UPBGE: Add all libraries path for python component import.

UPBGE and BFBGE are setting in sys.path the path to all the libraries (blend files)
used. blender bpy python doesn't do that.
As python component construction should behave like in UPBGE as they will be used
in UPBGE, the path of the current library was added in sys.path. But in case where
the python component script comes from an other library the construction failed.

To solve this issue we follow exactly UPBGE/BFBGE behaviour about sys.path but for
the python component construction. This behaviour consists in iterating over all
the libraries contained in main->library, then translate the path and insert it to
sys.path. When the python component construction is finished or interrupted, the
libraries are again iterated and we look for index item of the library path in
sys.path, if these index are valid the items are removed safely.

Fix issue #307.

source/blender/blenkernel/intern/python_component.c

@@ -354,7 +354,7 @@ static void create_properties(PythonComponent *pycomp, PyObject *cls)
 }
 #endif /* WITH_PYTHON */
 
-static bool load_component(PythonComponent *pc, ReportList *reports, char *filename)
+static bool load_component(PythonComponent *pc, ReportList *reports, Main *maggie)
 {
 #ifdef WITH_PYTHON
 
@@ -371,7 +371,16 @@ static bool load_component(PythonComponent *pc, ReportList *reports, char *filen
 		Py_XDECREF(item); \
 		PyDict_DelItemString(sys_modules, "bge"); \
 		PyDict_DelItemString(sys_modules, "bge.types"); \
-		PySequence_DelItem(sys_path, 0); \
+		for (Library *lib = (Library *)maggie->library.first; lib; lib = (Library *)lib->id.next) { \
+			int index; \
+			BLI_split_dir_part(lib->filepath, path, sizeof(path)); \
+			pypath = PyC_UnicodeFromByte(path); \
+			index = PySequence_Index(sys_path, pypath); \
+			/* Safely remove the value by finding their index. */ \
+			if (index != -1) { \
+				PySequence_DelItem(sys_path, index); \
+			} \
+		} \
 		PyGILState_Release(state); \
 		return value;
 
@@ -383,10 +392,13 @@ static bool load_component(PythonComponent *pc, ReportList *reports, char *filen
 
 	// Set the current file directory do import path to allow extern modules.
 	sys_path = PySys_GetObject("path");
-	BLI_split_dir_part(filename, path, sizeof(path));
-	pypath = PyC_UnicodeFromByte(path);
-	PyList_Insert(sys_path, 0, pypath);
-
+	/* Add to sys.path the path to all the used library to follow game engine sys.path management.
+	 * These path are remove later in FINISH. */
+	for (Library *lib = (Library *)maggie->library.first; lib; lib = (Library *)lib->id.next) {
+		BLI_split_dir_part(lib->filepath, path, sizeof(path));
+		pypath = PyC_UnicodeFromByte(path);
+		PyList_Insert(sys_path, 0, pypath);
+	}
 	// Setup BGE fake module and submodule.
 	sys_modules = PyThreadState_GET()->interp->modules;
 	bgemod = PyModule_Create(&bge_module_def);
@@ -469,7 +481,7 @@ PythonComponent *BKE_python_component_new(char *import, ReportList *reports, bCo
 	}
 
 	// Try load the component.
-	if (!load_component(pc, reports, CTX_data_main(context)->name)) {
+	if (!load_component(pc, reports, CTX_data_main(context))) {
 		BKE_python_component_free(pc);
 		return NULL;
 	}
@@ -479,7 +491,7 @@ PythonComponent *BKE_python_component_new(char *import, ReportList *reports, bCo
 
 void BKE_python_component_reload(PythonComponent *pc, ReportList *reports, bContext *context)
 {
-	load_component(pc, reports, CTX_data_main(context)->name);
+	load_component(pc, reports, CTX_data_main(context));
 }
 
 static PythonComponent *copy_component(PythonComponent *comp)