Download PMS xml chunks asynchronously

resources/lib/plex_functions.py

@@ -11,9 +11,7 @@ from threading import Thread
 from xbmc import sleep
 
 from .downloadutils import DownloadUtils as DU
-from . import utils
+from . import backgroundthread, utils, plex_tv, variables as v
-from . import plex_tv
-from . import variables as v
 
 ###############################################################################
 LOG = getLogger('PLEX.plex_functions')
@@ -528,6 +526,26 @@ def GetPlexSectionResults(viewId, args=None):
     return DownloadChunks(url)
 
 
+class DownloadChunk(backgroundthread.Task):
+    """
+    This task will also be executed while library sync is suspended!
+    """
+    def setup(self, url, args, callback):
+        self.url = url
+        self.args = args
+        self.callback = callback
+
+    def run(self):
+        xml = DU().downloadUrl(self.url, parameters=self.args)
+        try:
+            xml.attrib
+        except AttributeError:
+            LOG.error('Error while downloading chunks: %s, args: %s',
+                      self.url, self.args)
+            xml = None
+        self.callback(xml)
+
+
 class DownloadGen(object):
     """
     Special iterator object that will yield all child xmls piece-wise. It also
@@ -537,6 +555,8 @@ class DownloadGen(object):
     """
     def __init__(self, url, plex_type=None, last_viewed_at=None,
                  updated_at=None, args=None):
+        self.lock = backgroundthread.threading.Lock()
+        self.pending_lock = backgroundthread.threading.Lock()
         self._args = args or {}
         url += '?'
         if plex_type:
@@ -545,11 +565,13 @@ class DownloadGen(object):
             url = '%slastViewedAt>=%s&' % (url, last_viewed_at)
         if updated_at:
             url = '%supdatedAt>=%s&' % (url, updated_at)
-        if url.endswith('?') or url.endswith('&'):
+        self._url = url[:-1]
-            url = url[:-1]
-        self._url = url
         self._pos = 0
+        self._current = 0
         self._exhausted = False
+        # Start download the next chunk once we've reached 10% of the current
+        # xml's content
+        self._threshold = int(CONTAINERSIZE / 10)
         self._download_chunk()
         self.attrib = deepcopy(self.xml.attrib)
 
@@ -560,6 +582,7 @@ class DownloadGen(object):
             'sort': 'id',  # Entries are sorted by plex_id
             'excludeAllLeaves': 1  # PMS wont attach a first summary child
         })
+        if self._pos == 0:
             self.xml = DU().downloadUrl(self._url, parameters=self._args)
             try:
                 self.xml.attrib
@@ -568,6 +591,22 @@ class DownloadGen(object):
                           self._url, self._args)
                 raise RuntimeError('Error while downloading chunks for %s'
                                    % self._url)
+            if len(self.xml) < CONTAINERSIZE:
+                self._exhausted = True
+        else:
+            self.pending_lock.acquire()
+            task = DownloadChunk()
+            task.setup(self._url, self._args, self.on_chunk_downloaded)
+            backgroundthread.BGThreader.addTask(task)
+
+    def on_chunk_downloaded(self, xml):
+        if xml:
+            if len(xml) < CONTAINERSIZE:
+                self._exhausted = True
+            with self.lock:
+                for child in xml:
+                    self.xml.append(child)
+        self.pending_lock.release()
 
     def __iter__(self):
         return self
@@ -576,20 +615,25 @@ class DownloadGen(object):
         return self.__next__()
 
     def __next__(self):
-        if len(self.xml):
+        if (not self._exhausted and
-            child = self.xml[0]
+                self._current % CONTAINERSIZE == self._threshold):
-            self.xml.remove(child)
+            # Kick off download of next chunk
-            return child
-        elif self._exhausted:
-            raise StopIteration
-        else:
             self._pos += CONTAINERSIZE
             self._download_chunk()
+        while True:
+            if len(self.xml):
+                child = self.xml[0]
+                with self.lock:
+                    self.xml.remove(child)
+                self._current += 1
+                return child
+            # Currently no items left, BUT some could still be downloading
+            self.pending_lock.acquire()
+            # Above will block until download finished - release immediately
+            # again
+            self.pending_lock.release()
             if not len(self.xml):
                 raise StopIteration
-            if len(self.xml) < CONTAINERSIZE:
-                self._exhausted = True
-            return self.__next__()
 
     def get(self, key, default=None):
         return self.attrib.get(key, default)