blob: cc6e3a0a7c954d2612e5fdf041af989ade3df665 [file] [log] [blame]
//===--- Logger.h - Logger interface for clangd ------------------*- C++-*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
#include "llvm/ADT/Twine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FormatAdapters.h"
#include "llvm/Support/FormatVariadic.h"
namespace clang {
namespace clangd {
/// Interface to allow custom logging in clangd.
class Logger {
virtual ~Logger() = default;
enum Level { Debug, Verbose, Info, Error };
static char indicator(Level L) { return "DVIE"[L]; }
/// Implementations of this method must be thread-safe.
virtual void log(Level, const llvm::formatv_object_base &Message) = 0;
namespace detail {
const char *debugType(const char *Filename);
void log(Logger::Level, const llvm::formatv_object_base &);
// We often want to consume llvm::Errors by value when passing them to log().
// We automatically wrap them in llvm::fmt_consume() as formatv requires.
template <typename T> T &&wrap(T &&V) { return std::forward<T>(V); }
inline decltype(fmt_consume(llvm::Error::success())) wrap(llvm::Error &&V) {
return fmt_consume(std::move(V));
template <typename... Ts>
void log(Logger::Level L, const char *Fmt, Ts &&... Vals) {
detail::log(L, llvm::formatv(Fmt, detail::wrap(std::forward<Ts>(Vals))...));
} // namespace detail
// Clangd logging functions write to a global logger set by LoggingSession.
// If no logger is registered, writes to llvm::errs().
// All accept llvm::formatv()-style arguments, e.g. log("Text={0}", Text).
// elog() is used for "loud" errors and warnings.
// This level is often visible to users.
template <typename... Ts> void elog(const char *Fmt, Ts &&... Vals) {
detail::log(Logger::Error, Fmt, std::forward<Ts>(Vals)...);
// log() is used for information important to understanding a clangd session.
// e.g. the names of LSP messages sent are logged at this level.
// This level could be enabled in production builds to allow later inspection.
template <typename... Ts> void log(const char *Fmt, Ts &&... Vals) {
detail::log(Logger::Info, Fmt, std::forward<Ts>(Vals)...);
// vlog() is used for details often needed for debugging clangd sessions.
// This level would typically be enabled for clangd developers.
template <typename... Ts> void vlog(const char *Fmt, Ts &&... Vals) {
detail::log(Logger::Verbose, Fmt, std::forward<Ts>(Vals)...);
// dlog only logs if --debug was passed, or --debug_only=Basename.
// This level would be enabled in a targeted way when debugging.
#define dlog(...) \
DEBUG_WITH_TYPE(::clang::clangd::detail::debugType(__FILE__), \
::clang::clangd::detail::log(Logger::Debug, __VA_ARGS__))
/// Only one LoggingSession can be active at a time.
class LoggingSession {
LoggingSession(clangd::Logger &Instance);
LoggingSession(LoggingSession &&) = delete;
LoggingSession &operator=(LoggingSession &&) = delete;
LoggingSession(LoggingSession const &) = delete;
LoggingSession &operator=(LoggingSession const &) = delete;
} // namespace clangd
} // namespace clang