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);

helix-view/src/document.rs

@@ -1489,19 +1489,6 @@ impl Document {
             });
         }
 
-        if emit_lsp_notification {
-            // TODO: move to hook
-            // emit lsp notification
-            for language_server in self.language_servers() {
-                let _ = language_server.text_document_did_change(
-                    self.versioned_identifier(),
-                    &old_doc,
-                    self.text(),
-                    changes,
-                );
-            }
-        }
-
         true
     }
 

helix-view/src/editor.rs

@@ -4,7 +4,7 @@ use crate::{
     document::{
         DocumentOpenError, DocumentSavedEventFuture, DocumentSavedEventResult, Mode, SavePoint,
     },
-    events::DocumentFocusLost,
+    events::{DocumentDidClose, DocumentDidOpen, DocumentFocusLost},
     graphics::{CursorKind, Rect},
     handlers::Handlers,
     info::Info,
@@ -1783,10 +1783,16 @@ impl Editor {
             let id = self.new_document(doc);
             self.launch_language_servers(id);
 
+            helix_event::dispatch(DocumentDidOpen {
+                editor: self,
+                doc: id,
+            });
+
             id
         };
 
         self.switch(id, action);
+
         Ok(id)
     }
 
@@ -1800,7 +1806,7 @@ impl Editor {
     }
 
     pub fn close_document(&mut self, doc_id: DocumentId, force: bool) -> Result<(), CloseError> {
-        let doc = match self.documents.get_mut(&doc_id) {
+        let doc = match self.documents.remove(&doc_id) {
             Some(doc) => doc,
             None => return Err(CloseError::DoesNotExist),
         };
@@ -1811,10 +1817,6 @@ impl Editor {
         // This will also disallow any follow-up writes
         self.saves.remove(&doc_id);
 
-        for language_server in doc.language_servers() {
-            language_server.text_document_did_close(doc.identifier());
-        }
-
         enum Action {
             Close(ViewId),
             ReplaceDoc(ViewId, DocumentId),
@@ -1851,8 +1853,6 @@ impl Editor {
             }
         }
 
-        self.documents.remove(&doc_id);
-
         // If the document we removed was visible in all views, we will have no more views. We don't
         // want to close the editor just for a simple buffer close, so we need to create a new view
         // containing either an existing document, or a brand new document.
@@ -1872,6 +1872,8 @@ impl Editor {
 
         self._refresh();
 
+        helix_event::dispatch(DocumentDidClose { editor: self, doc });
+
         Ok(())
     }
 

helix-view/src/events.rs

@@ -1,9 +1,14 @@
 use helix_core::{ChangeSet, Rope};
 use helix_event::events;
+use helix_lsp::LanguageServerId;
 
 use crate::{Document, DocumentId, Editor, ViewId};
 
 events! {
+    DocumentDidOpen<'a> {
+        editor: &'a mut Editor,
+        doc: DocumentId
+    }
     DocumentDidChange<'a> {
         doc: &'a mut Document,
         view: ViewId,
@@ -11,8 +16,21 @@ events! {
         changes: &'a ChangeSet,
         ghost_transaction: bool
     }
+    DocumentDidClose<'a> {
+        editor: &'a mut Editor,
+        doc: Document
+    }
     SelectionDidChange<'a> { doc: &'a mut Document, view: ViewId }
     DiagnosticsDidChange<'a> { editor: &'a mut Editor, doc: DocumentId }
     // called **after** a document loses focus (but not when its closed)
     DocumentFocusLost<'a> { editor: &'a mut Editor, doc: DocumentId }
+
+    LanguageServerInitialized<'a> {
+        editor: &'a mut Editor,
+        server_id: LanguageServerId
+    }
+    LanguageServerExited<'a> {
+        editor: &'a mut Editor,
+        server_id: LanguageServerId
+    }
 }

helix-view/src/handlers.rs

@@ -46,3 +46,7 @@ impl Handlers {
         send_blocking(&self.signature_hints, event)
     }
 }
+
+pub fn register_hooks(handlers: &Handlers) {
+    lsp::register_hooks(handlers);
+}

helix-view/src/handlers/lsp.rs

@@ -2,13 +2,18 @@ use std::collections::btree_map::Entry;
 use std::fmt::Display;
 
 use crate::editor::Action;
-use crate::events::DiagnosticsDidChange;
+use crate::events::{
+    DiagnosticsDidChange, DocumentDidChange, DocumentDidClose, LanguageServerInitialized,
+};
 use crate::Editor;
 use helix_core::diagnostic::DiagnosticProvider;
 use helix_core::Uri;
+use helix_event::register_hook;
 use helix_lsp::util::generate_transaction_from_edits;
 use helix_lsp::{lsp, LanguageServerId, OffsetEncoding};
 
+use super::Handlers;
+
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub enum SignatureHelpInvoked {
     Automatic,
@@ -381,3 +386,50 @@ impl Editor {
         });
     }
 }
+
+pub fn register_hooks(_handlers: &Handlers) {
+    register_hook!(move |event: &mut LanguageServerInitialized<'_>| {
+        let language_server = event.editor.language_server_by_id(event.server_id).unwrap();
+
+        for doc in event
+            .editor
+            .documents()
+            .filter(|doc| doc.supports_language_server(event.server_id))
+        {
+            let Some(url) = doc.url() else {
+                continue;
+            };
+
+            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);
+        }
+
+        Ok(())
+    });
+
+    register_hook!(move |event: &mut DocumentDidChange<'_>| {
+        // Send textDocument/didChange notifications.
+        if !event.ghost_transaction {
+            for language_server in event.doc.language_servers() {
+                language_server.text_document_did_change(
+                    event.doc.versioned_identifier(),
+                    event.old_text,
+                    event.doc.text(),
+                    event.changes,
+                );
+            }
+        }
+
+        Ok(())
+    });
+
+    register_hook!(move |event: &mut DocumentDidClose<'_>| {
+        // Send textDocument/didClose notifications.
+        for language_server in event.doc.language_servers() {
+            language_server.text_document_did_close(event.doc.identifier());
+        }
+
+        Ok(())
+    });
+}