1//===--- SourceCode.h - Manipulating source code as strings -----*- C++ -*-===//
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//
9// Various code that examines C++ source code without using heavy AST machinery
10// (and often not even the lexer). To be used sparingly!
11//
12//===----------------------------------------------------------------------===//
13#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_SOURCECODE_H
14#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_SOURCECODE_H
15
16#include "Protocol.h"
17#include "support/Context.h"
18#include "support/ThreadsafeFS.h"
19#include "clang/Basic/CharInfo.h"
20#include "clang/Basic/Diagnostic.h"
21#include "clang/Basic/LangOptions.h"
22#include "clang/Basic/SourceLocation.h"
23#include "clang/Basic/SourceManager.h"
24#include "clang/Format/Format.h"
25#include "clang/Lex/HeaderSearch.h"
26#include "clang/Tooling/Core/Replacement.h"
27#include "clang/Tooling/Syntax/Tokens.h"
28#include "llvm/ADT/StringRef.h"
29#include "llvm/ADT/StringSet.h"
30#include "llvm/Support/Error.h"
31#include <optional>
32#include <string>
33
34namespace clang {
35class SourceManager;
36
37namespace clangd {
38
39// We tend to generate digests for source codes in a lot of different places.
40// This represents the type for those digests to prevent us hard coding details
41// of hashing function at every place that needs to store this information.
42using FileDigest = std::array<uint8_t, 8>;
43FileDigest digest(StringRef Content);
44std::optional<FileDigest> digestFile(const SourceManager &SM, FileID FID);
45
46// This context variable controls the behavior of functions in this file
47// that convert between LSP offsets and native clang byte offsets.
48// If not set, defaults to UTF-16 for backwards-compatibility.
49extern Key<OffsetEncoding> kCurrentOffsetEncoding;
50
51// Counts the number of UTF-16 code units needed to represent a string (LSP
52// specifies string lengths in UTF-16 code units).
53// Use of UTF-16 may be overridden by kCurrentOffsetEncoding.
54size_t lspLength(StringRef Code);
55
56/// Turn a [line, column] pair into an offset in Code.
57///
58/// If P.character exceeds the line length, returns the offset at end-of-line.
59/// (If !AllowColumnsBeyondLineLength, then returns an error instead).
60/// If the line number is out of range, returns an error.
61///
62/// The returned value is in the range [0, Code.size()].
63llvm::Expected<size_t>
64positionToOffset(llvm::StringRef Code, Position P,
65 bool AllowColumnsBeyondLineLength = true);
66
67/// Turn an offset in Code into a [line, column] pair.
68/// The offset must be in range [0, Code.size()].
69Position offsetToPosition(llvm::StringRef Code, size_t Offset);
70
71/// Turn a SourceLocation into a [line, column] pair.
72/// FIXME: This should return an error if the location is invalid.
73Position sourceLocToPosition(const SourceManager &SM, SourceLocation Loc);
74
75/// Return the file location, corresponding to \p P. Note that one should take
76/// care to avoid comparing the result with expansion locations.
77llvm::Expected<SourceLocation> sourceLocationInMainFile(const SourceManager &SM,
78 Position P);
79
80/// Returns true iff \p Loc is inside the main file. This function handles
81/// file & macro locations. For macro locations, returns iff the macro is being
82/// expanded inside the main file.
83///
84/// The function is usually used to check whether a declaration is inside the
85/// the main file.
86bool isInsideMainFile(SourceLocation Loc, const SourceManager &SM);
87
88/// Returns the #include location through which IncludedFIle was loaded.
89/// Where SM.getIncludeLoc() returns the location of the *filename*, which may
90/// be in a macro, includeHashLoc() returns the location of the #.
91SourceLocation includeHashLoc(FileID IncludedFile, const SourceManager &SM);
92
93/// Returns true if the token at Loc is spelled in the source code.
94/// This is not the case for:
95/// * symbols formed via macro concatenation, the spelling location will
96/// be "<scratch space>"
97/// * symbols controlled and defined by a compile command-line option
98/// `-DName=foo`, the spelling location will be "<command line>".
99bool isSpelledInSource(SourceLocation Loc, const SourceManager &SM);
100
101/// Turns a token range into a half-open range and checks its correctness.
102/// The resulting range will have only valid source location on both sides, both
103/// of which are file locations.
104///
105/// File locations always point to a particular offset in a file, i.e. they
106/// never refer to a location inside a macro expansion. Turning locations from
107/// macro expansions into file locations is ambiguous - one can use
108/// SourceManager::{getExpansion|getFile|getSpelling}Loc. This function
109/// calls SourceManager::getFileLoc on both ends of \p R to do the conversion.
110///
111/// User input (e.g. cursor position) is expressed as a file location, so this
112/// function can be viewed as a way to normalize the ranges used in the clang
113/// AST so that they are comparable with ranges coming from the user input.
114std::optional<SourceRange> toHalfOpenFileRange(const SourceManager &Mgr,
115 const LangOptions &LangOpts,
116 SourceRange R);
117
118/// Returns true iff all of the following conditions hold:
119/// - start and end locations are valid,
120/// - start and end locations are file locations from the same file
121/// (i.e. expansion locations are not taken into account).
