checkclass.cpp

cppcheck is a static C/C++ code analyzer that checks for memory leaks, mismatching allocation-deallo

/*
 * Cppcheck - A tool for static C/C++ code analysis
 * Copyright (C) 2007-2009 Daniel Marjamäki, Reijo Tomperi, Nicolas Le Cam,
 * Leandro Penz, Kimmo Varis, Vesa Pikki
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/
 */

//---------------------------------------------------------------------------
#include "checkclass.h"

#include <locale>

#include <cstring>
#include <string>
#include <sstream>
#include <algorithm>

//---------------------------------------------------------------------------

CheckClass::CheckClass(const Tokenizer *tokenizer, const Settings &settings, ErrorLogger *errorLogger)
{
    _tokenizer = tokenizer;
    _settings = settings;
    _errorLogger = errorLogger;
}

CheckClass::~CheckClass()
{

}

//---------------------------------------------------------------------------

struct CheckClass::VAR *CheckClass::ClassChecking_GetVarList(const Token *tok1)
{
    // Get variable list..
    struct VAR *varlist = NULL;
    unsigned int indentlevel = 0;
    for (const Token *tok = tok1; tok; tok = tok->next())
    {
        if (!tok->next())
            break;

        if (tok->str() == "{")
            ++indentlevel;
        else if (tok->str() == "}")
        {
            if (indentlevel <= 1)
                break;
            --indentlevel;
        }

        if (indentlevel != 1)
            continue;

        // "private:" "public:" "protected:" etc
        bool b = bool((*tok->strAt(0) != ':') && strchr(tok->strAt(0), ':') != 0);

        // Search for start of statement..
        if (! Token::Match(tok, "[;{}]") && ! b)
            continue;

        // This is the start of a statement
        const Token *next = tok->next();
        const char *varname = 0;

        // If next token contains a ":".. it is not part of a variable declaration
        if (next->str().find(":") != std::string::npos)
        {

        }

        // Is it a variable declaration?
        else if (Token::Match(next, "%type% %var% ;"))
        {
            if (next->isStandardType())
                varname = next->strAt(1);
            else if (Token::findmatch(_tokenizer->tokens(), ("enum " + next->str()).c_str()))
                varname = next->strAt(1);
        }

        // Pointer?
        else if (Token::Match(next, "%type% * %var% ;"))
        {
            varname = next->strAt(2);
        }

        // If the varname was set in one of the two if-block above, create a entry for this variable..
        if (varname)
        {
            struct VAR *var = new VAR(varname, false, varlist);
            varlist   = var;
        }
    }

    return varlist;
}
//---------------------------------------------------------------------------

const Token * CheckClass::FindClassFunction(const Token *tok, const char classname[], const char funcname[], int &indentlevel)
{
    if (indentlevel < 0 || tok == NULL)
        return NULL;

    std::ostringstream classPattern;
    classPattern << "class " << classname << " :|{";

    std::ostringstream internalPattern;
    internalPattern << funcname << " (";

    std::ostringstream externalPattern;
    externalPattern << classname << " :: " << funcname << " (";

    for (;tok; tok = tok->next())
    {
        if (indentlevel == 0 && Token::Match(tok, classPattern.str().c_str()))
        {
            while (tok && tok->str() != "{")
                tok = tok->next();
            if (tok)
                tok = tok->next();
            if (! tok)
                break;
            indentlevel = 1;
        }

        if (tok->str() == "{")
        {
            // If indentlevel==0 don't go to indentlevel 1. Skip the block.
            if (indentlevel > 0)
                ++indentlevel;

            else
            {
                for (; tok; tok = tok->next())
                {
                    if (tok->str() == "{")
                        ++indentlevel;
                    else if (tok->str() == "}")
                    {
                        --indentlevel;
                        if (indentlevel <= 0)
                            break;
                    }
                }
                if (tok == NULL)
                    return NULL;

                continue;
            }
        }

        if (tok->str() == "}")
        {
            --indentlevel;
            if (indentlevel < 0)
                return NULL;
        }

        if (indentlevel == 1)
        {
            // Member function implemented in the class declaration?
            if (tok->str() != "~" && Token::Match(tok->next(), internalPattern.str().c_str()))
            {
                const Token *tok2 = tok->next();
                while (tok2 && tok2->str() != "{" && tok2->str() != ";")
                    tok2 = tok2->next();
                if (tok2 && tok2->str() == "{")
                    return tok->next();
            }
        }

        else if (indentlevel == 0 && Token::Match(tok, externalPattern.str().c_str()))
        {
            return tok;
        }
    }

