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libya.ng.path_data: wip
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@eugeneia
eugeneia committed Oct 31, 2022
1 parent de2acbc commit c3423ec
Showing 1 changed file with 52 additions and 103 deletions.
155 changes: 52 additions & 103 deletions src/lib/yang/path_data.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -3,134 +3,80 @@
module(..., package.seeall)

local ffi = require("ffi")
local lib = require("core.lib")
local data = require("lib.yang.data")
local value = require("lib.yang.value")
local schema = require("lib.yang.schema")
local parse_path = require("lib.yang.path").parse_path
local path = require("lib.yang.path")
local parse_path = path.parse_path
local util = require("lib.yang.util")
local list = require("lib.yang.list")
local normalize_id = data.normalize_id

local function table_keys(t)
local ret = {}
for k, v in pairs(t) do table.insert(ret, k) end
return ret
end

function prepare_array_lookup(query)
if not lib.equal(table_keys(query), {"position()"}) then
error("Invalid query: leaf-list can only be indexed by position.")
end
local idx = tonumber(query["position()"])
if idx < 1 or idx ~= math.floor(idx) then
error("Invalid query: leaf-list can only be indexed by positive integers.")
end
return idx
end

function prepare_list_lookup(grammar, query)
if not grammar.list.has_key then
error("Invalid query: list has no key.")
end
local key = {}
for k,_ in pairs(query) do
if not grammar.keys[k] then
error("Invalid path:'"..k.."' is not a list key.")
end
end
for k,grammar in pairs(grammar.keys) do
local v = query[k] or grammar.default
if v == nil then
error("Invalid query: missing required key '"..k.."'")
end
local key_primitive_type = grammar.argument_type.primitive_type
local parser = value.types[key_primitive_type].parse
key[normalize_id(k)] = parser(v, 'path query value')
end
return key
end

local function compute_struct_getter(grammar, name, getter)
local child_grammar = grammar.members[name]
if not child_grammar then
for member_name, member in pairs(grammar.members) do
if child_grammar then break end
if member.type == 'choice' then
for case_name, case in pairs(member.choices) do
if child_grammar then break end
if case[name] then child_grammar = case[name] end
end
end
end
end
if not child_grammar then
error("Struct has no field named '"..name.."'.")
end
local function compute_struct_getter(name, getter)
local id = normalize_id(name)
local function child_getter(data)
return function (data)
local struct = getter(data)
local child = struct[id]
if child == nil then
error("Struct instance has no field named '"..name.."'.")
if struct[id] ~= nil then
return struct[id]
else
error("Container has no member '"..name.."'.")
end
return child
end
return child_grammar, child_getter
end

local function compute_array_getter(grammar, query, getter)
local idx = prepare_array_lookup(query)
-- Pretend that array elements are scalars.
local child_grammar = {type="scalar", argument_type=grammar.element_type,
ctype=grammar.ctype}
local function child_getter(data)
local function compute_array_getter(idx, getter)
return function (data)
local array = getter(data)
if idx > #array then error("Index out of bounds") end
if idx > #array then
error("Index "..idx.." is out of bounds.")
end
return array[idx]
end
return child_grammar, child_getter
end

local function compute_list_getter(grammar, query, getter)
local key = prepare_list_lookup(grammar, query)
-- Pretend that list entries are structs.
local child_grammar = {type="struct", members=grammar.values,
ctype=grammar.value_ctype}
local function child_getter(data)
local function compute_list_getter(key, getter)
return function (data)
local l = list.object(getter(data))
local data = l:find_entry(key)
if data == nil then error("Not found") end
return data
local entry = l:find_entry(key)
if entry ~= nil then
return data
else
error("List has no such entry.")
end
end
return child_grammar, child_getter
end

local function compute_getter(grammar, name, query, getter)
local function compute_getter(grammar, part, getter)
if grammar.type == 'struct' then
grammar, getter = compute_struct_getter(grammar, name, getter)
getter = compute_struct_getter(part.name, getter)
grammar = part.grammar
else
error("Invalid path: '"..name.."' is not a container.")
end
if #table_keys(query) > 0 then
if part.key then
if grammar.type == 'array' then
return compute_array_getter(grammar, query, getter)
getter = compute_array_getter(part.key, getter)
-- Pretend that array elements are scalars.
grammar = {type="scalar", argument_type=grammar.element_type,
ctype=grammar.ctype}
elseif grammar.type == 'list' then
return compute_list_getter(grammar, query, getter)
getter = compute_list_getter(part.key, getter)
-- Pretend that list entries are structs.
grammar = {type="struct", members=grammar.values,
ctype=grammar.value_ctype}
else
error("Invalid path: '"..name.."' can not be queried.")
end
end
return getter, grammar
end