122/// - start offset <= end offset.
123/// FIXME: introduce a type for source range with this invariant.
124bool isValidFileRange(const SourceManager &Mgr, SourceRange R);
125
126/// Returns the source code covered by the source range.
127/// EXPECTS: isValidFileRange(R) == true.
128llvm::StringRef toSourceCode(const SourceManager &SM, SourceRange R);
129
130// Converts a half-open clang source range to an LSP range.
131// Note that clang also uses closed source ranges, which this can't handle!
132Range halfOpenToRange(const SourceManager &SM, CharSourceRange R);
133
134// Expand range `A` to also contain `B`.
135void unionRanges(Range &A, Range B);
136
137// Converts an offset to a clang line/column (1-based, columns are bytes).
138// The offset must be in range [0, Code.size()].
139// Prefer to use SourceManager if one is available.
140std::pair<size_t, size_t> offsetToClangLineColumn(llvm::StringRef Code,
141 size_t Offset);
142
143/// From "a::b::c", return {"a::b::", "c"}. Scope is empty if there's no
144/// qualifier.
145std::pair<llvm::StringRef, llvm::StringRef>
146splitQualifiedName(llvm::StringRef QName);
147
148TextEdit replacementToEdit(StringRef Code, const tooling::Replacement &R);
149
150std::vector<TextEdit> replacementsToEdits(StringRef Code,
151 const tooling::Replacements &Repls);
152
153TextEdit toTextEdit(const FixItHint &FixIt, const SourceManager &M,
154 const LangOptions &L);
155
156/// Get the canonical path of \p F. This means:
157///
158/// - Absolute path
159/// - Symlinks resolved
160/// - No "." or ".." component
161/// - No duplicate or trailing directory separator
162///
163/// This function should be used when paths needs to be used outside the
164/// component that generate it, so that paths are normalized as much as
165/// possible.
166std::optional<std::string> getCanonicalPath(const FileEntryRef F,
167 FileManager &FileMgr);
168
169/// Choose the clang-format style we should apply to a certain file.
170/// This will usually use FS to look for .clang-format directories.
171/// FIXME: should we be caching the .clang-format file search?
172/// This uses format::DefaultFormatStyle and format::DefaultFallbackStyle,
173/// though the latter may have been overridden in main()!
174/// \p FormatFile indicates whether the returned FormatStyle is used
175/// to format the entire main file (or a range selected by the user
176/// which can be arbitrarily long).
177format::FormatStyle getFormatStyleForFile(llvm::StringRef File,
178 llvm::StringRef Content,
179 const ThreadsafeFS &TFS,
180 bool FormatFile);
181
182/// Cleanup and format the given replacements.
183llvm::Expected<tooling::Replacements>
184cleanupAndFormat(StringRef Code, const tooling::Replacements &Replaces,
185 const format::FormatStyle &Style);
186
187/// A set of edits generated for a single file. Can verify whether it is safe to
188/// apply these edits to a code block.
189struct Edit {
190 tooling::Replacements Replacements;
191 std::string InitialCode;
192
193 Edit() = default;
194
195 Edit(llvm::StringRef Code, tooling::Replacements Reps)
196 : Replacements(std::move(Reps)), InitialCode(Code) {}
197
198 /// Returns the file contents after changes are applied.
199 llvm::Expected<std::string> apply() const;
200
201 /// Represents Replacements as TextEdits that are available for use in LSP.
202 std::vector<TextEdit> asTextEdits() const;
203
204 /// Checks whether the Replacements are applicable to given Code.
205 bool canApplyTo(llvm::StringRef Code) const;
206};
207/// A mapping from absolute file path (the one used for accessing the underlying
208/// VFS) to edits.
209using FileEdits = llvm::StringMap<Edit>;
210
211/// Formats the edits and code around it according to Style. Changes
212/// Replacements to formatted ones if succeeds.
213llvm::Error reformatEdit(Edit &E, const format::FormatStyle &Style);
214
215/// Apply an incremental update to a text document.
216llvm::Error applyChange(std::string &Contents,
217 const TextDocumentContentChangeEvent &Change);
218
219/// Collects identifiers with counts in the source code.
220llvm::StringMap<unsigned> collectIdentifiers(llvm::StringRef Content,
221 const format::FormatStyle &Style);
222
223/// Collects all ranges of the given identifier in the source code.
224std::vector<Range> collectIdentifierRanges(llvm::StringRef Identifier,
225 llvm::StringRef Content,
226 const LangOptions &LangOpts);
227
228/// Collects words from the source code.
229/// Unlike collectIdentifiers:
230/// - also finds text in comments:
231/// - splits text into words
232/// - drops stopwords like "get" and "for"
233llvm::StringSet<> collectWords(llvm::StringRef Content);
234
235// Something that looks like a word in the source code.
236// Could be a "real" token that's "live" in the AST, a spelled token consumed by
237// the preprocessor, or part of a spelled token (e.g. word in a comment).
238struct SpelledWord {
239 // (Spelling) location of the start of the word.
