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/*
* 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 "checkstl.h"
#include "executionpath.h"
#include "symboldatabase.h"
#include <sstream>
// Register this check class (by creating a static instance of it)
namespace {
CheckStl instance;
}
// Error message for bad iterator usage..
void CheckStl::invalidIteratorError(const Token *tok, const std::string &iteratorName)
{
reportError(tok, Severity::error, "invalidIterator1", "Invalid iterator: " + iteratorName);
}
void CheckStl::iteratorsError(const Token *tok, const std::string &container1, const std::string &container2)
{
reportError(tok, Severity::error, "iterators", "Same iterator is used with both " + container1 + " and " + container2);
}
// Error message used when dereferencing an iterator that has been erased..
void CheckStl::dereferenceErasedError(const Token *tok, const std::string &itername)
{
reportError(tok, Severity::error, "eraseDereference", "Dereferenced iterator '" + itername + "' has been erased");
}
void CheckStl::iterators()
{
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
// Using same iterator against different containers.
// for (it = foo.begin(); it != bar.end(); ++it)
for (unsigned int iteratorId = 1; iteratorId < symbolDatabase->getVariableListSize(); iteratorId++) {
const Variable* var = symbolDatabase->getVariableFromVarId(iteratorId);
// Check that its an iterator
if (!var || !var->isLocal() || !Token::Match(var->nameToken()->previous(), "iterator|const_iterator|reverse_iterator|const_reverse_iterator"))
continue;
// the validIterator flag says if the iterator has a valid value or not
bool validIterator = Token::Match(var->nameToken()->next(), "[(=]");
const Scope* invalidationScope = 0;
// The container this iterator can be used with
const Variable* container = 0;
const Scope* containerAssignScope = 0;
// When "validatingToken" is reached the validIterator is set to true
const Token* validatingToken = 0;
// Scan through the rest of the code and see if the iterator is
// used against other containers.
for (const Token *tok2 = var->nameToken(); tok2 != var->scope()->classEnd; tok2 = tok2->next()) {
if (invalidationScope && tok2 == invalidationScope->classEnd)
validIterator = true; // Assume that the iterator becomes valid again
if (containerAssignScope && tok2 == containerAssignScope->classEnd)
container = 0; // We don't know which containers might be used with the iterator
if (tok2 == validatingToken)
validIterator = true;
// Is iterator compared against different container?
if (Token::Match(tok2, "%varid% !=|== %var% . end|rend|cend|crend ( )", iteratorId) && container && tok2->tokAt(2)->varId() != container->varId()) {
iteratorsError(tok2, container->name(), tok2->strAt(2));
tok2 = tok2->tokAt(6);
}
// Is the iterator used in a insert/erase operation?
else if (Token::Match(tok2, "%var% . insert|erase ( *| %varid% )|,", iteratorId)) {
const Token* itTok = tok2->tokAt(4);
if (itTok->str() == "*") {
if (tok2->strAt(2) == "insert")
continue;
itTok = itTok->next();
}
// It is bad to insert/erase an invalid iterator
if (!validIterator)
invalidIteratorError(tok2, itTok->str());
// If insert/erase is used on different container then
// report an error
if (container && tok2->varId() != container->varId()) {
// skip error message if container is a set..
const Variable *variableInfo = symbolDatabase->getVariableFromVarId(tok2->varId());
const Token *decltok = variableInfo ? variableInfo->typeStartToken() : NULL;
if (Token::Match(decltok, "const| std :: set"))
continue; // No warning
// skip error message if the iterator is erased/inserted by value
if (itTok->previous()->str() == "*")
continue;
// Show error message, mismatching iterator is used.
iteratorsError(tok2, container->name(), tok2->str());
}
// invalidate the iterator if it is erased
else if (tok2->strAt(2) == std::string("erase")) {
validIterator = false;
invalidationScope = tok2->scope();
}
// skip the operation
tok2 = itTok->next();
}
// it = foo.erase(..
// taking the result of an erase is ok
else if (Token::Match(tok2, "%varid% = %var% . erase (", iteratorId)) {
// the returned iterator is valid
validatingToken = tok2->linkAt(5);
tok2 = tok2->tokAt(5);
}
// Reassign the iterator
else if (Token::Match(tok2, "%varid% = %var% . begin|rbegin|cbegin|crbegin|find (", iteratorId)) {
validatingToken = tok2->linkAt(5);
container = symbolDatabase->getVariableFromVarId(tok2->tokAt(2)->varId());
containerAssignScope = tok2->scope();
// skip ahead
tok2 = tok2->tokAt(5);
}
// Reassign the iterator
else if (Token::Match(tok2, "%varid% = %var%", iteratorId)) {
// Assume that the iterator becomes valid.
// TODO: add checking that checks if the iterator becomes valid or not
validatingToken = Token::findmatch(tok2->tokAt(2), "[;)]");
// skip ahead
tok2 = tok2->tokAt(2);
}
// Dereferencing invalid iterator?
else if (!validIterator && Token::Match(tok2, "* %varid%", iteratorId)) {
dereferenceErasedError(tok2, tok2->strAt(1));
tok2 = tok2->next();
} else if (!validIterator && Token::Match(tok2, "%varid% . %var%", iteratorId)) {
dereferenceErasedError(tok2, tok2->str());
tok2 = tok2->tokAt(2);
}
// bailout handling. Assume that the iterator becomes valid if we see return/break.
// TODO: better handling
else if (Token::Match(tok2, "return|break")) {
validatingToken = Token::findsimplematch(tok2->next(), ";");
}
// bailout handling. Assume that the iterator becomes valid if we see else.
