| 🛟 Updated. 28d5985 k33g 5h ago | 1 | package lsp |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "context" |
| 6 | "encoding/json" |
| 7 | "errors" |
| 8 | "fmt" |
| 9 | "io" |
| 10 | "sync" |
| 11 | "time" |
| 12 | |
| 13 | "codeberg.org/turbo-editors/turbo-core/jsonrpc" |
| 14 | ) |
| 15 | |
| 16 | // RequestTimeout caps how long the editor waits for an answer before carrying |
| 17 | // on without one. A completion that takes longer than this is no longer a |
| 18 | // completion; it is an interruption. |
| 19 | const RequestTimeout = 3 * time.Second |
| 20 | |
| 21 | // InitializeTimeout is longer, because a cold server has a project to load |
| 22 | // before it can say hello. |
| 23 | const InitializeTimeout = 30 * time.Second |
| 24 | |
| 25 | // ErrNotReady is returned by every request made before initialisation has |
| 26 | // finished. |
| 27 | var ErrNotReady = errors.New("lsp: the server is not ready yet") |
| 28 | |
| 29 | // Client is a conversation with one language server. |
| 30 | // |
| 31 | // It is safe for concurrent use. Every request is bounded by a timeout, so a |
| 32 | // server that stops answering slows the editor down but never stops it. |
| 33 | type Client struct { |
| 34 | conn *Conn |
| 35 | root string |
| 36 | |
| 37 | // OnDiagnostics is called, from the connection's read loop, whenever the |
| 38 | // server reports the problems in a file. |
| 39 | OnDiagnostics func(path string, diagnostics []Diagnostic) |
| 40 | // OnLog is called with the messages the server wants shown. |
| 41 | OnLog func(message string) |
| 42 | |
| 43 | mu sync.Mutex |
| 44 | ready bool |
| 45 | versions map[string]int |
| 46 | |
| 47 | // name is what the client calls itself in the handshake. A language server |
| 48 | // logs it, and "turbo-go" in the logs of a session that was actually Turbo |
| 49 | // Rust is the kind of small lie that costs somebody an afternoon. |
| 50 | name string |
| 51 | } |
| 52 | |
| 53 | // NewClient returns a client talking over stream, rooted at the directory root |
| 54 | // and introducing itself as name. Call Initialize before anything else. |
| 55 | // |
| 56 | // Taking a stream rather than a command is what lets the whole client be |
| 57 | // tested against a server in the same process, with no child process and no pipes. |
| 58 | // |
| 59 | // client := lsp.NewClient(stream, root, "Turbo Rust") |
| 60 | func NewClient(stream io.ReadWriteCloser, root, name string) *Client { |
| 61 | if name == "" { |
| 62 | name = "turbo-editors" |
| 63 | } |
| 64 | client := &Client{root: root, name: name, versions: map[string]int{}} |
| 65 | client.conn = NewConn(stream, client.handleNotification, client.answerRequest) |
| 66 | return client |
| 67 | } |
| 68 | |
| 69 | // Run reads from the server until the connection ends. Call it in a goroutine |
| 70 | // of its own. |
| 71 | func (c *Client) Run() error { return c.conn.Run() } |
| 72 | |
| 73 | // Ready reports whether initialisation has finished. |
| 74 | func (c *Client) Ready() bool { |
| 75 | c.mu.Lock() |
| 76 | defer c.mu.Unlock() |
| 77 | return c.ready |
| 78 | } |
| 79 | |
| 80 | // Initialize performs the protocol's opening handshake and marks the client |
| 81 | // ready. |
| 82 | func (c *Client) Initialize(ctx context.Context) error { |
| 83 | ctx, cancel := context.WithTimeout(ctx, InitializeTimeout) |
| 84 | defer cancel() |
| 85 | |
| 86 | params := map[string]any{ |
| 87 | "processId": nil, |
| 88 | "rootUri": PathToURI(c.root), |
| 89 | "capabilities": clientCapabilities(), |
| 90 | "clientInfo": map[string]string{"name": c.name}, |
| 91 | } |
| 92 | if err := c.conn.Call(ctx, "initialize", params, nil); err != nil { |
| 93 | return fmt.Errorf("lsp: initialize: %w", err) |
| 94 | } |
| 95 | if err := c.conn.Notify("initialized", map[string]any{}); err != nil { |
