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gecko-dev/xpcom/string/nsTSubstring.cpp
serge-sans-paille 18308210a8 Bug 1916234 - Remove global constructor from dom/html/nsGenericHTMLElement.cpp r=emilio 
Making static array constexpr and adjusting methods / codegen accordingly.

Differential Revision: https://phabricator.services.mozilla.com/D220813
2024-09-05 06:12:03 +00:00

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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
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "double-conversion/double-conversion.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/MathAlgorithms.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/Printf.h"
#include "mozilla/ResultExtensions.h"
#include "nsASCIIMask.h"
#include "nsCharTraits.h"
#include "nsISupports.h"
#include "nsString.h"
#include "nsTArray.h"
// It's not worthwhile to reallocate the buffer and memcpy the
// contents over when the size difference isn't large. With
// power-of-two allocation buckets and 64 as the typical inline
// capacity, considering that above 1000 there performance aspects
// of realloc and memcpy seem to be absorbed, relative to the old
// code, by the performance benefits of the new code being exact,
// we need to choose which transitions of 256 to 128, 512 to 256
// and 1024 to 512 to allow. As a guess, let's pick the middle
// one as the the largest potential transition that we forgo. So
// we'll shrink from 1024 bucket to 512 bucket but not from 512
// bucket to 256 bucket. We'll decide by comparing the difference
// of capacities. As bucket differences, the differences are 256
// and 512. Since the capacities have various overheads, we
// can't compare with 256 or 512 exactly but it's easier to
// compare to some number that's between the two, so it's
// far away from either to ignore the overheads.
const uint32_t kNsStringBufferShrinkingThreshold = 384;
using double_conversion::DoubleToStringConverter;
// ---------------------------------------------------------------------------
static const char16_t gNullChar = 0;
char* const nsCharTraits<char>::sEmptyBuffer =
(char*)const_cast<char16_t*>(&gNullChar);
char16_t* const nsCharTraits<char16_t>::sEmptyBuffer =
const_cast<char16_t*>(&gNullChar);
// ---------------------------------------------------------------------------
static void ReleaseData(void* aData, nsAString::DataFlags aFlags) {
if (aFlags & nsAString::DataFlags::REFCOUNTED) {
mozilla::StringBuffer::FromData(aData)->Release();
} else if (aFlags & nsAString::DataFlags::OWNED) {
// Treat this as destruction of a "StringAdopt" object for leak
// tracking purposes.
MOZ_LOG_DTOR(aData, "StringAdopt", 1);
free(aData);
}
// otherwise, nothing to do.
}
// ---------------------------------------------------------------------------
#ifdef XPCOM_STRING_CONSTRUCTOR_OUT_OF_LINE
template <typename T>
nsTSubstring<T>::nsTSubstring(char_type* aData, size_type aLength,
DataFlags aDataFlags, ClassFlags aClassFlags)
: ::mozilla::detail::nsTStringRepr<T>(aData, aLength, aDataFlags,
aClassFlags) {
AssertValid();
if (aDataFlags & DataFlags::OWNED) {
MOZ_LOG_CTOR(this->mData, "StringAdopt", 1);
}
}
#endif /* XPCOM_STRING_CONSTRUCTOR_OUT_OF_LINE */
/**
* helper function for down-casting a nsTSubstring to an nsTAutoString.
*/
template <typename T>
inline const nsTAutoString<T>* AsAutoString(const nsTSubstring<T>* aStr) {
return static_cast<const nsTAutoString<T>*>(aStr);
}
template <typename T>
mozilla::Result<mozilla::BulkWriteHandle<T>, nsresult>
nsTSubstring<T>::BulkWrite(size_type aCapacity, size_type aPrefixToPreserve,
bool aAllowShrinking) {
auto r = StartBulkWriteImpl(aCapacity, aPrefixToPreserve, aAllowShrinking);
if (MOZ_UNLIKELY(r.isErr())) {
return r.propagateErr();
}
return mozilla::BulkWriteHandle<T>(this, r.unwrap());
}
template <typename T>
auto nsTSubstring<T>::StartBulkWriteImpl(
size_type aCapacity, size_type aPrefixToPreserve, bool aAllowShrinking,
size_type aSuffixLength, size_type aOldSuffixStart,
size_type aNewSuffixStart) -> mozilla::Result<size_type, nsresult> {
// Note! Capacity does not include room for the terminating null char.
MOZ_ASSERT(aPrefixToPreserve <= aCapacity,
"Requested preservation of an overlong prefix.");
MOZ_ASSERT(aNewSuffixStart + aSuffixLength <= aCapacity,
"Requesed move of suffix to out-of-bounds location.");
// Can't assert aOldSuffixStart, because mLength may not be valid anymore,
// since this method allows itself to be called more than once.
// If zero capacity is requested, set the string to the special empty
// string.
if (MOZ_UNLIKELY(!aCapacity)) {
ReleaseData(this->mData, this->mDataFlags);
SetToEmptyBuffer();
return 0;
}
// Note! Capacity() returns 0 when the string is immutable.
const size_type curCapacity = Capacity();
bool shrinking = false;
// We've established that aCapacity > 0.
// |curCapacity == 0| means that the buffer is immutable or 0-sized, so we
// need to allocate a new buffer. We cannot use the existing buffer even
// though it might be large enough.
if (aCapacity <= curCapacity) {
if (aAllowShrinking) {
shrinking = true;
} else {
char_traits::move(this->mData + aNewSuffixStart,
this->mData + aOldSuffixStart, aSuffixLength);
if (aSuffixLength) {
char_traits::uninitialize(this->mData + aPrefixToPreserve,
XPCOM_MIN(aNewSuffixStart - aPrefixToPreserve,
kNsStringBufferMaxPoison));
char_traits::uninitialize(
this->mData + aNewSuffixStart + aSuffixLength,
XPCOM_MIN(curCapacity + 1 - aNewSuffixStart - aSuffixLength,
kNsStringBufferMaxPoison));
} else {
char_traits::uninitialize(this->mData + aPrefixToPreserve,
XPCOM_MIN(curCapacity + 1 - aPrefixToPreserve,
kNsStringBufferMaxPoison));
}
return curCapacity;
}
}
char_type* oldData = this->mData;
DataFlags oldFlags = this->mDataFlags;
char_type* newData;
DataFlags newDataFlags;
size_type newCapacity;
// If this is an nsTAutoStringN, it's possible that we can use the inline
// buffer.
if ((this->mClassFlags & ClassFlags::INLINE) &&
(aCapacity <= AsAutoString(this)->mInlineCapacity)) {
newCapacity = AsAutoString(this)->mInlineCapacity;
newData = (char_type*)AsAutoString(this)->mStorage;
newDataFlags = DataFlags::TERMINATED | DataFlags::INLINE;
} else {
// If |aCapacity > kMaxCapacity|, then our doubling algorithm may not be
// able to allocate it. Just bail out in cases like that. We don't want
// to be allocating 2GB+ strings anyway.
