Introduce let / var macros and some further cleanup (#1012)

* Introduce let / var and some further cleanup

* Address first comments

* Update changelog

* Move the const before auto

CHANGELOG.md

@@ -74,6 +74,7 @@
 - Add an experimental deallocation queue implementation that's more efficient. [Adlai Holler](https://github.com/Adlai-Holler)
 - Standardize property declaration style. [Adlai Holler](https://github.com/Adlai-Holler)
 - [ASTableView] Fix an issue that causes table view to use one of a cell's invalid layouts instead of generating a new one. [Huy Nguyen](https://github.com/nguyenhuy) [#942](https://github.com/TextureGroup/Texture/pull/942)
+- Introduce let / var macros and some further cleanup. [Michael Schneider](https://github.com/maicki) [#1012](https://github.com/TextureGroup/Texture/pull/1012)
 
 ## 2.6
 - [Xcode 9] Updated to require Xcode 9 (to fix warnings) [Garrett Moon](https://github.com/garrettmoon)

Source/ASCollectionView.mm

@@ -1545,7 +1545,7 @@ - (BOOL)collectionView:(UICollectionView *)collectionView canMoveItemAtIndexPath
 
   // If the data source implements canMoveItem, let them decide.
   if (_asyncDataSourceFlags.collectionNodeCanMoveItem) {
-    if (auto cellNode = [self nodeForItemAtIndexPath:indexPath]) {
+    if (let cellNode = [self nodeForItemAtIndexPath:indexPath]) {
       GET_COLLECTIONNODE_OR_RETURN(collectionNode, NO);
       return [_asyncDataSource collectionNode:collectionNode canMoveItemWithNode:cellNode];
     }
@@ -1561,7 +1561,7 @@ - (void)collectionView:(UICollectionView *)collectionView moveItemAtIndexPath:(N
 
   // Inform the data source first, in case they call nodeForItemAtIndexPath:.
   // We want to make sure we return them the node for the item they have in mind.
-  if (auto collectionNode = self.collectionNode) {
+  if (let collectionNode = self.collectionNode) {
     [_asyncDataSource collectionNode:collectionNode moveItemAtIndexPath:sourceIndexPath toIndexPath:destinationIndexPath];
   }
 
@@ -1996,7 +1996,7 @@ - (ASCellNodeBlock)dataController:(ASDataController *)dataController supplementa
 - (NSArray<NSString *> *)dataController:(ASDataController *)dataController supplementaryNodeKindsInSections:(NSIndexSet *)sections
 {
   if (_asyncDataSourceFlags.collectionNodeSupplementaryElementKindsInSection) {
-    auto kinds = [[NSMutableSet<NSString *> alloc] init];
+    let kinds = [[NSMutableSet<NSString *> alloc] init];
     GET_COLLECTIONNODE_OR_RETURN(collectionNode, @[]);
     [sections enumerateIndexesUsingBlock:^(NSUInteger section, BOOL * _Nonnull stop) {
       NSArray<NSString *> *kindsForSection = [_asyncDataSource collectionNode:collectionNode supplementaryElementKindsInSection:section];
@@ -2214,7 +2214,7 @@ - (void)nodesDidRelayout:(NSArray<ASCellNode *> *)nodes
     return;
   }
 
-  auto uikitIndexPaths = ASArrayByFlatMapping(nodes, ASCellNode *node, [self indexPathForNode:node]);
+  let uikitIndexPaths = ASArrayByFlatMapping(nodes, ASCellNode *node, [self indexPathForNode:node]);
 
   [_layoutFacilitator collectionViewWillEditCellsAtIndexPaths:uikitIndexPaths batched:NO];
 

Source/ASDisplayNode+Layout.mm

@@ -646,8 +646,8 @@ - (void)transitionLayoutWithSizeRange:(ASSizeRange)constrainedSize
         ASDN::MutexLocker l(__instanceLock__);
 
