The Tor Browser / file revision

 /* -*- 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"

 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

     // 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.

    * For now, this is true if and only if aChars starts with a ZWJ. (This

    * is what Uniscribe assumes.)

    */

   static bool

   IsSpaceCombiningSequenceTail(const char16_t* aChars, int32_t aLength) {

     return aLength > 0 && aChars[0] == 0x200D; // ZWJ

   }

   enum CompressionMode {

     COMPRESS_NONE,

     COMPRESS_WHITESPACE,

     COMPRESS_WHITESPACE_NEWLINE,

     DISCARD_NEWLINE

   };

   /**

    * 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_*/