static_assert((sizeof(mozilla::StringBuffer) & 0x1) == 0,
"bad size for mozilla::StringBuffer");
if (MOZ_UNLIKELY(!this->CheckCapacity(aCapacity))) {
return mozilla::Err(NS_ERROR_OUT_OF_MEMORY);
}
// We increase our capacity so that the allocated buffer grows
// exponentially, which gives us amortized O(1) appending. Below the
// threshold, we use powers-of-two. Above the threshold, we grow by at
// least 1.125, rounding up to the nearest MiB.
const size_type slowGrowthThreshold = 8 * 1024 * 1024;
// mozilla::StringBuffer allocates sizeof(mozilla::StringBuffer) + passed
// size, and storageSize below wants extra 1 * sizeof(char_type).
const size_type neededExtraSpace =
sizeof(mozilla::StringBuffer) / sizeof(char_type) + 1;
size_type temp;
if (aCapacity >= slowGrowthThreshold) {
size_type minNewCapacity =
curCapacity + (curCapacity >> 3); // multiply by 1.125
temp = XPCOM_MAX(aCapacity, minNewCapacity) + neededExtraSpace;
// Round up to the next multiple of MiB, but ensure the expected
// capacity doesn't include the extra space required by
// mozilla::StringBuffer and null-termination.
const size_t MiB = 1 << 20;
temp = (MiB * ((temp + MiB - 1) / MiB)) - neededExtraSpace;
} else {
// Round up to the next power of two.
temp =
mozilla::RoundUpPow2(aCapacity + neededExtraSpace) - neededExtraSpace;
}
newCapacity = XPCOM_MIN(temp, base_string_type::kMaxCapacity);
MOZ_ASSERT(newCapacity >= aCapacity,
"should have hit the early return at the top");
// Avoid shrinking if the new buffer size is close to the old. Note that
// unsigned underflow is defined behavior.
if ((curCapacity - newCapacity) <= kNsStringBufferShrinkingThreshold &&
(this->mDataFlags & DataFlags::REFCOUNTED)) {
MOZ_ASSERT(aAllowShrinking, "How come we didn't return earlier?");
// We're already close enough to the right size.
newData = oldData;
newCapacity = curCapacity;
} else {
size_type storageSize = (newCapacity + 1) * sizeof(char_type);
// Since we allocate only by powers of 2 we always fit into a full
// mozjemalloc bucket, it's not useful to use realloc, which may spend
// time uselessly copying too much.
mozilla::StringBuffer* newHdr =
mozilla::StringBuffer::Alloc(storageSize).take();
if (newHdr) {
newData = (char_type*)newHdr->Data();
} else if (shrinking) {
// We're still in a consistent state.
//
// Since shrinking is just a memory footprint optimization, we
// don't propagate OOM if we tried to shrink in order to avoid
// OOM crashes from infallible callers. If we're lucky, soon enough
// a fallible caller reaches OOM and is able to deal or we end up
// disposing of this string before reaching OOM again.
newData = oldData;
newCapacity = curCapacity;
} else {
return mozilla::Err(NS_ERROR_OUT_OF_MEMORY);
}
}
newDataFlags = DataFlags::TERMINATED | DataFlags::REFCOUNTED;
}
this->mData = newData;
this->mDataFlags = newDataFlags;
if (oldData == newData) {
char_traits::move(newData + aNewSuffixStart, oldData + aOldSuffixStart,
aSuffixLength);
if (aSuffixLength) {
char_traits::uninitialize(this->mData + aPrefixToPreserve,
XPCOM_MIN(aNewSuffixStart - aPrefixToPreserve,
kNsStringBufferMaxPoison));
char_traits::uninitialize(
this->mData + aNewSuffixStart + aSuffixLength,
XPCOM_MIN(newCapacity + 1 - aNewSuffixStart - aSuffixLength,
kNsStringBufferMaxPoison));
} else {
char_traits::uninitialize(this->mData + aPrefixToPreserve,
XPCOM_MIN(newCapacity + 1 - aPrefixToPreserve,
kNsStringBufferMaxPoison));
}
} else {
char_traits::copy(newData, oldData, aPrefixToPreserve);
char_traits::copy(newData + aNewSuffixStart, oldData + aOldSuffixStart,
aSuffixLength);
ReleaseData(oldData, oldFlags);
}
return newCapacity;
}
template <typename T>
void nsTSubstring<T>::FinishBulkWriteImpl(size_type aLength) {
if (aLength) {
FinishBulkWriteImplImpl(aLength);
} else {
ReleaseData(this->mData, this->mDataFlags);
SetToEmptyBuffer();
}
AssertValid();
}
template <typename T>
void nsTSubstring<T>::Finalize() {
ReleaseData(this->mData, this->mDataFlags);
// this->mData, this->mLength, and this->mDataFlags are purposefully left
// dangling
}
template <typename T>
bool nsTSubstring<T>::ReplacePrep(index_type aCutStart, size_type aCutLength,
size_type aNewLength) {
aCutLength = XPCOM_MIN(aCutLength, this->mLength - aCutStart);
mozilla::CheckedInt<size_type> newTotalLen = this->Length();
newTotalLen += aNewLength;
newTotalLen -= aCutLength;
if (!newTotalLen.isValid()) {
return false;
}
if (aCutStart == this->mLength && Capacity() > newTotalLen.value()) {
this->mDataFlags &= ~DataFlags::VOIDED;
this->mData[newTotalLen.value()] = char_type(0);
this->mLength = newTotalLen.value();
return true;
}
return ReplacePrepInternal(aCutStart, aCutLength, aNewLength,
newTotalLen.value());
}
template <typename T>
bool nsTSubstring<T>::ReplacePrepInternal(index_type aCutStart,
size_type aCutLen, size_type aFragLen,
size_type aNewLen) {
size_type newSuffixStart = aCutStart + aFragLen;
size_type oldSuffixStart = aCutStart + aCutLen;
size_type suffixLength = this->mLength - oldSuffixStart;
mozilla::Result<size_type, nsresult> r = StartBulkWriteImpl(
aNewLen, aCutStart, false, suffixLength, oldSuffixStart, newSuffixStart);
if (r.isErr()) {
return false;
}
FinishBulkWriteImpl(aNewLen);
return true;
}
template <typename T>
typename nsTSubstring<T>::size_type nsTSubstring<T>::Capacity() const {
// return 0 to indicate an immutable or 0-sized buffer
size_type capacity;
if (this->mDataFlags & DataFlags::REFCOUNTED) {
// if the string is readonly, then we pretend that it has no capacity.
mozilla::StringBuffer* hdr = mozilla::StringBuffer::FromData(this->mData);
if (hdr->IsReadonly()) {
capacity = 0;
} else {
capacity = (size_t(hdr->StorageSize()) / sizeof(char_type)) - 1;
}
} else if (this->mDataFlags & DataFlags::INLINE) {
MOZ_ASSERT(this->mClassFlags & ClassFlags::INLINE);
capacity = AsAutoString(this)->mInlineCapacity;
} else if (this->mDataFlags & DataFlags::OWNED) {
// we don't store the capacity of an adopted buffer because that would
// require an additional member field. the best we can do is base the
// capacity on our length. remains to be seen if this is the right
// trade-off.
