124 lines
3.3 KiB
C++
124 lines
3.3 KiB
C++
/*
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OpenPnp-Capture: a video capture subsystem.
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Scoped COM pointer to auto-release the object
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when it goes out of scope
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Copyright (c) 2017 Niels Moseley.
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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#ifndef win_scopedcomptr_h
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#define win_scopedcomptr_h
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/** The ScopedComPtr takes a pointer to a generic COM
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interface object and will release the object when
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the owning ScopedComPtr is released/destroyed.
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Example:
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sampleGrabberPointer = .. create ISampleGrabber via COM
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ScopedComPtr<ISampleGrabber> sampleGrabber(sampleGrabberPointer);
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.. code ..
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if (error)
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{
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return; // this will automatically release ISampleGrabber
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}
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If the pointer handled by ScopedComPtr needs to be returned
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from a function, the Detach() method will transfer ownership.
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*/
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template <typename Interface> class ScopedComPtr
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{
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public:
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/** create a ScopedComPtr object and take ownership of
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the Interface object/pointer */
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ScopedComPtr(Interface* ptr) : m_ptr(ptr)
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{
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}
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/** destroy the ScopedComPtr object and
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release the associated Interface pointer */
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~ScopedComPtr()
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{
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if (m_ptr != nullptr)
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{
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InternalRelease();
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}
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}
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/** access methods exposed by Interface */
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Interface* operator->() const
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{
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return m_ptr;
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}
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/** replace the internal pointer with a new one,
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the old object is released/destroyed */
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void Replace(Interface *newPtr)
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{
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InternalRelease();
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m_ptr = newPtr;
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}
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/** detach the object from the scoped pointer object
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without releasing it. */
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Interface* Detach()
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{
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Interface *obj = m_ptr;
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m_ptr = nullptr;
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return obj;
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}
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private:
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void InternalRelease()
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{
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Interface * temp = m_ptr;
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if (temp != nullptr)
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{
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m_ptr = nullptr;
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temp->Release();
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}
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}
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//disallow copying of a scoped pointer!
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ScopedComPtr(ScopedComPtr const & other)
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{
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}
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Interface *m_ptr = nullptr;
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};
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/** SafeRelease(ptr) check if the ptr isn't NULL.
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If it isn't it invokes the Release() method on it */
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template <class T> void SafeRelease(T **ppT)
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{
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if (*ppT)
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{
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(*ppT)->Release();
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*ppT = NULL;
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}
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}
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#endif |