| 96 | return fmt.Errorf("lsp: initialized: %w", err) |
| 97 | } |
| 98 | |
| 99 | c.mu.Lock() |
| 100 | c.ready = true |
| 101 | c.mu.Unlock() |
| 102 | return nil |
| 103 | } |
| 104 | |
| 105 | // clientCapabilities describes what this editor can actually make use of. |
| 106 | // |
| 107 | // It is deliberately modest: claiming a capability the editor cannot honour — |
| 108 | // snippet placeholders, say — makes the server send things that then have to |
| 109 | // be thrown away. |
| 110 | func clientCapabilities() map[string]any { |
| 111 | return map[string]any{ |
| 112 | "textDocument": map[string]any{ |
| 113 | "synchronization": map[string]any{ |
| 114 | "didSave": true, |
| 115 | }, |
| 116 | "completion": map[string]any{ |
| 117 | "completionItem": map[string]any{ |
| 118 | "snippetSupport": false, |
| 119 | "documentationFormat": []string{"plaintext"}, |
| 120 | }, |
| 121 | }, |
| 122 | "hover": map[string]any{ |
| 123 | "contentFormat": []string{"plaintext", "markdown"}, |
| 124 | }, |
| 125 | // The three that answer "where else does this name appear". They |
| 126 | // take the same parameters as definition and return the same |
| 127 | // shape, which is why one decoder serves all four. |
| 128 | "references": map[string]any{}, |
| 129 | "implementation": map[string]any{}, |
| 130 | "typeDefinition": map[string]any{}, |
| 131 | "publishDiagnostics": map[string]any{}, |
| 132 | }, |
| 133 | "workspace": map[string]any{ |
| 134 | "configuration": true, |
| 135 | }, |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | // DidOpen tells the server a file is being edited. |
| 140 | func (c *Client) DidOpen(path, text string) error { |
| 141 | c.mu.Lock() |
| 142 | c.versions[path] = 1 |
| 143 | c.mu.Unlock() |
| 144 | |
| 145 | return c.conn.Notify("textDocument/didOpen", DidOpenParams{ |
| 146 | TextDocument: TextDocumentItem{ |
| 147 | URI: PathToURI(path), |
| 148 | LanguageID: "go", |
| 149 | Version: 1, |
| 150 | Text: text, |
| 151 | }, |
| 152 | }) |
| 153 | } |
| 154 | |
| 155 | // DidChange sends a new version of a file. The whole text goes each time; see |
| 156 | // ContentChange for why. |
| 157 | func (c *Client) DidChange(path, text string) error { |
| 158 | c.mu.Lock() |
| 159 | c.versions[path]++ |
| 160 | version := c.versions[path] |
| 161 | c.mu.Unlock() |
| 162 | |
| 163 | return c.conn.Notify("textDocument/didChange", DidChangeParams{ |
| 164 | TextDocument: VersionedTextDocumentIdentifier{URI: PathToURI(path), Version: version}, |
| 165 | ContentChanges: []ContentChange{{Text: text}}, |
| 166 | }) |
| 167 | } |
| 168 | |
| 169 | // DidSave tells the server a file has been written to disk. |
| 170 | func (c *Client) DidSave(path, text string) error { |
| 171 | return c.conn.Notify("textDocument/didSave", DidSaveParams{ |
| 172 | TextDocument: TextDocumentIdentifier{URI: PathToURI(path)}, |
| 173 | Text: text, |
| 174 | }) |
| 175 | } |
| 176 | |
| 177 | // DidClose tells the server a file is no longer being edited. |
| 178 | func (c *Client) DidClose(path string) error { |
| 179 | c.mu.Lock() |
| 180 | delete(c.versions, path) |
| 181 | c.mu.Unlock() |
| 182 | |
| 183 | return c.conn.Notify("textDocument/didClose", DidCloseParams{ |
| 184 | TextDocument: TextDocumentIdentifier{URI: PathToURI(path)}, |
| 185 | }) |
| 186 | } |
| 187 | |
| 188 | // Complete asks what could be typed at a place in a file. |
| 189 | // |
| 190 | // line and runeColumn are the editor's own coordinates; lineText is that |
| 191 | // line's content, which is what the rune-to-UTF-16 conversion needs. |
| 192 | func (c *Client) Complete(ctx context.Context, path string, line, runeColumn int, lineText string) ([]CompletionItem, error) { |
| 193 | if !c.Ready() { |
| 194 | return nil, ErrNotReady |
| 195 | } |
| 196 | ctx, cancel := context.WithTimeout(ctx, RequestTimeout) |