capacity = this->mLength;
} else {
capacity = 0;
}
return capacity;
}
template <typename T>
bool nsTSubstring<T>::EnsureMutable(size_type aNewLen) {
if (aNewLen == size_type(-1) || aNewLen == this->mLength) {
if (this->mDataFlags & (DataFlags::INLINE | DataFlags::OWNED)) {
return true;
}
if ((this->mDataFlags & DataFlags::REFCOUNTED) &&
!mozilla::StringBuffer::FromData(this->mData)->IsReadonly()) {
return true;
}
aNewLen = this->mLength;
}
return SetLength(aNewLen, mozilla::fallible);
}
// ---------------------------------------------------------------------------
// This version of Assign is optimized for single-character assignment.
template <typename T>
void nsTSubstring<T>::Assign(char_type aChar) {
if (MOZ_UNLIKELY(!Assign(aChar, mozilla::fallible))) {
AllocFailed(1);
}
}
template <typename T>
bool nsTSubstring<T>::Assign(char_type aChar, const fallible_t&) {
auto r = StartBulkWriteImpl(1, 0, true);
if (MOZ_UNLIKELY(r.isErr())) {
return false;
}
*this->mData = aChar;
FinishBulkWriteImpl(1);
return true;
}
template <typename T>
void nsTSubstring<T>::Assign(const char_type* aData, size_type aLength) {
if (MOZ_UNLIKELY(!Assign(aData, aLength, mozilla::fallible))) {
AllocFailed(aLength == size_type(-1) ? char_traits::length(aData)
: aLength);
}
}
template <typename T>
bool nsTSubstring<T>::Assign(const char_type* aData,
const fallible_t& aFallible) {
return Assign(aData, size_type(-1), aFallible);
}
template <typename T>
bool nsTSubstring<T>::Assign(const char_type* aData, size_type aLength,
const fallible_t& aFallible) {
if (!aData || aLength == 0) {
Truncate();
return true;
}
if (MOZ_UNLIKELY(aLength == size_type(-1))) {
aLength = char_traits::length(aData);
}
if (MOZ_UNLIKELY(this->IsDependentOn(aData, aData + aLength))) {
return Assign(string_type(aData, aLength), aFallible);
}
auto r = StartBulkWriteImpl(aLength, 0, true);
if (MOZ_UNLIKELY(r.isErr())) {
return false;
}
char_traits::copy(this->mData, aData, aLength);
FinishBulkWriteImpl(aLength);
return true;
}
template <typename T>
void nsTSubstring<T>::AssignASCII(const char* aData, size_type aLength) {
if (MOZ_UNLIKELY(!AssignASCII(aData, aLength, mozilla::fallible))) {
AllocFailed(aLength);
}
}
template <typename T>
void nsTSubstring<T>::AssignASCII(const nsLiteralCString& aData) {
AssignASCII(aData.get(), aData.Length());
}
template <typename T>
bool nsTSubstring<T>::AssignASCII(const char* aData, size_type aLength,
const fallible_t& aFallible) {
MOZ_ASSERT(aLength != size_type(-1));
// A Unicode string can't depend on an ASCII string buffer,
// so this dependence check only applies to CStrings.
if constexpr (std::is_same_v<T, char>) {
if (this->IsDependentOn(aData, aData + aLength)) {
return Assign(string_type(aData, aLength), aFallible);
}
}
auto r = StartBulkWriteImpl(aLength, 0, true);
if (MOZ_UNLIKELY(r.isErr())) {
return false;
}
char_traits::copyASCII(this->mData, aData, aLength);
FinishBulkWriteImpl(aLength);
return true;
}
template <typename T>
void nsTSubstring<T>::AssignLiteral(const char_type* aData, size_type aLength) {
ReleaseData(this->mData, this->mDataFlags);
SetData(const_cast<char_type*>(aData), aLength,
DataFlags::TERMINATED | DataFlags::LITERAL);
}
template <typename T>
void nsTSubstring<T>::Assign(const self_type& aStr) {
if (!Assign(aStr, mozilla::fallible)) {
AllocFailed(aStr.Length());
}
}
template <typename T>
bool nsTSubstring<T>::Assign(const self_type& aStr,
const fallible_t& aFallible) {
// |aStr| could be sharable. We need to check its flags to know how to
// deal with it.
if (&aStr == this) {
return true;
}
if (!aStr.mLength) {
Truncate();
this->mDataFlags |= aStr.mDataFlags & DataFlags::VOIDED;
return true;
}
if (aStr.mDataFlags & DataFlags::REFCOUNTED) {
// nice! we can avoid a string copy :-)
// |aStr| should be null-terminated
NS_ASSERTION(aStr.mDataFlags & DataFlags::TERMINATED,
"shared, but not terminated");
ReleaseData(this->mData, this->mDataFlags);
SetData(aStr.mData, aStr.mLength,
DataFlags::TERMINATED | DataFlags::REFCOUNTED);
// get an owning reference to the this->mData
mozilla::StringBuffer::FromData(this->mData)->AddRef();
return true;
}
if (aStr.mDataFlags & DataFlags::LITERAL) {
MOZ_ASSERT(aStr.mDataFlags & DataFlags::TERMINATED, "Unterminated literal");
AssignLiteral(aStr.mData, aStr.mLength);
return true;
}
// else, treat this like an ordinary assignment.
return Assign(aStr.Data(), aStr.Length(), aFallible);
}
template <typename T>
void nsTSubstring<T>::Assign(self_type&& aStr) {
if (!Assign(std::move(aStr), mozilla::fallible)) {
AllocFailed(aStr.Length());
}
}
template <typename T>
void nsTSubstring<T>::AssignOwned(self_type&& aStr) {
MOZ_ASSERT(aStr.mDataFlags & (DataFlags::REFCOUNTED | DataFlags::OWNED),
"neither shared nor owned");
// If they have a REFCOUNTED or OWNED buffer, we can avoid a copy - so steal
// their buffer and reset them to the empty string.
// |aStr| should be null-terminated
MOZ_ASSERT(aStr.mDataFlags & DataFlags::TERMINATED,
"shared or owned, but not terminated");
ReleaseData(this->mData, this->mDataFlags);
SetData(aStr.mData, aStr.mLength, aStr.mDataFlags);
aStr.SetToEmptyBuffer();
}
template <typename T>
bool nsTSubstring<T>::Assign(self_type&& aStr, const fallible_t& aFallible) {
// We're moving |aStr| in this method, so we need to try to steal the data,
// and in the fallback perform a copy-assignment followed by a truncation of
// the original string.
if (&aStr == this) {
NS_WARNING("Move assigning a string to itself?");
return true;
}
if (aStr.mDataFlags & (DataFlags::REFCOUNTED | DataFlags::OWNED)) {
AssignOwned(std::move(aStr));
return true;
}
// Otherwise treat this as a normal assignment, and truncate the moved string.