    // Not found
    return NULL;
}
//---------------------------------------------------------------------------

void CheckClass::InitVar(struct VAR *varlist, const char varname[])
{
    for (struct VAR *var = varlist; var; var = var->next)
    {
        if (strcmp(var->name, varname) == 0)
        {
            var->init = true;
            break;
        }
    }
}
//---------------------------------------------------------------------------

void CheckClass::ClassChecking_VarList_Initialize(const Token *tok1, const Token *ftok, struct VAR *varlist, const char classname[], std::list<std::string> &callstack)
{
    bool Assign = false;
    unsigned int indentlevel = 0;

    for (; ftok; ftok = ftok->next())
    {
        if (!ftok->next())
            break;

        // Class constructor.. initializing variables like this
        // clKalle::clKalle() : var(value) { }
        if (indentlevel == 0)
        {
            if (Assign && Token::Match(ftok, "%var% ("))
            {
                InitVar(varlist, ftok->aaaa());
            }

            Assign |= (ftok->str() == ":");
        }


        if (ftok->str() == "{")
        {
            ++indentlevel;
            Assign = false;
        }

        if (ftok->str() == "}")
        {
            if (indentlevel <= 1)
                break;
            --indentlevel;
        }

        if (indentlevel < 1)
            continue;

        // Variable getting value from stream?
        if (Token::Match(ftok, ">> %var%"))
        {
            InitVar(varlist, ftok->next()->aaaa());
        }

        // Before a new statement there is "[{};)=]" or "else"
        if (! Token::Match(ftok, "[{};)=]") && ftok->str() != "else")
            continue;

        // Using the operator= function to initialize all variables..
        if (Token::simpleMatch(ftok->next(), "* this = "))
        {
            for (struct VAR *var = varlist; var; var = var->next)
                var->init = true;
            break;
        }

        if (!Token::Match(ftok->next(), "%var%") && !Token::Match(ftok->next(), "this . %var%"))
            continue;

        // Goto the first token in this statement..
        ftok = ftok->next();

        // Skip "this->"
        if (Token::simpleMatch(ftok, "this ."))
            ftok = ftok->tokAt(2);

        // Clearing all variables..
        if (Token::simpleMatch(ftok, "memset ( this ,"))
        {
            for (struct VAR *var = varlist; var; var = var->next)
                var->init = true;
            break;
        }

        // Calling member function?
        else if (Token::Match(ftok, "%var% ("))
        {
            // No recursive calls!
            if (std::find(callstack.begin(), callstack.end(), ftok->str()) == callstack.end())
            {
                callstack.push_back(ftok->str());
                int i = 0;
                const Token *ftok2 = FindClassFunction(tok1, classname, ftok->aaaa(), i);
                ClassChecking_VarList_Initialize(tok1, ftok2, varlist, classname, callstack);
            }
        }

        // Assignment of member variable?
        else if (Token::Match(ftok, "%var% ="))
        {
            InitVar(varlist, ftok->aaaa());
        }

        // The functions 'clear' and 'Clear' are supposed to initialize variable.
        if (Token::Match(ftok, "%var% . clear|Clear ("))
        {
            InitVar(varlist, ftok->aaaa());
        }
    }
}






//---------------------------------------------------------------------------
// ClassCheck: Check that all class constructors are ok.
//---------------------------------------------------------------------------

void CheckClass::constructors()
{
    const char pattern_class[] = "class %var% {";

    // Locate class
    const Token *tok1 = Token::findmatch(_tokenizer->tokens(), pattern_class);
    while (tok1)
    {
        const char *className[2];
        className[0] = tok1->strAt(1);
        className[1] = 0;
        const Token *classNameToken = tok1->tokAt(1);

        // TODO: handling of private constructors should be improved.
        bool hasPrivateConstructor = false;
        {
            int indentlevel = 0;
            bool isPrivate = true;
            for (const Token *tok = tok1; tok; tok = tok->next())
            {
                // Indentation
                if (tok->str() == "{")
                    ++indentlevel;

                else if (tok->str() == "}")
                {
                    --indentlevel;
                    if (indentlevel <= 0)
                        break;
                }

                // Parse class contents (indentlevel == 1)..
                if (indentlevel == 1)
                {
                    // What section are we in.. private/non-private
                    if (tok->str() == "private:")
                        isPrivate = true;
                    else if (tok->str() == "protected:" || tok->str() == "public:")
                        isPrivate = false;

                    // Is there a private constructor?
                    else if (isPrivate && Token::simpleMatch(tok, (classNameToken->str() + " (").c_str()))
                    {
                        hasPrivateConstructor = true;
                        break;
                    }
                }
            }
        }

        if (hasPrivateConstructor)
        {
            // TODO: Handle private constructors.
            // Right now to avoid false positives I just bail out
            tok1 = Token::findmatch(tok1->next(), pattern_class);
            continue;
        }

        // Are there a class constructor?
        std::string tempPattern = "%any% " + classNameToken->str() + " (";
        const Token *constructor_token = Token::findmatch(tok1, tempPattern.c_str());
        while (Token::Match(constructor_token, "~"))
            constructor_token = Token::findmatch(constructor_token->next(), tempPattern.c_str());

        // There are no constructor.