| 197 | defer cancel() |
| 198 | |
| 199 | var raw json.RawMessage |
| 200 | if err := c.conn.Call(ctx, "textDocument/completion", positionParams(path, line, runeColumn, lineText), &raw); err != nil { |
| 201 | return nil, err |
| 202 | } |
| 203 | return decodeCompletion(raw) |
| 204 | } |
| 205 | |
| 206 | // decodeCompletion reads either shape the protocol allows: a bare array of |
| 207 | // items, or a list object wrapping one. |
| 208 | // |
| 209 | // Which it is follows from the first character, not from trying one and |
| 210 | // falling back: a list object whose items happen to be empty decodes as an |
| 211 | // array "successfully" into nothing, and the failure would be silent. |
| 212 | func decodeCompletion(raw json.RawMessage) ([]CompletionItem, error) { |
| 213 | trimmed := bytes.TrimSpace(raw) |
| 214 | if len(trimmed) == 0 || string(trimmed) == "null" { |
| 215 | return nil, nil |
| 216 | } |
| 217 | |
| 218 | if trimmed[0] == '[' { |
| 219 | var items []CompletionItem |
| 220 | if err := json.Unmarshal(trimmed, &items); err != nil { |
| 221 | return nil, fmt.Errorf("lsp: unreadable completion result: %w", err) |
| 222 | } |
| 223 | return items, nil |
| 224 | } |
| 225 | |
| 226 | var list CompletionList |
| 227 | if err := json.Unmarshal(trimmed, &list); err != nil { |
| 228 | return nil, fmt.Errorf("lsp: unreadable completion result: %w", err) |
| 229 | } |
| 230 | return list.Items, nil |
| 231 | } |
| 232 | |
| 233 | // Hover asks what the thing under the cursor is, and returns the text to show |
| 234 | // or the empty string when the server has nothing to say. |
| 235 | func (c *Client) Hover(ctx context.Context, path string, line, runeColumn int, lineText string) (string, error) { |
| 236 | if !c.Ready() { |
| 237 | return "", ErrNotReady |
| 238 | } |
| 239 | ctx, cancel := context.WithTimeout(ctx, RequestTimeout) |
| 240 | defer cancel() |
| 241 | |
| 242 | var hover *Hover |
| 243 | if err := c.conn.Call(ctx, "textDocument/hover", positionParams(path, line, runeColumn, lineText), &hover); err != nil { |
| 244 | return "", err |
| 245 | } |
| 246 | if hover == nil { |
| 247 | return "", nil |
| 248 | } |
| 249 | return hover.Contents.Value, nil |
| 250 | } |
| 251 | |
| 252 | // Definition asks where the thing under the cursor is declared. |
| 253 | func (c *Client) Definition(ctx context.Context, path string, line, runeColumn int, lineText string) ([]Location, error) { |
| 254 | return c.locationRequest(ctx, "textDocument/definition", positionParams(path, line, runeColumn, lineText)) |
| 255 | } |
| 256 | |
| 257 | // TypeDefinition asks where the *type* of the thing under the cursor is |
| 258 | // declared, which is a different question from where the thing itself is. |
| 259 | // |
| 260 | // locations, err := client.TypeDefinition(ctx, path, line, column, lineText) |
| 261 | // |
| 262 | // The answer has the same shape as a definition's, and is read the same way. |
| 263 | func (c *Client) TypeDefinition(ctx context.Context, path string, line, runeColumn int, lineText string) ([]Location, error) { |
| 264 | return c.locationRequest(ctx, "textDocument/typeDefinition", positionParams(path, line, runeColumn, lineText)) |
| 265 | } |
| 266 | |
| 267 | // Implementation asks what implements the thing under the cursor: the types |
| 268 | // satisfying a Go interface, the impl blocks of a Rust trait. |
| 269 | // |
| 270 | // locations, err := client.Implementation(ctx, path, line, column, lineText) |
| 271 | func (c *Client) Implementation(ctx context.Context, path string, line, runeColumn int, lineText string) ([]Location, error) { |
| 272 | return c.locationRequest(ctx, "textDocument/implementation", positionParams(path, line, runeColumn, lineText)) |
| 273 | } |
| 274 | |
| 275 | // References asks where the thing under the cursor is used. |
| 276 | // |
