From 22328f313d72d9207a85e9f2b4b5ac9e974e43bd Mon Sep 17 00:00:00 2001
From: Rahix <rahix@rahix.de>
Date: Sat, 30 Jan 2021 11:10:11 +0100
Subject: [PATCH] Add fallback when uuid is not available

If the `uuid` module does not exist, fall back to a primitive ID
generation mechanism based on just math.random().  The fallback
mechanism provides the same amount of entropy so we can be sure this
won't degrade quality of the identifiers.
---
 bc.lua | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/bc.lua b/bc.lua
index fa03de9dd7e1..bd4804501ad4 100644
--- a/bc.lua
+++ b/bc.lua
@@ -1,4 +1,3 @@
-local uuid = require("uuid")
 local bit32 = require("bit32")
 
 local Version = {0, 1}
@@ -40,6 +39,23 @@ do
     clock = os.clock
   end
 end
+
+local next_uuid -- Generate a UUID
+do
+  local status, uuid = pcall(require, "uuid")
+  if status and uuid.next ~= nil then
+    next_uuid = uuid.next
+  else
+    -- Fallback to something reasonably close
+    next_uuid = function()
+      local uuid = ""
+      for _ = 1,16 do
+        uuid = uuid..string.format("%02x", math.random(0, 255))
+      end
+      return uuid
+    end
+  end
+end
 -- }}}
 
 -- Network ---------------------------------------------------------------- {{{
@@ -420,7 +436,7 @@ function BaseControl:listen(noun, query, callback)
   if self.listeners[noun] == nil then
     self.listeners[noun] = {}
   end
-  local id = uuid.next()
+  local id = next_uuid()
   self.listeners[noun][id] = {
     query=query,
     callback=callback,