forked from OSchip/llvm-project
99 lines
4.0 KiB
C++
99 lines
4.0 KiB
C++
//===--- Transport.h - sending and receiving LSP messages -------*- C++ -*-===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// The language server protocol is usually implemented by writing messages as
|
|
// JSON-RPC over the stdin/stdout of a subprocess. However other communications
|
|
// mechanisms are possible, such as XPC on mac.
|
|
//
|
|
// The Transport interface allows the mechanism to be replaced, and the JSONRPC
|
|
// Transport is the standard implementation.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_TRANSPORT_H_
|
|
#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_TRANSPORT_H_
|
|
|
|
#include "Feature.h"
|
|
#include "llvm/ADT/StringRef.h"
|
|
#include "llvm/Support/JSON.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
|
|
namespace clang {
|
|
namespace clangd {
|
|
|
|
// A transport is responsible for maintaining the connection to a client
|
|
// application, and reading/writing structured messages to it.
|
|
//
|
|
// Transports have limited thread safety requirements:
|
|
// - messages will not be sent concurrently
|
|
// - messages MAY be sent while loop() is reading, or its callback is active
|
|
class Transport {
|
|
public:
|
|
virtual ~Transport() = default;
|
|
|
|
// Called by Clangd to send messages to the client.
|
|
virtual void notify(llvm::StringRef Method, llvm::json::Value Params) = 0;
|
|
virtual void call(llvm::StringRef Method, llvm::json::Value Params,
|
|
llvm::json::Value ID) = 0;
|
|
virtual void reply(llvm::json::Value ID,
|
|
llvm::Expected<llvm::json::Value> Result) = 0;
|
|
|
|
// Implemented by Clangd to handle incoming messages. (See loop() below).
|
|
class MessageHandler {
|
|
public:
|
|
virtual ~MessageHandler() = default;
|
|
// Handler returns true to keep processing messages, or false to shut down.
|
|
virtual bool onNotify(llvm::StringRef Method, llvm::json::Value) = 0;
|
|
virtual bool onCall(llvm::StringRef Method, llvm::json::Value Params,
|
|
llvm::json::Value ID) = 0;
|
|
virtual bool onReply(llvm::json::Value ID,
|
|
llvm::Expected<llvm::json::Value> Result) = 0;
|
|
};
|
|
// Called by Clangd to receive messages from the client.
|
|
// The transport should in turn invoke the handler to process messages.
|
|
// If handler returns false, the transport should immediately exit the loop.
|
|
// (This is used to implement the `exit` notification).
|
|
// Otherwise, it returns an error when the transport becomes unusable.
|
|
virtual llvm::Error loop(MessageHandler &) = 0;
|
|
};
|
|
|
|
// Controls the way JSON-RPC messages are encoded (both input and output).
|
|
enum JSONStreamStyle {
|
|
// Encoding per the LSP specification, with mandatory Content-Length header.
|
|
Standard,
|
|
// Messages are delimited by a '---' line. Comment lines start with #.
|
|
Delimited
|
|
};
|
|
|
|
// Returns a Transport that speaks JSON-RPC over a pair of streams.
|
|
// The input stream must be opened in binary mode.
|
|
// If InMirror is set, data read will be echoed to it.
|
|
//
|
|
// The use of C-style std::FILE* input deserves some explanation.
|
|
// Previously, std::istream was used. When a debugger attached on MacOS, the
|
|
// process received EINTR, the stream went bad, and clangd exited.
|
|
// A retry-on-EINTR loop around reads solved this problem, but caused clangd to
|
|
// sometimes hang rather than exit on other OSes. The interaction between
|
|
// istreams and signals isn't well-specified, so it's hard to get this right.
|
|
// The C APIs seem to be clearer in this respect.
|
|
std::unique_ptr<Transport>
|
|
newJSONTransport(std::FILE *In, llvm::raw_ostream &Out,
|
|
llvm::raw_ostream *InMirror, bool Pretty,
|
|
JSONStreamStyle = JSONStreamStyle::Standard);
|
|
|
|
#if CLANGD_BUILD_XPC
|
|
// Returns a Transport for macOS based on XPC.
|
|
// Clangd with this transport is meant to be run as bundled XPC service.
|
|
std::unique_ptr<Transport> newXPCTransport();
|
|
#endif
|
|
|
|
} // namespace clangd
|
|
} // namespace clang
|
|
|
|
#endif
|