Implement LSP `workspace/configuration` and `workspace/didChangeConfiguration` (#1684)

* Implement LSP `workspace/configuration` request

* Implement LSP `workspace/didChangeConfiguration` notification.

* Simplify retrieval of LSP configuration

* Implement suggestions from PR discussion

Co-authored-by: Triton171 <triton0171@gmail.com>

2 files changed, 28 insertions, 0 deletions

diff --git a/helix-lsp/src/client.rs b/helix-lsp/src/client.rs
index 362498cb..1ce5158b 100644
--- a/helix-lsp/src/client.rs
+++ b/helix-lsp/src/client.rs
@@ -113,6 +113,10 @@ impl Client {
         self.offset_encoding
     }
 
+    pub fn config(&self) -> Option<&Value> {
+        self.config.as_ref()
+    }
+
     /// Execute a RPC request on the language server.
     async fn request<R: lsp::request::Request>(&self, params: R::Params) -> Result<R::Result>
     where
@@ -246,6 +250,13 @@ impl Client {
             root_uri: root,
             initialization_options: self.config.clone(),
             capabilities: lsp::ClientCapabilities {
+                workspace: Some(lsp::WorkspaceClientCapabilities {
+                    configuration: Some(true),
+                    did_change_configuration: Some(lsp::DynamicRegistrationClientCapabilities {
+                        dynamic_registration: Some(false),
+                    }),
+                    ..Default::default()
+                }),
                 text_document: Some(lsp::TextDocumentClientCapabilities {
                     completion: Some(lsp::CompletionClientCapabilities {
                         completion_item: Some(lsp::CompletionItemCapability {
@@ -331,6 +342,16 @@ impl Client {
     }
 
     // -------------------------------------------------------------------------------------------
+    // Workspace
+    // -------------------------------------------------------------------------------------------
+
+    pub fn did_change_configuration(&self, settings: Value) -> impl Future<Output = Result<()>> {
+        self.notify::<lsp::notification::DidChangeConfiguration>(
+            lsp::DidChangeConfigurationParams { settings },
+        )
+    }
+
+    // -------------------------------------------------------------------------------------------
     // Text document
     // -------------------------------------------------------------------------------------------
 
diff --git a/helix-lsp/src/lib.rs b/helix-lsp/src/lib.rs
index 109546d0..389dfb4d 100644
--- a/helix-lsp/src/lib.rs
+++ b/helix-lsp/src/lib.rs
@@ -191,6 +191,7 @@ pub mod util {
 pub enum MethodCall {
     WorkDoneProgressCreate(lsp::WorkDoneProgressCreateParams),
     ApplyWorkspaceEdit(lsp::ApplyWorkspaceEditParams),
+    WorkspaceConfiguration(lsp::ConfigurationParams),
 }
 
 impl MethodCall {
@@ -209,6 +210,12 @@ impl MethodCall {
                     .expect("Failed to parse ApplyWorkspaceEdit params");
                 Self::ApplyWorkspaceEdit(params)
             }
+            lsp::request::WorkspaceConfiguration::METHOD => {
+                let params: lsp::ConfigurationParams = params
+                    .parse()
+                    .expect("Failed to parse WorkspaceConfiguration params");
+                Self::WorkspaceConfiguration(params)
+            }
             _ => {
                 log::warn!("unhandled lsp request: {}", method);
                 return None;