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//===--- JSONRPCDispatcher.cpp - Main JSON parser entry point -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "JSONRPCDispatcher.h"
#include "ProtocolHandlers.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/YAMLParser.h"
#include <istream>
using namespace clang;
using namespace clangd;
void JSONOutput::writeMessage(const Twine &Message) {
llvm::SmallString<128> Storage;
StringRef M = Message.toStringRef(Storage);
std::lock_guard<std::mutex> Guard(StreamMutex);
// Log without headers.
Logs << "--> " << M << '\n';
Logs.flush();
// Emit message with header.
Outs << "Content-Length: " << M.size() << "\r\n\r\n" << M;
Outs.flush();
}
void JSONOutput::log(const Twine &Message) {
std::lock_guard<std::mutex> Guard(StreamMutex);
Logs << Message;
Logs.flush();
}
void Handler::handleMethod(llvm::yaml::MappingNode *Params, StringRef ID) {
Output.log("Method ignored.\n");
// Return that this method is unsupported.
writeMessage(
R"({"jsonrpc":"2.0","id":)" + ID +
R"(,"error":{"code":-32601}})");
}
void Handler::handleNotification(llvm::yaml::MappingNode *Params) {
Output.log("Notification ignored.\n");
}
void JSONRPCDispatcher::registerHandler(StringRef Method,
std::unique_ptr<Handler> H) {
assert(!Handlers.count(Method) && "Handler already registered!");
Handlers[Method] = std::move(H);
}
static void
callHandler(const llvm::StringMap<std::unique_ptr<Handler>> &Handlers,
llvm::yaml::ScalarNode *Method, llvm::yaml::ScalarNode *Id,
llvm::yaml::MappingNode *Params, Handler *UnknownHandler) {
llvm::SmallString<10> MethodStorage;
auto I = Handlers.find(Method->getValue(MethodStorage));
auto *Handler = I != Handlers.end() ? I->second.get() : UnknownHandler;
if (Id)
Handler->handleMethod(Params, Id->getRawValue());
else
Handler->handleNotification(Params);
}
bool JSONRPCDispatcher::call(StringRef Content) const {
llvm::SourceMgr SM;
llvm::yaml::Stream YAMLStream(Content, SM);
auto Doc = YAMLStream.begin();
if (Doc == YAMLStream.end())
return false;
auto *Root = Doc->getRoot();
if (!Root)
return false;
auto *Object = dyn_cast<llvm::yaml::MappingNode>(Root);
if (!Object)
return false;
llvm::yaml::ScalarNode *Version = nullptr;
llvm::yaml::ScalarNode *Method = nullptr;
llvm::yaml::MappingNode *Params = nullptr;
llvm::yaml::ScalarNode *Id = nullptr;
for (auto &NextKeyValue : *Object) {
auto *KeyString = dyn_cast<llvm::yaml::ScalarNode>(NextKeyValue.getKey());
if (!KeyString)
return false;
llvm::SmallString<10> KeyStorage;
StringRef KeyValue = KeyString->getValue(KeyStorage);
llvm::yaml::Node *Value = NextKeyValue.getValue();
if (!Value)
return false;
if (KeyValue == "jsonrpc") {
// This should be "2.0". Always.
Version = dyn_cast<llvm::yaml::ScalarNode>(Value);
if (!Version || Version->getRawValue() != "\"2.0\"")
return false;
} else if (KeyValue == "method") {
Method = dyn_cast<llvm::yaml::ScalarNode>(Value);
} else if (KeyValue == "id") {
Id = dyn_cast<llvm::yaml::ScalarNode>(Value);
} else if (KeyValue == "params") {
if (!Method)
return false;
// We have to interleave the call of the function here, otherwise the
// YAMLParser will die because it can't go backwards. This is unfortunate
// because it will break clients that put the id after params. A possible
// fix would be to split the parsing and execution phases.
Params = dyn_cast<llvm::yaml::MappingNode>(Value);
callHandler(Handlers, Method, Id, Params, UnknownHandler.get());
return true;
} else {
return false;
}
}
// In case there was a request with no params, call the handler on the
// leftovers.
if (!Method)
return false;
callHandler(Handlers, Method, Id, nullptr, UnknownHandler.get());
return true;
}
void clangd::runLanguageServerLoop(std::istream &In, JSONOutput &Out,
JSONRPCDispatcher &Dispatcher,
bool &IsDone) {
while (In.good()) {
// A Language Server Protocol message starts with a HTTP header, delimited
// by \r\n.
std::string Line;
std::getline(In, Line);
if (!In.good() && errno == EINTR) {
In.clear();
continue;
}
// Skip empty lines.
llvm::StringRef LineRef(Line);
if (LineRef.trim().empty())
continue;
// We allow YAML-style comments. Technically this isn't part of the
// LSP specification, but makes writing tests easier.
if (LineRef.startswith("#"))
continue;
unsigned long long Len = 0;
// FIXME: Content-Type is a specified header, but does nothing.
// Content-Length is a mandatory header. It specifies the length of the
// following JSON.
if (LineRef.consume_front("Content-Length: "))
llvm::getAsUnsignedInteger(LineRef.trim(), 0, Len);
// Check if the next line only contains \r\n. If not this is another header,
// which we ignore.
char NewlineBuf[2];
In.read(NewlineBuf, 2);
if (std::memcmp(NewlineBuf, "\r\n", 2) != 0)
continue;
// Now read the JSON. Insert a trailing null byte as required by the YAML
// parser.
std::vector<char> JSON(Len + 1, '\0');
In.read(JSON.data(), Len);
if (Len > 0) {
llvm::StringRef JSONRef(JSON.data(), Len);
// Log the message.
Out.log("<-- " + JSONRef + "\n");
// Finally, execute the action for this JSON message.
if (!Dispatcher.call(JSONRef))
Out.log("JSON dispatch failed!\n");
// If we're done, exit the loop.
if (IsDone)
break;
}
}
}
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