// TODO: better handling
else if (tok2->str() == "else") {
validIterator = true;
}
}
}
}
// Error message for bad iterator usage..
void CheckStl::mismatchingContainersError(const Token *tok)
{
reportError(tok, Severity::error, "mismatchingContainers", "Iterators of mismatching containers are used together.");
}
void CheckStl::mismatchingContainers()
{
static const char* const algorithm2_strings[] = { // func(begin1, end1
"adjacent_find", "all_of", "any_of", "binary_search", "copy", "copy_if", "count", "count_if", "equal", "equal_range",
"find", "find_if", "find_if_not", "for_each", "generate", "is_heap", "is_heap_until", "is_partitioned",
"is_permutation", "is_sorted", "is_sorted_until", "lower_bound", "make_heap", "max_element", "minmax_element",
"min_element", "mismatch", "move", "move_backward", "next_permutation", "none_of", "partition", "partition_copy",
"partition_point", "pop_heap", "prev_permutation", "push_heap", "random_shuffle", "remove", "remove_copy",
"remove_copy_if", "remove_if", "replace", "replace_copy", "replace_copy_if", "replace_if", "reverse", "reverse_copy",
"search_n", "shuffle", "sort", "sort_heap", "stable_partition", "stable_sort", "swap_ranges", "transform", "unique",
"unique_copy", "upper_bound"
};
static const char* const algorithm22_strings[] = { // func(begin1, end1, begin2, end2
"find_end", "find_first_of", "includes", "lexicographical_compare", "merge", "partial_sort_copy",
"search", "set_difference", "set_intersection", "set_symmetric_difference", "set_union"
};
static const char* const algorithm1x1_strings[] = { // func(begin1, x, end1
"inplace_merge", "nth_element", "partial_sort", "rotate", "rotate_copy"
};
static const std::set<std::string> algorithm2(algorithm2_strings, &algorithm2_strings[sizeof(algorithm2_strings) / sizeof(*algorithm2_strings)]);
static const std::set<std::string> algorithm22(algorithm22_strings, &algorithm22_strings[sizeof(algorithm22_strings) / sizeof(*algorithm22_strings)]);
static const std::set<std::string> algorithm1x1(algorithm1x1_strings, &algorithm1x1_strings[sizeof(algorithm1x1_strings) / sizeof(*algorithm1x1_strings)]);
static const std::string iteratorBeginFuncPattern = "begin|cbegin|rbegin|crbegin";
static const std::string iteratorEndFuncPattern = "end|cend|rend|crend";
static const std::string pattern1x1_1 = "%var% . " + iteratorBeginFuncPattern + " ( ) , ";
static const std::string pattern1x1_2 = "%var% . " + iteratorEndFuncPattern + " ( ) ,|)";
static const std::string pattern2 = pattern1x1_1 + pattern1x1_2;
// Check if different containers are used in various calls of standard functions
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (!Token::Match(tok, "std :: %type% ( !!)"))
continue;
const Token* arg1 = tok->tokAt(4);
// TODO: If iterator variables are used instead then there are false negatives.
if (Token::Match(arg1, pattern2.c_str()) && algorithm2.find(tok->strAt(2)) != algorithm2.end()) {
if (arg1->str() != arg1->strAt(6)) {
mismatchingContainersError(arg1);
}
} else if (algorithm22.find(tok->strAt(2)) != algorithm22.end()) {
if (Token::Match(arg1, pattern2.c_str()) && arg1->str() != arg1->strAt(6))
mismatchingContainersError(arg1);
// Find third parameter
const Token* arg3 = arg1;
for (unsigned int i = 0; i < 2 && arg3; i++)
arg3 = arg3->nextArgument();
if (Token::Match(arg3, pattern2.c_str()) && arg3->str() != arg3->strAt(6))
mismatchingContainersError(arg3);
} else if (Token::Match(arg1, pattern1x1_1.c_str()) && algorithm1x1.find(tok->strAt(2)) != algorithm1x1.end()) {
// Find third parameter
const Token *arg3 = arg1->tokAt(6)->nextArgument();
if (Token::Match(arg3, pattern1x1_2.c_str())) {
if (arg1->str() != arg3->str()) {
mismatchingContainersError(arg1);
}
}
}
tok = arg1->linkAt(-1);
}
}
void CheckStl::stlOutOfBounds()
{
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
// Scan through all tokens..
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
const Token* const tok = i->classDef;
// only interested in "for" loops
if (i->type != Scope::eFor || !tok)
continue;
// check if the for loop condition is wrong
for (const Token *tok2 = tok->tokAt(2); tok2 && tok2 != tok->next()->link(); tok2 = tok2->next()) {
if (Token::Match(tok2, "; %var% <= %var% . size ( ) ;")) {
// variable id for loop variable.
unsigned int numId = tok2->next()->varId();
// variable id for the container variable
unsigned int varId = tok2->tokAt(3)->varId();
// Is it a vector?
const Variable *container = symbolDatabase->getVariableFromVarId(varId);
if (!container)
continue;
if (!Token::simpleMatch(container->typeStartToken(), "std :: vector <"))
continue;
for (const Token *tok3 = tok2->tokAt(8); tok3 && tok3 != i->classEnd; tok3 = tok3->next()) {
if (tok3->varId() == varId) {
if (Token::simpleMatch(tok3->next(), ". size ( )"))
break;
else if (Token::Match(tok3->next(), "[ %varid% ]", numId))
stlOutOfBoundsError(tok3, tok3->strAt(2), tok3->str(), false);
else if (Token::Match(tok3->next(), ". at ( %varid% )", numId))
stlOutOfBoundsError(tok3, tok3->strAt(4), tok3->str(), true);
}
}
break;
}
}
}
}
// Error message for bad iterator usage..
void CheckStl::stlOutOfBoundsError(const Token *tok, const std::string &num, const std::string &var, bool at)
{
if (at)
reportError(tok, Severity::error, "stlOutOfBounds", "When " + num + "==" + var + ".size(), " + var + ".at(" + num + ") is out of bounds");
else
reportError(tok, Severity::error, "stlOutOfBounds", "When " + num + "==" + var + ".size(), " + var + "[" + num + "] is out of bounds");
}
/**
* @brief %Check for invalid iterator usage after erase/insert/etc
*/
class EraseCheckLoop : public ExecutionPath {
public:
static void checkScope(CheckStl *checkStl, const Token *it) {
const Token *tok = it;
// Search for the start of the loop body..
while (0 != (tok = tok->next())) {
if (tok->str() == "(")
tok = tok->link();
else if (tok->str() == ")")
break;
// reassigning iterator in loop head
else if (Token::Match(tok, "%var% =") && tok->str() == it->str())
break;
}
if (! Token::simpleMatch(tok, ") {"))
return;
EraseCheckLoop c(checkStl, it->varId());
std::list<ExecutionPath *> checks;
checks.push_back(c.copy());
ExecutionPath::checkScope(tok->tokAt(2), checks);
c.end(checks, tok->link());
while (!checks.empty()) {
delete checks.back();
checks.pop_back();
}
}
private:
/** Startup constructor */
EraseCheckLoop(Check *o, unsigned int varid)
: ExecutionPath(o, varid), eraseToken(0) {
}
/** @brief token where iterator is erased (non-zero => the iterator is invalid) */
const Token *eraseToken;
/** @brief Copy this check. Called from the ExecutionPath baseclass. */
ExecutionPath *copy() {
return new EraseCheckLoop(*this);
}
/** @brief is another execution path equal? */
bool is_equal(const ExecutionPath *e) const {
const EraseCheckLoop *c = static_cast<const EraseCheckLoop *>(e);
return (eraseToken == c->eraseToken);
}
/** @brief no implementation => compiler error if used by accident */
void operator=(const EraseCheckLoop &);
/** @brief parse tokens */
const Token *parse(const Token &tok, std::list<ExecutionPath *> &checks) const {
// bail out if there are assignments. We don't check the assignments properly.
