From 8451a8353b51efaa40540f3794109642cf9b7b04 Mon Sep 17 00:00:00 2001
From: Prabir Shrestha <mail@prabir.me>
Date: Sun, 10 Feb 2019 18:11:30 -0800
Subject: [PATCH] add s:get_active_sources_for_buffer()

---
 autoload/asyncomplete.vim | 73 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 65 insertions(+), 8 deletions(-)

diff --git a/autoload/asyncomplete.vim b/autoload/asyncomplete.vim
index 5e866ec..bd819d2 100644
--- a/autoload/asyncomplete.vim
+++ b/autoload/asyncomplete.vim
@@ -22,27 +22,33 @@ endfunction
 function! s:setup_if_required() abort
     if !s:already_setup
         " register asyncomplete manager
-        call asyncomplete#log('initializing asyncomplete manager', g:asyncomplete_manager)
+        call asyncomplete#log('core', 'initializing asyncomplete manager', g:asyncomplete_manager)
         execute 'let s:manager = function("'. g:asyncomplete_manager  .'")()'
-        call asyncomplete#log('initializing asyncomplete manager complete', s:manager['name'])
+        call asyncomplete#log('core', 'initializing asyncomplete manager complete', s:manager['name'])
 
         " register asyncomplete change manager
         for l:change_manager in g:asyncomplete_change_manager
-            call asyncomplete#log('initializing asyncomplete change manager', l:change_manager)
+            call asyncomplete#log('core', 'initializing asyncomplete change manager', l:change_manager)
             if type(l:change_manager) == type('')
                 execute 'let s:on_change_manager = function("'. l:change_manager  .'")()'
             else
                 let s:on_change_manager = l:change_manager()
             endif
             if has_key(s:on_change_manager, 'error')
-                call asyncomplete#log('initializing asyncomplete change manager failed', s:on_change_manager['name'], s:on_change_manager['error'])
+                call asyncomplete#log('core', 'initializing asyncomplete change manager failed', s:on_change_manager['name'], s:on_change_manager['error'])
             else
                 call s:on_change_manager.register(function('s:on_change'))
-                call asyncomplete#log('initializing asyncomplete change manager complete', s:on_change_manager['name'])
+                call asyncomplete#log('core', 'initializing asyncomplete change manager complete', s:on_change_manager['name'])
                 break
             endif
         endfor
 
+        augroup asyncomplete
+            autocmd!
+            autocmd InsertEnter * call s:on_insert_enter()
+            autocmd InsertLeave * call s:on_insert_leave()
+        augroup END
+
         doautocmd User asyncomplete_setup
         let s:already_setup = 1
     endif
@@ -59,7 +65,7 @@ endfunction
 
 function! asyncomplete#register_source(info) abort
     if has_key(s:sources, a:info['name'])
-        call asyncomplete#log('duplicate asyncomplete#register_source', a:info['name'])
+        call asyncomplete#log('core', 'duplicate asyncomplete#register_source', a:info['name'])
         return -1
     else
         let s:sources[a:info['name']] = a:info
@@ -85,6 +91,57 @@ function! asyncomplete#unregister_source(info_or_server_name) abort
     endif
 endfunction
 
-function! s:on_change() abort
-    call asyncomplete#log('on_change', getline('.'), getcurpos())
+function! s:on_insert_enter() abort
+    call s:get_active_sources_for_buffer() " call to cache
+endfunction
+
+function! s:on_insert_leave() abort
+    let s:active_source_names = []
+endfunction
+
+function! s:on_change() abort
+    if mode() isnot# 'i'
+        return
+    endif
+
+    call asyncomplete#log('core', 'on_change', getline('.'), getcurpos())
+endfunction
+
+function! s:get_active_sources_for_buffer() abort
+    if exists('b:asyncomplete_active_sources')
+        " active sources were cached for buffer
+        return b:asyncomplete_active_sources
+    endif
+
+    call asyncomplete#log('core', 'computing active sources for buffer', bufnr('%'))
+    let b:asyncomplete_active_sources = []
+    for [l:name, l:info] in items(s:sources)
+        let l:blacklisted = 0
+
+        if has_key(l:info, 'blacklist')
+            for l:filetype in l:info['blacklist']
+                if l:filetype == &filetype || l:filetype is# '*'
+                    let l:blacklisted = 1
+                    break
+                endif
+            endfor
+        endif
+
+        if l:blacklisted
+            continue
+        endif
+
+        if has_key(l:info, 'whitelist')
+            for l:filetype in l:info['whitelist']
+                if l:filetype == &filetype || l:filetype is# '*'
+                    let b:asyncomplete_active_sources += [l:name]
+                    break
+                endif
+            endfor
+        endif
+    endfor
+
+    call asyncomplete#log('core', 'active source for buffer', bufnr('%'), b:asyncomplete_active_sources)
+
+    return b:asyncomplete_active_sources
 endfunction