Expose background job info to Python

Add `bpy.app.is_job_running(job_type)` as high-level indicator. Job
types currently exposed are `WM_JOB_TYPE_RENDER`,
`WM_JOB_TYPE_RENDER_PREVIEW`, and `WM_JOB_TYPE_OBJECT_BAKE`, as strings
with the `WM_JOB_TYPE_` prefix removed. The functions can be polled by
Python code to determine whether such background work is still ongoing
or not.

Furthermore, new app handles are added for
`object_bake_{pre,complete,canceled}`, which are called respectively
before an object baking job starts, completes sucessfully, and stops due
to a cancellation.

Motivation: There are various cases where Python can trigger the
execution of a background job, without getting notification that that
background job is done. As a result, it's hard to do things like
cleanups, or auto-quitting Blender after the work is done.

The approach in this commit can easily be extended with other job types,
when the need arises. The rendering of asset previews is one that's
likely to be added sooner than later, as there have already been
requests about this.

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D14587

1 files changed, 9 insertions, 0 deletions

diff --git a/source/blender/windowmanager/WM_api.h b/source/blender/windowmanager/WM_api.h
index 890872a06bc..dec1260ad1d 100644
--- a/source/blender/windowmanager/WM_api.h
+++ b/source/blender/windowmanager/WM_api.h
@@ -1400,6 +1400,14 @@ void WM_jobs_callbacks(struct wmJob *,
                        void (*update)(void *),
                        void (*endjob)(void *));
 
+void WM_jobs_callbacks_ex(wmJob *wm_job,
+                          wm_jobs_start_callback startjob,
+                          void (*initjob)(void *),
+                          void (*update)(void *),
+                          void (*endjob)(void *),
+                          void (*completed)(void *),
+                          void (*canceled)(void *));
+
 /**
  * If job running, the same owner gave it a new job.
  * if different owner starts existing startjob, it suspends itself
@@ -1426,6 +1434,7 @@ void WM_jobs_kill_all_except(struct wmWindowManager *wm, const void *owner);
 void WM_jobs_kill_type(struct wmWindowManager *wm, const void *owner, int job_type);
 
 bool WM_jobs_has_running(const struct wmWindowManager *wm);
+bool WM_jobs_has_running_type(const struct wmWindowManager *wm, int job_type);
 
 void WM_job_main_thread_lock_acquire(struct wmJob *job);
 void WM_job_main_thread_lock_release(struct wmJob *job);