if (Token::Match(&tok, "[;{}] %var% =") || Token::Match(&tok, "= %var% ;")) {
ExecutionPath::bailOutVar(checks, tok.next()->varId());
}
// the loop stops here. Bail out all execution checks that reach
// this statement
if (Token::Match(&tok, "[;{}] break ;")) {
ExecutionPath::bailOut(checks);
}
// erasing iterator => it is invalidated
if (Token::Match(&tok, "erase ( ++|--| %var% )")) {
// check if there is a "it = ints.erase(it);" pattern. if so
// the it is not invalidated.
const Token *token = &tok;
while (NULL != (token = token ? token->previous() : 0)) {
if (Token::Match(token, "[;{}]"))
break;
else if (token->str() == "=")
token = 0;
}
// the it is invalidated by the erase..
if (token) {
// get variable id for the iterator
unsigned int iteratorId = 0;
if (tok.tokAt(2)->isName())
iteratorId = tok.tokAt(2)->varId();
else
iteratorId = tok.tokAt(3)->varId();
// invalidate this iterator in the corresponding checks
for (std::list<ExecutionPath *>::const_iterator it = checks.begin(); it != checks.end(); ++it) {
EraseCheckLoop *c = dynamic_cast<EraseCheckLoop *>(*it);
if (c && c->varId == iteratorId) {
c->eraseToken = &tok;
}
}
}
}
// don't skip any tokens. return the token that we received.
return &tok;
}
/**
* Parse condition. @sa ExecutionPath::parseCondition
* @param tok first token in condition.
* @param checks The execution paths. All execution paths in the list are executed in the current scope
* @return true => bail out all checking
**/
bool parseCondition(const Token &tok, std::list<ExecutionPath *> &checks) {
// no checking of conditions.
(void)tok;
(void)checks;
return false;
}
/** @brief going out of scope - all execution paths end */
void end(const std::list<ExecutionPath *> &checks, const Token * /*tok*/) const {
// check if there are any invalid iterators. If so there is an error.
for (std::list<ExecutionPath *>::const_iterator it = checks.begin(); it != checks.end(); ++it) {
EraseCheckLoop *c = dynamic_cast<EraseCheckLoop *>(*it);
if (c && c->eraseToken) {
CheckStl *checkStl = dynamic_cast<CheckStl *>(c->owner);
if (checkStl) {
checkStl->eraseError(c->eraseToken);
}
}
}
}
};
void CheckStl::erase()
{
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
const Token* const tok = i->classDef;
if (tok && i->type == Scope::eFor) {
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
if (tok2->str() == ";") {
if (Token::Match(tok2, "; %var% !=")) {
// Get declaration token for var..
const Variable *variableInfo = symbolDatabase->getVariableFromVarId(tok2->next()->varId());
const Token *decltok = variableInfo ? variableInfo->typeEndToken() : NULL;
// Is variable an iterator?
bool isIterator = false;
if (decltok && Token::Match(decltok->tokAt(-2), "> :: iterator %varid%", tok2->next()->varId()))
isIterator = true;
// If tok2->next() is an iterator, check scope
if (isIterator)
EraseCheckLoop::checkScope(this, tok2->next());
}
break;
}
if (Token::Match(tok2, "%var% = %var% . begin|rbegin|cbegin|crbegin ( ) ; %var% != %var% . end|rend|cend|crend ( )") &&
tok2->str() == tok2->strAt(8) &&
tok2->strAt(2) == tok2->strAt(10)) {
EraseCheckLoop::checkScope(this, tok2);
break;
}
}
}
else if (i->type == Scope::eWhile && Token::Match(tok, "while ( %var% !=")) {
const unsigned int varid = tok->tokAt(2)->varId();
if (varid > 0 && Token::findmatch(_tokenizer->tokens(), "> :: iterator %varid%", varid))
EraseCheckLoop::checkScope(this, tok->tokAt(2));
}
}
}
// Error message for bad iterator usage..
void CheckStl::eraseError(const Token *tok)
{
reportError(tok, Severity::error, "erase",
"Dangerous iterator usage after erase()-method.\n"
"The iterator is invalid after it has been used in erase() function. "
"Dereferencing or comparing it with another iterator is invalid operation.");
}
void CheckStl::pushback()
{
// Pointer can become invalid after push_back, push_front, reserve or resize..
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "%var% = & %var% [")) {
// Variable id for pointer
const unsigned int pointerId(tok->varId());
// Variable id for the container variable
const unsigned int containerId(tok->tokAt(3)->varId());
if (pointerId == 0 || containerId == 0)
continue;
// Count { , } and parentheses for tok2
int indent = 0;
bool invalidPointer = false;
for (const Token *tok2 = tok; indent >= 0 && tok2; tok2 = tok2->next()) {
if (tok2->str() == "{" || tok2->str() == "(")
++indent;
else if (tok2->str() == "}" || tok2->str() == ")") {
if (indent == 0 && Token::simpleMatch(tok2, ") {"))
tok2 = tok2->next();
else
--indent;
}
// push_back on vector..
if (Token::Match(tok2, "%varid% . push_front|push_back|resize|reserve", containerId))
invalidPointer = true;
// Using invalid pointer..
if (invalidPointer && tok2->varId() == pointerId) {
if (tok2->previous()->str() == "*")
invalidPointerError(tok2, tok2->str());
else if (tok2->next()->str() == ".")
invalidPointerError(tok2, tok2->str());
break;
}
}
}
}
// Iterator becomes invalid after reserve, resize, insert, push_back or push_front..