| 277 | // includeDeclaration says whether the declaration itself is one of the |
| 278 | // answers. It is a parameter rather than a constant because the two readings |
| 279 | // are both reasonable — "show me everything that mentions this" wants it, "show |
| 280 | // me the callers" does not — and the caller is the one that knows which |
| 281 | // question was asked. |
| 282 | // |
| 283 | // locations, err := client.References(ctx, path, line, column, lineText, true) |
| 284 | func (c *Client) References(ctx context.Context, path string, line, runeColumn int, lineText string, includeDeclaration bool) ([]Location, error) { |
| 285 | params := referenceParams{ |
| 286 | TextDocumentPositionParams: positionParams(path, line, runeColumn, lineText), |
| 287 | Context: referenceContext{IncludeDeclaration: includeDeclaration}, |
| 288 | } |
| 289 | return c.locationRequest(ctx, "textDocument/references", params) |
| 290 | } |
| 291 | |
| 292 | // referenceParams is a position with the one extra field references takes. |
| 293 | type referenceParams struct { |
| 294 | TextDocumentPositionParams |
| 295 | Context referenceContext `json:"context"` |
| 296 | } |
| 297 | |
| 298 | type referenceContext struct { |
| 299 | IncludeDeclaration bool `json:"includeDeclaration"` |
| 300 | } |
| 301 | |
| 302 | // locationRequest sends one of the four requests that answer with places in |
| 303 | // the code, and reads the answer. |
| 304 | // |
| 305 | // definition, typeDefinition, implementation and references differ only in |
| 306 | // their method name and, for references, one extra parameter. Writing the |
| 307 | // call once means a server that answers a bare object where the specification |
| 308 | // says array — which happens — is handled the same way for all of them. |
| 309 | func (c *Client) locationRequest(ctx context.Context, method string, params any) ([]Location, error) { |
| 310 | if !c.Ready() { |
| 311 | return nil, ErrNotReady |
| 312 | } |
| 313 | ctx, cancel := context.WithTimeout(ctx, RequestTimeout) |
| 314 | defer cancel() |
| 315 | |
| 316 | var raw json.RawMessage |
| 317 | if err := c.conn.Call(ctx, method, params, &raw); err != nil { |
| 318 | return nil, err |
| 319 | } |
| 320 | return decodeLocations(raw) |
| 321 | } |
| 322 | |
| 323 | // decodeLocations reads either shape a definition answer may take: one |
| 324 | // location, or an array of them. |
| 325 | func decodeLocations(raw json.RawMessage) ([]Location, error) { |
| 326 | trimmed := bytes.TrimSpace(raw) |
| 327 | if len(trimmed) == 0 || string(trimmed) == "null" { |
| 328 | return nil, nil |
| 329 | } |
| 330 | |
| 331 | if trimmed[0] == '[' { |
| 332 | var many []Location |
| 333 | if err := json.Unmarshal(trimmed, &many); err != nil { |
| 334 | return nil, fmt.Errorf("lsp: unreadable definition result: %w", err) |
| 335 | } |
| 336 | return many, nil |
| 337 | } |
| 338 | |
| 339 | var one Location |
| 340 | if err := json.Unmarshal(trimmed, &one); err != nil { |
| 341 | return nil, fmt.Errorf("lsp: unreadable definition result: %w", err) |
| 342 | } |
| 343 | return []Location{one}, nil |
| 344 | } |
| 345 | |
| 346 | // positionParams builds the document-and-place parameters most requests take, |
| 347 | // converting the column from runes to UTF-16 units on the way. |
| 348 | func positionParams(path string, line, runeColumn int, lineText string) TextDocumentPositionParams { |
| 349 | return TextDocumentPositionParams{ |
| 350 | TextDocument: TextDocumentIdentifier{URI: PathToURI(path)}, |
| 351 | Position: Position{Line: line, Character: RuneToUTF16(lineText, runeColumn)}, |
| 352 | } |
| 353 | } |
| 354 | |
| 355 | // Shutdown asks the server to stop and closes the connection. |
| 356 | // |
| 357 | // The connection is closed whatever the server answers: a language server that |
