cppcheck/lib/checkinternal.cpp

/*
 * Cppcheck - A tool for static C/C++ code analysis
 * Copyright (C) 2007-2015 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/>.
 */

#ifdef CHECK_INTERNAL

#include "checkinternal.h"
#include "symboldatabase.h"
#include <string>
#include <set>
#include <cstring>
#include <cctype>

// Register this check class (by creating a static instance of it).
// Disabled in release builds
namespace {
    CheckInternal instance;
}

void CheckInternal::checkTokenMatchPatterns()
{
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
        if (!Token::simpleMatch(tok, "Token :: Match (") && !Token::simpleMatch(tok, "Token :: findmatch ("))
            continue;

        const std::string& funcname = tok->strAt(2);

        // Get pattern string
        const Token *pattern_tok = tok->tokAt(4)->nextArgument();
        if (!pattern_tok || pattern_tok->type() != Token::eString)
            continue;

        const std::string pattern = pattern_tok->strValue();
        if (pattern.empty()) {
            simplePatternError(tok, pattern, funcname);
            continue;
        }

        if (pattern.find("||") != std::string::npos || pattern.find(" | ") != std::string::npos || pattern[0] == '|' || (pattern[pattern.length() - 1] == '|' && pattern[pattern.length() - 2] == ' '))
            orInComplexPattern(tok, pattern, funcname);

        // Check for signs of complex patterns
        if (pattern.find_first_of("[|") != std::string::npos)
            continue;
        else if (pattern.find("!!") != std::string::npos)
            continue;

        bool complex = false;
        size_t index = pattern.find('%');
        while (index != std::string::npos) {
            if (pattern.length() <= index + 2) {
                complex = true;
                break;
            }
            if (pattern[index + 1] == 'o' && pattern[index + 2] == 'r') // %or% or %oror%
                index = pattern.find('%', index + 1);
            else {
                complex = true;
                break;
            }
            index = pattern.find('%', index+1);
        }
        if (!complex)
            simplePatternError(tok, pattern, funcname);
    }
}

void CheckInternal::checkTokenSimpleMatchPatterns()
{
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
        if (!Token::simpleMatch(tok, "Token :: simpleMatch (") && !Token::simpleMatch(tok, "Token :: findsimplematch ("))
            continue;

        const std::string& funcname = tok->strAt(2);

        // Get pattern string
        const Token *pattern_tok = tok->tokAt(4)->nextArgument();
        if (!pattern_tok || pattern_tok->type() != Token::eString)
            continue;

        const std::string pattern = pattern_tok->strValue();
        if (pattern.empty()) {
            complexPatternError(tok, pattern, funcname);
            continue;
        }

        // Check for [xyz] usage - but exclude standalone square brackets
        unsigned int char_count = 0;
        for (std::string::size_type pos = 0; pos < pattern.size(); ++pos) {
            char c = pattern[pos];

            if (c == ' ') {
                char_count = 0;
            } else if (c == ']') {
                if (char_count > 0) {
                    complexPatternError(tok, pattern, funcname);
                    continue;
                }
            } else {
                ++char_count;
            }
        }

        // Check | usage: Count characters before the symbol
        char_count = 0;
        for (std::string::size_type pos = 0; pos < pattern.size(); ++pos) {
            char c = pattern[pos];

            if (c == ' ') {
                char_count = 0;
            } else if (c == '|') {
                if (char_count > 0) {
                    complexPatternError(tok, pattern, funcname);
                    continue;
                }
            } else {
                ++char_count;
            }
        }

        // Check for real errors
        if (pattern.length() > 1) {
            for (size_t i = 0; i < pattern.length() - 1; i++) {
                if (pattern[i] == '%' && pattern[i + 1] != ' ')
                    complexPatternError(tok, pattern, funcname);
                else if (pattern[i] == '!' && pattern[i + 1] == '!')
                    complexPatternError(tok, pattern, funcname);
            }
        }
    }
}

void CheckInternal::checkMissingPercentCharacter()
{
    static std::set<std::string> magics;
    if (magics.empty()) {
        magics.insert("%any%");
        magics.insert("%bool%");
        magics.insert("%char%");
        magics.insert("%comp%");
        magics.insert("%num%");
        magics.insert("%op%");
        magics.insert("%cop%");
        magics.insert("%or%");
        magics.insert("%oror%");
        magics.insert("%str%");
        magics.insert("%type%");
        magics.insert("%name%");
        magics.insert("%varid%");
    }

