third_party/WebKit/Source/core/editing/CaretDisplayItemClient.cpp

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#include "core/editing/CaretDisplayItemClient.h"

#include "core/editing/EditingUtilities.h"
#include "core/editing/LocalCaretRect.h"
#include "core/editing/PositionWithAffinity.h"
#include "core/editing/VisibleUnits.h"
#include "core/frame/LocalFrameView.h"
#include "core/frame/Settings.h"
#include "core/layout/LayoutBlock.h"
#include "core/layout/LayoutView.h"
#include "core/paint/FindPaintOffsetAndVisualRectNeedingUpdate.h"
#include "core/paint/ObjectPaintInvalidator.h"
#include "core/paint/PaintInfo.h"
#include "core/paint/PaintInvalidator.h"
#include "core/paint/PaintLayer.h"
#include "platform/graphics/GraphicsContext.h"
#include "platform/graphics/paint/DrawingRecorder.h"

namespace blink {

CaretDisplayItemClient::CaretDisplayItemClient() = default;
CaretDisplayItemClient::~CaretDisplayItemClient() = default;

static inline bool CaretRendersInsideNode(const Node* node) {
  return node && !IsDisplayInsideTable(node) && !EditingIgnoresContent(*node);
}

LayoutBlock* CaretDisplayItemClient::CaretLayoutBlock(const Node* node) {
  if (!node)
    return nullptr;

  LayoutObject* layout_object = node->GetLayoutObject();
  if (!layout_object)
    return nullptr;

  // if caretNode is a block and caret is inside it then caret should be painted
  // by that block
  bool painted_by_block =
      layout_object->IsLayoutBlock() && CaretRendersInsideNode(node);
  // TODO(yoichio): This function is called at least
  // DocumentLifeCycle::LayoutClean but caretRendersInsideNode above can
  // layout. Thus |node->layoutObject()| can be changed then this is bad
  // design. We should make caret painting algorithm clean.
  CHECK_EQ(layout_object, node->GetLayoutObject())
      << "Layout tree should not changed";
  return painted_by_block ? ToLayoutBlock(layout_object)
                          : layout_object->ContainingBlock();
}

static LayoutRect MapCaretRectToCaretPainter(const LayoutBlock* caret_block,
                                             const LocalCaretRect& caret_rect) {
  // FIXME: This shouldn't be called on un-rooted subtrees.
  // FIXME: This should probably just use mapLocalToAncestor.
  // Compute an offset between the caretLayoutItem and the caretPainterItem.

  LayoutObject* caret_layout_object =
      const_cast<LayoutObject*>(caret_rect.layout_object);
  DCHECK(caret_layout_object->IsDescendantOf(caret_block));

  LayoutRect result_rect = caret_rect.rect;
  caret_block->FlipForWritingMode(result_rect);
  while (caret_layout_object != caret_block) {
    LayoutObject* container_object = caret_layout_object->Container();
    if (!container_object)
      return LayoutRect();
    result_rect.Move(
        caret_layout_object->OffsetFromContainer(container_object));
    caret_layout_object = container_object;
  }
  return result_rect;
}

LayoutRect CaretDisplayItemClient::ComputeCaretRect(
    const PositionWithAffinity& caret_position) {
  if (caret_position.IsNull())
    return LayoutRect();

  DCHECK(caret_position.AnchorNode()->GetLayoutObject());

  // First compute a rect local to the layoutObject at the selection start.
  const LocalCaretRect& caret_rect = LocalCaretRectOfPosition(caret_position);

  // Get the layoutObject that will be responsible for painting the caret
  // (which is either the layoutObject we just found, or one of its containers).
  const LayoutBlock* caret_block =
      CaretLayoutBlock(caret_position.AnchorNode());
  return MapCaretRectToCaretPainter(caret_block, caret_rect);
}

void CaretDisplayItemClient::ClearPreviousVisualRect(const LayoutBlock& block) {
  if (block == layout_block_)
    visual_rect_ = LayoutRect();
  if (block == previous_layout_block_)
    visual_rect_in_previous_layout_block_ = LayoutRect();
}

void CaretDisplayItemClient::LayoutBlockWillBeDestroyed(
    const LayoutBlock& block) {
  if (block == layout_block_)
    layout_block_ = nullptr;
  if (block == previous_layout_block_)
    previous_layout_block_ = nullptr;
}

void CaretDisplayItemClient::UpdateStyleAndLayoutIfNeeded(
    const PositionWithAffinity& caret_position) {
  // This method may be called multiple times (e.g. in partial lifecycle
  // updates) before a paint invalidation. We should save m_previousLayoutBlock
  // and m_visualRectInPreviousLayoutBlock only if they have not been saved
  // since the last paint invalidation to ensure the caret painted in the
  // previous paint invalidated block will be invalidated. We don't care about
  // intermediate changes of layoutBlock because they are not painted.
  if (!previous_layout_block_) {
    previous_layout_block_ = layout_block_;
    visual_rect_in_previous_layout_block_ = visual_rect_;
  }

  LayoutBlock* new_layout_block = CaretLayoutBlock(caret_position.AnchorNode());
  if (new_layout_block != layout_block_) {
    if (layout_block_)
      layout_block_->SetMayNeedPaintInvalidation();
    layout_block_ = new_layout_block;
    visual_rect_ = LayoutRect();
    if (new_layout_block) {
      needs_paint_invalidation_ = true;
      if (new_layout_block == previous_layout_block_) {
        // The caret has disappeared and is reappearing in the same block,
        // since the last paint invalidation. Set m_visualRect as if the caret
        // has always been there as paint invalidation doesn't care about the
        // intermediate changes.
        visual_rect_ = visual_rect_in_previous_layout_block_;
      }
    }
  }

  if (!new_layout_block) {
    color_ = Color();
    local_rect_ = LayoutRect();
    return;
  }

