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BString: rewrite cleanup methods

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This removes the use of the destructor in the move assignment operator, as it
may rely on undefined behaviour from the compiler. Additionally, some duplicate
logic to dereference and free a shared string has been unified under
_ReleasePrivateData().

Change-Id: Ie9f51d598c734f83cd0fba49b651315c6e9c8aac
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4440
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
This commit is contained in:
Niels Sascha Reedijk 2021-09-09 22:28:10 +01:00
parent 6da19c9e40
commit 530f89aa6d
2 changed files with 15 additions and 21 deletions
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1
headers/os/support/String.h
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@ -423,6 +423,7 @@ private:
const int32& _ReferenceCount() const;
bool _IsShareable() const;
void _FreePrivateData();
void _ReleasePrivateData();
char* fPrivateData;
};

35
src/kits/support/String.cpp
View File

@ -204,8 +204,7 @@ BString::BString(BString&& string)
BString::~BString()
{
if (!_IsShareable() || atomic_add(&_ReferenceCount(), -1) == 1)
_FreePrivateData();
_ReleasePrivateData();
}
@ -277,8 +276,7 @@ BString&
BString::operator=(BString&& string)
{
if (this != &string) {
this->~BString();
// free up any resources allocated by the current contents
_ReleasePrivateData();
fPrivateData = string.fPrivateData;
string.fPrivateData = NULL;
}
@ -309,15 +307,7 @@ BString::SetTo(const BString& string)
if (fPrivateData == string.fPrivateData)
return *this;
bool freeData = true;
if (_IsShareable() && atomic_add(&_ReferenceCount(), -1) > 1) {
// there is still someone who shares our data
freeData = false;
}
if (freeData)
_FreePrivateData();
_ReleasePrivateData();
// if source is sharable share, otherwise clone
if (string._IsShareable()) {
@ -2293,10 +2283,7 @@ BString::_MakeWritable()
if (atomic_get(&_ReferenceCount()) > 1) {
// It might be shared, and this requires special treatment
char* newData = _Clone(fPrivateData, Length());
if (atomic_add(&_ReferenceCount(), -1) == 1) {
// someone else left, we were the last owner
_FreePrivateData();
}
_ReleasePrivateData();
if (newData == NULL)
return B_NO_MEMORY;
@ -2328,10 +2315,7 @@ BString::_MakeWritable(int32 length, bool copy)
if (newData == NULL)
return B_NO_MEMORY;
if (atomic_add(&_ReferenceCount(), -1) == 1) {
// someone else left, we were the last owner
_FreePrivateData();
}
_ReleasePrivateData();
} else {
// we don't share our data with someone else
newData = _Resize(length);
@ -2469,6 +2453,15 @@ BString::_FreePrivateData()
}
void
BString::_ReleasePrivateData()
{
if (!_IsShareable() || atomic_add(&_ReferenceCount(), -1) == 1)
_FreePrivateData();
fPrivateData = NULL;
}
bool
BString::_DoAppend(const char* string, int32 length)
{