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/* -*- 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
/*
* A class which represents a fragment of text (eg inside a text
* node); if only codepoints below 256 are used, the text is stored as
* a char*; otherwise the text is stored as a char16_t*
*/
#include "nsTextFragment.h"
#include "nsCRT.h"
#include "nsReadableUtils.h"
#include "nsBidiUtils.h"
#include "nsUnicharUtils.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/SSE.h"
#include "mozilla/ppc.h"
#include "nsTextFragmentImpl.h"
#include <algorithm>
#define TEXTFRAG_WHITE_AFTER_NEWLINE 50
#define TEXTFRAG_MAX_NEWLINES 7
// Static buffer used for common fragments
static char* sSpaceSharedString[TEXTFRAG_MAX_NEWLINES + 1];
static char* sTabSharedString[TEXTFRAG_MAX_NEWLINES + 1];
static char sSingleCharSharedString[256];
using namespace mozilla;
// static
nsresult nsTextFragment::Init() {
// Create whitespace strings
uint32_t i;
for (i = 0; i <= TEXTFRAG_MAX_NEWLINES; ++i) {
sSpaceSharedString[i] = new char[1 + i + TEXTFRAG_WHITE_AFTER_NEWLINE];
sTabSharedString[i] = new char[1 + i + TEXTFRAG_WHITE_AFTER_NEWLINE];
sSpaceSharedString[i][0] = ' ';
sTabSharedString[i][0] = ' ';
uint32_t j;
for (j = 1; j < 1 + i; ++j) {
sSpaceSharedString[i][j] = '\n';
sTabSharedString[i][j] = '\n';
}
for (; j < (1 + i + TEXTFRAG_WHITE_AFTER_NEWLINE); ++j) {
sSpaceSharedString[i][j] = ' ';
sTabSharedString[i][j] = '\t';
}
}
// Create single-char strings
for (i = 0; i < 256; ++i) {
sSingleCharSharedString[i] = i;
}
return NS_OK;
}
// static
void nsTextFragment::Shutdown() {
uint32_t i;
for (i = 0; i <= TEXTFRAG_MAX_NEWLINES; ++i) {
delete[] sSpaceSharedString[i];
delete[] sTabSharedString[i];
sSpaceSharedString[i] = nullptr;
sTabSharedString[i] = nullptr;
}
}
nsTextFragment::~nsTextFragment() {
ReleaseText();
MOZ_COUNT_DTOR(nsTextFragment);
}
void nsTextFragment::ReleaseText() {
if (mState.mIs2b) {
NS_RELEASE(m2b);
} else if (mState.mLength && m1b && mState.mInHeap) {
free(const_cast<char*>(m1b));
}
m1b = nullptr;
mState.mIsBidi = false;
// Set mState.mIs2b, mState.mInHeap, and mState.mLength = 0 with mAllBits;
mAllBits = 0;
}
nsTextFragment& nsTextFragment::operator=(const nsTextFragment& aOther) {
ReleaseText();
if (aOther.mState.mLength) {
if (!aOther.mState.mInHeap) {
MOZ_ASSERT(!aOther.mState.mIs2b);
m1b = aOther.m1b;
} else if (aOther.mState.mIs2b) {
m2b = aOther.m2b;
NS_ADDREF(m2b);
} else {
m1b = static_cast<char*>(malloc(aOther.mState.mLength));
if (m1b) {
memcpy(const_cast<char*>(m1b), aOther.m1b, aOther.mState.mLength);
} else {
// allocate a buffer for a single REPLACEMENT CHARACTER
m2b = nsStringBuffer::Alloc(sizeof(char16_t) * 2).take();
if (!m2b) {
MOZ_CRASH("OOM!");
}
char16_t* data = static_cast<char16_t*>(m2b->Data());
data[0] = 0xFFFD; // REPLACEMENT CHARACTER
data[1] = char16_t(0);
mState.mIs2b = true;
mState.mInHeap = true;
mState.mLength = 1;
return *this;
}
}
mAllBits = aOther.mAllBits;
}
return *this;
}
static inline int32_t FirstNon8BitUnvectorized(const char16_t* str,
const char16_t* end) {
using p = Non8BitParameters<sizeof(size_t)>;
const size_t mask = p::mask();
const uint32_t alignMask = p::alignMask();
const uint32_t numUnicharsPerWord = p::numUnicharsPerWord();
const int32_t len = end - str;
int32_t i = 0;
// Align ourselves to a word boundary.
