nsTAdoptingString_CharT&
nsTAdoptingString_CharT::operator=(const self_type& str)
{
// This'll violate the constness of this argument, that's just
// the nature of this class...
self_type* mutable_str = const_cast<self_type*>(&str);
if (str.mFlags & F_OWNED) {
// We want to do what Adopt() does, but without actually incrementing
// the Adopt count. Note that we can be a little more straightforward
// about this than Adopt() is, because we know that str.mData is
// non-null. Should we be able to assert that str is not void here?
NS_ASSERTION(str.mData, "String with null mData?");
Finalize();
mData = str.mData;
mLength = str.mLength;
SetDataFlags(F_TERMINATED | F_OWNED);
// Make str forget the buffer we just took ownership of.
new(mutable_str) self_type();
} else {
Assign(str);
mutable_str->Truncate();
}
return *this;
}
void
nsTSubstring_CharT::Adopt( char_type* data, size_type length )
{
if (data)
{
::ReleaseData(mData, mFlags);
if (length == size_type(-1))
length = char_traits::length(data);
mData = data;
mLength = length;
SetDataFlags(F_TERMINATED | F_OWNED);
STRING_STAT_INCREMENT(Adopt);
#ifdef NS_BUILD_REFCNT_LOGGING
// Treat this as construction of a "StringAdopt" object for leak
// tracking purposes.
NS_LogCtor(mData, "StringAdopt", 1);
#endif // NS_BUILD_REFCNT_LOGGING
}
else
{
SetIsVoid(true);
}
}
void
nsTDependentString_CharT::Rebind( const char_type* data, size_type length )
{
// If we currently own a buffer, release it.
Finalize();
mData = const_cast<char_type*>(data);
mLength = length;
SetDataFlags(F_TERMINATED);
AssertValid();
}
void
nsTDependentSubstring_CharT::Rebind( const char_type* data, size_type length )
{
NS_ASSERTION(data, "nsTDependentSubstring must wrap a non-NULL buffer");
// If we currently own a buffer, release it.
Finalize();
mData = const_cast<char_type*>(static_cast<const char_type*>(data));
mLength = length;
SetDataFlags(F_NONE);
}
void
nsTDependentSubstring_CharT::Rebind( const char_type* start, const char_type* end )
{
NS_ASSERTION(start && end, "nsTDependentSubstring must wrap a non-NULL buffer");
// If we currently own a buffer, release it.
Finalize();
mData = NS_CONST_CAST(char_type*, start);
mLength = end - start;
SetDataFlags(F_NONE);
}
void
nsTDependentString_CharT::Rebind( const string_type& str, PRUint32 startPos )
{
// If we currently own a buffer, release it.
Finalize();
size_type strLength = str.Length();
if (startPos > strLength)
startPos = strLength;
mData = const_cast<char_type*>(str.Data()) + startPos;
mLength = strLength - startPos;
SetDataFlags(F_TERMINATED);
}
void
nsTDependentSubstring_CharT::Rebind( const substring_type& str, uint32_t startPos, uint32_t length )
{
// If we currently own a buffer, release it.
Finalize();
size_type strLength = str.Length();
if (startPos > strLength)
startPos = strLength;
mData = const_cast<char_type*>(static_cast<const char_type*>(str.Data())) + startPos;
mLength = XPCOM_MIN(length, strLength - startPos);
SetDataFlags(F_NONE);
}
void
nsTDependentSubstring_CharT::Rebind( const substring_type& str, PRUint32 startPos, PRUint32 length )
{
// If we currently own a buffer, release it.
Finalize();
size_type strLength = str.Length();
if (startPos > strLength)
startPos = strLength;
mData = NS_CONST_CAST(char_type*, str.Data()) + startPos;
mLength = NS_MIN(length, strLength - startPos);
SetDataFlags(F_NONE);
}
void
nsTDependentSubstring_CharT::Rebind( const abstract_string_type& readable, PRUint32 startPos, PRUint32 length )
{
// If we currently own a buffer, release it.
