347f347580
Look for nested if statements with relatively small conditions, where they can be collapsed into one if statement. Change-Id: I7d5d4e418d0ce928991a3308fc88969c00c0d0f2 Reviewed-on: https://gerrit.libreoffice.org/62898 Tested-by: Jenkins Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
129 lines
4 KiB
C++
129 lines
4 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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#include <cassert>
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#include <string>
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#include <iostream>
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#include <unordered_map>
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#include <unordered_set>
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#include "plugin.hxx"
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#include "check.hxx"
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#include "clang/AST/CXXInheritance.h"
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#include "clang/AST/StmtVisitor.h"
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/**
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Look for nested if statements with relatively small conditions, where they can be collapsed into
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one if statement.
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*/
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namespace
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{
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class CollapseIf : public loplugin::FilteringPlugin<CollapseIf>
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{
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public:
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explicit CollapseIf(loplugin::InstantiationData const& data)
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: FilteringPlugin(data)
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{
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}
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virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
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bool VisitIfStmt(IfStmt const*);
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private:
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int getNoCharsInSourceCodeOfExpr(IfStmt const*);
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bool containsComment(Stmt const* stmt);
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};
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bool CollapseIf::VisitIfStmt(IfStmt const* ifStmt)
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{
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if (ignoreLocation(ifStmt))
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return true;
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if (ifStmt->getElse())
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return true;
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IfStmt const* secondIfStmt = nullptr;
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if (auto compoundStmt = dyn_cast<CompoundStmt>(ifStmt->getThen()))
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{
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if (compoundStmt->size() != 1)
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return true;
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secondIfStmt = dyn_cast<IfStmt>(*compoundStmt->body_begin());
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if (!secondIfStmt)
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return true;
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if (secondIfStmt->getElse())
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return true;
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}
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else
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{
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secondIfStmt = dyn_cast<IfStmt>(ifStmt->getThen());
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if (!secondIfStmt)
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return true;
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}
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int noChars1 = getNoCharsInSourceCodeOfExpr(ifStmt);
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int noChars2 = getNoCharsInSourceCodeOfExpr(secondIfStmt);
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if (noChars1 + noChars2 > 40)
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return true;
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// Sometimes there is a comment between the first and second if, so
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// merging them would make the comment more awkward to write.
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if (containsComment(ifStmt))
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return true;
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report(DiagnosticsEngine::Warning, "nested if should be collapsed into one statement %0 %1",
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compat::getBeginLoc(ifStmt))
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<< noChars1 << noChars2 << ifStmt->getSourceRange();
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return true;
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}
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int CollapseIf::getNoCharsInSourceCodeOfExpr(IfStmt const* ifStmt)
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{
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// Measure the space between the "if" the beginning of the "then" block because
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// measuring the size of the condition expression is unreliable, because clang
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// does not report the location of the last token accurately.
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SourceManager& SM = compiler.getSourceManager();
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SourceLocation startLoc = compat::getBeginLoc(ifStmt);
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SourceLocation endLoc = compat::getBeginLoc(ifStmt->getThen());
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char const* p1 = SM.getCharacterData(startLoc);
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char const* p2 = SM.getCharacterData(endLoc);
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int count = 0;
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for (auto p = p1; p < p2; ++p)
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if (*p != ' ')
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++count;
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return count;
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}
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bool CollapseIf::containsComment(Stmt const* stmt)
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{
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SourceManager& SM = compiler.getSourceManager();
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auto range = stmt->getSourceRange();
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SourceLocation startLoc = range.getBegin();
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SourceLocation endLoc = range.getEnd();
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char const* p1 = SM.getCharacterData(startLoc);
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char const* p2 = SM.getCharacterData(endLoc);
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p2 += Lexer::MeasureTokenLength(endLoc, SM, compiler.getLangOpts());
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// check for comments
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constexpr char const comment1[] = "/*";
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constexpr char const comment2[] = "//";
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if (std::search(p1, p2, comment1, comment1 + strlen(comment1)) != p2)
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return true;
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if (std::search(p1, p2, comment2, comment2 + strlen(comment2)) != p2)
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return true;
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return false;
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}
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/** Off by default because some places are a judgement call if it should be collapsed or not. */
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loplugin::Plugin::Registration<CollapseIf> X("collapseif", false);
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}
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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