--- a/util/datamanager.lua Tue May 11 02:04:59 2021 +0200
+++ b/util/datamanager.lua Tue May 11 02:09:56 2021 +0200
@@ -7,6 +7,7 @@
--
+local string = string;
local format = string.format;
local setmetatable = setmetatable;
local ipairs = ipairs;
@@ -17,11 +18,13 @@
local os_remove = os.remove;
local os_rename = os.rename;
local tonumber = tonumber;
+local floor = math.floor;
local next = next;
local type = type;
local t_insert = table.insert;
local t_concat = table.concat;
local envloadfile = require"prosody.util.envload".envloadfile;
+local envload = require"prosody.util.envload".envload;
local serialize = require "prosody.util.serialization".serialize;
local lfs = require "lfs";
-- Extract directory separator from package.config (an undocumented string that comes with lua)
@@ -255,6 +258,13 @@
return true, pos;
end
+local index_fmt, index_item_size, index_magic;
+if string.packsize then
+ index_fmt = "TT"; -- struct { size_t start, size_t length }
+ index_item_size = string.packsize(index_fmt);
+ index_magic = string.pack(index_fmt, 7767639, 1); -- Magic string: T9 for "prosody", version number
+end
+
local function list_append(username, host, datastore, data)
if not data then return; end
if callback(username, host, datastore) == false then return true; end
@@ -267,6 +277,22 @@
datastore, msg, where, username or "nil", host or "nil");
return ok, msg;
end
+ if string.packsize then
+ local offset = type(msg) == "number" and msg or 0;
+ local index_entry = string.pack(index_fmt, offset, #data);
+ if offset == 0 then
+ index_entry = index_magic .. index_entry;
+ end
+ local ok, off = append(username, host, datastore, "lidx", index_entry);
+ off = off or 0;
+ -- If this was the first item, then both the data and index offsets should
+ -- be zero, otherwise there's some kind of mismatch and we should drop the
+ -- index and recreate it from scratch
+ -- TODO Actually rebuild the index in this case?
+ if not ok or (off == 0 and offset ~= 0) or (off ~= 0 and offset == 0) then
+ os_remove(getpath(username, host, datastore, "lidx"));
+ end
+ end
return true;
end
@@ -280,6 +306,7 @@
for i, item in ipairs(data) do
d[i] = "item(" .. serialize(item) .. ");\n";
end
+ os_remove(getpath(username, host, datastore, "lidx"));
local ok, msg = atomic_store(getpath(username, host, datastore, "list", true), t_concat(d));
if not ok then
log("error", "Unable to write to %s storage ('%s') for user: %s@%s", datastore, msg, username or "nil", host or "nil");
@@ -294,6 +321,146 @@
return true;
end
+local function build_list_index(username, host, datastore, items)
+ log("debug", "Building index for (%s@%s/%s)", username, host, datastore);
+ local filename = getpath(username, host, datastore, "list");
+ local fh, err, errno = io_open(filename);
+ if not fh then
+ return fh, err, errno;
+ end
+ local prev_pos = 0; -- position before reading
+ local last_item_start = 0;
+
+ if items and items[1] then
+ local last_item = items[#items];
+ last_item_start = fh:seek("set", last_item.start + last_item.length);
+ else
+ items = {};
+ end
+
+ for line in fh:lines() do
+ if line:sub(1, 4) == "item" then
+ if prev_pos ~= 0 then
+ t_insert(items, { start = last_item_start; length = prev_pos - last_item_start });
+ end
+ last_item_start = prev_pos
+ end
+ -- seek position is at the start of the next line within each loop iteration
+ -- so we need to collect the "current" position at the end of the previous
+ prev_pos = fh:seek()
+ end
+ if prev_pos ~= 0 then
+ t_insert(items, { start = last_item_start; length = prev_pos - last_item_start });
+ end
+ return items;
+end
+
+local function store_list_index(username, host, datastore, index)
