text: //
  //  ASLayoutElementPrivate.h
  //  AsyncDisplayKit
  //
  //  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 <AsyncDisplayKit/ASDimension.h>
  #import <UIKit/UIGeometry.h>
  
  @protocol ASLayoutElement;
  @class ASLayoutElementStyle;
  
  #pragma mark - ASLayoutElementContext
  
  struct ASLayoutElementContext {
    int32_t transitionID;
  };
  
  extern int32_t const ASLayoutElementContextInvalidTransitionID;
  
  extern int32_t const ASLayoutElementContextDefaultTransitionID;
  
  extern struct ASLayoutElementContext const ASLayoutElementContextNull;
  
  extern BOOL ASLayoutElementContextIsNull(struct ASLayoutElementContext context);
  
  extern struct ASLayoutElementContext ASLayoutElementContextMake(int32_t transitionID);
  
  extern void ASLayoutElementSetCurrentContext(struct ASLayoutElementContext context);
  
  extern struct ASLayoutElementContext ASLayoutElementGetCurrentContext();
  
  extern void ASLayoutElementClearCurrentContext();
  
  
  #pragma mark - ASLayoutElementLayoutDefaults
  
  #define ASLayoutElementLayoutCalculationDefaults \
  - (ASLayout *)layoutThatFits:(ASSizeRange)constrainedSize\
  {\
    _Pragma("clang diagnostic push")\
    _Pragma("clang diagnostic ignored \"-Wdeprecated-declarations\"")\
    /* For now we just call the deprecated measureWithSizeRange: method to not break old API */ \
    return [self measureWithSizeRange:constrainedSize]; \
    _Pragma("clang diagnostic pop")\
  } \
  \
  - (ASLayout *)measureWithSizeRange:(ASSizeRange)constrainedSize\
  {\
    return [self layoutThatFits:constrainedSize parentSize:constrainedSize.max];\
  }\
  \
  - (ASLayout *)calculateLayoutThatFits:(ASSizeRange)constrainedSize\
                       restrictedToSize:(ASLayoutElementSize)size\
                   relativeToParentSize:(CGSize)parentSize\
  {\
    const ASSizeRange resolvedRange = ASSizeRangeIntersect(constrainedSize, ASLayoutElementSizeResolve(self.style.size, parentSize));\
    return [self calculateLayoutThatFits:resolvedRange];\
  }\
  
  
  #pragma mark - ASLayoutElementFinalLayoutElement
  /**
   *  The base protocol for ASLayoutElementFinalLayoutElement. Generally the methods/properties in this class do not need to be
   *  called by the end user and are only called internally. However, there may be a case where the methods are useful.
   */
  @protocol ASLayoutElementFinalLayoutElement <NSObject>
  
  /**
   *  @abstract This method can be used to give the user a chance to wrap an ASLayoutElement in an ASLayoutSpec 
   *  just before it is added to a parent ASLayoutSpec. For example, if you wanted an ASTextNode that was always 
   *  inside of an ASInsetLayoutSpec, you could subclass ASTextNode and implement finalLayoutElement so that it wraps
   *  itself in an inset spec.
   *
   *  Note that any ASLayoutElement other than self that is returned MUST set isFinalLayoutElement to YES. Make sure
   *  to do this BEFORE adding a child to the ASLayoutElement.
   *
   *  @return The layoutElement that will be added to the parent layout spec. Defaults to self.
   */
  - (id<ASLayoutElement>)finalLayoutElement;
  
  /**
   *  A flag to indicate that this ASLayoutElement was created in finalLayoutElement. This MUST be set to YES
   *  before adding a child to this layoutElement.
   */
  @property (nonatomic, assign) BOOL isFinalLayoutElement;
  
  @end
  
  // Default implementation for ASLayoutElementPrivate that can be used in classes that comply to ASLayoutElementPrivate
  
  #define ASLayoutElementFinalLayoutElementDefault \
  \
  @synthesize isFinalLayoutElement = _isFinalLayoutElement;\
  \
  - (id<ASLayoutElement>)finalLayoutElement\
  {\
      return self;\
  }\
  
  
  #pragma mark - ASLayoutElementExtensibility
  
  // Provides extension points for elments that comply to ASLayoutElement like ASLayoutSpec to add additional
  // properties besides the default one provided in ASLayoutElementStyle
  
  static const int kMaxLayoutElementBoolExtensions = 1;
  static const int kMaxLayoutElementStateIntegerExtensions = 4;
  static const int kMaxLayoutElementStateEdgeInsetExtensions = 1;
  
  typedef struct ASLayoutElementStyleExtensions {
    // Values to store extensions
    BOOL boolExtensions[kMaxLayoutElementBoolExtensions];
    NSInteger integerExtensions[kMaxLayoutElementStateIntegerExtensions];
    UIEdgeInsets edgeInsetsExtensions[kMaxLayoutElementStateEdgeInsetExtensions];
  } ASLayoutElementStyleExtensions;
  
  #define ASLayoutElementStyleExtensibilityForwarding \
  - (void)setLayoutOptionExtensionBool:(BOOL)value atIndex:(int)idx\
  {\
    [self.style setLayoutOptionExtensionBool:value atIndex:idx];\
  }\
  \
  - (BOOL)layoutOptionExtensionBoolAtIndex:(int)idx\
  {\
    return [self.style layoutOptionExtensionBoolAtIndex:idx];\
  }\
  \
  - (void)setLayoutOptionExtensionInteger:(NSInteger)value atIndex:(int)idx\
  {\
    [self.style setLayoutOptionExtensionInteger:value atIndex:idx];\
  }\
  \
  - (NSInteger)layoutOptionExtensionIntegerAtIndex:(int)idx\
  {\
    return [self.style layoutOptionExtensionIntegerAtIndex:idx];\
  }\
  \
  - (void)setLayoutOptionExtensionEdgeInsets:(UIEdgeInsets)value atIndex:(int)idx\
  {\
    [self.style setLayoutOptionExtensionEdgeInsets:value atIndex:idx];\
  }\
  \
  - (UIEdgeInsets)layoutOptionExtensionEdgeInsetsAtIndex:(int)idx\
  {\
    return [self.style layoutOptionExtensionEdgeInsetsAtIndex:idx];\
  }\
  