// We don't truncate the source string if the allocation failed.
if (!Assign(aStr, aFallible)) {
return false;
}
aStr.Truncate();
return true;
}
template <typename T>
void nsTSubstring<T>::Assign(const substring_tuple_type& aTuple) {
if (!Assign(aTuple, mozilla::fallible)) {
AllocFailed(aTuple.Length());
}
}
template <typename T>
bool nsTSubstring<T>::AssignNonDependent(const substring_tuple_type& aTuple,
size_type aTupleLength,
const mozilla::fallible_t& aFallible) {
NS_ASSERTION(aTuple.Length() == aTupleLength, "wrong length passed");
auto r = StartBulkWriteImpl(aTupleLength);
if (r.isErr()) {
return false;
}
aTuple.WriteTo(this->mData, aTupleLength);
FinishBulkWriteImpl(aTupleLength);
return true;
}
template <typename T>
bool nsTSubstring<T>::Assign(const substring_tuple_type& aTuple,
const fallible_t& aFallible) {
const auto [isDependentOnThis, tupleLength] =
aTuple.IsDependentOnWithLength(this->mData, this->mData + this->mLength);
if (isDependentOnThis) {
string_type temp;
self_type& tempSubstring = temp;
if (!tempSubstring.AssignNonDependent(aTuple, tupleLength, aFallible)) {
return false;
}
AssignOwned(std::move(temp));
return true;
}
return AssignNonDependent(aTuple, tupleLength, aFallible);
}
template <typename T>
void nsTSubstring<T>::Adopt(char_type* aData, size_type aLength) {
if (aData) {
ReleaseData(this->mData, this->mDataFlags);
if (aLength == size_type(-1)) {
aLength = char_traits::length(aData);
}
SetData(aData, aLength, DataFlags::TERMINATED | DataFlags::OWNED);
// Treat this as construction of a "StringAdopt" object for leak
// tracking purposes.
MOZ_LOG_CTOR(this->mData, "StringAdopt", 1);
} else {
SetIsVoid(true);
}
}
// This version of Replace is optimized for single-character replacement.
template <typename T>
void nsTSubstring<T>::Replace(index_type aCutStart, size_type aCutLength,
char_type aChar) {
aCutStart = XPCOM_MIN(aCutStart, this->Length());
if (ReplacePrep(aCutStart, aCutLength, 1)) {
this->mData[aCutStart] = aChar;
}
}
template <typename T>
bool nsTSubstring<T>::Replace(index_type aCutStart, size_type aCutLength,
char_type aChar, const fallible_t&) {
aCutStart = XPCOM_MIN(aCutStart, this->Length());
if (!ReplacePrep(aCutStart, aCutLength, 1)) {
return false;
}
this->mData[aCutStart] = aChar;
return true;
}
template <typename T>
void nsTSubstring<T>::Replace(index_type aCutStart, size_type aCutLength,
const char_type* aData, size_type aLength) {
if (!Replace(aCutStart, aCutLength, aData, aLength, mozilla::fallible)) {
AllocFailed(this->Length() - aCutLength + 1);
}
}
template <typename T>
bool nsTSubstring<T>::Replace(index_type aCutStart, size_type aCutLength,
const char_type* aData, size_type aLength,
const fallible_t& aFallible) {
// unfortunately, some callers pass null :-(
if (!aData) {
aLength = 0;
} else {
if (aLength == size_type(-1)) {
aLength = char_traits::length(aData);
}
if (this->IsDependentOn(aData, aData + aLength)) {
nsTAutoString<T> temp(aData, aLength);
return Replace(aCutStart, aCutLength, temp, aFallible);
}
}
aCutStart = XPCOM_MIN(aCutStart, this->Length());
bool ok = ReplacePrep(aCutStart, aCutLength, aLength);
if (!ok) {
return false;
}
if (aLength > 0) {
char_traits::copy(this->mData + aCutStart, aData, aLength);
}
return true;
}
template <typename T>
void nsTSubstring<T>::Replace(index_type aCutStart, size_type aCutLength,
const substring_tuple_type& aTuple) {
const auto [isDependentOnThis, tupleLength] =
aTuple.IsDependentOnWithLength(this->mData, this->mData + this->mLength);
if (isDependentOnThis) {
nsTAutoString<T> temp;
if (!temp.AssignNonDependent(aTuple, tupleLength, mozilla::fallible)) {
AllocFailed(tupleLength);
}
Replace(aCutStart, aCutLength, temp);
return;
}
aCutStart = XPCOM_MIN(aCutStart, this->Length());
if (ReplacePrep(aCutStart, aCutLength, tupleLength) && tupleLength > 0) {
aTuple.WriteTo(this->mData + aCutStart, tupleLength);
}
}
template <typename T>
void nsTSubstring<T>::ReplaceLiteral(index_type aCutStart, size_type aCutLength,
const char_type* aData,
size_type aLength) {
aCutStart = XPCOM_MIN(aCutStart, this->Length());
if (!aCutStart && aCutLength == this->Length() &&
!(this->mDataFlags & DataFlags::REFCOUNTED)) {
// Check for REFCOUNTED above to avoid undoing the effect of
// SetCapacity().
AssignLiteral(aData, aLength);
} else if (ReplacePrep(aCutStart, aCutLength, aLength) && aLength > 0) {
char_traits::copy(this->mData + aCutStart, aData, aLength);
}
}
template <typename T>
void nsTSubstring<T>::Append(char_type aChar) {
if (MOZ_UNLIKELY(!Append(aChar, mozilla::fallible))) {
AllocFailed(this->mLength + 1);
}
}
template <typename T>
bool nsTSubstring<T>::Append(char_type aChar, const fallible_t& aFallible) {
size_type oldLen = this->mLength;
size_type newLen = oldLen + 1; // Can't overflow
auto r = StartBulkWriteImpl(newLen, oldLen, false);
if (MOZ_UNLIKELY(r.isErr())) {
return false;
}
this->mData[oldLen] = aChar;
FinishBulkWriteImpl(newLen);
return true;
}
template <typename T>
void nsTSubstring<T>::Append(const char_type* aData, size_type aLength) {
if (MOZ_UNLIKELY(!Append(aData, aLength, mozilla::fallible))) {
AllocFailed(this->mLength + (aLength == size_type(-1)
? char_traits::length(aData)
: aLength));
}
}
template <typename T>
bool nsTSubstring<T>::Append(const char_type* aData, size_type aLength,
const fallible_t& aFallible) {
if (MOZ_UNLIKELY(aLength == size_type(-1))) {
aLength = char_traits::length(aData);
}
if (MOZ_UNLIKELY(!aLength)) {
// Avoid undoing the effect of SetCapacity() if both
// mLength and aLength are zero.
