buffer updates: add on_reload callback and handle it in treesitter parser

src/nvim/api/buffer.c

@@ -119,6 +119,10 @@ Integer nvim_buf_line_count(Buffer buffer, Error *err)
 ///             - on_detach: Lua callback invoked on detach. Args:
 ///               - the string "detach"
 ///               - buffer handle
+///             - on_reload: Lua callback invoked on reload. The entire buffer
+///                          content should be considered changed. Args:
+///               - the string "detach"
+///               - buffer handle
 ///             - utf_sizes: include UTF-32 and UTF-16 size of the replaced
 ///               region, as args to `on_lines`.
 ///             - preview: also attach to command preview (i.e. 'inccommand')
@@ -141,50 +145,57 @@ Boolean nvim_buf_attach(uint64_t channel_id,
 
   bool is_lua = (channel_id == LUA_INTERNAL_CALL);
   BufUpdateCallbacks cb = BUF_UPDATE_CALLBACKS_INIT;
+  struct {
+    const char *name;
+    LuaRef *dest;
+  } cbs[] = {
+    { "on_lines", &cb.on_lines },
+    { "on_bytes", &cb.on_bytes },
+    { "on_changedtick", &cb.on_changedtick },
+    { "on_detach", &cb.on_detach },
+    { "on_reload", &cb.on_reload },
+    { NULL, NULL },
+  };
+
   for (size_t i = 0; i < opts.size; i++) {
     String k = opts.items[i].key;
     Object *v = &opts.items[i].value;
-    if (is_lua && strequal("on_lines", k.data)) {
-      if (v->type != kObjectTypeLuaRef) {
-        api_set_error(err, kErrorTypeValidation, "callback is not a function");
-        goto error;
+    bool key_used = false;
+    if (is_lua) {
+      for (size_t j = 0; cbs[j].name; j++) {
+        if (strequal(cbs[j].name, k.data)) {
+          if (v->type != kObjectTypeLuaRef) {
+            api_set_error(err, kErrorTypeValidation,
+                          "%s is not a function", cbs[j].name);
+            goto error;
+          }
+          *(cbs[j].dest) = v->data.luaref;
+          v->data.luaref = LUA_NOREF;
+          key_used = true;
+          break;
+        }
       }
-      cb.on_lines = v->data.luaref;
-      v->data.luaref = LUA_NOREF;
-    } else if (is_lua && strequal("on_bytes", k.data)) {
-      if (v->type != kObjectTypeLuaRef) {
-        api_set_error(err, kErrorTypeValidation, "callback is not a function");
-        goto error;
+
+      if (key_used) {
+        continue;
+      } else if (strequal("utf_sizes", k.data)) {
+        if (v->type != kObjectTypeBoolean) {
+          api_set_error(err, kErrorTypeValidation, "utf_sizes must be boolean");
+          goto error;
+        }
+        cb.utf_sizes = v->data.boolean;
+        key_used = true;
+      } else if (strequal("preview", k.data)) {
+        if (v->type != kObjectTypeBoolean) {
+          api_set_error(err, kErrorTypeValidation, "preview must be boolean");
+          goto error;
+        }
+        cb.preview = v->data.boolean;
+        key_used = true;
       }
-      cb.on_bytes = v->data.luaref;
-      v->data.luaref = LUA_NOREF;
-    } else if (is_lua && strequal("on_changedtick", k.data)) {
-      if (v->type != kObjectTypeLuaRef) {
-        api_set_error(err, kErrorTypeValidation, "callback is not a function");
-        goto error;
-      }
-      cb.on_changedtick = v->data.luaref;
-      v->data.luaref = LUA_NOREF;
-    } else if (is_lua && strequal("on_detach", k.data)) {
-      if (v->type != kObjectTypeLuaRef) {
-        api_set_error(err, kErrorTypeValidation, "callback is not a function");
-        goto error;
-      }
-      cb.on_detach = v->data.luaref;
-      v->data.luaref = LUA_NOREF;
-    } else if (is_lua && strequal("utf_sizes", k.data)) {
-      if (v->type != kObjectTypeBoolean) {
-        api_set_error(err, kErrorTypeValidation, "utf_sizes must be boolean");
-        goto error;
-      }
-      cb.utf_sizes = v->data.boolean;
-    } else if (is_lua && strequal("preview", k.data)) {
-      if (v->type != kObjectTypeBoolean) {
-        api_set_error(err, kErrorTypeValidation, "preview must be boolean");
-        goto error;
-      }
-      cb.preview = v->data.boolean;
-    } else {
+    }
+
+    if (!key_used) {
       api_set_error(err, kErrorTypeValidation, "unexpected key: %s", k.data);
       goto error;
     }

src/nvim/buffer.c

@@ -596,7 +596,7 @@ void close_buffer(win_T *win, buf_T *buf, int action, bool abort_if_last)
 
