Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 587 insertions, 0 deletions

diff --git a/layout/base/nsBidiPresUtils.h b/layout/base/nsBidiPresUtils.h
new file mode 100644
index 0000000000..c369a06f2d
--- /dev/null
+++ b/layout/base/nsBidiPresUtils.h
@@ -0,0 +1,587 @@
+/* -*- 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 nsBidiPresUtils_h___
+#define nsBidiPresUtils_h___
+
+#include "gfxContext.h"
+#include "mozilla/intl/BidiClass.h"
+#include "mozilla/intl/BidiEmbeddingLevel.h"
+#include "nsBidiUtils.h"
+#include "nsHashKeys.h"
+#include "nsCoord.h"
+#include "nsTArray.h"
+#include "nsLineBox.h"
+
+#ifdef DrawText
+#  undef DrawText
+#endif
+
+struct BidiParagraphData;
+struct BidiLineData;
+class gfxContext;
+class nsFontMetrics;
+class nsIFrame;
+class nsBlockFrame;
+class nsPresContext;
+struct nsSize;
+template <class T>
+class nsTHashtable;
+namespace mozilla {
+namespace intl {
+class Bidi;
+}
+class ComputedStyle;
+class LogicalMargin;
+class WritingMode;
+}  // namespace mozilla
+
+/**
+ * A structure representing some continuation state for each frame on the line,
+ * used to determine the first and the last continuation frame for each
+ * continuation chain on the line.
+ */
+struct nsFrameContinuationState : public nsVoidPtrHashKey {
+  explicit nsFrameContinuationState(const void* aFrame)
+      : nsVoidPtrHashKey(aFrame) {}
+
+  /**
+   * The first visual frame in the continuation chain containing this frame, or
+   * nullptr if this frame is the first visual frame in the chain.
+   */
+  nsIFrame* mFirstVisualFrame{nullptr};
+
+  /**
+   * The number of frames in the continuation chain containing this frame, if
+   * this frame is the first visual frame of the chain, or 0 otherwise.
+   */
+  uint32_t mFrameCount{0};
+
+  /**
+   * TRUE if this frame is the first visual frame of its continuation chain on
+   * this line and the chain has some frames on the previous lines.
+   */
+  bool mHasContOnPrevLines{false};
+
+  /**
+   * TRUE if this frame is the first visual frame of its continuation chain on
+   * this line and the chain has some frames left for next lines.
+   */
+  bool mHasContOnNextLines{false};
+};
+
+// A table of nsFrameContinuationState objects.
+//
+// This state is used between calls to nsBidiPresUtils::IsFirstOrLast.
+struct nsContinuationStates {
+  static constexpr size_t kArrayMax = 32;
+
+  // We use the array to gather up all the continuation state objects.  If in
+  // the end there are more than kArrayMax of them, we convert it to a hash
+  // table for faster lookup.
+  bool mUseTable = false;
+  AutoTArray<nsFrameContinuationState, kArrayMax> mValues;
+  nsTHashtable<nsFrameContinuationState> mTable;
+
+  void Insert(nsIFrame* aFrame) {
+    if (MOZ_UNLIKELY(mUseTable)) {
+      mTable.PutEntry(aFrame);
+      return;
+    }
+    if (MOZ_LIKELY(mValues.Length() < kArrayMax)) {
+      mValues.AppendElement(aFrame);
+      return;
+    }
+    for (const auto& entry : mValues) {
+      mTable.PutEntry(entry.GetKey());
+    }
+    mTable.PutEntry(aFrame);
+    mValues.Clear();
+    mUseTable = true;
+  }
+
+  nsFrameContinuationState* Get(nsIFrame* aFrame) {
+    MOZ_ASSERT(mValues.IsEmpty() != mTable.IsEmpty(),
+               "expect entries to either be in mValues or in mTable");
+    if (mUseTable) {
+      return mTable.GetEntry(aFrame);
+    }
+    for (size_t i = 0, len = mValues.Length(); i != len; ++i) {
+      if (mValues[i].GetKey() == aFrame) {
+        return &mValues[i];
+      }
+    }
+    return nullptr;
+  }
+};
+
+/**
+ * A structure representing a logical position which should be resolved
+ * into its visual position during BiDi processing.