return true;
}
if (MOZ_UNLIKELY(this->IsDependentOn(aData, aData + aLength))) {
return Append(string_type(aData, aLength), mozilla::fallible);
}
size_type oldLen = this->mLength;
mozilla::CheckedInt<size_type> newLen(oldLen);
newLen += aLength;
if (MOZ_UNLIKELY(!newLen.isValid())) {
return false;
}
auto r = StartBulkWriteImpl(newLen.value(), oldLen, false);
if (MOZ_UNLIKELY(r.isErr())) {
return false;
}
char_traits::copy(this->mData + oldLen, aData, aLength);
FinishBulkWriteImpl(newLen.value());
return true;
}
template <typename T>
void nsTSubstring<T>::AppendASCII(const char* aData, size_type aLength) {
if (MOZ_UNLIKELY(!AppendASCII(aData, aLength, mozilla::fallible))) {
AllocFailed(this->mLength +
(aLength == size_type(-1) ? strlen(aData) : aLength));
}
}
template <typename T>
void nsTSubstring<T>::AppendASCII(const nsLiteralCString& aData) {
AppendASCII(aData.get(), aData.Length());
}
template <typename T>
bool nsTSubstring<T>::AppendASCII(const char* aData,
const fallible_t& aFallible) {
return AppendASCII(aData, size_type(-1), aFallible);
}
template <typename T>
bool nsTSubstring<T>::AppendASCII(const char* aData, size_type aLength,
const fallible_t& aFallible) {
if (MOZ_UNLIKELY(aLength == size_type(-1))) {
aLength = strlen(aData);
}
if (MOZ_UNLIKELY(!aLength)) {
// Avoid undoing the effect of SetCapacity() if both
// mLength and aLength are zero.
return true;
}
if constexpr (std::is_same_v<T, char>) {
// 16-bit string can't depend on an 8-bit buffer
if (MOZ_UNLIKELY(this->IsDependentOn(aData, aData + aLength))) {
return Append(string_type(aData, aLength), mozilla::fallible);
}
}
size_type oldLen = this->mLength;
mozilla::CheckedInt<size_type> newLen(oldLen);
newLen += aLength;
if (MOZ_UNLIKELY(!newLen.isValid())) {
return false;
}
auto r = StartBulkWriteImpl(newLen.value(), oldLen, false);
if (MOZ_UNLIKELY(r.isErr())) {
return false;
}
char_traits::copyASCII(this->mData + oldLen, aData, aLength);
FinishBulkWriteImpl(newLen.value());
return true;
}
template <typename T>
void nsTSubstring<T>::Append(const self_type& aStr) {
if (MOZ_UNLIKELY(!Append(aStr, mozilla::fallible))) {
AllocFailed(this->mLength + aStr.Length());
}
}
template <typename T>
bool nsTSubstring<T>::Append(const self_type& aStr,
const fallible_t& aFallible) {
// Check refcounted to avoid undoing the effects of SetCapacity().
if (MOZ_UNLIKELY(!this->mLength &&
!(this->mDataFlags & DataFlags::REFCOUNTED))) {
return Assign(aStr, mozilla::fallible);
}
return Append(aStr.BeginReading(), aStr.Length(), mozilla::fallible);
}
template <typename T>
void nsTSubstring<T>::Append(const substring_tuple_type& aTuple) {
if (MOZ_UNLIKELY(!Append(aTuple, mozilla::fallible))) {
AllocFailed(this->mLength + aTuple.Length());
}
}
template <typename T>
bool nsTSubstring<T>::Append(const substring_tuple_type& aTuple,
const fallible_t& aFallible) {
const auto [isDependentOnThis, tupleLength] =
aTuple.IsDependentOnWithLength(this->mData, this->mData + this->mLength);
if (MOZ_UNLIKELY(!tupleLength)) {
// Avoid undoing the effect of SetCapacity() if both
// mLength and tupleLength are zero.
return true;
}
if (MOZ_UNLIKELY(isDependentOnThis)) {
return Append(string_type(aTuple), aFallible);
}
size_type oldLen = this->mLength;
mozilla::CheckedInt<size_type> newLen(oldLen);
newLen += tupleLength;
if (MOZ_UNLIKELY(!newLen.isValid())) {
return false;
}
auto r = StartBulkWriteImpl(newLen.value(), oldLen, false);
if (MOZ_UNLIKELY(r.isErr())) {
return false;
}
aTuple.WriteTo(this->mData + oldLen, tupleLength);
FinishBulkWriteImpl(newLen.value());
return true;
}
template <typename T>
void nsTSubstring<T>::SetCapacity(size_type aCapacity) {
if (!SetCapacity(aCapacity, mozilla::fallible)) {
AllocFailed(aCapacity);
}
}
template <typename T>
bool nsTSubstring<T>::SetCapacity(size_type aCapacity, const fallible_t&) {
size_type length = this->mLength;
// This method can no longer be used to shorten the
// logical length.
size_type capacity = XPCOM_MAX(aCapacity, length);
auto r = StartBulkWriteImpl(capacity, length, true);
if (r.isErr()) {
return false;
}
if (MOZ_UNLIKELY(!capacity)) {
// Zero capacity was requested on a zero-length
// string. In this special case, we are pointing
// to the special empty buffer, which is already
// zero-terminated and not writable, so we must
// not attempt to zero-terminate it.
AssertValid();
return true;
}
// FinishBulkWriteImpl with argument zero releases
// the heap-allocated buffer. However, SetCapacity()
// is a special case that allows mLength to be zero
// while a heap-allocated buffer exists.
// By calling FinishBulkWriteImplImpl, we skip the
// zero case handling that's inappropriate in the
// SetCapacity() case.
FinishBulkWriteImplImpl(length);
return true;
}
template <typename T>
void nsTSubstring<T>::SetLength(size_type aLength) {
if (!SetLength(aLength, mozilla::fallible)) {
AllocFailed(aLength);
}
}
template <typename T>
bool nsTSubstring<T>::SetLength(size_type aLength,
const fallible_t& aFallible) {
size_type preserve = XPCOM_MIN(aLength, this->Length());
auto r = StartBulkWriteImpl(aLength, preserve, true);
if (r.isErr()) {
return false;
}
FinishBulkWriteImpl(aLength);
return true;
}
template <typename T>
void nsTSubstring<T>::Truncate() {
ReleaseData(this->mData, this->mDataFlags);
SetToEmptyBuffer();
AssertValid();
}
template <typename T>
void nsTSubstring<T>::SetIsVoid(bool aVal) {
if (aVal) {
Truncate();
this->mDataFlags |= DataFlags::VOIDED;
} else {
this->mDataFlags &= ~DataFlags::VOIDED;
}
}
template <typename T>
void nsTSubstring<T>::StripChar(char_type aChar) {
if (this->mLength == 0) {
return;
}
if (!EnsureMutable()) { // XXX do this lazily?
AllocFailed(this->mLength);
}
// XXX(darin): this code should defer writing until necessary.
char_type* to = this->mData;
char_type* from = this->mData;
char_type* end = this->mData + this->mLength;
while (from < end) {
char_type theChar = *from++;
if (aChar != theChar) {
*to++ = theChar;
}
}
*to = char_type(0); // add the null
this->mLength = to - this->mData;
}
template <typename T>
void nsTSubstring<T>::StripChars(const char_type* aChars) {
if (this->mLength == 0) {
return;
}
if (!EnsureMutable()) { // XXX do this lazily?
AllocFailed(this->mLength);
}
// XXX(darin): this code should defer writing until necessary.
char_type* to = this->mData;
char_type* from = this->mData;
char_type* end = this->mData + this->mLength;
while (from < end) {
char_type theChar = *from++;
const char_type* test = aChars;
for (; *test && *test != theChar; ++test);
if (!*test) {
// Not stripped, copy this char.
