util.datamanager: Add O(1) list indexing with on-disk index
Index file contains offsets and lengths of each item() which allows
seeking directly to each item and reading it without parsing the entire
file.
Also allows tricks like binary search, assuming items have some defined
order.
We take advantage of the 1-based indexing in tables to store a magic
header in the 0 position, so that table index 1 ends up at file index 1.
-- Allow for both require"util.foo" and require"prosody.util.foo" for a
-- transition period while we update all require calls.
if (...) == "prosody.loader" then
if not package.path:find "prosody" then
-- For require"util.foo" also look in paths equivalent to "prosody.util.foo"
package.path = package.path:gsub("([^;]*)(?[^;]*)", "%1prosody/%2;%1%2");
package.cpath = package.cpath:gsub("([^;]*)(?[^;]*)", "%1prosody/%2;%1%2");
end
else
-- When requiring "prosody.x", also look for "x"
for i = #package.searchers, 1, -1 do
local search = package.searchers[i];
table.insert(package.searchers, i, function(module_name)
local lib = module_name:match("^prosody%.(.*)$");
if lib then
return search(lib);
end
end)
end
end
-- Look for already loaded module with or without prefix
setmetatable(package.loaded, {
__index = function(loaded, module_name)
local suffix = module_name:match("^prosody%.(.*)$");
if suffix then
return rawget(loaded, suffix);
end
local prefixed = rawget(loaded, "prosody." .. module_name);
if prefixed ~= nil then
return prefixed;
end
end;
})