Finalize();
size_type strLength = readable.GetReadableBuffer((const char_type**) &mData);
if (startPos > strLength)
startPos = strLength;
mData += startPos;
mLength = NS_MIN(length, strLength - startPos);
SetDataFlags(F_NONE);
}
PRBool
nsTSubstring_CharT::SetCapacity( size_type capacity )
{
// capacity does not include room for the terminating null char
// if our capacity is reduced to zero, then free our buffer.
if (capacity == 0)
{
::ReleaseData(mData, mFlags);
mData = char_traits::sEmptyBuffer;
mLength = 0;
SetDataFlags(F_TERMINATED);
}
else
{
char_type* oldData;
PRUint32 oldFlags;
if (!MutatePrep(capacity, &oldData, &oldFlags))
return PR_FALSE; // out-of-memory
// compute new string length
size_type newLen = NS_MIN(mLength, capacity);
if (oldData)
{
// preserve old data
if (mLength > 0)
char_traits::copy(mData, oldData, newLen);
::ReleaseData(oldData, oldFlags);
}
// adjust mLength if our buffer shrunk down in size
if (newLen < mLength)
mLength = newLen;
// always null-terminate here, even if the buffer got longer. this is
// for backwards compat with the old string implementation.
mData[capacity] = char_type(0);
}
return PR_TRUE;
}
void
nsTDependentString_CharT::Rebind(const string_type& str, uint32_t startPos)
{
NS_ABORT_IF_FALSE(str.Flags() & F_TERMINATED, "Unterminated flat string");
// If we currently own a buffer, release it.
Finalize();
size_type strLength = str.Length();
if (startPos > strLength) {
startPos = strLength;
}
mData = const_cast<char_type*>(static_cast<const char_type*>(str.Data())) + startPos;
mLength = strLength - startPos;
SetDataFlags(str.Flags() & (F_TERMINATED | F_LITERAL));
}
bool
nsTSubstring_CharT::Assign( const self_type& str, const fallible_t& )
{
// |str| could be sharable. we need to check its flags to know how to
// deal with it.
if (&str == this)
return true;
if (!str.mLength)
{
Truncate();
mFlags |= str.mFlags & F_VOIDED;
return true;
}
if (str.mFlags & F_SHARED)
{
// nice! we can avoid a string copy :-)
// |str| should be null-terminated
NS_ASSERTION(str.mFlags & F_TERMINATED, "shared, but not terminated");
::ReleaseData(mData, mFlags);
mData = str.mData;
mLength = str.mLength;
SetDataFlags(F_TERMINATED | F_SHARED);
// get an owning reference to the mData
nsStringBuffer::FromData(mData)->AddRef();
return true;
}
// else, treat this like an ordinary assignment.
return Assign(str.Data(), str.Length(), fallible_t());
}
/**
* this function is called to prepare mData for writing. the given capacity
* indicates the required minimum storage size for mData, in sizeof(char_type)
* increments. this function returns true if the operation succeeds. it also
* returns the old data and old flags members if mData is newly allocated.
* the old data must be released by the caller.
*/
bool
nsTSubstring_CharT::MutatePrep( size_type capacity, char_type** oldData, uint32_t* oldFlags )
{
// initialize to no old data
*oldData = nullptr;
*oldFlags = 0;
size_type curCapacity = Capacity();
// If |capacity > 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.
PR_STATIC_ASSERT((sizeof(nsStringBuffer) & 0x1) == 0);
const size_type kMaxCapacity =
(size_type(-1)/2 - sizeof(nsStringBuffer)) / sizeof(char_type) - 2;
if (capacity > kMaxCapacity) {
// Also assert for |capacity| equal to |size_type(-1)|, since we used to
// use that value to flag immutability.
