Drag & drop feature:

You now can drop a .blend inside blender window to open it.

Implementation notes:
- Added call to extract icon type for files. Code re-used from
  space_file
- External files that get dropped set icon types too.
  Drop box polls can check for this.
- Also enabled setting op-context for drop operators, this was
  needed to prevent filewindow to open.

source/blender/editors/include/ED_fileselect.h

@@ -93,5 +93,7 @@ void ED_fileselect_clear(struct bContext *C, struct SpaceFile *sfile);
 
 void ED_fileselect_exit(struct bContext *C, struct SpaceFile *sfile);
 
+int ED_file_extension_icon(char *relname);
+
 #endif /* ED_FILES_H */
 

source/blender/editors/screen/screen_ops.c

@@ -64,6 +64,7 @@
 #include "RNA_define.h"
 
 #include "UI_interface.h"
+#include "UI_resources.h"
 
 #include "wm_window.h"
 
@@ -3014,6 +3015,7 @@ void SCENE_OT_delete(wmOperatorType *ot)
 
 /* ****************  Assigning operatortypes to global list, adding handlers **************** */
 
+
 /* called in spacetypes.c */
 void ED_operatortypes_screen(void)
 {
@@ -3087,9 +3089,27 @@ static void keymap_modal_set(wmKeyConfig *keyconf)
 	
 }
 
+static int open_file_drop_poll(bContext *UNUSED(C), wmDrag *drag, wmEvent *UNUSED(event))
+{
+	if(drag->type==WM_DRAG_PATH) {
+		if(drag->icon==ICON_FILE_BLEND)
+		   return 1;
+	}
+	return 0;
+}
+
+static void open_file_drop_copy(wmDrag *drag, wmDropBox *drop)
+{
+	/* copy drag path to properties */
+	RNA_string_set(drop->ptr, "filepath", drag->path);
+	drop->opcontext= WM_OP_EXEC_DEFAULT;
+}
+
+
 /* called in spacetypes.c */
 void ED_keymap_screen(wmKeyConfig *keyconf)
 {
+	ListBase *lb;
 	wmKeyMap *keymap;
 	//wmKeyMapItem *kmi;
 	
@@ -3203,6 +3223,10 @@ void ED_keymap_screen(wmKeyConfig *keyconf)
 	WM_keymap_add_item(keymap, "SCREEN_OT_animation_play", DOWNARROWKEY, KM_PRESS, KM_ALT, 0);
 #endif
 
+	/* dropbox for entire window */
+	lb= WM_dropboxmap_find("Window", 0, 0);
+	WM_dropbox_add(lb, "WM_OT_open_mainfile", open_file_drop_poll, open_file_drop_copy);
+	
 	keymap_modal_set(keyconf);
 }
 

source/blender/editors/space_file/filelist.c

@@ -69,10 +69,11 @@
 
 #include "PIL_time.h"
 
-
 #include "WM_api.h"
 #include "WM_types.h"
 
+#include "UI_resources.h"
+
 #include "filelist.h"
 
 /* max length of library group name within filesel */
@@ -360,7 +361,7 @@ void filelist_filter(FileList* filelist)
 	}
 }
 
-void filelist_init_icons()
+void filelist_init_icons(void)
 {
 	short x, y, k;
 	ImBuf *bbuf;
@@ -383,7 +384,7 @@ void filelist_init_icons()
 	}
 }
 
-void filelist_free_icons()
+void filelist_free_icons(void)
 {
 	int i;
 	for (i=0; i < SPECIAL_IMG_MAX; ++i) {
@@ -720,6 +721,87 @@ void filelist_setfilter_types(struct FileList* filelist, const char *filter_glob
 	BLI_strncpy(filelist->filter_glob, filter_glob, sizeof(filelist->filter_glob));
 }
 
