Fixes the way threading works

comic_download/comic_strip.py

@@ -5,7 +5,7 @@ import logging.handlers
 import argparse
 from abc import ABC, abstractmethod
 from datetime import datetime
-from threading import Lock
+from threading import Lock, Condition
 import bisect
 import time
 import re
@@ -102,9 +102,9 @@ class ImageRepo(ABC):
 
         self._data_loaded = False
         """A flag for when the data has been successfully loaded."""
-        self._load_lock = Lock()
+        self._load_lock = Condition(Lock())
         """A lock for enforcing thread safety when loading this repository."""
-        self._download_lock = Lock()
+        self._download_lock = Condition(Lock())
         """A lock for enforcing thread safety when downloading secondary resources."""
 
     def get_identifier_string(self):
@@ -122,7 +122,7 @@ class ImageRepo(ABC):
 
         :returns: True if the data has been fully loaded, false otherwise.
         """
-        return not self._load_lock.locked() and self._data_loaded
+        return not self._load_lock._lock.locked() and self._data_loaded
 
     def is_downloaded(self):
         """
@@ -130,7 +130,7 @@ class ImageRepo(ABC):
 
         :returns: True if the images have been fully downloaded, false otherwise.
         """
-        return not self.image_urls or (not self._download_lock.locked() and self.images)
+        return not self.image_urls or (not self._download_lock._lock.locked() and self.images)
         
     def load_data(self):
         """
@@ -147,12 +147,12 @@ class ImageRepo(ABC):
         :see: #await_load
         :see: #_load_data
         """
-        if not self._load_lock.locked() and not self._data_loaded:
-            if self._load_lock.acquire():
+        with self._load_lock:
+            if not self._data_loaded:
                 self._load_data()
                 logging.info("Completed loading of %s", self.get_identifier_string())
                 self._data_loaded = True
-                self._load_lock.release()
+                self._load_lock.notify_all()
 
     def await_load(self):
         """
@@ -162,12 +162,8 @@ class ImageRepo(ABC):
         :see: #load_data
         """
 
-        if self._load_lock.locked():
-            self._load_lock.acquire()
-            self._load_lock.release()
-        else:
-            # Loads this ourselves
-            self.load_data()
+        # Loads this ourselves
+        self.load_data()
         
 
     @abstractmethod
@@ -200,12 +196,13 @@ class ImageRepo(ABC):
         if not self.is_loaded():
             raise SequenceException("Cannot download images before first loading performed.")
 
-        # Checks to see if we need to download and that one is not already in progress
-        if not self._download_lock.locked() and self.image_urls and not self.images:
-            if self._download_lock.acquire():
+        with self._download_lock:
+            # Checks to see if we need to download and that one is not already in progress
+            if self.image_urls and not self.images:
+                logging.info("Downloading %s", self.get_identifier_string())
                 self._download_data()
                 logging.info("Completed downloading of %s", self.get_identifier_string())
-                self._download_lock.release()
+                self._download_lock.notify_all()
 
     def await_download(self):
         """
@@ -215,12 +212,7 @@ class ImageRepo(ABC):
         :see: #download_data
         """
 
-        if self._download_lock.locked():
-            self._download_lock.acquire()
-            self._download_lock.release()
-        else:
-            # Downloads this ourselves
-            self.download_data()
+        self.download_data()
 
     def _download_data(self):
         """
@@ -346,7 +338,7 @@ class ComicStrip(ImageRepo, ABC):
         """A list of captions for each panel."""
         self.date = None
         """The date that the comic was published."""
-        self._transform_lock = Lock()
+        self._transform_lock = Condition(Lock())
         """A lock for enforcing thread safety when transforming resources."""
         self.transformed_images = []
         """A list of NamedTemporaryFiles linking to the transformed versions of the image downloads."""
@@ -438,21 +430,20 @@ class ComicStrip(ImageRepo, ABC):
         if not self.is_downloaded():
             raise SequenceException("Cannot package comic strip before strip data has been fully downloaded.")
         if not self.comic.is_loaded():
-            raise SequenceException("Cannot package comic before data has been fully loaded.")
+            raise SequenceException("Cannot package comic strip before comic data has been fully loaded.")
         if not self.comic.is_downloaded():
-            raise SequenceException("Cannot package comic before data has been fully downloaded.")
+            raise SequenceException("Cannot package comic strip before comic data has been fully downloaded.")
         if not self.transformed_images:
             if not self._transformed:
-                if self._transform_lock.locked():
+                if self._transform_lock._lock.locked():
                     # Await for the existing transform to complete
-                    self._transform_lock.acquire()
-                    self._transform_lock.release()
+                    self._transform_lock.wait()
                 else:
                     # Run the transformation outselves
-                    self._transform_lock.acquire()
-                    self._transform_images()
-                    self._transformed = True
-                    self._transform_lock.release()
+                    with self._transform_lock:
+                        self._transform_images()
+                        self._transformed = True
+                        self._transform_lock.notify_all()
         with ZipFile(self.get_package_path(base_path), 'w') as comic_zip:
             for i in range(len(self.transformed_images)):
                 image = self.transformed_images[i]