clang-tools  8.0.0
ClangdServer.h
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1 //===--- ClangdServer.h - Main clangd server code ----------------*- C++-*-===//
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 
10 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_CLANGDSERVER_H
11 #define LLVM_CLANG_TOOLS_EXTRA_CLANGD_CLANGDSERVER_H
12 
13 #include "Cancellation.h"
14 #include "ClangdUnit.h"
15 #include "CodeComplete.h"
16 #include "FSProvider.h"
17 #include "Function.h"
19 #include "Protocol.h"
20 #include "TUScheduler.h"
21 #include "index/Background.h"
22 #include "index/FileIndex.h"
23 #include "index/Index.h"
24 #include "clang/Tooling/CompilationDatabase.h"
25 #include "clang/Tooling/Core/Replacement.h"
26 #include "llvm/ADT/IntrusiveRefCntPtr.h"
27 #include "llvm/ADT/Optional.h"
28 #include "llvm/ADT/StringRef.h"
29 #include <functional>
30 #include <future>
31 #include <string>
32 #include <type_traits>
33 #include <utility>
34 
35 namespace clang {
36 class PCHContainerOperations;
37 
38 namespace clangd {
39 
40 // FIXME: find a better name.
42 public:
43  virtual ~DiagnosticsConsumer() = default;
44 
45  /// Called by ClangdServer when \p Diagnostics for \p File are ready.
46  virtual void onDiagnosticsReady(PathRef File,
47  std::vector<Diag> Diagnostics) = 0;
48  /// Called whenever the file status is updated.
49  virtual void onFileUpdated(PathRef File, const TUStatus &Status){};
50 };
51 
52 /// Manages a collection of source files and derived data (ASTs, indexes),
53 /// and provides language-aware features such as code completion.
54 ///
55 /// The primary client is ClangdLSPServer which exposes these features via
56 /// the Language Server protocol. ClangdServer may also be embedded directly,
57 /// though its API is not stable over time.
58 ///
59 /// ClangdServer should be used from a single thread. Many potentially-slow
60 /// operations have asynchronous APIs and deliver their results on another
61 /// thread.
62 /// Such operations support cancellation: if the caller sets up a cancelable
63 /// context, many operations will notice cancellation and fail early.
64 /// (ClangdLSPServer uses this to implement $/cancelRequest).
65 class ClangdServer {
66 public:
67  struct Options {
68  /// To process requests asynchronously, ClangdServer spawns worker threads.
69  /// If this is zero, no threads are spawned. All work is done on the calling
70  /// thread, and callbacks are invoked before "async" functions return.
71  unsigned AsyncThreadsCount = getDefaultAsyncThreadsCount();
72 
73  /// AST caching policy. The default is to keep up to 3 ASTs in memory.
75 
76  /// Cached preambles are potentially large. If false, store them on disk.
77  bool StorePreamblesInMemory = true;
78 
79  /// If true, ClangdServer builds a dynamic in-memory index for symbols in
80  /// opened files and uses the index to augment code completion results.
81  bool BuildDynamicSymbolIndex = false;
82  /// Use a heavier and faster in-memory index implementation.
83  /// FIXME: we should make this true if it isn't too slow to build!.
84  bool HeavyweightDynamicSymbolIndex = false;
85  /// If true, ClangdServer automatically indexes files in the current project
86  /// on background threads. The index is stored in the project root.
87  bool BackgroundIndex = false;
88  /// If set to non-zero, the background index rebuilds the symbol index
89  /// periodically every BuildIndexPeriodMs milliseconds; otherwise, the
90  /// symbol index will be updated for each indexed file.
91  size_t BackgroundIndexRebuildPeriodMs = 0;
92 
93  /// If set, use this index to augment code completion results.
94  SymbolIndex *StaticIndex = nullptr;
95 
96  /// Clangd's workspace root. Relevant for "workspace" operations not bound
97  /// to a particular file.
98  /// FIXME: If not set, should use the current working directory.