         // Update calculated layout
-        auto previousLayout = _calculatedDisplayNodeLayout;
-        auto pendingLayout = std::make_shared<ASDisplayNodeLayout>(newLayout,
+        let previousLayout = _calculatedDisplayNodeLayout;
+        let pendingLayout = std::make_shared<ASDisplayNodeLayout>(newLayout,
                                                                    constrainedSize,
                                                                    constrainedSize.max,
                                                                    newLayoutVersion);
@@ -767,10 +767,10 @@ - (void)animateLayoutTransition:(id<ASContextTransitioning>)context
 
   NSArray<ASDisplayNode *> *removedSubnodes = [context removedSubnodes];
   NSMutableArray<ASDisplayNode *> *insertedSubnodes = [[context insertedSubnodes] mutableCopy];
-  auto movedSubnodes = [[NSMutableArray<ASDisplayNode *> alloc] init];
+  let movedSubnodes = [[NSMutableArray<ASDisplayNode *> alloc] init];
 
-  auto insertedSubnodeContexts = [[NSMutableArray<_ASAnimatedTransitionContext *> alloc] init];
-  auto removedSubnodeContexts = [[NSMutableArray<_ASAnimatedTransitionContext *> alloc] init];
+  let insertedSubnodeContexts = [[NSMutableArray<_ASAnimatedTransitionContext *> alloc] init];
+  let removedSubnodeContexts = [[NSMutableArray<_ASAnimatedTransitionContext *> alloc] init];
 
   for (ASDisplayNode *subnode in [context subnodesForKey:ASTransitionContextToLayoutKey]) {
     if ([insertedSubnodes containsObject:subnode] == NO) {
@@ -905,9 +905,9 @@ - (void)_assertSubnodeState
   NSArray *subnodes = [self subnodes];
   NSArray *sublayouts = _calculatedDisplayNodeLayout->layout.sublayouts;
 
-  auto currentSubnodes = [[NSHashTable alloc] initWithOptions:NSHashTableObjectPointerPersonality
+  let currentSubnodes = [[NSHashTable alloc] initWithOptions:NSHashTableObjectPointerPersonality
                                                      capacity:subnodes.count];
-  auto layoutSubnodes  = [[NSHashTable alloc] initWithOptions:NSHashTableObjectPointerPersonality
+  let layoutSubnodes  = [[NSHashTable alloc] initWithOptions:NSHashTableObjectPointerPersonality
                                                      capacity:sublayouts.count];;
   for (ASDisplayNode *subnode in subnodes) {
     [currentSubnodes addObject:subnode];

Source/ASDisplayNode.mm

@@ -3674,7 +3674,7 @@ - (NSString *)description
 - (NSString *)debugDescription
 {
   ASPushMainThreadAssertionsDisabled();
-  auto result = ASObjectDescriptionMake(self, [self propertiesForDebugDescription]);
+  let result = ASObjectDescriptionMake(self, [self propertiesForDebugDescription]);
   ASPopMainThreadAssertionsDisabled();
   return result;
 }
@@ -3746,7 +3746,7 @@ - (NSString *)detailedLayoutDescription
 {
   ASPushMainThreadAssertionsDisabled();
   ASDN::MutexLocker l(__instanceLock__);
-  auto props = [NSMutableArray<NSDictionary *> array];
+  let props = [[NSMutableArray<NSDictionary *> alloc] init];
 
   [props addObject:@{ @"layoutVersion": @(_layoutVersion.load()) }];
   [props addObject:@{ @"bounds": [NSValue valueWithCGRect:self.bounds] }];

Source/ASImageNode.mm

@@ -225,7 +225,7 @@ - (UIImage *)placeholderImage
 
 - (CGSize)calculateSizeThatFits:(CGSize)constrainedSize
 {
-  auto image = ASLockedSelf(_image);
+  let image = ASLockedSelf(_image);
 
   if (image == nil) {
     return [super calculateSizeThatFits:constrainedSize];

Source/ASMainThreadDeallocation.mm

@@ -146,7 +146,7 @@ @implementation NSObject (ASNeedsMainThreadDeallocation)
 