+ */
+struct nsBidiPositionResolve {
+  // [in] Logical index within string.
+  int32_t logicalIndex;
+  // [out] Visual index within string.
+  // If the logical position was not found, set to kNotFound.
+  int32_t visualIndex;
+  // [out] Visual position of the character, from the left (on the X axis), in
+  // twips. Eessentially, this is the X position (relative to the rendering
+  // context) where the text was drawn + the font metric of the visual string to
+  // the left of the given logical position. If the logical position was not
+  // found, set to kNotFound.
+  int32_t visualLeftTwips;
+  // [out] Visual width of the character, in twips.
+  // If the logical position was not found, set to kNotFound.
+  int32_t visualWidth;
+};
+
+class nsBidiPresUtils {
+ public:
+  typedef mozilla::gfx::DrawTarget DrawTarget;
+
+  nsBidiPresUtils();
+  ~nsBidiPresUtils();
+
+  /**
+   * Interface for the processor used by ProcessText. Used by process text to
+   * collect information about the width of subruns and to notify where each
+   * subrun should be rendered.
+   */
+  class BidiProcessor {
+   public:
+    virtual ~BidiProcessor() = default;
+
+    /**
+     * Sets the current text with the given length and the given direction.
+     *
+     * @remark The reason that the function gives a string instead of an index
+     *  is that ProcessText copies and modifies the string passed to it, so
+     *  passing an index would be impossible.
+     *
+     * @param aText The string of text.
+     * @param aLength The length of the string of text.
+     * @param aDirection The direction of the text. The string will never have
+     *  mixed direction.
+     */
+    virtual void SetText(const char16_t* aText, int32_t aLength,
+                         mozilla::intl::BidiDirection aDirection) = 0;
+
+    /**
+     * Returns the measured width of the text given in SetText. If SetText was
+     * not called with valid parameters, the result of this call is undefined.
+     * This call is guaranteed to only be called once between SetText calls.
+     * Will be invoked before DrawText.
+     */
+    virtual nscoord GetWidth() = 0;
+
+    /**
+     * Draws the text given in SetText to a rendering context. If SetText was
+     * not called with valid parameters, the result of this call is undefined.
+     * This call is guaranteed to only be called once between SetText calls.
+     *
+     * @param aXOffset The offset of the left side of the substring to be drawn
+     *  from the beginning of the overall string passed to ProcessText.
+     */
+    virtual void DrawText(nscoord aXOffset) = 0;
+  };
+
+  /**
+   * Make Bidi engine calculate the embedding levels of the frames that are
+   * descendants of a given block frame.
+   *
+   * @param aBlockFrame          The block frame
+   *
+   *  @lina 06/18/2000
+   */
+  static nsresult Resolve(nsBlockFrame* aBlockFrame);
+  static nsresult ResolveParagraph(BidiParagraphData* aBpd);
+  static void ResolveParagraphWithinBlock(BidiParagraphData* aBpd);
+
+  /**
+   * Reorder this line using Bidi engine.
+   * Update frame array, following the new visual sequence.
+   *
+   * @return total inline size
+   *
+   * @lina 05/02/2000
+   */
+  static nscoord ReorderFrames(nsIFrame* aFirstFrameOnLine,
+                               int32_t aNumFramesOnLine,
+                               mozilla::WritingMode aLineWM,
+                               const nsSize& aContainerSize, nscoord aStart);
+
+  /**
+   * Format Unicode text, taking into account bidi capabilities
+   * of the platform. The formatting includes: reordering, Arabic shaping,
+   * symmetric and numeric swapping, removing control characters.
+   *
+   * @lina 06/18/2000
+   */
+  static nsresult FormatUnicodeText(nsPresContext* aPresContext,
+                                    char16_t* aText, int32_t& aTextLength,
+                                    mozilla::intl::BidiClass aBidiClass);
+
+  /**
+   * Reorder plain text using the Unicode Bidi algorithm and send it to
+   * a rendering context for rendering.
