Files
sourcekit-lsp/Sources/SourceKitLSP/Clang/ClangLanguageServer.swift
2023-06-02 13:36:07 -04:00

589 lines
20 KiB
Swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
import Foundation
import LanguageServerProtocol
import LanguageServerProtocolJSONRPC
import LSPLogging
import SKCore
import SKSupport
import struct TSCBasic.AbsolutePath
#if os(Windows)
import WinSDK
#endif
extension NSLock {
/// NOTE: Keep in sync with SwiftPM's 'Sources/Basics/NSLock+Extensions.swift'
fileprivate func withLock<T>(_ body: () throws -> T) rethrows -> T {
lock()
defer { unlock() }
return try body()
}
}
/// A thin wrapper over a connection to a clangd server providing build setting handling.
///
/// In addition, it also intercepts notifications and replies from clangd in order to do things
/// like witholding diagnostics when fallback build settings are being used.
final class ClangLanguageServerShim: LanguageServer, ToolchainLanguageServer {
/// The connection to the clangd LSP. `nil` until `startClangdProcesss` has been called.
var clangd: Connection!
/// Capabilities of the clangd LSP, if received.
var capabilities: ServerCapabilities? = nil
/// Path to the clang binary.
let clangPath: AbsolutePath?
/// Path to the `clangd` binary.
let clangdPath: AbsolutePath
let clangdOptions: [String]
/// Resolved build settings by file. Must be accessed with the `lock`.
private var buildSettingsByFile: [DocumentURI: ClangBuildSettings] = [:]
/// Lock protecting `buildSettingsByFile`.
private var lock: NSLock = NSLock()
/// The current state of the `clangd` language server.
/// Changing the property automatically notified the state change handlers.
private var state: LanguageServerState {
didSet {
// `state` must only be set from `queue`.
dispatchPrecondition(condition: .onQueue(queue))
for handler in stateChangeHandlers {
handler(oldValue, state)
}
}
}
private var stateChangeHandlers: [(_ oldState: LanguageServerState, _ newState: LanguageServerState) -> Void] = []
/// The date at which `clangd` was last restarted.
/// Used to delay restarting in case of a crash loop.
private var lastClangdRestart: Date?
/// Whether or not a restart of `clangd` has been scheduled.
/// Used to make sure we are not restarting `clangd` twice.
private var clangRestartScheduled = false
/// The `InitializeRequest` with which `clangd` was originally initialized.
/// Stored so we can replay the initialization when clangd crashes.
private var initializeRequest: InitializeRequest?
/// The workspace this `ClangLanguageServer` was opened for.
/// `clangd` doesn't have support for multi-root workspaces, so we need to start a separate `clangd` instance for every workspace root.
private weak var workspace: Workspace?
/// A callback with which `ClangLanguageServer` can request its owner to reopen all documents in case it has crashed.
private let reopenDocuments: (ToolchainLanguageServer) -> Void
/// While `clangd` is running, its PID.
#if os(Windows)
private var hClangd: HANDLE = INVALID_HANDLE_VALUE
#else
private var clangdPid: Int32?
#endif
/// Creates a language server for the given client referencing the clang binary specified in `toolchain`.
/// Returns `nil` if `clangd` can't be found.
public init?(
client: LocalConnection,
toolchain: Toolchain,
options: SourceKitServer.Options,
workspace: Workspace,
reopenDocuments: @escaping (ToolchainLanguageServer) -> Void
) throws {
guard let clangdPath = toolchain.clangd else {
return nil
}
self.clangPath = toolchain.clang
self.clangdPath = clangdPath
self.clangdOptions = options.clangdOptions
self.workspace = workspace
self.reopenDocuments = reopenDocuments
self.state = .connected
super.init(client: client)
try startClangdProcesss()
}
func canHandle(workspace: Workspace) -> Bool {
// We launch different clangd instance for each workspace because clangd doesn't have multi-root workspace support.
return workspace === self.workspace
}
func addStateChangeHandler(handler: @escaping (LanguageServerState, LanguageServerState) -> Void) {
queue.async {
self.stateChangeHandlers.append(handler)
}
}
/// Start the `clangd` process, either on creation of the `ClangLanguageServerShim` or after `clangd` has crashed.
private func startClangdProcesss() throws {
// Since we are starting a new clangd process, reset the build settings we have transmitted to clangd
buildSettingsByFile = [:]
let usToClangd: Pipe = Pipe()
let clangdToUs: Pipe = Pipe()
let connectionToClangd = JSONRPCConnection(
protocol: MessageRegistry.lspProtocol,
inFD: clangdToUs.fileHandleForReading,
outFD: usToClangd.fileHandleForWriting
)
self.clangd = connectionToClangd
connectionToClangd.start(receiveHandler: self) {
// FIXME: keep the pipes alive until we close the connection. This
// should be fixed systemically.
withExtendedLifetime((usToClangd, clangdToUs)) {}
}
let process = Foundation.Process()
process.executableURL = clangdPath.asURL
process.arguments = [
"-compile_args_from=lsp", // Provide compiler args programmatically.
