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| //===--- SwapIfBranches.cpp --------------------------------------*- C++-*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "Logger.h"
#include "ParsedAST.h"
#include "SourceCode.h"
#include "refactor/Tweak.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/Stmt.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Lex/Lexer.h"
#include "clang/Tooling/Core/Replacement.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Error.h"
namespace clang {
namespace clangd {
namespace {
/// Swaps the 'then' and 'else' branch of the if statement.
/// Before:
/// if (foo) { return 10; } else { continue; }
/// ^^^^^^^ ^^^^
/// After:
/// if (foo) { continue; } else { return 10; }
class SwapIfBranches : public Tweak {
public:
const char *id() const override final;
bool prepare(const Selection &Inputs) override;
Expected<Effect> apply(const Selection &Inputs) override;
std::string title() const override { return "Swap if branches"; }
Intent intent() const override { return Refactor; }
private:
const IfStmt *If = nullptr;
};
REGISTER_TWEAK(SwapIfBranches)
bool SwapIfBranches::prepare(const Selection &Inputs) {
for (const SelectionTree::Node *N = Inputs.ASTSelection.commonAncestor();
N && !If; N = N->Parent) {
// Stop once we hit a block, e.g. a lambda in the if condition.
if (dyn_cast_or_null<CompoundStmt>(N->ASTNode.get<Stmt>()))
return false;
If = dyn_cast_or_null<IfStmt>(N->ASTNode.get<Stmt>());
}
// avoid dealing with single-statement brances, they require careful handling
// to avoid changing semantics of the code (i.e. dangling else).
return If && dyn_cast_or_null<CompoundStmt>(If->getThen()) &&
dyn_cast_or_null<CompoundStmt>(If->getElse());
}
Expected<Tweak::Effect> SwapIfBranches::apply(const Selection &Inputs) {
auto &Ctx = Inputs.AST.getASTContext();
auto &SrcMgr = Inputs.AST.getSourceManager();
auto ThenRng = toHalfOpenFileRange(SrcMgr, Ctx.getLangOpts(),
If->getThen()->getSourceRange());
if (!ThenRng)
return llvm::createStringError(
llvm::inconvertibleErrorCode(),
"Could not obtain range of the 'then' branch. Macros?");
auto ElseRng = toHalfOpenFileRange(SrcMgr, Ctx.getLangOpts(),
If->getElse()->getSourceRange());
if (!ElseRng)
return llvm::createStringError(
llvm::inconvertibleErrorCode(),
"Could not obtain range of the 'else' branch. Macros?");
auto ThenCode = toSourceCode(SrcMgr, *ThenRng);
auto ElseCode = toSourceCode(SrcMgr, *ElseRng);
tooling::Replacements Result;
if (auto Err = Result.add(tooling::Replacement(Ctx.getSourceManager(),
ThenRng->getBegin(),
ThenCode.size(), ElseCode)))
return std::move(Err);
if (auto Err = Result.add(tooling::Replacement(Ctx.getSourceManager(),
ElseRng->getBegin(),
ElseCode.size(), ThenCode)))
return std::move(Err);
return Effect::mainFileEdit(SrcMgr, std::move(Result));
}
} // namespace
} // namespace clangd
} // namespace clang
|