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Description: Remove default constructor implementation
vcow_ptr is a rlottie-specific implementation of the shared pointer.
It provides a default constructor containing a static variable that is
potentially deleted in the destructor. Remove constructor implementation in
order to avoid undefined behavior.
Author: Vladimir Petko <vladimir.petko@canonical.com>
Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1032481
Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/rlottie/+bug/2009551
Last-Update: 2023-03-07
--- a/src/vector/vcowptr.h
+++ b/src/vector/vcowptr.h
@@ -35,21 +35,18 @@
T mValue;
};
- model* mModel;
-
+ model* mModel{};
public:
using element_type = T;
- vcow_ptr()
- {
- static model default_s;
- mModel = &default_s;
- ++mModel->mRef;
- }
+ vcow_ptr() = default;
~vcow_ptr()
{
- if (mModel && (--mModel->mRef == 0)) delete mModel;
+ if (mModel && (--mModel->mRef == 0)) {
+ delete mModel;
+ mModel = nullptr;
+ }
}
template <class... Args>
@@ -59,12 +56,14 @@
vcow_ptr(const vcow_ptr& x) noexcept : mModel(x.mModel)
{
- assert(mModel);
+ if (mModel == nullptr)
+ return;
++mModel->mRef;
}
vcow_ptr(vcow_ptr&& x) noexcept : mModel(x.mModel)
{
- assert(mModel);
+ if (mModel == nullptr)
+ return;
x.mModel = nullptr;
}
@@ -87,14 +86,16 @@
std::size_t refCount() const noexcept
{
- assert(mModel);
+ if (mModel == nullptr)
+ return 0;
return mModel->mRef;
}
bool unique() const noexcept
{
- assert(mModel);
+ if (mModel == nullptr)
+ return false;
return mModel->mRef == 1;
}
@@ -103,12 +104,15 @@
{
if (!unique()) *this = vcow_ptr(read());
+ assert(mModel);
return mModel->mValue;
}
auto read() const noexcept -> const element_type&
{
- assert(mModel);
+ static model default_s{};
+ if (mModel == nullptr)
+ return default_s.mValue;
return mModel->mValue;
}
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