int32_t alignLen = std::min(
len, int32_t(((-NS_PTR_TO_INT32(str)) & alignMask) / sizeof(char16_t)));
for (; i < alignLen; i++) {
if (str[i] > 255) return i;
}
// Check one word at a time.
const int32_t wordWalkEnd =
((len - i) / numUnicharsPerWord) * numUnicharsPerWord;
for (; i < wordWalkEnd; i += numUnicharsPerWord) {
const size_t word = *reinterpret_cast<const size_t*>(str + i);
if (word & mask) return i;
}
// Take care of the remainder one character at a time.
for (; i < len; i++) {
if (str[i] > 255) return i;
}
return -1;
}
#if defined(MOZILLA_MAY_SUPPORT_SSE2)
# include "nsTextFragmentGenericFwd.h"
#endif
#ifdef __powerpc__
namespace mozilla {
namespace VMX {
int32_t FirstNon8Bit(const char16_t* str, const char16_t* end);
} // namespace VMX
} // namespace mozilla
#endif
/*
* This function returns -1 if all characters in str are 8 bit characters.
* Otherwise, it returns a value less than or equal to the index of the first
* non-8bit character in str. For example, if first non-8bit character is at
* position 25, it may return 25, or for example 24, or 16. But it guarantees
* there is no non-8bit character before returned value.
*/
static inline int32_t FirstNon8Bit(const char16_t* str, const char16_t* end) {
#ifdef MOZILLA_MAY_SUPPORT_SSE2
if (mozilla::supports_sse2()) {
return mozilla::FirstNon8Bit<xsimd::sse2>(str, end);
}
#elif defined(__powerpc__)
if (mozilla::supports_vmx()) {
return mozilla::VMX::FirstNon8Bit(str, end);
}
#endif
return FirstNon8BitUnvectorized(str, end);
}
bool nsTextFragment::SetTo(const char16_t* aBuffer, uint32_t aLength,
bool aUpdateBidi, bool aForce2b) {
if (MOZ_UNLIKELY(aLength > NS_MAX_TEXT_FRAGMENT_LENGTH)) {
return false;
}
if (aForce2b && mState.mIs2b && !m2b->IsReadonly()) {
uint32_t storageSize = m2b->StorageSize();
uint32_t neededSize = aLength * sizeof(char16_t);
if (!neededSize) {
if (storageSize < AutoStringDefaultStorageSize) {
// If we're storing small enough nsStringBuffer, let's preserve it.
static_cast<char16_t*>(m2b->Data())[0] = char16_t(0);
mState.mLength = 0;
mState.mIsBidi = false;
return true;
}
} else if ((neededSize < storageSize) &&
((storageSize / 2) <
(neededSize + AutoStringDefaultStorageSize))) {
// Don't try to reuse the existing nsStringBuffer, if it would have
// lots of unused space.
memcpy(m2b->Data(), aBuffer, neededSize);
static_cast<char16_t*>(m2b->Data())[aLength] = char16_t(0);
mState.mLength = aLength;
mState.mIsBidi = false;
if (aUpdateBidi) {
UpdateBidiFlag(aBuffer, aLength);
}
return true;
}
}
ReleaseText();
if (aLength == 0) {
return true;
}
char16_t firstChar = *aBuffer;
if (!aForce2b && aLength == 1 && firstChar < 256) {
m1b = sSingleCharSharedString + firstChar;
mState.mInHeap = false;
mState.mIs2b = false;
mState.mLength = 1;
return true;
}
const char16_t* ucp = aBuffer;
const char16_t* uend = aBuffer + aLength;
// Check if we can use a shared string
if (!aForce2b &&
aLength <= 1 + TEXTFRAG_WHITE_AFTER_NEWLINE + TEXTFRAG_MAX_NEWLINES &&
(firstChar == ' ' || firstChar == '\n' || firstChar == '\t')) {
if (firstChar == ' ') {
++ucp;
}
const char16_t* start = ucp;
while (ucp < uend && *ucp == '\n') {
++ucp;
}
const char16_t* endNewLine = ucp;
char16_t space = ucp < uend && *ucp == '\t' ? '\t' : ' ';
while (ucp < uend && *ucp == space) {
++ucp;
}
if (ucp == uend && endNewLine - start <= TEXTFRAG_MAX_NEWLINES &&
ucp - endNewLine <= TEXTFRAG_WHITE_AFTER_NEWLINE) {
char** strings = space == ' ' ? sSpaceSharedString : sTabSharedString;
m1b = strings[endNewLine - start];
// If we didn't find a space in the beginning, skip it now.
