clang-tools  8.0.0
JSONTransport.cpp
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1 //===--- JSONTransport.cpp - sending and receiving LSP messages over JSON -===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 #include "Logger.h"
10 #include "Protocol.h" // For LSPError
11 #include "Transport.h"
12 #include "llvm/Support/Errno.h"
13 
14 namespace clang {
15 namespace clangd {
16 namespace {
17 
18 llvm::json::Object encodeError(llvm::Error E) {
19  std::string Message;
21  if (llvm::Error Unhandled = llvm::handleErrors(
22  std::move(E), [&](const LSPError &L) -> llvm::Error {
23  Message = L.Message;
24  Code = L.Code;
25  return llvm::Error::success();
26  }))
27  Message = llvm::toString(std::move(Unhandled));
28 
29  return llvm::json::Object{
30  {"message", std::move(Message)},
31  {"code", int64_t(Code)},
32  };
33 }
34 
35 llvm::Error decodeError(const llvm::json::Object &O) {
36  std::string Msg = O.getString("message").getValueOr("Unspecified error");
37  if (auto Code = O.getInteger("code"))
38  return llvm::make_error<LSPError>(std::move(Msg), ErrorCode(*Code));
39  return llvm::make_error<llvm::StringError>(std::move(Msg),
40  llvm::inconvertibleErrorCode());
41 }
42 
43 class JSONTransport : public Transport {
44 public:
45  JSONTransport(std::FILE *In, llvm::raw_ostream &Out,
46  llvm::raw_ostream *InMirror, bool Pretty, JSONStreamStyle Style)
47  : In(In), Out(Out), InMirror(InMirror ? *InMirror : llvm::nulls()),
48  Pretty(Pretty), Style(Style) {}
49 
50  void notify(llvm::StringRef Method, llvm::json::Value Params) override {
51  sendMessage(llvm::json::Object{
52  {"jsonrpc", "2.0"},
53  {"method", Method},
54  {"params", std::move(Params)},
55  });
56  }
57  void call(llvm::StringRef Method, llvm::json::Value Params,
58  llvm::json::Value ID) override {
59  sendMessage(llvm::json::Object{
60  {"jsonrpc", "2.0"},
61  {"id", std::move(ID)},
62  {"method", Method},
63  {"params", std::move(Params)},
64  });
65  }
66  void reply(llvm::json::Value ID,
67  llvm::Expected<llvm::json::Value> Result) override {
68  if (Result) {
69  sendMessage(llvm::json::Object{
70  {"jsonrpc", "2.0"},
71  {"id", std::move(ID)},
72  {"result", std::move(*Result)},
73  });
74  } else {
75  sendMessage(llvm::json::Object{
76  {"jsonrpc", "2.0"},
77  {"id", std::move(ID)},
78  {"error", encodeError(Result.takeError())},
79  });
80  }
81  }
82 
83  llvm::Error loop(MessageHandler &Handler) override {
84  while (!feof(In)) {
85  if (ferror(In))
86  return llvm::errorCodeToError(
87  std::error_code(errno, std::system_category()));
88  if (auto JSON = readRawMessage()) {
89  if (auto Doc = llvm::json::parse(*JSON)) {
90  vlog(Pretty ? "<<< {0:2}\n" : "<<< {0}\n", *Doc);
91  if (!handleMessage(std::move(*Doc), Handler))
92  return llvm::Error::success(); // we saw the "exit" notification.
93  } else {
94  // Parse error. Log the raw message.
95  vlog("<<< {0}\n", *JSON);
96  elog("JSON parse error: {0}", llvm::toString(Doc.takeError()));
97  }
98  }
99  }
100  return llvm::errorCodeToError(std::make_error_code(std::errc::io_error));
101  }
102 
103 private:
104  // Dispatches incoming message to Handler onNotify/onCall/onReply.
105  bool handleMessage(llvm::json::Value Message, MessageHandler &Handler);
106  // Writes outgoing message to Out stream.
