event/cooker/runqueue: Add ability to interrupt longer running code

Bitbake is now able to understand when a UI wants it to stop the current
processing. There are some long running functions which currently have no
mechanism to interrupt them however.

This patch adds a call, bb.event.check_for_interrupts(d) which can be
placed in long running code and allows an internal state flag within
bitbake to be checked. If set, that flag will trigger an exit.

This means that Ctrl+C can be made to work in a variety of places where
it currently would not.

Long running event handlers in OE-Core can also then benefit from this
new approach with the addition of the function call as well.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

3 files changed, 30 insertions, 0 deletions

diff --git a/lib/bb/cooker.py b/lib/bb/cooker.py
index b673fe10e..c631ec7e6 100644
--- a/lib/bb/cooker.py
+++ b/lib/bb/cooker.py
@@ -345,6 +345,7 @@ class BBCooker:
         elif signum == signal.SIGHUP:
             bb.warn("Cooker received SIGHUP, shutting down...")
         self.state = state.forceshutdown
+        bb.event._should_exit.set()
 
     def setFeatures(self, features):
         # we only accept a new feature set if we're in state initial, so we can reset without problems
@@ -1520,6 +1521,7 @@ class BBCooker:
             msg = None
             interrupted = 0
             if halt or self.state == state.forceshutdown:
+                bb.event._should_exit.set()
                 rq.finish_runqueue(True)
                 msg = "Forced shutdown"
                 interrupted = 2
@@ -1760,6 +1762,7 @@ class BBCooker:
             self.state = state.forceshutdown
         else:
             self.state = state.shutdown
+        bb.event._should_exit.set()
 
         if self.parser:
             self.parser.shutdown(clean=False)
@@ -1770,6 +1773,7 @@ class BBCooker:
             self.parser.shutdown(clean=False)
             self.parser.final_cleanup()
         self.state = state.initial
+        bb.event._should_exit.clear()
 
     def reset(self):
         if hasattr(bb.parse, "siggen"):
diff --git a/lib/bb/event.py b/lib/bb/event.py
index 8b05f93e2..37cc630c6 100644
--- a/lib/bb/event.py
+++ b/lib/bb/event.py
@@ -69,6 +69,7 @@ _eventfilter = None
 _uiready = False
 _thread_lock = threading.Lock()
 _heartbeat_enabled = False
+_should_exit = threading.Event()
 
 def enable_threadlock():
     # Always needed now
@@ -86,6 +87,16 @@ def disable_heartbeat():
     global _heartbeat_enabled
     _heartbeat_enabled = False
 
+#
+# In long running code, this function should be called periodically
+# to check if we should exit due to an interuption (.e.g Ctrl+C from the UI)
+#
+def check_for_interrupts(d):
+    global _should_exit
+    if _should_exit.is_set():
+        bb.warn("Exiting due to interrupt.")
+        raise bb.BBHandledException()
+
 def execute_handler(name, handler, event, d):
     event.data = d
     try:
diff --git a/lib/bb/runqueue.py b/lib/bb/runqueue.py
index e5bd9311f..e629ab7e7 100644
--- a/lib/bb/runqueue.py
+++ b/lib/bb/runqueue.py
@@ -655,6 +655,7 @@ class RunQueueData:
 
         self.init_progress_reporter.start()
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         # Step A - Work out a list of tasks to run
         #
@@ -803,6 +804,7 @@ class RunQueueData:
         #self.dump_data()
 
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         # Resolve recursive 'recrdeptask' dependencies (Part B)
         #
@@ -899,6 +901,7 @@ class RunQueueData:
             self.runtaskentries[tid].depends.difference_update(recursivetasksselfref)
 
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         #self.dump_data()
 
@@ -980,6 +983,7 @@ class RunQueueData:
                 mark_active(tid, 1)
 
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         # Step C - Prune all inactive tasks
         #
@@ -1019,6 +1023,7 @@ class RunQueueData:
                 bb.msg.fatal("RunQueue", "Could not find any tasks with the tasknames %s to run within the recipes of the taskgraphs of the targets %s" % (str(self.cooker.configuration.runall), str(self.targets)))
 
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         # Handle runonly
         if self.cooker.configuration.runonly:
@@ -1059,6 +1064,7 @@ class RunQueueData:
         logger.verbose("Assign Weightings")
 
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         # Generate a list of reverse dependencies to ease future calculations
         for tid in self.runtaskentries:
@@ -1066,6 +1072,7 @@ class RunQueueData:
                 self.runtaskentries[dep].revdeps.add(tid)
 
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         # Identify tasks at the end of dependency chains
         # Error on circular dependency loops (length two)
@@ -1082,12 +1089,14 @@ class RunQueueData:
         logger.verbose("Compute totals (have %s endpoint(s))", len(endpoints))
 
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         # Calculate task weights
         # Check of higher length circular dependencies
         self.runq_weight = self.calculate_task_weights(endpoints)
 
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         # Sanity Check - Check for multiple tasks building the same provider
         for mc in self.dataCaches:
@@ -1188,6 +1197,7 @@ class RunQueueData:
 
         self.init_progress_reporter.next_stage()
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         # Iterate over the task list looking for tasks with a 'setscene' function
         self.runq_setscene_tids = set()
@@ -1200,6 +1210,7 @@ class RunQueueData:
                 self.runq_setscene_tids.add(tid)
 
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         # Invalidate task if force mode active
         if self.cooker.configuration.force:
@@ -1216,6 +1227,7 @@ class RunQueueData:
                     invalidate_task(fn + ":" + st, True)
 
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         # Create and print to the logs a virtual/xxxx -> PN (fn) table
         for mc in taskData:
@@ -1228,6 +1240,7 @@ class RunQueueData:
                 bb.parse.siggen.tasks_resolved(virtmap, virtpnmap, self.dataCaches[mc])
 
         self.init_progress_reporter.next_stage()
+        bb.event.check_for_interrupts(self.cooker.data)
 
         bb.parse.siggen.set_setscene_tasks(self.runq_setscene_tids)
 
@@ -1240,6 +1253,7 @@ class RunQueueData:
                     dealtwith.add(tid)
                     todeal.remove(tid)
                     self.prepare_task_hash(tid)
+                bb.event.check_for_interrupts(self.cooker.data)
 
         bb.parse.siggen.writeout_file_checksum_cache()
 
@@ -1483,6 +1497,7 @@ class RunQueue:
         """
 
         retval = True
+        bb.event.check_for_interrupts(self.cooker.data)
 
         if self.state is runQueuePrepare:
             # NOTE: if you add, remove or significantly refactor the stages of this