Fix rule of three for SampleBuffer, SampleTCO (#5727)

* Automatic formatting changes

* Add copy constructor and assignemnt to SampleBuffer

* Add copy constructor to SampleTCO

* Delete SampleTCO copy assignment, initial work on SampleBuffer swap method

* SampleBuffer: Finish(?) swap and use it for copy assignment, lock for read in copy constructor

* Don't forget to unlock in copy assignment!

* Formatting changes

* Lock ordering in swap

* Fix leak and constness

Co-authored-by: Dominic Clark <mrdomclark@gmail.com>

* Fix multiplication style, ensure lock is held when necessary

... by switching from an initializer list to manual assignments.

* Fixes from review

* Avoid more undefined behavior

* Update src/tracks/SampleTrack.cpp

Co-authored-by: Dominic Clark <mrdomclark@gmail.com>

src/core/SampleBuffer.cpp

@@ -130,6 +130,86 @@ SampleBuffer::SampleBuffer(const f_cnt_t frames)
 
 
 
+SampleBuffer::SampleBuffer(const SampleBuffer& orig)
+{
+	orig.m_varLock.lockForRead();
+
+	m_audioFile = orig.m_audioFile;
+	m_origFrames = orig.m_origFrames;
+	m_origData = (m_origFrames > 0) ? MM_ALLOC(sampleFrame, m_origFrames) : nullptr;
+	m_frames = orig.m_frames;
+	m_data = (m_frames > 0) ? MM_ALLOC(sampleFrame, m_frames) : nullptr;
+	m_startFrame = orig.m_startFrame;
+	m_endFrame = orig.m_endFrame;
+	m_loopStartFrame = orig.m_loopStartFrame;
+	m_loopEndFrame = orig.m_loopEndFrame;
+	m_amplification = orig.m_amplification;
+	m_reversed = orig.m_reversed;
+	m_frequency = orig.m_frequency;
+	m_sampleRate = orig.m_sampleRate;
+
+	//Deep copy m_origData and m_data from original
+	const auto origFrameBytes = m_origFrames * BYTES_PER_FRAME;
+	const auto frameBytes = m_frames * BYTES_PER_FRAME;
+	if (orig.m_origData != nullptr && origFrameBytes > 0)
+		{ memcpy(m_origData, orig.m_origData, origFrameBytes); }
+	if (orig.m_data != nullptr && frameBytes > 0)
+		{ memcpy(m_data, orig.m_data, frameBytes); }
+
+	orig.m_varLock.unlock();
+}
+
+
+
+
+void swap(SampleBuffer& first, SampleBuffer& second) noexcept
+{
+	using std::swap;
+
+	// Lock both buffers for writing, with address as lock ordering
+	if (&first == &second) { return; }
+	else if (&first > &second)
+	{
+		first.m_varLock.lockForWrite();
+		second.m_varLock.lockForWrite();
+	}
+	else
+	{
+		second.m_varLock.lockForWrite();
+		first.m_varLock.lockForWrite();
+	}
+
+	first.m_audioFile.swap(second.m_audioFile);
+	swap(first.m_origData, second.m_origData);
+	swap(first.m_data, second.m_data);
+	swap(first.m_origFrames, second.m_origFrames);
+	swap(first.m_frames, second.m_frames);
+	swap(first.m_startFrame, second.m_startFrame);
+	swap(first.m_endFrame, second.m_endFrame);
+	swap(first.m_loopStartFrame, second.m_loopStartFrame);
+	swap(first.m_loopEndFrame, second.m_loopEndFrame);
+	swap(first.m_amplification, second.m_amplification);
+	swap(first.m_frequency, second.m_frequency);
+	swap(first.m_reversed, second.m_reversed);
+	swap(first.m_sampleRate, second.m_sampleRate);
+
+	// Unlock again
+	first.m_varLock.unlock();
+	second.m_varLock.unlock();
+}
+
+
+
+
+SampleBuffer& SampleBuffer::operator=(SampleBuffer that)
+{
+	swap(*this, that);
+	return *this;
+}
+
+
+
+
 SampleBuffer::~SampleBuffer()
 {
 	MM_FREE(m_origData);