1 files changed, 422 insertions, 0 deletions
diff --git a/dom/events/ContentEventHandler.h b/dom/events/ContentEventHandler.h
new file mode 100644
index 0000000000..68a12075b2
--- /dev/null
+++ b/dom/events/ContentEventHandler.h
@@ -0,0 +1,422 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ContentEventHandler_h_
+#define mozilla_ContentEventHandler_h_
+
+#include "mozilla/EventForwards.h"
+#include "mozilla/dom/Selection.h"
+#include "nsCOMPtr.h"
+#include "nsIFrame.h"
+#include "nsINode.h"
+
+class nsPresContext;
+class nsRange;
+
+struct nsRect;
+
+namespace mozilla {
+
+enum LineBreakType { LINE_BREAK_TYPE_NATIVE, LINE_BREAK_TYPE_XP };
+
+/*
+ * Query Content Event Handler
+ *   ContentEventHandler is a helper class for EventStateManager.
+ *   The platforms request some content informations, e.g., the selected text,
+ *   the offset of the selected text and the text for specified range.
+ *   This class answers to NS_QUERY_* events from actual contents.
+ */
+
+class MOZ_STACK_CLASS ContentEventHandler {
+ private:
+  /**
+   * RawRange is a helper class of ContentEventHandler class.  The caller is
+   * responsible for making sure the start/end nodes are in document order.
+   * This is enforced by assertions in DEBUG builds.
+   */
+  class MOZ_STACK_CLASS RawRange final {
+   public:
+    RawRange() = default;
+
+    void Clear() {
+      mRoot = nullptr;
+      mStart = RangeBoundary();
+      mEnd = RangeBoundary();
+    }
+
+    bool IsPositioned() const { return mStart.IsSet() && mEnd.IsSet(); }
+    bool Collapsed() const { return mStart == mEnd && IsPositioned(); }
+    nsINode* GetStartContainer() const { return mStart.Container(); }
+    nsINode* GetEndContainer() const { return mEnd.Container(); }
+    uint32_t StartOffset() const {
+      return *mStart.Offset(
+          RangeBoundary::OffsetFilter::kValidOrInvalidOffsets);
+    }
+    uint32_t EndOffset() const {
+      return *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets);
+    }
+    nsIContent* StartRef() const { return mStart.Ref(); }
+    nsIContent* EndRef() const { return mEnd.Ref(); }
+
+    const RangeBoundary& Start() const { return mStart; }
+    const RangeBoundary& End() const { return mEnd; }
+
+    // XXX: Make these use RangeBoundaries...
+    nsresult CollapseTo(const RawRangeBoundary& aBoundary) {
+      return SetStartAndEnd(aBoundary, aBoundary);
+    }
+    nsresult SetStart(const RawRangeBoundary& aStart);
+    nsresult SetEnd(const RawRangeBoundary& aEnd);
+
+    // NOTE: These helpers can hide performance problems, as they perform a
+    // search to find aStartOffset in aStartContainer.
+    nsresult SetStart(nsINode* aStartContainer, uint32_t aStartOffset) {
+      return SetStart(RawRangeBoundary(aStartContainer, aStartOffset));
+    }
+    nsresult SetEnd(nsINode* aEndContainer, uint32_t aEndOffset) {
+      return SetEnd(RawRangeBoundary(aEndContainer, aEndOffset));
+    }
+
+    nsresult SetEndAfter(nsINode* aEndContainer);
+    void SetStartAndEnd(const nsRange* aRange);
+    nsresult SetStartAndEnd(const RawRangeBoundary& aStart,
+                            const RawRangeBoundary& aEnd);
+
+    nsresult SelectNodeContents(nsINode* aNodeToSelectContents);
+
+   private:
+    inline void AssertStartIsBeforeOrEqualToEnd();
+
+    nsCOMPtr<nsINode> mRoot;
+
+    RangeBoundary mStart;
+    RangeBoundary mEnd;
+  };
+
+ public:
+  typedef dom::Selection Selection;
+
+  explicit ContentEventHandler(nsPresContext* aPresContext);
+
+  // Handle aEvent in the current process.
