From 1c1b5096be2a636f3b1720c59fc252cbad733787 Mon Sep 17 00:00:00 2001
From: Kay Kurokawa <kay@lbry.io>
Date: Tue, 20 Jun 2017 15:03:17 -0400
Subject: [PATCH] use LoopingCall in SingleProgressManager to simplify it

---
 .../core/client/StandaloneBlobDownloader.py   | 41 +++++--------------
 lbrynet/core/utils.py                         |  7 ++++
 2 files changed, 18 insertions(+), 30 deletions(-)

diff --git a/lbrynet/core/client/StandaloneBlobDownloader.py b/lbrynet/core/client/StandaloneBlobDownloader.py
index e4f44ca6e..1e247b0a2 100644
--- a/lbrynet/core/client/StandaloneBlobDownloader.py
+++ b/lbrynet/core/client/StandaloneBlobDownloader.py
@@ -6,10 +6,10 @@ from lbrynet.core.client.BlobRequester import BlobRequester
 from lbrynet.core.client.ConnectionManager import ConnectionManager
 from lbrynet.core.client.DownloadManager import DownloadManager
 from lbrynet.core.Error import InvalidBlobHashError
-from lbrynet.core.utils import is_valid_blobhash
+from lbrynet.core.utils import is_valid_blobhash, safe_start_looping_call, safe_stop_looping_call
 from twisted.python.failure import Failure
 from twisted.internet import defer
-
+from twisted.internet import LoopingCall
 
 log = logging.getLogger(__name__)
 
@@ -34,34 +34,24 @@ class SingleBlobMetadataHandler(object):
 class SingleProgressManager(object):
     def __init__(self, finished_callback, download_manager):
         self.finished_callback = finished_callback
-        self.finished = False
         self.download_manager = download_manager
-        self._next_check_if_finished = None
+
+        self.checker = LoopingCall(self._check_if_finished) 
 
     def start(self):
-
-        from twisted.internet import reactor
-
-        assert self._next_check_if_finished is None
-        self._next_check_if_finished = reactor.callLater(0, self._check_if_finished)
+        safe_start_looping_call(self.checker,1) 
         return defer.succeed(True)
 
     def stop(self):
-        if self._next_check_if_finished is not None:
-            self._next_check_if_finished.cancel()
-            self._next_check_if_finished = None
+        safe_stop_looping_call(self.checker)
         return defer.succeed(True)
 
     def _check_if_finished(self):
-
-        from twisted.internet import reactor
-
-        self._next_check_if_finished = None
-        if self.finished is False:
-            if self.stream_position() == 1:
-                self.blob_downloaded(self.download_manager.blobs[0], 0)
-            else:
-                self._next_check_if_finished = reactor.callLater(1, self._check_if_finished)
+        if self.stream_position() == 1:
+            blob_downloaded = self.download_manager.blobs[0]
+            log.debug("The blob %s has been downloaded. Calling the finished callback", str(blob_downloaded))
+            safe_stop_looping_call(self.checker)
+            self.finished_callback(blob_downloaded)
 
     def stream_position(self):
         blobs = self.download_manager.blobs
@@ -74,15 +64,6 @@ class SingleProgressManager(object):
         assert len(blobs) == 1
         return [b for b in blobs.itervalues() if not b.is_validated()]
 
-    def blob_downloaded(self, blob, blob_num):
-
-        from twisted.internet import reactor
-
-        log.debug("The blob %s has been downloaded. Calling the finished callback", str(blob))
-        if self.finished is False:
-            self.finished = True
-            reactor.callLater(0, self.finished_callback, blob)
-
 
 class DummyBlobHandler(object):
     def __init__(self):
diff --git a/lbrynet/core/utils.py b/lbrynet/core/utils.py
index eeb3f6be7..9dd629d92 100644
--- a/lbrynet/core/utils.py
+++ b/lbrynet/core/utils.py
@@ -49,6 +49,13 @@ def call_later(delay, func, *args, **kwargs):
     from twisted.internet import reactor
     return reactor.callLater(delay, func, *args, **kwargs)
 
+def safe_start_looping_call(looping_call, interval_sec):
+    if not looping_call.running:
+        looping_call.start(interval_sec)
+
+def safe_stop_looping_call(looping_call):
+    if looping_call.running:
+        looping_call.stop()
 
 def generate_id(num=None):
     h = get_lbry_hash_obj()