+static int file_extension_type(char *relname)
+{
+	if(BLO_has_bfile_extension(relname)) {
+		return BLENDERFILE;
+	} else if(BLI_testextensie(relname, ".py")) {
+		return PYSCRIPTFILE;
+	} else if(BLI_testextensie(relname, ".txt")
+			  || BLI_testextensie(relname, ".glsl")
+			  || BLI_testextensie(relname, ".data")) {
+		return TEXTFILE;
+	} else if( BLI_testextensie(relname, ".ttf")
+			  || BLI_testextensie(relname, ".ttc")
+			  || BLI_testextensie(relname, ".pfb")
+			  || BLI_testextensie(relname, ".otf")
+			  || BLI_testextensie(relname, ".otc")) {
+		return FTFONTFILE;			
+	} else if(BLI_testextensie(relname, ".btx")) {
+		return BTXFILE;
+	} else if(BLI_testextensie(relname, ".dae")) {
+		return COLLADAFILE;
+	} else if(BLI_testextensie_array(relname, imb_ext_image)
+			  || (G.have_quicktime && BLI_testextensie_array(relname, imb_ext_image_qt))) {
+		return IMAGEFILE;			
+	} else if(BLI_testextensie_array(relname, imb_ext_movie)) {
+		return MOVIEFILE;			
+	} else if(BLI_testextensie_array(relname, imb_ext_audio)) {
+		return SOUNDFILE;
+	} 
+	return 0;
+}
+
+int ED_file_extension_icon(char *relname)
+{
+	int type= file_extension_type(relname);
+	
+	if (type == BLENDERFILE)
+		return ICON_FILE_BLEND;
+	else if (type ==  IMAGEFILE)
+		return ICON_FILE_IMAGE;
+	else if (type ==  MOVIEFILE)
+		return ICON_FILE_MOVIE;
+	else if (type ==  PYSCRIPTFILE)
+		return ICON_FILE_SCRIPT;
+	else if (type ==  PYSCRIPTFILE)
+		return ICON_FILE_SCRIPT;
+	else if (type ==  SOUNDFILE) 
+		return ICON_FILE_SOUND;
+	else if (type ==  FTFONTFILE) 
+		return ICON_FILE_FONT;
+	else if (type ==  BTXFILE) 
+		return ICON_FILE_BLANK;
+	else if (type ==  COLLADAFILE) 
+		return ICON_FILE_BLANK;
+	
+	return ICON_FILE_BLANK;
+}
+
+void filelist_setfiletypes(struct FileList* filelist)
+{
+	struct direntry *file;
+	int num;
+	
+	file= filelist->filelist;
+	
+	for(num=0; num<filelist->numfiles; num++, file++) {
+		file->type= file->s.st_mode;	/* restore the mess below */ 
+		
+		/* Don't check extensions for directories */ 
+		if (file->type & S_IFDIR) {
+			continue;
+		}
+		file->flags = file_extension_type(file->relname);
+		
+		if(filelist->filter_glob
+		   && BLI_testextensie_glob(file->relname, filelist->filter_glob)) {
+			file->flags= OPERATORFILE;
+		}
+		
+	}
+}
+
 static void filelist_read_dir(struct FileList* filelist)
 {
 	char wdir[FILE_MAX];
@@ -734,7 +816,7 @@ static void filelist_read_dir(struct FileList* filelist)
 	filelist->numfiles = BLI_getdir(filelist->dir, &(filelist->filelist));
 
 	if(!chdir(wdir)) {} /* fix warning about not checking return value */
-	filelist_setfiletypes(filelist, G.have_quicktime);
+	filelist_setfiletypes(filelist);
 	filelist_filter(filelist);
 }
 
@@ -790,53 +872,6 @@ void filelist_parent(struct FileList* filelist)
 	filelist_readdir(filelist);
 }
 
-void filelist_setfiletypes(struct FileList* filelist, short has_quicktime)
-{
-	struct direntry *file;
-	int num;
-
-	file= filelist->filelist;
-
-	for(num=0; num<filelist->numfiles; num++, file++) {
-		file->flags= 0;
-		file->type= file->s.st_mode;	/* restore the mess below */ 
-
-			/* Don't check extensions for directories */ 
-		if (file->type & S_IFDIR) {
-			continue;
-		}
-
-		if(BLO_has_bfile_extension(file->relname)) {
-			file->flags |= BLENDERFILE;
-		} else if(BLI_testextensie(file->relname, ".py")) {
-				file->flags |= PYSCRIPTFILE;
-		} else if(BLI_testextensie(file->relname, ".txt")
-					|| BLI_testextensie(file->relname, ".glsl")
-					|| BLI_testextensie(file->relname, ".data")) {
-				file->flags |= TEXTFILE;
-		} else if( BLI_testextensie(file->relname, ".ttf")
-					|| BLI_testextensie(file->relname, ".ttc")
-					|| BLI_testextensie(file->relname, ".pfb")
-					|| BLI_testextensie(file->relname, ".otf")
-					|| BLI_testextensie(file->relname, ".otc")) {
-				file->flags |= FTFONTFILE;			
-		} else if(BLI_testextensie(file->relname, ".btx")) {
-				file->flags |= BTXFILE;
-		} else if(BLI_testextensie(file->relname, ".dae")) {
-			file->flags |= COLLADAFILE;
-		} else if(BLI_testextensie_array(file->relname, imb_ext_image)
-					|| (has_quicktime && BLI_testextensie_array(file->relname, imb_ext_image_qt))) {
-				file->flags |= IMAGEFILE;			
-		} else if(BLI_testextensie_array(file->relname, imb_ext_movie)) {
-			file->flags |= MOVIEFILE;			
-		} else if(BLI_testextensie_array(file->relname, imb_ext_audio)) {
-			file->flags |= SOUNDFILE;
-		} else if(filelist->filter_glob
-					&& BLI_testextensie_glob(file->relname, filelist->filter_glob)) {
-			file->flags |= OPERATORFILE;
-		}
-	}
-}
 
