DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (3cc34f31408f)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412
/* -*- 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"
#include "nsISelectionController.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() {}

    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(); }
    uint32_t EndOffset() const { return mEnd.Offset(); }
    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:
    nsINode* IsValidBoundary(nsINode* aNode) const;
    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.
  nsresult HandleQueryContentEvent(WidgetQueryContentEvent* aEvent);

  // eQuerySelectedText event handler
  nsresult OnQuerySelectedText(WidgetQueryContentEvent* aEvent);
  // eQueryTextContent event handler
  nsresult OnQueryTextContent(WidgetQueryContentEvent* aEvent);
  // eQueryCaretRect event handler
  nsresult OnQueryCaretRect(WidgetQueryContentEvent* aEvent);
  // eQueryTextRect event handler
  nsresult OnQueryTextRect(WidgetQueryContentEvent* aEvent);
  // eQueryTextRectArray event handler
  nsresult OnQueryTextRectArray(WidgetQueryContentEvent* aEvent);
  // eQueryEditorRect event handler
  nsresult OnQueryEditorRect(WidgetQueryContentEvent* aEvent);
  // eQueryContentState event handler
  nsresult OnQueryContentState(WidgetQueryContentEvent* aEvent);
  // eQuerySelectionAsTransferable event handler
  nsresult OnQuerySelectionAsTransferable(WidgetQueryContentEvent* aEvent);
  // eQueryCharacterAtPoint event handler
  nsresult OnQueryCharacterAtPoint(WidgetQueryContentEvent* aEvent);
  // eQueryDOMWidgetHittest event handler
  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;

  nsresult Init(WidgetQueryContentEvent* aEvent);
  nsresult Init(WidgetSelectionEvent* aEvent);

  nsresult InitBasic(bool aRequireFlush = true);
  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.
   */
  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() : RangeBoundary() {}

    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();
  // Returns true if the content is a plugin host.
  bool IsPlugin(nsIContent* aContent);
  // 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_