diff --git a/gdb/python/lib/gdb/dap/server.py b/gdb/python/lib/gdb/dap/server.py index fe1f8bbd428..cba5a308ff1 100644 --- a/gdb/python/lib/gdb/dap/server.py +++ b/gdb/python/lib/gdb/dap/server.py @@ -19,6 +19,7 @@ import heapq import inspect import json import threading +from contextlib import contextmanager from .io import start_json_writer, read_json from .startup import ( @@ -59,24 +60,19 @@ class CancellationHandler: # Methods on this class acquire this lock before proceeding. self.lock = threading.Lock() # The request currently being handled, or None. - self.in_flight = None + self.in_flight_dap_thread = None + self.in_flight_gdb_thread = None self.reqs = [] def starting(self, req): - """Call at the start of the given request. - - Throws the appropriate exception if the request should be - immediately cancelled.""" + """Call at the start of the given request.""" with self.lock: - self.in_flight = req - while len(self.reqs) > 0 and self.reqs[0] <= req: - if heapq.heappop(self.reqs) == req: - raise KeyboardInterrupt() + self.in_flight_dap_thread = req def done(self, req): """Indicate that the request is done.""" with self.lock: - self.in_flight = None + self.in_flight_dap_thread = None def cancel(self, req): """Call to cancel a request. @@ -85,7 +81,7 @@ class CancellationHandler: If the request is in flight, it is interrupted. If the request has not yet been seen, the cancellation is queued.""" with self.lock: - if req == self.in_flight: + if req == self.in_flight_gdb_thread: gdb.interrupt() else: # We don't actually ignore the request here, but in @@ -96,6 +92,29 @@ class CancellationHandler: # to try to check for this. heapq.heappush(self.reqs, req) + @contextmanager + def interruptable_region(self, req): + """Return a new context manager that sets in_flight_gdb_thread to + REQ.""" + if req is None: + # No request is handled in the region, just execute the region. + yield + return + try: + with self.lock: + # If the request is cancelled, don't execute the region. + while len(self.reqs) > 0 and self.reqs[0] <= req: + if heapq.heappop(self.reqs) == req: + raise KeyboardInterrupt() + # Request is being handled by the gdb thread. + self.in_flight_gdb_thread = req + # Execute region. This may be interrupted by gdb.interrupt. + yield + finally: + with self.lock: + # Request is no longer handled by the gdb thread. + self.in_flight_gdb_thread = None + class Server: """The DAP server class.""" @@ -434,13 +453,45 @@ class Invoker(object): exec_and_log(self.cmd) +class Cancellable(object): + + def __init__(self, fn, result_q=None): + self.fn = fn + self.result_q = result_q + with _server.canceller.lock: + self.req = _server.canceller.in_flight_dap_thread + + # This is invoked in the gdb thread to run self.fn. + @in_gdb_thread + def __call__(self): + try: + with _server.canceller.interruptable_region(self.req): + val = self.fn() + if self.result_q is not None: + self.result_q.put(val) + except (Exception, KeyboardInterrupt) as e: + if self.result_q is not None: + # Pass result or exception to caller. + self.result_q.put(e) + elif isinstance(e, KeyboardInterrupt): + # Fn was cancelled. + pass + else: + # Exception happened. Ignore and log it. + err_string = "%s, %s" % (err, type(err)) + thread_log("caught exception: " + err_string) + log_stack() + + def send_gdb(cmd): """Send CMD to the gdb thread. CMD can be either a function or a string. If it is a string, it is passed to gdb.execute.""" if isinstance(cmd, str): cmd = Invoker(cmd) - gdb.post_event(cmd) + + # Post the event and don't wait for the result. + gdb.post_event(Cancellable(cmd)) def send_gdb_with_response(fn): @@ -452,17 +503,12 @@ def send_gdb_with_response(fn): """ if isinstance(fn, str): fn = Invoker(fn) + + # Post the event and wait for the result in result_q. result_q = DAPQueue() - - def message(): - try: - val = fn() - result_q.put(val) - except (Exception, KeyboardInterrupt) as e: - result_q.put(e) - - send_gdb(message) + gdb.post_event(Cancellable(fn, result_q)) val = result_q.get() + if isinstance(val, (Exception, KeyboardInterrupt)): raise val return val