improved handling of nested transactions

add nested transaction support to protocol
allow deferring validation to parent transaction
process each update request within a nested transaction

1 files changed, 11 insertions, 8 deletions

diff --git a/acf/model/node.lua b/acf/model/node.lua
index 3459fce..f893d6a 100644
--- a/acf/model/node.lua
+++ b/acf/model/node.lua
@@ -48,6 +48,8 @@ function TreeNode:init(txn, path, addr)
    mt.txn = txn
    mt.path = path
    mt.addr = addr
+
+   txn.validable[path] = true
 end
 
 function TreeNode:search(path)
@@ -67,14 +69,6 @@ Collection = class(TreeNode)
 function Collection:init(txn, path, addr, field, required)
    super(self, Collection):init(txn, path, addr)
 
-   if required then
-      txn.validate[path] = function()
-			      if #txn:get(addr) == 0 then
-				 raise(path, 'Collection cannot be empty')
-			      end
-			   end
-   end
-
    self.init = nil
    self.search = nil
 
@@ -84,6 +78,14 @@ function Collection:init(txn, path, addr, field, required)
    mt.meta = {type='collection', members=mt.field:meta('$')}
    function mt.mmeta(name) return mt.meta.members end
    function mt.members() return txn:get(addr) or {} end
+
+   function mt.validate()
+      if required then
+	 if #txn:get(addr) == 0 then
+	    raise(path, 'Collection cannot be empty')
+	 end
+      end
+   end
    
    function mt.__index(t, k) return mt.field:load(k) end
    function mt.__newindex(t, k, v) mt.field:save(k, v) end
@@ -132,3 +134,4 @@ members = meta_func('members')
 meta = meta_func('meta')
 mmeta = meta_func('mmeta')
 path = meta_func('path')
+validate = meta_func('validate')