GC support

1. Removed threading & new test
2. Improved time complexity.
3. Minor fixes.

Author: amsukdu

ring/func/base.py

@@ -562,6 +562,7 @@ def factory(
         # keyword-only arguments from here
         # building blocks
         coder, miss_value, user_interface, storage_class,
+        maxsize=128,
         default_action=Ellipsis,
         coder_registry=Ellipsis,
         # callback
@@ -638,7 +639,7 @@ class RingRope(RopeCore):
             def __init__(self, *args, **kwargs):
                 super(RingRope, self).__init__(*args, **kwargs)
                 self.user_interface = self.user_interface_class(self)
-                self.storage = self.storage_class(self, storage_backend)
+                self.storage = self.storage_class(self, storage_backend, maxsize)
                 _ignorable_keys = suggest_ignorable_keys(
                     self.callable, ignorable_keys)
                 _key_prefix = suggest_key_prefix(self.callable, key_prefix)
@@ -747,9 +748,10 @@ class BaseStorage(object):
     are mandatory; Otherwise not.
     """
 
-    def __init__(self, rope, backend):
+    def __init__(self, rope, backend, maxsize):
         self.rope = rope
         self.backend = backend
+        self.maxsize = maxsize
 
     @abc.abstractmethod
     def get(self, key):  # pragma: no cover

ring/func/sync.py

@@ -8,7 +8,6 @@
 import time
 import re
 import hashlib
-import threading, random, time
 
 from . import base as fbase, lru_cache as lru_mod
 
@@ -206,82 +205,68 @@ def touch_value(self, key, expire):
         except KeyError:
             pass
 
-class Gc(object):
+class SizeMaintainer(object):
+    _DEBUG = False
 
     def __init__(self, backend, target_size, expire_f=None):
+        from collections import abc
         assert round(target_size) > 0, 'target_size has to be at least 1'
         assert expire_f is None or callable(expire_f), 'expire_f has to be function or None'
-        assert isinstance(backend, type({})), 'backend has to be dict-like'
+        assert isinstance(backend, abc.MutableMapping), 'backend has to be dict-like'
         self._backend = backend
         self._target_size = round(target_size)
         self._expire_f = expire_f
-        self._mutex = threading.Lock()
 