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (!Token::simpleMatch(tok, "vector <"))
continue;
// if iterator declaration inside for() loop
bool iteratorDeclaredInsideLoop = false;
if ((tok->tokAt(-2) && Token::simpleMatch(tok->tokAt(-2), "for (")) ||
(tok->tokAt(-4) && Token::simpleMatch(tok->tokAt(-4), "for ( std ::"))) {
iteratorDeclaredInsideLoop = true;
}
while (tok && tok->str() != ">")
tok = tok->next();
if (!tok)
break;
if (!Token::Match(tok, "> :: iterator|const_iterator %var% =|;"))
continue;
const unsigned int iteratorid(tok->tokAt(3)->varId());
if (iteratorid == 0)
continue;
if (iteratorDeclaredInsideLoop && tok->strAt(4) == "=") {
// skip "> :: iterator|const_iterator"
tok = tok->tokAt(3);
}
// the variable id for the vector
unsigned int vectorid = 0;
// count { , } and parentheses for tok2
int indent = 0;
std::string invalidIterator;
for (const Token *tok2 = tok; indent >= 0 && tok2; tok2 = tok2->next()) {
if (tok2->str() == "{" || tok2->str() == "(")
++indent;
else if (tok2->str() == "}" || tok2->str() == ")") {
if (indent == 0 && Token::simpleMatch(tok2, ") {"))
tok2 = tok2->next();
else
--indent;
}
// Using push_back or push_front inside a loop..
if (Token::simpleMatch(tok2, "for (")) {
tok2 = tok2->tokAt(2);
}
if (Token::Match(tok2, "%varid% = %var% . begin|rbegin|cbegin|crbegin ( ) ; %varid% != %var% . end|rend|cend|crend ( ) ; ++| %varid% ++| ) {", iteratorid)) {
// variable id for the loop iterator
const unsigned int varId(tok2->tokAt(2)->varId());
if (varId == 0)
continue;
const Token *pushbackTok = 0;
// Count { and } for tok3
const Token *tok3 = tok2->tokAt(20);
for (const Token* const end3 = tok3->linkAt(-1); tok3 != end3; tok3 = tok3->next()) {
if (tok3->str() == "break" || tok3->str() == "return") {
pushbackTok = 0;
break;
} else if (Token::Match(tok3, "%varid% . push_front|push_back|insert|reserve|resize (", varId)) {
pushbackTok = tok3->tokAt(2);
}
}
if (pushbackTok)
invalidIteratorError(pushbackTok, pushbackTok->str(), tok2->str());
}
// Assigning iterator..
if (Token::Match(tok2, "%varid% =", iteratorid)) {
if (Token::Match(tok2->tokAt(2), "%var% . begin|end|rbegin|rend|cbegin|cend|crbegin|crend ( )")) {
vectorid = tok2->tokAt(2)->varId();
tok2 = tok2->tokAt(6);
} else {
vectorid = 0;
}
invalidIterator = "";
}
// push_back on vector..
if (vectorid > 0 && Token::Match(tok2, "%varid% . push_front|push_back|insert|reserve|resize (", vectorid)) {
if (!invalidIterator.empty() && Token::Match(tok2->tokAt(2), "insert ( %varid% ,", iteratorid)) {
invalidIteratorError(tok2, invalidIterator, tok2->strAt(4));
break;
}
invalidIterator = tok2->strAt(2);
tok2 = tok2->linkAt(3);
}
// TODO: instead of bail out for 'else' try to check all execution paths.
else if (tok2->str() == "return" || tok2->str() == "break" || tok2->str() == "else") {
invalidIterator.clear();
}
// Using invalid iterator..
if (!invalidIterator.empty()) {
if (Token::Match(tok2, "++|--|*|+|-|(|,|=|!= %varid%", iteratorid))
invalidIteratorError(tok2, invalidIterator, tok2->strAt(1));
if (Token::Match(tok2, "%varid% ++|--|+|-", iteratorid))
invalidIteratorError(tok2, invalidIterator, tok2->str());
}
}
}
}
// Error message for bad iterator usage..
void CheckStl::invalidIteratorError(const Token *tok, const std::string &func, const std::string &iterator_name)
{
reportError(tok, Severity::error, "invalidIterator2", "After " + func + ", the iterator '" + iterator_name + "' may be invalid");
}
// Error message for bad iterator usage..
void CheckStl::invalidPointerError(const Token *tok, const std::string &pointer_name)
{
reportError(tok, Severity::error, "invalidPointer", "Invalid pointer '" + pointer_name + "' after push_back / push_front");
}
void CheckStl::stlBoundries()
{
// containers (not the vector)..
static const char STL_CONTAINER_LIST[] = "bitset|deque|list|forward_list|map|multimap|multiset|priority_queue|queue|set|stack|hash_map|hash_multimap|hash_set|unordered_map|unordered_multimap|unordered_set|unordered_multiset";
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
// Declaring iterator..
if (tok->str() == "<" && Token::Match(tok->previous(), STL_CONTAINER_LIST)) {
const std::string& container_name(tok->strAt(-1));
if (tok->link())
tok = tok->link();
else
while (tok && tok->str() != ">")
tok = tok->next();
if (!tok)
break;
if (Token::Match(tok, "> :: iterator|const_iterator %var% =|;")) {
const unsigned int iteratorid(tok->tokAt(3)->varId());
if (iteratorid == 0)
continue;
// Using "iterator < ..." is not allowed
const Token* const end = tok->scope()->classEnd;
for (const Token *tok2 = tok; tok2 != end; tok2 = tok2->next()) {
if (Token::Match(tok2, "!!* %varid% <", iteratorid)) {
stlBoundriesError(tok2, container_name);
} else if (Token::Match(tok2, "> %varid% !!.", iteratorid)) {
stlBoundriesError(tok2, container_name);
}
}
}
}
}
}
// Error message for bad boundary usage..
void CheckStl::stlBoundriesError(const Token *tok, const std::string &container_name)
{
reportError(tok, Severity::error, "stlBoundries",
"Dangerous container iterator compare using < operator for " + container_name + "\n"
"Container '" + container_name + "' iterator compared with < operator. "
"Using < operator with container type iterators is dangerous since the order of "
"the items is not guaranteed. One should use != operator instead when comparing "
"iterators in the container.");
}
static bool if_findCompare(const Token * const tokBack)
{
const Token *tok = tokBack;
while (tok && tok->str() == ")") {
tok = tok->next();
if (Token::Match(tok,",|==|!="))
return true;
if (Token::Match(tok, ") !!{") &&
tok->link()->previous() &&
(Token::Match(tok->link()->previous(),",|==|!=") ||
tok->link()->previous()->isName()))
return true;
}
return false;
}
void CheckStl::if_find()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
if ((i->type != Scope::eIf && i->type != Scope::eElseIf && i->type != Scope::eWhile) || !i->classDef)
continue;
const Token* tok = i->classDef->next();
if (tok->str() == "if")
tok = tok->next();
for (const Token* const end = tok->link(); tok != end; tok = (tok == end) ? end : tok->next()) {
if (Token::Match(tok, "&&|(|%oror%"))
tok = tok->next();
else
continue;
while (tok->str() == "(")
tok = tok->next();
if (tok->str() == "!")