 void filelist_swapselect(struct FileList* filelist)
 {

source/blender/editors/space_file/filelist.h

@@ -69,7 +69,6 @@ void				filelist_readdir(struct FileList* filelist);
 
 int					filelist_empty(struct FileList* filelist);
 void				filelist_parent(struct FileList* filelist);
-void				filelist_setfiletypes(struct FileList* filelist, short has_quicktime);
 
 
 int					filelist_islibrary (struct FileList* filelist, char* dir, char* group);

source/blender/windowmanager/WM_types.h

@@ -504,7 +504,8 @@ typedef struct wmDropBox {
 	
 	/* if poll survives, operator is called */
 	wmOperatorType *ot;				/* not saved in file, so can be pointer */
-
+	short opcontext;				/* default invoke */
+	
 	struct IDProperty *properties;			/* operator properties, assigned to ptr->data and can be written to a file */
 	struct PointerRNA *ptr;			/* rna pointer to access properties */
 

source/blender/windowmanager/intern/wm_dragdrop.c

@@ -75,6 +75,7 @@ typedef struct wmDropBoxMap {
 	
 } wmDropBoxMap;
 
+/* spaceid/regionid is zero for window drop maps */
 ListBase *WM_dropboxmap_find(const char *idname, int spaceid, int regionid)
 {
 	wmDropBoxMap *dm;
@@ -103,6 +104,7 @@ wmDropBox *WM_dropbox_add(ListBase *lb, const char *idname, int (*poll)(bContext
 	drop->poll= poll;
 	drop->copy= copy;
 	drop->ot= WM_operatortype_find(idname, 0);
+	drop->opcontext= WM_OP_INVOKE_DEFAULT;
 	
 	if(drop->ot==NULL) {
 		MEM_freeN(drop);

source/blender/windowmanager/intern/wm_event_system.c

@@ -1468,8 +1468,14 @@ static int wm_handlers_do(bContext *C, wmEvent *event, ListBase *handlers)
 								if(drop->poll(C, drag, event)) {
 									drop->copy(drag, drop);
 									
-									wm_operator_invoke(C, drop->ot, event, drop->ptr, NULL, FALSE);
+									WM_operator_name_call(C, drop->ot->idname, drop->opcontext, drop->ptr);
+									//wm_operator_invoke(C, drop->ot, event, drop->ptr, NULL, FALSE);
 									action |= WM_HANDLER_BREAK;
+									
+									/* prevent hanging on file read */
+									BLI_freelistN(event->customdata);
+									event->customdata= NULL;
+									event->custom= 0;
 								}
 							}
 						}

source/blender/windowmanager/intern/wm_window.c

@@ -60,6 +60,7 @@
 #include "wm_event_system.h"
 
 #include "ED_screen.h"
+#include "ED_fileselect.h"
 
 #include "PIL_time.h"
 
@@ -413,6 +414,11 @@ void wm_window_add_ghostwindows(bContext* C, wmWindowManager *wm)
 		keymap= WM_keymap_find(wm->defaultconf, "Screen Editing", 0, 0);
 		WM_event_add_keymap_handler(&win->modalhandlers, keymap);
 		
+		/* add drop boxes */
+		{
+			ListBase *lb= WM_dropboxmap_find("Window", 0, 0);
+			WM_event_add_dropbox_handler(&win->handlers, lb);
+		}
 		wm_window_title(wm, win);
 	}
 }
@@ -820,15 +826,17 @@ static int ghost_event_proc(GHOST_EventHandle evt, GHOST_TUserDataPtr private)
 				/* printf("Drop detected\n"); */
 				
 				/* add drag data to wm for paths: */
-				/* need icon type, some dropboxes check for that... see filesel code for this */
 				
 				if(ddd->dataType == GHOST_kDragnDropTypeFilenames) {
 					GHOST_TStringArray *stra= ddd->data;
-					int a;
+					int a, icon;
 					
 					for(a=0; a<stra->count; a++) {
 						printf("drop file %s\n", stra->strings[a]);
-						WM_event_start_drag(C, 0, WM_DRAG_PATH, stra->strings[a], 0.0);
+						/* try to get icon type from extension */
+						icon= ED_file_extension_icon((char *)stra->strings[a]);
+						
+						WM_event_start_drag(C, icon, WM_DRAG_PATH, stra->strings[a], 0.0);
 						/* void poin should point to string, it makes a copy */
 						break; // only one drop element supported now 
 					}