From ed909b619c8145958a7d17596b2aef34b0f3d19b Mon Sep 17 00:00:00 2001
From: Valentin Shergin <shergin@fb.com>
Date: Fri, 22 Nov 2019 20:05:04 -0800
Subject: [PATCH] Fabric: Removing AttributedString::Fragment::shadowNode

Summary:
Before this change `AttributedString::Fragment` had two ShadowView objects (`shadowView` and `parentShadowView`). This diff unifies those two things into one. That allows us to save some CPU and memory and makes things a bit simpler. Besides that, now the length of NSAttributedString and AttributedString is now always the same (it's one Unicode character for an attachment for both).

Changelog: [Internal] Fabric-specific internal change.

Reviewed By: JoshuaGross

Differential Revision: D18607658

fbshipit-source-id: 502ae244e98a52694adc0d646650f8ea0d7922ae
---
 .../fabric/attributedstring/AttributedString.cpp | 16 ++++++++++------
 .../fabric/attributedstring/AttributedString.h   | 10 ++++++++--
 .../text/basetext/BaseTextShadowNode.cpp         |  3 ++-
 .../platform/ios/RCTAttributedTextUtils.mm       |  5 ++---
 4 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/ReactCommon/fabric/attributedstring/AttributedString.cpp b/ReactCommon/fabric/attributedstring/AttributedString.cpp
index 1902c7a9af3..974d214ea69 100644
--- a/ReactCommon/fabric/attributedstring/AttributedString.cpp
+++ b/ReactCommon/fabric/attributedstring/AttributedString.cpp
@@ -17,13 +17,17 @@ using Fragments = AttributedString::Fragments;
 
 #pragma mark - Fragment
 
+std::string Fragment::AttachmentCharacter() {
+  return "\uFFFC"; // Unicode `OBJECT REPLACEMENT CHARACTER`
+}
+
+bool Fragment::isAttachment() const {
+  return string == AttachmentCharacter();
+}
+
 bool Fragment::operator==(const Fragment &rhs) const {
-  return std::tie(string, textAttributes, shadowView, parentShadowView) ==
-      std::tie(
-             rhs.string,
-             rhs.textAttributes,
-             rhs.shadowView,
-             rhs.parentShadowView);
+  return std::tie(string, textAttributes, parentShadowView) ==
+      std::tie(rhs.string, rhs.textAttributes, rhs.parentShadowView);
 }
 
 bool Fragment::operator!=(const Fragment &rhs) const {
diff --git a/ReactCommon/fabric/attributedstring/AttributedString.h b/ReactCommon/fabric/attributedstring/AttributedString.h
index 08e4bd11567..7a952e4bfcf 100644
--- a/ReactCommon/fabric/attributedstring/AttributedString.h
+++ b/ReactCommon/fabric/attributedstring/AttributedString.h
@@ -35,11 +35,18 @@ class AttributedString : public Sealable, public DebugStringConvertible {
  public:
   class Fragment {
    public:
+    static std::string AttachmentCharacter();
+
     std::string string;
     TextAttributes textAttributes;
-    ShadowView shadowView;
     ShadowView parentShadowView;
 
+    /*
+     * Returns true is the Fragment represents an attachment.
+     * Equivalent to `string == AttachmentCharacter()`.
+     */
+    bool isAttachment() const;
+
     bool operator==(const Fragment &rhs) const;
     bool operator!=(const Fragment &rhs) const;
   };
@@ -99,7 +106,6 @@ struct hash<facebook::react::AttributedString::Fragment> {
         0,
         fragment.string,
         fragment.textAttributes,
-        fragment.shadowView,
         fragment.parentShadowView);
   }
 };
diff --git a/ReactCommon/fabric/components/text/basetext/BaseTextShadowNode.cpp b/ReactCommon/fabric/components/text/basetext/BaseTextShadowNode.cpp
index 927445be33e..d873d6025a6 100644
--- a/ReactCommon/fabric/components/text/basetext/BaseTextShadowNode.cpp
+++ b/ReactCommon/fabric/components/text/basetext/BaseTextShadowNode.cpp
@@ -54,7 +54,8 @@ AttributedString BaseTextShadowNode::getAttributedString(
 
     // Any other kind of ShadowNode
     auto fragment = AttributedString::Fragment{};
-    fragment.shadowView = ShadowView(*childNode);
+    fragment.string = AttributedString::Fragment::AttachmentCharacter();
+    fragment.parentShadowView = ShadowView(*childNode);
     fragment.textAttributes = textAttributes;
     attributedString.appendFragment(fragment);
   }
diff --git a/ReactCommon/fabric/textlayoutmanager/platform/ios/RCTAttributedTextUtils.mm b/ReactCommon/fabric/textlayoutmanager/platform/ios/RCTAttributedTextUtils.mm
index 73b1c0e5133..b5ffa1ab382 100644
--- a/ReactCommon/fabric/textlayoutmanager/platform/ios/RCTAttributedTextUtils.mm
+++ b/ReactCommon/fabric/textlayoutmanager/platform/ios/RCTAttributedTextUtils.mm
@@ -224,9 +224,8 @@ NSAttributedString *RCTNSAttributedStringFromAttributedString(const AttributedSt
   for (auto fragment : attributedString.getFragments()) {
     NSAttributedString *nsAttributedStringFragment;
 
-    auto layoutMetrics = fragment.shadowView.layoutMetrics;
-
-    if (layoutMetrics != EmptyLayoutMetrics) {
+    if (fragment.isAttachment()) {
+      auto layoutMetrics = fragment.parentShadowView.layoutMetrics;
       CGRect bounds = {.origin = {.x = layoutMetrics.frame.origin.x, .y = layoutMetrics.frame.origin.y},
                        .size = {.width = layoutMetrics.frame.size.width, .height = layoutMetrics.frame.size.height}};