From 943cae7eb9b79d0c89b274f0ed13201a9e1bd3d8 Mon Sep 17 00:00:00 2001
From: Scott Goodson <scottg@pinterest.com>
Date: Sat, 28 Nov 2015 17:45:43 -0800
Subject: [PATCH] Placeholder implementation of -setInterfaceState:.

---
 AsyncDisplayKit/ASDisplayNode.h  |  2 +-
 AsyncDisplayKit/ASDisplayNode.mm | 33 ++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/AsyncDisplayKit/ASDisplayNode.h b/AsyncDisplayKit/ASDisplayNode.h
index 62663267ec..51adccbc1c 100644
--- a/AsyncDisplayKit/ASDisplayNode.h
+++ b/AsyncDisplayKit/ASDisplayNode.h
@@ -46,7 +46,7 @@ typedef NS_OPTIONS(NSUInteger, ASInterfaceState)
   ASInterfaceStateMeasureLayout = 1 << 1,
   /** The element is likely enough to come onscreen that disk and/or network data required for display should be fetched. */
   ASInterfaceStateFetchData     = 1 << 2,
-  /** The elemant is very likely to become visible, and concurrent rendering should be executed for any -setNeedsDisplay. */
+  /** The element is very likely to become visible, and concurrent rendering should be executed for any -setNeedsDisplay. */
   ASInterfaceStateDisplay       = 1 << 3,
   /** The element is physically onscreen by at least 1 pixel.
    In practice, all other bit fields should also be set when this flag is set. */
diff --git a/AsyncDisplayKit/ASDisplayNode.mm b/AsyncDisplayKit/ASDisplayNode.mm
index 394c050128..4095552b77 100644
--- a/AsyncDisplayKit/ASDisplayNode.mm
+++ b/AsyncDisplayKit/ASDisplayNode.mm
@@ -1692,6 +1692,39 @@ void recursivelyEnsureDisplayForLayer(CALayer *layer)
 - (void)setInterfaceState:(ASInterfaceState)interfaceState
 {
   if (interfaceState != _interfaceState) {
+    if ((interfaceState & ASInterfaceStateMeasureLayout) != (_interfaceState & ASInterfaceStateMeasureLayout)) {
+      // Trigger asynchronous measurement if it is not already cached or being calculated.
+    }
+    
+    // Entered or exited data loading state.
+    if ((interfaceState & ASInterfaceStateFetchData) != (_interfaceState & ASInterfaceStateFetchData)) {
+      if (interfaceState & ASInterfaceStateFetchData) {
+        [self fetchData];
+      } else {
+        [self clearFetchedData];
+      }
+    }
+
+    // Entered or exited contents rendering state.
+    if ((interfaceState & ASInterfaceStateDisplay) != (_interfaceState & ASInterfaceStateDisplay)) {
+      if (interfaceState & ASInterfaceStateDisplay) {
+        // Once the working window is eliminated (ASRangeHandlerRender), trigger display directly here.
+        [self setDisplaySuspended:NO];
+      } else {
+        [self setDisplaySuspended:YES];
+        [self clearContents];
+      }
+    }
+
+    // Entered or exited data loading state.
+    if ((interfaceState & ASInterfaceStateVisible) != (_interfaceState & ASInterfaceStateVisible)) {
+      if (interfaceState & ASInterfaceStateVisible) {
+        // Consider providing a -didBecomeVisible.
+      } else {
+        // Consider providing a -didBecomeInvisible.
+      }
+    }
+    
     _interfaceState = interfaceState;
   }
 }