+   *
+   * @param[in] aText  the string to be rendered (in logical order)
+   * @param aLength the number of characters in the string
+   * @param aBaseLevel the base embedding level of the string
+   * @param aPresContext the presentation context
+   * @param aRenderingContext the rendering context to render to
+   * @param aTextRunConstructionContext the rendering context to be used to
+   * construct the textrun (affects font hinting)
+   * @param aX the x-coordinate to render the string
+   * @param aY the y-coordinate to render the string
+   * @param[in,out] aPosResolve array of logical positions to resolve into
+   * visual positions; can be nullptr if this functionality is not required
+   * @param aPosResolveCount number of items in the aPosResolve array
+   */
+  static nsresult RenderText(const char16_t* aText, int32_t aLength,
+                             mozilla::intl::BidiEmbeddingLevel aBaseLevel,
+                             nsPresContext* aPresContext,
+                             gfxContext& aRenderingContext,
+                             DrawTarget* aTextRunConstructionDrawTarget,
+                             nsFontMetrics& aFontMetrics, nscoord aX,
+                             nscoord aY,
+                             nsBidiPositionResolve* aPosResolve = nullptr,
+                             int32_t aPosResolveCount = 0) {
+    return ProcessTextForRenderingContext(
+        aText, aLength, aBaseLevel, aPresContext, aRenderingContext,
+        aTextRunConstructionDrawTarget, aFontMetrics, MODE_DRAW, aX, aY,
+        aPosResolve, aPosResolveCount, nullptr);
+  }
+
+  static nscoord MeasureTextWidth(const char16_t* aText, int32_t aLength,
+                                  mozilla::intl::BidiEmbeddingLevel aBaseLevel,
+                                  nsPresContext* aPresContext,
+                                  gfxContext& aRenderingContext,
+                                  nsFontMetrics& aFontMetrics) {
+    nscoord length;
+    nsresult rv = ProcessTextForRenderingContext(
+        aText, aLength, aBaseLevel, aPresContext, aRenderingContext,
+        aRenderingContext.GetDrawTarget(), aFontMetrics, MODE_MEASURE, 0, 0,
+        nullptr, 0, &length);
+    return NS_SUCCEEDED(rv) ? length : 0;
+  }
+
+  /**
+   * Check if a line is reordered, i.e., if the child frames are not
+   * all laid out left-to-right.
+   * @param aFirstFrameOnLine : first frame of the line to be tested
+   * @param aNumFramesOnLine : number of frames on this line
+   * @param[out] aLeftMost : leftmost frame on this line
+   * @param[out] aRightMost : rightmost frame on this line
+   */
+  static bool CheckLineOrder(nsIFrame* aFirstFrameOnLine,
+                             int32_t aNumFramesOnLine, nsIFrame** aLeftmost,
+                             nsIFrame** aRightmost);
+
+  /**
+   * Get the frame to the right of the given frame, on the same line.
+   * @param aFrame : We're looking for the frame to the right of this frame.
+   *                 If null, return the leftmost frame on the line.
+   * @param aFirstFrameOnLine : first frame of the line to be tested
+   * @param aNumFramesOnLine : number of frames on this line
+   */
+  static nsIFrame* GetFrameToRightOf(const nsIFrame* aFrame,
+                                     nsIFrame* aFirstFrameOnLine,
+                                     int32_t aNumFramesOnLine);
+
+  /**
+   * Get the frame to the left of the given frame, on the same line.
+   * @param aFrame : We're looking for the frame to the left of this frame.
+   *                 If null, return the rightmost frame on the line.
+   * @param aFirstFrameOnLine : first frame of the line to be tested
+   * @param aNumFramesOnLine : number of frames on this line
+   */
+  static nsIFrame* GetFrameToLeftOf(const nsIFrame* aFrame,
+                                    nsIFrame* aFirstFrameOnLine,
+                                    int32_t aNumFramesOnLine);
+
+  static nsIFrame* GetFirstLeaf(nsIFrame* aFrame);
+
+  /**
+   * Get the bidi data of the given (inline) frame.
+   */
+  static mozilla::FrameBidiData GetFrameBidiData(nsIFrame* aFrame);
+
+  /**
+   * Get the bidi embedding level of the given (inline) frame.