   // Disable buffer-updates for the current buffer.
   // No need to check `unload_buf`: in that case the function returned above.
-  buf_updates_unregister_all(buf);
+  buf_updates_unload(buf, false);
 
   /*
    * Remove the buffer from the list.
@@ -821,7 +821,7 @@ static void free_buffer_stuff(buf_T *buf, int free_flags)
   map_clear_int(buf, MAP_ALL_MODES, true, true);     // clear local abbrevs
   XFREE_CLEAR(buf->b_start_fenc);
 
-  buf_updates_unregister_all(buf);
+  buf_updates_unload(buf, false);
 }
 
 /*

src/nvim/buffer_defs.h

@@ -488,11 +488,12 @@ typedef struct {
   LuaRef on_bytes;
   LuaRef on_changedtick;
   LuaRef on_detach;
+  LuaRef on_reload;
   bool utf_sizes;
   bool preview;
 } BufUpdateCallbacks;
 #define BUF_UPDATE_CALLBACKS_INIT { LUA_NOREF, LUA_NOREF, LUA_NOREF, \
-                                    LUA_NOREF, false, false }
+                                    LUA_NOREF, LUA_NOREF, false, false }
 
 EXTERN int curbuf_splice_pending INIT(= 0);
 

src/nvim/buffer_updates.c

@@ -135,7 +135,7 @@ void buf_updates_unregister(buf_T *buf, uint64_t channelid)
   }
 }
 
-void buf_updates_unregister_all(buf_T *buf)
+void buf_updates_unload(buf_T *buf, bool can_reload)
 {
   size_t size = kv_size(buf->update_channels);
   if (size) {
@@ -146,9 +146,20 @@ void buf_updates_unregister_all(buf_T *buf)
     kv_init(buf->update_channels);
   }
 
+  size_t j = 0;
   for (size_t i = 0; i < kv_size(buf->update_callbacks); i++) {
     BufUpdateCallbacks cb = kv_A(buf->update_callbacks, i);
-    if (cb.on_detach != LUA_NOREF) {
+    LuaRef thecb = LUA_NOREF;
+
+    bool keep = false;
+    if (can_reload && cb.on_reload != LUA_NOREF) {
+      keep = true;
+      thecb = cb.on_reload;
+    } else if (cb.on_detach != LUA_NOREF) {
+      thecb = cb.on_detach;
+    }
+
+    if (thecb != LUA_NOREF) {
       Array args = ARRAY_DICT_INIT;
       Object items[1];
       args.size = 1;
@@ -158,15 +169,24 @@ void buf_updates_unregister_all(buf_T *buf)
       args.items[0] = BUFFER_OBJ(buf->handle);
 
       textlock++;
-      nlua_call_ref(cb.on_detach, "detach", args, false, NULL);
+      nlua_call_ref(thecb, keep ? "reload" : "detach", args, false, NULL);
       textlock--;
     }
-    free_update_callbacks(cb);
+
+    if (keep) {
+      kv_A(buf->update_callbacks, j++) = kv_A(buf->update_callbacks, i);
+    } else {
+      free_update_callbacks(cb);
+    }
+  }
+  kv_size(buf->update_callbacks) = j;
+  if (kv_size(buf->update_callbacks) == 0) {
+    kv_destroy(buf->update_callbacks);
+    kv_init(buf->update_callbacks);
   }
-  kv_destroy(buf->update_callbacks);
-  kv_init(buf->update_callbacks);
 }
 
+
 void buf_updates_send_changes(buf_T *buf,
                               linenr_T firstline,
                               int64_t num_added,

src/nvim/ex_cmds.c

@@ -2537,13 +2537,13 @@ int do_ecmd(
         goto theend;
       }
       u_unchanged(curbuf);
-      buf_updates_unregister_all(curbuf);
+      buf_updates_unload(curbuf, false);
       buf_freeall(curbuf, BFA_KEEP_UNDO);
 
       // Tell readfile() not to clear or reload undo info.
       readfile_flags = READ_KEEP_UNDO;
     } else {
-      buf_updates_unregister_all(curbuf);
+      buf_updates_unload(curbuf, false);
       buf_freeall(curbuf, 0);  // Free all things for buffer.
     }
     // If autocommands deleted the buffer we were going to re-edit, give

src/nvim/fileio.c

@@ -5076,7 +5076,8 @@ void buf_reload(buf_T *buf, int orig_mode)
         // Mark all undo states as changed.
         u_unchanged(curbuf);
       }
-      buf_updates_unregister_all(curbuf);
+      buf_updates_unload(curbuf, true);
+      curbuf->b_mod_set = true;
     }
   }
   xfree(ea.cmd);