From 6d303b2c4c00c68c730c6ed28f75598ca652e154 Mon Sep 17 00:00:00 2001
From: Olivier Mangin <olivier.mangin@inria.fr>
Date: Thu, 27 Jun 2013 18:35:57 +0200
Subject: [PATCH] Simplifies event mechanism.

- moves RemoveEvent to events
- makes listen a classmethod of the event
---
 papers/commands/remove_cmd.py   |  8 +----
 papers/events.py                | 58 +++++++++++++++++----------------
 papers/plugs/texnote/texnote.py | 11 ++++---
 3 files changed, 38 insertions(+), 39 deletions(-)

diff --git a/papers/commands/remove_cmd.py b/papers/commands/remove_cmd.py
index 9d3ac7d..e1dfea4 100644
--- a/papers/commands/remove_cmd.py
+++ b/papers/commands/remove_cmd.py
@@ -3,13 +3,8 @@ from .. import color
 from .. import configs
 from .helpers import add_references_argument, parse_references
 
-from ..events import Event
+from ..events import RemoveEvent
 
-class RemoveEvent(Event):
-    def __init__(self, config, ui, citekey):
-        self.config = config
-        self.ui = ui
-        self.citekey = citekey
 
 def parser(subparsers, config):
     parser = subparsers.add_parser('remove', help='removes a paper')
@@ -30,4 +25,3 @@ def command(config, ui, references):
             rmevent.send()
 
             rp.remove(c)
-
diff --git a/papers/events.py b/papers/events.py
index 43f3640..05b27a2 100644
--- a/papers/events.py
+++ b/papers/events.py
@@ -1,23 +1,4 @@
-listener = {}
-
-
-def listen(EventClass, *args):
-    def wrap(f):
-        if isinstance(EventClass, type) \
-                and issubclass(EventClass, Event) \
-                and EventClass != Event:
-
-            if not EventClass.__name__ in listener:
-                listener[EventClass.__name__] = []
-            listener[EventClass.__name__].append((f, args))
-
-            # next step allow us to call the function itself without Event raised
-            def wrapped_f(*args):
-                f(*args)
-            return wrapped_f
-        else:
-            raise IOError('{} is not an Event subclass'.format(EventClass))
-    return wrap
+_listener = {}
 
 
 class Event(object):
@@ -29,28 +10,49 @@ class Event(object):
         self.string = string
 
     def send(self):
-        """ This function send the instance of the class, i.e. the event to be sent,
-        to all function that listen to it
+        """ This function sends the instance of the class, i.e. the event
+        to be sent, to all function that listen to it.
         """
-        if self.__class__.__name__ in listener:
-            for f, args in listener[self.__class__.__name__]:
+        if self.__class__.__name__ in _listener:
+            for f, args in _listener[self.__class__.__name__]:
                 f(self, *args)
 
+    @classmethod
+    def listen(cls, *args):
+        def wrap(f):
+            if cls.__name__ not in _listener:
+                _listener[cls.__name__] = []
+            _listener[cls.__name__].append((f, args))
+
+            # next step allow us to call the function itself without Event raised
+            def wrapped_f(*args):
+                f(*args)
+            return wrapped_f
+        return wrap
+
+
+class RemoveEvent(Event):
+    def __init__(self, config, ui, citekey):
+        self.config = config
+        self.ui = ui
+        self.citekey = citekey
+
+
 if __name__ == "__main__":
 
     class TestEvent(Event):
         def print_one(self):
             print 'one'
 
-    @listen(TestEvent, 12, 15)
+    @TestEvent.listen(12, 15)
     def Display(TestEventInstance, nb1, nb2):
         print TestEventInstance.string, nb1, nb2
 
-    @listen(TestEvent)
+    @TestEvent.listen()
     def Helloword(TestEventInstance):
         print 'Helloword'
 
-    @listen(TestEvent)
+    @TestEvent.listen()
     def PrintIt(TestEventInstance):
         TestEventInstance.print_one()
 
@@ -61,7 +63,7 @@ if __name__ == "__main__":
         def add(self, a, b):
             return a + b
 
-    @listen(AddEvent)
+    @AddEvent.listen()
     def DoIt(AddEventInstance):
         print AddEventInstance.add(17, 25)
 
diff --git a/papers/plugs/texnote/texnote.py b/papers/plugs/texnote/texnote.py
index 7528279..36b8776 100644
--- a/papers/plugs/texnote/texnote.py
+++ b/papers/plugs/texnote/texnote.py
@@ -8,8 +8,8 @@ from ... import files
 from ...plugins import PapersPlugin
 from ...commands.helpers import add_references_argument, parse_reference
 
-from ...events import listen
-from ...commands.remove_cmd import RemoveEvent
+from ...events import RemoveEvent
+
 
 TEXNOTE_SECTION = 'texnote'
 TEXNOTE_SAMPLE_FILE = os.path.join(os.path.dirname(__file__), 'note_sample.tex')
@@ -39,14 +39,17 @@ class TexnotePlugin(PapersPlugin):
         print "toto"
 
 
-@listen(RemoveEvent)
+@RemoveEvent.listen()
 def remove(rmevent):
     texplug = TexnotePlugin.get_instance()
     texplug.toto()
     rp = repo.Repository.from_directory(rmevent.config)
     paper = rp.get_paper(parse_reference(rmevent.ui, rp, rmevent.citekey))
     if 'texnote' in paper.metadata:
-        os.remove(paper.metadata['texnote'])
+        try:
+            os.remove(paper.metadata['texnote'])
+        except OSError:
+            pass  # For some reason, the texnote file didn't exist
         paper.metadata.pop('texnote')
         metapath = rp.path_to_paper_file(paper.citekey, 'meta')
         files.save_meta(paper.metadata, metapath)