From d11b219d40d7c72156fd11c335fde27212997957 Mon Sep 17 00:00:00 2001
From: Richard Antalik <richardantalik@gmail.com>
Date: Thu, 17 Dec 2020 02:11:22 +0100
Subject: Fix T83869: Crash when creating Sequencer in new scene

Crash on null dereference in `SEQ_timeline_boundbox()`. This function was
generalized in rB9e4a4c2e996c to work on arbitrary `seqbase`.

Fixed by refactoring `SEQ_timeline_boundbox()` functions to return default
sane values if `seqbase` is `NULL`

Reviewed By: HooglyBoogly

Differential Revision: https://developer.blender.org/D9878
---
 source/blender/sequencer/SEQ_sequencer.h     |  1 +
 source/blender/sequencer/intern/sequencer.c  | 14 +++++++++++++
 source/blender/sequencer/intern/strip_time.c | 30 +++++++++++++---------------
 3 files changed, 29 insertions(+), 16 deletions(-)

(limited to 'source/blender/sequencer')

diff --git a/source/blender/sequencer/SEQ_sequencer.h b/source/blender/sequencer/SEQ_sequencer.h
index 9b4c88520b4..3a9c23de5cc 100644
--- a/source/blender/sequencer/SEQ_sequencer.h
+++ b/source/blender/sequencer/SEQ_sequencer.h
@@ -194,6 +194,7 @@ struct SequencerToolSettings *SEQ_tool_settings_copy(struct SequencerToolSetting
 struct Editing *BKE_sequencer_editing_get(struct Scene *scene, bool alloc);
 struct Editing *BKE_sequencer_editing_ensure(struct Scene *scene);
 void BKE_sequencer_editing_free(struct Scene *scene, const bool do_id_user);
+struct ListBase *SEQ_active_seqbase_get(const struct Editing *ed);
 void BKE_sequencer_sort(struct Scene *scene);
 struct Sequence *BKE_sequencer_from_elem(ListBase *seqbase, struct StripElem *se);
 struct Sequence *BKE_sequencer_active_get(struct Scene *scene);
diff --git a/source/blender/sequencer/intern/sequencer.c b/source/blender/sequencer/intern/sequencer.c
index 82971a30c31..87b608ef141 100644
--- a/source/blender/sequencer/intern/sequencer.c
+++ b/source/blender/sequencer/intern/sequencer.c
@@ -327,6 +327,20 @@ void SEQ_tool_settings_fit_method_set(Scene *scene, eSeqImageFitMethod fit_metho
   tool_settings->fit_method = fit_method;
 }
 
+/**
+ * Get seqbase that is being viewed currently. This can be main seqbase or meta strip seqbase
+ *
+ * \param ed: sequence editor data
+ * \return pointer to active seqbase. returns NULL if ed is NULL
+ */
+ListBase *SEQ_active_seqbase_get(const Editing *ed)
+{
+  if (ed == NULL) {
+    return NULL;
+  }
+
+  return ed->seqbasep;
+}
 /** \} */
 
 /* -------------------------------------------------------------------- */
diff --git a/source/blender/sequencer/intern/strip_time.c b/source/blender/sequencer/intern/strip_time.c
index 015d81cc217..d9074b2a683 100644
--- a/source/blender/sequencer/intern/strip_time.c
+++ b/source/blender/sequencer/intern/strip_time.c
@@ -361,28 +361,26 @@ float BKE_sequence_get_fps(Scene *scene, Sequence *seq)
  */
 void SEQ_timeline_boundbox(const Scene *scene, const ListBase *seqbase, rctf *rect)
 {
-  float min[2], max[2];
-  min[0] = scene->r.sfra;
-  max[0] = scene->r.efra + 1;
-  min[1] = 0.0;
-  max[1] = 8.0;
+  rect->xmin = scene->r.sfra;
+  rect->xmax = scene->r.efra + 1;
+  rect->ymin = 0.0f;
+  rect->ymax = 8.0f;
+
+  if (seqbase == NULL) {
+    return;
+  }
 
   LISTBASE_FOREACH (Sequence *, seq, seqbase) {
-    if (min[0] > seq->startdisp - 1) {
-      min[0] = seq->startdisp - 1;
+    if (rect->xmin > seq->startdisp - 1) {
+      rect->xmin = seq->startdisp - 1;
     }
-    if (max[0] < seq->enddisp + 1) {
-      max[0] = seq->enddisp + 1;
+    if (rect->xmax < seq->enddisp + 1) {
+      rect->xmax = seq->enddisp + 1;
     }
-    if (max[1] < seq->machine + 2) {
-      max[1] = seq->machine + 2;
+    if (rect->ymax < seq->machine + 2) {
+      rect->ymax = seq->machine + 2;
     }
   }
-
-  rect->xmin = min[0];
-  rect->xmax = max[0];
-  rect->ymin = min[1];
-  rect->ymax = max[1];
 }
 
 /**
-- 
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