*to++ = theChar;
}
}
*to = char_type(0); // add the null
this->mLength = to - this->mData;
}
template <typename T>
void nsTSubstring<T>::StripTaggedASCII(const ASCIIMaskArray& aToStrip) {
if (this->mLength == 0) {
return;
}
size_t untaggedPrefixLength = 0;
for (; untaggedPrefixLength < this->mLength; ++untaggedPrefixLength) {
uint32_t theChar = (uint32_t)this->mData[untaggedPrefixLength];
if (mozilla::ASCIIMask::IsMasked(aToStrip, theChar)) {
break;
}
}
if (untaggedPrefixLength == this->mLength) {
return;
}
if (!EnsureMutable()) {
AllocFailed(this->mLength);
}
char_type* to = this->mData + untaggedPrefixLength;
char_type* from = to;
char_type* end = this->mData + this->mLength;
while (from < end) {
uint32_t theChar = (uint32_t)*from++;
// Replacing this with a call to ASCIIMask::IsMasked
// regresses performance somewhat, so leaving it inlined.
if (!mozilla::ASCIIMask::IsMasked(aToStrip, theChar)) {
// Not stripped, copy this char.
*to++ = (char_type)theChar;
}
}
*to = char_type(0); // add the null
this->mLength = to - this->mData;
}
template <typename T>
void nsTSubstring<T>::StripCRLF() {
// Expanding this call to copy the code from StripTaggedASCII
// instead of just calling it does somewhat help with performance
// but it is not worth it given the duplicated code.
StripTaggedASCII(mozilla::ASCIIMask::MaskCRLF());
}
template <typename T>
struct MOZ_STACK_CLASS PrintfAppend : public mozilla::PrintfTarget {
explicit PrintfAppend(nsTSubstring<T>* aString) : mString(aString) {}
bool append(const char* aStr, size_t aLen) override {
if (aLen == 0) {
return true;
}
mString->AppendASCII(aStr, aLen);
return true;
}
private:
nsTSubstring<T>* mString;
};
template <typename T>
void nsTSubstring<T>::AppendPrintf(const char* aFormat, ...) {
PrintfAppend<T> appender(this);
va_list ap;
va_start(ap, aFormat);
bool r = appender.vprint(aFormat, ap);
if (!r) {
MOZ_CRASH("Allocation or other failure in PrintfTarget::print");
}
va_end(ap);
}
template <typename T>
void nsTSubstring<T>::AppendVprintf(const char* aFormat, va_list aAp) {
PrintfAppend<T> appender(this);
bool r = appender.vprint(aFormat, aAp);
if (!r) {
MOZ_CRASH("Allocation or other failure in PrintfTarget::print");
}
}
template <typename T>
void nsTSubstring<T>::AppendIntDec(int32_t aInteger) {
PrintfAppend<T> appender(this);
bool r = appender.appendIntDec(aInteger);
if (MOZ_UNLIKELY(!r)) {
MOZ_CRASH("Allocation or other failure while appending integers");
}
}
template <typename T>
void nsTSubstring<T>::AppendIntDec(uint32_t aInteger) {
PrintfAppend<T> appender(this);
bool r = appender.appendIntDec(aInteger);
if (MOZ_UNLIKELY(!r)) {
MOZ_CRASH("Allocation or other failure while appending integers");
}
}
template <typename T>
void nsTSubstring<T>::AppendIntOct(uint32_t aInteger) {
PrintfAppend<T> appender(this);
bool r = appender.appendIntOct(aInteger);
if (MOZ_UNLIKELY(!r)) {
MOZ_CRASH("Allocation or other failure while appending integers");
}
}
template <typename T>
void nsTSubstring<T>::AppendIntHex(uint32_t aInteger) {
PrintfAppend<T> appender(this);
bool r = appender.appendIntHex(aInteger);
if (MOZ_UNLIKELY(!r)) {
MOZ_CRASH("Allocation or other failure while appending integers");
}
}
template <typename T>
void nsTSubstring<T>::AppendIntDec(int64_t aInteger) {
PrintfAppend<T> appender(this);
bool r = appender.appendIntDec(aInteger);
if (MOZ_UNLIKELY(!r)) {
MOZ_CRASH("Allocation or other failure while appending integers");
}
}
template <typename T>
void nsTSubstring<T>::AppendIntDec(uint64_t aInteger) {
PrintfAppend<T> appender(this);
bool r = appender.appendIntDec(aInteger);
if (MOZ_UNLIKELY(!r)) {
MOZ_CRASH("Allocation or other failure while appending integers");
}
}
template <typename T>
void nsTSubstring<T>::AppendIntOct(uint64_t aInteger) {
PrintfAppend<T> appender(this);
bool r = appender.appendIntOct(aInteger);
if (MOZ_UNLIKELY(!r)) {
MOZ_CRASH("Allocation or other failure while appending integers");
}
}
template <typename T>
void nsTSubstring<T>::AppendIntHex(uint64_t aInteger) {
PrintfAppend<T> appender(this);
bool r = appender.appendIntHex(aInteger);
if (MOZ_UNLIKELY(!r)) {
MOZ_CRASH("Allocation or other failure while appending integers");
}
}
// Returns the length of the formatted aDouble in aBuf.
static int FormatWithoutTrailingZeros(char (&aBuf)[40], double aDouble,
int aPrecision) {
static const DoubleToStringConverter converter(
DoubleToStringConverter::UNIQUE_ZERO |
DoubleToStringConverter::NO_TRAILING_ZERO |
DoubleToStringConverter::EMIT_POSITIVE_EXPONENT_SIGN,
"Infinity", "NaN", 'e', -6, 21, 6, 1);
double_conversion::StringBuilder builder(aBuf, sizeof(aBuf));
converter.ToPrecision(aDouble, aPrecision, &builder);
int length = builder.position();
builder.Finalize();
return length;
}
template <typename T>
void nsTSubstring<T>::AppendFloat(float aFloat) {
char buf[40];
int length = FormatWithoutTrailingZeros(buf, aFloat, 6);
AppendASCII(buf, length);
}
template <typename T>
void nsTSubstring<T>::AppendFloat(double aFloat) {
char buf[40];
int length = FormatWithoutTrailingZeros(buf, aFloat, 15);
AppendASCII(buf, length);
}
template <typename T>
size_t nsTSubstring<T>::SizeOfExcludingThisIfUnshared(
mozilla::MallocSizeOf aMallocSizeOf) const {
if (this->mDataFlags & DataFlags::REFCOUNTED) {
return mozilla::StringBuffer::FromData(this->mData)
->SizeOfIncludingThisIfUnshared(aMallocSizeOf);
}
if (this->mDataFlags & DataFlags::OWNED) {
return aMallocSizeOf(this->mData);
}
// If we reach here, exactly one of the following must be true:
// - DataFlags::VOIDED is set, and this->mData points to sEmptyBuffer;
// - DataFlags::INLINE is set, and this->mData points to a buffer within a
// string object (e.g. nsAutoString);
// - None of DataFlags::REFCOUNTED, DataFlags::OWNED, DataFlags::INLINE is
// set, and this->mData points to a buffer owned by something else.