+   */
+  static mozilla::intl::BidiEmbeddingLevel GetFrameEmbeddingLevel(
+      nsIFrame* aFrame);
+
+  /**
+   * Get the bidi base level of the given (inline) frame.
+   */
+  static mozilla::intl::BidiEmbeddingLevel GetFrameBaseLevel(
+      const nsIFrame* aFrame);
+
+  /**
+   * Get a mozilla::intl::BidiDirection representing the direction implied by
+   * the bidi base level of the frame.
+   * @return mozilla::intl::BidiDirection
+   */
+  static mozilla::intl::BidiDirection ParagraphDirection(
+      const nsIFrame* aFrame) {
+    return GetFrameBaseLevel(aFrame).Direction();
+  }
+
+  /**
+   * Get a mozilla::intl::BidiDirection representing the direction implied by
+   * the bidi embedding level of the frame.
+   * @return mozilla::intl::BidiDirection
+   */
+  static mozilla::intl::BidiDirection FrameDirection(nsIFrame* aFrame) {
+    return GetFrameEmbeddingLevel(aFrame).Direction();
+  }
+
+  static bool IsFrameInParagraphDirection(nsIFrame* aFrame) {
+    return ParagraphDirection(aFrame) == FrameDirection(aFrame);
+  }
+
+  // This is faster than nsBidiPresUtils::IsFrameInParagraphDirection,
+  // because it uses the frame pointer passed in without drilling down to
+  // the leaf frame.
+  static bool IsReversedDirectionFrame(const nsIFrame* aFrame) {
+    mozilla::FrameBidiData bidiData = aFrame->GetBidiData();
+    return !bidiData.embeddingLevel.IsSameDirection(bidiData.baseLevel);
+  }
+
+  enum Mode { MODE_DRAW, MODE_MEASURE };
+
+  /**
+   * Reorder plain text using the Unicode Bidi algorithm and send it to
+   * a processor for rendering or measuring
+   *
+   * @param[in] aText  the string to be processed (in logical order)
+   * @param aLength the number of characters in the string
+   * @param aBaseLevel the base embedding level of the string
+   * @param aPresContext the presentation context
+   * @param aprocessor the bidi processor
+   * @param aMode the operation to process
+   *  MODE_DRAW - invokes DrawText on the processor for each substring
+   *  MODE_MEASURE - does not invoke DrawText on the processor
+   *  Note that the string is always measured, regardless of mode
+   * @param[in,out] aPosResolve array of logical positions to resolve into
+   *  visual positions; can be nullptr if this functionality is not required
+   * @param aPosResolveCount number of items in the aPosResolve array
+   * @param[out] aWidth Pointer to where the width will be stored (may be null)
+   */
+  static nsresult ProcessText(const char16_t* aText, size_t aLength,
+                              mozilla::intl::BidiEmbeddingLevel aBaseLevel,
+                              nsPresContext* aPresContext,
+                              BidiProcessor& aprocessor, Mode aMode,
+                              nsBidiPositionResolve* aPosResolve,
+                              int32_t aPosResolveCount, nscoord* aWidth,
+                              mozilla::intl::Bidi& aBidiEngine);
+
+  /**
+   * Use style attributes to determine the base paragraph level to pass to the
+   * bidi algorithm.
+   *
+   * If |unicode-bidi| is set to "[-moz-]plaintext", returns
+   * BidiEmbeddingLevel::DefaultLTR, in other words the direction is determined
+   * from the first strong character in the text according to rules P2 and P3 of
+   * the bidi algorithm, or LTR if there is no strong character.