 + (BOOL)needsMainThreadDeallocation
 {
-  auto name = class_getName(self);
+  let name = class_getName(self);
   if (0 == strncmp(name, "AV", 2) || 0 == strncmp(name, "UI", 2) || 0 == strncmp(name, "CA", 2)) {
     return YES;
   }

Source/ASNetworkImageNode.mm

@@ -351,7 +351,7 @@ - (void)displayWillStartAsynchronously:(BOOL)asynchronously
         // Call out to the delegate.
         if (_delegateFlags.delegateDidLoadImageWithInfo) {
           ASUnlockScope(self);
-          auto info = [[ASNetworkImageLoadInfo alloc] initWithURL:url sourceType:ASNetworkImageSourceSynchronousCache downloadIdentifier:nil userInfo:nil];
+          let info = [[ASNetworkImageLoadInfo alloc] initWithURL:url sourceType:ASNetworkImageSourceSynchronousCache downloadIdentifier:nil userInfo:nil];
           [_delegate imageNode:self didLoadImage:result info:info];
         } else if (_delegateFlags.delegateDidLoadImage) {
           ASUnlockScope(self);
@@ -629,7 +629,7 @@ - (void)_lazilyLoadImageIfNecessary
         } else {
           // First try to load the path directly, for efficiency assuming a developer who
           // doesn't want caching is trying to be as minimal as possible.
-          auto nonAnimatedImage = [[UIImage alloc] initWithContentsOfFile:URL.path];
+          var nonAnimatedImage = [[UIImage alloc] initWithContentsOfFile:URL.path];
           if (nonAnimatedImage == nil) {
             // If we couldn't find it, execute an -imageNamed:-like search so we can find resources even if the
             // extension is not provided in the path.  This allows the same path to work regardless of shouldCacheImage.
@@ -642,7 +642,7 @@ - (void)_lazilyLoadImageIfNecessary
           // If the file may be an animated gif and then created an animated image.
           id<ASAnimatedImageProtocol> animatedImage = nil;
           if (_downloaderFlags.downloaderImplementsAnimatedImage) {
-            auto data = [[NSData alloc] initWithContentsOfURL:URL];
+            let data = [[NSData alloc] initWithContentsOfURL:URL];
             if (data != nil) {
               animatedImage = [_downloader animatedImageWithData:data];
 
@@ -665,7 +665,7 @@ - (void)_lazilyLoadImageIfNecessary
 
         if (_delegateFlags.delegateDidLoadImageWithInfo) {
           ASUnlockScope(self);
-          auto info = [[ASNetworkImageLoadInfo alloc] initWithURL:URL sourceType:ASNetworkImageSourceFileURL downloadIdentifier:nil userInfo:nil];
+          let info = [[ASNetworkImageLoadInfo alloc] initWithURL:URL sourceType:ASNetworkImageSourceFileURL downloadIdentifier:nil userInfo:nil];
           [delegate imageNode:self didLoadImage:self.image info:info];
         } else if (_delegateFlags.delegateDidLoadImage) {
           ASUnlockScope(self);
@@ -674,7 +674,7 @@ - (void)_lazilyLoadImageIfNecessary
       });
     } else {
       __weak __typeof__(self) weakSelf = self;
-      auto finished = ^(id <ASImageContainerProtocol>imageContainer, NSError *error, id downloadIdentifier, ASNetworkImageSourceType imageSource, id userInfo) {
+      let finished = ^(id <ASImageContainerProtocol>imageContainer, NSError *error, id downloadIdentifier, ASNetworkImageSourceType imageSource, id userInfo) {
         ASPerformBlockOnBackgroundThread(^{
           __typeof__(self) strongSelf = weakSelf;
           if (strongSelf == nil) {
@@ -720,7 +720,7 @@ - (void)_lazilyLoadImageIfNecessary
           if (newImage) {
             if (_delegateFlags.delegateDidLoadImageWithInfo) {
               calloutBlock = ^(ASNetworkImageNode *strongSelf) {
-                auto info = [[ASNetworkImageLoadInfo alloc] initWithURL:URL sourceType:imageSource downloadIdentifier:downloadIdentifier userInfo:userInfo];
+                let info = [[ASNetworkImageLoadInfo alloc] initWithURL:URL sourceType:imageSource downloadIdentifier:downloadIdentifier userInfo:userInfo];
                 [delegate imageNode:strongSelf didLoadImage:newImage info:info];
               };
             } else if (_delegateFlags.delegateDidLoadImage) {
@@ -736,7 +736,7 @@ - (void)_lazilyLoadImageIfNecessary
 
