diff options
| -rw-r--r-- | util/datamanager.lua | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/util/datamanager.lua b/util/datamanager.lua index a00b9014..4145935e 100644 --- a/util/datamanager.lua +++ b/util/datamanager.lua @@ -506,6 +506,97 @@ local function list_open(username, host, datastore) return setmetatable({ file = file; index = index }, indexed_list_mt); end +local function shift_index(index_filename, index, trim_to, offset) + local index_scratch = index_filename .. "~"; + local new_index, err = io_open(index_scratch, "w"); + if not new_index then + os_remove(index_filename); + return "deleted", err; + end + + local ok, err = new_index:write(index_magic); + if not ok then + new_index:close(); + os_remove(index_filename); + os_remove(index_scratch); + return "deleted", err; + end + + if not index.file or not index.file:seek("set", index_item_size * trim_to) then + new_index:close(); + os_remove(index_filename); + os_remove(index_scratch); + return "deleted"; + else + local pack, unpack = string.pack, string.unpack; + for item in index.file:lines(index_item_size) do + local ok, err = new_index:write(pack(index_fmt, unpack(index_fmt, item) - offset)); + if not ok then + os_remove(index_filename); + os_remove(index_scratch); + return "deleted", err; + end + end + local ok, err = new_index:close(); + if not ok then + os_remove(index_filename); + os_remove(index_scratch); + return "deleted", err; + end + return os_rename(index_scratch, index_filename); + end +end + +local function list_shift(username, host, datastore, trim_to) + if trim_to == 1 then + return true + end + if type(trim_to) ~= "number" or trim_to < 1 then + return nil, "invalid-argument"; + end + local list_filename = getpath(username, host, datastore, "list"); + local index_filename = getpath(username, host, datastore, "lidx"); + local index, err = get_list_index(username, host, datastore); + if not index then + return nil, err; + end + + local new_first = index[trim_to]; + if not new_first then + os_remove(index_filename); + return os_remove(list_filename); + end + + local offset = new_first.start; + if offset == 0 then + return true; + end + + local r, err = io_open(list_filename, "r"); + if not r then + return nil, err; + end + local w, err = io_open(list_filename .. "~", "w"); + if not w then + return nil, err; + end + r:seek("set", offset); + for block in r:lines(0x1000) do + local ok, err = w:write(block); + if not ok then + return nil, err; + end + end + r:close(); + local ok, err = w:close(); + if not ok then + return nil, err; + end + shift_index(index_filename, index, trim_to, offset) + return os_rename(list_filename .. "~", list_filename); +end + + local type_map = { keyval = "dat"; list = "list"; @@ -609,4 +700,5 @@ return { build_list_index = build_list_index; list_open = list_open; + list_shift = list_shift; }; |