first pass at signal handling

thomasballinger · thomasballinger · commit fb4e0ecb495e · 2013-11-06T13:00:19.000-05:00
--HG--
branch : scroll-frontend
diff --git a/bpython/scrollfrontend/coderunner.py b/bpython/scrollfrontend/coderunner.py
@@ -5,6 +5,9 @@
 import threading
 import logging
 
+class SigintHappened(object):
+    pass
+
 class CodeRunner(object):
     """Runs user code in an interpreter, taking care of stdout/in/err"""
     def __init__(self, interp=None, stuff_a_refresh_request=lambda:None):
@@ -15,6 +18,8 @@ def __init__(self, interp=None, stuff_a_refresh_request=lambda:None):
         self.responses_for_code_thread = Queue.Queue(maxsize=1)
         self.stuff_a_refresh_request = stuff_a_refresh_request
         self.code_is_waiting = False
+        self.sigint_happened = False
+        self.orig_sigint_handler = None
 
     @property
     def running(self):
@@ -42,24 +47,39 @@ def run_code(self, for_code=None):
             assert self.source is not None
             self.code_thread = threading.Thread(target=self._blocking_run_code, name='codethread')
             self.code_thread.daemon = True
+            self.orig_sigint_handler = signal.getsignal(signal.SIGINT)
+            signal.signal(signal.SIGINT, signal.default_int_handler)
             self.code_thread.start()
         else:
             assert self.code_is_waiting
             self.code_is_waiting = False
-            self.responses_for_code_thread.put(for_code)
+            signal.signal(signal.SIGINT, signal.default_int_handler)
+            if self.sigint_happened:
+                self.sigint_happened = False
+                self.responses_for_code_thread.put(SigintHappened)
+            else:
+                self.responses_for_code_thread.put(for_code)
 
         request = self.requests_from_code_thread.get()
+        signal.signal(signal.SIGINT, self.sigint_handler_while_fufilling_code_request)
         if request in ['wait', 'refresh']:
             self.code_is_waiting = True
             if request == 'refresh':
                 self.stuff_a_refresh_request()
             return False
         elif request in ['done', 'unfinished']:
             self._unload_code()
+            if self.orig_sigint_handler:
+                signal.signal(signal.SIGINT, self.orig_sigint_handler)
+            self.orig_sigint_handler = None
             return request
         else:
             raise ValueError("Not a valid request_from_code_thread value: %r" % request)
 
+    def sigint_handler_while_fufilling_code_request(self, *args):
+        logging.debug('while fufilling code request sigint handler running!')
+        self.sigint_happened = True
+
     def _blocking_run_code(self):
         unfinished = self.interp.runsource(self.source)
         self.requests_from_code_thread.put('unfinished' if unfinished else 'done')
@@ -70,12 +90,18 @@ def wait_and_get_value(self):
         Nothing means calls to run_code must be...
         """
         self.requests_from_code_thread.put('wait')
-        return self.responses_for_code_thread.get()
+        value = self.responses_for_code_thread.get()
+        if value is SigintHappened:
+            raise KeyboardInterrupt()
+        return value
 
     def refresh_and_get_value(self):
         """Returns the argument passed in to .run_code(for_code) """
         self.requests_from_code_thread.put('refresh')
-        return self.responses_for_code_thread.get()
+        value = self.responses_for_code_thread.get()
+        if value is SigintHappened:
+            raise KeyboardInterrupt()
+        return value
 
 class FakeOutput(object):
     def __init__(self, coderunner, please):
@@ -85,7 +111,7 @@ def write(self, *args, **kwargs):
         self.please(*args, **kwargs)
         return self.coderunner.refresh_and_get_value()
 
-if __name__ == '__main__':
+def test_simple():
     orig_stdout = sys.stdout
     orig_stderr = sys.stderr
     c = CodeRunner(stuff_a_refresh_request=lambda: orig_stdout.flush() or orig_stderr.flush())
@@ -95,3 +121,18 @@ def write(self, *args, **kwargs):
     c.run_code()
     c.run_code()
     c.run_code()
+
+def test_exception():
+    orig_stdout = sys.stdout
+    orig_stderr = sys.stderr
+    c = CodeRunner(stuff_a_refresh_request=lambda: orig_stdout.flush() or orig_stderr.flush())
+    def ctrlc():
+        raise KeyboardInterrupt()
+    stdout = FakeOutput(c, lambda x: ctrlc())
+    sys.stdout = stdout
+    c.load_code('1 + 1')
+    c.run_code()
+
+if __name__ == '__main__':
+    test_simple()
+
diff --git a/bpython/scrollfrontend/repl.py b/bpython/scrollfrontend/repl.py
@@ -21,7 +21,7 @@
 from fmtstr.fmtstr import fmtstr, FmtStr
 from fmtstr.bpythonparse import parse as bpythonparse
 from fmtstr.bpythonparse import func_for_letter, color_for_letter
-from fmtstr.events import pp_event
+from fmtstr.events import pp_event, SigIntEvent
 
 from bpython.scrollfrontend.manual_readline import char_sequences as rl_char_sequences
 from bpython.scrollfrontend.manual_readline import get_updated_char_sequences
@@ -198,6 +198,10 @@ def process_event(self, e):
             return
         self.last_events.append(e)
         self.last_events.pop(0)
+        if isinstance(e, events.SigIntEvent):
+            logging.debug('received sigint event')
+            self.keyboard_interrupt()
+            return
         if isinstance(e, events.WindowChangeEvent):
             logging.debug('window change to %d %d', e.width, e.height)
             self.width, self.height = e.width, e.height
@@ -447,6 +451,14 @@ def run_code_and_maybe_finish(self, for_code=None):
             self.cursor_offset_in_line = len(self._current_line)
             self.done = not unfinished
 
+    def keyboard_interrupt(self):
+        self.display_lines.extend(paint.display_linize(self.current_cursor_line, self.width))
+        self.display_lines.extend(paint.display_linize("KeyboardInterrupt", self.width))
+        self.saved_indent = 0
+        self._current_line = ''
+        self.cursor_offset_in_line = len(self._current_line)
+        self.done = True
+
     def unhighlight_paren(self):
         """modify line in self.display_buffer to unhighlight a paren if possible
 
