[gtk/wip/otte/for-master: 2/2] snapshot: Move sanity checks to a better place

[Benjamin Otte <otte src gnome org>]

commit ef455f5c8574ee1e0fc8ba8218ffa0b824e68658
Author: Benjamin Otte <otte redhat com>
Date:   Thu Apr 1 16:37:47 2021 +0200

    snapshot: Move sanity checks to a better place
    
    Fixes cases where the sanity checks would reject valid code, like when
    using GL shaders on a scaled transform.
    
    Fixes #3819

 gtk/gtksnapshot.c | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)
---
diff --git a/gtk/gtksnapshot.c b/gtk/gtksnapshot.c
index 577565d21a..304abbde79 100644
--- a/gtk/gtksnapshot.c
+++ b/gtk/gtksnapshot.c
@@ -1413,7 +1413,8 @@ gtk_snapshot_append_node_internal (GtkSnapshot   *snapshot,
 }
 
 static GskRenderNode *
-gtk_snapshot_pop_internal (GtkSnapshot *snapshot)
+gtk_snapshot_pop_internal (GtkSnapshot *snapshot,
+                           gboolean     is_texture_pop)
 {
   GtkSnapshotState *state;
   GskRenderNode *node;
@@ -1437,6 +1438,17 @@ gtk_snapshot_pop_internal (GtkSnapshot *snapshot)
       g_warning ("Too many gtk_snapshot_save() calls. %u saves remaining.", forgotten_restores);
     }
 
+  if (is_texture_pop && (state->collect_func != gtk_snapshot_collect_gl_shader_texture))
+    {
+      g_critical ("Unexpected call to gtk_snapshot_gl_shader_pop_texture().");
+      return NULL;
+    }
+  else if (!is_texture_pop && (state->collect_func == gtk_snapshot_collect_gl_shader_texture))
+    {
+      g_critical ("Expected a call to gtk_snapshot_gl_shader_pop_texture().");
+      return NULL;
+    }
+
   return gtk_snapshot_pop_one (snapshot);
 }
 
@@ -1460,7 +1472,7 @@ gtk_snapshot_push_collect (GtkSnapshot *snapshot)
 GskRenderNode *
 gtk_snapshot_pop_collect (GtkSnapshot *snapshot)
 {
-  GskRenderNode *result = gtk_snapshot_pop_internal (snapshot);
+  GskRenderNode *result = gtk_snapshot_pop_internal (snapshot, FALSE);
 
   return result;
 }
@@ -1483,7 +1495,7 @@ gtk_snapshot_to_node (GtkSnapshot *snapshot)
 {
   GskRenderNode *result;
 
-  result = gtk_snapshot_pop_internal (snapshot);
+  result = gtk_snapshot_pop_internal (snapshot, FALSE);
 
   /* We should have exactly our initial state */
   if (!gtk_snapshot_states_is_empty (&snapshot->state_stack))
@@ -1551,13 +1563,9 @@ gtk_snapshot_to_paintable (GtkSnapshot           *snapshot,
 void
 gtk_snapshot_pop (GtkSnapshot *snapshot)
 {
-  GtkSnapshotState *state = gtk_snapshot_get_current_state (snapshot);
   GskRenderNode *node;
 
-  if (state->collect_func == gtk_snapshot_collect_gl_shader_texture)
-    g_warning ("Not enough calls to gtk_snapshot_gl_shader_pop_texture().");
-
-  node = gtk_snapshot_pop_internal (snapshot);
+  node = gtk_snapshot_pop_internal (snapshot, FALSE);
 
   if (node)
     gtk_snapshot_append_node_internal (snapshot, node);
@@ -1577,18 +1585,9 @@ gtk_snapshot_pop (GtkSnapshot *snapshot)
 void
 gtk_snapshot_gl_shader_pop_texture (GtkSnapshot *snapshot)
 {
-  GtkSnapshotState *state = gtk_snapshot_get_current_state (snapshot);
   G_GNUC_UNUSED GskRenderNode *node;
 
-  if (state->collect_func != gtk_snapshot_collect_gl_shader_texture)
-    {
-      g_warning ("Too many calls to gtk_snapshot_gl_shader_pop_texture().");
-      return;
-    }
-
-  g_assert (state->collect_func == gtk_snapshot_collect_gl_shader_texture);
-
-  node = gtk_snapshot_pop_internal (snapshot);
+  node = gtk_snapshot_pop_internal (snapshot, TRUE);
   g_assert (node == NULL);
 }