1 //===--- SemanticSelection.cpp -----------------------------------*- 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 #include "SemanticSelection.h"
9 #include "FindSymbols.h"
10 #include "ParsedAST.h"
11 #include "Protocol.h"
12 #include "Selection.h"
13 #include "SourceCode.h"
14 #include "clang/AST/DeclBase.h"
15 #include "clang/Basic/SourceLocation.h"
16 #include "llvm/ADT/ArrayRef.h"
17 #include "llvm/Support/Error.h"
18
19 namespace clang {
20 namespace clangd {
21 namespace {
22
23 // Adds Range \p R to the Result if it is distinct from the last added Range.
24 // Assumes that only consecutive ranges can coincide.
addIfDistinct(const Range & R,std::vector<Range> & Result)25 void addIfDistinct(const Range &R, std::vector<Range> &Result) {
26 if (Result.empty() || Result.back() != R) {
27 Result.push_back(R);
28 }
29 }
30
31 // Recursively collects FoldingRange from a symbol and its children.
collectFoldingRanges(DocumentSymbol Symbol,std::vector<FoldingRange> & Result)32 void collectFoldingRanges(DocumentSymbol Symbol,
33 std::vector<FoldingRange> &Result) {
34 FoldingRange Range;
35 Range.startLine = Symbol.range.start.line;
36 Range.startCharacter = Symbol.range.start.character;
37 Range.endLine = Symbol.range.end.line;
38 Range.endCharacter = Symbol.range.end.character;
39 Result.push_back(Range);
40 for (const auto &Child : Symbol.children)
41 collectFoldingRanges(Child, Result);
42 }
43
44 } // namespace
45
getSemanticRanges(ParsedAST & AST,Position Pos)46 llvm::Expected<SelectionRange> getSemanticRanges(ParsedAST &AST, Position Pos) {
47 std::vector<Range> Ranges;
48 const auto &SM = AST.getSourceManager();
49 const auto &LangOpts = AST.getLangOpts();
50
51 auto FID = SM.getMainFileID();
52 auto Offset = positionToOffset(SM.getBufferData(FID), Pos);
53 if (!Offset) {
54 return Offset.takeError();
55 }
56
57 // Get node under the cursor.
58 SelectionTree ST = SelectionTree::createRight(
59 AST.getASTContext(), AST.getTokens(), *Offset, *Offset);
60 for (const auto *Node = ST.commonAncestor(); Node != nullptr;
61 Node = Node->Parent) {
62 if (const Decl *D = Node->ASTNode.get<Decl>()) {
63 if (llvm::isa<TranslationUnitDecl>(D)) {
64 break;
65 }
66 }
67
68 auto SR = toHalfOpenFileRange(SM, LangOpts, Node->ASTNode.getSourceRange());
69 if (!SR.hasValue() || SM.getFileID(SR->getBegin()) != SM.getMainFileID()) {
70 continue;
71 }
72 Range R;
73 R.start = sourceLocToPosition(SM, SR->getBegin());
74 R.end = sourceLocToPosition(SM, SR->getEnd());
75 addIfDistinct(R, Ranges);
76 }
77
78 if (Ranges.empty()) {
79 // LSP provides no way to signal "the point is not within a semantic range".
80 // Return an empty range at the point.
81 SelectionRange Empty;
82 Empty.range.start = Empty.range.end = Pos;
83 return std::move(Empty);
84 }
85
86 // Convert to the LSP linked-list representation.
87 SelectionRange Head;
88 Head.range = std::move(Ranges.front());
89 SelectionRange *Tail = &Head;
90 for (auto &Range :
91 llvm::makeMutableArrayRef(Ranges.data(), Ranges.size()).drop_front()) {
92 Tail->parent = std::make_unique<SelectionRange>();
93 Tail = Tail->parent.get();
94 Tail->range = std::move(Range);
95 }
96
97 return std::move(Head);
98 }
99
100 // FIXME(kirillbobyrev): Collect comments, PP conditional regions, includes and
101 // other code regions (e.g. public/private/protected sections of classes,
102 // control flow statement bodies).
103 // Related issue:
104 // https://github.com/clangd/clangd/issues/310
getFoldingRanges(ParsedAST & AST)105 llvm::Expected<std::vector<FoldingRange>> getFoldingRanges(ParsedAST &AST) {
106 // FIXME(kirillbobyrev): getDocumentSymbols() is conveniently available but
107 // limited (e.g. doesn't yield blocks inside functions and provides ranges for
108 // nodes themselves instead of their contents which is less useful). Replace
109 // this with a more general RecursiveASTVisitor implementation instead.
110 auto DocumentSymbols = getDocumentSymbols(AST);
111 if (!DocumentSymbols)
112 return DocumentSymbols.takeError();
113 std::vector<FoldingRange> Result;
114 for (const auto &Symbol : *DocumentSymbols)
115 collectFoldingRanges(Symbol, Result);
116 return Result;
117 }
118
119 } // namespace clangd
120 } // namespace clang
121