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-rw-r--r--util/datamanager.lua92
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;
};