+  MOZ_CAN_RUN_SCRIPT nsresult
+  HandleQueryContentEvent(WidgetQueryContentEvent* aEvent);
+
+  // eQuerySelectedText event handler
+  MOZ_CAN_RUN_SCRIPT nsresult
+  OnQuerySelectedText(WidgetQueryContentEvent* aEvent);
+  // eQueryTextContent event handler
+  MOZ_CAN_RUN_SCRIPT nsresult
+  OnQueryTextContent(WidgetQueryContentEvent* aEvent);
+  // eQueryCaretRect event handler
+  MOZ_CAN_RUN_SCRIPT nsresult OnQueryCaretRect(WidgetQueryContentEvent* aEvent);
+  // eQueryTextRect event handler
+  MOZ_CAN_RUN_SCRIPT nsresult OnQueryTextRect(WidgetQueryContentEvent* aEvent);
+  // eQueryTextRectArray event handler
+  MOZ_CAN_RUN_SCRIPT nsresult
+  OnQueryTextRectArray(WidgetQueryContentEvent* aEvent);
+  // eQueryEditorRect event handler
+  MOZ_CAN_RUN_SCRIPT nsresult
+  OnQueryEditorRect(WidgetQueryContentEvent* aEvent);
+  // eQueryContentState event handler
+  MOZ_CAN_RUN_SCRIPT nsresult
+  OnQueryContentState(WidgetQueryContentEvent* aEvent);
+  // eQuerySelectionAsTransferable event handler
+  MOZ_CAN_RUN_SCRIPT nsresult
+  OnQuerySelectionAsTransferable(WidgetQueryContentEvent* aEvent);
+  // eQueryCharacterAtPoint event handler
+  MOZ_CAN_RUN_SCRIPT nsresult
+  OnQueryCharacterAtPoint(WidgetQueryContentEvent* aEvent);
+  // eQueryDOMWidgetHittest event handler
+  MOZ_CAN_RUN_SCRIPT nsresult
+  OnQueryDOMWidgetHittest(WidgetQueryContentEvent* aEvent);
+
+  // NS_SELECTION_* event
+  MOZ_CAN_RUN_SCRIPT nsresult OnSelectionEvent(WidgetSelectionEvent* aEvent);
+
+ protected:
+  RefPtr<dom::Document> mDocument;
+  // mSelection is typically normal selection but if OnQuerySelectedText()
+  // is called, i.e., handling eQuerySelectedText, it's the specified selection
+  // by WidgetQueryContentEvent::mInput::mSelectionType.
+  RefPtr<Selection> mSelection;
+  // mFirstSelectedRawRange is initialized from the first range of mSelection,
+  // if it exists.  Otherwise, it is reset by Clear().
+  RawRange mFirstSelectedRawRange;
+  nsCOMPtr<nsIContent> mRootContent;
+
+  MOZ_CAN_RUN_SCRIPT nsresult Init(WidgetQueryContentEvent* aEvent);
+  MOZ_CAN_RUN_SCRIPT nsresult Init(WidgetSelectionEvent* aEvent);
+
+  nsresult InitBasic(bool aRequireFlush = true);
+  MOZ_CAN_RUN_SCRIPT nsresult
+  InitCommon(SelectionType aSelectionType = SelectionType::eNormal,
+             bool aRequireFlush = true);
+  /**
+   * InitRootContent() computes the root content of current focused editor.
+   *
+   * @param aNormalSelection    This must be a Selection instance whose type is
+   *                            SelectionType::eNormal.
+   */
+  MOZ_CAN_RUN_SCRIPT nsresult InitRootContent(Selection* aNormalSelection);
+
+ public:
+  // FlatText means the text that is generated from DOM tree. The BR elements
+  // are replaced to native linefeeds. Other elements are ignored.
+
+  // NodePosition stores a pair of node and offset in the node.
+  // When mNode is an element and mOffset is 0, the start position means after
+  // the open tag of mNode.
+  // This is useful to receive one or more sets of them instead of nsRange.
+  // This type is intended to be used for short-lived operations, and is thus
+  // marked MOZ_STACK_CLASS.
+  struct MOZ_STACK_CLASS NodePosition : public RangeBoundary {
+    // Only when mNode is an element node and mOffset is 0, mAfterOpenTag is
+    // referred.
