d3d11: Don't use g_alloca()

_alloca CRT function is deprecated. Moreover, stack allocation
for string is not a good idea. We can use _malloca inline
function instead, but all use of _alloca in d3d11 library/plugin
are not performance critical path at all.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3652>

subprojects/gst-plugins-bad/gst-libs/gst/d3d11/gstd3d11device.cpp

@@ -225,7 +225,7 @@ gst_d3d11_device_d3d11_debug (GstD3D11Device * device,
       return;
     }
 
-    msg = (D3D11_MESSAGE *) g_alloca (msg_len);
+    msg = (D3D11_MESSAGE *) g_malloc0 (msg_len);
     hr = info_queue->GetMessage (i, msg, &msg_len);
 
     level = d3d11_message_severity_to_gst (msg->Severity);
@@ -238,6 +238,7 @@ gst_d3d11_device_d3d11_debug (GstD3D11Device * device,
 
     gst_debug_log (gst_d3d11_debug_layer_debug, level, file, function, line,
         G_OBJECT (device), "D3D11InfoQueue: %s", msg->pDescription);
+    g_free (msg);
   }
 
   info_queue->ClearStoredMessages ();
@@ -336,12 +337,13 @@ gst_d3d11_device_dxgi_debug (GstD3D11Device * device,
       return;
     }
 
-    msg = (DXGI_INFO_QUEUE_MESSAGE *) g_alloca (msg_len);
+    msg = (DXGI_INFO_QUEUE_MESSAGE *) g_malloc0 (msg_len);
     hr = info_queue->GetMessage (DXGI_DEBUG_ALL, i, msg, &msg_len);
 
     level = dxgi_info_queue_message_severity_to_gst (msg->Severity);
     gst_debug_log (gst_d3d11_debug_layer_debug, level, file, function, line,
         G_OBJECT (device), "DXGIInfoQueue: %s", msg->pDescription);
+    g_free (msg);
   }
 
   info_queue->ClearStoredMessages (DXGI_DEBUG_ALL);

subprojects/gst-plugins-bad/sys/d3d11/gstd3d11decoder.cpp

@@ -644,6 +644,7 @@ gst_d3d11_decoder_get_supported_decoder_profile (GstD3D11Device * device,
   ID3D11VideoDevice *video_device;
   const GUID **profile_list = nullptr;
   guint profile_size = 0;
+  gboolean ret = FALSE;
 
   g_return_val_if_fail (GST_IS_D3D11_DEVICE (device), FALSE);
   g_return_val_if_fail (selected_profile != nullptr, FALSE);
@@ -713,13 +714,13 @@ gst_d3d11_decoder_get_supported_decoder_profile (GstD3D11Device * device,
 
   GST_DEBUG_OBJECT (device,
       "Have %u available decoder profiles", available_profile_count);
-  guid_list = (GUID *) g_alloca (sizeof (GUID) * available_profile_count);
+  guid_list = g_new0 (GUID, available_profile_count);
 
   for (i = 0; i < available_profile_count; i++) {
     hr = video_device->GetVideoDecoderProfile (i, &guid_list[i]);
     if (!gst_d3d11_result (hr, device)) {
       GST_WARNING_OBJECT (device, "Failed to get %d th decoder profile", i);
-      return FALSE;
+      goto out;
     }
   }
 
@@ -759,7 +760,7 @@ gst_d3d11_decoder_get_supported_decoder_profile (GstD3D11Device * device,
   if (!profile) {
     GST_INFO_OBJECT (device, "No supported decoder profile for %s codec",
         gst_dxva_codec_to_string (codec));
-    return FALSE;
+    goto out;
   }
 
   *selected_profile = profile;
@@ -772,7 +773,11 @@ gst_d3d11_decoder_get_supported_decoder_profile (GstD3D11Device * device,
       profile->Data4[3], profile->Data4[4], profile->Data4[5],
       profile->Data4[6], profile->Data4[7]);
 