tok = tok->next();
if (Token::Match(tok, "%var% . find (")) {
if (if_findCompare(tok->linkAt(3)))
continue;
const unsigned int varid = tok->varId();
const Variable *var = symbolDatabase->getVariableFromVarId(varid);
if (var) {
// Is the variable a std::string or STL container?
const Token * decl = var->typeStartToken();
if (decl->str() == "const")
decl = decl->next();
// stl container
if (Token::Match(decl, "std :: %var% < %type% > &| %varid%", varid))
if_findError(tok, false);
else if (Token::Match(decl, "std :: string &| %varid%", varid))
if_findError(tok, true);
}
}
//check also for vector-like or pointer containers
else if (Token::Match(tok, "* %var%") || Token::Match(tok, "%var% [")) {
// goto %var%
if (tok->str() == "*")
tok = tok->next();
const Token *tok2 = tok->next();
if (tok2->str() == "[")
tok2 = tok2->link()->next();
if (!Token::simpleMatch(tok2, ". find ("))
continue;
if (if_findCompare(tok2->linkAt(2)))
continue;
const unsigned int varid = tok->varId();
const Variable *var = symbolDatabase->getVariableFromVarId(varid);
if (var) {
// Is the variable a std::string or STL container?
const Token * decl = var->typeStartToken();
//jump next to 'const'
if (decl->str() == "const")
decl = decl->next();
//pretty bad limitation.. but it is there in order to avoid
//own implementations of 'find' or any container
if (!Token::simpleMatch(decl, "std ::"))
continue;
decl = decl->tokAt(2);
if (Token::Match(decl, "%var% <")) {
decl = decl->tokAt(2);
//stl-like
if (Token::Match(decl, "std :: %var% < %type% > > &| %varid%", varid))
if_findError(tok, false);
//not stl-like, then let's hope it's a pointer or an array
else if (Token::Match(decl, "%type% >")) {
decl = decl->tokAt(2);
if (Token::Match(decl, "* &| %varid%", varid) ||
Token::Match(decl, "&| %varid% [ ]| %any% ]| ", varid))
if_findError(tok, false);
}
else if (Token::Match(decl, "std :: string > &| %varid%", varid))
if_findError(tok, true);
}
else if (decl && decl->str() == "string") {
decl = decl->next();
if (Token::Match(decl, "* &| %varid%", varid) ||
Token::Match(decl, "&| %varid% [ ]| %any% ]| ", varid))
if_findError(tok, true);
}
}
}
else if (Token::Match(tok, "std :: find|find_if (")) {
// check that result is checked properly
if (!if_findCompare(tok->linkAt(3))) {
if_findError(tok, false);
}
}
}
}
}
void CheckStl::if_findError(const Token *tok, bool str)
{
if (str)
reportError(tok, Severity::performance, "stlIfStrFind",
"Inefficient usage of string::find in condition; string::compare would be faster.\n"
"Either inefficent or wrong usage of string::find. string::compare will be faster if "
"string::find's result is compared with 0, because it will not scan the whole "
"string. If your intention is to check that there are no findings in the string, "
"you should compare with string::npos.");
else
reportError(tok, Severity::warning, "stlIfFind", "Suspicious condition. The result of find is an iterator, but it is not properly checked.");
}
bool CheckStl::isStlContainer(unsigned int varid)
{
// check if this token is defined
if (varid) {
// find where this token is defined
const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(varid);
if (!var)
return false;
// find where this tokens type starts
const Token *type = var->typeStartToken();
// ignore "const"
if (type->str() == "const")
type = type->next();
// discard namespace if supplied
if (Token::simpleMatch(type, "std ::"))
type = type->tokAt(2);
// all possible stl containers as a token
static const char STL_CONTAINER_LIST[] = "array|bitset|deque|list|forward_list|map|multimap|multiset|priority_queue|queue|set|stack|vector|hash_map|hash_multimap|hash_set|unordered_map|unordered_multimap|unordered_set|unordered_multiset|basic_string";
// check if it's an stl template
if (Token::Match(type, STL_CONTAINER_LIST))
return true;
}
return false;
}
void CheckStl::size()
{
if (!_settings->isEnabled("performance"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "%var% . size ( )") ||
Token::Match(tok, "%var% . %var% . size ( )")) {
const Token *tok1 = tok;
unsigned int varid = 0;
// get the variable id
if (tok->strAt(2) != "size") {
tok1 = tok1->tokAt(2);
// found a.b.size(), lookup class/struct variable
const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(tok->varId());
if (var && var->type()) {
// get class/struct variable type
const Scope *type = var->type();
// lookup variable member
std::list<Variable>::const_iterator it;
for (it = type->varlist.begin(); it != type->varlist.end(); ++it) {
if (it->name() == tok1->str()) {
// found member variable, save varid
varid = it->varId();
break;
}
}
}
} else
varid = tok1->varId();
const Token* const end = tok1->tokAt(5);
if (varid) {
// check for comparison to zero
if ((tok->previous() && !tok->previous()->isArithmeticalOp() && Token::Match(end, "==|<=|!=|> 0")) ||
(end->next() && !end->next()->isArithmeticalOp() && Token::Match(tok->tokAt(-2), "0 ==|>=|!=|<"))) {
if (isStlContainer(varid))
sizeError(tok1);
}
// check for using as boolean expression
else if ((Token::Match(tok->tokAt(-2), "if|while (") && end->str() == ")") ||
(tok->previous()->type() == Token::eLogicalOp && Token::Match(end, "&&|)|,|;|%oror%"))) {
if (isStlContainer(varid))
sizeError(tok1);
}
}
}
}
}
void CheckStl::sizeError(const Token *tok)
{
const std::string varname = tok ? tok->str() : std::string("list");
reportError(tok, Severity::performance, "stlSize",
"Possible inefficient checking for '" + varname + "' emptiness.\n"
"Checking for '" + varname + "' emptiness might be inefficient. "
"Using " + varname + ".empty() instead of " + varname + ".size() can be faster. " +
varname + ".size() can take linear time but " + varname + ".empty() is "
"guaranteed to take constant time.");
}
void CheckStl::redundantCondition()
{
const char pattern[] = "if ( %var% . find ( %any% ) != %var% . end|rend|cend|crend ( ) ) "
"{"
" %var% . remove ( %any% ) ;";
const Token *tok = Token::findmatch(_tokenizer->tokens(), pattern);
while (tok) {
// Get tokens for the fields %var% and %any%
const Token *var1 = tok->tokAt(2);
const Token *any1 = var1->tokAt(4);
const Token *var2 = any1->tokAt(3);
const Token *var3 = var2->tokAt(7);
const Token *any2 = var3->tokAt(4);
// Check if all the "%var%" fields are the same and if all the "%any%" are the same..
