

if (!(self = [super initWithNibName:nil bundle:nil])) {

return nil;

}

ASDisplayNodeAssertNotNil(node, @"Node must not be nil");

ASDisplayNodeAssertTrue(!node.layerBacked);

_node = node;

_selfConformsToRangeModeProtocol = [self conformsToProtocol:@protocol(ASRangeControllerUpdateRangeProtocol)];

_nodeConformsToRangeModeProtocol = [_node conformsToProtocol:@protocol(ASRangeControllerUpdateRangeProtocol)];

_automaticallyAdjustRangeModeBasedOnViewEvents = _selfConformsToRangeModeProtocol || _nodeConformsToRangeModeProtocol;

return self;

}

- (void)loadView

{

ASDisplayNodeAssertTrue(!_node.layerBacked);

// Apple applies a frame and autoresizing masks we need. Allocating a view is not

// nearly as expensive as adding and removing it from a hierarchy, and fortunately

// we can avoid that here. Enabling layerBacking on a single node in the hierarchy

// will have a greater performance benefit than the impact of this transient view.

[super loadView];

UIView *view = self.view;

CGRect frame = view.frame;

UIViewAutoresizing autoresizingMask = view.autoresizingMask;

// We have what we need, so now create and assign the view we actually want.

view = _node.view;

_node.frame = frame;

_node.autoresizingMask = autoresizingMask;

self.view = view;

// ensure that self.node has a valid trait collection before a subclass's implementation of viewDidLoad.

// Any subnodes added in viewDidLoad will then inherit the proper environment.

if (AS_AT_LEAST_IOS8) {

ASEnvironmentTraitCollection traitCollection = [self environmentTraitCollectionForUITraitCollection:self.traitCollection];

[self progagateNewEnvironmentTraitCollection:traitCollection];

} else {

ASEnvironmentTraitCollection traitCollection = ASEnvironmentTraitCollectionMakeDefault();

traitCollection.containerSize = self.view.bounds.size;

[self progagateNewEnvironmentTraitCollection:traitCollection];

}

}

- (void)viewWillLayoutSubviews

{

[super viewWillLayoutSubviews];

// Before layout, make sure that our trait collection containerSize actually matches the size of our bounds.

// If not, we need to update the traits and propagate them.

if (CGSizeEqualToSize(self.node.environmentTraitCollection.containerSize, self.view.bounds.size) == NO) {

[UIView performWithoutAnimation:^{

ASEnvironmentTraitCollection environmentTraitCollection;

if (AS_AT_LEAST_IOS8) {

environmentTraitCollection = [self environmentTraitCollectionForUITraitCollection:self.traitCollection];

} else {

environmentTraitCollection = ASEnvironmentTraitCollectionMakeDefault();

}

environmentTraitCollection.containerSize = self.view.bounds.size;

// this method will call measure

[self progagateNewEnvironmentTraitCollection:environmentTraitCollection];

}];

} else {

[_node layoutThatFits:[self nodeConstrainedSize]];

}

if (!AS_AT_LEAST_IOS9) {

[self _legacyHandleViewDidLayoutSubviews];

}

}

- (void)viewDidLayoutSubviews

{

if (_ensureDisplayed && self.neverShowPlaceholders) {

_ensureDisplayed = NO;

[self.node recursivelyEnsureDisplaySynchronously:YES];

}

[super viewDidLayoutSubviews];

}

ASVisibilityDidMoveToParentViewController;

- (void)viewWillAppear:(BOOL)animated

{

[super viewWillAppear:animated];

_ensureDisplayed = YES;

// We do this early layout because we need to get any ASCollectionNodes etc. into the

// hierarchy before UIKit applies the scroll view inset adjustments, if you are using

// automatic subnode management.

[_node layoutThatFits:[self nodeConstrainedSize]];

[_node recursivelyFetchData];

if (_parentManagesVisibilityDepth == NO) {

[self setVisibilityDepth:0];

}

}

ASVisibilitySetVisibilityDepth;

ASVisibilityViewDidDisappearImplementation;

ASVisibilityDepthImplementation;

- (void)visibilityDepthDidChange

{

ASLayoutRangeMode rangeMode = ASLayoutRangeModeForVisibilityDepth(self.visibilityDepth);

#if AS_LOG_VISIBILITY_CHANGES

NSString *rangeModeString;

switch (rangeMode) {

case ASLayoutRangeModeMinimum:

rangeModeString = @"Minimum";

break;

case ASLayoutRangeModeFull:

rangeModeString = @"Full";

break;

case ASLayoutRangeModeVisibleOnly:

rangeModeString = @"Visible Only";

break;

case ASLayoutRangeModeLowMemory:

rangeModeString = @"Low Memory";

break;

default:

break;

}

NSLog(@"Updating visibility of:%@ to: %@ (visibility depth: %d)", self, rangeModeString, self.visibilityDepth);

#endif

[self updateCurrentRangeModeWithModeIfPossible:rangeMode];

}

#pragma mark - Automatic range mode

- (BOOL)automaticallyAdjustRangeModeBasedOnViewEvents

{

return _automaticallyAdjustRangeModeBasedOnViewEvents;

}

- (void)setAutomaticallyAdjustRangeModeBasedOnViewEvents:(BOOL)automaticallyAdjustRangeModeBasedOnViewEvents

{

if (automaticallyAdjustRangeModeBasedOnViewEvents != _automaticallyAdjustRangeModeBasedOnViewEvents) {

if (automaticallyAdjustRangeModeBasedOnViewEvents && _selfConformsToRangeModeProtocol == NO && _nodeConformsToRangeModeProtocol == NO) {