           if (calloutBlock) {
             ASPerformBlockOnMainThread(^{
-              if (auto strongSelf = weakSelf) {
+              if (let strongSelf = weakSelf) {
                 calloutBlock(strongSelf);
               }
             });

Source/ASRunLoopQueue.mm

@@ -220,13 +220,13 @@ - (void)releaseObjectInBackground:(id  _Nullable __strong *)objectPtr
   NSParameterAssert(objectPtr != NULL);
 
   // Cast to CFType so we can manipulate retain count manually.
-  auto cfPtr = (CFTypeRef *)(void *)objectPtr;
+  let cfPtr = (CFTypeRef *)(void *)objectPtr;
   if (!cfPtr || !*cfPtr) {
     return;
   }
 
   _lock.lock();
-  auto isFirstEntry = _queue.empty();
+  let isFirstEntry = _queue.empty();
   // Push the pointer into our queue and clear their pointer.
   // This "steals" the +1 from ARC and nils their pointer so they can't
   // access or release the object.
@@ -244,9 +244,9 @@ - (void)releaseObjectInBackground:(id  _Nullable __strong *)objectPtr
 - (void)drain
 {
   _lock.lock();
-  auto q = std::move(_queue);
+  let q = std::move(_queue);
   _lock.unlock();
-  for (auto ref : q) {
+  for (let ref : q) {
     // NOTE: Could check that retain count is 1 and retry later if not.
     CFRelease(ref);
   }
@@ -488,11 +488,11 @@ - (void)processQueue
   }
 
   // itemsToProcess will be empty if _queueConsumer == nil so no need to check again.
-  auto count = itemsToProcess.size();
+  let count = itemsToProcess.size();
   if (count > 0) {
     as_activity_scope_verbose(as_activity_create("Process run loop queue batch", _rootActivity, OS_ACTIVITY_FLAG_DEFAULT));
-    auto itemsEnd = itemsToProcess.cend();
-    for (auto iterator = itemsToProcess.begin(); iterator < itemsEnd; iterator++) {
+    let itemsEnd = itemsToProcess.cend();
+    for (var iterator = itemsToProcess.begin(); iterator < itemsEnd; iterator++) {
       __unsafe_unretained id value = *iterator;
       _queueConsumer(value, isQueueDrained && iterator == itemsEnd - 1);
       as_log_verbose(ASDisplayLog(), "processed %@", value);
@@ -711,11 +711,11 @@ - (void)processQueue
   }
 
   // itemsToProcess will be empty if _queueConsumer == nil so no need to check again.
-  auto count = itemsToProcess.size();
+  let count = itemsToProcess.size();
   if (count > 0) {
     as_activity_scope_verbose(as_activity_create("Process run loop queue batch", _rootActivity, OS_ACTIVITY_FLAG_DEFAULT));
-    auto itemsEnd = itemsToProcess.cend();
-    for (auto iterator = itemsToProcess.begin(); iterator < itemsEnd; iterator++) {
+    let itemsEnd = itemsToProcess.cend();
+    for (var iterator = itemsToProcess.begin(); iterator < itemsEnd; iterator++) {
       __unsafe_unretained id value = *iterator;
       [value prepareForCATransactionCommit];
       as_log_verbose(ASDisplayLog(), "processed %@", value);

Source/ASTableView.mm

@@ -676,7 +676,7 @@ - (nullable NSIndexPath *)indexPathForNode:(ASCellNode *)cellNode waitingIfNeede
 