240 SourceLocation Location;
241 // The range of the word itself, excluding any quotes.
242 // This is a subrange of the file buffer.
243 llvm::StringRef Text;
244 // Whether this word is likely to refer to an identifier. True if:
245 // - the word is a spelled identifier token
246 // - Text is identifier-like (e.g. "foo_bar")
247 // - Text is surrounded by backticks (e.g. Foo in "// returns `Foo`")
248 bool LikelyIdentifier = false;
249 // Set if the word is contained in a token spelled in the file.
250 // (This should always be true, but comments aren't retained by TokenBuffer).
251 const syntax::Token *PartOfSpelledToken = nullptr;
252 // Set if the word is exactly a token spelled in the file.
253 const syntax::Token *SpelledToken = nullptr;
254 // Set if the word is a token spelled in the file, and that token survives
255 // preprocessing to emit an expanded token spelled the same way.
256 const syntax::Token *ExpandedToken = nullptr;
257
258 // Find the unique word that contains SpelledLoc or starts/ends there.
259 static std::optional<SpelledWord> touching(SourceLocation SpelledLoc,
260 const syntax::TokenBuffer &TB,
261 const LangOptions &LangOpts);
262};
263
264/// Return true if the \p TokenName is in the list of reversed keywords of the
265/// language.
266bool isKeyword(llvm::StringRef TokenName, const LangOptions &LangOpts);
267
268/// Heuristically determine namespaces visible at a point, without parsing Code.
269/// This considers using-directives and enclosing namespace-declarations that
270/// are visible (and not obfuscated) in the file itself (not headers).
271/// Code should be truncated at the point of interest.
272///
273/// The returned vector is always non-empty.
274/// - The first element is the namespace that encloses the point: a declaration
275/// near the point would be within this namespace.
276/// - The elements are the namespaces in scope at the point: an unqualified
277/// lookup would search within these namespaces.
278///
279/// Using directives are resolved against all enclosing scopes, but no other
280/// namespace directives.
281///
282/// example:
283/// using namespace a;
284/// namespace foo {
285/// using namespace b;
286///
287/// visibleNamespaces are {"foo::", "", "a::", "b::", "foo::b::"}, not "a::b::".
288std::vector<std::string> visibleNamespaces(llvm::StringRef Code,
289 const LangOptions &LangOpts);
290
291/// Represents locations that can accept a definition.
292struct EligibleRegion {
293 /// Namespace that owns all of the EligiblePoints, e.g.
294 /// namespace a{ namespace b {^ void foo();^} }
295 /// It will be “a::b” for both carrot locations.
296 std::string EnclosingNamespace;
297 /// Offsets into the code marking eligible points to insert a function
298 /// definition.
299 std::vector<Position> EligiblePoints;
300};
301
302/// Returns most eligible region to insert a definition for \p
303/// FullyQualifiedName in the \p Code.
304/// Pseudo parses \pCode under the hood to determine namespace decls and
305/// possible insertion points. Choses the region that matches the longest prefix
306/// of \p FullyQualifiedName. Returns EOF if there are no shared namespaces.
307/// \p FullyQualifiedName should not contain anonymous namespaces.
308EligibleRegion getEligiblePoints(llvm::StringRef Code,
309 llvm::StringRef FullyQualifiedName,
310 const LangOptions &LangOpts);
311
312struct DefinedMacro {
313 llvm::StringRef Name;
314 const MacroInfo *Info;
315 /// Location of the identifier that names the macro.
316 /// Unlike Info->Location, this translates preamble-patch locations to
317 /// main-file locations.
318 SourceLocation NameLoc;
319};
320/// Gets the macro referenced by \p SpelledTok. It must be a spelled token
321/// aligned to the beginning of an identifier.
322std::optional<DefinedMacro> locateMacroAt(const syntax::Token &SpelledTok,
323 Preprocessor &PP);
324
325/// Infers whether this is a header from the FileName and LangOpts (if
326/// presents).
327bool isHeaderFile(llvm::StringRef FileName,
328 std::optional<LangOptions> LangOpts = std::nullopt);
329
330/// Returns true if the given location is in a generated protobuf file.
331bool isProtoFile(SourceLocation Loc, const SourceManager &SourceMgr);
332
333/// Returns true if Name is reserved, like _Foo or __Vector_base.
334inline bool isReservedName(llvm::StringRef Name) {
335 // This doesn't catch all cases, but the most common.
336 return Name.size() >= 2 && Name[0] == '_' &&
337 (isUppercase(c: Name[1]) || Name[1] == '_');
338}
339
340/// Translates locations inside preamble patch to their main-file equivalent
341/// using presumed locations. Returns \p Loc if it isn't inside preamble patch.
342SourceLocation translatePreamblePatchLocation(SourceLocation Loc,
343 const SourceManager &SM);
344
345/// Returns the range starting at offset and spanning the whole line. Escaped
346/// newlines are not handled.
347clangd::Range rangeTillEOL(llvm::StringRef Code, unsigned HashOffset);
348} // namespace clangd
349} // namespace clang
350#endif
351

source code of clang-tools-extra/clangd/SourceCode.h