if (firstChar != ' ') {
++m1b;
}
mState.mInHeap = false;
mState.mIs2b = false;
mState.mLength = aLength;
return true;
}
}
// See if we need to store the data in ucs2 or not
int32_t first16bit = aForce2b ? 0 : FirstNon8Bit(ucp, uend);
if (first16bit != -1) { // aBuffer contains no non-8bit character
// Use ucs2 storage because we have to
CheckedUint32 m2bSize = CheckedUint32(aLength) + 1;
if (!m2bSize.isValid()) {
return false;
}
m2bSize *= sizeof(char16_t);
if (!m2bSize.isValid()) {
return false;
}
m2b = nsStringBuffer::Alloc(m2bSize.value()).take();
if (!m2b) {
return false;
}
memcpy(m2b->Data(), aBuffer, aLength * sizeof(char16_t));
static_cast<char16_t*>(m2b->Data())[aLength] = char16_t(0);
mState.mIs2b = true;
if (aUpdateBidi) {
UpdateBidiFlag(aBuffer + first16bit, aLength - first16bit);
}
} else {
// Use 1 byte storage because we can
char* buff = static_cast<char*>(malloc(aLength));
if (!buff) {
return false;
}
// Copy data
LossyConvertUtf16toLatin1(Span(aBuffer, aLength), Span(buff, aLength));
m1b = buff;
mState.mIs2b = false;
}
// Setup our fields
mState.mInHeap = true;
mState.mLength = aLength;
return true;
}
void nsTextFragment::CopyTo(char16_t* aDest, uint32_t aOffset,
uint32_t aCount) {
const CheckedUint32 endOffset = CheckedUint32(aOffset) + aCount;
if (!endOffset.isValid() || endOffset.value() > GetLength()) {
aCount = mState.mLength - aOffset;
}
if (aCount) {
if (mState.mIs2b) {
memcpy(aDest, Get2b() + aOffset, sizeof(char16_t) * aCount);
} else {
const char* cp = m1b + aOffset;
ConvertLatin1toUtf16(Span(cp, aCount), Span(aDest, aCount));
}
}
}
bool nsTextFragment::Append(const char16_t* aBuffer, uint32_t aLength,
bool aUpdateBidi, bool aForce2b) {
if (!aLength) {
return true;
}
// This is a common case because some callsites create a textnode
// with a value by creating the node and then calling AppendData.
if (mState.mLength == 0) {
return SetTo(aBuffer, aLength, aUpdateBidi, aForce2b);
}
// Should we optimize for aData.Length() == 0?
// FYI: Don't use CheckedInt in this method since here is very hot path
// in some performance tests.
if (NS_MAX_TEXT_FRAGMENT_LENGTH - mState.mLength < aLength) {
return false; // Would be overflown if we'd keep handling.
}
if (mState.mIs2b) {
size_t size = mState.mLength + aLength + 1;
if (SIZE_MAX / sizeof(char16_t) < size) {
return false; // Would be overflown if we'd keep handling.
}
size *= sizeof(char16_t);
// Already a 2-byte string so the result will be too
nsStringBuffer* buff = nullptr;
nsStringBuffer* bufferToRelease = nullptr;
if (m2b->IsReadonly()) {
buff = nsStringBuffer::Alloc(size).take();
if (!buff) {
return false;
}
bufferToRelease = m2b;
memcpy(static_cast<char16_t*>(buff->Data()), m2b->Data(),
mState.mLength * sizeof(char16_t));
} else {
buff = nsStringBuffer::Realloc(m2b, size);
if (!buff) {
return false;
}
}
char16_t* data = static_cast<char16_t*>(buff->Data());
memcpy(data + mState.mLength, aBuffer, aLength * sizeof(char16_t));
mState.mLength += aLength;
m2b = buff;
data[mState.mLength] = char16_t(0);
NS_IF_RELEASE(bufferToRelease);
if (aUpdateBidi) {
UpdateBidiFlag(aBuffer, aLength);
}
return true;
}
// Current string is a 1-byte string, check if the new data fits in one byte
// too.
