1//===--- SwapIfBranches.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 "ParsedAST.h"
9#include "SourceCode.h"
10#include "refactor/Tweak.h"
11#include "support/Logger.h"
12#include "clang/AST/ASTContext.h"
13#include "clang/AST/Stmt.h"
14#include "clang/Basic/LangOptions.h"
15#include "clang/Basic/SourceLocation.h"
16#include "clang/Basic/SourceManager.h"
17#include "clang/Tooling/Core/Replacement.h"
18#include "llvm/ADT/StringRef.h"
19#include "llvm/Support/Casting.h"
20#include "llvm/Support/Error.h"
21
22namespace clang {
23namespace clangd {
24namespace {
25/// Swaps the 'then' and 'else' branch of the if statement.
26/// Before:
27/// if (foo) { return 10; } else { continue; }
28/// ^^^^^^^ ^^^^
29/// After:
30/// if (foo) { continue; } else { return 10; }
31class SwapIfBranches : public Tweak {
32public:
33 const char *id() const final;
34
35 bool prepare(const Selection &Inputs) override;
36 Expected<Effect> apply(const Selection &Inputs) override;
37 std::string title() const override { return "Swap if branches"; }
38 llvm::StringLiteral kind() const override {
39 return CodeAction::REFACTOR_KIND;
40 }
41 bool hidden() const override { return true; }
42
43private:
44 const IfStmt *If = nullptr;
45};
46
47REGISTER_TWEAK(SwapIfBranches)
48
49bool SwapIfBranches::prepare(const Selection &Inputs) {
50 for (const SelectionTree::Node *N = Inputs.ASTSelection.commonAncestor();
51 N && !If; N = N->Parent) {
52 // Stop once we hit a block, e.g. a lambda in the if condition.
53 if (llvm::isa_and_nonnull<CompoundStmt>(N->ASTNode.get<Stmt>()))
54 return false;
55 If = dyn_cast_or_null<IfStmt>(N->ASTNode.get<Stmt>());
56 }
57 // avoid dealing with single-statement brances, they require careful handling
58 // to avoid changing semantics of the code (i.e. dangling else).
59 return If && isa_and_nonnull<CompoundStmt>(Val: If->getThen()) &&
60 isa_and_nonnull<CompoundStmt>(Val: If->getElse());
61}
62
63Expected<Tweak::Effect> SwapIfBranches::apply(const Selection &Inputs) {
64 auto &Ctx = Inputs.AST->getASTContext();
65 auto &SrcMgr = Inputs.AST->getSourceManager();
66
67 auto ThenRng = toHalfOpenFileRange(Mgr: SrcMgr, LangOpts: Ctx.getLangOpts(),
68 R: If->getThen()->getSourceRange());
69 if (!ThenRng)
70 return error(Fmt: "Could not obtain range of the 'then' branch. Macros?");
71 auto ElseRng = toHalfOpenFileRange(Mgr: SrcMgr, LangOpts: Ctx.getLangOpts(),
72 R: If->getElse()->getSourceRange());
73 if (!ElseRng)
74 return error(Fmt: "Could not obtain range of the 'else' branch. Macros?");
75
76 auto ThenCode = toSourceCode(SM: SrcMgr, R: *ThenRng);
77 auto ElseCode = toSourceCode(SM: SrcMgr, R: *ElseRng);
78
79 tooling::Replacements Result;
80 if (auto Err = Result.add(R: tooling::Replacement(Ctx.getSourceManager(),
81 ThenRng->getBegin(),
82 ThenCode.size(), ElseCode)))
83 return std::move(Err);
84 if (auto Err = Result.add(R: tooling::Replacement(Ctx.getSourceManager(),
85 ElseRng->getBegin(),
86 ElseCode.size(), ThenCode)))
87 return std::move(Err);
88 return Effect::mainFileEdit(SM: SrcMgr, Replacements: std::move(Result));
89}
90
91} // namespace
92} // namespace clangd
93} // namespace clang
94

source code of clang-tools-extra/clangd/refactor/tweaks/SwapIfBranches.cpp