-  return TRUE;
+  ret = TRUE;
+
+out:
+  g_free (guid_list);
+  return ret;
 }
 
 gboolean
@@ -894,7 +899,7 @@ gst_d3d11_decoder_open (GstD3D11Decoder * self)
   HRESULT hr;
   BOOL can_support = FALSE;
   guint config_count;
-  D3D11_VIDEO_DECODER_CONFIG *config_list;
+  D3D11_VIDEO_DECODER_CONFIG *config_list = NULL;
   D3D11_VIDEO_DECODER_CONFIG *best_config = NULL;
   D3D11_VIDEO_DECODER_DESC decoder_desc = { 0, };
   const GUID *selected_profile = NULL;
@@ -995,9 +1000,7 @@ gst_d3d11_decoder_open (GstD3D11Decoder * self)
 
   GST_DEBUG_OBJECT (self, "Total %d config available", config_count);
 
-  config_list = (D3D11_VIDEO_DECODER_CONFIG *)
+  config_list = g_new0 (D3D11_VIDEO_DECODER_CONFIG, config_count);
-      g_alloca (sizeof (D3D11_VIDEO_DECODER_CONFIG) * config_count);
-
   for (i = 0; i < config_count; i++) {
     hr = video_device->GetVideoDecoderConfig (&decoder_desc, i,
         &config_list[i]);
@@ -1074,10 +1077,12 @@ gst_d3d11_decoder_open (GstD3D11Decoder * self)
   self->opened = TRUE;
 
   gst_d3d11_decoder_enable_high_precision_timer (self);
+  g_free (config_list);
 
   return TRUE;
 
 error:
+  g_free (config_list);
   gst_d3d11_decoder_reset (self);
 
   return FALSE;

subprojects/gst-plugins-bad/sys/d3d11/gstd3d11screencapturedevice.cpp

@@ -175,6 +175,9 @@ get_monitor_name (const MONITORINFOEXW * info,
   UINT32 num_path = 0;
   UINT32 num_mode = 0;
   LONG query_ret;
+  DISPLAYCONFIG_PATH_INFO *path_infos = nullptr;
+  DISPLAYCONFIG_MODE_INFO *mode_infos = nullptr;
+  gboolean ret = FALSE;
 
   memset (target, 0, sizeof (DISPLAYCONFIG_TARGET_DEVICE_NAME));
 
@@ -183,15 +186,13 @@ get_monitor_name (const MONITORINFOEXW * info,
   if (query_ret != ERROR_SUCCESS || num_path == 0 || num_mode == 0)
     return FALSE;
 
-  DISPLAYCONFIG_PATH_INFO *path_infos = (DISPLAYCONFIG_PATH_INFO *)
+  path_infos = g_new0 (DISPLAYCONFIG_PATH_INFO, num_path);
-      g_alloca (num_path * sizeof (DISPLAYCONFIG_PATH_INFO));
+  mode_infos = g_new0 (DISPLAYCONFIG_MODE_INFO, num_mode);
-  DISPLAYCONFIG_MODE_INFO *mode_infos = (DISPLAYCONFIG_MODE_INFO *)
-      g_alloca (num_mode * sizeof (DISPLAYCONFIG_MODE_INFO));
 
   query_ret = QueryDisplayConfig (QDC_ONLY_ACTIVE_PATHS, &num_path,
       path_infos, &num_mode, mode_infos, nullptr);
   if (query_ret != ERROR_SUCCESS)
-    return FALSE;
+    goto out;
 
   for (UINT32 i = 0; i < num_path; i++) {
     DISPLAYCONFIG_PATH_INFO *p = &path_infos[i];
@@ -226,10 +227,15 @@ get_monitor_name (const MONITORINFOEXW * info,
 
     memcpy (target, &tmp, sizeof (DISPLAYCONFIG_TARGET_DEVICE_NAME));
 
-    return TRUE;
+    ret = TRUE;
+    break;
   }
 
-  return FALSE;
+out:
+  g_free (path_infos);
+  g_free (mode_infos);
+
+  return ret;
 }
 
 /* XXX: please bump MinGW toolchain version,