Added locking for history and style operations

As develop history_mutex and global db_image mutexes are both of recursive type we
can and should use them for locking the history or image struct while modifying history.

src/common/styles.c

@@ -664,6 +664,7 @@ void dt_styles_apply_style_item(dt_develop_t *dev,
                                 const gboolean append)
 {
   // get any instance of the same operation so we can copy it
+  dt_pthread_mutex_lock(&dev->history_mutex);
   dt_iop_module_t *mod_src =
     dt_iop_get_module_by_op_priority(dev->iop, style_item->operation, -1);
 
@@ -797,6 +798,7 @@ void dt_styles_apply_style_item(dt_develop_t *dev,
       free(module);
     }
   }
+  dt_pthread_mutex_unlock(&dev->history_mutex);
 }
 
 void _styles_apply_to_image_ext(const char *name,
@@ -997,27 +999,32 @@ void dt_styles_apply_to_image(const char *name,
                               const gboolean overwrite,
                               const dt_imgid_t imgid)
 {
+  dt_lock_image(imgid);
   _styles_apply_to_image_ext(name, duplicate, overwrite, imgid, TRUE);
+  dt_unlock_image(imgid);
 }
 
 void dt_styles_apply_to_dev(const char *name, const dt_imgid_t imgid)
 {
-  if(!darktable.develop || !dt_is_valid_imgid(darktable.develop->image_storage.id))
+  dt_develop_t *dev = darktable.develop;
+  if(!dev || !dt_is_valid_imgid(dev->image_storage.id))
     return;
 
+  dt_pthread_mutex_lock(&dev->history_mutex);
   /* write current history changes so nothing gets lost */
-  dt_dev_write_history(darktable.develop);
+  dt_dev_write_history(dev);
 
-  dt_dev_undo_start_record(darktable.develop);
+  dt_dev_undo_start_record(dev);
 
   /* apply style on image and reload*/
   _styles_apply_to_image_ext(name, FALSE, FALSE, imgid, FALSE);
-  dt_dev_reload_image(darktable.develop, imgid);
-
-  DT_CONTROL_SIGNAL_RAISE(DT_SIGNAL_TAG_CHANGED);
+  dt_dev_reload_image(dev, imgid);
 
   /* record current history state : after change (needed for undo) */
-  dt_dev_undo_end_record(darktable.develop);
+  dt_dev_undo_end_record(dev);
+  dt_pthread_mutex_unlock(&dev->history_mutex);
+
+  DT_CONTROL_SIGNAL_RAISE(DT_SIGNAL_TAG_CHANGED);
 
   // rebuild the accelerators (style might have changed order)
   dt_iop_connect_accels_all();

src/develop/develop.c

@@ -621,9 +621,11 @@ void dt_dev_load_image(dt_develop_t *dev,
   // we need a global lock as the dev->iop set must not be changed
   // until read history is terminated
   dt_pthread_mutex_lock(&darktable.dev_threadsafe);
+  dt_pthread_mutex_lock(&dev->history_mutex);
   dev->iop = dt_iop_load_modules(dev);
 
   dt_dev_read_history_ext(dev, dev->image_storage.id, FALSE);
+  dt_pthread_mutex_unlock(&dev->history_mutex);
   dt_pthread_mutex_unlock(&darktable.dev_threadsafe);
 
   dev->first_load = FALSE;
@@ -797,6 +799,7 @@ static void _dev_add_history_item_ext(dt_develop_t *dev,
                                       const gboolean auto_name_module)
 {
   // try to auto-name the module based on the presets if possible
+  dt_pthread_mutex_lock(&dev->history_mutex);
   if(auto_name_module)
   {
     _dev_auto_module_label(dev, module);
@@ -938,6 +941,7 @@ static void _dev_add_history_item_ext(dt_develop_t *dev,
   // possibly save database and sidecar file
   if(dev->autosaving)
     _dev_auto_save(dev);
+  dt_pthread_mutex_unlock(&dev->history_mutex);
 }
 
 const dt_dev_history_item_t *dt_dev_get_history_item(dt_develop_t *dev, const char *op)
@@ -1072,6 +1076,7 @@ void dt_dev_add_masks_history_item_ext(dt_develop_t *dev,
 {
   dt_iop_module_t *module = _module;
   gboolean enable = _enable;
+  dt_pthread_mutex_lock(&dev->history_mutex);
 
   // no module means that is called from the mask manager, so find the iop
   if(module == NULL)
@@ -1094,6 +1099,7 @@ void dt_dev_add_masks_history_item_ext(dt_develop_t *dev,
   else
     dt_print(DT_DEBUG_ALWAYS,
              "[dt_dev_add_masks_history_item_ext] can't find mask manager module");
+  dt_pthread_mutex_unlock(&dev->history_mutex);
 }
 
 void dt_dev_add_masks_history_item(
@@ -1156,6 +1162,7 @@ void dt_dev_reload_history_items(dt_develop_t *dev)
   dev->focus_hash = 0;
 
   dt_lock_image(dev->image_storage.id);
+  dt_pthread_mutex_lock(&dev->history_mutex);
 
   dt_ioppr_set_default_iop_order(dev, dev->image_storage.id);
   dt_dev_pop_history_items(dev, 0);
@@ -1211,11 +1218,13 @@ void dt_dev_reload_history_items(dt_develop_t *dev)
   // set the module list order
   dt_dev_reorder_gui_module_list(dev);
 
+  dt_pthread_mutex_unlock(&dev->history_mutex);
   dt_unlock_image(dev->image_storage.id);
 }
 
 void dt_dev_pop_history_items_ext(dt_develop_t *dev, const int32_t cnt)
 {
+  dt_pthread_mutex_lock(&dev->history_mutex);
   dt_ioppr_check_iop_order(dev, 0, "dt_dev_pop_history_items_ext begin");
 
   const int end_prev = dev->history_end;
@@ -1287,6 +1296,7 @@ void dt_dev_pop_history_items_ext(dt_develop_t *dev, const int32_t cnt)
   }
   if(masks_changed)
     dt_masks_replace_current_forms(dev, forms);
+  dt_pthread_mutex_unlock(&dev->history_mutex);
 }
 
 void dt_dev_pop_history_items(dt_develop_t *dev, const int32_t cnt)