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Diffstat (limited to 'layout/generic/nsTextFrameUtils.cpp')
| -rw-r--r-- | layout/generic/nsTextFrameUtils.cpp | 304 |
1 files changed, 304 insertions, 0 deletions
diff --git a/layout/generic/nsTextFrameUtils.cpp b/layout/generic/nsTextFrameUtils.cpp new file mode 100644 index 000000000..d07400f2b --- /dev/null +++ b/layout/generic/nsTextFrameUtils.cpp @@ -0,0 +1,304 @@ +/* -*- 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/. */ + +#include "nsTextFrameUtils.h" + +#include "nsBidiUtils.h" +#include "nsCharTraits.h" +#include "nsIContent.h" +#include "nsStyleStruct.h" +#include "nsTextFragment.h" +#include "nsUnicharUtils.h" +#include <algorithm> + +static bool IsDiscardable(char16_t ch, uint32_t* aFlags) +{ + // Unlike IS_DISCARDABLE, we don't discard \r. \r will be ignored by gfxTextRun + // and discarding it would force us to copy text in many cases of preformatted + // text containing \r\n. + if (ch == CH_SHY) { + *aFlags |= nsTextFrameUtils::TEXT_HAS_SHY; + return true; + } + return IsBidiControl(ch); +} + +static bool IsDiscardable(uint8_t ch, uint32_t* aFlags) +{ + if (ch == CH_SHY) { + *aFlags |= nsTextFrameUtils::TEXT_HAS_SHY; + return true; + } + return false; +} + +char16_t* +nsTextFrameUtils::TransformText(const char16_t* aText, uint32_t aLength, + char16_t* aOutput, + CompressionMode aCompression, + uint8_t* aIncomingFlags, + gfxSkipChars* aSkipChars, + uint32_t* aAnalysisFlags) +{ + uint32_t flags = 0; + char16_t* outputStart = aOutput; + + bool lastCharArabic = false; + + if (aCompression == COMPRESS_NONE || + aCompression == COMPRESS_NONE_TRANSFORM_TO_SPACE) { + // Skip discardables. + uint32_t i; + for (i = 0; i < aLength; ++i) { + char16_t ch = aText[i]; + if (IsDiscardable(ch, &flags)) { + aSkipChars->SkipChar(); + } else { + aSkipChars->KeepChar(); + if (ch > ' ') { + lastCharArabic = IS_ARABIC_CHAR(ch); + } else if (aCompression == COMPRESS_NONE_TRANSFORM_TO_SPACE) { + if (ch == '\t' || ch == '\n') { + ch = ' '; + flags |= TEXT_WAS_TRANSFORMED; + } + } else { + // aCompression == COMPRESS_NONE + if (ch == '\t') { + flags |= TEXT_HAS_TAB; + } + } + *aOutput++ = ch; + } + } + if (lastCharArabic) { + *aIncomingFlags |= INCOMING_ARABICCHAR; + } else { + *aIncomingFlags &= ~INCOMING_ARABICCHAR; + } + *aIncomingFlags &= ~INCOMING_WHITESPACE; + } else { + bool inWhitespace = (*aIncomingFlags & INCOMING_WHITESPACE) != 0; + uint32_t i; + for (i = 0; i < aLength; ++i) { + char16_t ch = aText[i]; + bool nowInWhitespace; + if (ch == ' ' && + (i + 1 >= aLength || + !IsSpaceCombiningSequenceTail(&aText[i + 1], aLength - (i + 1)))) { + nowInWhitespace = true; + } else if (ch == '\n' && aCompression == COMPRESS_WHITESPACE_NEWLINE) { + if ((i > 0 && IS_ZERO_WIDTH_SPACE(aText[i - 1])) || + (i + 1 < aLength && IS_ZERO_WIDTH_SPACE(aText[i + 1]))) { + aSkipChars->SkipChar(); + continue; + } + uint32_t ucs4before; + uint32_t ucs4after; + if (i > 1 && + NS_IS_LOW_SURROGATE(aText[i - 1]) && + NS_IS_HIGH_SURROGATE(aText[i - 2])) { + ucs4before = SURROGATE_TO_UCS4(aText[i - 2], aText[i - 1]); + } else if (i > 0) { + ucs4before = aText[i - 1]; + } + if (i + 2 < aLength && + NS_IS_HIGH_SURROGATE(aText[i + 1]) && + NS_IS_LOW_SURROGATE(aText[i + 2])) { + ucs4after = SURROGATE_TO_UCS4(aText[i + 1], aText[i + 2]); + } else if (i + 1 < aLength) { + ucs4after = aText[i + 1]; + } + if (i > 0 && IsSegmentBreakSkipChar(ucs4before) && + i + 1 < aLength && IsSegmentBreakSkipChar(ucs4after)) { + // Discard newlines between characters that have F, W, or H + // EastAsianWidth property and neither side is Hangul. + aSkipChars->SkipChar(); + continue; + } + nowInWhitespace = true; + } else { + nowInWhitespace = ch == '\t'; + } + + if (!nowInWhitespace) { + if (IsDiscardable(ch, &flags)) { + aSkipChars->SkipChar(); + nowInWhitespace = inWhitespace; + } else { + *aOutput++ = ch; + aSkipChars->KeepChar(); + lastCharArabic = IS_ARABIC_CHAR(ch); + } + } else { + if (inWhitespace) { + aSkipChars->SkipChar(); + } else { + if (ch != ' ') { + flags |= TEXT_WAS_TRANSFORMED; + } + *aOutput++ = ' '; + aSkipChars->KeepChar(); + } + } + inWhitespace = nowInWhitespace; + } + if (lastCharArabic) { + *aIncomingFlags |= INCOMING_ARABICCHAR; + } else { + *aIncomingFlags &= ~INCOMING_ARABICCHAR; + } + if (inWhitespace) { + *aIncomingFlags |= INCOMING_WHITESPACE; + } else { + *aIncomingFlags &= ~INCOMING_WHITESPACE; + } + } + + if (outputStart + aLength != aOutput) { + flags |= TEXT_WAS_TRANSFORMED; + } + *aAnalysisFlags = flags; + return aOutput; +} + +uint8_t* +nsTextFrameUtils::TransformText(const uint8_t* aText, uint32_t aLength, + uint8_t* aOutput, + CompressionMode aCompression, + uint8_t* aIncomingFlags, + gfxSkipChars* aSkipChars, + uint32_t* aAnalysisFlags) +{ + uint32_t flags = 0; + uint8_t* outputStart = aOutput; + + if (aCompression == COMPRESS_NONE || + aCompression == COMPRESS_NONE_TRANSFORM_TO_SPACE) { + // Skip discardables. + uint32_t i; + for (i = 0; i < aLength; ++i) { + uint8_t ch = aText[i]; + if (IsDiscardable(ch, &flags)) { + aSkipChars->SkipChar(); + } else { + aSkipChars->KeepChar(); + if (aCompression == COMPRESS_NONE_TRANSFORM_TO_SPACE) { + if (ch == '\t' || ch == '\n') { + ch = ' '; + flags |= TEXT_WAS_TRANSFORMED; + } + } else { + // aCompression == COMPRESS_NONE + if (ch == '\t') { + flags |= TEXT_HAS_TAB; + } + } + *aOutput++ = ch; + } + } + *aIncomingFlags &= ~(INCOMING_ARABICCHAR | INCOMING_WHITESPACE); + } else { + bool inWhitespace = (*aIncomingFlags & INCOMING_WHITESPACE) != 0; + uint32_t i; + for (i = 0; i < aLength; ++i) { + uint8_t ch = aText[i]; + bool nowInWhitespace = ch == ' ' || ch == '\t' || + (ch == '\n' && aCompression == COMPRESS_WHITESPACE_NEWLINE); + if (!nowInWhitespace) { + if (IsDiscardable(ch, &flags)) { + aSkipChars->SkipChar(); + nowInWhitespace = inWhitespace; + } else { + *aOutput++ = ch; + aSkipChars->KeepChar(); + } + } else { + if (inWhitespace) { + aSkipChars->SkipChar(); + } else { + if (ch != ' ') { + flags |= TEXT_WAS_TRANSFORMED; + } + *aOutput++ = ' '; + aSkipChars->KeepChar(); + } + } + inWhitespace = nowInWhitespace; + } + *aIncomingFlags &= ~INCOMING_ARABICCHAR; + if (inWhitespace) { + *aIncomingFlags |= INCOMING_WHITESPACE; + } else { + *aIncomingFlags &= ~INCOMING_WHITESPACE; + } + } + + if (outputStart + aLength != aOutput) { + flags |= TEXT_WAS_TRANSFORMED; + } + *aAnalysisFlags = flags; + return aOutput; +} + +uint32_t +nsTextFrameUtils::ComputeApproximateLengthWithWhitespaceCompression( + nsIContent *aContent, const nsStyleText *aStyleText) +{ + const nsTextFragment *frag = aContent->GetText(); + // This is an approximation so we don't really need anything + // too fancy here. + uint32_t len; + if (aStyleText->WhiteSpaceIsSignificant()) { + len = frag->GetLength(); + } else { + bool is2b = frag->Is2b(); + union { + const char *s1b; + const char16_t *s2b; + } u; + if (is2b) { + u.s2b = frag->Get2b(); + } else { + u.s1b = frag->Get1b(); + } + bool prevWS = true; // more important to ignore blocks with + // only whitespace than get inline boundaries + // exactly right + len = 0; + for (uint32_t i = 0, i_end = frag->GetLength(); i < i_end; ++i) { + char16_t c = is2b ? u.s2b[i] : u.s1b[i]; + if (c == ' ' || c == '\n' || c == '\t' || c == '\r') { + if (!prevWS) { + ++len; + } + prevWS = true; + } else { + ++len; + prevWS = false; + } + } + } + return len; +} + +bool nsSkipCharsRunIterator::NextRun() { + do { + if (mRunLength) { + mIterator.AdvanceOriginal(mRunLength); + NS_ASSERTION(mRunLength > 0, "No characters in run (initial length too large?)"); + if (!mSkipped || mLengthIncludesSkipped) { + mRemainingLength -= mRunLength; + } + } + if (!mRemainingLength) + return false; + int32_t length; + mSkipped = mIterator.IsOriginalCharSkipped(&length); + mRunLength = std::min(length, mRemainingLength); + } while (!mVisitSkipped && mSkipped); + + return true; +} |