94 lines · cpp
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-exception6//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 handling58 // to avoid changing semantics of the code (i.e. dangling else).59 return If && isa_and_nonnull<CompoundStmt>(If->getThen()) &&60 isa_and_nonnull<CompoundStmt>(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(SrcMgr, Ctx.getLangOpts(),68 If->getThen()->getSourceRange());69 if (!ThenRng)70 return error("Could not obtain range of the 'then' branch. Macros?");71 auto ElseRng = toHalfOpenFileRange(SrcMgr, Ctx.getLangOpts(),72 If->getElse()->getSourceRange());73 if (!ElseRng)74 return error("Could not obtain range of the 'else' branch. Macros?");75 76 auto ThenCode = toSourceCode(SrcMgr, *ThenRng);77 auto ElseCode = toSourceCode(SrcMgr, *ElseRng);78 79 tooling::Replacements Result;80 if (auto Err = Result.add(tooling::Replacement(Ctx.getSourceManager(),81 ThenRng->getBegin(),82 ThenCode.size(), ElseCode)))83 return std::move(Err);84 if (auto Err = Result.add(tooling::Replacement(Ctx.getSourceManager(),85 ElseRng->getBegin(),86 ElseCode.size(), ThenCode)))87 return std::move(Err);88 return Effect::mainFileEdit(SrcMgr, std::move(Result));89}90 91} // namespace92} // namespace clangd93} // namespace clang94