_state.py: Only use a single place of truth for the start time

This moves all implementations of 'start_time' into a single place
for easier handling and removing roundtrips of notifications

5 files changed, 19 insertions, 19 deletions

diff --git a/src/buildstream/_frontend/app.py b/src/buildstream/_frontend/app.py
index e7831dac3..3160e8b1e 100644
--- a/src/buildstream/_frontend/app.py
+++ b/src/buildstream/_frontend/app.py
@@ -311,7 +311,7 @@ class App:
 
                 # Print a nice summary if this is a session
                 if session_name:
-                    elapsed = self.stream.elapsed_time
+                    elapsed = self._state.elapsed_time()
 
                     if isinstance(e, StreamError) and e.terminated:  # pylint: disable=no-member
                         self._message(MessageType.WARN, session_name + " Terminated", elapsed=elapsed)
@@ -339,7 +339,7 @@ class App:
             else:
                 # No exceptions occurred, print session time and summary
                 if session_name:
-                    self._message(MessageType.SUCCESS, session_name, elapsed=self.stream.elapsed_time)
+                    self._message(MessageType.SUCCESS, session_name, elapsed=self._state.elapsed_time())
                     if self._started:
                         self._print_summary()
 
diff --git a/src/buildstream/_frontend/status.py b/src/buildstream/_frontend/status.py
index a3f0d8aa7..e0505b45b 100644
--- a/src/buildstream/_frontend/status.py
+++ b/src/buildstream/_frontend/status.py
@@ -109,7 +109,7 @@ class Status:
         if not self._term_caps:
             return
 
-        elapsed = self._stream.elapsed_time
+        elapsed = self._state.elapsed_time()
 
         self.clear()
         self._check_term_width()
diff --git a/src/buildstream/_scheduler/scheduler.py b/src/buildstream/_scheduler/scheduler.py
index a7d3ff471..38d656623 100644
--- a/src/buildstream/_scheduler/scheduler.py
+++ b/src/buildstream/_scheduler/scheduler.py
@@ -58,7 +58,6 @@ class NotificationType(FastEnum):
     TICK = "tick"
     TERMINATE = "terminate"
     QUIT = "quit"
-    SCHED_START_TIME = "sched_start_time"
     RUNNING = "running"
     TERMINATED = "terminated"
     SUSPEND = "suspend"
@@ -135,7 +134,6 @@ class Scheduler:
         # Private members
         #
         self._active_jobs = []  # Jobs currently being run in the scheduler
-        self._starttime = start_time  # Initial application start time
         self._suspendtime = None  # Session time compensation for suspended state
         self._queue_jobs = True  # Whether we should continue to queue jobs
         self._state = state
@@ -364,7 +362,7 @@ class Scheduler:
         self._active_jobs.append(job)
         job.start()
 
-        self._state.add_task(job.action_name, job.name, self._state.elapsed_time(start_time=self._starttime))
+        self._state.add_task(job.action_name, job.name, self._state.elapsed_time())
 
     # _sched_queue_jobs()
     #
@@ -485,9 +483,8 @@ class Scheduler:
                 job.resume()
             self.suspended = False
             # Notify that we're unsuspended
+            self._state.offset_start_time(datetime.datetime.now() - self._suspendtime)
             self._notify(Notification(NotificationType.SUSPENDED))
-            self._starttime += datetime.datetime.now() - self._suspendtime
-            self._notify(Notification(NotificationType.SCHED_START_TIME, time=self._starttime))
             self._suspendtime = None
 
     # _interrupt_event():
diff --git a/src/buildstream/_state.py b/src/buildstream/_state.py
index ec4f895fe..b8479e2b9 100644
--- a/src/buildstream/_state.py
+++ b/src/buildstream/_state.py
@@ -354,6 +354,20 @@ class State:
             start_time = self._session_start or time_now
         return time_now - start_time
 
+    # offset_start_time()
+    #
+    # Update the 'start' time of the application by a given offset
+    #
+    # This allows modifying the time spent building when BuildStream
+    # gets paused then restarted, to give an accurate view of the real
+    # time spend building.
+    #
+    # Args:
+    #   offset: the offset to add to the start time
+    #
+    def offset_start_time(self, offset: datetime.timedelta) -> None:
+        self._session_start += offset
+
 
 # _Task
 #
diff --git a/src/buildstream/_stream.py b/src/buildstream/_stream.py
index 277ea7394..fb0b2f6e1 100644
--- a/src/buildstream/_stream.py
+++ b/src/buildstream/_stream.py
@@ -90,7 +90,6 @@ class Stream:
         self._pipeline = None
         self._state = State(session_start)  # Owned by Stream, used by Core to set state
         self._notification_queue = deque()
-        self._starttime = session_start  # Synchronised with Scheduler's relative start time
 
         context.messenger.set_state(self._state)
 
@@ -1081,14 +1080,6 @@ class Stream:
     def terminated(self):
         return self._scheduler_terminated
 
-    # elapsed_time
-    #
-    # Elapsed time since the session start
-    #
-    @property
-    def elapsed_time(self):
-        return self._state.elapsed_time(start_time=self._starttime)
-
     # terminate()
     #
     # Terminate jobs
@@ -1661,8 +1652,6 @@ class Stream:
             self._interrupt_callback()
         elif notification.notification_type == NotificationType.TICK:
             self._ticker_callback()
-        elif notification.notification_type == NotificationType.SCHED_START_TIME:
-            self._starttime = notification.time
         elif notification.notification_type == NotificationType.RUNNING:
             self._scheduler_running = not self._scheduler_running
         elif notification.notification_type == NotificationType.TERMINATED: