/* -*- 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/.
 */
#ifndef LO_CLANG_SHARED_PLUGINS

#include "plugin.hxx"
#include "check.hxx"
#include "compat.hxx"
#include <iostream>

/**
  Check for
   (*) calls to CPPUNIT_ASSERT when it should be using CPPUNIT_ASSERT_EQUALS
   (*) calls to CPPUNIT_ASSERT_EQUALS where the constant is the second param
*/

namespace {

class CppunitAssertEquals:
    public loplugin::FilteringPlugin<CppunitAssertEquals>
{
public:
    explicit CppunitAssertEquals(loplugin::InstantiationData const & data):
        FilteringPlugin(data) {}

    virtual bool preRun() override
    {
        return compiler.getLangOpts().CPlusPlus;
    }

    virtual void run() override
    {
        if (preRun()) {
            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
        }
    }

    bool VisitCallExpr(const CallExpr*);

private:
    void checkExpr(
        SourceRange range, StringRef name, Expr const * expr, bool negated);

    void reportEquals(SourceRange range, StringRef name, bool negative);

    bool isCompileTimeConstant(Expr const * expr);
};

bool CppunitAssertEquals::VisitCallExpr(const CallExpr* callExpr)
{
    auto const decl = callExpr->getDirectCallee();
    if (!decl)
        return true;
    /*
       calls to CPPUNIT_ASSERT when it should be using CPPUNIT_ASSERT_EQUALS
    */
    if (loplugin::DeclCheck(decl).Function("failIf").Struct("Asserter")
             .Namespace("CppUnit").GlobalNamespace())
    {
        // Don't use callExpr->getLocStart() or callExpr->getExprLoc(), as those
        // fall into a nested use of the CPPUNIT_NS macro; CallExpr::getRParenLoc
        // happens to be readily available and cause good results:
        auto loc = callExpr->getRParenLoc();
        while (compiler.getSourceManager().isMacroArgExpansion(loc)) {
            loc = compiler.getSourceManager().getImmediateMacroCallerLoc(loc);
        }
        if (!compiler.getSourceManager().isMacroBodyExpansion(loc)
            || ignoreLocation(
                compiler.getSourceManager().getImmediateMacroCallerLoc(loc)))
        {
            return true;
        }
        auto name = Lexer::getImmediateMacroName(
            loc, compiler.getSourceManager(), compiler.getLangOpts());
        if (name != "CPPUNIT_ASSERT" && name != "CPPUNIT_ASSERT_MESSAGE") {
            return true;
        }
        if (decl->getNumParams() != 3) {
            report(
                DiagnosticsEngine::Warning,
                ("TODO: suspicious CppUnit::Asserter::failIf call with %0"
                 " parameters"),
                callExpr->getExprLoc())
                << decl->getNumParams() << callExpr->getSourceRange();
            return true;
        }
        auto const e1 = callExpr->getArg(0)->IgnoreParenImpCasts();
        Expr const * e2 = nullptr;
        if (auto const e3 = dyn_cast<UnaryOperator>(e1)) {
            if (e3->getOpcode() == UO_LNot) {
                e2 = e3->getSubExpr();
            }
        } else if (auto const e4 = dyn_cast<CXXOperatorCallExpr>(e1)) {
            if (e4->getOperator() == OO_Exclaim) {
                e2 = e4->getArg(0);
            }
        }
        if (e2 == nullptr) {
            report(
                DiagnosticsEngine::Warning,
                ("TODO: suspicious CppUnit::Asserter::failIf call not wrapping"
                 " !(...)"),
                callExpr->getExprLoc())
                << callExpr->getSourceRange();
            return true;
        }
        auto range = compat::getImmediateExpansionRange(compiler.getSourceManager(), loc);
        checkExpr(
            SourceRange(range.first, range.second), name,
            e2->IgnoreParenImpCasts(), false);
    }

    /**
      Check for calls to CPPUNIT_ASSERT_EQUALS where the constant is the second param
    */
    if (loplugin::DeclCheck(decl).Function("assertEquals").
             Namespace("CppUnit").GlobalNamespace())
    {
        // can happen in template test code that both params are compile time constants
        if (isCompileTimeConstant(callExpr->getArg(0)))
            return true;
        if (isCompileTimeConstant(callExpr->getArg(1)))
            report(
                DiagnosticsEngine::Warning,
                "CPPUNIT_ASSERT_EQUALS parameters look switched, expected value should be first param",
                callExpr->getExprLoc())
                << callExpr->getSourceRange();
    }
    return true;
}

// copied from stringconcat.cxx
Expr const * stripConstructor(Expr const * expr) {
    auto e0 = expr;
    auto const e1 = dyn_cast<CXXFunctionalCastExpr>(e0);
    if (e1 != nullptr) {
        e0 = e1->getSubExpr()->IgnoreParenImpCasts();
    }
    auto const e2 = dyn_cast<CXXBindTemporaryExpr>(e0);
    if (e2 == nullptr) {
        return expr;
    }
    auto const e3 = dyn_cast<CXXConstructExpr>(
        e2->getSubExpr()->IgnoreParenImpCasts());
    if (e3 == nullptr) {
        return expr;
    }
    auto qt = loplugin::DeclCheck(e3->getConstructor());
    if (!((qt.MemberFunction().Class("OString").Namespace("rtl")
           .GlobalNamespace())
          || (qt.MemberFunction().Class("OUString").Namespace("rtl")
              .GlobalNamespace())))
    {
        return expr;
    }
    if (e3->getNumArgs() != 2) {
        return expr;
    }
    return e3->getArg(0)->IgnoreParenImpCasts();
}

bool CppunitAssertEquals::isCompileTimeConstant(Expr const * expr)
{
    if (expr->isIntegerConstantExpr(compiler.getASTContext()))
        return true;
    // is string literal ?
    expr = expr->IgnoreParenImpCasts();
    expr = stripConstructor(expr);
    return isa<clang::StringLiteral>(expr);
}

void CppunitAssertEquals::checkExpr(
    SourceRange range, StringRef name, Expr const * expr, bool negated)
{
    if (auto const e = dyn_cast<UnaryOperator>(expr)) {
        if (e->getOpcode() == UO_LNot) {
            checkExpr(
                range, name, e->getSubExpr()->IgnoreParenImpCasts(), !negated);
        }
        return;
    }
    if (auto const e = dyn_cast<BinaryOperator>(expr)) {
        auto const op = e->getOpcode();
        if ((!negated && op == BO_EQ) || (negated && op == BO_NE)) {
            reportEquals(range, name, op == BO_NE);
            return;
        }
#if 0 // TODO: enable later
        if ((!negated && op == BO_LAnd) || (negated && op == BO_LOr)) {
            report(
                DiagnosticsEngine::Warning,
                "rather split into two %0", e->getExprLoc())
                << name << range;
            return;
        }
#endif
        return;
    }
    if (auto const e = dyn_cast<CXXOperatorCallExpr>(expr)) {
        auto const op = e->getOperator();
        if ((!negated && op == OO_EqualEqual)
            || (negated && op == OO_ExclaimEqual))
        {
            reportEquals(range, name, op == OO_ExclaimEqual);
            return;
        }
        return;
    }
}

void CppunitAssertEquals::reportEquals(
    SourceRange range, StringRef name, bool negative)
{
    report(
        DiagnosticsEngine::Warning,
        ("rather call"
         " %select{CPPUNIT_ASSERT_EQUAL|CPPUNIT_ASSERT_EQUAL_MESSAGE}0 (or"
         " rewrite as an explicit operator %select{==|!=}1 call when the"
         " operator itself is the topic)"),
        range.getBegin())
        << (name == "CPPUNIT_ASSERT_MESSAGE") << negative << range;
}

loplugin::Plugin::Registration< CppunitAssertEquals > cppunitassertequals("cppunitassertequals");

} // namespace

#endif // LO_CLANG_SHARED_PLUGINS

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