NSLog(@"Warning: automaticallyAdjustRangeModeBasedOnViewEvents set to YES in %@, but range mode updating is not possible because neither view controller nor node %@ conform to ASRangeControllerUpdateRangeProtocol.", self, _node);

}

_automaticallyAdjustRangeModeBasedOnViewEvents = automaticallyAdjustRangeModeBasedOnViewEvents;

}

}

- (void)updateCurrentRangeModeWithModeIfPossible:(ASLayoutRangeMode)rangeMode

{

if (!_automaticallyAdjustRangeModeBasedOnViewEvents) { return; }

if (_selfConformsToRangeModeProtocol) {

id<ASRangeControllerUpdateRangeProtocol> rangeUpdater = (id<ASRangeControllerUpdateRangeProtocol>)self;

[rangeUpdater updateCurrentRangeWithMode:rangeMode];

}

if (_nodeConformsToRangeModeProtocol) {

id<ASRangeControllerUpdateRangeProtocol> rangeUpdater = (id<ASRangeControllerUpdateRangeProtocol>)_node;

[rangeUpdater updateCurrentRangeWithMode:rangeMode];

}

}

#pragma mark - Layout Helpers

- (ASSizeRange)nodeConstrainedSize

{

if (AS_AT_LEAST_IOS9) {

CGSize viewSize = self.view.bounds.size;

return ASSizeRangeMake(viewSize, viewSize);

} else {

return [self _legacyConstrainedSize];

}

}

- (ASInterfaceState)interfaceState

{

return _node.interfaceState;

}

#pragma mark - Legacy Layout Handling

- (BOOL)_shouldLayoutTheLegacyWay

{

BOOL isModalViewController = (self.presentingViewController != nil && self.presentedViewController == nil);

BOOL hasNavigationController = (self.navigationController != nil);

BOOL hasParentViewController = (self.parentViewController != nil);

if (isModalViewController && !hasNavigationController && !hasParentViewController) {

return YES;

}

// Check if the view controller is a root view controller

BOOL isRootViewController = self.view.window.rootViewController == self;

if (isRootViewController) {

return YES;

}

return NO;

}

- (ASSizeRange)_legacyConstrainedSize

{

// In modal presentation the view does not have the right bounds in iOS7 and iOS8. As workaround using the superviews

// view bounds

UIView *view = self.view;

CGSize viewSize = view.bounds.size;

if ([self _shouldLayoutTheLegacyWay]) {

UIView *superview = view.superview;

if (superview != nil) {

viewSize = superview.bounds.size;

}

}

return ASSizeRangeMake(viewSize, viewSize);

}

- (void)_legacyHandleViewDidLayoutSubviews

{

// In modal presentation or as root viw controller the view does not automatic resize in iOS7 and iOS8.

// As workaround we adjust the frame of the view manually

if ([self _shouldLayoutTheLegacyWay]) {

CGSize maxConstrainedSize = [self nodeConstrainedSize].max;

_node.frame = (CGRect){.origin = CGPointZero, .size = maxConstrainedSize};

}

}

#pragma mark - ASEnvironmentTraitCollection

- (ASEnvironmentTraitCollection)environmentTraitCollectionForUITraitCollection:(UITraitCollection *)traitCollection

{

if (self.overrideDisplayTraitsWithTraitCollection) {

ASTraitCollection *asyncTraitCollection = self.overrideDisplayTraitsWithTraitCollection(traitCollection);

return [asyncTraitCollection environmentTraitCollection];

}

ASDisplayNodeAssertMainThread();

ASEnvironmentTraitCollection asyncTraitCollection = ASEnvironmentTraitCollectionFromUITraitCollection(traitCollection);

asyncTraitCollection.containerSize = self.view.frame.size;

return asyncTraitCollection;

}

- (void)progagateNewEnvironmentTraitCollection:(ASEnvironmentTraitCollection)environmentTraitCollection

{

ASEnvironmentState environmentState = self.node.environmentState;

ASEnvironmentTraitCollection oldEnvironmentTraitCollection = environmentState.environmentTraitCollection;

if (ASEnvironmentTraitCollectionIsEqualToASEnvironmentTraitCollection(environmentTraitCollection, oldEnvironmentTraitCollection) == NO) {

environmentState.environmentTraitCollection = environmentTraitCollection;

self.node.environmentState = environmentState;

NSArray<id<ASEnvironment>> *children = [self.node children];

for (id<ASEnvironment> child in children) {

ASEnvironmentStatePropagateDown(child, environmentState.environmentTraitCollection);

}

// once we've propagated all the traits, layout this node.

// Remeasure the node with the latest constrained size – old constrained size may be incorrect.

[self.node layoutThatFits:[self nodeConstrainedSize]];

}

}

- (void)traitCollectionDidChange:(UITraitCollection *)previousTraitCollection

{

[super traitCollectionDidChange:previousTraitCollection];

ASEnvironmentTraitCollection environmentTraitCollection = [self environmentTraitCollectionForUITraitCollection:self.traitCollection];

environmentTraitCollection.containerSize = self.view.bounds.size;

[self progagateNewEnvironmentTraitCollection:environmentTraitCollection];

}

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation

{

[super didRotateFromInterfaceOrientation:fromInterfaceOrientation];

ASEnvironmentTraitCollection traitCollection = self.node.environmentTraitCollection;

traitCollection.containerSize = self.view.bounds.size;

[self progagateNewEnvironmentTraitCollection:traitCollection];

}

@end