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//===--- JSONRPCDispatcher.h - Main JSON parser entry point -----*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
#include "Logger.h"
#include "Protocol.h"
#include "Trace.h"
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/JSON.h"
#include <iosfwd>
#include <mutex>
namespace clang {
namespace clangd {
/// Encapsulates output and logs streams and provides thread-safe access to
/// them.
class JSONOutput : public Logger {
// FIXME(ibiryukov): figure out if we can shrink the public interface of
// JSONOutput now that we pass Context everywhere.
JSONOutput(llvm::raw_ostream &Outs, llvm::raw_ostream &Logs,
Logger::Level MinLevel, llvm::raw_ostream *InputMirror = nullptr,
bool Pretty = false)
: Pretty(Pretty), MinLevel(MinLevel), Outs(Outs), Logs(Logs),
InputMirror(InputMirror) {}
/// Emit a JSONRPC message.
void writeMessage(const llvm::json::Value &Result);
/// Write a line to the logging stream.
void log(Level, const llvm::formatv_object_base &Message) override;
/// Mirror \p Message into InputMirror stream. Does nothing if InputMirror is
/// null.
/// Unlike other methods of JSONOutput, mirrorInput is not thread-safe.
void mirrorInput(const Twine &Message);
// Whether output should be pretty-printed.
const bool Pretty;
Logger::Level MinLevel;
llvm::raw_ostream &Outs;
llvm::raw_ostream &Logs;
llvm::raw_ostream *InputMirror;
std::mutex StreamMutex;
/// Sends a successful reply.
/// Current context must derive from JSONRPCDispatcher::Handler.
void reply(llvm::json::Value &&Result);
/// Sends an error response to the client, and logs it.
/// Current context must derive from JSONRPCDispatcher::Handler.
void replyError(ErrorCode Code, const llvm::StringRef &Message);
/// Sends a request to the client.
/// Current context must derive from JSONRPCDispatcher::Handler.
void call(llvm::StringRef Method, llvm::json::Value &&Params);
/// Main JSONRPC entry point. This parses the JSONRPC "header" and calls the
/// registered Handler for the method received.
class JSONRPCDispatcher {
// A handler responds to requests for a particular method name.
using Handler = std::function<void(const llvm::json::Value &)>;
/// Create a new JSONRPCDispatcher. UnknownHandler is called when an unknown
/// method is received.
JSONRPCDispatcher(Handler UnknownHandler)
: UnknownHandler(std::move(UnknownHandler)) {}
/// Registers a Handler for the specified Method.
void registerHandler(StringRef Method, Handler H);
/// Parses a JSONRPC message and calls the Handler for it.
bool call(const llvm::json::Value &Message, JSONOutput &Out) const;
llvm::StringMap<Handler> Handlers;
Handler UnknownHandler;
/// Controls the way JSON-RPC messages are encoded (both input and output).
enum JSONStreamStyle {
/// Encoding per the LSP specification, with mandatory Content-Length header.
/// Messages are delimited by a '---' line. Comment lines start with #.
/// Parses input queries from LSP client (coming from \p In) and runs call
/// method of \p Dispatcher for each query.
/// After handling each query checks if \p IsDone is set true and exits the loop
/// if it is.
/// Input stream(\p In) must be opened in binary mode to avoid preliminary
/// replacements of \r\n with \n.
/// We use C-style FILE* for reading as std::istream has unclear interaction
/// with signals, which are sent by debuggers on some OSs.
void runLanguageServerLoop(std::FILE *In, JSONOutput &Out,
JSONStreamStyle InputStyle,
JSONRPCDispatcher &Dispatcher, bool &IsDone);
} // namespace clangd
} // namespace clang