| 358 | // will not shut down politely is still one the editor is finished with. |
| 359 | func (c *Client) Shutdown(ctx context.Context) error { |
| 360 | ctx, cancel := context.WithTimeout(ctx, RequestTimeout) |
| 361 | defer cancel() |
| 362 | |
| 363 | callErr := c.conn.Call(ctx, "shutdown", nil, nil) |
| 364 | if callErr == nil { |
| 365 | _ = c.conn.Notify("exit", nil) |
| 366 | } |
| 367 | |
| 368 | closeErr := c.conn.Close() |
| 369 | if callErr != nil { |
| 370 | return callErr |
| 371 | } |
| 372 | return closeErr |
| 373 | } |
| 374 | |
| 375 | // handleNotification deals with what the server sends unprompted. |
| 376 | func (c *Client) handleNotification(method string, params json.RawMessage) { |
| 377 | switch method { |
| 378 | case "textDocument/publishDiagnostics": |
| 379 | c.publishDiagnostics(params) |
| 380 | case "window/showMessage", "window/logMessage": |
| 381 | c.logMessage(params) |
| 382 | } |
| 383 | } |
| 384 | |
| 385 | // publishDiagnostics passes a file's problems on to the editor. |
| 386 | func (c *Client) publishDiagnostics(params json.RawMessage) { |
| 387 | if c.OnDiagnostics == nil { |
| 388 | return |
| 389 | } |
| 390 | var published PublishDiagnosticsParams |
| 391 | if err := json.Unmarshal(params, &published); err != nil { |
| 392 | return |
| 393 | } |
| 394 | c.OnDiagnostics(URIToPath(published.URI), published.Diagnostics) |
| 395 | } |
| 396 | |
| 397 | // logMessage passes a server message on to the editor. |
| 398 | func (c *Client) logMessage(params json.RawMessage) { |
| 399 | if c.OnLog == nil { |
| 400 | return |
| 401 | } |
| 402 | var message struct { |
| 403 | Message string `json:"message"` |
| 404 | } |
| 405 | if err := json.Unmarshal(params, &message); err != nil || message.Message == "" { |
| 406 | return |
| 407 | } |
| 408 | c.OnLog(message.Message) |
| 409 | } |
| 410 | |
| 411 | // answerRequest replies to the server, on the spot. |
| 412 | // |
| 413 | // Every question a language server asks can be answered from what this client |
| 414 | // already knows, so there is nothing to wait for and the deferred half of |
| 415 | // jsonrpc.Request is unused here. An agent's questions cannot be answered that |
| 416 | // way, which is what the deferred half exists for. |
| 417 | func (c *Client) answerRequest(req *jsonrpc.Request) { |
| 418 | req.Reply(c.handleRequest(req.Method, req.Params)) |
| 419 | } |
| 420 | |
| 421 | // handleRequest answers the requests a language server makes of its client. |
| 422 | // |
| 423 | // Answering them matters: gopls and rust-analyzer both ask for configuration during start-up and |
| 424 | // waits for the reply, so a client that ignores the question never finishes |
| 425 | // initialising. |
| 426 | func (c *Client) handleRequest(method string, params json.RawMessage) (any, error) { |
| 427 | switch method { |
| 428 | case "workspace/configuration": |
| 429 | return configurationReply(params), nil |
| 430 | case "window/workDoneProgress/create", "client/registerCapability", "client/unregisterCapability": |
| 431 | return nil, nil |
| 432 | default: |
| 433 | return nil, &ResponseError{Code: CodeMethodNotFound, Message: method} |
| 434 | } |
| 435 | } |
| 436 | |
| 437 | // configurationReply answers a configuration request with one empty settings |
| 438 | // object per item asked about, which means "use your defaults". |
| 439 | func configurationReply(params json.RawMessage) []map[string]any { |
| 440 | var request struct { |
| 441 | Items []json.RawMessage `json:"items"` |
| 442 | } |
| 443 | if err := json.Unmarshal(params, &request); err != nil || len(request.Items) == 0 { |
| 444 | return []map[string]any{{}} |
| 445 | } |
| 446 | |
| 447 | reply := make([]map[string]any, len(request.Items)) |
| 448 | for i := range reply { |
| 449 | reply[i] = map[string]any{} |
| 450 | } |
| 451 | return reply |
| 452 | } |