  Color new_color;
  if (caret_position.AnchorNode()) {
    new_color = caret_position.AnchorNode()->GetLayoutObject()->ResolveColor(
        GetCSSPropertyCaretColor());
  }
  if (new_color != color_) {
    needs_paint_invalidation_ = true;
    color_ = new_color;
  }

  LayoutRect new_local_rect = ComputeCaretRect(caret_position);
  if (new_local_rect != local_rect_) {
    needs_paint_invalidation_ = true;
    local_rect_ = new_local_rect;
  }

  if (needs_paint_invalidation_)
    new_layout_block->SetMayNeedPaintInvalidation();
}

void CaretDisplayItemClient::InvalidatePaint(
    const LayoutBlock& block,
    const PaintInvalidatorContext& context) {
  if (block == layout_block_) {
    InvalidatePaintInCurrentLayoutBlock(context);
    return;
  }

  if (block == previous_layout_block_)
    InvalidatePaintInPreviousLayoutBlock(context);
}

void CaretDisplayItemClient::InvalidatePaintInPreviousLayoutBlock(
    const PaintInvalidatorContext& context) {
  DCHECK(previous_layout_block_);

  ObjectPaintInvalidatorWithContext object_invalidator(*previous_layout_block_,
                                                       context);
  // For SPv175 raster invalidation will be done in PaintController.
  if (!RuntimeEnabledFeatures::SlimmingPaintV175Enabled() &&
      !IsImmediateFullPaintInvalidationReason(
          previous_layout_block_->FullPaintInvalidationReason())) {
    object_invalidator.InvalidatePaintRectangleWithContext(
        visual_rect_in_previous_layout_block_, PaintInvalidationReason::kCaret);
  }

  context.painting_layer->SetNeedsRepaint();
  object_invalidator.InvalidateDisplayItemClient(
      *this, PaintInvalidationReason::kCaret);
  previous_layout_block_ = nullptr;
}

void CaretDisplayItemClient::InvalidatePaintInCurrentLayoutBlock(
    const PaintInvalidatorContext& context) {
  DCHECK(layout_block_);

  LayoutRect new_visual_rect;
#if DCHECK_IS_ON()
  FindVisualRectNeedingUpdateScope finder(*layout_block_, context, visual_rect_,
                                          new_visual_rect);
#endif
  if (context.NeedsVisualRectUpdate(*layout_block_)) {
    if (!local_rect_.IsEmpty()) {
      new_visual_rect = local_rect_;
      context.MapLocalRectToVisualRectInBacking(*layout_block_,
                                                new_visual_rect);

      if (layout_block_->UsesCompositedScrolling()) {
        // The caret should use scrolling coordinate space.
        DCHECK(layout_block_ == context.paint_invalidation_container);
        new_visual_rect.Move(
            LayoutSize(layout_block_->ScrolledContentOffset()));
      }
    }
  } else {
    new_visual_rect = visual_rect_;
  }

  if (layout_block_ == previous_layout_block_)
    previous_layout_block_ = nullptr;

  ObjectPaintInvalidatorWithContext object_invalidator(*layout_block_, context);
  if (!needs_paint_invalidation_ && new_visual_rect == visual_rect_) {
    // The caret may change paint offset without changing visual rect, and we
    // need to invalidate the display item client if the block is doing full
    // paint invalidation.
    if (IsImmediateFullPaintInvalidationReason(
            layout_block_->FullPaintInvalidationReason()) ||
        // For SPv1, kSubtreeInvalidationChecking may hint change of
        // paint offset. See ObjectPaintInvalidatorWithContext::
        // invalidatePaintIfNeededWithComputedReason().
        (!RuntimeEnabledFeatures::SlimmingPaintV175Enabled() &&
         (context.subtree_flags &
          PaintInvalidatorContext::kSubtreeInvalidationChecking))) {
      object_invalidator.InvalidateDisplayItemClient(
          *this, PaintInvalidationReason::kCaret);
    }
    return;
  }

  needs_paint_invalidation_ = false;

  if (!RuntimeEnabledFeatures::SlimmingPaintV175Enabled() &&
      !IsImmediateFullPaintInvalidationReason(
          layout_block_->FullPaintInvalidationReason())) {
    object_invalidator.FullyInvalidatePaint(PaintInvalidationReason::kCaret,
                                            visual_rect_, new_visual_rect);
  }

  context.painting_layer->SetNeedsRepaint();
  object_invalidator.InvalidateDisplayItemClient(
      *this, PaintInvalidationReason::kCaret);

  visual_rect_ = new_visual_rect;
}

void CaretDisplayItemClient::PaintCaret(
    GraphicsContext& context,
    const LayoutPoint& paint_offset,
    DisplayItem::Type display_item_type) const {
  if (DrawingRecorder::UseCachedDrawingIfPossible(context, *this,
                                                  display_item_type))
    return;

  LayoutRect drawing_rect = local_rect_;
  drawing_rect.MoveBy(paint_offset);

  DrawingRecorder recorder(context, *this, display_item_type);
  IntRect paint_rect = PixelSnappedIntRect(drawing_rect);
  context.FillRect(paint_rect, color_);
}

String CaretDisplayItemClient::DebugName() const {
  return "Caret";
}

LayoutRect CaretDisplayItemClient::VisualRect() const {
  return visual_rect_;
}

}  // namespace blink