ohmers 0.1.0

// Taken from https://raw.githubusercontent.com/soveran/ohm/2.3.0/lib/ohm/lua/save.lua
pub const SAVE:&'static str = "
-- This script receives four parameters, all encoded with
-- MessagePack. The decoded values are used for saving a model
-- instance in Redis, creating or updating a hash as needed and
-- updating zero or more sets (indices) and zero or more hashes
-- (unique indices).
--
-- # model
--
-- Table with one or two attributes:
--    name (model name)
--    id (model instance id, optional)
--
-- If the id is not provided, it is treated as a new record.
--
-- # attrs
--
-- Array with attribute/value pairs.
--
-- # indices
--
-- Fields and values to be indexed. Each key in the indices
-- table is mapped to an array of values. One index is created
-- for each field/value pair.
--
-- # uniques
--
-- Fields and values to be indexed as unique. Unlike indices,
-- values are not enumerable. If a field/value pair is not unique
-- (i.e., if there was already a hash entry for that field and
-- value), an error is returned with the UniqueIndexViolation
-- message and the field that triggered the error.
--
local model   = cmsgpack.unpack(ARGV[1])
local attrs   = cmsgpack.unpack(ARGV[2])
local indices = cmsgpack.unpack(ARGV[3])
local uniques = cmsgpack.unpack(ARGV[4])

local function save(model, attrs)
	if model.id == nil then
		model.id = redis.call(\"INCR\", model.name .. \":id\")
	end

	model.key = model.name .. \":\" .. model.id

	redis.call(\"SADD\", model.name .. \":all\", model.id)
	redis.call(\"DEL\", model.key)

	if math.mod(#attrs, 2) == 1 then
		error(\"Wrong number of attribute/value pairs\")
	end

	if #attrs > 0 then
		redis.call(\"HMSET\", model.key, unpack(attrs))
	end
end

local function index(model, indices)
	for field, enum in pairs(indices) do
		for _, val in ipairs(enum) do
			local key = model.name .. \":indices:\" .. field .. \":\" .. tostring(val)

			redis.call(\"SADD\", model.key .. \":_indices\", key)
			redis.call(\"SADD\", key, model.id)
		end
	end
end

local function remove_indices(model)
	local memo = model.key .. \":_indices\"
	local existing = redis.call(\"SMEMBERS\", memo)

	for _, key in ipairs(existing) do
		redis.call(\"SREM\", key, model.id)
		redis.call(\"SREM\", memo, key)
	end
end

local function unique(model, uniques)
	for field, value in pairs(uniques) do
		local key = model.name .. \":uniques:\" .. field

		redis.call(\"HSET\", model.key .. \":_uniques\", key, value)
		redis.call(\"HSET\", key, value, model.id)
	end
end

local function remove_uniques(model)
	local memo = model.key .. \":_uniques\"

	for _, key in pairs(redis.call(\"HKEYS\", memo)) do
		redis.call(\"HDEL\", key, redis.call(\"HGET\", memo, key))
		redis.call(\"HDEL\", memo, key)
	end
end

local function verify(model, uniques)
	local duplicates = {}

	for field, value in pairs(uniques) do
		local key = model.name .. \":uniques:\" .. field
		local id = redis.call(\"HGET\", key, tostring(value))

		if id and id ~= tostring(model.id) then
			duplicates[#duplicates + 1] = field
		end
	end

	return duplicates, #duplicates ~= 0
end

local duplicates, err = verify(model, uniques)

if err then
	error(\"UniqueIndexViolation: \" .. duplicates[1])
end

save(model, attrs)

remove_indices(model)
index(model, indices)

remove_uniques(model, uniques)
unique(model, uniques)

return tostring(model.id)
";

// Taken from https://raw.githubusercontent.com/soveran/ohm/2.3.0/lib/ohm/lua/delete.lua
pub const DELETE:&'static str = "
-- This script receives three parameters, all encoded with
-- MessagePack. The decoded values are used for deleting a model
-- instance in Redis and removing any reference to it in sets
-- (indices) and hashes (unique indices).
--
-- # model
--
-- Table with three attributes:
--    id (model instance id)
--    key (hash where the attributes will be saved)
--    name (model name)
--
-- # uniques
--
-- Fields and values to be removed from the unique indices.
--
-- # tracked
--
-- Keys that share the lifecycle of this model instance, that
-- should be removed as this object is deleted.
--
local model   = cmsgpack.unpack(ARGV[1])
local uniques = cmsgpack.unpack(ARGV[2])
local tracked = cmsgpack.unpack(ARGV[3])

local function remove_indices(model)
	local memo = model.key .. \":_indices\"
	local existing = redis.call(\"SMEMBERS\", memo)

	for _, key in ipairs(existing) do
		redis.call(\"SREM\", key, model.id)
		redis.call(\"SREM\", memo, key)
	end
end

local function remove_uniques(model, uniques)
	local memo = model.key .. \":_uniques\"

	for field, _ in pairs(uniques) do
		local key = model.name .. \":uniques:\" .. field

		redis.call(\"HDEL\", key, redis.call(\"HGET\", memo, key))
		redis.call(\"HDEL\", memo, key)
	end
end

local function remove_tracked(model, tracked)
	for _, tracked_key in ipairs(tracked) do
		local key = model.key .. \":\" .. tracked_key

		redis.call(\"DEL\", key)
	end
end

local function delete(model)
	local keys = {
		model.key .. \":counters\",
		model.key .. \":_indices\",
		model.key .. \":_uniques\",
		model.key
	}

	redis.call(\"SREM\", model.name .. \":all\", model.id)
	redis.call(\"DEL\", unpack(keys))
end

remove_indices(model)
remove_uniques(model, uniques)
remove_tracked(model, tracked)
delete(model)

return model.id
";