[gnome-builder: 6/7] jedi: improve interactivity by tracking cancellation

[Christian Hergert <chergert src gnome org>]

commit d3c06ebaec8d011c1c5b2bc1363fe7504be62530
Author: Christian Hergert <christian hergert me>
Date:   Mon Aug 24 16:38:09 2015 -0700

    jedi: improve interactivity by tracking cancellation
    
    We still have more to do here in terms of making this interactive.
    Python really blocks us at some inopportune moments. Getting this out
    of process will also likely help. To do that, we need to finish the
    autocompletion API for G-C-A and do the same wrapping trick we
    do for Clang completion (but with GVariant).

 plugins/jedi/jedi_plugin.py |   28 +++++++++++++++++++++++-----
 1 files changed, 23 insertions(+), 5 deletions(-)
---
diff --git a/plugins/jedi/jedi_plugin.py b/plugins/jedi/jedi_plugin.py
index 91b2205..2d620fa 100644
--- a/plugins/jedi/jedi_plugin.py
+++ b/plugins/jedi/jedi_plugin.py
@@ -81,6 +81,8 @@ import threading
 
 
 class CompletionThread(threading.Thread):
+    cancelled = False
+
     def __init__(self, provider, context, text, line, column, filename):
         super().__init__()
         self._provider = provider
@@ -93,14 +95,20 @@ class CompletionThread(threading.Thread):
 
     def run(self):
         try:
-            script = jedi.Script(self._text, self._line, self._column, self._filename)
-            self._completions = [JediCompletionProposal(self._provider, self._context, info)
-                                 for info in script.completions()]
+            if not self.cancelled:
+                script = jedi.Script(self._text, self._line, self._column, self._filename)
+                completions = []
+                if not self.cancelled:
+                    for info in script.completions():
+                        completion = JediCompletionProposal(self._provider, self._context, info)
+                        completions.append(completion)
+                self._completions = completions
         finally:
             self.complete_in_idle()
 
     def _complete(self):
-        self._context.add_proposals(self._provider, self._completions, True)
+        if not self.cancelled:
+            self._context.add_proposals(self._provider, self._completions, True)
 
     def complete_in_idle(self):
         GLib.timeout_add(0, self._complete)
@@ -109,6 +117,8 @@ class CompletionThread(threading.Thread):
 class JediCompletionProvider(Ide.Object,
                              GtkSource.CompletionProvider,
                              Ide.CompletionProvider):
+    thread = None
+
     def do_get_name(self):
         return 'Jedi Provider'
 
@@ -123,6 +133,8 @@ class JediCompletionProvider(Ide.Object,
         _, iter = context.get_iter()
         buffer = iter.get_buffer()
 
+        self.thread = None
+
         # ignore completions if we are following whitespace.
         copy = iter.copy()
         copy.set_line_offset(0)
@@ -142,7 +154,13 @@ class JediCompletionProvider(Ide.Object,
         line = iter.get_line() + 1
         column = iter.get_line_offset()
 
-        CompletionThread(self, context, text, line, column, filename).start()
+        context.connect('cancelled', lambda *_: self._cancelled())
+        self.thread = CompletionThread(self, context, text, line, column, filename)
+        self.thread.start()
+
+    def _cancelled(self):
+        if self.thread is not None:
+            self.thread.cancelled = True
 
     def do_get_activiation(self):
         return GtkSource.CompletionActivation.INTERACTIVE