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-rw-r--r--acf2/transaction/init.lua210
1 files changed, 210 insertions, 0 deletions
diff --git a/acf2/transaction/init.lua b/acf2/transaction/init.lua
new file mode 100644
index 0000000..eb316b5
--- /dev/null
+++ b/acf2/transaction/init.lua
@@ -0,0 +1,210 @@
+--[[
+Copyright (c) 2012-2013 Kaarle Ritvanen
+See LICENSE file for license details
+--]]
+
+local ErrorDict = require('acf2.error').ErrorDict
+local root = require('acf2.model.root')
+local object = require('acf2.object')
+local pth = require('acf2.path')
+local be_mod = require('acf2.transaction.backend')
+
+local util = require('acf2.util')
+local copy = util.copy
+
+
+local function remove_list_value(list, value)
+ value = tostring(value)
+
+ for i, v in ipairs(list) do
+ if tostring(v) == value then
+ table.remove(list, i)
+ return
+ end
+ end
+
+ assert(false)
+end
+
+
+local Transaction = object.class(be_mod.TransactionBackend)
+
+function Transaction:init(backend, validate)
+ object.super(self, Transaction):init()
+
+ self.backend = backend
+
+ self.started = be_mod.gen_number()
+ self.access_time = {}
+
+ self.added = {}
+ self.modified = {}
+ self.deleted = {}
+
+ self.validate = validate
+ self.validable = {}
+
+ self.root = root.RootModel(self)
+end
+
+function Transaction:check()
+ if not self.backend then error('Transaction already committed') end
+end
+
+function Transaction:get(path)
+ self:check()
+
+ if self.deleted[path] then return nil, self.mod_time[path] end
+ for _, tbl in ipairs{self.added, self.modified} do
+ if tbl[path] ~= nil then
+ return copy(tbl[path]), self.mod_time[path]
+ end
+ end
+
+ local value, timestamp = self.backend:get_if_older(path, self.started)
+ self.access_time[path] = timestamp
+ return value, timestamp
+end
+
+function Transaction:_set_multiple(mods)
+
+ local function set(path, value, new)
+ local delete = value == nil
+
+ if self.added[path] == nil and (not new or self.deleted[path]) then
+ self.modified[path] = value
+ self.deleted[path] = delete
+ else self.added[path] = value end
+ end
+
+ for _, mod in ipairs(mods) do
+ local path, value = unpack(mod)
+
+ local ppath = pth.parent(path)
+ local parent = self:get(ppath)
+ if parent == nil then
+ parent = {}
+ self:set(ppath, parent)
+ end
+
+ local name = pth.name(path)
+ local old = self:get(path)
+
+ local is_table = type(value) == 'table'
+ local delete = value == nil
+
+ if delete then
+ -- assume one-level refs for now
+ local top = root.topology(ppath)
+ if top then
+ local errors = ErrorDict()
+ for _, refs in ipairs(top.referrers) do
+ for _, ref in ipairs(self.root:search_refs(refs)) do
+ errors:collect(ref.deleted, ref, path)
+ end
+ end
+ errors:raise()
+ end
+ end
+
+ if type(old) == 'table' then
+ if delete then
+ for _, child in ipairs(old) do self:set(pth.join(path, child)) end
+ elseif is_table then return
+ elseif #old > 0 then
+ error('Cannot assign a primitive value to non-leaf node '..path)
+ end
+ end
+
+ if is_table then value = {} end
+ set(path, value, old == nil)
+
+ local function set_parent()
+ set(ppath, parent)
+ self.mod_time[ppath] = self.mod_time[path]
+ end
+
+ if old == nil and not delete then
+ table.insert(parent, name)
+ set_parent()
+ elseif old ~= nil and delete then
+ remove_list_value(parent, name)
+ set_parent()
+ end
+ end
+end
+
+function Transaction:fetch(path) return self.root:fetch(path) end
+
+function Transaction:meta(path) return self.root:meta(path) end
+
+function Transaction:commit()
+ self:check()
+
+ if self.validate then
+ local errors = ErrorDict()
+ for path, addr in pairs(copy(self.validable)) do
+ if self:get(addr) ~= nil then
+ errors:collect(getmetatable(self:fetch(path)).validate)
+ end
+ end
+ errors:raise()
+ end
+
+ local mods = {}
+ local handled = {}
+
+ local function insert(path, value)
+ assert(not handled[path])
+ table.insert(mods, {path, value})
+ handled[path] = true
+ end
+
+ local function insert_add(path)
+ if not handled[path] then
+ local pp = pth.parent(path)
+ if self.added[pp] then insert_add(pp) end
+ insert(path, self.added[path])
+ end
+ end
+
+ local function insert_del(path)
+ if not handled[path] then
+ local value = self.backend:get(path)
+ if type(value) == 'table' then
+ for _, child in ipairs(value) do
+ local cp = pth.join(path, child)
+ assert(self.deleted[cp])
+ insert_del(cp)
+ end
+ end
+ insert(path)
+ end
+ end
+
+ for path, deleted in pairs(self.deleted) do
+ if deleted then insert_del(path) end
+ end
+
+ for path, value in pairs(self.modified) do
+ if type(value) ~= 'table' then insert(path, value) end
+ end
+
+ for path, _ in pairs(self.added) do insert_add(path) end
+
+ self.backend:comp_and_setm(self.access_time, mods)
+
+
+ if not self.validate then
+ util.update(self.backend.validable, self.validable)
+ end
+
+ self.backend = nil
+end
+
+
+local store = require('acf2.persistence')
+
+return function(txn, defer_validation)
+ return Transaction(txn or store, not (txn and defer_validation))
+ end