if (var1->str() == var2->str() &&
var2->str() == var3->str() &&
any1->str() == any2->str()) {
redundantIfRemoveError(tok);
}
tok = Token::findmatch(tok->next(), pattern);
}
}
void CheckStl::redundantIfRemoveError(const Token *tok)
{
reportError(tok, Severity::style, "redundantIfRemove",
"Redundant checking of STL container element.\n"
"Redundant checking of STL container element existence before removing it. "
"The remove method in the STL will not do anything if element doesn't exist");
}
void CheckStl::missingComparison()
{
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
if (i->type != Scope::eFor || !i->classDef)
continue;
for (const Token *tok2 = i->classDef->tokAt(2); tok2 != i->classStart; tok2 = tok2->next()) {
if (tok2->str() == ";")
break;
if (!Token::Match(tok2, "%var% = %var% . begin|rbegin|cbegin|crbegin ( ) ; %var% != %var% . end|rend|cend|crend ( ) ; ++| %var% ++| ) {"))
continue;
// same container
if (tok2->strAt(2) != tok2->strAt(10))
break;
const unsigned int iteratorId(tok2->varId());
if (iteratorId == 0)
break;
// same iterator
if (iteratorId == tok2->tokAt(10)->varId())
break;
// increment iterator
if (!Token::Match(tok2->tokAt(16), "++ %varid% )", iteratorId) &&
!Token::Match(tok2->tokAt(16), "%varid% ++ )", iteratorId)) {
break;
}
const Token *incrementToken = 0;
// Parse loop..
for (const Token *tok3 = i->classStart; tok3 != i->classEnd; tok3 = tok3->next()) {
if (Token::Match(tok3, "%varid% ++", iteratorId))
incrementToken = tok3;
else if (Token::Match(tok3->previous(), "++ %varid% !!.", iteratorId))
incrementToken = tok3;
else if (Token::Match(tok3, "%varid% !=|==", iteratorId))
incrementToken = 0;
else if (tok3->str() == "break" || tok3->str() == "return")
incrementToken = 0;
else if (Token::Match(tok3, "%varid% = %var% . insert ( ++| %varid% ++| ,", iteratorId)) {
// skip insertion..
tok3 = tok3->linkAt(6);
if (!tok3)
break;
}
}
if (incrementToken)
missingComparisonError(incrementToken, tok2->tokAt(16));
}
}
}
void CheckStl::missingComparisonError(const Token *incrementToken1, const Token *incrementToken2)
{
std::ostringstream errmsg;
errmsg << "Missing bounds check for extra iterator increment in loop.\n"
<< "The iterator incrementing is suspicious - it is incremented at line "
<< incrementToken1->linenr() << " and then at line " << incrementToken2->linenr()
<< " The loop might unintentionally skip an element in the container. "
<< "There is no comparison between these increments to prevent that the iterator is "
<< "incremented beyond the end.";
reportError(incrementToken1, Severity::warning, "StlMissingComparison", errmsg.str());
}
static bool isLocal(const SymbolDatabase* symbolDatabase, unsigned int varid)
{
const Variable* var = symbolDatabase->getVariableFromVarId(varid);
return var && !var->isStatic() && var->isLocal();
}
void CheckStl::string_c_str()
{
if (!_tokenizer->isCPP())
return;
const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
// Find all functions that take std::string as argument
std::multimap<std::string, unsigned int> c_strFuncParam;
if (_settings->isEnabled("performance")) {
for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
for (std::list<Function>::const_iterator func = scope->functionList.begin(); func != scope->functionList.end(); ++func) {
if (c_strFuncParam.erase(func->tokenDef->str()) != 0) { // Check if function with this name was already found
c_strFuncParam.insert(std::make_pair(func->tokenDef->str(), 0)); // Disable, because there are overloads. TODO: Handle overloads
continue;
}
unsigned int numpar = 0;
c_strFuncParam.insert(std::make_pair(func->tokenDef->str(), numpar)); // Insert function as dummy, to indicate that there is at least one function with that name
for (const Token* tok = func->argDef->next(); tok != 0; tok = tok->nextArgument()) {
numpar++;
if (Token::Match(tok, "std :: string !!&") || Token::simpleMatch(tok, "const std :: string"))
c_strFuncParam.insert(std::make_pair(func->tokenDef->str(), numpar));
}
}
}
}
// Try to detect common problems when using string::c_str()
for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
if (scope->type != Scope::eFunction || !scope->function)
continue;
enum {charPtr, stdString, stdStringConstRef, Other} returnType = Other;
if (Token::simpleMatch(scope->function->tokenDef->tokAt(-2), "char *"))
returnType = charPtr;
else if (Token::simpleMatch(scope->function->tokenDef->tokAt(-5), "const std :: string &"))
returnType = stdStringConstRef;
else if (Token::Match(scope->function->tokenDef->tokAt(-3), "std :: string !!&"))
returnType = stdString;
for (const Token *tok = scope->classStart; tok && tok != scope->classEnd; tok = tok->next()) {
// Invalid usage..
