d3d11memory: Add a method for querying texture array size

... and the number of textures in use.

Direct3D11 texture array is usually used for decoder DPB pool,
and d3d11 decoder elements might want to know
whether there's available texture resource or not.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2003>

gst-libs/gst/d3d11/gstd3d11memory.c

@@ -280,6 +280,10 @@ struct _GstD3D11AllocatorPrivate
   GArray *decoder_output_view_array;
   GArray *processor_input_view_array;
 
+  /* Count the number of array textures in use */
+  guint num_array_textures_in_use;
+  guint array_texture_size;
+
   GMutex lock;
   GCond cond;
 
@@ -551,6 +555,7 @@ gst_d3d11_allocator_free (GstAllocator * allocator, GstMemory * mem)
     GST_D3D11_ALLOCATOR_LOCK (self);
     g_array_index (priv->array_in_use,
         guint8, dmem_priv->subresource_index) = 0;
+    priv->num_array_textures_in_use--;
     g_cond_broadcast (&priv->cond);
     GST_D3D11_ALLOCATOR_UNLOCK (self);
   }
@@ -650,6 +655,7 @@ gst_d3d11_allocator_init (GstD3D11Allocator * allocator)
   priv = gst_d3d11_allocator_get_instance_private (allocator);
   g_mutex_init (&priv->lock);
   g_cond_init (&priv->cond);
+  priv->array_texture_size = 1;
 
   allocator->priv = priv;
 }
@@ -964,6 +970,8 @@ gst_d3d11_allocator_alloc (GstD3D11Allocator * allocator,
           TRUE, sizeof (guint8), desc->ArraySize);
       g_array_set_size (priv->array_in_use, desc->ArraySize);
 
+      priv->array_texture_size = desc->ArraySize;
+
       if ((desc->BindFlags & D3D11_BIND_DECODER) == D3D11_BIND_DECODER &&
           !priv->decoder_output_view_array) {
         priv->decoder_output_view_array = g_array_sized_new (FALSE,
@@ -997,6 +1005,7 @@ gst_d3d11_allocator_alloc (GstD3D11Allocator * allocator,
     }
 
     g_array_index (priv->array_in_use, guint8, index_to_use) = 1;
+    priv->num_array_textures_in_use++;
 
     GST_D3D11_ALLOCATOR_UNLOCK (allocator);
 
@@ -1133,6 +1142,45 @@ gst_d3d11_allocator_set_flushing (GstD3D11Allocator * allocator,
   GST_D3D11_ALLOCATOR_UNLOCK (allocator);
 }
 
+/**
+ * gst_d3d11_allocator_get_texture_array_size:
+ * @allocator: a #GstD3D11Allocator
+ * @array_size: (out) (optional): the size of texture array
+ * @num_texture_in_use: (out) (optional): the number of textures in use
+ *
+ * Returns: %TRUE if the size of texture array is known
+ *
+ * Since: 1.20
+ */
+gboolean
+gst_d3d11_allocator_get_texture_array_size (GstD3D11Allocator * allocator,
+    guint * array_size, guint * num_texture_in_use)
+{
+  GstD3D11AllocatorPrivate *priv;
+
+  g_return_val_if_fail (GST_IS_D3D11_ALLOCATOR (allocator), FALSE);
+
+  priv = allocator->priv;
+
+  /* For non-array-texture memory, the size is 1 */
+  if (array_size)
+    *array_size = 1;
+  if (num_texture_in_use)
+    *num_texture_in_use = priv->array_texture_size;
+
+  /* size == 1 means we are not texture pool allocator */
+  if (priv->array_texture_size == 1)
+    return TRUE;
+
+  if (num_texture_in_use) {
+    GST_D3D11_ALLOCATOR_LOCK (allocator);
+    *num_texture_in_use = priv->array_texture_size;
+    GST_D3D11_ALLOCATOR_UNLOCK (allocator);
+  }
+
+  return TRUE;
+}
+
 /**
  * gst_is_d3d11_memory:
  * @mem: a #GstMemory

gst-libs/gst/d3d11/gstd3d11memory.h

@@ -168,6 +168,11 @@ GstMemory *         gst_d3d11_allocator_alloc_staging (GstD3D11Allocator * alloc
                                                        GstD3D11AllocationFlags flags,
                                                        gint * stride);
 
+GST_D3D11_API
+gboolean            gst_d3d11_allocator_get_texture_array_size (GstD3D11Allocator * allocator,
+                                                                guint * array_size,
+                                                                guint * num_texture_in_use);
+
 GST_D3D11_API
 void                gst_d3d11_allocator_set_flushing (GstD3D11Allocator * allocator,
                                                       gboolean flushing);