preprocessor.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 "preprocessor.h"
#include "tokenize.h"
#include "token.h"

#include <algorithm>
#include <sstream>
#include <fstream>
#include <iostream>
#include <cstdlib>
#include <cctype>

Preprocessor::Preprocessor()
{

}

static char readChar(std::istream &istr)
{
    char ch = (char)istr.get();

    // Handling of newlines..
    if (ch == '\r')
    {
        ch = '\n';
        if ((char)istr.peek() == '\n')
            (void)istr.get();
    }

    return ch;
}

/** Just read the code into a string. Perform simple cleanup of the code */
std::string Preprocessor::read(std::istream &istr)
{
    // Get filedata from stream..
    bool ignoreSpace = true;

    // need space.. #if( => #if (
    bool needSpace = false;

    // For the error report
    int lineno = 1;

    // handling <backspace><newline>
    // when this is encountered the <backspace><newline> will be "skipped".
    // on the next <newline>, extra newlines will be added
    unsigned int newlines = 0;

    std::ostringstream code;
    for (char ch = readChar(istr); istr.good(); ch = readChar(istr))
    {
        if (ch < 0)
            continue;

        if (ch == '\n')
            ++lineno;

        // Replace assorted special chars with spaces..
        if ((ch != '\n') && (std::isspace(ch) || std::iscntrl(ch)))
            ch = ' ';

        // Skip spaces after ' ' and after '#'
        if (ch == ' ' && ignoreSpace)
            continue;
        ignoreSpace = bool(ch == ' ' || ch == '#' || ch == '/');

        if (needSpace)
        {
            if (ch == '(')
                code << " ";
            else if (! std::isalpha(ch))
                needSpace = false;
        }
        if (ch == '#')
            needSpace = true;

        // Remove comments..
        if (ch == '/')
        {
            char chNext = readChar(istr);

            if (chNext == '/')
            {
                while (istr.good() && ch != '\n')
                    ch = readChar(istr);
                code << "\n";
                ++lineno;
            }

            else if (chNext == '*')
            {
                char chPrev = 0;
                while (istr.good() && (chPrev != '*' || ch != '/'))
                {
                    chPrev = ch;
                    ch = readChar(istr);
                    if (ch == '\n')
                    {
                        code << "\n";
                        ++lineno;
                    }
                }
            }

            else
            {
                if (chNext == '\n')
                    ++lineno;
                code << std::string(1, ch) << std::string(1, chNext);
            }
        }

        // String or char constants..
        else if (ch == '\"' || ch == '\'')
        {
            code << std::string(1, ch);
            char chNext;
            do
            {
                chNext = (char)istr.get();
                if (chNext == '\\')
                {
                    char chSeq = readChar(istr);
                    if (chSeq == '\n')
                        ++newlines;
                    else
                    {
                        code << std::string(1, chNext);
                        code << std::string(1, chSeq);
                    }
                }
                else
                    code << std::string(1, chNext);
            }
            while (istr.good() && chNext != ch);
        }
        // <backspace><newline>..
        else if (ch == '\\')
        {
            char chNext = (char)istr.peek();
            if (chNext == '\n' || chNext == '\r')
            {
                ++newlines;
                (void)readChar(istr);   // Skip the "<backspace><newline>"
            }
            else
                code << "\\";
        }

        // Just some code..
        else
        {
            code << std::string(1, ch);

            // if there has been <backspace><newline> sequences, add extra newlines..
            if (ch == '\n' && newlines > 0)
            {
                code << std::string(newlines, '\n');
                newlines = 0;
            }
        }
    }

    return code.str();
}

void Preprocessor::preprocess(std::istream &istr, std::map<std::string, std::string> &result, const std::string &filename, const std::list<std::string> &includePaths)
{
    std::list<std::string> configs;
    std::string data;
    preprocess(istr, data, configs, filename, includePaths);
    for (std::list<std::string>::const_iterator it = configs.begin(); it != configs.end(); ++it)
        result[ *it ] = Preprocessor::getcode(data, *it);
}

std::string Preprocessor::removeSpaceNearNL(const std::string &str)
{
    std::string tmp;
    int prev = -1;
    for (unsigned int i = 0; i < str.size(); i++)
    {
        if (str[i] == ' ' &&
            ((i > 0 && tmp[prev] == '\n') ||
             (i + 1 < str.size() && str[i+1] == '\n')
            )
           )
        {
            // Ignore space that has new line in either side of it
        }
        else
        {
            tmp.append(1, str[i]);
            ++prev;
        }
    }

    return tmp;
}

std::string Preprocessor::replaceIfDefined(const std::string &str)
{
    std::string ret(str);
    std::string::size_type pos = 0;
    while ((pos = ret.find("#if defined(", pos)) != std::string::npos)
    {
        std::string::size_type pos2 = ret.find(")", pos + 9);
        if (pos2 > ret.length() - 1)
            break;
        if (ret[pos2+1] == '\n')
        {
            ret.erase(pos2, 1);
            ret.erase(pos + 3, 9);
            ret.insert(pos + 3, "def ");
        }
        ++pos;
    }

    return ret;
}

void Preprocessor::preprocess(std::istream &istr, std::string &processedFile, std::list<std::string> &resultConfigurations, const std::string &filename, const std::list<std::string> &includePaths)
{
    processedFile = read(istr);

