add cmp.get_registered_sources and CmpRegisterSource /CmpUnregisterSource autocmd.

doc/cmp.txt

@@ -154,6 +154,9 @@ NOTE: `<Cmd>lua require('cmp').complete()<CR>` can be used to call these functio
   See |getcmdtype()|.
   NOTE: nvim-cmp does not support the `=` command type.
 
+*cmp.get_registered_sources* ()
+  Get all registered sources.
+
 *cmp.visible* ()
   Return a boolean showing whether the completion menu is visible or not.
 
@@ -427,6 +430,12 @@ autocommands for the User event with the following patterns:
 *CmpReady*
   Invoked when nvim-cmp gets sourced from `plugin/cmp.lua`.
 
+*CmpRegisterSource*
+  Invoke when source was registered.
+
+*CmpUnregisterSource*
+  Invoke when source was un-registered.
+
 ==============================================================================
 Config                                                              *cmp-config*
 

lua/cmp/core.lua

@@ -47,8 +47,11 @@ end
 
 ---Unregister source
 ---@param source_id integer
+---@return cmp.Source?
 core.unregister_source = function(self, source_id)
+  local s = self.sources[source_id]
   self.sources[source_id] = nil
+  return s
 end
 
 ---Get new context
@@ -105,6 +108,12 @@ core.get_sources = function(self, filter)
   return sources
 end
 
+---Return registered sources.
+---@return cmp.Source[]
+core.get_registered_sources = function(self)
+  return self.sources
+end
+
 ---Keypress handler
 core.on_keymap = function(self, keys, fallback)
   local mode = api.get_mode()

lua/cmp/init.lua

@@ -54,13 +54,33 @@ end
 cmp.register_source = function(name, s)
   local src = source.new(name, s)
   cmp.core:register_source(src)
+  vim.api.nvim_exec_autocmds('User', {
+    pattern = 'CmpRegisterSource',
+    data = {
+      source_id = src.id
+    }
+  })
   return src.id
 end
 
 ---Unregister completion source
 ---@param id integer
 cmp.unregister_source = function(id)
-  cmp.core:unregister_source(id)
+  local s = cmp.core:unregister_source(id)
+  if s then
+    vim.api.nvim_exec_autocmds('User', {
+      pattern = 'CmpUnregisterSource',
+      data = {
+        source_id = id
+      }
+    })
+  end
+end
+
+---Get registered sources.
+---@return cmp.Source[]
+cmp.get_registered_sources = function()
+  return cmp.core:get_registered_sources()
 end
 
 ---Get current configuration.