    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
        if (!Token::simpleMatch(tok, "Token :: Match (") && !Token::simpleMatch(tok, "Token :: findmatch ("))
            continue;

        const std::string& funcname = tok->strAt(2);

        // Get pattern string
        const Token *pattern_tok = tok->tokAt(4)->nextArgument();
        if (!pattern_tok || pattern_tok->type() != Token::eString)
            continue;

        const std::string pattern = pattern_tok->strValue();

        std::set<std::string>::const_iterator magic, magics_end = magics.end();
        for (magic = magics.begin(); magic != magics_end; ++magic) {
            const std::string broken_magic = (*magic).substr(0, (*magic).size()-1);

            std::string::size_type pos = 0;
            while ((pos = pattern.find(broken_magic, pos)) != std::string::npos) {
                // Check if it's the full pattern
                if (pattern.find(*magic, pos) != pos) {
                    // Known whitelist of substrings
                    if ((broken_magic == "%var" && pattern.find("%varid%", pos) == pos) ||
                        (broken_magic == "%or" && pattern.find("%oror%", pos) == pos)) {
                        ++pos;
                        continue;
                    }

                    missingPercentCharacterError(tok, pattern, funcname);
                }

                ++pos;
            }
        }
    }
}

void CheckInternal::checkUnknownPattern()
{
    static std::set<std::string> knownPatterns;
    if (knownPatterns.empty()) {
        knownPatterns.insert("%any%");
        knownPatterns.insert("%bool%");
        knownPatterns.insert("%char%");
        knownPatterns.insert("%comp%");
        knownPatterns.insert("%name%");
        knownPatterns.insert("%num%");
        knownPatterns.insert("%op%");
        knownPatterns.insert("%cop%");
        knownPatterns.insert("%or%");
        knownPatterns.insert("%oror%");
        knownPatterns.insert("%str%");
        knownPatterns.insert("%type%");
        knownPatterns.insert("%var%");
        knownPatterns.insert("%varid%");
    }

    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
        if (!Token::simpleMatch(tok, "Token :: Match (") && !Token::simpleMatch(tok, "Token :: findmatch ("))
            continue;

        // Get pattern string
        const Token *pattern_tok = tok->tokAt(4)->nextArgument();
        if (!pattern_tok || pattern_tok->type() != Token::eString)
            continue;

        const std::string pattern = pattern_tok->strValue();
        bool inBrackets = false;

        for (std::string::size_type i = 0; i < pattern.length()-1; i++) {
            if (pattern[i] == '[' && (i == 0 || pattern[i-1] == ' '))
                inBrackets = true;
            else if (pattern[i] == ']')
                inBrackets = false;
            else if (pattern[i] == '%' && pattern[i+1] != ' ' && pattern[i+1] != '|' && !inBrackets) {
                std::string::size_type end = pattern.find('%', i+1);
                if (end != std::string::npos) {
                    std::string s = pattern.substr(i, end-i+1);
                    if (knownPatterns.find(s) == knownPatterns.end())
                        unknownPatternError(tok, s);
                }
            }
        }
    }
}

void CheckInternal::checkRedundantNextPrevious()
{
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
        if (Token::Match(tok, ". previous ( ) . next|tokAt|strAt|linkAt (") || Token::Match(tok, ". next ( ) . previous|tokAt|strAt|linkAt (") ||
            (Token::simpleMatch(tok, ". tokAt (") && Token::Match(tok->linkAt(2), ") . previous|next|tokAt|strAt|linkAt|str|link ("))) {
            const std::string& func1 = tok->strAt(1);
            const std::string& func2 = tok->linkAt(2)->strAt(2);

