Drivers Editing: Added "Copy/Paste" buttons beside "Add Variable" for copying all variables from one driver to another

This was a feature request from a few years back (IIRC from ZanQdo?) to make it
easier to reuse one set of driver variables across several different drivers.

Dev Notes:
* Finally it's done! All that trouble for two little buttons.
* Grr... cmake... grrr!

7 files changed, 291 insertions, 10 deletions

diff --git a/source/blender/editors/animation/CMakeLists.txt b/source/blender/editors/animation/CMakeLists.txt
index 473b0e6bc5a..1bf1bb2a474 100644
--- a/source/blender/editors/animation/CMakeLists.txt
+++ b/source/blender/editors/animation/CMakeLists.txt
@@ -59,6 +59,10 @@ if(WITH_INTERNATIONAL)
 	add_definitions(-DWITH_INTERNATIONAL)
 endif()
 
+if(WITH_PYTHON)
+	add_definitions(-DWITH_PYTHON)
+endif()
+
 add_definitions(${GL_DEFINITIONS})
 
 blender_add_lib(bf_editor_animation "${SRC}" "${INC}" "${INC_SYS}")
diff --git a/source/blender/editors/animation/drivers.c b/source/blender/editors/animation/drivers.c
index 4ddf37aa3a1..27bed693619 100644
--- a/source/blender/editors/animation/drivers.c
+++ b/source/blender/editors/animation/drivers.c
@@ -600,7 +600,7 @@ bool ANIM_paste_driver(ReportList *reports, ID *id, const char rna_path[], int a
 	
 	/* create Driver F-Curve, but without data which will be copied across... */
 	fcu = verify_driver_fcurve(id, rna_path, array_index, -1);
-
+	
 	if (fcu) {
 		/* copy across the curve data from the buffer curve 
 		 * NOTE: this step needs care to not miss new settings
@@ -625,6 +625,120 @@ bool ANIM_paste_driver(ReportList *reports, ID *id, const char rna_path[], int a
 }
 
 /* ************************************************** */
+/* Driver Management API - Copy/Paste Driver Variables */
+
+/* Copy/Paste Buffer for Driver Variables... */
+static ListBase driver_vars_copybuf = {NULL, NULL};
+
+/* This function frees any MEM_calloc'ed copy/paste buffer data */
+void ANIM_driver_vars_copybuf_free(void)
+{
+	/* Free the driver variables kept in the buffer */
+	if (driver_vars_copybuf.first) {
+		/* We use a dummy driver here, as the variable freeing code assumes there's a driver */
+		ChannelDriver dummy_driver = {{NULL}};
+		dummy_driver.variables = driver_vars_copybuf;
+		
+		/* Free variables (and any data they use) */
+		DriverVar *dvar, *dvarn;
+		for (dvar = driver_vars_copybuf.first; dvar; dvar = dvarn) {
+			dvarn = dvar->next;
+			driver_free_variable(&driver_vars_copybuf, dvar);
+		}
+	}
+	
+	BLI_listbase_clear(&driver_vars_copybuf);
+}
+
+/* Checks if there are driver variables in the copy/paste buffer */
+bool ANIM_driver_vars_can_paste(void)
+{
+	return (BLI_listbase_is_empty(&driver_vars_copybuf) == false);
+}
+
+/* -------------------------------------------------- */
+
+/* Copy the given driver's variables to the buffer */
+bool ANIM_driver_vars_copy(ReportList *reports, FCurve *fcu)
+{
+	/* sanity checks */
+	if (ELEM(NULL, fcu, fcu->driver)) {
+		BKE_report(reports, RPT_ERROR, "No driver to copy variables from");
+		return false;
+	}
+	
+	if (BLI_listbase_is_empty(&fcu->driver->variables)) {
+		BKE_report(reports, RPT_ERROR, "Driver has no variables to copy");
+		return false;
+	}
+	
+	/* clear buffer */
+	ANIM_driver_vars_copybuf_free();
+	
+	/* copy over the variables */
+	driver_variables_copy(&driver_vars_copybuf, &fcu->driver->variables);
+	
+	return (BLI_listbase_is_empty(&driver_vars_copybuf) == false);
+}
+
+/* Paste the variables in the buffer to the given FCurve */
+bool ANIM_driver_vars_paste(ReportList *reports, FCurve *fcu, bool replace)
+{
+	ChannelDriver *driver = (fcu) ? fcu->driver : NULL;
+	ListBase tmp_list = {NULL, NULL};
+	
+	/* sanity checks */
+	if (BLI_listbase_is_empty(&driver_vars_copybuf)) {
+		BKE_report(reports, RPT_ERROR, "No driver variables in clipboard to paste");
+		return false;
+	}
+	
+	if (ELEM(NULL, fcu, fcu->driver)) {
+		BKE_report(reports, RPT_ERROR, "Cannot paste driver variables without a driver");
+		return false;
+	}
+	
+	/* 1) Make a new copy of the variables in the buffer - these will get pasted later... */
+	driver_variables_copy(&tmp_list, &driver_vars_copybuf);
+	
+	/* 2) Prepare destination array */
+	if (replace) {
+		DriverVar *dvar, *dvarn;
+		
+		/* Free all existing vars first - We aren't retaining anything */
+		for (dvar = driver->variables.first; dvar; dvar = dvarn) {
+			dvarn = dvar->next;
+			driver_free_variable_ex(driver, dvar);
+		}
+		
+		BLI_listbase_clear(&driver->variables);
+	}
+	
+	/* 3) Add new vars */
+	if (driver->variables.last) {
+		DriverVar *last = driver->variables.last;
+		DriverVar *first = tmp_list.first;
+		
+		last->next = first;
+		first->prev = last;
+		
+		driver->variables.last = tmp_list.last;
+	}
+	else {
+		driver->variables.first = tmp_list.first;
+		driver->variables.last = tmp_list.last;
+	}
+	
+#ifdef WITH_PYTHON
+	/* since driver variables are cached, the expression needs re-compiling too */
+	if (driver->type == DRIVER_TYPE_PYTHON)
+		driver->flag |= DRIVER_FLAG_RENAMEVAR;
+#endif
+	
+	return true;
+}
+
+/* ************************************************** */
 /* UI-Button Interface */
 
