refactoring memory and disk cache abstractions

bauh/util/disk.py

@@ -0,0 +1,72 @@
+import json
+import os
+from threading import Thread, Lock
+from typing import Type, Dict
+
+from bauh_api.abstract.cache import MemoryCache
+from bauh_api.abstract.disk import DiskCacheLoader, DiskCacheLoaderFactory
+from bauh_api.abstract.model import SoftwarePackage
+
+
+class AsyncDiskCacheLoader(Thread, DiskCacheLoader):
+
+    def __init__(self, enabled: bool, cache_map: Dict[Type[SoftwarePackage], MemoryCache]):
+        super(AsyncDiskCacheLoader, self).__init__(daemon=True)
+        self.apps = []
+        self.stop = False
+        self.lock = Lock()
+        self.cache_map = cache_map
+        self.enabled = enabled
+
+    def fill(self, pkg: SoftwarePackage):
+        """
+        Adds a package which data must be read from the disk to a queue.
+        :param pkg:
+        :return:
+        """
+        if self.enabled:
+            if pkg and pkg.supports_disk_cache():
+                self.lock.acquire()
+                self.apps.append(pkg)
+                self.lock.release()
+
+    def run(self):
+        if self.enabled:
+            while True:
+                if self.apps:
+                    self.lock.acquire()
+                    app = self.apps[0]
+                    del self.apps[0]
+                    self.lock.release()
+                    self._fill_cached_data(app)
+                elif self.stop:
+                    break
+
+    def _fill_cached_data(self, pkg: SoftwarePackage):
+        if self.enabled:
+            if os.path.exists(pkg.get_disk_data_path()):
+                with open(pkg.get_disk_data_path()) as f:
+                    cached_data = json.loads(f.read())
+                    pkg.fill_cached_data(cached_data)
+                    cache = self.cache_map.get(pkg.__class__)\
+
+                    if cache:
+                        cache.add_non_existing(pkg.base_data.id, cached_data)
+
+
+class DefaultDiskCacheLoaderFactory(DiskCacheLoaderFactory):
+
+    def __init__(self, disk_cache_enabled: bool):
+        super(DefaultDiskCacheLoaderFactory, self).__init__()
+        self.disk_cache_enabled = disk_cache_enabled
+        self.cache_map = {}
+
+    def map(self, pkg_type: Type[SoftwarePackage], cache: MemoryCache):
+        if pkg_type:
+            if pkg_type in self.cache_map:
+                raise Exception('{} is already mapped')
+
+            self.cache_map[pkg_type] = cache
+
+    def new(self) -> AsyncDiskCacheLoader:
+        return AsyncDiskCacheLoader(enabled=self.disk_cache_enabled, cache_map=self.cache_map)