  #pragma mark ASLayoutElementStyleForwardingDeclaration (Deprecated)
  
  #define ASLayoutElementStyleForwardingDeclaration \
  @property (nonatomic, readwrite) CGFloat spacingBefore ASDISPLAYNODE_DEPRECATED_MSG("Use style.spacingBefore"); \
  @property (nonatomic, readwrite) CGFloat spacingAfter ASDISPLAYNODE_DEPRECATED_MSG("Use style.spacingAfter"); \
  @property (nonatomic, readwrite) CGFloat flexGrow ASDISPLAYNODE_DEPRECATED_MSG("Use style.flexGrow"); \
  @property (nonatomic, readwrite) CGFloat flexShrink ASDISPLAYNODE_DEPRECATED_MSG("Use style.flexShrink"); \
  @property (nonatomic, readwrite) ASDimension flexBasis ASDISPLAYNODE_DEPRECATED_MSG("Use style.flexBasis"); \
  @property (nonatomic, readwrite) ASStackLayoutAlignSelf alignSelf ASDISPLAYNODE_DEPRECATED_MSG("Use style.alignSelf"); \
  @property (nonatomic, readwrite) CGFloat ascender ASDISPLAYNODE_DEPRECATED_MSG("Use style.ascender"); \
  @property (nonatomic, readwrite) CGFloat descender ASDISPLAYNODE_DEPRECATED_MSG("Use style.descender"); \
  @property (nonatomic, assign) ASRelativeSizeRange sizeRange ASDISPLAYNODE_DEPRECATED_MSG("Don't use sizeRange anymore instead set style.width or style.height"); \
  @property (nonatomic, assign) CGPoint layoutPosition ASDISPLAYNODE_DEPRECATED_MSG("Use style.layoutPosition"); \
  
  
  #pragma mark - ASLayoutElementStyleForwarding (Deprecated)
  
  // For the time beeing we are forwading all style related properties on ASDisplayNode and ASLayoutSpec. This define
  // help us to not have duplicate code while moving from 1.x to 2.0s
  #define ASLayoutElementStyleForwarding \
  \
  @dynamic spacingBefore, spacingAfter, flexGrow, flexShrink, flexBasis, alignSelf, ascender, descender, sizeRange, layoutPosition;\
  \
  _Pragma("mark - ASStackLayoutElement")\
  \
  - (void)setSpacingBefore:(CGFloat)spacingBefore\
  {\
    self.style.spacingBefore = spacingBefore;\
  }\
  \
  - (CGFloat)spacingBefore\
  {\
    return self.style.spacingBefore;\
  }\
  \
  - (void)setSpacingAfter:(CGFloat)spacingAfter\
  {\
    self.style.spacingAfter = spacingAfter;\
  }\
  \
  - (CGFloat)spacingAfter\
  {\
    return self.style.spacingAfter;\
  }\
  \
  - (void)setFlexGrow:(CGFloat)flexGrow\
  {\
    self.style.flexGrow = flexGrow;\
  }\
  \
  - (CGFloat)flexGrow\
  {\
    return self.style.flexGrow;\
  }\
  \
  - (void)setFlexShrink:(CGFloat)flexShrink\
  {\
    self.style.flexShrink = flexShrink;\
  }\
  \
  - (CGFloat)flexShrink\
  {\
    return self.style.flexShrink;\
  }\
  \
  - (void)setFlexBasis:(ASDimension)flexBasis\
  {\
    self.style.flexBasis = flexBasis;\
  }\
  \
  - (ASDimension)flexBasis\
  {\
    return self.style.flexBasis;\
  }\
  \
  - (void)setAlignSelf:(ASStackLayoutAlignSelf)alignSelf\
  {\
    self.style.alignSelf = alignSelf;\
  }\
  \
  - (ASStackLayoutAlignSelf)alignSelf\
  {\
    return self.style.alignSelf;\
  }\
  \
  - (void)setAscender:(CGFloat)ascender\
  {\
    self.style.ascender = ascender;\
  }\
  \
  - (CGFloat)ascender\
  {\
    return self.style.ascender;\
  }\
  \
  - (void)setDescender:(CGFloat)descender\
  {\
    self.style.descender = descender;\
  }\
  \
  - (CGFloat)descender\
  {\
    return self.style.descender;\
  }\
  \
  _Pragma("mark - ASAbsoluteLayoutElement")\
  \
  - (void)setLayoutPosition:(CGPoint)layoutPosition\
  {\
    self.style.layoutPosition = layoutPosition;\
  }\
  \
  - (CGPoint)layoutPosition\
  {\
    return self.style.layoutPosition;\
  }\
  \
  _Pragma("clang diagnostic push")\
  _Pragma("clang diagnostic ignored \"-Wdeprecated-declarations\"")\
  \
  - (void)setSizeRange:(ASRelativeSizeRange)sizeRange\
  {\
    self.style.sizeRange = sizeRange;\
  }\
  \
  - (ASRelativeSizeRange)sizeRange\
  {\
    return self.style.sizeRange;\
  }\
  \
  _Pragma("clang diagnostic pop")\
  