util/queue.lua
author Matthew Wild <mwild1@gmail.com>
Mon, 31 Oct 2022 14:32:02 +0000
branch0.12
changeset 12794 24b55f0e2db9
parent 11118 6a608ecb3471
child 12979 d10957394a3c
permissions -rw-r--r--
mod_http: Allow disabling CORS in the http_cors_override option and by default Fixes #1779. Due to an oversight in the logic, if the user set 'enabled' to false in an override, it would disable the item's requested CORS settings, but still apply Prosody's default CORS policy. This change ensures that 'enabled = false' will now disable CORS entirely for the requested item. Due to the new structure of the code, it was necessary to have a flag to say whether CORS is to be applied at all. Rather than hard-coding 'true' here, I chose to add a new option: 'http_default_cors_enabled'. This is a boolean that allows the operator to disable Prosody's default CORS policy entirely (the one that is used when a module or config does not override it). This makes it easier to disable CORS and then selectively enable it only on services you want it on.

-- Prosody IM
-- Copyright (C) 2008-2015 Matthew Wild
-- Copyright (C) 2008-2015 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

-- Small ringbuffer library (i.e. an efficient FIFO queue with a size limit)
-- (because unbounded dynamically-growing queues are a bad thing...)

local have_utable, utable = pcall(require, "util.table"); -- For pre-allocation of table

local function new(size, allow_wrapping)
	-- Head is next insert, tail is next read
	local head, tail = 1, 1;
	local items = 0; -- Number of stored items
	local t = have_utable and utable.create(size, 0) or {}; -- Table to hold items
	--luacheck: ignore 212/self
	return {
		_items = t;
		size = size;
		count = function (self) return items; end;
		push = function (self, item)
			if items >= size then
				if allow_wrapping then
					tail = (tail%size)+1; -- Advance to next oldest item
					items = items - 1;
				else
					return nil, "queue full";
				end
			end
			t[head] = item;
			items = items + 1;
			head = (head%size)+1;
			return true;
		end;
		pop = function (self)
			if items == 0 then
				return nil;
			end
			local item;
			item, t[tail] = t[tail], 0;
			tail = (tail%size)+1;
			items = items - 1;
			return item;
		end;
		peek = function (self)
			if items == 0 then
				return nil;
			end
			return t[tail];
		end;
		replace = function (self, data)
			if items == 0 then
				return self:push(data);
			end
			t[tail] = data;
			return true;
		end;
		items = function (self)
			return function (_, pos)
				if pos >= items then
					return nil;
				end
				local read_pos = tail + pos;
				if read_pos > self.size then
					read_pos = (read_pos%size);
				end
				return pos+1, t[read_pos];
			end, self, 0;
		end;
		consume = function (self)
			return self.pop, self;
		end;
	};
end

return {
	new = new;
};