clang-tools-extra/clangd/PathMapping.cpp

   1 //===--- PathMapping.cpp - apply path mappings to LSP messages -===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 #include "PathMapping.h"
   9 #include "Transport.h"
  10 #include "URI.h"
  11 #include "support/Logger.h"
  12 #include "llvm/Support/Error.h"
  13 #include "llvm/Support/Path.h"
  14 #include <algorithm>
  15 #include <optional>
  16 #include <tuple>
  17
  18 namespace clang {
  19 namespace clangd {
  20 std::optional<std::string> doPathMapping(llvm::StringRef S,
  21                                          PathMapping::Direction Dir,
  22                                          const PathMappings &Mappings) {
  23   // Return early to optimize for the common case, wherein S is not a file URI
  24   if (!S.starts_with("file://"))
  25     return std::nullopt;
  26   auto Uri = URI::parse(S);
  27   if (!Uri) {
  28     llvm::consumeError(Uri.takeError());
  29     return std::nullopt;
  30   }
  31   for (const auto &Mapping : Mappings) {
  32     const std::string &From = Dir == PathMapping::Direction::ClientToServer
  33                                   ? Mapping.ClientPath
  34                                   : Mapping.ServerPath;
  35     const std::string &To = Dir == PathMapping::Direction::ClientToServer
  36                                 ? Mapping.ServerPath
  37                                 : Mapping.ClientPath;
  38     llvm::StringRef Body = Uri->body();
  39     if (Body.consume_front(From) && (Body.empty() || Body.front() == '/')) {
  40       std::string MappedBody = (To + Body).str();
  41       return URI(Uri->scheme(), Uri->authority(), MappedBody)
  42           .toString();
  43     }
  44   }
  45   return std::nullopt;
  46 }
  47
  48 void applyPathMappings(llvm::json::Value &V, PathMapping::Direction Dir,
  49                        const PathMappings &Mappings) {
  50   using Kind = llvm::json::Value::Kind;
  51   Kind K = V.kind();
  52   if (K == Kind::Object) {
  53     llvm::json::Object *Obj = V.getAsObject();
  54     llvm::json::Object MappedObj;
  55     // 1. Map all the Keys
  56     for (auto &KV : *Obj) {
  57       if (std::optional<std::string> MappedKey =
  58               doPathMapping(KV.first.str(), Dir, Mappings)) {
  59         MappedObj.try_emplace(std::move(*MappedKey), std::move(KV.second));
  60       } else {
  61         MappedObj.try_emplace(std::move(KV.first), std::move(KV.second));
  62       }
  63     }
  64     *Obj = std::move(MappedObj);
  65     // 2. Map all the values
  66     for (auto &KV : *Obj)
  67       applyPathMappings(KV.second, Dir, Mappings);
  68   } else if (K == Kind::Array) {
  69     for (llvm::json::Value &Val : *V.getAsArray())
  70       applyPathMappings(Val, Dir, Mappings);
  71   } else if (K == Kind::String) {
  72     if (std::optional<std::string> Mapped =
  73             doPathMapping(*V.getAsString(), Dir, Mappings))
  74       V = std::move(*Mapped);
  75   }
  76 }
  77
  78 namespace {
  79
  80 class PathMappingMessageHandler : public Transport::MessageHandler {
  81 public:
  82   PathMappingMessageHandler(MessageHandler &Handler,
  83                             const PathMappings &Mappings)
  84       : WrappedHandler(Handler), Mappings(Mappings) {}
  85
  86   bool onNotify(llvm::StringRef Method, llvm::json::Value Params) override {
  87     applyPathMappings(Params, PathMapping::Direction::ClientToServer, Mappings);
  88     return WrappedHandler.onNotify(Method, std::move(Params));
  89   }
  90
  91   bool onCall(llvm::StringRef Method, llvm::json::Value Params,
  92               llvm::json::Value ID) override {
  93     applyPathMappings(Params, PathMapping::Direction::ClientToServer, Mappings);
  94     return WrappedHandler.onCall(Method, std::move(Params), std::move(ID));
  95   }
  96
  97   bool onReply(llvm::json::Value ID,
  98                llvm::Expected<llvm::json::Value> Result) override {
