cppcheck/lib/templatesimplifier.cpp

/*
 * Cppcheck - A tool for static C/C++ code analysis
 * Copyright (C) 2007-2012 Daniel Marjamäki and Cppcheck team.
 *
 * 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 "templatesimplifier.h"
#include "token.h"
#include <sstream>
#include <set>
#include <string>

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

TemplateSimplifier::TemplateSimplifier()
{
}

TemplateSimplifier::~TemplateSimplifier()
{
}

void TemplateSimplifier::cleanupAfterSimplify(Token *tokens)
{
    bool goback = false;
    for (Token *tok = tokens; tok; tok = tok->next()) {
        if (goback) {
            tok = tok->previous();
            goback = false;
        }
        if (tok->str() == "(")
            tok = tok->link();

        else if (Token::Match(tok, "%type% <") &&
                 (!tok->previous() || tok->previous()->str() == ";")) {
            const Token *tok2 = tok->tokAt(2);
            std::string type;
            while (Token::Match(tok2, "%type% ,") || Token::Match(tok2, "%num% ,")) {
                type += tok2->str() + ",";
                tok2 = tok2->tokAt(2);
            }
            if (Token::Match(tok2, "%type% > (") || Token::Match(tok2, "%num% > (")) {
                type += tok2->str();
                tok->str(tok->str() + "<" + type + ">");
                Token::eraseTokens(tok, tok2->tokAt(2));
                if (tok == tokens)
                    goback = true;
            }
        }
    }
}


const Token* TemplateSimplifier::hasComplicatedSyntaxErrorsInTemplates(Token *tokens)
{
    // check for more complicated syntax errors when using templates..
    for (const Token *tok = tokens; tok; tok = tok->next()) {
        // skip executing scopes..
        if (Token::Match(tok, ") const| {") || Token::Match(tok, "[,=] {")) {
            while (tok->str() != "{")
                tok = tok->next();
            tok = tok->link();
        }

        // skip executing scopes (ticket #1984)..
        if (Token::simpleMatch(tok, "; {"))
            tok = tok->next()->link();

        // skip executing scopes (ticket #3183)..
        if (Token::simpleMatch(tok, "( {"))
            tok = tok->next()->link();

        // skip executing scopes (ticket #1985)..
        if (Token::simpleMatch(tok, "try {")) {
            tok = tok->next()->link();
            while (Token::simpleMatch(tok, "} catch (")) {
                tok = tok->linkAt(2);
                if (Token::simpleMatch(tok, ") {"))
                    tok = tok->next()->link();
            }
        }

        // not start of statement?
        if (tok->previous() && !Token::Match(tok, "[;{}]"))
            continue;

        // skip starting tokens.. ;;; typedef typename foo::bar::..
        while (Token::Match(tok, "[;{}]"))
            tok = tok->next();
        while (Token::Match(tok, "typedef|typename"))
            tok = tok->next();
        while (Token::Match(tok, "%type% ::"))
            tok = tok->tokAt(2);
        if (!tok)
            break;

        // template variable or type..
        if (Token::Match(tok, "%type% <")) {
            // these are used types..
            std::set<std::string> usedtypes;

            // parse this statement and see if the '<' and '>' are matching
            unsigned int level = 0;
            for (const Token *tok2 = tok; tok2 && !Token::Match(tok2, "[;{}]"); tok2 = tok2->next()) {
                if (tok2->str() == "(")
                    tok2 = tok2->link();
                else if (tok2->str() == "<") {
                    bool inclevel = false;
                    if (Token::simpleMatch(tok2->previous(), "operator <"))
                        ;
                    else if (level == 0)
                        inclevel = true;
                    else if (tok2->next() && tok2->next()->isStandardType())
                        inclevel = true;
                    else if (Token::simpleMatch(tok2, "< typename"))
                        inclevel = true;
                    else if (Token::Match(tok2->tokAt(-2), "<|, %type% <") && usedtypes.find(tok2->previous()->str()) != usedtypes.end())
                        inclevel = true;
                    else if (Token::Match(tok2, "< %type%") && usedtypes.find(tok2->next()->str()) != usedtypes.end())
                        inclevel = true;
                    else if (Token::Match(tok2, "< %type%")) {
                        // is the next token a type and not a variable/constant?
                        // assume it's a type if there comes another "<"
                        const Token *tok3 = tok2->next();
                        while (Token::Match(tok3, "%type% ::"))
                            tok3 = tok3->tokAt(2);
                        if (Token::Match(tok3, "%type% <"))
                            inclevel = true;
                    }

                    if (inclevel) {
                        ++level;
                        if (Token::Match(tok2->tokAt(-2), "<|, %type% <"))
                            usedtypes.insert(tok2->previous()->str());
                    }
                } else if (tok2->str() == ">") {
                    if (level > 0)
                        --level;
                } else if (tok2->str() == ">>") {
                    if (level > 0)
                        --level;
                    if (level > 0)
                        --level;
                }
            }
            if (level > 0) {
//                syntaxError(tok);
                return tok;
            }
        }
    }

    return 0;
}

unsigned int TemplateSimplifier::templateParameters(const Token *tok)
{
    unsigned int numberOfParameters = 0;

    if (!tok)
        return 0;
    if (tok->str() != "<")
        return 0;
    tok = tok->next();

    unsigned int level = 0;

    while (tok) {
        if (level == 0)
            ++numberOfParameters;