//
// In all three cases, we don't measure it.
return 0;
}
template <typename T>
size_t nsTSubstring<T>::SizeOfExcludingThisEvenIfShared(
mozilla::MallocSizeOf aMallocSizeOf) const {
// This is identical to SizeOfExcludingThisIfUnshared except for the
// DataFlags::REFCOUNTED case.
if (this->mDataFlags & DataFlags::REFCOUNTED) {
return mozilla::StringBuffer::FromData(this->mData)
->SizeOfIncludingThisEvenIfShared(aMallocSizeOf);
}
if (this->mDataFlags & DataFlags::OWNED) {
return aMallocSizeOf(this->mData);
}
return 0;
}
template <typename T>
size_t nsTSubstring<T>::SizeOfIncludingThisIfUnshared(
mozilla::MallocSizeOf aMallocSizeOf) const {
return aMallocSizeOf(this) + SizeOfExcludingThisIfUnshared(aMallocSizeOf);
}
template <typename T>
size_t nsTSubstring<T>::SizeOfIncludingThisEvenIfShared(
mozilla::MallocSizeOf aMallocSizeOf) const {
return aMallocSizeOf(this) + SizeOfExcludingThisEvenIfShared(aMallocSizeOf);
}
template <typename T>
nsTSubstringSplitter<T> nsTSubstring<T>::Split(const char_type aChar) const {
return nsTSubstringSplitter<T>(
nsTCharSeparatedTokenizerTemplate<
NS_TokenizerIgnoreNothing, T,
nsTokenizerFlags::IncludeEmptyTokenAtEnd>(*this, aChar));
}
// Common logic for nsTSubstring<T>::ToInteger and nsTSubstring<T>::ToInteger64.
template <typename T, typename int_type>
int_type ToIntegerCommon(const nsTSubstring<T>& aSrc, nsresult* aErrorCode,
uint32_t aRadix) {
MOZ_ASSERT(aRadix == 10 || aRadix == 16);
// Initial value, override if we find an integer.
*aErrorCode = NS_ERROR_ILLEGAL_VALUE;
// Begin by skipping over leading chars that shouldn't be part of the number.
auto cp = aSrc.BeginReading();
auto endcp = aSrc.EndReading();
bool negate = false;
bool done = false;
// NB: For backwards compatibility I'm not going to change this logic but
// it seems really odd. Previously there was logic to auto-detect the
// radix if kAutoDetect was passed in. In practice this value was never
// used, so it pretended to auto detect and skipped some preceding
// letters (excluding valid hex digits) but never used the result.
//
// For example if you pass in "Get the number: 10", aRadix = 10 we'd
// skip the 'G', and then fail to parse "et the number: 10". If aRadix =
// 16 we'd skip the 'G', and parse just 'e' returning 14.
while ((cp < endcp) && (!done)) {
switch (*cp++) {
// clang-format off
case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
done = true;
break;
// clang-format on
case '-':
if constexpr (!std::is_signed_v<int_type>) {
return 0;
}
negate = true;
break;
default:
break;
}
}
if (!done) {
// No base 16 or base 10 digits were found.
return 0;
}
// Step back.
cp--;
mozilla::CheckedInt<int_type> result;
// Now iterate the numeric chars and build our result.
while (cp < endcp) {
auto theChar = *cp++;
if (('0' <= theChar) && (theChar <= '9')) {
result = (aRadix * result) + (theChar - '0');
} else if ((theChar >= 'A') && (theChar <= 'F')) {
if (10 == aRadix) {
// Invalid base 10 digit, error out.
return 0;
}
result = (aRadix * result) + ((theChar - 'A') + 10);
} else if ((theChar >= 'a') && (theChar <= 'f')) {
if (10 == aRadix) {
// Invalid base 10 digit, error out.
return 0;
}
result = (aRadix * result) + ((theChar - 'a') + 10);
} else if ((('X' == theChar) || ('x' == theChar)) && result == 0) {
// For some reason we support a leading 'x' regardless of radix. For
// example: "000000x500", aRadix = 10 would be parsed as 500 rather
// than 0.
continue;
} else {
// We've encountered a char that's not a legal number or sign and we can
// terminate processing.
break;
}
if (!result.isValid()) {
// Overflow!
return 0;
}
}
// Integer found.
*aErrorCode = NS_OK;
if (negate) {
result = -result;
}
return result.value();
}
template <typename T>
int32_t nsTSubstring<T>::ToInteger(nsresult* aErrorCode,
uint32_t aRadix) const {
return ToIntegerCommon<T, int32_t>(*this, aErrorCode, aRadix);
}
template <typename T>
uint32_t nsTSubstring<T>::ToUnsignedInteger(nsresult* aErrorCode,
uint32_t aRadix) const {
return ToIntegerCommon<T, uint32_t>(*this, aErrorCode, aRadix);
}
/**
* nsTSubstring::ToInteger64
*/
template <typename T>
int64_t nsTSubstring<T>::ToInteger64(nsresult* aErrorCode,
uint32_t aRadix) const {
return ToIntegerCommon<T, int64_t>(*this, aErrorCode, aRadix);
}
/**
* nsTSubstring::Mid
*/
template <typename T>
typename nsTSubstring<T>::size_type nsTSubstring<T>::Mid(
self_type& aResult, index_type aStartPos, size_type aLengthToCopy) const {
if (aStartPos == 0 && aLengthToCopy >= this->mLength) {
aResult = *this;
} else {
aResult = Substring(*this, aStartPos, aLengthToCopy);
}
return aResult.mLength;
}
/**
* nsTSubstring::StripWhitespace
*/
template <typename T>
void nsTSubstring<T>::StripWhitespace() {
if (!StripWhitespace(mozilla::fallible)) {
this->AllocFailed(this->mLength);
}
}
template <typename T>
bool nsTSubstring<T>::StripWhitespace(const fallible_t&) {
if (!this->EnsureMutable()) {
return false;
}
this->StripTaggedASCII(mozilla::ASCIIMask::MaskWhitespace());
return true;
}
/**
* nsTSubstring::ReplaceChar,ReplaceSubstring
*/
template <typename T>
void nsTSubstring<T>::ReplaceChar(char_type aOldChar, char_type aNewChar) {
int32_t i = this->FindChar(aOldChar);
if (i == kNotFound) {
return;
}
if (!this->EnsureMutable()) {
this->AllocFailed(this->mLength);
}
for (; i != kNotFound; i = this->FindChar(aOldChar, i + 1)) {
this->mData[i] = aNewChar;
}
}
template <typename T>
void nsTSubstring<T>::ReplaceChar(const string_view& aSet, char_type aNewChar) {
int32_t i = this->FindCharInSet(aSet);
if (i == kNotFound) {
return;
}
if (!this->EnsureMutable()) {
this->AllocFailed(this->mLength);
}
for (; i != kNotFound; i = this->FindCharInSet(aSet, i + 1)) {
this->mData[i] = aNewChar;
}
}
template <typename T>
void nsTSubstring<T>::ReplaceSubstring(const char_type* aTarget,
const char_type* aNewValue) {
ReplaceSubstring(nsTDependentString<T>(aTarget),
nsTDependentString<T>(aNewValue));
}
template <typename T>
bool nsTSubstring<T>::ReplaceSubstring(const char_type* aTarget,
const char_type* aNewValue,
const fallible_t& aFallible) {
return ReplaceSubstring(nsTDependentString<T>(aTarget),
nsTDependentString<T>(aNewValue), aFallible);
}
template <typename T>
void nsTSubstring<T>::ReplaceSubstring(const self_type& aTarget,
const self_type& aNewValue) {
if (!ReplaceSubstring(aTarget, aNewValue, mozilla::fallible)) {
// Note that this may wildly underestimate the allocation that failed, as
// we could have been replacing multiple copies of aTarget.