     def run(self):
-        class WorkThread(threading.Thread):
-            DEBUG = False
-
-            def __init__(self, outer_instance):
-                threading.Thread.__init__(self)
-                self._backend = outer_instance._backend
-                self._target_size = outer_instance._target_size
-                self._expire_f = outer_instance._expire_f
-                self._mutex = outer_instance._mutex
-
-            def strategy_with_expire(self):
-                MAX_EXPIRE_RETRY_COUNT = 4
-                now = time.time()
-                retry_count = 0
-                keys = list(self._backend.keys())
-                while (len(self._backend) > self._target_size) and (retry_count < MAX_EXPIRE_RETRY_COUNT):
-                    k = keys.pop(random.randrange(len(keys)))
-                    val = self._backend.get(k, None)
-                    if val is None:
-                        continue
-                    expire = self._expire_f(val)
-                    if expire < now:
-                        self._backend.pop(k, None)
-                        self.print_d('{} removed from strategy_with_expire => size {}'.format(k, len(self._backend)))
-                    else:
-                        retry_count += 1
-                    if len(keys) == 0:
-                        keys = list(self._backend.keys())
-
-            def strategy_with_force(self):
-                keys = list(self._backend.keys())
-                while (len(self._backend) > self._target_size) and len(keys) > 0:
-                    k = keys.pop(random.randrange(len(keys)))
-                    self._backend.pop(k, None)
-                    self.print_d('{} removed from strategy_with_force => size {}'.format(k, len(self._backend)))
-                    if len(keys) == 0:
-                        keys = list(self._backend.keys())
-
-            def run(self):
-                try:
-                    self.print_d('gc started in size:{}'.format(len(self._backend)))
-                    if self._expire_f is not None:
-                        self.strategy_with_expire()
-                    self.strategy_with_force()
-                    self.print_d('gc ended in size:{}'.format(len(self._backend)))
-                finally:
-                    self._mutex.release()
-
-
-            def print_d(self, str_):
-                if self.DEBUG:
-                    print(str_)
-
-        self._mutex.acquire()
-        if (len(self._backend) > self._target_size):
-            WorkThread(self).start()
-        else:
-            self._mutex.release()
+        if (len(self._backend) <= self._target_size):
+            return
+
+        import random, time
+        def strategy_with_expire():
+            MAX_EXPIRE_RETRY_COUNT = 4
+            now = time.time()
+            retry_count = 0
+
+            keys = list(self._backend.keys())
+            random.shuffle(keys)
+            key_index = 0
+            while (len(self._backend) > self._target_size) and (retry_count < MAX_EXPIRE_RETRY_COUNT):
+                key = keys[key_index]
+                val = self._backend.get(key, None)
+                expire = self._expire_f(val)
+                if expire < now:
+                    self._backend.pop(key, None)
+                    key_index += 1
+                    if self._DEBUG:
+                        print('{} removed from strategy_with_expire => size {}'.format(key, len(self._backend)))
+                else:
+                    retry_count += 1
+
+        def strategy_with_force():
+            keys = list(self._backend.keys())
+            random.shuffle(keys)
+            key_index = 0
+            while (len(self._backend) > self._target_size):
+                key = keys[key_index]
+                self._backend.pop(key, None)
+                key_index += 1
+                if self._DEBUG:
+                    print('{} removed from strategy_with_force => size {}'.format(key, len(self._backend)))
+
+        if self._DEBUG:
+            print('gc started in size:{}'.format(len(self._backend)))
+
+        if self._expire_f is not None:
+            strategy_with_expire()
+        strategy_with_force()
+
+        if self._DEBUG:
+            print('gc ended in size:{}'.format(len(self._backend)))
+
 
 class ExpirableDictStorage(fbase.CommonMixinStorage, fbase.StorageMixin):
-    maxsize = 128
     in_memory_storage = True
     now = time.time
-    _gc = None
 
     def get_value(self, key):
         _now = self.now()
@@ -302,9 +287,7 @@ def set_value(self, key, value, expire):
         self.backend[key] = expired_time, value
 
         if self.maxsize < len(self.backend):
-            if self._gc == None:
-                self._gc = Gc(self.backend, self.maxsize * 0.75, lambda x: x[0])
-            self._gc.run()
+            SizeMaintainer(self.backend, self.maxsize * 0.75, lambda x: x[0]).run()
 
     def delete_value(self, key):
         try:
@@ -330,8 +313,6 @@ def touch_value(self, key, expire):
 
 class PersistentDictStorage(fbase.CommonMixinStorage, fbase.StorageMixin):
     in_memory_storage = True
-    maxsize = 128
-    _gc = None
 
     def get_value(self, key):
         try:
@@ -343,9 +324,7 @@ def get_value(self, key):
     def set_value(self, key, value, expire):
         self.backend[key] = value
         if self.maxsize < len(self.backend):
-            if self._gc == None:
-                self._gc = Gc(self.backend, self.maxsize * 0.75)
-            self._gc.run()
+            SizeMaintainer(self.backend, self.maxsize * 0.75).run()
 
     def delete_value(self, key):
         try:
@@ -549,11 +528,10 @@ def dict(
             storage_class = PersistentDictStorage
         else:
             storage_class = ExpirableDictStorage
-        storage_class.maxsize = maxsize
 
     return fbase.factory(
         obj, key_prefix=key_prefix, on_manufactured=None,
-        user_interface=user_interface, storage_class=storage_class,
+        user_interface=user_interface, storage_class=storage_class, maxsize=maxsize,
         miss_value=None, expire_default=expire, coder=coder,
         **kwargs)