1 files changed, 379 insertions, 0 deletions
diff --git a/aconf/model/node.lua b/aconf/model/node.lua
new file mode 100644
index 0000000..49053f5
--- /dev/null
+++ b/aconf/model/node.lua
@@ -0,0 +1,379 @@
+--[[
+Copyright (c) 2012-2014 Kaarle Ritvanen
+See LICENSE file for license details
+--]]
+
+local M = {}
+
+local raise = require('aconf.error').raise
+
+local object = require('aconf.object')
+local class = object.class
+local isinstance = object.isinstance
+local super = object.super
+
+local pth = require('aconf.path')
+
+local util = require('aconf.util')
+local copy = util.copy
+local update = util.update
+
+
+function M.null_addr(path, name) return '/null'..pth.join(path, name) end
+
+
+M.BoundMember = class()
+
+function M.BoundMember:init(parent, name, field)
+   local pmt = getmetatable(parent)
+   local mt = {}
+
+   function mt.__index(t, k)
+      local member = field[k]
+      if type(member) ~= 'function' then return member end
+
+      local addr = field.addr or pth.escape(name)
+      if type(addr) == 'function' then addr = addr(pmt.path, name) end
+      return function(self, ...)
+		return member(
+		   field,
+		   {
+		      txn=pmt.txn,
+		      parent=parent,
+		      path=pth.join(pmt.path, name),
+		      addr=pth.to_absolute(addr, pmt.addr)
+		   },
+		   ...
+		)
+	     end
+   end
+
+   setmetatable(self, mt)
+end
+
+
+M.TreeNode = class()
+
+local function equal_tns(tn1, tn2)
+   return getmetatable(tn1).path == getmetatable(tn2).path
+end
+
+function M.TreeNode:init(context, dtype, editable)
+   local mt = getmetatable(self)
+   update(mt, context)
+
+   mt.name = pth.name(mt.path)
+   mt.__eq = equal_tns
+
+   function mt.meta()
+      if not mt._meta then
+	 mt._meta = {type=dtype}
+	 if mt.txn then
+	    if mt.parent then
+	       mt._meta['ui-name'] =
+		  getmetatable(mt.parent).mmeta(mt.name)['ui-name']
+	    end
+	    mt.init_meta(mt._meta)
+	 end
+      end
+      return mt._meta
+   end
+
+   function mt.get(k, options) return mt.load(k, options) end
+   function mt.removable() return true end
+
+   function mt.member_removable(k)
+      local v = mt.load(k, {dereference=false})
+      return editable and (
+	    not isinstance(v, M.TreeNode) or getmetatable(v).removable()
+      )
+   end
+
+   function mt.check_removable(k, v)
+      if v == nil and not mt.member_removable(k) then
+	 raise(pth.join(mt.path, k), 'Cannot be deleted')
+      end
+   end
+
+   if not mt.txn then return end
+
+   function mt.save(k, v) rawset(self, k, v) end
+   function mt.__index(t, k) return mt.get(k) end
+   function mt.__newindex(t, k, v) mt.save(k, v) end
+
+   function mt.has_permission(user, permission)
+      local p = permission..mt.path
+      if mt.txn:fetch('/auth/permissions')[p] then
+	 return user:check_permission(p)
+      end
+
+      if ({create=true, delete=true})[permission] then
+	 permission = 'modify'
+      end
+      return M.has_permission(mt.parent, user, permission)
+   end
+
+   mt.txn.validable[mt.path] = mt.addr
+end
+
+function M.TreeNode:fetch(path, create)
+   local mt = getmetatable(self)
+
+   if type(path) == 'string' then
+      if pth.is_absolute(path) and mt.path > '/' then
+	 assert(not create)
+	 return mt.txn:fetch(path)
+      end
+      path = pth.split(path)
+   end
+
+   if #path == 0 then return self end
+
+   local name = path[1]
+   table.remove(path, 1)
+
+   if name == pth.up then
+      if not mt.parent then
+	 raise(mt.path, 'Root object does not have parent')
+      end
+      return M.TreeNode.fetch(mt.parent, path, create)
+   end
+
+   if not mt.member(name) then
+      raise(mt.path, 'Member does not exist: '..name)
+   end
+
+   local options = {}
+   if create then
+      options.create = true
+      if #path == 0 then options.dereference = false end
+   end
+   local next = mt.get(name, options)
+   if next == nil and (not create or #path > 0) then
+      raise(mt.path, 'Subordinate does not exist: '..name)
+   end
+
+   if #path > 0 and type(next) ~= 'table' then
+      raise(pth.join(mt.path, name), 'Is a primitive value')
+   end
+
+   return M.TreeNode.fetch(next, path, create)
+end
+
+function M.TreeNode:search_refs(path)
+   if type(path) == 'string' then path = pth.split(path) end
+
+   if #path == 0 then return {} end
+
+   local mt = getmetatable(self)
+   local name = path[1]
+   table.remove(path, 1)
+
+   local function collect(name)
+      local next = mt.load(name, {dereference=false})
+      if not next then return {} end
+      
+      local member = mt.member(name)
+      if member.deleted then return {member} end