this->AllocFailed(this->mLength + (aNewValue.Length() - aTarget.Length()));
}
}
template <typename T>
bool nsTSubstring<T>::ReplaceSubstring(const self_type& aTarget,
const self_type& aNewValue,
const fallible_t&) {
struct Segment {
uint32_t mBegin, mLength;
Segment(uint32_t aBegin, uint32_t aLength)
: mBegin(aBegin), mLength(aLength) {}
};
if (aTarget.Length() == 0) {
return true;
}
// Remember all of the non-matching parts.
AutoTArray<Segment, 16> nonMatching;
uint32_t i = 0;
mozilla::CheckedUint32 newLength;
while (true) {
int32_t r = this->Find(aTarget, i);
int32_t until = (r == kNotFound) ? this->Length() - i : r - i;
nonMatching.AppendElement(Segment(i, until));
newLength += until;
if (r == kNotFound) {
break;
}
newLength += aNewValue.Length();
i = r + aTarget.Length();
if (i >= this->Length()) {
// Add an auxiliary entry at the end of the list to help as an edge case
// for the algorithms below.
nonMatching.AppendElement(Segment(this->Length(), 0));
break;
}
}
if (!newLength.isValid()) {
return false;
}
// If there's only one non-matching segment, then the target string was not
// found, and there's nothing to do.
if (nonMatching.Length() == 1) {
MOZ_ASSERT(
nonMatching[0].mBegin == 0 && nonMatching[0].mLength == this->Length(),
"We should have the correct non-matching segment.");
return true;
}
// Make sure that we can mutate our buffer.
// Note that we always allocate at least an this->mLength sized buffer,
// because the rest of the algorithm relies on having access to all of the
// original string. In other words, we over-allocate in the shrinking case.
uint32_t oldLen = this->Length();
auto r =
this->StartBulkWriteImpl(XPCOM_MAX(oldLen, newLength.value()), oldLen);
if (r.isErr()) {
return false;
}
if (aTarget.Length() >= aNewValue.Length()) {
// In the shrinking case, start filling the buffer from the beginning.
const uint32_t delta = (aTarget.Length() - aNewValue.Length());
for (i = 1; i < nonMatching.Length(); ++i) {
// When we move the i'th non-matching segment into position, we need to
// account for the characters deleted by the previous |i| replacements by
// subtracting |i * delta|.
const char_type* sourceSegmentPtr = this->mData + nonMatching[i].mBegin;
char_type* destinationSegmentPtr =
this->mData + nonMatching[i].mBegin - i * delta;
// Write the i'th replacement immediately before the new i'th non-matching
// segment.
char_traits::copy(destinationSegmentPtr - aNewValue.Length(),
aNewValue.Data(), aNewValue.Length());
char_traits::move(destinationSegmentPtr, sourceSegmentPtr,
nonMatching[i].mLength);
}
} else {
// In the growing case, start filling the buffer from the end.
const uint32_t delta = (aNewValue.Length() - aTarget.Length());
for (i = nonMatching.Length() - 1; i > 0; --i) {
// When we move the i'th non-matching segment into position, we need to
// account for the characters added by the previous |i| replacements by
// adding |i * delta|.
const char_type* sourceSegmentPtr = this->mData + nonMatching[i].mBegin;
char_type* destinationSegmentPtr =
this->mData + nonMatching[i].mBegin + i * delta;
char_traits::move(destinationSegmentPtr, sourceSegmentPtr,
nonMatching[i].mLength);
// Write the i'th replacement immediately before the new i'th non-matching
// segment.
char_traits::copy(destinationSegmentPtr - aNewValue.Length(),
aNewValue.Data(), aNewValue.Length());
}
}
// Adjust the length and make sure the string is null terminated.
this->FinishBulkWriteImpl(newLength.value());
return true;
}
/**
* nsTSubstring::Trim
*/
template <typename T>
void nsTSubstring<T>::Trim(const std::string_view& aSet, bool aTrimLeading,
bool aTrimTrailing, bool aIgnoreQuotes) {
char_type* start = this->mData;
char_type* end = this->mData + this->mLength;
// skip over quotes if requested
if (aIgnoreQuotes && this->mLength > 2 &&
this->mData[0] == this->mData[this->mLength - 1] &&
(this->mData[0] == '\'' || this->mData[0] == '"')) {
++start;
--end;
}
if (aTrimLeading) {
uint32_t cutStart = start - this->mData;
uint32_t cutLength = 0;
// walk forward from start to end
for (; start != end; ++start, ++cutLength) {
if ((*start & ~0x7F) || // non-ascii
aSet.find(char(*start)) == std::string_view::npos) {
break;
}
}
if (cutLength) {
this->Cut(cutStart, cutLength);
// reset iterators
start = this->mData + cutStart;
end = this->mData + this->mLength - cutStart;
}
}
if (aTrimTrailing) {
uint32_t cutEnd = end - this->mData;
uint32_t cutLength = 0;
// walk backward from end to start
--end;
for (; end >= start; --end, ++cutLength) {
if ((*end & ~0x7F) || // non-ascii
aSet.find(char(*end)) == std::string_view::npos) {
break;
}
}
if (cutLength) {
this->Cut(cutEnd - cutLength, cutLength);
}
}
}
/**
* nsTSubstring::CompressWhitespace.
*/
template <typename T>
void nsTSubstring<T>::CompressWhitespace(bool aTrimLeading,
bool aTrimTrailing) {
// Quick exit
if (this->mLength == 0) {
return;
}
if (!this->EnsureMutable()) {
this->AllocFailed(this->mLength);
}
const ASCIIMaskArray& mask = mozilla::ASCIIMask::MaskWhitespace();
char_type* to = this->mData;
char_type* from = this->mData;
char_type* end = this->mData + this->mLength;
// Compresses runs of whitespace down to a normal space ' ' and convert
// any whitespace to a normal space. This assumes that whitespace is
// all standard 7-bit ASCII.
bool skipWS = aTrimLeading;
while (from < end) {
uint32_t theChar = *from++;
if (mozilla::ASCIIMask::IsMasked(mask, theChar)) {
if (!skipWS) {
*to++ = ' ';
skipWS = true;
}
} else {
*to++ = theChar;
skipWS = false;
}
}
// If we need to trim the trailing whitespace, back up one character.
if (aTrimTrailing && skipWS && to > this->mData) {
to--;
}
*to = char_type(0); // add the null
this->mLength = to - this->mData;
}
template class nsTSubstring<char>;
template class nsTSubstring<char16_t>;
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