gecko-dev/layout/generic/nsTextFrameUtils.cpp

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/* -*- 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 "nsUnicharUtils.h"
#include "nsBidiUtils.h"
#include "nsIContent.h"
#include "nsStyleStruct.h"
#include "nsTextFragment.h"
#include <algorithm>
// XXX TODO implement transform of backslash to yen that nsTextTransform does
// when requested by PresContext->LanguageSpecificTransformType(). Do it with
// a new factory type that just munges the input stream. But first, check
// that we really still need this, it's only enabled via a hidden pref
// which defaults false...
#define UNICODE_ZWSP 0x200B
static bool IsDiscardable(PRUnichar 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;
}
if ((ch & 0xFF00) != 0x2000) {
// Not a Bidi control character
return false;
}
return IS_BIDI_CONTROL_CHAR(ch);
}
static bool IsDiscardable(uint8_t ch, uint32_t* aFlags)
{
if (ch == CH_SHY) {
*aFlags |= nsTextFrameUtils::TEXT_HAS_SHY;
return true;
}
return false;
}
PRUnichar*
nsTextFrameUtils::TransformText(const PRUnichar* aText, uint32_t aLength,
PRUnichar* aOutput,
CompressionMode aCompression,
uint8_t* aIncomingFlags,
gfxSkipCharsBuilder* aSkipChars,
uint32_t* aAnalysisFlags)
{
uint32_t flags = 0;
PRUnichar* outputStart = aOutput;
bool lastCharArabic = false;
if (aCompression == COMPRESS_NONE ||
aCompression == DISCARD_NEWLINE) {
// Skip discardables.
uint32_t i;
for (i = 0; i < aLength; ++i) {
PRUnichar ch = *aText++;
if (IsDiscardable(ch, &flags) ||
(ch == '\n' && aCompression == DISCARD_NEWLINE)) {
aSkipChars->SkipChar();
} else {
aSkipChars->KeepChar();
if (ch > ' ') {
lastCharArabic = IS_ARABIC_CHAR(ch);
} else 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) {
PRUnichar ch = *aText++;
bool nowInWhitespace;
if (ch == ' ' &&
(i + 1 >= aLength ||
!IsSpaceCombiningSequenceTail(aText, aLength - (i + 1)))) {
nowInWhitespace = true;
} else if (ch == '\n' && aCompression == COMPRESS_WHITESPACE_NEWLINE) {
if (i > 0 && IS_CJ_CHAR(aText[-1]) &&
i + 1 < aLength && IS_CJ_CHAR(aText[1])) {
// Discard newlines between CJK chars.
// XXX this really requires more context to get right!
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,
gfxSkipCharsBuilder* aSkipChars,
uint32_t* aAnalysisFlags)
{
uint32_t flags = 0;
uint8_t* outputStart = aOutput;
if (aCompression == COMPRESS_NONE ||
aCompression == DISCARD_NEWLINE) {
// Skip discardables.
uint32_t i;
for (i = 0; i < aLength; ++i) {
uint8_t ch = *aText++;
if (IsDiscardable(ch, &flags) ||
(ch == '\n' && aCompression == DISCARD_NEWLINE)) {
aSkipChars->SkipChar();
} else {
aSkipChars->KeepChar();
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++;
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 PRUnichar *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) {
PRUnichar 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;
}