1 //===--- Transformer.cpp - Transformer library implementation ---*- 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 #include "clang/Tooling/Transformer/Transformer.h"
10 #include "clang/ASTMatchers/ASTMatchFinder.h"
11 #include "clang/ASTMatchers/ASTMatchersInternal.h"
12 #include "clang/Basic/SourceLocation.h"
13 #include "clang/Tooling/Refactoring/AtomicChange.h"
14 #include "llvm/Support/Error.h"
15 #include <map>
16 #include <utility>
17 #include <vector>
18 
19 namespace clang {
20 namespace tooling {
21 
22 using ::clang::ast_matchers::MatchFinder;
23 
24 namespace detail {
25 
26 void TransformerImpl::onMatch(
27     const ast_matchers::MatchFinder::MatchResult &Result) {
28   if (Result.Context->getDiagnostics().hasErrorOccurred())
29     return;
30 
31   onMatchImpl(Result);
32 }
33 
34 llvm::Expected<llvm::SmallVector<AtomicChange, 1>>
35 TransformerImpl::convertToAtomicChanges(
36     const llvm::SmallVectorImpl<transformer::Edit> &Edits,
37     const MatchFinder::MatchResult &Result) {
38   // Group the transformations, by file, into AtomicChanges, each anchored by
39   // the location of the first change in that file.
40   std::map<FileID, AtomicChange> ChangesByFileID;
41   for (const auto &T : Edits) {
42     auto ID = Result.SourceManager->getFileID(T.Range.getBegin());
43     auto Iter = ChangesByFileID
44                     .emplace(ID, AtomicChange(*Result.SourceManager,
45                                               T.Range.getBegin(), T.Metadata))
46                     .first;
47     auto &AC = Iter->second;
48     switch (T.Kind) {
49     case transformer::EditKind::Range:
50       if (auto Err =
51               AC.replace(*Result.SourceManager, T.Range, T.Replacement)) {
52         return std::move(Err);
53       }
54       break;
55     case transformer::EditKind::AddInclude:
56       AC.addHeader(T.Replacement);
57       break;
58     }
59   }
60 
61   llvm::SmallVector<AtomicChange, 1> Changes;
62   Changes.reserve(ChangesByFileID.size());
63   for (auto &IDChangePair : ChangesByFileID)
64     Changes.push_back(std::move(IDChangePair.second));
65 
66   return Changes;
67 }
68 
69 void NoMetadataImpl::onMatchImpl(const MatchFinder::MatchResult &Result) {
70   size_t I = transformer::detail::findSelectedCase(Result, Rule);
71   auto Transformations = Rule.Cases[I].Edits(Result);
72   if (!Transformations) {
73     Consumer(Transformations.takeError());
74     return;
75   }
76 
77   if (Transformations->empty())
78     return;
79 
80   auto Changes = convertToAtomicChanges(*Transformations, Result);
81   if (!Changes) {
82     Consumer(Changes.takeError());
83     return;
84   }
85 
86   Consumer(llvm::MutableArrayRef<AtomicChange>(*Changes));
87 }
88 
89 } // namespace detail
90 
91 void Transformer::registerMatchers(MatchFinder *MatchFinder) {
92   for (auto &Matcher : Impl->buildMatchers())
93     MatchFinder->addDynamicMatcher(Matcher, this);
94 }
95 
96 void Transformer::run(const MatchFinder::MatchResult &Result) {
97   if (Result.Context->getDiagnostics().hasErrorOccurred())
98     return;
99 
100   Impl->onMatch(Result);
101 }
102 
103 } // namespace tooling
104 } // namespace clang
105