int32_t first16bit = aForce2b ? 0 : FirstNon8Bit(aBuffer, aBuffer + aLength);
if (first16bit != -1) { // aBuffer contains no non-8bit character
size_t size = mState.mLength + aLength + 1;
if (SIZE_MAX / sizeof(char16_t) < size) {
return false; // Would be overflown if we'd keep handling.
}
size *= sizeof(char16_t);
// The old data was 1-byte, but the new is not so we have to expand it
// all to 2-byte
nsStringBuffer* buff = nsStringBuffer::Alloc(size).take();
if (!buff) {
return false;
}
// Copy data into buff
char16_t* data = static_cast<char16_t*>(buff->Data());
ConvertLatin1toUtf16(Span(m1b, mState.mLength), Span(data, mState.mLength));
memcpy(data + mState.mLength, aBuffer, aLength * sizeof(char16_t));
mState.mLength += aLength;
mState.mIs2b = true;
if (mState.mInHeap) {
free(const_cast<char*>(m1b));
}
data[mState.mLength] = char16_t(0);
m2b = buff;
mState.mInHeap = true;
if (aUpdateBidi) {
UpdateBidiFlag(aBuffer + first16bit, aLength - first16bit);
}
return true;
}
// The new and the old data is all 1-byte
size_t size = mState.mLength + aLength;
MOZ_ASSERT(sizeof(char) == 1);
char* buff;
if (mState.mInHeap) {
buff = static_cast<char*>(realloc(const_cast<char*>(m1b), size));
if (!buff) {
return false;
}
} else {
buff = static_cast<char*>(malloc(size));
if (!buff) {
return false;
}
memcpy(buff, m1b, mState.mLength);
mState.mInHeap = true;
}
// Copy aBuffer into buff.
LossyConvertUtf16toLatin1(Span(aBuffer, aLength),
Span(buff + mState.mLength, aLength));
m1b = buff;
mState.mLength += aLength;
return true;
}
/* virtual */
size_t nsTextFragment::SizeOfExcludingThis(
mozilla::MallocSizeOf aMallocSizeOf) const {
if (Is2b()) {
return m2b->SizeOfIncludingThisIfUnshared(aMallocSizeOf);
}
if (mState.mInHeap) {
return aMallocSizeOf(m1b);
}
return 0;
}
// To save time we only do this when we really want to know, not during
// every allocation
void nsTextFragment::UpdateBidiFlag(const char16_t* aBuffer, uint32_t aLength) {
if (mState.mIs2b && !mState.mIsBidi) {
if (HasRTLChars(Span(aBuffer, aLength))) {
mState.mIsBidi = true;
}
}
}
bool nsTextFragment::TextEquals(const nsTextFragment& aOther) const {
if (!Is2b()) {
// We're 1-byte.
if (!aOther.Is2b()) {
nsDependentCSubstring ourStr(Get1b(), GetLength());
return ourStr.Equals(
nsDependentCSubstring(aOther.Get1b(), aOther.GetLength()));
}
// We're 1-byte, the other thing is 2-byte. Instead of implementing a
// separate codepath for this, just use our code below.
return aOther.TextEquals(*this);
}
nsDependentSubstring ourStr(Get2b(), GetLength());
if (aOther.Is2b()) {
return ourStr.Equals(
nsDependentSubstring(aOther.Get2b(), aOther.GetLength()));
}
// We can't use EqualsASCII here, because the other string might not
// actually be ASCII. Just roll our own compare; do it in the simple way.
if (GetLength() != aOther.GetLength()) {
return false;
}
const char16_t* ourChars = Get2b();
const char* otherChars = aOther.Get1b();
for (uint32_t i = 0; i < GetLength(); ++i) {
if (ourChars[i] != static_cast<char16_t>(otherChars[i])) {
return false;
}
}
return true;
}