+   *
+   * Otherwise returns BidiEmbeddingLevel::LTR or BidiEmbeddingLevel::RTL
+   * depending on the value of |direction|
+   */
+  static mozilla::intl::BidiEmbeddingLevel BidiLevelFromStyle(
+      mozilla::ComputedStyle* aComputedStyle);
+
+ private:
+  static nsresult ProcessTextForRenderingContext(
+      const char16_t* aText, int32_t aLength,
+      mozilla::intl::BidiEmbeddingLevel aBaseLevel, nsPresContext* aPresContext,
+      gfxContext& aRenderingContext, DrawTarget* aTextRunConstructionDrawTarget,
+      nsFontMetrics& aFontMetrics, Mode aMode,
+      nscoord aX,                         // DRAW only
+      nscoord aY,                         // DRAW only
+      nsBidiPositionResolve* aPosResolve, /* may be null */
+      int32_t aPosResolveCount, nscoord* aWidth /* may be null */);
+
+  /**
+   * Simplified form of ProcessText body, used when aText is a single Unicode
+   * character (one UTF-16 codepoint, or a surrogate pair), or a run that is
+   * known to have no bidi content.
+   */
+  static void ProcessSimpleRun(const char16_t* aText, size_t aLength,
+                               mozilla::intl::BidiEmbeddingLevel aBaseLevel,
+                               nsPresContext* aPresContext,
+                               BidiProcessor& aprocessor, Mode aMode,
+                               nsBidiPositionResolve* aPosResolve,
+                               int32_t aPosResolveCount, nscoord* aWidth);
+
+  /**
+   * Traverse the child frames of the block element and:
+   *  Set up an array of the frames in logical order
+   *  Create a string containing the text content of all the frames
+   *  If we encounter content that requires us to split the element into more
+   *  than one paragraph for bidi resolution, resolve the paragraph up to that
+   *  point.
+   */
+  static void TraverseFrames(nsIFrame* aCurrentFrame, BidiParagraphData* aBpd);
+
+  /**
+   * Perform a recursive "pre-traversal" of the child frames of a block or
+   * inline container frame, to determine whether full bidi resolution is
+   * actually needed.
+   * This explores the same frames as TraverseFrames (above), but is less
+   * expensive and may allow us to avoid performing the full TraverseFrames
+   * operation.
+   * @param   aFirstChild  frame to start traversal from
+   * @param[in/out]  aCurrContent  the content node that we've most recently
+   *          scanned for RTL characters (so that when descendant frames refer
+   *          to the same content, we can avoid repeatedly scanning it).
+   * @return  true if it finds that bidi is (or may be) required,
+   *          false if no potentially-bidi content is present.
+   */
+  static bool ChildListMayRequireBidi(nsIFrame* aFirstChild,
+                                      nsIContent** aCurrContent);
+
+  /**
+   * Position ruby content frames (ruby base/text frame).
+   * Called from RepositionRubyFrame.
+   */
+  static void RepositionRubyContentFrame(
+      nsIFrame* aFrame, mozilla::WritingMode aFrameWM,
+      const mozilla::LogicalMargin& aBorderPadding);
+
+  /*
+   * Position ruby frames. Called from RepositionFrame.
+   */
+  static nscoord RepositionRubyFrame(
+      nsIFrame* aFrame, nsContinuationStates* aContinuationStates,
+      const mozilla::WritingMode aContainerWM,
+      const mozilla::LogicalMargin& aBorderPadding);
+
+  /*
+   * Position aFrame and its descendants to their visual places. Also if aFrame
+   * is not leaf, resize it to embrace its children.
+   *
+   * @param aFrame               The frame which itself and its children are
+   *                             going to be repositioned
+   * @param aIsEvenLevel         TRUE means the embedding level of this frame
+   *                             is even (LTR)
+   * @param aStartOrEnd          The distance to the start or the end of aFrame
+   *                             without considering its inline margin. If the
+   *                             container is reordering frames in reverse
+   *                             direction, it's the distance to the end,
+   *                             otherwise, it's the distance to the start.
+   * @param aContinuationStates  A map from nsIFrame* to
+   *                             nsFrameContinuationState
+   * @return                     The isize aFrame takes, including margins.
+   */
+  static nscoord RepositionFrame(nsIFrame* aFrame, bool aIsEvenLevel,
+                                 nscoord aStartOrEnd,
+                                 nsContinuationStates* aContinuationStates,
+                                 mozilla::WritingMode aContainerWM,
+                                 bool aContainerReverseOrder,
+                                 const nsSize& aContainerSize);
+
+  /*
+   * Initialize the continuation state(nsFrameContinuationState) to
+   * (nullptr, 0) for aFrame and its descendants.