99  llvm::Optional<std::string> WorkspaceRoot;
100 
101  /// The resource directory is used to find internal headers, overriding
102  /// defaults and -resource-dir compiler flag).
103  /// If None, ClangdServer calls CompilerInvocation::GetResourcePath() to
104  /// obtain the standard resource directory.
105  llvm::Optional<std::string> ResourceDir = llvm::None;
106 
107  /// Time to wait after a new file version before computing diagnostics.
108  std::chrono::steady_clock::duration UpdateDebounce =
109  std::chrono::milliseconds(500);
110  };
111  // Sensible default options for use in tests.
112  // Features like indexing must be enabled if desired.
113  static Options optsForTest();
114 
115  /// Creates a new ClangdServer instance.
116  ///
117  /// ClangdServer uses \p CDB to obtain compilation arguments for parsing. Note
118  /// that ClangdServer only obtains compilation arguments once for each newly
119  /// added file (i.e., when processing a first call to addDocument) and reuses
120  /// those arguments for subsequent reparses. However, ClangdServer will check
121  /// if compilation arguments changed on calls to forceReparse().
122  ///
123  /// After each parsing request finishes, ClangdServer reports diagnostics to
124  /// \p DiagConsumer. Note that a callback to \p DiagConsumer happens on a
125  /// worker thread. Therefore, instances of \p DiagConsumer must properly
126  /// synchronize access to shared state.
128  const FileSystemProvider &FSProvider,
129  DiagnosticsConsumer &DiagConsumer, const Options &Opts);
130 
131  /// Add a \p File to the list of tracked C++ files or update the contents if
132  /// \p File is already tracked. Also schedules parsing of the AST for it on a
133  /// separate thread. When the parsing is complete, DiagConsumer passed in
134  /// constructor will receive onDiagnosticsReady callback.
135  void addDocument(PathRef File, StringRef Contents,
137 
138  /// Remove \p File from list of tracked files, schedule a request to free
139  /// resources associated with it. Pending diagnostics for closed files may not
140  /// be delivered, even if requested with WantDiags::Auto or WantDiags::Yes.
141  void removeDocument(PathRef File);
142 
143  /// Run code completion for \p File at \p Pos.
144  /// Request is processed asynchronously.
145  ///
146  /// This method should only be called for currently tracked files. However, it
147  /// is safe to call removeDocument for \p File after this method returns, even
148  /// while returned future is not yet ready.
149  /// A version of `codeComplete` that runs \p Callback on the processing thread
150  /// when codeComplete results become available.
152  const clangd::CodeCompleteOptions &Opts,
154 
155  /// Provide signature help for \p File at \p Pos. This method should only be
156  /// called for tracked files.
158 
159  /// Get definition of symbol at a specified \p Line and \p Column in \p File.
161  Callback<std::vector<Location>> CB);
162 
163  /// Helper function that returns a path to the corresponding source file when
164  /// given a header file and vice versa.
165  llvm::Optional<Path> switchSourceHeader(PathRef Path);
166 
167  /// Get document highlights for a given position.
169  Callback<std::vector<DocumentHighlight>> CB);
170 
171  /// Get code hover for a given position.
172  void findHover(PathRef File, Position Pos,
173  Callback<llvm::Optional<Hover>> CB);
174 
175  /// Retrieve the top symbols from the workspace matching a query.
176  void workspaceSymbols(StringRef Query, int Limit,
177  Callback<std::vector<SymbolInformation>> CB);
178 
179  /// Retrieve the symbols within the specified file.
180  void documentSymbols(StringRef File,
181  Callback<std::vector<DocumentSymbol>> CB);
182 
183  /// Retrieve locations for symbol references.
184  void findReferences(PathRef File, Position Pos, uint32_t Limit,
185  Callback<std::vector<Location>> CB);
186 
187  /// Run formatting for \p Rng inside \p File with content \p Code.
188  llvm::Expected<tooling::Replacements> formatRange(StringRef Code,
189  PathRef File, Range Rng);
190 
191  /// Run formatting for the whole \p File with content \p Code.
