persistence: Augeas back-end rewritten

map identically named nodes to collections
implement set function

4 files changed, 118 insertions, 19 deletions

diff --git a/acf/modules/generic.lua b/acf/modules/generic.lua
index 9ec95bf..c8abb9b 100644
--- a/acf/modules/generic.lua
+++ b/acf/modules/generic.lua
@@ -12,5 +12,5 @@ local M = require('acf.model')
 M.register('proc', M.Mixed, '/files/proc')
 M.permission.defaults('/proc')
 
-M.register('augeas', M.Mixed, '/augeas/files')
+M.register('augeas', M.Mixed, '/augeas')
 M.permission.defaults('/augeas')
diff --git a/acf/persistence/backends/augeas.lua b/acf/persistence/backends/augeas.lua
index d3fff0f..e25a568 100644
--- a/acf/persistence/backends/augeas.lua
+++ b/acf/persistence/backends/augeas.lua
@@ -6,21 +6,121 @@ See LICENSE file for license details
 module(..., package.seeall)
 
 local pth = require('acf.path')
-local map = require('acf.util').map
+
+local util = require('acf.util')
+local copy = util.copy
+
+
+local function aug_path(path) return pth.join('/files', unpack(path)) end
+
+local function strip_name(name)
+   return type(name) == 'string' and string.match(name, '^[^][/=)%s]+') or name
+end
+
+local function ipath(path, index) return path..'['..index..']' end
+
 
 backend = require('acf.object').class()
 
 function backend:init() self.aug = require('augeas').init() end
 
+function backend:find(path, tpe)
+   util.map(
+      function(comp)
+	 return comp == strip_name(comp) and not string.match(comp, '^%.+$')
+      end,
+      path
+   )
+   local res = aug_path(path)
+
+   if #self.aug:match(res) == 0 and #path > 1 and tpe ~= 'table' then
+      local index = path[#path]
+      if type(index) == 'number' then
+	 local ppath = copy(path)
+	 table.remove(ppath)
+	 ppath = aug_path(ppath)
+
+	 if #self.aug:match(ppath) > 0 and #self.aug:match(
+	    ppath..'/*'
+	 ) == 0 then
+	    return ipath(ppath, index), ppath, index
+	 end
+      end
+   end
+
+   return res
+end
+
 function backend:get(path, tpe)
-   path = pth.join('/', unpack(path))
-   local _, count = self.aug:match(path)
-   if count == 0 then return end
+   local leaf = tpe and tpe ~= 'table'
+   local apath, mvpath = self:find(path, tpe)
 
-   local value = self.aug:get(path)
-   if value ~= nil then return value end
+   local matches = self.aug:match(apath)
+   if mvpath then
+      assert(#matches < 2)
+      leaf = true
+   end
 
-   return map(pth.name, self.aug:match(path..'/*'))
+   if #matches == 0 then return end
+
+   if #matches > 1 then
+      assert(not leaf)
+      local res = {}
+      path = copy(path)
+      for i, _ in ipairs(matches) do
+	 table.insert(path, i)
+	 if self:get(path) then table.insert(res, i) end
+	 table.remove(path)
+      end
+      return res
+   end
+
+   local value = self.aug:get(matches[1])
+   if value then return tpe == 'table' and {1} or value end
+   if leaf then return end
+
+   local names = {}
+   for _, child in ipairs(self.aug:match(apath..'/*')) do
+      names[strip_name(pth.name(child))] = true
+   end
+   return util.keys(names)
 end
 
--- TODO implement set function
+function backend:set(mods)
+   local gcpaths = {}
+
+   for _, mod in ipairs(mods) do
+      local path, tpe, value = unpack(mod)
+
+      self.aug:rm(aug_path(path)..(tpe and '/*' or ''))
+
+      local apath, mvpath, index = self:find(path, tpe)
+
+      if tpe and mvpath then
+	 local size = #self.aug:match(mvpath)
+	 while size < index do
+	    self.aug:insert(ipath(mvpath, size), pth.name(mvpath))
+	    size = size + 1
+	 end
+      end
+
+      if tpe or mvpath then self.aug:set(apath, value)
+      elseif apath > '/' then apath = pth.parent(apath) end
+
+      if value == nil or value == '' then gcpaths[mvpath or apath] = true end
+   end
+
+   local function gc(path)
+      if path == '/' or #self.aug:match(path..'/*') > 0 then return end
+      if self.aug:rm(path.."[. = '']") > 0 then gc(pth.parent(path)) end
+   end
+   for p, _ in pairs(gcpaths) do gc(p) end
+
+   if self.aug:save() ~= 0 then
+      print('Augeas save failed')
+      for _, ep in ipairs(self.aug:match('/augeas//error')) do
+	 print(ep, self.aug:get(ep))
+      end
+      assert(false)
+   end
+end
diff --git a/acf/persistence/backends/volatile.lua b/acf/persistence/backends/volatile.lua
index 339f937..7322323 100644
--- a/acf/persistence/backends/volatile.lua
+++ b/acf/persistence/backends/volatile.lua
@@ -5,14 +5,7 @@ See LICENSE file for license details
 
 module(..., package.seeall)
 
-local copy = require('acf.util').copy
-
-
-local function keys(tbl)
-   local res = {}
-   for k, v in pairs(tbl) do table.insert(res, k) end
-   return res
-end
+local util = require('acf.util')
 
 
 backend = require('acf.object').class()
@@ -31,7 +24,7 @@ end
 
 function backend:get(path, tpe)
    local res = self:_get(path)
-   return type(res) == 'table' and keys(res) or res
+   return type(res) == 'table' and util.keys(res) or res
 end
 
 function backend:_set(path, tpe, value)
@@ -40,7 +33,7 @@ function backend:_set(path, tpe, value)
    if #path == 0 then self.data = value
 
    else
-      local comps = copy(path)
+      local comps = util.copy(path)
       local name = comps[#comps]
       table.remove(comps)
       self:_get(comps)[name] = value
diff --git a/acf/util.lua b/acf/util.lua
index 8dd54cc..adb1e31 100644
--- a/acf/util.lua
+++ b/acf/util.lua
@@ -23,6 +23,12 @@ function copy(var)
    return type(var) == 'table' and setdefaults({}, var) or var
 end
 
+function keys(tbl)
+   local res = {}
+   for k, v in pairs(tbl) do table.insert(res, k) end
+   return res
+end
+
 function map(func, tbl)
    local res = {}
    for k, v in pairs(tbl) do res[k] = func(copy(v)) end