Add document and LSP lifecycle events, move some callbacks into hooks

This adds events for:

* a document being opened
* a document being closed
* a language server sending the initialized notification
* a language server exiting

and also moves some handling done for these scenarios into hooks,
generally moving more into helix-view. A hook is also added on
`DocumentDidChange` which sends the `text_document_did_change`
notification - this resolves a TODO in `document`.

helix-term/src/application.rs

@@ -704,28 +704,10 @@ impl Application {
                             language_server.did_change_configuration(config.clone());
                         }
 
-                        let docs = self
-                            .editor
-                            .documents()
-                            .filter(|doc| doc.supports_language_server(server_id));
-
-                        // trigger textDocument/didOpen for docs that are already open
-                        for doc in docs {
-                            let url = match doc.url() {
-                                Some(url) => url,
-                                None => continue, // skip documents with no path
-                            };
-
-                            let language_id =
-                                doc.language_id().map(ToOwned::to_owned).unwrap_or_default();
-
-                            language_server.text_document_did_open(
-                                url,
-                                doc.version(),
-                                doc.text(),
-                                language_id,
-                            );
-                        }
+                        helix_event::dispatch(helix_view::events::LanguageServerInitialized {
+                            editor: &mut self.editor,
+                            server_id,
+                        });
                     }
                     Notification::PublishDiagnostics(params) => {
                         let uri = match helix_core::Uri::try_from(params.uri) {
@@ -870,6 +852,11 @@ impl Application {
                             doc.clear_diagnostics_for_language_server(server_id);
                         }
 
+                        helix_event::dispatch(helix_view::events::LanguageServerExited {
+                            editor: &mut self.editor,
+                            server_id,
+                        });
+
                         // Remove the language server from the registry.
                         self.editor.language_servers.remove_by_id(server_id);
                     }

helix-term/src/events.rs

@@ -1,7 +1,8 @@
 use helix_event::{events, register_event};
 use helix_view::document::Mode;
 use helix_view::events::{
-    DiagnosticsDidChange, DocumentDidChange, DocumentFocusLost, SelectionDidChange,
+    DiagnosticsDidChange, DocumentDidChange, DocumentDidClose, DocumentDidOpen, DocumentFocusLost,
+    LanguageServerExited, LanguageServerInitialized, SelectionDidChange,
 };
 
 use crate::commands;
@@ -17,8 +18,12 @@ pub fn register() {
     register_event::<OnModeSwitch>();
     register_event::<PostInsertChar>();
     register_event::<PostCommand>();
+    register_event::<DocumentDidOpen>();
     register_event::<DocumentDidChange>();
+    register_event::<DocumentDidClose>();
     register_event::<DocumentFocusLost>();
     register_event::<SelectionDidChange>();
     register_event::<DiagnosticsDidChange>();
+    register_event::<LanguageServerInitialized>();
+    register_event::<LanguageServerExited>();
 }

helix-term/src/handlers.rs

@@ -29,6 +29,7 @@ pub fn setup(config: Arc<ArcSwap<Config>>) -> Handlers {
         auto_save,
     };
 
+    helix_view::handlers::register_hooks(&handlers);
     completion::register_hooks(&handlers);
     signature_help::register_hooks(&handlers);
     auto_save::register_hooks(&handlers);