        // skip std::
        while (Token::Match(tok, "%var% ::"))
            tok = tok->tokAt(2);
        if (!tok)
            return 0;

        // num/type ..
        if (!tok->isNumber() && !tok->isName())
            return 0;
        tok = tok->next();

        // optional "*"
        if (tok->str() == "*")
            tok = tok->next();

        // inner template
        if (tok->str() == "<") {
            ++level;
            tok = tok->next();
            continue;
        }

        // ,/>
        while (tok->str() == ">") {
            if (level == 0)
                return numberOfParameters;
            --level;
            tok = tok->next();
        }
        if (tok->str() != ",")
            break;
        tok = tok->next();
    }
    return 0;
}

void TemplateSimplifier::removeTemplates(Token *tok)
{
    bool goback = false;
    for (; tok; tok = tok->next()) {
        if (goback) {
            tok = tok->previous();
            goback = false;
        }
        if (!Token::simpleMatch(tok, "template <"))
            continue;

        for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) {

            if (tok2->str() == "(") {
                tok2 = tok2->link();
            }

            else if (tok2->str() == "{") {
                tok2 = tok2->link()->next();
                Token::eraseTokens(tok, tok2);
                if (tok2 && tok2->str() == ";" && tok2->next())
                    tok->deleteNext();
                tok->deleteThis();
                goback = true;
                break;
            } else if (tok2->str() == "}") {  // garbage code! (#3449)
                Token::eraseTokens(tok,tok2);
                tok->deleteThis();
                break;
            }
            // don't remove constructor
            if (tok2->str() == "explicit") {
                Token::eraseTokens(tok, tok2);
                tok->deleteThis();
                goback = true;
                break;
            }

            if (tok2->str() == ";") {
                tok2 = tok2->next();
                Token::eraseTokens(tok, tok2);
                tok->deleteThis();
                goback = true;
                break;
            }

            if (Token::Match(tok2, ">|>> class|struct %var% [,)]")) {
                tok2 = tok2->next();
                Token::eraseTokens(tok, tok2);
                tok->deleteThis();
                goback = true;
                break;
            }
        }
    }
}


std::set<std::string> TemplateSimplifier::simplifyTemplatesExpandSpecialized(Token *tokens)
{
    std::set<std::string> expandedtemplates;

    // Locate specialized templates..
    for (Token *tok = tokens; tok; tok = tok->next()) {
        if (tok->str() != "template")
            continue;
        if (!Token::simpleMatch(tok->next(), "< >"))
            continue;

        // what kind of template is this?
        Token *tok2 = tok->tokAt(3);
        while (tok2 && (tok2->isName() || tok2->str() == "*"))
            tok2 = tok2->next();

        if (!TemplateSimplifier::templateParameters(tok2))
            continue;

        // unknown template.. bail out
        if (!tok2->previous()->isName())
            continue;

        tok2 = tok2->previous();
        std::string s;
        {
            std::ostringstream ostr;
            const Token *tok3 = tok2;
            for (tok3 = tok2; tok3 && tok3->str() != ">"; tok3 = tok3->next()) {
                if (tok3 != tok2)
                    ostr << " ";
                ostr << tok3->str();
            }
            if (!Token::simpleMatch(tok3, "> ("))
                continue;
            s = ostr.str();
        }

        // save search pattern..
        const std::string pattern(s + " > (");

        // remove spaces to create new name
        while (s.find(" ") != std::string::npos)
            s.erase(s.find(" "), 1);
        const std::string name(s + ">");
        expandedtemplates.insert(name);

        // Rename template..
        Token::eraseTokens(tok2, Token::findsimplematch(tok2, "("));
        tok2->str(name);

        // delete the "template < >"
        tok->deleteNext(2);
        tok->deleteThis();

        // Use this special template in the code..
        while (NULL != (tok2 = const_cast<Token *>(Token::findmatch(tok2, pattern.c_str())))) {
            Token::eraseTokens(tok2, Token::findsimplematch(tok2, "("));
            tok2->str(name);
        }
    }

    return expandedtemplates;
}