From acee8474e05ac1d5d194972280c177b98a4cf755 Mon Sep 17 00:00:00 2001
From: Mirko Brodesser <mbrodesser@mozilla.com>
Date: Wed, 27 Jan 2021 09:43:35 +0000
Subject: [PATCH] Bug 1688832: part 4) Add
 `AccessibleCaretManager::SelectionStringifyer`. r=TYLin

Will help to simplify `AccessibleCaretManager::Dispatch...`.

Differential Revision: https://phabricator.services.mozilla.com/D102920
---
 layout/base/AccessibleCaretManager.cpp | 17 +++++----
 layout/base/AccessibleCaretManager.h   | 53 ++++++++++++++++----------
 2 files changed, 43 insertions(+), 27 deletions(-)

diff --git a/layout/base/AccessibleCaretManager.cpp b/layout/base/AccessibleCaretManager.cpp
index a7a623d717fc..5d4c890fa917 100644
--- a/layout/base/AccessibleCaretManager.cpp
+++ b/layout/base/AccessibleCaretManager.cpp
@@ -77,7 +77,7 @@ std::ostream& operator<<(
 #undef AC_PROCESS_ENUM_TO_STREAM
 
 AccessibleCaretManager::AccessibleCaretManager(PresShell* aPresShell)
-    : mPresShell(aPresShell) {
+    : mSelectionStringifyer{mLayoutFlusher}, mPresShell{aPresShell} {
   if (!mPresShell) {
     return;
   }
@@ -838,13 +838,16 @@ already_AddRefed<nsFrameSelection> AccessibleCaretManager::GetFrameSelection()
 }
 
 nsAutoString AccessibleCaretManager::StringifiedSelection() const {
-  nsAutoString str;
   RefPtr<Selection> selection = GetSelection();
-  if (selection) {
-    selection->Stringify(str, mLayoutFlusher.mAllowFlushing
-                                  ? Selection::FlushFrames::Yes
-                                  : Selection::FlushFrames::No);
-  }
+  return mSelectionStringifyer.Stringify(*selection);
+}
+
+nsAutoString AccessibleCaretManager::SelectionStringifyer::Stringify(
+    Selection& aSelection) const {
+  nsAutoString str;
+  aSelection.Stringify(str, mLayoutFlusher.mAllowFlushing
+                                ? Selection::FlushFrames::Yes
+                                : Selection::FlushFrames::No);
   return str;
 }
 
diff --git a/layout/base/AccessibleCaretManager.h b/layout/base/AccessibleCaretManager.h
index 6759199b6889..632c26493ada 100644
--- a/layout/base/AccessibleCaretManager.h
+++ b/layout/base/AccessibleCaretManager.h
@@ -245,8 +245,39 @@ class AccessibleCaretManager {
   dom::Selection* GetSelection() const;
   already_AddRefed<nsFrameSelection> GetFrameSelection() const;
 
-  MOZ_CAN_RUN_SCRIPT
-  nsAutoString StringifiedSelection() const;
+  class LayoutFlusher final {
+   public:
+    ~LayoutFlusher();
+
+    MOZ_CAN_RUN_SCRIPT void MaybeFlush(const PresShell& aPresShell);
+
+    // Set to false to disallow flushing layout in some callbacks such as
+    // OnReflow(), OnScrollStart(), OnScrollStart(), or
+    // OnScrollPositionChanged().
+    bool mAllowFlushing = true;
+
+   private:
+    // Whether we're flushing layout, used for sanity-checking.
+    bool mFlushing = false;
+  };
+
+  LayoutFlusher mLayoutFlusher;
+
+  MOZ_CAN_RUN_SCRIPT nsAutoString StringifiedSelection() const;
+
+  class SelectionStringifyer final {
+   public:
+    explicit SelectionStringifyer(LayoutFlusher& aLayoutFlusher)
+        : mLayoutFlusher{aLayoutFlusher} {}
+
+    [[nodiscard]] MOZ_CAN_RUN_SCRIPT nsAutoString
+    Stringify(dom::Selection& aSelection) const;
+
+   private:
+    LayoutFlusher mLayoutFlusher;
+  };
+
+  SelectionStringifyer mSelectionStringifyer;
 
   // Get the union of all the child frame scrollable overflow rects for aFrame,
   // which is used as a helper function to restrict the area where the caret can
@@ -352,24 +383,6 @@ class AccessibleCaretManager {
   // Set to true in OnScrollStart() and set to false in OnScrollEnd().
   bool mIsScrollStarted = false;
 
-  class LayoutFlusher final {
-   public:
-    ~LayoutFlusher();
-
-    MOZ_CAN_RUN_SCRIPT void MaybeFlush(const PresShell& aPresShell);
-
-    // Set to false to disallow flushing layout in some callbacks such as
-    // OnReflow(), OnScrollStart(), OnScrollStart(), or
-    // OnScrollPositionChanged().
-    bool mAllowFlushing = true;
-
-  private:
-    // Whether we're flushing layout, used for sanity-checking.
-    bool mFlushing = false;
-  };
-
-  LayoutFlusher mLayoutFlusher;
-
   // Set to True if one of the caret's position is changed in last update.
   bool mIsCaretPositionChanged = false;