 /* Add Driver - Enum Defines ------------------------- */
diff --git a/source/blender/editors/include/ED_keyframing.h b/source/blender/editors/include/ED_keyframing.h
index 9a411975880..81e2558e765 100644
--- a/source/blender/editors/include/ED_keyframing.h
+++ b/source/blender/editors/include/ED_keyframing.h
@@ -291,6 +291,9 @@ bool ANIM_remove_driver(struct ReportList *reports, struct ID *id, const char rn
 /* Clear copy-paste buffer for drivers */
 void ANIM_drivers_copybuf_free(void);
 
+/* Clear copy-paste buffer for driver variable sets */
+void ANIM_driver_vars_copybuf_free(void);
+
 /* -------- */
 
 /* Returns whether there is a driver in the copy/paste buffer to paste */
@@ -307,6 +310,17 @@ bool ANIM_copy_driver(struct ReportList *reports, struct ID *id, const char rna_
  */
 bool ANIM_paste_driver(struct ReportList *reports, struct ID *id, const char rna_path[], int array_index, short flag);
 
+/* -------- */
+
+/* Checks if there are driver variables in the copy/paste buffer */
+bool ANIM_driver_vars_can_paste(void);
+
+/* Copy the given driver's variables to the buffer */
+bool ANIM_driver_vars_copy(struct ReportList *reports, struct FCurve *fcu);
+
+/* Paste the variables in the buffer to the given FCurve */
+bool ANIM_driver_vars_paste(struct ReportList *reports, struct FCurve *fcu, bool replace);
+
 /* ************ Auto-Keyframing ********************** */
 /* Notes:
  * - All the defines for this (User-Pref settings and Per-Scene settings)
diff --git a/source/blender/editors/space_graph/graph_buttons.c b/source/blender/editors/space_graph/graph_buttons.c
index f8b081eda20..5846a439b3c 100644
--- a/source/blender/editors/space_graph/graph_buttons.c
+++ b/source/blender/editors/space_graph/graph_buttons.c
@@ -516,7 +516,7 @@ static void driver_delete_var_cb(bContext *UNUSED(C), void *driver_v, void *dvar
 	DriverVar *dvar = (DriverVar *)dvar_v;
 	
 	/* remove the active variable */
-	driver_free_variable(driver, dvar);
+	driver_free_variable_ex(driver, dvar);
 }
 
 /* callback to report why a driver variable is invalid */
@@ -825,14 +825,26 @@ static void graph_panel_drivers(const bContext *C, Panel *pa)
 		uiItemL(row, valBuf, ICON_NONE);
 	}
 	