+ local data = { index_magic };
+ for i, v in ipairs(index) do
+ data[i + 1] = string.pack(index_fmt, v.start, v.length);
+ end
+ local filename = getpath(username, host, datastore, "lidx");
+ return atomic_store(filename, t_concat(data));
+end
+
+local index_mt = {
+ __index = function(t, i)
+ if type(i) ~= "number" or i % 1 ~= 0 or i < 1 then
+ return
+ end
+ if i < 0 then
+ return
+ end
+ local fh = t.file;
+ local pos = i * index_item_size;
+ if fh:seek("set", pos) ~= pos then
+ return nil
+ end
+ local data = fh:read(index_item_size);
+ if not data then
+ return nil
+ end
+ local start, length = string.unpack(index_fmt, data);
+ local v = { start = start; length = length };
+ t[i] = v;
+ return v;
+ end;
+ __len = function(t)
+ -- Account for both the header and the fence post error
+ return floor(t.file:seek("end") / index_item_size) - 1;
+ end;
+}
+
+local function get_list_index(username, host, datastore)
+ log("debug", "Loading index for (%s%s/%s)", username, host, datastore);
+ local index_filename = getpath(username, host, datastore, "lidx");
+ local ih = io_open(index_filename);
+ if ih then
+ local magic = ih:read(#index_magic);
+ if magic ~= index_magic then
+ log("warn", "Index %q has wrong version number (got %q, expected %q)", index_filename, magic, index_magic);
+ -- wrong version or something
+ ih:close();
+ ih = nil;
+ end
+ end
+
+ if ih then
+ return setmetatable({ file = ih }, index_mt);
+ end
+
+ local index, err = build_list_index(username, host, datastore);
+ if not index then
+ return index, err
+ end
+
+ -- TODO How to handle failure to store the index?
+ local dontcare = store_list_index(username, host, datastore, index); -- luacheck: ignore 211/dontcare
+ return index;
+end
+
+local function list_load_one(fh, start, length)
+ if fh:seek("set", start) ~= start then
+ return nil
+ end
+ local raw_data = fh:read(length)
+ if not raw_data or #raw_data ~= length then
+ return
+ end
+ local item;
+ local data, err, errno = envload(raw_data, "@list", {
+ item = function(i)
+ item = i;
+ end;
+ });
+ if not data then
+ return data, err, errno
+ end
+ local success, ret = pcall(data);
+ if not success then
+ return success, ret;
+ end
+ return item;
+end
+
+local indexed_list_mt = {
+ __index = function(t, i)
+ if type(i) ~= "number" or i % 1 ~= 0 or i < 1 then
+ return
+ end
+ local ix = t.index[i];
+ if not ix then
+ return
+ end
+ local item = list_load_one(t.file, ix.start, ix.length);
+ return item;
+ end;
+ __len = function(t)
+ return #t.index;
+ end;
+}
+
local function list_load(username, host, datastore)
local items = {};
local data, err, errno = envloadfile(getpath(username, host, datastore, "list"), {item = function(i) t_insert(items, i); end});
@@ -314,6 +481,27 @@
return items;
end
+local function list_open(username, host, datastore)
+ if not index_magic then
+ log("warn", "Falling back from lazy loading to to loading full list for %s storage for user: %s@%s", datastore, username or "nil", host or "nil");
+ return list_load(username, host, datastore);
+ end
+ local filename = getpath(username, host, datastore, "list");
+ local file, err, errno = io_open(filename);
+ if not file then
+ if errno == ENOENT then
+ return nil;
+ end
+ return file, err, errno;
+ end
+ local index, err = get_list_index(username, host, datastore);
+ if not index then
+ file:close()
+ return index, err;
+ end
+ return setmetatable({ file = file; index = index }, indexed_list_mt);
+end
+
local type_map = {
keyval = "dat";
list = "list";
@@ -414,4 +602,7 @@
purge = purge;
path_decode = decode;
path_encode = encode;
+
+ build_list_index = build_list_index;
+ list_open = list_open;
};