"-background-index=false", // Disable clangd indexing, we use the build
"-index=false" // system index store instead.
] + clangdOptions
process.standardOutput = clangdToUs
process.standardInput = usToClangd
process.terminationHandler = { [weak self] process in
log("clangd exited: \(process.terminationReason) \(process.terminationStatus)")
connectionToClangd.close()
guard let self = self else { return }
self.queue.async {
#if os(Windows)
self.hClangd = INVALID_HANDLE_VALUE
#else
self.clangdPid = nil
#endif
if process.terminationStatus != 0 {
self.state = .connectionInterrupted
self.restartClangd()
}
}
}
try process.run()
#if os(Windows)
self.hClangd = process.processHandle
#else
self.clangdPid = process.processIdentifier
#endif
}
/// Restart `clangd` after it has crashed.
/// Delays restarting of `clangd` in case there is a crash loop.
private func restartClangd() {
queue.async {
precondition(self.state == .connectionInterrupted)
precondition(self.clangRestartScheduled == false)
self.clangRestartScheduled = true
guard let initializeRequest = self.initializeRequest else {
log("clangd crashed before it was sent an InitializeRequest.", level: .error)
return
}
let restartDelay: Int
if let lastClangdRestart = self.lastClangdRestart, Date().timeIntervalSince(lastClangdRestart) < 30 {
log("clangd has already been restarted in the last 30 seconds. Delaying another restart by 10 seconds.", level: .info)
restartDelay = 10
} else {
restartDelay = 0
}
self.lastClangdRestart = Date()
DispatchQueue.global(qos: .default).asyncAfter(deadline: .now() + .seconds(restartDelay)) {
self.clangRestartScheduled = false
do {
try self.startClangdProcesss()
// FIXME: We assume that clangd will return the same capabilites after restarting.
// Theoretically they could have changed and we would need to inform SourceKitServer about them.
// But since SourceKitServer more or less ignores them right now anyway, this should be fine for now.
_ = try self.initializeSync(initializeRequest)
self.clientInitialized(InitializedNotification())
self.reopenDocuments(self)
self.queue.async {
self.state = .connected
}
} catch {
log("Failed to restart clangd after a crash.", level: .error)
}
}
}
}
public override func _registerBuiltinHandlers() {
_register(ClangLanguageServerShim.publishDiagnostics)
}
public override func _handleUnknown<R>(_ req: Request<R>) {
guard req.clientID != ObjectIdentifier(clangd) else {
forwardRequest(req, to: client)
return
}
super._handleUnknown(req)
}
public override func _handleUnknown<N>(_ note: Notification<N>) {
if note.clientID == ObjectIdentifier(clangd) {
client.send(note.params)
}
}
/// Forwards a request to the given connection, taking care of replying to the original request
/// and cancellation, while providing a callback with the response for additional processing.
///
/// Immediately after `handler` returns, this passes the result to the original reply handler by
/// calling `request.reply(result)`.
///
/// The cancellation token from the original request is automatically linked to the forwarded
/// request such that cancelling the original request will cancel the forwarded request.
///
/// - Parameters:
/// - request: The request to forward.
/// - to: Where to forward the request (e.g. self.clangd).
/// - handler: An optional closure that will be called with the result of the request.
func forwardRequest<R>(
_ request: Request<R>,
to: Connection,
_ handler: ((LSPResult<R.Response>) -> Void)? = nil)
{
let id = to.send(request.params, queue: queue) { result in
handler?(result)
request.reply(result)
}
request.cancellationToken.addCancellationHandler {
to.send(CancelRequestNotification(id: id))
}
}
/// Forward the given `notification` to `clangd` by asynchronously switching to `queue` for a thread-safe access to `clangd`.
private func forwardNotificationToClangdOnQueue<Notification>(_ notification: Notification) where Notification: NotificationType {
queue.async {
self.clangd.send(notification)
}
}
func _crash() {
self.queue.async {
// Since `clangd` doesn't have a method to crash it, kill it.
#if os(Windows)
if self.hClangd != INVALID_HANDLE_VALUE {
// FIXME(compnerd) this is a bad idea - we can potentially deadlock the
// process if a kobject is a pending state. Unfortunately, the
// `OpenProcess(PROCESS_TERMINATE, ...)`, `CreateRemoteThread`,
// `ExitProcess` dance, while safer, can also indefinitely hang as
// `CreateRemoteThread` may not be serviced depending on the state of
// the process. This just attempts to terminate the process, risking a
// deadlock and resource leaks.
