ust_service_check: proper treatment of files in sub-directories

We must not only consider files in the current directory (ADF.USIM)
but also in its sub-directories.  This requires us to be able to
determine the path we need to traverse between the currently selected
file (EF.UST) and the respective file in some other directory,
which is implemented via CardFile.build_select_path_to().

Change-Id: I61797fefa9dafa36a8a62c11aa2cfaeecb015740

pySim/filesystem.py

@@ -115,6 +115,34 @@ class CardFile(object):
             ret.append(elem)
         return ret
 
+    def fully_qualified_path_fobj(self) -> List['CardFile']:
+        """Return fully qualified path to file as list of CardFile instance references."""
+        if self.parent and self.parent != self:
+            ret = self.parent.fully_qualified_path_fobj()
+        else:
+            ret = []
+        if self:
+            ret.append(self)
+        return ret
+
+    def build_select_path_to(self, target: 'CardFile') -> Optional[List['CardFile']]:
+        """Build the relative sequence of files we need to traverse to get from us to 'target'."""
+        cur_fqpath = self.fully_qualified_path_fobj()
+        target_fqpath = target.fully_qualified_path_fobj()
+        inter_path = []
+        cur_fqpath.pop()  # drop last element (currently selected file, doesn't need re-selection
+        cur_fqpath.reverse()
+        for ce in cur_fqpath:
+            inter_path.append(ce)
+            for i in range(0, len(target_fqpath)-1):
+                te = target_fqpath[i]
+                if te == ce:
+                    for te2 in target_fqpath[i+1:]:
+                        inter_path.append(te2)
+                    # we found our common ancestor
+                    return inter_path
+        return None
+
     def get_mf(self) -> Optional['CardMF']:
         """Return the MF (root) of the file system."""
         if self.parent == None:
@@ -1337,6 +1365,45 @@ class RuntimeState(object):
         self.selected_file = f
         return select_resp
 
+    def _select_pre(self, cmd_app):
+        # unregister commands of old file
+        if cmd_app and self.selected_file.shell_commands:
+            for c in self.selected_file.shell_commands:
+                cmd_app.unregister_command_set(c)
+
+    def _select_post(self, cmd_app):
+        # register commands of new file
+        if cmd_app and self.selected_file.shell_commands:
+            for c in self.selected_file.shell_commands:
+                cmd_app.register_command_set(c)
+
+    def select_file(self, file: CardFile, cmd_app=None):
+        """Select a file (EF, DF, ADF, MF, ...).
+
+        Args:
+            file : CardFile [or derived class] instance
+            cmd_app : Command Application State (for unregistering old file commands)
+        """
+        # we need to find a path from our self.selected_file to the destination
+        inter_path = self.selected_file.build_select_path_to(file)
+        if not inter_path:
+            raise RuntimeError('Cannot determine path from %s to %s' % (self.selected_file, file))
+
+        self._select_pre(cmd_app)
+
+        for p in inter_path:
+            try:
+                if isinstance(p, CardADF):
+                    (data, sw) = self.card.select_adf_by_aid(p.aid)
+                else:
+                    (data, sw) = self.card._scc.select_file(p.fid)
+                self.selected_file = p
+            except SwMatchError as swm:
+                self._select_post(cmd_app)
+                raise(swm)
+
+        self._select_post(cmd_app)
+
     def select(self, name: str, cmd_app=None):
         """Select a file (EF, DF, ADF, MF, ...).
 
@@ -1348,10 +1415,7 @@ class RuntimeState(object):
         if is_hex(name):
             name = name.lower()
 
-        # unregister commands of old file
-        if cmd_app and self.selected_file.shell_commands:
-            for c in self.selected_file.shell_commands:
-                cmd_app.unregister_command_set(c)
+        self._select_pre(cmd_app)
 
         if name in sels:
             f = sels[name]
@@ -1372,11 +1436,7 @@ class RuntimeState(object):
         # store the decoded FCP for later reference
         self.selected_file_fcp = select_resp
 
-        # register commands of new file
-        if cmd_app and self.selected_file.shell_commands:
-            for c in self.selected_file.shell_commands:
-                cmd_app.register_command_set(c)
-
+        self._select_post(cmd_app)
         return select_resp
 
     def status(self):

pySim/ts_31_102.py

@@ -608,12 +608,8 @@ class EF_UServiceTable(TransparentEF):
                 for f in files_by_service[s]:
                     should_exist = f.should_exist_for_services(active_services)
                     try:
-                        (data, sw) = cmd.card._scc.select_file(f.fid)
+                        cmd.rs.select_file(f)
                         exists = True
-                        fcp = f.decode_select_response(data)
-                        # if we just selected a directory, go back
-                        if fcp['file_descriptor']['file_type'] == 'df':
-                            cmd.card._scc.select_parent_df()
                     except SwMatchError as e:
                         sw = str(e)
                         exists = False
@@ -625,7 +621,7 @@ class EF_UServiceTable(TransparentEF):
                             cmd.perror("  ERROR: File %s is not selectable (%s) but should!" %  (f, sw))
         finally:
             # re-select the EF.UST
-            cmd.card._scc.select_file(self.fid)
+            cmd.rs.select_file(self)
         return num_problems
 
 class EF_UST(EF_UServiceTable):