Make main library safe(er) for the threaded usage

Added a lock to the Main which is getting acquired and released
when modifying it's lists.

Should not be any functional changes now, it just means Main is
now considered safe without worrying about locks in the callee.

6 files changed, 19 insertions, 8 deletions

diff --git a/source/blender/blenkernel/BKE_library.h b/source/blender/blenkernel/BKE_library.h
index 55c71ff49cf..c78ea21b9dd 100644
--- a/source/blender/blenkernel/BKE_library.h
+++ b/source/blender/blenkernel/BKE_library.h
@@ -77,7 +77,7 @@ int set_listbasepointers(struct Main *main, struct ListBase **lb);
 void BKE_libblock_free(struct Main *bmain, void *idv);
 void BKE_libblock_free_ex(struct Main *bmain, void *idv, bool do_id_user);
 void BKE_libblock_free_us(struct Main *bmain, void *idv);
-void BKE_libblock_free_data(struct ID *id);
+void BKE_libblock_free_data(struct Main *bmain, struct ID *id);
 
 
 /* Main API */
diff --git a/source/blender/blenkernel/BKE_main.h b/source/blender/blenkernel/BKE_main.h
index 721866daff5..ade5733fa4f 100644
--- a/source/blender/blenkernel/BKE_main.h
+++ b/source/blender/blenkernel/BKE_main.h
@@ -41,6 +41,7 @@
  *
  */
 #include "DNA_listBase.h"
+#include "BLI_threads.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -96,6 +97,8 @@ typedef struct Main {
 
 	/* Evaluation context used by viewport */
 	struct EvaluationContext *eval_ctx;
+
+	SpinLock lock;
 } Main;
 
 #define MAIN_VERSION_ATLEAST(main, ver, subver) \
diff --git a/source/blender/blenkernel/intern/library.c b/source/blender/blenkernel/intern/library.c
index fe2d1481581..9a74edb03c9 100644
--- a/source/blender/blenkernel/intern/library.c
+++ b/source/blender/blenkernel/intern/library.c
@@ -747,12 +747,14 @@ void *BKE_libblock_alloc(Main *bmain, short type, const char *name)
 	
 	id = alloc_libblock_notest(type);
 	if (id) {
+		BLI_spin_lock(&bmain->lock);
 		BLI_addtail(lb, id);
 		id->us = 1;
 		id->icon_id = 0;
 		*( (short *)id->name) = type;
 		new_id(lb, id, name);
 		/* alphabetic insertion: is in new_id */
+		BLI_spin_unlock(&bmain->lock);
 	}
 	DAG_id_type_tag(bmain, type);
 	return id;
@@ -881,10 +883,8 @@ static void animdata_dtar_clear_cb(ID *UNUSED(id), AnimData *adt, void *userdata
 	}
 }
 
-void BKE_libblock_free_data(ID *id)
+void BKE_libblock_free_data(Main *bmain, ID *id)
 {
-	Main *bmain = G.main;  /* should eventually be an arg */
-	
 	if (id->properties) {
 		IDP_FreeProperty(id->properties);
 		MEM_freeN(id->properties);
@@ -1008,12 +1008,15 @@ void BKE_libblock_free_ex(Main *bmain, void *idv, bool do_id_user)
 	}
 
 	/* avoid notifying on removed data */
+	BLI_spin_lock(&bmain->lock);
+
 	if (free_notifier_reference_cb)
 		free_notifier_reference_cb(id);
 
 	BLI_remlink(lb, id);
 
-	BKE_libblock_free_data(id);
+	BKE_libblock_free_data(bmain, id);
+	BLI_spin_unlock(&bmain->lock);
 
 	MEM_freeN(id);
 }
@@ -1043,7 +1046,9 @@ void BKE_libblock_free_us(Main *bmain, void *idv)      /* test users */
 Main *BKE_main_new(void)
 {
 	Main *bmain = MEM_callocN(sizeof(Main), "new main");
-	bmain->eval_ctx = MEM_callocN(sizeof(EvaluationContext), "EvaluationContext");
+	bmain->eval_ctx = MEM_callocN(sizeof(EvaluationContext),
+	                              "EvaluationContext");
+	BLI_spin_init(&bmain->lock);
 	return bmain;
 }
 
@@ -1106,6 +1111,7 @@ void BKE_main_free(Main *mainvar)
 		}
 	}
 
+	BLI_spin_end(&mainvar->lock);
 	MEM_freeN(mainvar->eval_ctx);
 	MEM_freeN(mainvar);
 }
diff --git a/source/blender/blenkernel/intern/material.c b/source/blender/blenkernel/intern/material.c
index de3aea9267f..4f6f234c6e1 100644
--- a/source/blender/blenkernel/intern/material.c
+++ b/source/blender/blenkernel/intern/material.c
@@ -780,11 +780,13 @@ void test_object_materials(Main *bmain, ID *id)
 		return;
 	}
 
+	BLI_spin_lock(&bmain->lock);
 	for (ob = bmain->object.first; ob; ob = ob->id.next) {
 		if (ob->data == id) {
 			BKE_material_resize_object(ob, *totcol, false);
 		}
 	}
+	BLI_spin_unlock(&bmain->lock);
 }
 
 void assign_material_id(ID *id, Material *ma, short act)
diff --git a/source/blender/blenkernel/intern/mesh.c b/source/blender/blenkernel/intern/mesh.c
index 7197d560bcc..7c6164a8174 100644
--- a/source/blender/blenkernel/intern/mesh.c
+++ b/source/blender/blenkernel/intern/mesh.c
@@ -2148,7 +2148,7 @@ Mesh *BKE_mesh_new_from_object(
 			 * if it didn't the curve did not have any segments or otherwise 
 			 * would have generated an empty mesh */
 			if (tmpobj->type != OB_MESH) {
-				BKE_libblock_free_us(G.main, tmpobj);
+				BKE_libblock_free_us(bmain, tmpobj);
 				return NULL;
 			}
 
diff --git a/source/blender/blenkernel/intern/node.c b/source/blender/blenkernel/intern/node.c
index c8632a40d1a..56a76a54955 100644
--- a/source/blender/blenkernel/intern/node.c
+++ b/source/blender/blenkernel/intern/node.c
@@ -1777,7 +1777,7 @@ void ntreeFreeTree_ex(bNodeTree *ntree, const bool do_id_user)
 		if (tntree == ntree)
 			break;
 	if (tntree == NULL) {
-		BKE_libblock_free_data(&ntree->id);
+		BKE_libblock_free_data(G.main, &ntree->id);
 	}
 }
 /* same as ntreeFreeTree_ex but always manage users */