_ = TerminateProcess(self.hClangd, 0)
}
#else
if let pid = self.clangdPid {
kill(pid, SIGKILL)
}
#endif
}
}
/// Forward the given `request` to `clangd` by asynchronously switching to `queue` for a thread-safe access to `clangd`.
private func forwardRequestToClangdOnQueue<R>(_ request: Request<R>, _ handler: ((LSPResult<R.Response>) -> Void)? = nil) {
queue.async {
self.forwardRequest(request, to: self.clangd, handler)
}
}
}
// MARK: - LanguageServer
extension ClangLanguageServerShim {
/// Intercept clangd's `PublishDiagnosticsNotification` to withold it if we're using fallback
/// build settings.
func publishDiagnostics(_ note: Notification<PublishDiagnosticsNotification>) {
let params = note.params
let buildSettings = self.lock.withLock {
return self.buildSettingsByFile[params.uri]
}
let isFallback = buildSettings?.isFallback ?? true
guard isFallback else {
client.send(note.params)
return
}
// Fallback: send empty publish notification instead.
client.send(PublishDiagnosticsNotification(
uri: params.uri, version: params.version, diagnostics: []))
}
}
// MARK: - ToolchainLanguageServer
extension ClangLanguageServerShim {
func initializeSync(_ initialize: InitializeRequest) throws -> InitializeResult {
return try queue.sync {
// Store the initialize request so we can replay it in case clangd crashes
self.initializeRequest = initialize
let result = try clangd.sendSync(initialize)
self.capabilities = result.capabilities
return result
}
}
public func clientInitialized(_ initialized: InitializedNotification) {
forwardNotificationToClangdOnQueue(initialized)
}
public func shutdown(callback: @escaping () -> Void) {
queue.async {
_ = self.clangd.send(ShutdownRequest(), queue: self.queue) { [weak self] _ in
self?.clangd.send(ExitNotification())
if let localConnection = self?.client as? LocalConnection {
localConnection.close()
}
callback()
}
}
}
// MARK: - Text synchronization
public func openDocument(_ note: DidOpenTextDocumentNotification) {
forwardNotificationToClangdOnQueue(note)
}
public func closeDocument(_ note: DidCloseTextDocumentNotification) {
forwardNotificationToClangdOnQueue(note)
// Don't clear cached build settings since we've already informed clangd of the settings for the
// file; if we clear the build settings here we should give clangd dummy build settings to make
// sure we're in sync.
}
public func changeDocument(_ note: DidChangeTextDocumentNotification) {
forwardNotificationToClangdOnQueue(note)
}
public func willSaveDocument(_ note: WillSaveTextDocumentNotification) {
}
public func didSaveDocument(_ note: DidSaveTextDocumentNotification) {
forwardNotificationToClangdOnQueue(note)
}
// MARK: - Build System Integration
public func documentUpdatedBuildSettings(_ uri: DocumentURI, change: FileBuildSettingsChange) {
guard let url = uri.fileURL else {
// FIXME: The clang workspace can probably be reworked to support non-file URIs.
log("Received updated build settings for non-file URI '\(uri)'. Ignoring the update.")
return
}
let clangBuildSettings = ClangBuildSettings(change: change, clangPath: self.clangPath)
logAsync(level: clangBuildSettings == nil ? .warning : .debug) { _ in
let settingsStr = clangBuildSettings == nil ? "nil" : clangBuildSettings!.compilerArgs.description
return "settings for \(uri): \(settingsStr)"
}
let changed = lock.withLock { () -> Bool in
let prevBuildSettings = self.buildSettingsByFile[uri]
guard clangBuildSettings != prevBuildSettings else { return false }
self.buildSettingsByFile[uri] = clangBuildSettings
return true
}
guard changed else { return }
// The compile command changed, send over the new one.
// FIXME: what should we do if we no longer have valid build settings?
if
let compileCommand = clangBuildSettings?.compileCommand,
let pathString = (try? AbsolutePath(validating: url.path))?.pathString
{
let note = DidChangeConfigurationNotification(settings: .clangd(
ClangWorkspaceSettings(
compilationDatabaseChanges: [pathString: compileCommand])))
forwardNotificationToClangdOnQueue(note)
}
}
public func documentDependenciesUpdated(_ uri: DocumentURI) {
// In order to tell clangd to reload an AST, we send it an empty `didChangeTextDocument`
// with `forceRebuild` set in case any missing header files have been added.