107  void sendMessage(llvm::json::Value Message) {
108  std::string S;
109  llvm::raw_string_ostream OS(S);
110  OS << llvm::formatv(Pretty ? "{0:2}" : "{0}", Message);
111  OS.flush();
112  Out << "Content-Length: " << S.size() << "\r\n\r\n" << S;
113  Out.flush();
114  vlog(">>> {0}\n", S);
115  }
116 
117  // Read raw string messages from input stream.
118  llvm::Optional<std::string> readRawMessage() {
119  return Style == JSONStreamStyle::Delimited ? readDelimitedMessage()
120  : readStandardMessage();
121  }
122  llvm::Optional<std::string> readDelimitedMessage();
123  llvm::Optional<std::string> readStandardMessage();
124 
125  std::FILE *In;
126  llvm::raw_ostream &Out;
127  llvm::raw_ostream &InMirror;
128  bool Pretty;
129  JSONStreamStyle Style;
130 };
131 
132 bool JSONTransport::handleMessage(llvm::json::Value Message,
133  MessageHandler &Handler) {
134  // Message must be an object with "jsonrpc":"2.0".
135  auto *Object = Message.getAsObject();
136  if (!Object ||
137  Object->getString("jsonrpc") != llvm::Optional<llvm::StringRef>("2.0")) {
138  elog("Not a JSON-RPC 2.0 message: {0:2}", Message);
139  return false;
140  }
141  // ID may be any JSON value. If absent, this is a notification.
142  llvm::Optional<llvm::json::Value> ID;
143  if (auto *I = Object->get("id"))
144  ID = std::move(*I);
145  auto Method = Object->getString("method");
146  if (!Method) { // This is a response.
147  if (!ID) {
148  elog("No method and no response ID: {0:2}", Message);
149  return false;
150  }
151  if (auto *Err = Object->getObject("error"))
152  return Handler.onReply(std::move(*ID), decodeError(*Err));
153  // Result should be given, use null if not.
154  llvm::json::Value Result = nullptr;
155  if (auto *R = Object->get("result"))
156  Result = std::move(*R);
157  return Handler.onReply(std::move(*ID), std::move(Result));
158  }
159  // Params should be given, use null if not.
160  llvm::json::Value Params = nullptr;
161  if (auto *P = Object->get("params"))
162  Params = std::move(*P);
163 
164  if (ID)
165  return Handler.onCall(*Method, std::move(Params), std::move(*ID));
166  else
167  return Handler.onNotify(*Method, std::move(Params));
168 }
169 
170 // Tries to read a line up to and including \n.
171 // If failing, feof() or ferror() will be set.
172 bool readLine(std::FILE *In, std::string &Out) {
173  static constexpr int BufSize = 1024;
174  size_t Size = 0;
175  Out.clear();
176  for (;;) {
177  Out.resize(Size + BufSize);
178  // Handle EINTR which is sent when a debugger attaches on some platforms.
179  if (!llvm::sys::RetryAfterSignal(nullptr, ::fgets, &Out[Size], BufSize, In))
180  return false;
181  clearerr(In);
182  // If the line contained null bytes, anything after it (including \n) will
183  // be ignored. Fortunately this is not a legal header or JSON.
184  size_t Read = std::strlen(&Out[Size]);
185  if (Read > 0 && Out[Size + Read - 1] == '\n') {
186  Out.resize(Size + Read);
187  return true;
188  }
189  Size += Read;
190  }
191 }
192 
193 // Returns None when:
194 // - ferror() or feof() are set.
195 // - Content-Length is missing or empty (protocol error)
196 llvm::Optional<std::string> JSONTransport::readStandardMessage() {
197  // A Language Server Protocol message starts with a set of HTTP headers,
198  // delimited by \r\n, and terminated by an empty line (\r\n).
199  unsigned long long ContentLength = 0;
200  std::string Line;
201  while (true) {
202  if (feof(In) || ferror(In) || !readLine(In, Line))
203  return llvm::None;
204  InMirror << Line;
205 
206  llvm::StringRef LineRef(Line);
207 
208  // We allow comments in headers. Technically this isn't part
209 
210  // of the LSP specification, but makes writing tests easier.
211  if (LineRef.startswith("#"))
212  continue;
213 
214  // Content-Length is a mandatory header, and the only one we handle.
215  if (LineRef.consume_front("Content-Length: ")) {
216  if (ContentLength != 0) {
217  elog("Warning: Duplicate Content-Length header received. "
218  "The previous value for this message ({0}) was ignored.",
219  ContentLength);
220  }
221  llvm::getAsUnsignedInteger(LineRef.trim(), 0, ContentLength);
222  continue;
223  } else if (!LineRef.trim().empty()) {
224  // It's another header, ignore it.
225  continue;
226  } else {
227  // An empty line indicates the end of headers.
228  // Go ahead and read the JSON.
229  break;
230  }
231  }
232 
233  // The fuzzer likes crashing us by sending "Content-Length: 9999999999999999"
234  if (ContentLength > 1 << 30) { // 1024M
235  elog("Refusing to read message with long Content-Length: {0}. "
236  "Expect protocol errors",
237  ContentLength);
238  return llvm::None;
239  }
240  if (ContentLength == 0) {
241  log("Warning: Missing Content-Length header, or zero-length message.");
242  return llvm::None;
243  }
244 
245  std::string JSON(ContentLength, '\0');
246  for (size_t Pos = 0, Read; Pos < ContentLength; Pos += Read) {
247  // Handle EINTR which is sent when a debugger attaches on some platforms.
248  Read = llvm::sys::RetryAfterSignal(0u, ::fread, &JSON[Pos], 1,
249  ContentLength - Pos, In);
250  if (Read == 0) {
251  elog("Input was aborted. Read only {0} bytes of expected {1}.", Pos,
252  ContentLength);
253  return llvm::None;
254  }
255  InMirror << llvm::StringRef(&JSON[Pos], Read);
256  clearerr(In); // If we're done, the error was transient. If we're not done,
257  // either it was transient or we'll see it again on retry.
258  Pos += Read;
259  }
260  return std::move(JSON);
261 }
262 
263 // For lit tests we support a simplified syntax:
264 // - messages are delimited by '---' on a line by itself
265 // - lines starting with # are ignored.
266 // This is a testing path, so favor simplicity over performance here.
267 // When returning None, feof() or ferror() will be set.
268 llvm::Optional<std::string> JSONTransport::readDelimitedMessage() {
269  std::string JSON;
270  std::string Line;
271  while (readLine(In, Line)) {
272  InMirror << Line;
273  auto LineRef = llvm::StringRef(Line).trim();
274  if (LineRef.startswith("#")) // comment
275  continue;
276 
277  // found a delimiter
278  if (LineRef.rtrim() == "---")
279  break;
280 
281  JSON += Line;
282  }
283 
284  if (ferror(In)) {
285  elog("Input error while reading message!");
286  return llvm::None;
287  }
288  return std::move(JSON); // Including at EOF
289 }
290 
291 } // namespace
292 
293 std::unique_ptr<Transport> newJSONTransport(std::FILE *In,
294  llvm::raw_ostream &Out,
295  llvm::raw_ostream *InMirror,
296  bool Pretty,
297  JSONStreamStyle Style) {
298  return llvm::make_unique<JSONTransport>(In, Out, InMirror, Pretty, Style);
299 }
300 
301 } // namespace clangd
302 } // namespace clang
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static llvm::StringRef toString(SpecialMemberFunctionsCheck::SpecialMemberFunctionKind K)
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void vlog(const char *Fmt, Ts &&... Vals)
Definition: Logger.h:68
void elog(const char *Fmt, Ts &&... Vals)
Definition: Logger.h:57
void handleErrors(llvm::ArrayRef< ClangTidyError > Errors, ClangTidyContext &Context, bool Fix, unsigned &WarningsAsErrorsCount, llvm::IntrusiveRefCntPtr< llvm::vfs::FileSystem > BaseFS)
Displays the found Errors to the users.
Definition: ClangTidy.cpp:581
void log(const char *Fmt, Ts &&... Vals)
Definition: Logger.h:63
std::unique_ptr< Transport > newJSONTransport(std::FILE *In, llvm::raw_ostream &Out, llvm::raw_ostream *InMirror, bool Pretty, JSONStreamStyle Style)
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
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===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//