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--[[
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
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