+   *
+   * @param aFrame               The frame which itself and its descendants will
+   *                             be initialized
+   * @param aContinuationStates  A map from nsIFrame* to
+   *                             nsFrameContinuationState
+   */
+  static void InitContinuationStates(nsIFrame* aFrame,
+                                     nsContinuationStates* aContinuationStates);
+
+  /*
+   * Determine if aFrame is first or last, and set aIsFirst and
+   * aIsLast values. Also set continuation states of
+   * aContinuationStates.
+   *
+   * A frame is first if it's the first appearance of its continuation
+   * chain on the line and the chain is on its first line.
+   * A frame is last if it's the last appearance of its continuation
+   * chain on the line and the chain is on its last line.
+   *
+   * N.B: "First appearance" and "Last appearance" in the previous
+   * paragraph refer to the frame's inline direction, not necessarily
+   * the line's.
+   *
+   * @param aContinuationStates        A map from nsIFrame* to
+   *                                    nsFrameContinuationState
+   * @param[in] aSpanDirMatchesLineDir TRUE means that the inline
+   *                                    direction of aFrame is the same
+   *                                    as its container
+   * @param[out] aIsFirst              TRUE means aFrame is first frame
+   *                                    or continuation
+   * @param[out] aIsLast               TRUE means aFrame is last frame
+   *                                    or continuation
+   */
+  static void IsFirstOrLast(nsIFrame* aFrame,
+                            nsContinuationStates* aContinuationStates,
+                            bool aSpanInLineOrder /* in */,
+                            bool& aIsFirst /* out */, bool& aIsLast /* out */);
+
+  /**
+   *  Adjust frame positions following their visual order
+   *
+   *  @param aFirstChild the first kid
+   *  @return total inline size
+   *
+   *  @lina 04/11/2000
+   */
+  static nscoord RepositionInlineFrames(BidiLineData* aBld,
+                                        mozilla::WritingMode aLineWM,
+                                        const nsSize& aContainerSize,
+                                        nscoord aStart);
+
+  /**
+   * Helper method for Resolve()
+   * Truncate a text frame to the end of a single-directional run and possibly
+   * create a continuation frame for the remainder of its content.
+   *
+   * @param aFrame       the original frame
+   * @param aLine        the line box containing aFrame
+   * @param aNewFrame    [OUT] the new frame that was created
+   * @param aStart       [IN] the start of the content mapped by aFrame (and
+   *                          any fluid continuations)
+   * @param aEnd         [IN] the offset of the end of the single-directional
+   *                          text run.
+   * @see Resolve()
+   * @see RemoveBidiContinuation()
+   */
+  static inline void EnsureBidiContinuation(nsIFrame* aFrame,
+                                            const nsLineList::iterator aLine,
+                                            nsIFrame** aNewFrame,
+                                            int32_t aStart, int32_t aEnd);
+
+  /**
+   * Helper method for Resolve()
+   * Convert one or more bidi continuation frames created in a previous reflow
+   * by EnsureBidiContinuation() into fluid continuations.
+   * @param aFrame       the frame whose continuations are to be removed
+   * @param aFirstIndex  index of aFrame in mLogicalFrames
+   * @param aLastIndex   index of the last frame to be removed
+   *
+   * @see Resolve()
+   * @see EnsureBidiContinuation()
+   */
+  static void RemoveBidiContinuation(BidiParagraphData* aBpd, nsIFrame* aFrame,
+                                     int32_t aFirstIndex, int32_t aLastIndex);
+
+  static void CalculateBidiClass(const char16_t* aText, int32_t& aOffset,
+                                 int32_t aBidiClassLimit, int32_t& aRunLimit,
+                                 int32_t& aRunLength, int32_t& aRunCount,
+                                 mozilla::intl::BidiClass& aBidiClass,
+                                 mozilla::intl::BidiClass& aPrevBidiClass);
+
+  static void StripBidiControlCharacters(char16_t* aText, int32_t& aTextLength);
+};
+
+#endif /* nsBidiPresUtils_h___ */