diff --git a/src/libsysprof-analyze/sysprof-document-frame-private.h b/src/libsysprof-analyze/sysprof-document-frame-private.h
index c3d43834..9e0ea4c5 100644
--- a/src/libsysprof-analyze/sysprof-document-frame-private.h
+++ b/src/libsysprof-analyze/sysprof-document-frame-private.h
@@ -31,8 +31,8 @@ struct _SysprofDocumentFrameClass
   GObjectClass parent_class;
 };
 
-SysprofDocumentFrame *sysprof_document_frame_new (GMappedFile   *mapped,
-                                                  gconstpointer  data,
-                                                  gboolean       is_native);
+SysprofDocumentFrame *_sysprof_document_frame_new (GMappedFile               *mapped,
+                                                   const SysprofCaptureFrame *frame,
+                                                   gboolean                   needs_swap);
 
 G_END_DECLS
diff --git a/src/libsysprof-analyze/sysprof-document-frame.c b/src/libsysprof-analyze/sysprof-document-frame.c
index 6b539b60..e3e8bad5 100644
--- a/src/libsysprof-analyze/sysprof-document-frame.c
+++ b/src/libsysprof-analyze/sysprof-document-frame.c
@@ -26,7 +26,7 @@ typedef struct _SysprofDocumentFramePrivate
 {
   GMappedFile *mapped_file;
   const SysprofCaptureFrame *frame;
-  guint is_native : 1;
+  guint needs_swap : 1;
 } SysprofDocumentFramePrivate;
 
 G_DEFINE_TYPE_WITH_PRIVATE (SysprofDocumentFrame, sysprof_document_frame, G_TYPE_OBJECT)
@@ -50,7 +50,7 @@ sysprof_document_frame_finalize (GObject *object)
   g_clear_pointer (&priv->mapped_file, g_mapped_file_unref);
 
   priv->frame = NULL;
-  priv->is_native = 0;
+  priv->needs_swap = 0;
 
   G_OBJECT_CLASS (sysprof_document_frame_parent_class)->finalize (object);
 }
@@ -120,9 +120,9 @@ sysprof_document_frame_init (SysprofDocumentFrame *self)
 }
 
 SysprofDocumentFrame *
-sysprof_document_frame_new (GMappedFile   *mapped_file,
-                            gconstpointer  data,
-                            gboolean       is_native)
+_sysprof_document_frame_new (GMappedFile               *mapped_file,
+                             const SysprofCaptureFrame *frame,
+                             gboolean                   needs_swap)
 {
   SysprofDocumentFrame *self;
   SysprofDocumentFramePrivate *priv;
@@ -131,8 +131,8 @@ sysprof_document_frame_new (GMappedFile   *mapped_file,
 
   priv = sysprof_document_frame_get_instance_private (self);
   priv->mapped_file = g_mapped_file_ref (mapped_file);
-  priv->frame = data;
-  priv->is_native = !!is_native;
+  priv->frame = frame;
+  priv->needs_swap = !!needs_swap;
 
   return self;
 }
@@ -145,7 +145,7 @@ sysprof_document_frame_get_cpu (SysprofDocumentFrame *self)
 
   g_return_val_if_fail (SYSPROF_IS_DOCUMENT_FRAME (self), 0);
 
-  if G_LIKELY (priv->is_native)
+  if G_LIKELY (priv->needs_swap)
     ret = priv->frame->cpu;
   else
     ret = GUINT32_SWAP_LE_BE (priv->frame->cpu);
@@ -161,7 +161,7 @@ sysprof_document_frame_get_pid (SysprofDocumentFrame *self)
 
   g_return_val_if_fail (SYSPROF_IS_DOCUMENT_FRAME (self), 0);
 
-  if G_LIKELY (priv->is_native)
+  if G_LIKELY (priv->needs_swap)
     ret = priv->frame->pid;
   else
     ret = GUINT32_SWAP_LE_BE (priv->frame->pid);
@@ -177,7 +177,7 @@ sysprof_document_frame_get_time (SysprofDocumentFrame *self)
 
   g_return_val_if_fail (SYSPROF_IS_DOCUMENT_FRAME (self), 0);
 
-  if G_LIKELY (priv->is_native)
+  if G_LIKELY (priv->needs_swap)
     ret = priv->frame->time;
   else
     ret = GUINT32_SWAP_LE_BE (priv->frame->time);
diff --git a/src/libsysprof-analyze/sysprof-document.c b/src/libsysprof-analyze/sysprof-document.c
index 588d9b75..43d5d468 100644
--- a/src/libsysprof-analyze/sysprof-document.c
+++ b/src/libsysprof-analyze/sysprof-document.c
@@ -33,7 +33,7 @@ struct _SysprofDocument
   GPtrArray                *frames;
   GMappedFile              *mapped_file;
   SysprofCaptureFileHeader  header;
-  guint                     is_native : 1;
+  guint                     needs_swap : 1;
 };
 
 static GType
@@ -57,9 +57,9 @@ sysprof_document_get_item (GListModel *model,
   if (position >= self->frames->len)
     return NULL;
 
-  return sysprof_document_frame_new (self->mapped_file,
-                                     g_ptr_array_index (self->frames, position),
-                                     self->is_native);
+  return _sysprof_document_frame_new (self->mapped_file,
+                                      g_ptr_array_index (self->frames, position),
+                                      self->needs_swap);
 }
 
 static void
@@ -121,12 +121,12 @@ sysprof_document_load (SysprofDocument  *self,
   /* Keep a copy of our header */
   memcpy (&self->header, data, sizeof self->header);
 #if G_BYTE_ORDER == G_LITTLE_ENDIAN
-  self->is_native = !!self->header.little_endian;
+  self->needs_swap = !self->header.little_endian;
 #else
-  self->is_native = !self->header.little_endian;
+  self->needs_swap = !!self->header.little_endian;
 #endif
 
-  if (!self->is_native)
+  if (self->needs_swap)
     {
       self->header.time = GUINT64_SWAP_LE_BE (self->header.time);
       self->header.end_time = GUINT64_SWAP_LE_BE (self->header.end_time);
@@ -138,8 +138,8 @@ sysprof_document_load (SysprofDocument  *self,
       guint16 frame_len;
 
       memcpy (&frame_len, &data[pos], sizeof frame_len);
-      if (!self->is_native)
-        frame_len = GUINT16_SWAP_LE_BE (self->is_native);
+      if (self->needs_swap)
+        frame_len = GUINT16_SWAP_LE_BE (frame_len);
 
       if (frame_len < sizeof (SysprofCaptureFrame))
         break;