// This works well for us as the moment since clangd ignores the document version.
let note = DidChangeTextDocumentNotification(
textDocument: VersionedTextDocumentIdentifier(uri, version: 0),
contentChanges: [],
forceRebuild: true)
forwardNotificationToClangdOnQueue(note)
}
// MARK: - Text Document
/// Returns true if the `ToolchainLanguageServer` will take ownership of the request.
public func definition(_ req: Request<DefinitionRequest>) -> Bool {
// We handle it to provide jump-to-header support for #import/#include.
forwardRequestToClangdOnQueue(req)
return true
}
/// Returns true if the `ToolchainLanguageServer` will take ownership of the request.
public func declaration(_ req: Request<DeclarationRequest>) -> Bool {
// We handle it to provide jump-to-header support for #import/#include.
forwardRequestToClangdOnQueue(req)
return true
}
func completion(_ req: Request<CompletionRequest>) {
forwardRequestToClangdOnQueue(req)
}
func hover(_ req: Request<HoverRequest>) {
forwardRequestToClangdOnQueue(req)
}
func symbolInfo(_ req: Request<SymbolInfoRequest>) {
forwardRequestToClangdOnQueue(req)
}
func documentSymbolHighlight(_ req: Request<DocumentHighlightRequest>) {
forwardRequestToClangdOnQueue(req)
}
func documentSymbol(_ req: Request<DocumentSymbolRequest>) {
forwardRequestToClangdOnQueue(req)
}
func documentColor(_ req: Request<DocumentColorRequest>) {
queue.async {
if self.capabilities?.colorProvider?.isSupported == true {
self.forwardRequestToClangdOnQueue(req)
} else {
req.reply(.success([]))
}
}
}
func documentSemanticTokens(_ req: Request<DocumentSemanticTokensRequest>) {
forwardRequestToClangdOnQueue(req)
}
func documentSemanticTokensDelta(_ req: Request<DocumentSemanticTokensDeltaRequest>) {
forwardRequestToClangdOnQueue(req)
}
func documentSemanticTokensRange(_ req: Request<DocumentSemanticTokensRangeRequest>) {
forwardRequestToClangdOnQueue(req)
}
func colorPresentation(_ req: Request<ColorPresentationRequest>) {
queue.async {
if self.capabilities?.colorProvider?.isSupported == true {
self.forwardRequestToClangdOnQueue(req)
} else {
req.reply(.success([]))
}
}
}
func codeAction(_ req: Request<CodeActionRequest>) {
forwardRequestToClangdOnQueue(req)
}
func inlayHint(_ req: Request<InlayHintRequest>) {
forwardRequestToClangdOnQueue(req)
}
func documentDiagnostic(_ req: Request<DocumentDiagnosticsRequest>) {
forwardRequestToClangdOnQueue(req)
}
func foldingRange(_ req: Request<FoldingRangeRequest>) {
queue.async {
if self.capabilities?.foldingRangeProvider?.isSupported == true {
self.forwardRequestToClangdOnQueue(req)
} else {
req.reply(.success(nil))
}
}
}
func openInterface(_ request: Request<OpenInterfaceRequest>) {
request.reply(.failure(.unknown("unsupported method")))
}
// MARK: - Other
func executeCommand(_ req: Request<ExecuteCommandRequest>) {
forwardRequestToClangdOnQueue(req)
}
}
/// Clang build settings derived from a `FileBuildSettingsChange`.
private struct ClangBuildSettings: Equatable {
/// The compiler arguments, including the program name, argv[0].
public let compilerArgs: [String]
/// The working directory for the invocation.
public let workingDirectory: String
/// Whether the compiler arguments are considered fallback - we withhold diagnostics for
/// fallback arguments and represent the file state differently.
public let isFallback: Bool
public init(_ settings: FileBuildSettings, clangPath: AbsolutePath?, isFallback: Bool = false) {
var arguments = [clangPath?.pathString ?? "clang"] + settings.compilerArguments
if arguments.contains("-fmodules") {
// Clangd is not built with support for the 'obj' format.
arguments.append(contentsOf: [
"-Xclang", "-fmodule-format=raw"
])
}
if let workingDirectory = settings.workingDirectory {
// FIXME: this is a workaround for clangd not respecting the compilation
// database's "directory" field for relative -fmodules-cache-path.
// rdar://63984913
arguments.append(contentsOf: [
"-working-directory", workingDirectory
])
}
self.compilerArgs = arguments
self.workingDirectory = settings.workingDirectory ?? ""
self.isFallback = isFallback
}
public init?(change: FileBuildSettingsChange, clangPath: AbsolutePath?) {
switch change {
case .fallback(let settings): self.init(settings, clangPath: clangPath, isFallback: true)
case .modified(let settings): self.init(settings, clangPath: clangPath, isFallback: false)
case .removedOrUnavailable: return nil
}
}
public var compileCommand: ClangCompileCommand {
return ClangCompileCommand(
compilationCommand: self.compilerArgs, workingDirectory: self.workingDirectory)
}
}