NS_ASSERTION(capacity != size_type(-1), "Bogus capacity");
return false;
}
// |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 (curCapacity != 0)
{
if (capacity <= curCapacity) {
mFlags &= ~F_VOIDED; // mutation clears voided flag
return true;
}
// Use doubling algorithm when forced to increase available capacity.
size_type temp = curCapacity;
while (temp < capacity)
temp <<= 1;
NS_ASSERTION(XPCOM_MIN(temp, kMaxCapacity) >= capacity,
"should have hit the early return at the top");
capacity = XPCOM_MIN(temp, kMaxCapacity);
}
//
// several cases:
//
// (1) we have a shared buffer (mFlags & F_SHARED)
// (2) we have an owned buffer (mFlags & F_OWNED)
// (3) we have a fixed buffer (mFlags & F_FIXED)
// (4) we have a readonly buffer
//
// requiring that we in some cases preserve the data before creating
// a new buffer complicates things just a bit ;-)
//
size_type storageSize = (capacity + 1) * sizeof(char_type);
// case #1
if (mFlags & F_SHARED)
{
nsStringBuffer* hdr = nsStringBuffer::FromData(mData);
if (!hdr->IsReadonly())
{
nsStringBuffer *newHdr = nsStringBuffer::Realloc(hdr, storageSize);
if (!newHdr)
return false; // out-of-memory (original header left intact)
hdr = newHdr;
mData = (char_type*) hdr->Data();
mFlags &= ~F_VOIDED; // mutation clears voided flag
return true;
}
}
char_type* newData;
uint32_t newDataFlags;
// if we have a fixed buffer of sufficient size, then use it. this helps
// avoid heap allocations.
if ((mFlags & F_CLASS_FIXED) && (capacity < AsFixedString(this)->mFixedCapacity))
{
newData = AsFixedString(this)->mFixedBuf;
newDataFlags = F_TERMINATED | F_FIXED;
}
else
{
// if we reach here then, we must allocate a new buffer. we cannot
// make use of our F_OWNED or F_FIXED buffers because they are not
// large enough.
nsStringBuffer* newHdr = nsStringBuffer::Alloc(storageSize);
if (!newHdr)
return false; // we are still in a consistent state
newData = (char_type*) newHdr->Data();
newDataFlags = F_TERMINATED | F_SHARED;
}
// save old data and flags
*oldData = mData;
*oldFlags = mFlags;
mData = newData;
SetDataFlags(newDataFlags);
// mLength does not change
// though we are not necessarily terminated at the moment, now is probably
// still the best time to set F_TERMINATED.
return true;
}
/**
* this function is called to prepare mData for writing. the given capacity
* indicates the required minimum storage size for mData, in sizeof(char_type)
* increments. this function returns true if the operation succeeds. it also
* returns the old data and old flags members if mData is newly allocated.
* the old data must be released by the caller.
*/
PRBool
nsTSubstring_CharT::MutatePrep( size_type capacity, char_type** oldData, PRUint32* oldFlags )
{
// initialize to no old data
*oldData = nsnull;
*oldFlags = 0;
size_type curCapacity = Capacity();
// |curCapacity == size_type(-1)| means that the buffer is immutable, so we
// need to allocate a new buffer. we cannot use the existing buffer even
// though it might be large enough.
if (curCapacity != size_type(-1))
{
if (capacity <= curCapacity)
return PR_TRUE;
if (curCapacity > 0)
{
// use doubling algorithm when forced to increase available capacity,
// but always start out with exactly the requested amount.
PRUint32 temp = curCapacity;
while (temp < capacity)
temp <<= 1;
capacity = temp;
}
}
//
// several cases:
//
// (1) we have a shared buffer (mFlags & F_SHARED)
// (2) we have an owned buffer (mFlags & F_OWNED)
// (3) we have a fixed buffer (mFlags & F_FIXED)
// (4) we have a readonly buffer
//
// requiring that we in some cases preserve the data before creating
// a new buffer complicates things just a bit ;-)
//
size_type storageSize = (capacity + 1) * sizeof(char_type);
// case #1
if (mFlags & F_SHARED)
{
nsStringHeader* hdr = nsStringHeader::FromData(mData);
if (!hdr->IsReadonly())
{
nsStringHeader *newHdr = nsStringHeader::Realloc(hdr, storageSize);
if (newHdr)
{
hdr = newHdr;
mData = (char_type*) hdr->Data();
return PR_TRUE;
}
hdr->Release();
// out of memory!! put us in a consistent state at least.
mData = NS_CONST_CAST(char_type*, char_traits::sEmptyBuffer);
mLength = 0;
SetDataFlags(F_TERMINATED);
return PR_FALSE;
}
