[gnome-builder] build-manager: improve chained cancellation

[Christian Hergert <chergert src gnome org>]

commit 5b0bae38d3fb203755b5557cb996269fa23242b2
Author: Christian Hergert <chergert redhat com>
Date:   Mon Dec 18 15:26:11 2017 -0800

    build-manager: improve chained cancellation
    
    This ensures we don't overwrite self->cancellable except when we
    cancel the GCancellable ourselves. This is important because we
    need to know that our cancellable cannot ever be cancelled
    outside of this module (or we'd have to clear it upon
    ::cancelled).
    
    This fixes an issue where the run manager fails to run a second
    time due to a lingering cancellable who has been cancelled.

 src/libide/buildsystem/ide-build-manager.c |   34 ++++++++++-----------------
 1 files changed, 13 insertions(+), 21 deletions(-)
---
diff --git a/src/libide/buildsystem/ide-build-manager.c b/src/libide/buildsystem/ide-build-manager.c
index 6654f8c..2980f28 100644
--- a/src/libide/buildsystem/ide-build-manager.c
+++ b/src/libide/buildsystem/ide-build-manager.c
@@ -371,6 +371,7 @@ ide_build_manager_invalidate_pipeline (IdeBuildManager *self)
 {
   IdeConfigurationManager *config_manager;
   g_autoptr(GTask) task = NULL;
+  g_autoptr(GCancellable) cancellable = NULL;
   IdeRuntimeManager *runtime_manager;
   IdeConfiguration *config;
   IdeContext *context;
@@ -399,12 +400,9 @@ ide_build_manager_invalidate_pipeline (IdeBuildManager *self)
    * Cancel and clear our previous pipeline and associated components
    * as they are not invalide.
    */
-
-  if (self->cancellable != NULL)
-    {
-      ide_build_manager_cancel (self);
-      g_clear_object (&self->cancellable);
-    }
+  ide_build_manager_cancel (self);
+  cancellable = g_cancellable_new ();
+  dzl_cancellable_chain (cancellable, self->cancellable);
 
   g_clear_object (&self->pipeline);
 
@@ -446,14 +444,13 @@ ide_build_manager_invalidate_pipeline (IdeBuildManager *self)
    * case a further configuration change comes through and we need to
    * tear down the pipeline immediately.
    */
-  self->cancellable = g_cancellable_new ();
-  task = g_task_new (self, self->cancellable, NULL, NULL);
+  task = g_task_new (self, cancellable, NULL, NULL);
   g_task_set_task_data (task, g_object_ref (self->pipeline), g_object_unref);
   g_task_set_priority (task, G_PRIORITY_LOW);
   g_task_set_return_on_cancel (task, TRUE);
   ide_runtime_manager_ensure_async (runtime_manager,
                                     runtime_id,
-                                    self->cancellable,
+                                    cancellable,
                                     ide_build_manager_ensure_runtime_cb,
                                     g_steal_pointer (&task));
 
@@ -1048,6 +1045,7 @@ ide_build_manager_cancel (IdeBuildManager *self)
   g_return_if_fail (IDE_IS_BUILD_MANAGER (self));
 
   cancellable = g_steal_pointer (&self->cancellable);
+  self->cancellable = g_cancellable_new ();
 
   g_debug ("Cancelling [%p] build due to user request", cancellable);
 
@@ -1181,6 +1179,7 @@ ide_build_manager_execute_async (IdeBuildManager     *self,
 
   g_return_if_fail (IDE_IS_BUILD_MANAGER (self));
   g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
+  g_return_if_fail (!g_cancellable_is_cancelled (self->cancellable));
 
   if (cancellable == NULL)
     cancellable = local_cancellable = g_cancellable_new ();
@@ -1207,11 +1206,6 @@ ide_build_manager_execute_async (IdeBuildManager     *self,
       IDE_EXIT;
     }
 
-  g_set_object (&self->cancellable, cancellable);
-
-  if (self->cancellable == NULL)
-    self->cancellable = g_cancellable_new ();
-
   /*
    * Only update our "build time" if we are advancing to IDE_BUILD_PHASE_BUILD,
    * we don't really care about "builds" for configure stages and less.
@@ -1236,7 +1230,7 @@ ide_build_manager_execute_async (IdeBuildManager     *self,
       context = ide_object_get_context (IDE_OBJECT (self));
       buffer_manager = ide_context_get_buffer_manager (context);
       ide_buffer_manager_save_all_async (buffer_manager,
-                                         self->cancellable,
+                                         cancellable,
                                          ide_build_manager_save_all_cb,
                                          g_steal_pointer (&task));
       IDE_EXIT;
@@ -1339,6 +1333,7 @@ ide_build_manager_clean_async (IdeBuildManager     *self,
 
   g_return_if_fail (IDE_IS_BUILD_MANAGER (self));
   g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
+  g_return_if_fail (!g_cancellable_is_cancelled (self->cancellable));
 
   if (cancellable == NULL)
     cancellable = local_cancellable = g_cancellable_new ();
@@ -1359,15 +1354,13 @@ ide_build_manager_clean_async (IdeBuildManager     *self,
       IDE_EXIT;
     }
 
-  g_set_object (&self->cancellable, cancellable);
-
   self->diagnostic_count = 0;
   self->error_count = 0;
   self->warning_count = 0;
 
   ide_build_pipeline_clean_async (self->pipeline,
                                   phase,
-                                  self->cancellable,
+                                  cancellable,
                                   ide_build_manager_clean_cb,
                                   g_steal_pointer (&task));
 
@@ -1460,6 +1453,7 @@ ide_build_manager_rebuild_async (IdeBuildManager     *self,
 
   g_return_if_fail (IDE_IS_BUILD_MANAGER (self));
   g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
+  g_return_if_fail (!g_cancellable_is_cancelled (self->cancellable));
 
   if (cancellable == NULL)
     cancellable = local_cancellable = g_cancellable_new ();
@@ -1480,11 +1474,9 @@ ide_build_manager_rebuild_async (IdeBuildManager     *self,
       IDE_EXIT;
     }
 
-  g_set_object (&self->cancellable, cancellable);
-
   ide_build_pipeline_rebuild_async (self->pipeline,
                                     phase,
-                                    self->cancellable,
+                                    cancellable,
                                     ide_build_manager_rebuild_cb,
                                     g_steal_pointer (&task));