  99     if (Result)
 100       applyPathMappings(*Result, PathMapping::Direction::ClientToServer,
 101                         Mappings);
 102     return WrappedHandler.onReply(std::move(ID), std::move(Result));
 103   }
 104
 105 private:
 106   Transport::MessageHandler &WrappedHandler;
 107   const PathMappings &Mappings;
 108 };
 109
 110 // Apply path mappings to all LSP messages by intercepting all params/results
 111 // and then delegating to the normal transport
 112 class PathMappingTransport : public Transport {
 113 public:
 114   PathMappingTransport(std::unique_ptr<Transport> Transp, PathMappings Mappings)
 115       : WrappedTransport(std::move(Transp)), Mappings(std::move(Mappings)) {}
 116
 117   void notify(llvm::StringRef Method, llvm::json::Value Params) override {
 118     applyPathMappings(Params, PathMapping::Direction::ServerToClient, Mappings);
 119     WrappedTransport->notify(Method, std::move(Params));
 120   }
 121
 122   void call(llvm::StringRef Method, llvm::json::Value Params,
 123             llvm::json::Value ID) override {
 124     applyPathMappings(Params, PathMapping::Direction::ServerToClient, Mappings);
 125     WrappedTransport->call(Method, std::move(Params), std::move(ID));
 126   }
 127
 128   void reply(llvm::json::Value ID,
 129              llvm::Expected<llvm::json::Value> Result) override {
 130     if (Result)
 131       applyPathMappings(*Result, PathMapping::Direction::ServerToClient,
 132                         Mappings);
 133     WrappedTransport->reply(std::move(ID), std::move(Result));
 134   }
 135
 136   llvm::Error loop(MessageHandler &Handler) override {
 137     PathMappingMessageHandler WrappedHandler(Handler, Mappings);
 138     return WrappedTransport->loop(WrappedHandler);
 139   }
 140
 141 private:
 142   std::unique_ptr<Transport> WrappedTransport;
 143   PathMappings Mappings;
 144 };
 145
 146 // Converts a unix/windows path to the path portion of a file URI
 147 // e.g. "C:\foo" -> "/C:/foo"
 148 llvm::Expected<std::string> parsePath(llvm::StringRef Path) {
 149   namespace path = llvm::sys::path;
 150   if (path::is_absolute(Path, path::Style::posix)) {
 151     return std::string(Path);
 152   }
 153   if (path::is_absolute(Path, path::Style::windows)) {
 154     std::string Converted = path::convert_to_slash(Path, path::Style::windows);
 155     if (Converted.front() != '/')
 156       Converted = "/" + Converted;
 157     return Converted;
 158   }
 159   return error("Path not absolute: {0}", Path);
 160 }
 161
 162 } // namespace
 163
 164 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const PathMapping &M) {
 165   return OS << M.ClientPath << "=" << M.ServerPath;
 166 }
 167
 168 llvm::Expected<PathMappings>
 169 parsePathMappings(llvm::StringRef RawPathMappings) {
 170   llvm::StringRef ClientPath, ServerPath, PathPair, Rest = RawPathMappings;
 171   PathMappings ParsedMappings;
 172   while (!Rest.empty()) {
 173     std::tie(PathPair, Rest) = Rest.split(",");
 174     std::tie(ClientPath, ServerPath) = PathPair.split("=");
 175     if (ClientPath.empty() || ServerPath.empty())
 176       return error("Not a valid path mapping pair: {0}", PathPair);
 177     llvm::Expected<std::string> ParsedClientPath = parsePath(ClientPath);
 178     if (!ParsedClientPath)
 179       return ParsedClientPath.takeError();
 180     llvm::Expected<std::string> ParsedServerPath = parsePath(ServerPath);
 181     if (!ParsedServerPath)
 182       return ParsedServerPath.takeError();
 183     ParsedMappings.push_back(
 184         {std::move(*ParsedClientPath), std::move(*ParsedServerPath)});
 185   }
 186   return ParsedMappings;
 187 }
 188
 189 std::unique_ptr<Transport>
 190 createPathMappingTransport(std::unique_ptr<Transport> Transp,
 191                            PathMappings Mappings) {
 192   return std::make_unique<PathMappingTransport>(std::move(Transp), Mappings);
 193 }
 194
 195 } // namespace clangd
 196 } // namespace clang