-	/* add driver variables */
-	col = uiLayoutColumn(pa->layout, false);
-	block = uiLayoutGetBlock(col);
-	but = uiDefIconTextBut(block, UI_BTYPE_BUT, B_IPO_DEPCHANGE, ICON_ZOOMIN, IFACE_("Add Variable"),
-	               0, 0, 10 * UI_UNIT_X, UI_UNIT_Y,
-	               NULL, 0.0, 0.0, 0, 0,
-	               TIP_("Driver variables ensure that all dependencies will be accounted for and that drivers will update correctly"));
-	UI_but_func_set(but, driver_add_var_cb, driver, NULL);
+	/* add/copy/paste driver variables */
+	{
+		uiLayout *row;
+		
+		/* add driver variable */
+		row = uiLayoutRow(pa->layout, false);
+		block = uiLayoutGetBlock(row);
+		but = uiDefIconTextBut(block, UI_BTYPE_BUT, B_IPO_DEPCHANGE, ICON_ZOOMIN, IFACE_("Add Variable"),
+	                           0, 0, 10 * UI_UNIT_X, UI_UNIT_Y,
+	                           NULL, 0.0, 0.0, 0, 0,
+	                           TIP_("Driver variables ensure that all dependencies will be accounted for and that drivers will update correctly"));
+		UI_but_func_set(but, driver_add_var_cb, driver, NULL);
+		
+		/* copy/paste (as sub-row) */
+		row = uiLayoutRow(row, true);
+		block = uiLayoutGetBlock(row);
+		
+		uiItemO(row, "", ICON_COPYDOWN, "GRAPH_OT_driver_variables_copy");
+		uiItemO(row, "", ICON_PASTEDOWN, "GRAPH_OT_driver_variables_paste");
+	}
 	
 	/* loop over targets, drawing them */
 	for (dvar = driver->variables.first; dvar; dvar = dvar->next) {
diff --git a/source/blender/editors/space_graph/graph_edit.c b/source/blender/editors/space_graph/graph_edit.c
index dd2ec2401a5..a54b7e141f3 100644
--- a/source/blender/editors/space_graph/graph_edit.c
+++ b/source/blender/editors/space_graph/graph_edit.c
@@ -54,6 +54,7 @@
 
 #include "BLT_translation.h"
 
+#include "BKE_depsgraph.h"
 #include "BKE_fcurve.h"
 #include "BKE_global.h"
 #include "BKE_nla.h"
@@ -2610,3 +2611,130 @@ void GRAPH_OT_fmodifier_paste(wmOperatorType *ot)
 }
 
