From 426f4db75b7454422ce0131e104cf6e7fd90b1ce Mon Sep 17 00:00:00 2001
From: Laurent Bachelier <laurent@bachelier.name>
Date: Fri, 6 Oct 2017 16:41:15 +0200
Subject: [PATCH] config: Add extra classes

---
 weboob/tools/config/extra.py | 88 ++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 weboob/tools/config/extra.py

diff --git a/weboob/tools/config/extra.py b/weboob/tools/config/extra.py
new file mode 100644
index 0000000000..56d9a49c55
--- /dev/null
+++ b/weboob/tools/config/extra.py
@@ -0,0 +1,88 @@
+import multiprocessing
+import os
+from datetime import datetime
+
+
+__all__ = ['AutoCleanConfig', 'ForkingConfig', 'TimeBufferConfig']
+
+
+"""
+These classes add functionality to existing IConfig classes.
+Example:
+
+    class MyYamlConfig(TimeBufferConfig, ForkingConfig, YamlConfig):
+        saved_since_seconds = 42
+
+The recommended order is TimeBufferConfig, AutoCleanConfig, ForkingConfig, and then the
+actual storage class.
+"""
+
+
+class AutoCleanConfig(object):
+    """
+    Removes config file if it has no values.
+    """
+    def save(self):
+        if self.values:
+            super(AutoCleanConfig, self).save()
+        elif os.path.exists(self.path):
+            os.remove(self.path)
+
+
+class ForkingConfig(object):
+    """
+    Runs the actual save in a forked processes, making save non-blocking.
+    It prevents two save() from being called at once by blocking on the previous one
+    if it is not finished.
+    It is also possible to call join() to wait for the save to complete.
+    """
+    process = None
+
+    def join(self):
+        if self.process:
+            self.process.join()
+
+    def save(self):
+        # if a save is already in progress, wait for it to finish
+        self.join()
+
+        parent_save = super(ForkingConfig, self).save
+        self.process = multiprocessing.Process(target=parent_save, name=u'save %s' % self.path)
+        self.process.start()
+
+    def __exit__(self, t, v, tb):
+        self.join()
+        super(ForkingConfig, self).__exit__(t, v, tb)
+
+
+class TimeBufferConfig(object):
+    """
+    Really saves only every saved_since_seconds seconds.
+    It is possible to force save (e.g. at exit) with force_save().
+    """
+    last_save = None
+    saved_since_seconds = None
+
+    def __init__(self, path, saved_since_seconds=None):
+        super(TimeBufferConfig, self).__init__(path)
+        self.saved_since_seconds = saved_since_seconds
+
+    def load(self, default={}):
+        super(TimeBufferConfig, self).load(default)
+        self.last_save = datetime.now()
+
+    def save(self, saved_since_seconds=None):
+        if saved_since_seconds is None:
+            saved_since_seconds = self.saved_since_seconds
+        if saved_since_seconds and self.last_save:
+            if (datetime.now() - self.last_save).seconds < saved_since_seconds:
+                return
+        super(TimeBufferConfig, self).save()
+        self.last_save = datetime.now()
+
+    def force_save(self):
+        self.save(False)
+
+    def __exit__(self, t, v, tb):
+        self.force_save()
+        super(TimeBufferConfig, self).__exit__(t, v, tb)
-- 
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