+      
+      return isinstance(next, M.TreeNode) and M.TreeNode.search_refs(
+	 next, path
+      ) or {}
+   end
+
+   if name == pth.wildcard then
+      local res = {}
+      for _, member in ipairs(mt.members()) do
+	 util.extend(res, collect(member))
+      end
+      return res
+   end
+
+   return collect(name)
+end
+
+
+M.Collection = class(M.TreeNode)
+
+function M.Collection:init(context, params, dtype)
+   super(self, M.Collection):init(
+      context, dtype or 'collection', params.editable
+   )
+
+   self.init = nil
+   self.fetch = nil
+   self.search_refs = nil
+
+   local mt = getmetatable(self)
+   local field = M.BoundMember(self, pth.wildcard, params.field)
+
+   function mt.topology() return field:topology() end
+
+   function mt.member(name)
+      return M.BoundMember(self, name, params.field)
+   end
+
+   function mt.load(k, options) return mt.member(k):load(options) end
+
+   if not mt.txn then return end
+
+   function mt.init_meta(meta)
+      update(
+	 meta,
+	 {
+	    editable=params.editable,
+	    members=field:meta(),
+	    required=params.required,
+	    ['ui-member']=params.ui_member or meta['ui-name']:gsub('s$', ''),
+	    widget=params.layout
+	 }
+      )
+   end
+
+   local meta = mt.meta
+   function mt.meta()
+      local res = copy(meta())
+      res.removable = {}
+      for _, member in ipairs(mt.members()) do
+	 if mt.member_removable(member) then
+	    table.insert(res.removable, member)
+	 end
+      end
+      return res
+   end
+
+   function mt.mmeta(name)
+      local meta = mt.meta()
+      local res = copy(meta.members)
+      if name ~= pth.wildcard then
+	 res['ui-name'] = meta['ui-member']..' '..name
+      end
+      return res
+   end
+
+   function mt.members() return mt.txn:get(mt.addr) or {} end
+
+   function mt.__len() return #mt.members() end
+
+   function mt.validate()
+      if #mt.members() > 0 then return end
+      if params.required then raise(mt.path, 'Collection cannot be empty') end
+      if params.destroy then
+	 mt.txn:set(mt.addr)
+	 validate(mt.parent)
+      end
+   end
+   
+   function mt.save(k, v)
+      if not params.editable then
+	 raise(mt.path, 'Collection is not editable')
+      end
+
+      mt.check_removable(k, v)
+
+      if params.key then
+	 local kf = M.BoundMember(self, k, params.key)
+	 if kf:normalize(k) ~= k then
+	    raise(mt.path, 'Invalid member name: '..k)
+	 end
+	 kf:validate(k)
+      end
+
+      mt.member(k):save(v)
+   end
+end
+
+
+M.List = class(M.Collection)
+
+function M.List:init(context, params, dtype)
+   super(self, M.List):init(context, params, dtype or 'list')
+
+   local mt = getmetatable(self)
+
+   local save = mt.save
+   function mt.save(k, v)
+      assert(type(k) == 'number')
+      if v == nil then
+	 local len = #mt.members()
+	 while k < len do
+	    mt.save(k, mt.load(k + 1, {dereference=false}))
+	    k = k + 1
+	 end
+      end
+      save(k, v)
+   end
+
+   function mt.insert(v, i)
+      local len = #mt.members()
+      if not i then i = len + 1 end
+      for j = len,i,-1 do mt.save(j + 1, mt.load(j, {dereference=false})) end
+      mt.save(i, v)
+   end
+end
+
+
+-- experimental
+M.Mixed = class(M.Collection)
+
+function M.Mixed:init(context, params)
+   super(self, M.Mixed):init(context, params)
+
+   -- TODO dynamic meta: list non-leaf children
+   local mt = getmetatable(self)
+   mt.meta = {type='mixed', ['ui-name']=mt.path}
+   function mt.mmeta(name)
+      return {type='mixed', ['ui-name']=pth.join(mt.path, name)}
+   end
+end
+
+
+local function meta_func(attr)
+   return function(node, ...)
+	     local res = getmetatable(node)[attr]
+	     if type(res) == 'function' then return res(...) end
+	     return res
+	  end
+end
+
+for _, mf in ipairs{
+   'addr',
+   'contains',
+   'has_permission',
+   'insert',
+   'match',
+   'meta',
+   'mmeta',
+   'name',
+   'parent',
+   'path',
+   'save',
+   'topology'
+} do M[mf] = meta_func(mf) end
+
+
+function M.pairs(tbl, dereference)
+   if not isinstance(tbl, M.TreeNode) then return pairs(tbl) end
+
+   local mt = getmetatable(tbl)
+
+   local res = {}
+   for _, member in ipairs(mt.members()) do
+      res[member] = mt.load(member, {dereference=dereference})
+   end
+   return pairs(res)
+end
+
+local function _ipairs(mt, i)
+   i = i + 1
+   local v = mt.load(i, {create=false})
+   if v == nil then return end
+   return i, v
+end
+function M.ipairs(tbl)
+   if not isinstance(tbl, M.TreeNode) then return ipairs(tbl) end
+   return _ipairs, getmetatable(tbl), 0
+end
+
+
+return M