deferred final commit for configurable backend addresses

1 files changed, 47 insertions, 0 deletions

diff --git a/acf2/persistence/defer.lua b/acf2/persistence/defer.lua
new file mode 100644
index 0000000..e93f49e
--- /dev/null
+++ b/acf2/persistence/defer.lua
@@ -0,0 +1,47 @@
+--[[
+Copyright (c) 2012-2014 Kaarle Ritvanen
+See LICENSE file for license details
+--]]
+
+local object = require('acf2.object')
+local super = object.super
+
+local pth = require('acf2.path')
+
+
+local DeferringCommitter = object.class(
+   require('acf2.transaction.base').Transaction
+)
+
+function DeferringCommitter:init(backend)
+   super(self, DeferringCommitter):init(backend)
+   self.defer_paths = {}
+   self.committed = true
+end
+
+function DeferringCommitter:defer(path) self.defer_paths[path] = true end
+
+function DeferringCommitter:_set_multiple(mods)
+   super(self, DeferringCommitter):_set_multiple(mods)
+
+   if not self.committed then return end
+   self.committed = false
+
+   for _, mod in ipairs(mods) do
+      local path, value = unpack(mod)
+      while path > '/' do
+	 if self.defer_paths[path] then return end
+	 path = pth.parent(path)
+      end
+   end
+
+   self:commit()
+end
+
+function DeferringCommitter:commit()
+   super(self, DeferringCommitter):commit()
+   self.committed = true
+end
+
+
+return DeferringCommitter(require('acf2.persistence'))