1-- 2-- SPDX-License-Identifier: BSD-2-Clause 3-- 4-- Copyright (c) 2018 Kyle Evans <kevans@FreeBSD.org> 5-- 6-- Redistribution and use in source and binary forms, with or without 7-- modification, are permitted provided that the following conditions 8-- are met: 9-- 1. Redistributions of source code must retain the above copyright 10-- notice, this list of conditions and the following disclaimer. 11-- 2. Redistributions in binary form must reproduce the above copyright 12-- notice, this list of conditions and the following disclaimer in the 13-- documentation and/or other materials provided with the distribution. 14-- 15-- THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16-- ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18-- ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19-- FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20-- DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21-- OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22-- HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23-- LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24-- OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25-- SUCH DAMAGE. 26-- 27 28local hook = {} 29 30local registered_hooks = {} 31 32-- Module exports 33-- Register a hook type; these are the names that hooks may be registered for. 34-- It is expected that modules will register all of their hook types upon 35-- initial load. Other modules may then, at any time, register a hook for these 36-- types. 37-- 38-- Naming convention: hook types should be sensible named, preferably prefixed 39-- with the name of the module that registered them. They would also ideally 40-- describe an action that may or may not match a function name. 41-- e.g. config.reloaded which takes place after config has been reloaded, 42-- possibly from a different source. 43function hook.registerType(hooktype) 44 registered_hooks[hooktype] = {} 45end 46 47function hook.register(hooktype, hookfunc) 48 local selected_hooks = registered_hooks[hooktype] 49 if selected_hooks == nil then 50 print("Tried registering a hook for an unknown hook type: " .. 51 hooktype) 52 return 53 end 54 selected_hooks[#selected_hooks + 1] = hookfunc 55 registered_hooks[hooktype] = selected_hooks 56end 57 58-- Takes a hooktype and runs all functions associated with that specific hook 59-- type in the order that they were registered in. This ordering should likely 60-- not be relied upon. 61function hook.runAll(hooktype, data) 62 local selected_hooks = registered_hooks[hooktype] 63 if selected_hooks == nil then 64 -- This message, and the print() above, should only be seen by 65 -- developers. Hook type registration should have happened at 66 -- module load, so if this hasn't happened then we have messed 67 -- up the order in which we've loaded modules and we need to 68 -- catch that as soon as possible. 69 print("Tried to run hooks for an unknown hook type: " .. 70 hooktype) 71 return 0 72 end 73 if #selected_hooks > 0 then 74 for _, func in ipairs(selected_hooks) do 75 func(data) 76 end 77 end 78 return #selected_hooks 79end 80 81return hook 82