From b5e5e75337b415218496552834b66f5953d7b3d6 Mon Sep 17 00:00:00 2001
From: Aleksey Lim <alsroot@sugarlabs.org>
Date: Sun, 01 Sep 2013 15:21:36 +0000
Subject: Limit disk cache with percents and exact size

---
diff --git a/sugar-network b/sugar-network
index 5276eae..8f07434 100755
--- a/sugar-network
+++ b/sugar-network
@@ -362,10 +362,9 @@ toolkit.cachedir.value = client.profile_path('tmp')
 Option.seek('main', [
     application.debug, porcelain, post_data, post_file, json, offline,
     ])
-Option.seek('client', [
-    client.api_url, client.layers, client.ipc_port, client.local_root,
-    client.no_dbus, client.anonymous, client.accept_language,
-    ])
+Option.seek('main', [toolkit.cachedir])
+Option.seek('client', client)
+Option.seek('db', db)
 
 locale.setlocale(locale.LC_ALL, '')
 
diff --git a/sugar_network/client/__init__.py b/sugar_network/client/__init__.py
index 077027a..d9e68fd 100644
--- a/sugar_network/client/__init__.py
+++ b/sugar_network/client/__init__.py
@@ -120,10 +120,17 @@ accept_language = Option(
         name='accept-language', short_option='-l')
 
 cache_limit = Option(
-        'the minimal disk free space, in percents, to preserve '
-        'while recycling disk cache',
+        'the minimal disk free space, in bytes, to preserve while recycling '
+        'disk cache; the final limit will be a minimal between --cache-limit '
+        'and --cache-limit-percent',
         default=10, type_cast=int, name='cache-limit')
 
+cache_limit_percent = Option(
+        'the minimal disk free space, in percentage terms, to preserve while '
+        'recycling disk cache; the final limit will be a minimal between '
+        '--cache-limit and --cache-limit-percent',
+        default=1024 * 1024 * 10, type_cast=int, name='cache-limit-percent')
+
 cache_lifetime = Option(
         'the number of days to keep unused objects on disk cache '
         'before recycling',
diff --git a/sugar_network/client/cache.py b/sugar_network/client/cache.py
index 3043d25..685bdf4 100644
--- a/sugar_network/client/cache.py
+++ b/sugar_network/client/cache.py
@@ -41,22 +41,10 @@ class Cache(object):
 
     def ensure(self, requested_size, temp_size=0):
         self._ensure_open()
-        stat = os.statvfs(client.local_root.value)
-        if stat.f_blocks == 0:
-            # TODO Sonds like a tmpfs or so
-            return
-        total = stat.f_blocks * stat.f_frsize
-        free = stat.f_bfree * stat.f_frsize
-
-        to_free = max(client.cache_limit.value * total / 100, temp_size) - \
-                (free - requested_size)
+        to_free = self._to_free(requested_size, temp_size)
         if to_free <= 0:
             return
-
-        _logger.debug('Recycle %s byte free=%d requested_size=%d temp_size=%d',
-                to_free, free, requested_size, temp_size)
         enforce(self._du >= to_free, 'No free disk space')
-
         for guid, size, mtime in self._reversed_iter():
             self._checkout(guid, (size, mtime))
             to_free -= size
@@ -86,12 +74,8 @@ class Cache(object):
 
     def recycle(self):
         self._ensure_open()
-        stat = os.statvfs(client.local_root.value)
-        total = stat.f_blocks * stat.f_frsize
-        free = stat.f_bfree * stat.f_frsize
-        to_free = client.cache_limit.value * total / 100 - free
         ts = time.time()
-
+        to_free = self._to_free(0, 0)
         for guid, size, mtime in self._reversed_iter():
             if to_free > 0:
                 self._checkout(guid, (size, mtime))
@@ -131,6 +115,32 @@ class Cache(object):
             self._pool[guid] = (size, mtime)
             self._du += size
 
+    def _to_free(self, requested_size, temp_size):
+        if not client.cache_limit.value and \
+                not client.cache_limit_percent.value:
+            return 0
+
+        stat = os.statvfs(client.local_root.value)
+        if stat.f_blocks == 0:
+            # TODO Sonds like a tmpfs or so
+            return 0
+
+        limit = 0
+        free = stat.f_bfree * stat.f_frsize
+        if client.cache_limit_percent.value:
+            total = stat.f_blocks * stat.f_frsize
+            limit = client.cache_limit_percent.value * total / 100
+        if client.cache_limit.value:
+            limit = min(limit, client.cache_limit.value)
+        to_free = max(limit, temp_size) - (free - requested_size)
+
+        if to_free > 0:
+            _logger.debug(
+                    'Need to recycle %d bytes, '
+                    'free_size=%d requested_size=%d temp_size=%d',
+                    to_free, free, requested_size, temp_size)
+        return to_free
+
     def _reversed_iter(self):
         i = self._pool.head.prev
         while True:
diff --git a/tests/units/client/cache.py b/tests/units/client/cache.py
index 871e62c..af05f43 100755
--- a/tests/units/client/cache.py
+++ b/tests/units/client/cache.py
@@ -13,7 +13,7 @@ from __init__ import tests
 from sugar_network import db
 from sugar_network.model.context import Context
 from sugar_network.model.implementation import Implementation
-from sugar_network.client import cache_limit, cache_lifetime, IPCConnection
+from sugar_network.client import cache_limit, cache_limit_percent, cache_lifetime, IPCConnection
 from sugar_network.client.cache import Cache
 from sugar_network.toolkit import http
 
@@ -31,6 +31,7 @@ class CacheTest(tests.Test):
         self.statvfs = statvfs
         self.override(os, 'statvfs', lambda *args: statvfs())
         cache_limit.value = 0
+        cache_limit_percent.value = 0
 
     def test_open(self):
         volume = db.Volume('db', [Context, Implementation])
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