import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

layout/generic/nsTextFrameUtils.h

@@ -0,0 +1,178 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * 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 NSTEXTFRAMEUTILS_H_
+#define NSTEXTFRAMEUTILS_H_
+
+#include "gfxSkipChars.h"
+#include "nsBidiUtils.h"
+#include "nsUnicodeProperties.h"
+
+class nsIContent;
+struct nsStyleText;
+
+#define BIG_TEXT_NODE_SIZE 4096
+
+#define CH_NBSP   160
+#define CH_SHY    173
+#define CH_CJKSP  12288 // U+3000 IDEOGRAPHIC SPACE (CJK Full-Width Space)
+
+class nsTextFrameUtils {
+public:
+  // These constants are used as textrun flags for textframe textruns.
+  enum {
+    // The following flags are set by TransformText
+
+    // the text has at least one untransformed tab character
+    TEXT_HAS_TAB             = 0x010000,
+    // the original text has at least one soft hyphen character
+    TEXT_HAS_SHY             = 0x020000,
+    TEXT_WAS_TRANSFORMED     = 0x040000,
+    TEXT_UNUSED_FLAG         = 0x080000,
+
+    // The following flags are set by nsTextFrame
+
+    TEXT_IS_SIMPLE_FLOW      = 0x100000,
+    TEXT_INCOMING_WHITESPACE = 0x200000,
+    TEXT_TRAILING_WHITESPACE = 0x400000,
+    TEXT_COMPRESSED_LEADING_WHITESPACE = 0x800000,
+    TEXT_NO_BREAKS           = 0x1000000,
+    TEXT_IS_TRANSFORMED      = 0x2000000,
+    // This gets set if there's a break opportunity at the end of the textrun.
+    // We normally don't use this break opportunity because the following text
+    // will have a break opportunity at the start, but it's useful for line
+    // layout to know about it in case the following content is not text
+    TEXT_HAS_TRAILING_BREAK  = 0x4000000,
+
+    // This is set if the textrun was created for a textframe whose
+    // NS_FRAME_IS_IN_SINGLE_CHAR_MI flag is set.  This occurs if the textframe
+    // belongs to a MathML <mi> element whose embedded text consists of a
+    // single character.
+    TEXT_IS_SINGLE_CHAR_MI   = 0x8000000,
+
+    // This is set if the text run might be observing for glyph changes.
+    TEXT_MIGHT_HAVE_GLYPH_CHANGES = 0x10000000,
+
+    // The following are defined by gfxTextRunWordCache rather than here,
+    // so that it also has access to the _INCOMING flag
+    // TEXT_TRAILING_ARABICCHAR
+    // TEXT_INCOMING_ARABICCHAR
+
+    // This is defined in gfxTextRunFactory to allow access in gfxFont.
+    // TEXT_USE_MATH_SCRIPT
+  };
+
+  // These constants are used in TransformText to represent context information
+  // from previous textruns.
+  enum {
+    INCOMING_NONE       = 0,
+    INCOMING_WHITESPACE = 1,
+    INCOMING_ARABICCHAR = 2
+  };
+
+  /**
+   * Returns true if aChars/aLength are something that make a space
+   * character not be whitespace when they follow the space character
+   * (combining mark or join control, ignoring intervening direction
+   * controls).
+   */
+  static bool
+  IsSpaceCombiningSequenceTail(const char16_t* aChars, int32_t aLength) {
+    return aLength > 0 &&
+      (mozilla::unicode::IsClusterExtender(aChars[0]) ||
+       (IsBidiControl(aChars[0]) &&
+        IsSpaceCombiningSequenceTail(aChars + 1, aLength - 1)
+       )
+      );
+  }
+
+  enum CompressionMode {
+    COMPRESS_NONE,
+    COMPRESS_WHITESPACE,
+    COMPRESS_WHITESPACE_NEWLINE,
+    COMPRESS_NONE_TRANSFORM_TO_SPACE
+  };
+
+  /**
+   * Create a text run from a run of Unicode text. The text may have whitespace
+   * compressed. A preformatted tab is sent to the text run as a single space.
+   * (Tab spacing must be performed by textframe later.) Certain other
+   * characters are discarded.
+   * 
+   * @param aCompressWhitespace control what is compressed to a
+   * single space character: no compression, compress spaces (not followed
+   * by combining mark) and tabs, compress those plus newlines, or
+   * no compression except newlines are discarded.
+   * @param aIncomingFlags a flag indicating whether there was whitespace
+   * or an Arabic character preceding this text. We set it to indicate if
+   * there's an Arabic character or whitespace preceding the end of this text.
+   */
+  static char16_t* TransformText(const char16_t* aText, uint32_t aLength,
+                                  char16_t* aOutput,
+                                  CompressionMode aCompression,
+                                  uint8_t * aIncomingFlags,
+                                  gfxSkipChars* aSkipChars,
+                                  uint32_t* aAnalysisFlags);
+
+  static uint8_t* TransformText(const uint8_t* aText, uint32_t aLength,
+                                uint8_t* aOutput,
+                                CompressionMode aCompression,
+                                uint8_t * aIncomingFlags,
+                                gfxSkipChars* aSkipChars,
+                                uint32_t* aAnalysisFlags);
+
+  static void
+  AppendLineBreakOffset(nsTArray<uint32_t>* aArray, uint32_t aOffset)
+  {
+    if (aArray->Length() > 0 && (*aArray)[aArray->Length() - 1] == aOffset)
+      return;
+    aArray->AppendElement(aOffset);
+  }
+
+  static uint32_t
+  ComputeApproximateLengthWithWhitespaceCompression(nsIContent *aContent,
+                                                    const nsStyleText
+                                                      *aStyleText);
+};
+
+class nsSkipCharsRunIterator {
+public:
+  enum LengthMode {
+    LENGTH_UNSKIPPED_ONLY   = false,
+    LENGTH_INCLUDES_SKIPPED = true
+  };
+  nsSkipCharsRunIterator(const gfxSkipCharsIterator& aStart,
+      LengthMode aLengthIncludesSkipped, uint32_t aLength)
+    : mIterator(aStart), mRemainingLength(aLength), mRunLength(0),
+      mVisitSkipped(false),
+      mLengthIncludesSkipped(aLengthIncludesSkipped) {
+  }
+  void SetVisitSkipped() { mVisitSkipped = true; }
+  void SetOriginalOffset(int32_t aOffset) {
+    mIterator.SetOriginalOffset(aOffset);
+  }
+  void SetSkippedOffset(uint32_t aOffset) {
+    mIterator.SetSkippedOffset(aOffset);
+  }
+
+  // guaranteed to return only positive-length runs
+  bool NextRun();
+  bool IsSkipped() const { return mSkipped; }
+  // Always returns something > 0
+  int32_t GetRunLength() const { return mRunLength; }
+  const gfxSkipCharsIterator& GetPos() const { return mIterator; }
+  int32_t GetOriginalOffset() const { return mIterator.GetOriginalOffset(); }
+  uint32_t GetSkippedOffset() const { return mIterator.GetSkippedOffset(); }
+
+private:
+  gfxSkipCharsIterator mIterator;
+  int32_t              mRemainingLength;
+  int32_t              mRunLength;
+  bool                 mSkipped;
+  bool                 mVisitSkipped;
+  bool                 mLengthIncludesSkipped;
+};
+
+#endif /*NSTEXTFRAMEUTILS_H_*/