ftrace: Report unavailable events all at once

Emit one warning message or one exception referring to the whole list of
unavailable events, rather than spreading it through multiple calls. In strict
mode, this allows the user to fix the whole list of bogus events at once rather
than incrementally.

Signed-off-by: Douglas RAILLARD <douglas.raillard@arm.com>

devlib/trace/ftrace.py

@@ -125,21 +125,33 @@ class FtraceCollector(TraceCollector):
             self.target_binary = 'trace-cmd'
 
         # Validate required events to be traced
-        selected_events = []
-        for event in self.events:
-            # Convert globs supported by FTrace into valid regexp globs
-            _event = event
-            if event[0] != '*':
-                _event = '*' + event
-            event_re = re.compile(_event.replace('*', '.*'))
-            # Select events matching the required ones
-            if not list(filter(event_re.match, self.available_events)):
-                message = 'Event [{}] not available for tracing'.format(event)
+        def event_to_regex(event):
+            if not event.startswith('*'):
+                event = '*' + event
+
+            return re.compile(event.replace('*', '.*'))
+
+        def event_is_in_list(event, events):
+            return any(
+                event_to_regex(event).match(_event)
+                for _event in events
+            )
+
+        unavailable_events = [
+            event
+            for event in self.events
+            if not event_is_in_list(event, self.available_events)
+        ]
+        if unavailable_events:
+            message = 'Events not available for tracing: {}'.format(
+                ', '.join(unavailable_events)
+            )
             if strict:
                 raise TargetStableError(message)
-                self.target.logger.warning(message)
             else:
-                selected_events.append(event)
+                self.target.logger.warning(message)
+
+        selected_events = sorted(set(self.events) - set(unavailable_events))
 
         if self.tracer and self.tracer not in self.available_tracers:
             raise TargetStableError('Unsupported tracer "{}". Available tracers: {}'.format(