192  llvm::Expected<tooling::Replacements> formatFile(StringRef Code,
193  PathRef File);
194 
195  /// Run formatting after a character was typed at \p Pos in \p File with
196  /// content \p Code.
197  llvm::Expected<tooling::Replacements>
198  formatOnType(StringRef Code, PathRef File, Position Pos);
199 
200  /// Rename all occurrences of the symbol at the \p Pos in \p File to
201  /// \p NewName.
202  void rename(PathRef File, Position Pos, llvm::StringRef NewName,
203  Callback<std::vector<tooling::Replacement>> CB);
204 
205  /// Only for testing purposes.
206  /// Waits until all requests to worker thread are finished and dumps AST for
207  /// \p File. \p File must be in the list of added documents.
208  void dumpAST(PathRef File, llvm::unique_function<void(std::string)> Callback);
209  /// Called when an event occurs for a watched file in the workspace.
210  void onFileEvent(const DidChangeWatchedFilesParams &Params);
211 
212  /// Get symbol info for given position.
213  /// Clangd extension - not part of official LSP.
214  void symbolInfo(PathRef File, Position Pos,
215  Callback<std::vector<SymbolDetails>> CB);
216 
217  /// Returns estimated memory usage for each of the currently open files.
218  /// The order of results is unspecified.
219  /// Overall memory usage of clangd may be significantly more than reported
220  /// here, as this metric does not account (at least) for:
221  /// - memory occupied by static and dynamic index,
222  /// - memory required for in-flight requests,
223  /// FIXME: those metrics might be useful too, we should add them.
224  std::vector<std::pair<Path, std::size_t>> getUsedBytesPerFile() const;
225 
226  /// Returns the active dynamic index if one was built.
227  /// This can be useful for testing, debugging, or observing memory usage.
228  const SymbolIndex *dynamicIndex() const { return DynamicIdx.get(); }
229 
230  // Blocks the main thread until the server is idle. Only for use in tests.
231  // Returns false if the timeout expires.
232  LLVM_NODISCARD bool
233  blockUntilIdleForTest(llvm::Optional<double> TimeoutSeconds = 10);
234 
235 private:
236  /// FIXME: This stats several files to find a .clang-format file. I/O can be
237  /// slow. Think of a way to cache this.
238  llvm::Expected<tooling::Replacements>
239  formatCode(llvm::StringRef Code, PathRef File,
240  ArrayRef<tooling::Range> Ranges);
241 
242  tooling::CompileCommand getCompileCommand(PathRef File);
243 
244  const GlobalCompilationDatabase &CDB;
245  const FileSystemProvider &FSProvider;
246 
248  // The index used to look up symbols. This could be:
249  // - null (all index functionality is optional)
250  // - the dynamic index owned by ClangdServer (DynamicIdx)
251  // - the static index passed to the constructor
252  // - a merged view of a static and dynamic index (MergedIndex)
253  const SymbolIndex *Index = nullptr;
254  // If present, an index of symbols in open files. Read via *Index.
255  std::unique_ptr<FileIndex> DynamicIdx;
256  // If present, the new "auto-index" maintained in background threads.
257  std::unique_ptr<BackgroundIndex> BackgroundIdx;
258  // Storage for merged views of the various indexes.
259  std::vector<std::unique_ptr<SymbolIndex>> MergedIdx;
260 
261  // GUARDED_BY(CachedCompletionFuzzyFindRequestMutex)
262  llvm::StringMap<llvm::Optional<FuzzyFindRequest>>
263  CachedCompletionFuzzyFindRequestByFile;
264  mutable std::mutex CachedCompletionFuzzyFindRequestMutex;
265 
266  llvm::Optional<std::string> WorkspaceRoot;
267  std::shared_ptr<PCHContainerOperations> PCHs;
268  // WorkScheduler has to be the last member, because its destructor has to be
269  // called before all other members to stop the worker thread that references
270  // ClangdServer.