 /* ************************************************************************** */
+/* Drivers */
+
+/* ******************** Copy Driver Vars Operator *********************** */
+
+static int graph_driver_vars_copy_exec(bContext *C, wmOperator *op)
+{
+	bAnimContext ac;
+	bAnimListElem *ale;
+	bool ok = false;
+	
+	/* get editor data */
+	if (ANIM_animdata_get_context(C, &ac) == 0)
+		return OPERATOR_CANCELLED;
+	
+	/* clear buffer first */
+	ANIM_driver_vars_copybuf_free();
+	
+	/* get the active F-Curve */
+	ale = get_active_fcurve_channel(&ac);
+	
+	/* if this exists, call the copy driver vars API function */
+	if (ale && ale->data) {
+		FCurve *fcu = (FCurve *)ale->data;
+		
+		ok = ANIM_driver_vars_copy(op->reports, fcu);
+		
+		/* free temp data now */
+		MEM_freeN(ale);
+	}
+	
+	/* successful or not? */
+	if (ok == 0)
+		return OPERATOR_CANCELLED;
+	else
+		return OPERATOR_FINISHED;
+}
+ 
+void GRAPH_OT_driver_variables_copy(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name = "Copy Driver Variables";
+	ot->idname = "GRAPH_OT_driver_variables_copy";
+	ot->description = "Copy the driver variables of the active F-Curve";
+	
+	/* api callbacks */
+	ot->exec = graph_driver_vars_copy_exec;
+	ot->poll = graphop_active_fcurve_poll; 
+	
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+}
+
+/* ******************** Paste Driver Vars Operator *********************** */
+
+static int graph_driver_vars_paste_exec(bContext *C, wmOperator *op)
+{
+	bAnimContext ac;
+	
+	ListBase anim_data = {NULL, NULL};
+	bAnimListElem *ale;
+	int filter;
+	
+	const bool replace = RNA_boolean_get(op->ptr, "replace");
+	bool ok = false;
+	
+	/* get editor data */
+	if (ANIM_animdata_get_context(C, &ac) == 0)
+		return OPERATOR_CANCELLED;
+	
+	/* filter data */
+	filter = (ANIMFILTER_DATA_VISIBLE | ANIMFILTER_ACTIVE | ANIMFILTER_FOREDIT | ANIMFILTER_NODUPLIS);
+	ANIM_animdata_filter(&ac, &anim_data, filter, ac.data, ac.datatype);
+	
+	/* paste modifiers */
+	for (ale = anim_data.first; ale; ale = ale->next) {
+		FCurve *fcu = (FCurve *)ale->data;
+		bool paste_ok;
+		
+		printf("pasting vars to %p -> %p\n", fcu, fcu->driver);
+		paste_ok = ANIM_driver_vars_paste(op->reports, fcu, replace);
+		
+		if (paste_ok) {
+			//ale->update |= ANIM_UPDATE_DEPS;
+			printf("now we have: %d vars\n",  BLI_listbase_count(&fcu->driver->variables));
+			ok = true;
+		}
+	}
+	
+	// XXX: something causes a crash after adding the copies (to empty list), if we do an update immediately
+	if (ok) {
+		DAG_relations_tag_update(CTX_data_main(C));
+		//ANIM_animdata_update(&ac, &anim_data);
+	}
+	ANIM_animdata_freelist(&anim_data);
+	
+	/* successful or not? */
+	if (ok) {
+		/* set notifier that keyframes have changed */
+		WM_event_add_notifier(C, NC_SCENE | ND_FRAME, CTX_data_scene(C));
+		return OPERATOR_FINISHED;
+	}
+	else {
+		return OPERATOR_CANCELLED;
+	}
+}
+ 
+void GRAPH_OT_driver_variables_paste(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name = "Paste Driver Variables";
+	ot->idname = "GRAPH_OT_driver_variables_paste";
+	ot->description = "Add copied driver variables to the active driver";
+	
+	/* api callbacks */
+	ot->exec = graph_driver_vars_paste_exec;
+	ot->poll = graphop_active_fcurve_poll;
+	
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+	
+	/* properties */
+	RNA_def_boolean(ot->srna, "only_active", true, "Only Active", "Only paste F-Modifiers on active F-Curve");
+	RNA_def_boolean(ot->srna, "replace", false, "Replace Existing", 
+	                "Replace existing F-Modifiers, instead of just appending to the end of the existing list");
+}
+
+/* ************************************************************************** */
diff --git a/source/blender/editors/space_graph/graph_intern.h b/source/blender/editors/space_graph/graph_intern.h
index a478a86a5e2..b6b711e129f 100644
--- a/source/blender/editors/space_graph/graph_intern.h
+++ b/source/blender/editors/space_graph/graph_intern.h
@@ -148,6 +148,11 @@ void GRAPH_OT_fmodifier_paste(struct wmOperatorType *ot);
 
 /* ----------- */
 
+void GRAPH_OT_driver_variables_copy(struct wmOperatorType *ot);
+void GRAPH_OT_driver_variables_paste(struct wmOperatorType *ot);
+
+/* ----------- */
+
 void GRAPH_OT_ghost_curves_create(struct wmOperatorType *ot);
 void GRAPH_OT_ghost_curves_clear(struct wmOperatorType *ot);
 
diff --git a/source/blender/editors/space_graph/graph_ops.c b/source/blender/editors/space_graph/graph_ops.c
index 59215531ac0..7ffa8250067 100644
--- a/source/blender/editors/space_graph/graph_ops.c
+++ b/source/blender/editors/space_graph/graph_ops.c
@@ -458,6 +458,10 @@ void graphedit_operatortypes(void)
 	WM_operatortype_append(GRAPH_OT_fmodifier_add);
 	WM_operatortype_append(GRAPH_OT_fmodifier_copy);
 	WM_operatortype_append(GRAPH_OT_fmodifier_paste);
+	
+	/* Drivers */
+	WM_operatortype_append(GRAPH_OT_driver_variables_copy);
+	WM_operatortype_append(GRAPH_OT_driver_variables_paste);
 }
 
 void ED_operatormacros_graph(void)