Rename CK classes to AS classes

AsyncDisplayKit/TextKit/ASTextKitHelpers.mm

@@ -0,0 +1,57 @@
+/* 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 "ASTextKitHelpers.h"
+
+@interface ASTextKitComponents ()
+
+// read-write redeclarations
+@property (nonatomic, strong, readwrite) NSTextStorage *textStorage;
+@property (nonatomic, strong, readwrite) NSTextContainer *textContainer;
+@property (nonatomic, strong, readwrite) NSLayoutManager *layoutManager;
+
+@end
+
+@implementation ASTextKitComponents
+
++ (ASTextKitComponents *)componentsWithAttributedSeedString:(NSAttributedString *)attributedSeedString
+                                          textContainerSize:(CGSize)textContainerSize
+{
+  ASTextKitComponents *components = [[ASTextKitComponents alloc] init];
+
+  // Create the TextKit component stack with our default configuration.
+  components.textStorage = (attributedSeedString ? [[NSTextStorage alloc] initWithAttributedString:attributedSeedString] : [[NSTextStorage alloc] init]);
+
+  components.layoutManager = [[NSLayoutManager alloc] init];
+  [components.textStorage addLayoutManager:components.layoutManager];
+
+  components.textContainer = [[NSTextContainer alloc] initWithSize:textContainerSize];
+  components.textContainer.lineFragmentPadding = 0.0; // We want the text laid out up to the very edges of the text-view.
+  [components.layoutManager addTextContainer:components.textContainer];
+
+  return components;
+}
+
+- (CGSize)sizeForConstrainedWidth:(CGFloat)constrainedWidth
+{
+  ASTextKitComponents *components = self;
+
+  // If our text-view's width is already the constrained width, we can use our existing TextKit stack for this sizing calculation.
+  // Otherwise, we create a temporary stack to size for `constrainedWidth`.
+  if (CGRectGetWidth(components.textView.bounds) != constrainedWidth) {
+    components = [ASTextKitComponents componentsWithAttributedSeedString:components.textStorage textContainerSize:CGSizeMake(constrainedWidth, FLT_MAX)];
+  }
+
+  // Force glyph generation and layout, which may not have happened yet (and isn't triggered by -usedRectForTextContainer:).
+  [components.layoutManager ensureLayoutForTextContainer:components.textContainer];
+  CGSize textSize = [components.layoutManager usedRectForTextContainer:components.textContainer].size;
+
+  return textSize;
+}
+
+@end