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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#include <cassert>
#include <string>
#include <iostream>
#include <unordered_map>
#include <unordered_set>
#include "plugin.hxx"
#include "check.hxx"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/StmtVisitor.h"
/**
Look for nested if statements with relatively small conditions, where they can be collapsed into
one if statement.
*/
namespace
{
class CollapseIf : public loplugin::FilteringPlugin<CollapseIf>
{
public:
explicit CollapseIf(loplugin::InstantiationData const& data)
: FilteringPlugin(data)
{
}
virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
bool VisitIfStmt(IfStmt const*);
private:
int getNoCharsInSourceCodeOfExpr(IfStmt const*);
bool containsComment(Stmt const* stmt);
};
bool CollapseIf::VisitIfStmt(IfStmt const* ifStmt)
{
if (ignoreLocation(ifStmt))
return true;
if (ifStmt->getElse())
return true;
IfStmt const* secondIfStmt = nullptr;
if (auto compoundStmt = dyn_cast<CompoundStmt>(ifStmt->getThen()))
{
if (compoundStmt->size() != 1)
return true;
secondIfStmt = dyn_cast<IfStmt>(*compoundStmt->body_begin());
if (!secondIfStmt)
return true;
if (secondIfStmt->getElse())
return true;
}
else
{
secondIfStmt = dyn_cast<IfStmt>(ifStmt->getThen());
if (!secondIfStmt)
return true;
}
int noChars1 = getNoCharsInSourceCodeOfExpr(ifStmt);
int noChars2 = getNoCharsInSourceCodeOfExpr(secondIfStmt);
if (noChars1 + noChars2 > 40)
return true;
// Sometimes there is a comment between the first and second if, so
// merging them would make the comment more awkward to write.
if (containsComment(ifStmt))
return true;
report(DiagnosticsEngine::Warning, "nested if should be collapsed into one statement %0 %1",
compat::getBeginLoc(ifStmt))
<< noChars1 << noChars2 << ifStmt->getSourceRange();
return true;
}
int CollapseIf::getNoCharsInSourceCodeOfExpr(IfStmt const* ifStmt)
{
// Measure the space between the "if" the beginning of the "then" block because
// measuring the size of the condition expression is unreliable, because clang
// does not report the location of the last token accurately.
SourceManager& SM = compiler.getSourceManager();
SourceLocation startLoc = compat::getBeginLoc(ifStmt);
SourceLocation endLoc = compat::getBeginLoc(ifStmt->getThen());
char const* p1 = SM.getCharacterData(startLoc);
char const* p2 = SM.getCharacterData(endLoc);
int count = 0;
for (auto p = p1; p < p2; ++p)
if (*p != ' ')
++count;
return count;
}
bool CollapseIf::containsComment(Stmt const* stmt)
{
SourceManager& SM = compiler.getSourceManager();
auto range = stmt->getSourceRange();
SourceLocation startLoc = range.getBegin();
SourceLocation endLoc = range.getEnd();
char const* p1 = SM.getCharacterData(startLoc);
char const* p2 = SM.getCharacterData(endLoc);
p2 += Lexer::MeasureTokenLength(endLoc, SM, compiler.getLangOpts());
// check for comments
constexpr char const comment1[] = "/*";
constexpr char const comment2[] = "//";
if (std::search(p1, p2, comment1, comment1 + strlen(comment1)) != p2)
return true;
if (std::search(p1, p2, comment2, comment2 + strlen(comment2)) != p2)
return true;
return false;
}
/** Off by default because some places are a judgement call if it should be collapsed or not. */
loplugin::Plugin::Registration<CollapseIf> X("collapseif", false);
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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