lf_queue: add range-for support (endless loop with waiting)

Utilities/lockless.h

@@ -401,6 +401,64 @@ public:
 
 		return count;
 	}
+
+	// Iterator that enables direct endless range-for loop: for (auto* ptr : queue) ...
+	class iterator
+	{
+		lf_queue* _this = nullptr;
+
+		lf_queue_slice<T> m_data;
+
+	public:
+		constexpr iterator() = default;
+
+		explicit iterator(lf_queue* _this)
+			: _this(_this)
+		{
+			m_data = _this->pop_all();
+		}
+
+		bool operator !=(const iterator& rhs) const
+		{
+			return _this != rhs._this;
+		}
+
+		T* operator *() const
+		{
+			return m_data ? m_data.get() : nullptr;
+		}
+
+		iterator& operator ++()
+		{
+			if (m_data)
+			{
+				m_data.pop_front();
+			}
+
+			if (!m_data)
+			{
+				m_data = _this->pop_all();
+
+				if (!m_data)
+				{
+					_this->wait();
+					m_data = _this->pop_all();
+				}
+			}
+
+			return *this;
+		}
+	};
+
+	iterator begin()
+	{
+		return iterator{this};
+	}
+
+	iterator end()
+	{
+		return iterator{};
+	}
 };
 
 // Assignable lock-free thread-safe value of any type (memory-inefficient)

rpcs3/Emu/Cell/Modules/cellVdec.cpp

@@ -180,15 +180,14 @@ struct vdec_context final
 	{
 		ppu_tid = ppu.id;
 
-		for (auto cmds = in_cmd.pop_all(); thread_ctrl::state() != thread_state::aborting; cmds ? cmds.pop_front() : cmds = in_cmd.pop_all())
+		// pcmd can be nullptr
+		for (auto* pcmd : in_cmd)
 		{
-			if (!cmds)
+			if (thread_ctrl::state() == thread_state::aborting)
 			{
-				in_cmd.wait();
-				continue;
+				break;
 			}
-
-			if (std::get_if<vdec_start_seq_t>(&*cmds))
+			else if (std::get_if<vdec_start_seq_t>(pcmd))
 			{
 				avcodec_flush_buffers(ctx);
 
@@ -197,7 +196,7 @@ struct vdec_context final
 				next_dts = 0;
 				cellVdec.trace("Start sequence...");
 			}
-			else if (auto* cmd = std::get_if<vdec_cmd>(&*cmds))
+			else if (auto* cmd = std::get_if<vdec_cmd>(pcmd))
 			{
 				AVPacket packet{};
 				packet.pos = -1;
@@ -399,11 +398,11 @@ struct vdec_context final
 					thread_ctrl::wait_for(1000);
 				}
 			}
-			else if (auto* frc = std::get_if<CellVdecFrameRate>(&*cmds))
+			else if (auto* frc = std::get_if<CellVdecFrameRate>(pcmd))
 			{
 				frc_set = *frc;
 			}
-			else
+			else if (std::get_if<vdec_close_t>(pcmd))
 			{
 				break;
 			}