+    bool mAfterOpenTag = true;
+
+    NodePosition() = default;
+
+    NodePosition(nsINode* aContainer, int32_t aOffset)
+        : RangeBoundary(aContainer, aOffset) {}
+
+    NodePosition(nsINode* aContainer, nsIContent* aRef)
+        : RangeBoundary(aContainer, aRef) {}
+
+    explicit NodePosition(const nsIFrame::ContentOffsets& aContentOffsets)
+        : RangeBoundary(aContentOffsets.content, aContentOffsets.offset) {}
+
+   public:
+    bool operator==(const NodePosition& aOther) const {
+      return RangeBoundary::operator==(aOther) &&
+             mAfterOpenTag == aOther.mAfterOpenTag;
+    }
+
+    bool IsBeforeOpenTag() const {
+      return IsSet() && Container()->IsElement() && !Ref() && !mAfterOpenTag;
+    }
+    bool IsImmediatelyAfterOpenTag() const {
+      return IsSet() && Container()->IsElement() && !Ref() && mAfterOpenTag;
+    }
+  };
+
+  // NodePositionBefore isn't good name if Container() isn't an element node nor
+  // Offset() is not 0, though, when Container() is an element node and mOffset
+  // is 0, this is treated as before the open tag of Container().
+  struct NodePositionBefore final : public NodePosition {
+    NodePositionBefore(nsINode* aContainer, int32_t aOffset)
+        : NodePosition(aContainer, aOffset) {
+      mAfterOpenTag = false;
+    }
+
+    NodePositionBefore(nsINode* aContainer, nsIContent* aRef)
+        : NodePosition(aContainer, aRef) {
+      mAfterOpenTag = false;
+    }
+  };
+
+  // Get the flatten text length in the range.
+  // @param aStartPosition      Start node and offset in the node of the range.
+  // @param aEndPosition        End node and offset in the node of the range.
+  // @param aRootContent        The root content of the editor or document.
+  //                            aRootContent won't cause any text including
+  //                            line breaks.
+  // @param aLength             The result of the flatten text length of the
+  //                            range.
+  // @param aLineBreakType      Whether this computes flatten text length with
+  //                            native line breakers on the platform or
+  //                            with XP line breaker (\n).
+  // @param aIsRemovingNode     Should be true only when this is called from
+  //                            nsIMutationObserver::ContentRemoved().
+  //                            When this is true, aStartPosition.mNode should
+  //                            be the root node of removing nodes and mOffset
+  //                            should be 0 and aEndPosition.mNode should be
+  //                            same as aStartPosition.mNode and mOffset should
+  //                            be number of the children of mNode.
+  static nsresult GetFlatTextLengthInRange(const NodePosition& aStartPosition,
+                                           const NodePosition& aEndPosition,
+                                           nsIContent* aRootContent,
+                                           uint32_t* aLength,
+                                           LineBreakType aLineBreakType,
+                                           bool aIsRemovingNode = false);
+  // Computes the native text length between aStartOffset and aEndOffset of
+  // aContent.  aContent must be a text node.
+  static uint32_t GetNativeTextLength(nsIContent* aContent,
+                                      uint32_t aStartOffset,
+                                      uint32_t aEndOffset);
+  // Get the native text length of aContent.  aContent must be a text node.
+  static uint32_t GetNativeTextLength(nsIContent* aContent,
+                                      uint32_t aMaxLength = UINT32_MAX);
+  // Get the native text length which is inserted before aContent.
+  // aContent should be an element.
+  static uint32_t GetNativeTextLengthBefore(nsIContent* aContent,
+                                            nsINode* aRootNode);
+
+ protected:
+  // Get the text length of aContent.  aContent must be a text node.
+  static uint32_t GetTextLength(nsIContent* aContent,
+                                LineBreakType aLineBreakType,
+                                uint32_t aMaxLength = UINT32_MAX);
+  // Get the text length of a given range of a content node in
+  // the given line break type.
+  static uint32_t GetTextLengthInRange(nsIContent* aContent,
+                                       uint32_t aXPStartOffset,
+                                       uint32_t aXPEndOffset,
+                                       LineBreakType aLineBreakType);
+  // Get the contents in aContent (meaning all children of aContent) as plain
+  // text.  E.g., specifying mRootContent gets whole text in it.