    // Replace all tabs with spaces..
    std::replace(processedFile.begin(), processedFile.end(), '\t', ' ');

    // Remove all indentation..
    if (!processedFile.empty() && processedFile[0] == ' ')
        processedFile.erase(0, processedFile.find_first_not_of(" "));

    // Remove space characters that are after or before new line character
    processedFile = removeSpaceNearNL(processedFile);

    handleIncludes(processedFile, filename, includePaths);

    processedFile = replaceIfDefined(processedFile);

    // Get all possible configurations..
    resultConfigurations = getcfgs(processedFile);
}



// Get the DEF in this line: "#ifdef DEF"
std::string Preprocessor::getdef(std::string line, bool def)
{
    // If def is true, the line must start with "#ifdef"
    if (def && line.find("#ifdef ") != 0 && line.find("#if ") != 0 && line.find("#elif ") != 0)
    {
        return "";
    }

    // If def is false, the line must start with "#ifndef"
    if (!def && line.find("#ifndef ") != 0)
    {
        return "";
    }

    // Remove the "#ifdef" or "#ifndef"
    line.erase(0, line.find(" "));

    // Remove all spaces.
    while (line.find(" ") != std::string::npos)
        line.erase(line.find(" "), 1);

    // The remaining string is our result.
    return line;
}



std::list<std::string> Preprocessor::getcfgs(const std::string &filedata)
{
    std::list<std::string> ret;
    ret.push_back("");

    std::list<std::string> deflist;

    // How deep into included files are we currently parsing?
    // 0=>Source file, 1=>Included by source file, 2=>included by header that was included by source file, etc
    int filelevel = 0;

    std::istringstream istr(filedata);
    std::string line;
    while (getline(istr, line))
    {
        if (line.substr(0, 6) == "#file ")
        {
            ++filelevel;
            continue;
        }

        else if (line == "#endfile")
        {
            if (filelevel > 0)
                --filelevel;
            continue;
        }

        if (filelevel > 0)
            continue;

        std::string def = getdef(line, true) + getdef(line, false);
        if (!def.empty())
        {
            if (! deflist.empty() && line.find("#elif ") == 0)
                deflist.pop_back();
            deflist.push_back(def);
            def = "";
            for (std::list<std::string>::const_iterator it = deflist.begin(); it != deflist.end(); ++it)
            {
                if (*it == "0")
                    break;
                if (*it == "1")
                    continue;
                if (! def.empty())
                    def += ";";
                def += *it;
            }

            if (std::find(ret.begin(), ret.end(), def) == ret.end())
                ret.push_back(def);
        }

        if (line.find("#else") == 0 && ! deflist.empty())
        {
            std::string def((deflist.back() == "1") ? "0" : "1");
            deflist.pop_back();
            deflist.push_back(def);
        }

        if (line.find("#endif") == 0 && ! deflist.empty())
            deflist.pop_back();
    }

    return ret;
}



bool Preprocessor::match_cfg_def(std::string cfg, const std::string &def)
{
    if (def == "0")
        return false;

    if (def == "1")
        return true;

    if (cfg.empty())
        return false;

    while (! cfg.empty())
    {
        if (cfg.find(";") == std::string::npos)
            return bool(cfg == def);
        std::string _cfg = cfg.substr(0, cfg.find(";"));
        if (_cfg == def)
            return true;
        cfg.erase(0, cfg.find(";") + 1);
    }

    return false;
}


std::string Preprocessor::getcode(const std::string &filedata, std::string cfg)
{
    std::ostringstream ret;

    bool match = true;
    std::list<bool> matching_ifdef;
    std::list<bool> matched_ifdef;

    std::istringstream istr(filedata);
    std::string line;
    while (getline(istr, line))
    {
        std::string def = getdef(line, true);
        std::string ndef = getdef(line, false);

        if (line.find("#elif ") == 0)
        {
            if (matched_ifdef.back())
            {
                matching_ifdef.back() = false;
            }
            else
            {
                if (match_cfg_def(cfg, def))
                {
                    matching_ifdef.back() = true;
                    matched_ifdef.back() = true;
                }
            }
        }

        else if (! def.empty())
        {
            matching_ifdef.push_back(match_cfg_def(cfg, def));
            matched_ifdef.push_back(matching_ifdef.back());
        }

        else if (! ndef.empty())
        {
            matching_ifdef.push_back(! match_cfg_def(cfg, ndef));
            matched_ifdef.push_back(matching_ifdef.back());
        }

        else if (line == "#else")
        {
            if (! matched_ifdef.empty())
                matching_ifdef.back() = ! matched_ifdef.back();
        }

        else if (line == "#endif")
        {
            if (! matched_ifdef.empty())
                matched_ifdef.pop_back();
            if (! matching_ifdef.empty())
                matching_ifdef.pop_back();
        }

        if (!line.empty() && line[0] == '#')
        {
            match = true;
            for (std::list<bool>::const_iterator it = matching_ifdef.begin(); it != matching_ifdef.end(); ++it)
                match &= bool(*it);