            if ((func2 == "previous" || func2 == "next" || func2 == "str" || func2 == "link") && tok->linkAt(2)->strAt(4) != ")")
                continue;

            redundantNextPreviousError(tok, func1, func2);
        } else if (Token::Match(tok, ". next|previous ( ) . next|previous ( ) . next|previous|linkAt|strAt|link|str (")) {
            const std::string& func1 = tok->strAt(1);
            const std::string& func2 = tok->strAt(9);

            if ((func2 == "previous" || func2 == "next" || func2 == "str" || func2 == "link") && tok->strAt(11) != ")")
                continue;

            redundantNextPreviousError(tok, func1, func2);
        }
    }
}

void CheckInternal::checkExtraWhitespace()
{
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
        if (!Token::simpleMatch(tok, "Token :: simpleMatch (") &&
            !Token::simpleMatch(tok, "Token :: findsimplematch (") &&
            !Token::simpleMatch(tok, "Token :: Match (") &&
            !Token::simpleMatch(tok, "Token :: findmatch ("))
            continue;

        const std::string& funcname = tok->strAt(2);

        // Get pattern string
        const Token *pattern_tok = tok->tokAt(4)->nextArgument();
        if (!pattern_tok || pattern_tok->type() != Token::eString)
            continue;

        const std::string pattern = pattern_tok->strValue();
        if (!pattern.empty() && (pattern[0] == ' ' || *pattern.rbegin() == ' '))
            extraWhitespaceError(tok, pattern, funcname);

        // two whitespaces or more
        if (pattern.find("  ") != std::string::npos)
            extraWhitespaceError(tok, pattern, funcname);
    }
}

void CheckInternal::multiComparePatternError(const Token* tok, const std::string& pattern, const std::string &funcname)
{
    reportError(tok, Severity::error, "multiComparePatternError",
                "Bad multicompare pattern (a %cmd% must be first unless it is %or%,%op%,%cop%,%name%,%oror%) inside Token::" + funcname + "() call: \"" + pattern + "\""
               );
}

void CheckInternal::simplePatternError(const Token* tok, const std::string& pattern, const std::string &funcname)
{
    reportError(tok, Severity::warning, "simplePatternError",
                "Found simple pattern inside Token::" + funcname + "() call: \"" + pattern + "\""
               );
}

void CheckInternal::complexPatternError(const Token* tok, const std::string& pattern, const std::string &funcname)
{
    reportError(tok, Severity::error, "complexPatternError",
                "Found complex pattern inside Token::" + funcname + "() call: \"" + pattern + "\""
               );
}

void CheckInternal::missingPercentCharacterError(const Token* tok, const std::string& pattern, const std::string& funcname)
{
    reportError(tok, Severity::error, "missingPercentCharacter",
                "Missing percent end character in Token::" + funcname + "() pattern: \"" + pattern + "\""
               );
}

void CheckInternal::unknownPatternError(const Token* tok, const std::string& pattern)
{
    reportError(tok, Severity::error, "unknownPattern",
                "Unknown pattern used: \"" + pattern + "\"");
}

void CheckInternal::redundantNextPreviousError(const Token* tok, const std::string& func1, const std::string& func2)
{
    reportError(tok, Severity::style, "redundantNextPrevious",
                "Call to 'Token::" + func1 + "()' followed by 'Token::" + func2 + "()' can be simplified.");
}

void CheckInternal::orInComplexPattern(const Token* tok, const std::string& pattern, const std::string &funcname)
{
    reportError(tok, Severity::error, "orInComplexPattern",
                "Token::" + funcname + "() pattern \"" + pattern + "\" contains \"||\" or \"|\". Replace it by \"%oror%\" or \"%or%\".");
}

void CheckInternal::extraWhitespaceError(const Token* tok, const std::string& pattern, const std::string &funcname)
{
    reportError(tok, Severity::warning, "extraWhitespaceError",
                "Found extra whitespace inside Token::" + funcname + "() call: \"" + pattern + "\""
               );
}

#endif // #ifdef CHECK_INTERNAL