+  // Note that the result is not same as .textContent.  The result is
+  // optimized for native IMEs.  For example, <br> element and some block
+  // elements causes "\n" (or "\r\n"), see also ShouldBreakLineBefore().
+  nsresult GenerateFlatTextContent(nsIContent* aContent, nsString& aString,
+                                   LineBreakType aLineBreakType);
+  // Get the contents of aRange as plain text.
+  nsresult GenerateFlatTextContent(const RawRange& aRawRange, nsString& aString,
+                                   LineBreakType aLineBreakType);
+  // Get offset of start of aRange.  Note that the result includes the length
+  // of line breaker caused by the start of aContent because aRange never
+  // includes the line breaker caused by its start node.
+  nsresult GetStartOffset(const RawRange& aRawRange, uint32_t* aOffset,
+                          LineBreakType aLineBreakType);
+  // Check if we should insert a line break before aContent.
+  // This should return false only when aContent is an html element which
+  // is typically used in a paragraph like <em>.
+  static bool ShouldBreakLineBefore(nsIContent* aContent, nsINode* aRootNode);
+  // Get the line breaker length.
+  static inline uint32_t GetBRLength(LineBreakType aLineBreakType);
+  static LineBreakType GetLineBreakType(WidgetQueryContentEvent* aEvent);
+  static LineBreakType GetLineBreakType(WidgetSelectionEvent* aEvent);
+  static LineBreakType GetLineBreakType(bool aUseNativeLineBreak);
+  // Returns focused content (including its descendant documents).
+  nsIContent* GetFocusedContent();
+  // QueryContentRect() sets the rect of aContent's frame(s) to aEvent.
+  nsresult QueryContentRect(nsIContent* aContent,
+                            WidgetQueryContentEvent* aEvent);
+  // Initialize aRawRange from the offset of FlatText and the text length.
+  // If aExpandToClusterBoundaries is true, the start offset and the end one are
+  // expanded to nearest cluster boundaries.
+  nsresult SetRawRangeFromFlatTextOffset(RawRange* aRawRange, uint32_t aOffset,
+                                         uint32_t aLength,
+                                         LineBreakType aLineBreakType,
+                                         bool aExpandToClusterBoundaries,
+                                         uint32_t* aNewOffset = nullptr,
+                                         nsIContent** aLastTextNode = nullptr);
+  // If the aCollapsedRawRange isn't in text node but next to a text node,
+  // this method modifies it in the text node.  Otherwise, not modified.
+  nsresult AdjustCollapsedRangeMaybeIntoTextNode(RawRange& aCollapsedRawRange);
+  // Convert the frame relative offset to be relative to the root frame of the
+  // root presContext (but still measured in appUnits of aFrame's presContext).
+  nsresult ConvertToRootRelativeOffset(nsIFrame* aFrame, nsRect& aRect);
+  // Expand aXPOffset to the nearest offset in cluster boundary. aForward is
+  // true, it is expanded to forward.
+  nsresult ExpandToClusterBoundary(nsIContent* aContent, bool aForward,
+                                   uint32_t* aXPOffset);
+
+  typedef nsTArray<mozilla::FontRange> FontRangeArray;
+  static void AppendFontRanges(FontRangeArray& aFontRanges,
+                               nsIContent* aContent, uint32_t aBaseOffset,
+                               uint32_t aXPStartOffset, uint32_t aXPEndOffset,
+                               LineBreakType aLineBreakType);
+  nsresult GenerateFlatFontRanges(const RawRange& aRawRange,
+                                  FontRangeArray& aFontRanges,
+                                  uint32_t& aLength,
+                                  LineBreakType aLineBreakType);
+  nsresult QueryTextRectByRange(const RawRange& aRawRange,
+                                LayoutDeviceIntRect& aRect,
+                                WritingMode& aWritingMode);
+
+  struct MOZ_STACK_CLASS FrameAndNodeOffset final {
+    // mFrame is safe since this can live in only stack class and
+    // ContentEventHandler doesn't modify layout after
+    // ContentEventHandler::Init() flushes pending layout.  In other words,
+    // this struct shouldn't be used before calling
+    // ContentEventHandler::Init().