-- Returns a resolver for a particular schema and *lua* path.
function resolver(grammar, path)
if type(path) == 'string' then
path = parse_path(path)
end
path = parse_path(path, grammar)
local getter = function(data) return data end
for _, elt in ipairs(path) do
getter, grammar = compute_getter(grammar, elt.name, elt.query, getter)
for _, part in ipairs(path) do
getter, grammar = compute_getter(grammar, part, getter)
end
return getter, grammar
end
Expand Down Expand Up @@ -188,10 +134,10 @@ local function setter_for_grammar(grammar, path)
if path == "/" then
return function(config, subconfig) return subconfig end
end
local head = parse_path(path)
local head = parse_path(path, grammar)
local tail = table.remove(head)
local tail_name, query = tail.name, tail.query
if lib.equal(query, {}) then
local tail_name, key = tail.name, tail.key
if not key then
-- No query; the simple case.
local getter, grammar = resolver(grammar, head)
if grammar.type ~= 'struct' then
Expand All @@ -209,14 +155,13 @@ local function setter_for_grammar(grammar, path)
table.insert(head, {name=tail_name, query={}})
local getter, grammar = resolver(grammar, head)
if grammar.type == 'array' then
local idx = prepare_array_lookup(query)
local idx = key
return function(config, subconfig)
local array = getter(config)
array[idx] = subconfig
return config
end
elseif grammar.type == 'list' then
local key = prepare_list_lookup(grammar, query)
return function (config, subconfig)
local l = list.object(getter(config))
l:add_or_update_entry(key, subconfig)
Expand All @@ -238,7 +183,6 @@ end
setter_for_schema_by_name = util.memoize(setter_for_schema_by_name)

local function adder_for_grammar(grammar, path)
local top_grammar = grammar
local getter, grammar = resolver(grammar, path)
if grammar.type == 'array' then
return function(config, subconfig)
Expand Down Expand Up @@ -279,14 +223,13 @@ end
adder_for_schema_by_name = util.memoize(adder_for_schema_by_name)

local function remover_for_grammar(grammar, path)
local top_grammar = grammar
local head = parse_path(path)
local head = parse_path(path, grammar)
local tail = table.remove(head)
local tail_name, query = tail.name, tail.query
local tail_name, key = tail.name, tail.key
table.insert(head, {name=tail_name, query={}})
local getter, grammar = resolver(grammar, head)
if grammar.type == 'array' then
local idx = prepare_array_lookup(query)
local idx = key
return function(config)
local cur = getter(config)
if idx > #cur then
Expand All @@ -296,7 +239,6 @@ local function remover_for_grammar(grammar, path)
return config
end
elseif grammar.type == 'list' then
local key = prepare_list_lookup(grammar, query)
return function(config)
local l = list.object(getter(config))
if not l:remove_entry(key) then
Expand All @@ -319,6 +261,13 @@ function remover_for_schema_by_name (schema_name, path)
end
remover_for_schema_by_name = util.memoize(remover_for_schema_by_name)

function visitor_from_grammar(grammar, what, visit)
local visitor



end

function leafref_checker_from_grammar(grammar)
-- Converts a relative path to an absolute path.
-- TODO: Consider moving it to /lib/yang/path.lua.
Expand Down Expand Up @@ -482,7 +431,7 @@ local function uniqueness_checker(grammar, name)
local function has_collision(list, collision)
-- Sad quadratic loop
for i, x in ipairs(list) do
for j, y in ipairs(list) does
for j, y in ipairs(list) do
if i == j then break end
if collision(x, y) then
return false
Expand Down

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