 - (NSArray<ASCellNode *> *)visibleNodes
 {
-  auto elements = [self visibleElementsForRangeController:_rangeController];
+  let elements = [self visibleElementsForRangeController:_rangeController];
   return ASArrayByFlatMapping(elements, ASCollectionElement *e, e.node);
 }
 
@@ -762,7 +762,7 @@ - (void)layoutSubviews
       NSArray<ASCellNode *> *nodes = [_cellsForLayoutUpdates allObjects];
       [_cellsForLayoutUpdates removeAllObjects];
 
-      auto nodesSizeChanged = [[NSMutableArray<ASCellNode *> alloc] init];
+      let nodesSizeChanged = [[NSMutableArray<ASCellNode *> alloc] init];
       [_dataController relayoutNodes:nodes nodesSizeChanged:nodesSizeChanged];
       if (nodesSizeChanged.count > 0) {
         [self requeryNodeHeights];

Source/ASTextNode.mm

@@ -859,7 +859,7 @@ - (NSArray *)_rectsForTextRange:(NSRange)textRange measureOption:(ASTextKitRende
   ASLockScopeSelf();
 
   NSArray *rects = [[self _locked_renderer] rectsForTextRange:textRange measureOption:measureOption];
-  auto adjustedRects = [[NSMutableArray<NSValue *> alloc] init];
+  let adjustedRects = [[NSMutableArray<NSValue *> alloc] init];
 
   for (NSValue *rectValue in rects) {
     CGRect rect = [rectValue CGRectValue];
@@ -1308,7 +1308,7 @@ - (NSAttributedString *)_locked_prepareTruncationStringForDrawing:(NSAttributedS
     NSDictionary *originalStringAttributes = [originalString attributesAtIndex:originalStringLength-1 effectiveRange:NULL];
     [truncationString enumerateAttributesInRange:NSMakeRange(0, truncationString.length) options:0 usingBlock:
      ^(NSDictionary *attributes, NSRange range, BOOL *stop) {
-       NSMutableDictionary *futureTruncationAttributes = [NSMutableDictionary dictionaryWithDictionary:originalStringAttributes];
+       NSMutableDictionary *futureTruncationAttributes = [originalStringAttributes mutableCopy];
        [futureTruncationAttributes addEntriesFromDictionary:attributes];
        [truncationMutableString setAttributes:futureTruncationAttributes range:range];
      }];

Source/ASTextNode2.mm

@@ -408,7 +408,7 @@ + (ASTextLayout *)compatibleLayoutWithContainer:(ASTextContainer *)container
 
   CGRect containerBounds = (CGRect){ .size = container.size };
   {
-    for (auto &t : cacheValue->_layouts) {
+    for (let &t : cacheValue->_layouts) {
       CGSize constrainedSize = std::get<0>(t);
       ASTextLayout *layout = std::get<1>(t);
 
@@ -1135,7 +1135,7 @@ - (NSAttributedString *)_locked_prepareTruncationStringForDrawing:(NSAttributedS
     NSDictionary *originalStringAttributes = [originalString attributesAtIndex:originalStringLength-1 effectiveRange:NULL];
     [truncationString enumerateAttributesInRange:NSMakeRange(0, truncationString.length) options:0 usingBlock:
      ^(NSDictionary *attributes, NSRange range, BOOL *stop) {
-       NSMutableDictionary *futureTruncationAttributes = [NSMutableDictionary dictionaryWithDictionary:originalStringAttributes];
+       NSMutableDictionary *futureTruncationAttributes = [originalStringAttributes mutableCopy];
        [futureTruncationAttributes addEntriesFromDictionary:attributes];
        [truncationMutableString setAttributes:futureTruncationAttributes range:range];
      }];

Source/Base/ASBaseDefines.h

@@ -20,6 +20,14 @@
 #define AS_EXTERN FOUNDATION_EXTERN
 #define unowned __unsafe_unretained
 
+#if defined(__cplusplus)
+# define var auto
+# define let const auto
+#else
+# define var __auto_type
+# define let const __auto_type
+#endif
+
 #ifdef __GNUC__
 # define ASDISPLAYNODE_GNUC(major, minor) \
 (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))