271  TUScheduler WorkScheduler;
272 };
273 
274 } // namespace clangd
275 } // namespace clang
276 
277 #endif
SignatureHelp signatureHelp(PathRef FileName, const tooling::CompileCommand &Command, const PreambleData *Preamble, llvm::StringRef Contents, Position Pos, llvm::IntrusiveRefCntPtr< llvm::vfs::FileSystem > VFS, std::shared_ptr< PCHContainerOperations > PCHs, const SymbolIndex *Index)
WantDiagnostics
Determines whether diagnostics should be generated for a file snapshot.
Definition: TUScheduler.h:39
std::vector< Location > findDefinitions(ParsedAST &AST, Position Pos, const SymbolIndex *Index)
Get definition of symbol at a specified Pos.
Definition: XRefs.cpp:244
CodeCompleteResult codeComplete(PathRef FileName, const tooling::CompileCommand &Command, const PreambleData *Preamble, llvm::StringRef Contents, Position Pos, llvm::IntrusiveRefCntPtr< llvm::vfs::FileSystem > VFS, std::shared_ptr< PCHContainerOperations > PCHs, CodeCompleteOptions Opts, SpeculativeFuzzyFind *SpecFuzzyFind)
const SymbolIndex * dynamicIndex() const
Returns the active dynamic index if one was built.
Definition: ClangdServer.h:228
llvm::StringRef Contents
void dumpAST(ParsedAST &AST, llvm::raw_ostream &OS)
For testing/debugging purposes.
Definition: ClangdUnit.cpp:222
Interface for symbol indexes that can be used for searching or matching symbols among a set of symbol...
Definition: Index.h:487
llvm::StringRef PathRef
A typedef to represent a ref to file path.
Definition: Path.h:24
llvm::unique_function< void(llvm::Expected< T >)> Callback
A Callback<T> is a void function that accepts Expected<T>.
Definition: Function.h:29
Documents should not be synced at all.
ASTRetentionPolicy RetentionPolicy
AST caching policy. The default is to keep up to 3 ASTs in memory.
Definition: ClangdServer.h:74
Configuration of the AST retention policy.
Definition: TUScheduler.h:49
Provides compilation arguments used for parsing C and C++ files.
std::string Path
A typedef to represent a file path.
Definition: Path.h:21
virtual void onDiagnosticsReady(PathRef File, std::vector< Diag > Diagnostics)=0
Called by ClangdServer when Diagnostics for File are ready.
virtual ~DiagnosticsConsumer()=default
std::vector< DocumentHighlight > findDocumentHighlights(ParsedAST &AST, Position Pos)
Returns highlights for all usages of a symbol at Pos.
Definition: XRefs.cpp:434
static llvm::cl::opt< Path > ResourceDir("resource-dir", llvm::cl::desc("Directory for system clang headers"), llvm::cl::init(""), llvm::cl::Hidden)
Position Pos
llvm::Optional< std::string > WorkspaceRoot
Clangd&#39;s workspace root.
Definition: ClangdServer.h:99
unsigned getDefaultAsyncThreadsCount()
Returns a number of a default async threads to use for TUScheduler.
std::vector< Location > findReferences(ParsedAST &AST, Position Pos, uint32_t Limit, const SymbolIndex *Index)
Returns reference locations of the symbol at a specified Pos.
Definition: XRefs.cpp:706
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
std::shared_ptr< PCHContainerOperations > PCHs
Manages a collection of source files and derived data (ASTs, indexes), and provides language-aware fe...
Definition: ClangdServer.h:65
Handles running tasks for ClangdServer and managing the resources (e.g., preambles and ASTs) for open...
Definition: TUScheduler.h:122
Diagnostics must not be generated for this snapshot.
virtual void onFileUpdated(PathRef File, const TUStatus &Status)
Called whenever the file status is updated.
Definition: ClangdServer.h:49
const SymbolIndex * Index
Definition: Dexp.cpp:85