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--[[
Copyright (c) 2012-2013 Kaarle Ritvanen
See LICENSE file for license details
--]]
module(..., package.seeall)
local ErrorDict = require('acf.error').ErrorDict
local RootModel = require('acf.model').RootModel
local object = require('acf.object')
local super = object.super
local pth = require('acf.path')
local be_mod = require('acf.transaction.backend')
local copy = require('acf.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)
super(self, Transaction):init()
self.backend = backend
self.started = be_mod.gen_number()
self.access_time = {}
self.added = {}
self.modified = {}
self.deleted = {}
self.validate = {}
self.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][2]), 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)
super(self, Transaction):set_multiple(mods)
local function set(path, t, value, new)
local delete = value == nil
value = not delete and {t, value} or 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, t, value = unpack(mod)
local ppath = pth.parent(path)
local parent = self:get(ppath)
if parent == nil then
self:set(ppath, 'table', true)
parent = {}
end
local name = pth.name(path)
local old = self:get(path)
local is_table = t == 'table'
local delete = not is_table and value == nil
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, not delete and t or nil, value, old == nil)
if old == nil and not delete then
table.insert(parent, name)
set(ppath, 'table', parent)
elseif old ~= nil and delete then
remove_list_value(parent, name)
set(ppath, 'table', parent)
end
end
end
function Transaction:search(path) return self.root:search(pth.split(path)) end
function Transaction:commit()
self:check()
local errors = ErrorDict()
for path, func in pairs(self.validate) do
if not self.deleted[path] then errors:collect(func) end
end
errors:raise()
local mods = {}
local handled = {}
local function insert(path, t, value)
assert(not handled[path])
table.insert(mods, {path, t, 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
local t, value = unpack(self.added[path])
if t == 'table' then value = nil end
insert(path, t, value)
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
local t, v = unpack(value)
if t ~= 'table' then insert(path, t, v) end
end
for path, _ in pairs(self.added) do insert_add(path) end
self.backend:comp_and_setm(self.access_time, mods)
self.backend = nil
end
local store = require('acf.persistence').DataStore()
function start(txn) return Transaction(txn or store) end
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