if (Token::Match(tok, "throw %var% . c_str ( ) ;") && isLocal(symbolDatabase, tok->next()->varId())) {
string_c_strThrowError(tok);
} else if (Token::Match(tok, "[;{}] %var% = %var% . str ( ) . c_str ( ) ;")) {
const Variable* var = symbolDatabase->getVariableFromVarId(tok->next()->varId());
if (var && var->isPointer())
string_c_strError(tok);
} else if (Token::Match(tok, "[;{}] %var% = %var% (") &&
Token::simpleMatch(tok->linkAt(4), ") . c_str ( ) ;") &&
Token::findmatch(_tokenizer->tokens(), ("std :: string " + tok->strAt(3) + " (").c_str())) {
const Variable* var = symbolDatabase->getVariableFromVarId(tok->next()->varId());
if (var && var->isPointer())
string_c_strError(tok);
} else if (Token::Match(tok, "%var% ( !!)") && c_strFuncParam.find(tok->str()) != c_strFuncParam.end() &&
_settings->isEnabled("performance") && !Token::Match(tok->previous(), "::|.") && tok->varId() == 0 && tok->str() != scope->className) { // calling function. TODO: Add support for member functions
std::pair<std::multimap<std::string, unsigned int>::const_iterator, std::multimap<std::string, unsigned int>::const_iterator> range = c_strFuncParam.equal_range(tok->str());
for (std::multimap<std::string, unsigned int>::const_iterator i = range.first; i != range.second; ++i) {
if (i->second == 0)
continue;
const Token* tok2 = tok->tokAt(2);
unsigned int j;
for (j = 0; tok2 && j < i->second-1; j++)
tok2 = tok2->nextArgument();
if (tok2)
tok2 = tok2->nextArgument();
else
break;
if (!tok2 && j == i->second-1)
tok2 = tok->next()->link();
else
tok2 = tok2->previous();
if (tok2 && Token::simpleMatch(tok2->tokAt(-4), ". c_str ( )"))
string_c_strParam(tok, i->second);
}
}
// Using c_str() to get the return value is only dangerous if the function returns a char*
if (returnType == charPtr) {
if (Token::Match(tok, "return %var% . c_str ( ) ;") && isLocal(symbolDatabase, tok->next()->varId())) {
string_c_strError(tok);
} else if (Token::Match(tok, "return %var% . str ( ) . c_str ( ) ;") && isLocal(symbolDatabase, tok->next()->varId())) {
string_c_strError(tok);
} else if (Token::simpleMatch(tok, "return std :: string (") &&
Token::simpleMatch(tok->linkAt(4), ") . c_str ( ) ;")) {
string_c_strError(tok);
} else if (Token::simpleMatch(tok, "return (") &&
Token::simpleMatch(tok->next()->link(), ") . c_str ( ) ;")) {
// Check for "+ localvar" or "+ std::string(" inside the bracket
bool is_implicit_std_string = _settings->inconclusive;
const Token *search_end = tok->next()->link();
for (const Token *search_tok = tok->tokAt(2); search_tok != search_end; search_tok = search_tok->next()) {
if (Token::Match(search_tok, "+ %var%") && isLocal(symbolDatabase, search_tok->next()->varId())) {
is_implicit_std_string = true;
break;
} else if (Token::simpleMatch(search_tok, "+ std :: string (")) {
is_implicit_std_string = true;
break;
}
}
if (is_implicit_std_string)
string_c_strError(tok);
}
}
// Using c_str() to get the return value is redundant if the function returns std::string or const std::string&.
else if ((returnType == stdString || returnType == stdStringConstRef) && _settings->isEnabled("performance")) {
if (tok->str() == "return") {
const Token* tok2 = Token::findsimplematch(tok->next(), ";");
if (Token::simpleMatch(tok2->tokAt(-4), ". c_str ( )"))
string_c_strReturn(tok);
}
}
}
}
}
void CheckStl::string_c_strThrowError(const Token* tok)
{
reportError(tok, Severity::error, "stlcstrthrow", "Dangerous usage of c_str(). The returned value by c_str() is invalid after throw call.\n"
"Dangerous usage of c_str(). The string is destroyed after the c_str() call so the thrown pointer is invalid.");
}
void CheckStl::string_c_strError(const Token* tok)
{
reportError(tok, Severity::error, "stlcstr", "Dangerous usage of c_str(). The returned value by c_str() is invalid after this call.\n"
"Dangerous usage of c_str(). The c_str() return value is only valid until its string is deleted.");
}
void CheckStl::string_c_strReturn(const Token* tok)
{
reportError(tok, Severity::performance, "stlcstrReturn", "Returning the result of c_str() in a function that returns std::string is slow and redundant.\n"
"The conversion from const char* as returned by c_str to std::string creates an unnecessary string copy. Solve that by directly returning the string.");
}
void CheckStl::string_c_strParam(const Token* tok, unsigned int number)
{
std::ostringstream oss;
oss << "Passing the result of c_str() to a function that takes std::string as argument " << number << " is slow and redundant.\n"
"The conversion from const char* as returned by c_str to std::string creates an unnecessary string copy. Solve that by directly passing the string.";
reportError(tok, Severity::performance, "stlcstrParam", oss.str());
}
static bool hasArrayEnd(const Token *tok1)
{
const Token *end = Token::findsimplematch(tok1, ";");
return (end && Token::simpleMatch(end->previous(), "] ;"));
}
static bool hasArrayEndParen(const Token *tok1)
{
const Token *end = Token::findsimplematch(tok1, ";");
return (end && end->previous() &&
Token::simpleMatch(end->tokAt(-2), "] ) ;"));
}
//---------------------------------------------------------------------------
//
//---------------------------------------------------------------------------
void CheckStl::checkAutoPointer()
{
if (!_tokenizer->isCPP())
return;
std::set<unsigned int> autoPtrVarId;
static const char STL_CONTAINER_LIST[] = "array|bitset|deque|list|forward_list|map|multimap|multiset|priority_queue|queue|set|stack|vector|hash_map|hash_multimap|hash_set|unordered_map|unordered_multimap|unordered_set|unordered_multiset|basic_string";
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::simpleMatch(tok, "auto_ptr <")) {
if ((tok->strAt(-1) == "<" && Token::Match(tok->tokAt(-2), STL_CONTAINER_LIST)) ||
(Token::simpleMatch(tok->tokAt(-3), "< std :: auto_ptr") && Token::Match(tok->tokAt(-4), STL_CONTAINER_LIST))) {
autoPointerContainerError(tok);
} else {
const Token *tok2 = tok->tokAt(2);
while (tok2) {
if (Token::Match(tok2, "> %var%")) {
const Token *tok3 = tok2->tokAt(2);
if (Token::Match(tok3, "( new %type%") && hasArrayEndParen(tok3)) {
autoPointerArrayError(tok2->next());
break;
}
while (tok3 && tok3->str() != ";") {
tok3 = tok3->next();
}
if (tok3) {
tok3 = tok3->tokAt(-2);
if (Token::simpleMatch(tok3->previous(), "[ ] )")) {
autoPointerArrayError(tok2->next());
} else if (tok3->varId()) {
const Token *decltok = Token::findmatch(_tokenizer->tokens(), "%varid% = new %type%", tok3->varId());
if (decltok && hasArrayEnd(decltok)) {
autoPointerArrayError(tok2->next());
}
}
if (tok2->next()->varId()) {
autoPtrVarId.insert(tok2->next()->varId());
}
break;
}
}
tok2 = tok2->next();
}
}
} else {
if (Token::Match(tok, "%var% = %var% ;")) {
if (_settings->isEnabled("style")) {
std::set<unsigned int>::const_iterator iter = autoPtrVarId.find(tok->tokAt(2)->varId());
if (iter != autoPtrVarId.end()) {
autoPointerError(tok->tokAt(2));
}
}
} else if ((Token::Match(tok, "%var% = new %type% ") && hasArrayEnd(tok)) ||
(Token::Match(tok, "%var% . reset ( new %type% ") && hasArrayEndParen(tok))) {
std::set<unsigned int>::const_iterator iter = autoPtrVarId.find(tok->varId());
if (iter != autoPtrVarId.end()) {
autoPointerArrayError(tok);
}
}
}
}
}
void CheckStl::autoPointerError(const Token *tok)
{
reportError(tok, Severity::style, "useAutoPointerCopy",
"Copy 'auto_ptr' pointer to another do not create two equal objects since one has lost its ownership of the pointer.\n"
"The auto_ptr has semantics of strict ownership, meaning that the auto_ptr instance is the sole entity responsible for the object's lifetime. If an auto_ptr is copied, the source loses the reference."