+    nsIFrame* mFrame;
+    // offset in the node of mFrame
+    int32_t mOffsetInNode;
+
+    FrameAndNodeOffset() : mFrame(nullptr), mOffsetInNode(-1) {}
+
+    FrameAndNodeOffset(nsIFrame* aFrame, int32_t aStartOffsetInNode)
+        : mFrame(aFrame), mOffsetInNode(aStartOffsetInNode) {}
+
+    nsIFrame* operator->() { return mFrame; }
+    const nsIFrame* operator->() const { return mFrame; }
+    operator nsIFrame*() { return mFrame; }
+    operator const nsIFrame*() const { return mFrame; }
+    bool IsValid() const { return mFrame && mOffsetInNode >= 0; }
+  };
+  // Get first frame after the start of the given range for computing text rect.
+  // This returns invalid FrameAndNodeOffset if there is no content which
+  // should affect to computing text rect in the range.  mOffsetInNode is start
+  // offset in the frame.
+  FrameAndNodeOffset GetFirstFrameInRangeForTextRect(const RawRange& aRawRange);
+
+  // Get last frame before the end of the given range for computing text rect.
+  // This returns invalid FrameAndNodeOffset if there is no content which
+  // should affect to computing text rect in the range.  mOffsetInNode is end
+  // offset in the frame.
+  FrameAndNodeOffset GetLastFrameInRangeForTextRect(const RawRange& aRawRange);
+
+  struct MOZ_STACK_CLASS FrameRelativeRect final {
+    // mRect is relative to the mBaseFrame's position.
+    nsRect mRect;
+    nsIFrame* mBaseFrame;
+
+    FrameRelativeRect() : mBaseFrame(nullptr) {}
+
+    explicit FrameRelativeRect(nsIFrame* aBaseFrame) : mBaseFrame(aBaseFrame) {}
+
+    FrameRelativeRect(const nsRect& aRect, nsIFrame* aBaseFrame)
+        : mRect(aRect), mBaseFrame(aBaseFrame) {}
+
+    bool IsValid() const { return mBaseFrame != nullptr; }
+
+    // Returns an nsRect relative to aBaseFrame instead of mBaseFrame.
+    nsRect RectRelativeTo(nsIFrame* aBaseFrame) const;
+  };
+
+  // Returns a rect for line breaker before the node of aFrame (If aFrame is
+  // a <br> frame or a block level frame, it causes a line break at its
+  // element's open tag, see also ShouldBreakLineBefore()).  Note that this
+  // doesn't check if aFrame should cause line break in non-debug build.
+  FrameRelativeRect GetLineBreakerRectBefore(nsIFrame* aFrame);
+
+  // Returns a line breaker rect after aTextContent as there is a line breaker
+  // immediately after aTextContent.  This is useful when following block
+  // element causes a line break before it and it needs to compute the line
+  // breaker's rect.  For example, if there is |<p>abc</p><p>def</p>|, the
+  // rect of 2nd <p>'s line breaker should be at right of "c" in the first
+  // <p>, not the start of 2nd <p>.  The result is relative to the last text
+  // frame which represents the last character of aTextContent.
+  FrameRelativeRect GuessLineBreakerRectAfter(nsIContent* aTextContent);
+
+  // Returns a guessed first rect.  I.e., it may be different from actual
+  // caret when selection is collapsed at start of aFrame.  For example, this
+  // guess the caret rect only with the content box of aFrame and its font
+  // height like:
+  // +-aFrame----------------- (border box)
+  // |
+  // |  +--------------------- (content box)
+  // |  | I
+  //      ^ guessed caret rect
+  // However, actual caret is computed with more information like line-height,
+  // child frames of aFrame etc.  But this does not emulate actual caret
+  // behavior exactly for simpler and faster code because it's difficult and
+  // we're not sure it's worthwhile to do it with complicated implementation.
+  FrameRelativeRect GuessFirstCaretRectIn(nsIFrame* aFrame);
+
+  // Make aRect non-empty.  If width and/or height is 0, these methods set them
+  // to 1.  Note that it doesn't set nsRect's width nor height to one device
+  // pixel because using nsRect::ToOutsidePixels() makes actual width or height
+  // to 2 pixels because x and y may not be aligned to device pixels.
+  void EnsureNonEmptyRect(nsRect& aRect) const;
+  void EnsureNonEmptyRect(LayoutDeviceIntRect& aRect) const;
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_ContentEventHandler_h_