Source/Details/ASBasicImageDownloader.mm

@@ -245,7 +245,7 @@ - (id)downloadImageWithURL:(NSURL *)URL
   // cause significant performance issues.
   dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
     // associate metadata with it
-    NSMutableDictionary *callbackData = [[NSMutableDictionary alloc] init];
+    let callbackData = [[NSMutableDictionary alloc] init];
     callbackData[kASBasicImageDownloaderContextCallbackQueue] = callbackQueue ? : dispatch_get_main_queue();
 
     if (downloadProgress) {
@@ -256,7 +256,7 @@ - (id)downloadImageWithURL:(NSURL *)URL
       callbackData[kASBasicImageDownloaderContextCompletionBlock] = [completion copy];
     }
 
-    [context addCallbackData:[NSDictionary dictionaryWithDictionary:callbackData]];
+    [context addCallbackData:[[NSDictionary alloc] initWithDictionary:callbackData]];
 
     // Create new task if necessary
     NSURLSessionDownloadTask *task = (NSURLSessionDownloadTask *)[context createSessionTaskIfNecessaryWithBlock:^(){return [_session downloadTaskWithURL:URL];}];

Source/Details/ASCollectionLayoutState.mm

@@ -159,7 +159,7 @@ - (UICollectionViewLayoutAttributes *)layoutAttributesForElement:(ASCollectionEl
   }
 
   // Use a set here because some items may span multiple pages
-  auto result = [[NSMutableSet<UICollectionViewLayoutAttributes *> alloc] init];
+  let result = [[NSMutableSet<UICollectionViewLayoutAttributes *> alloc] init];
   for (id pagePtr in pages) {
     ASPageCoordinate page = (ASPageCoordinate)pagePtr;
     NSArray<UICollectionViewLayoutAttributes *> *allAttrs = [_pageToLayoutAttributesTable objectForPage:page];

Source/Details/ASDataController.mm

@@ -214,7 +214,7 @@ - (void)_layoutNode:(ASCellNode *)node withConstrainedSize:(ASSizeRange)constrai
     return @[];
   }
 
-  auto indexPaths = [[NSMutableArray<NSIndexPath *> alloc] init];
+  let indexPaths = [[NSMutableArray<NSIndexPath *> alloc] init];
   if ([kind isEqualToString:ASDataControllerRowNodeKind]) {
     std::vector<NSInteger> counts = [self itemCountsFromDataSource];
     [sections enumerateRangesUsingBlock:^(NSRange range, BOOL * _Nonnull stop) {
@@ -671,7 +671,7 @@ - (void)updateWithChangeSet:(_ASHierarchyChangeSet *)changeSet
       [layoutDelegateClass calculateLayoutWithContext:layoutContext];
       completion();
     } else {
-      auto elementsToProcess = [[NSMutableArray<ASCollectionElement *> alloc] init];
+      let elementsToProcess = [[NSMutableArray<ASCollectionElement *> alloc] init];
       for (ASCollectionElement *element in newMap) {
         ASCellNode *nodeIfAllocated = element.nodeIfAllocated;
         if (nodeIfAllocated.shouldUseUIKitCell) {
@@ -827,10 +827,10 @@ - (void)relayoutNodes:(id<NSFastEnumeration>)nodes nodesSizeChanged:(NSMutableAr
   }
 
   id<ASDataControllerSource> dataSource = self.dataSource;
-  auto visibleMap = self.visibleMap;
-  auto pendingMap = self.pendingMap;
+  let visibleMap = self.visibleMap;
+  let pendingMap = self.pendingMap;
   for (ASCellNode *node in nodes) {
-    auto element = node.collectionElement;
+    let element = node.collectionElement;
     NSIndexPath *indexPathInPendingMap = [pendingMap indexPathForElement:element];
     // Ensure the element is present in both maps or skip it. If it's not in the visible map,
     // then we can't check the presented size. If it's not in the pending map, we can't get the constrained size.