);
}
void CheckStl::autoPointerContainerError(const Token *tok)
{
reportError(tok, Severity::error, "useAutoPointerContainer",
"You can randomly lose access to pointers if you store 'auto_ptr' pointers in a container because the copy-semantics of 'auto_ptr' are not compatible with containers.\n"
"An element of container must be able to be copied but 'auto_ptr' does not fulfill this requirement. You should consider to use 'shared_ptr' or 'unique_ptr'. It is suitable for use in containers, because they no longer copy their values, they move them."
);
}
void CheckStl::autoPointerArrayError(const Token *tok)
{
reportError(tok, Severity::error, "useAutoPointerArray",
"Object pointed by an 'auto_ptr' is destroyed using operator 'delete'. You should not use 'auto_ptr' for pointers obtained with operator 'new[]'.\n"
"Object pointed by an 'auto_ptr' is destroyed using operator 'delete'. This means that you should only use 'auto_ptr' for pointers obtained with operator 'new'. This excludes arrays, which are allocated by operator 'new[]' and must be deallocated by operator 'delete[]'."
);
}
void CheckStl::uselessCalls()
{
bool performance = _settings->isEnabled("performance");
bool style = _settings->isEnabled("style");
if (!performance && !style)
return;
const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (tok->varId() && Token::Match(tok, "%var% . compare|find|rfind|find_first_not_of|find_first_of|find_last_not_of|find_last_of ( %var% [,)]") &&
tok->varId() == tok->tokAt(4)->varId() && style) {
uselessCallsReturnValueError(tok->tokAt(4), tok->str(), tok->strAt(2));
} else if (tok->varId() && Token::Match(tok, "%var% . swap ( %var% )") &&
tok->varId() == tok->tokAt(4)->varId() && performance) {
uselessCallsSwapError(tok, tok->str());
} else if (Token::simpleMatch(tok, ". substr (") && performance) {
if (Token::Match(tok->tokAt(3), "0| )"))
uselessCallsSubstrError(tok, false);
else if (tok->strAt(3) == "0" && tok->linkAt(2)->strAt(-1) == "npos") {
if (!symbolDatabase->getVariableFromVarId(tok->linkAt(2)->previous()->varId())) // Make sure that its no variable
uselessCallsSubstrError(tok, false);
} else if (Token::simpleMatch(tok->linkAt(2)->tokAt(-2), ", 0 )"))
uselessCallsSubstrError(tok, true);
} else if (Token::Match(tok, "[{}:;] %var% . empty ( ) ;") && style)
uselessCallsEmptyError(tok->next());
else if (Token::Match(tok, "[{};] std :: remove (") && tok->tokAt(5)->nextArgument())
uselessCallsRemoveError(tok->next());
}
}
void CheckStl::uselessCallsReturnValueError(const Token *tok, const std::string &varname, const std::string &function)
{
std::ostringstream errmsg;
errmsg << "It is inefficient to call '" << varname << "." << function << "(" << varname << ")' as it always returns 0.\n"
<< "The 'std::string::" << function << "()' returns zero when given itself as parameter "
<< "(" << varname << "." << function << "(" << varname << ")). As it is currently the "
<< "code is inefficient. It is also possible either the string searched ('"
<< varname << "') or searched for ('" << varname << "') is wrong/mixed in the code?";
reportError(tok, Severity::warning, "uselessCallsCompare", errmsg.str());
}
void CheckStl::uselessCallsSwapError(const Token *tok, const std::string &varname)
{
std::ostringstream errmsg;
errmsg << "It is inefficient to swap a object with itself by calling '" << varname << ".swap(" << varname << ")'\n"
<< "The 'swap()' function has no logical effect when given itself as parameter "
<< "(" << varname << ".swap(" << varname << ")). As it is currently the "
<< "code is inefficient. It is possible either the object or the parameter is wrong/mixed in the code?";
reportError(tok, Severity::performance, "uselessCallsSwap", errmsg.str());
}
void CheckStl::uselessCallsSubstrError(const Token *tok, bool empty)
{
if (empty)
reportError(tok, Severity::performance, "uselessCallsSubstr", "Useless call of function 'substr' because it returns an empty string.");
else
reportError(tok, Severity::performance, "uselessCallsSubstr", "Useless call of function 'substr' because it returns a copy of the object. Use operator= instead.");
}
void CheckStl::uselessCallsEmptyError(const Token *tok)
{
reportError(tok, Severity::warning, "uselessCallsEmpty", "Useless call of function 'empty()'. Did you intend to call 'clear()' instead?");
}
void CheckStl::uselessCallsRemoveError(const Token *tok)
{
reportError(tok, Severity::warning, "uselessCallsRemove", "Return value of std::remove() ignored. Elements remain in container.\n"
"The return value of std::remove() is ignored. This function returns an iterator to the end of the range containing those elements that should be kept. "
"Elements past new end remain valid but with unspecified values. Use the erase method of the container to delete them.");
}
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