CLI: Add -l command line option

cli/cmdlineparser.cpp

@@ -576,6 +576,29 @@ bool CmdLineParser::ParseFromArgs(int argc, const char* const argv[])
                 PrintMessage("cppcheck: argument for '-j' is allowed to be 10000 at max.");
                 return false;
             }
+        } else if (std::strncmp(argv[i], "-l", 2) == 0) {
+            std::string numberString;
+
+            // "-l 3"
+            if (std::strcmp(argv[i], "-l") == 0) {
+                ++i;
+                if (i >= argc || argv[i][0] == '-') {
+                    PrintMessage("cppcheck: argument to '-l' is missing.");
+                    return false;
+                }
+
+                numberString = argv[i];
+            }
+
+            // "-l3"
+            else
+                numberString = argv[i]+2;
+
+            std::istringstream iss(numberString);
+            if (!(iss >> _settings->_loadAverage)) {
+                PrintMessage("cppcheck: argument to '-l' is not a number.");
+                return false;
+            }
         }
 
         // print all possible error messages..
@@ -869,6 +892,9 @@ void CmdLineParser::PrintHelp()
               "                         more comments, like: '// cppcheck-suppress warningId'\n"
               "                         on the lines before the warning to suppress.\n"
               "    -j <jobs>            Start [jobs] threads to do the checking simultaneously.\n"
+              "    -l <load>            Specifies that no new threads should be started if there\n"
+              "                         are other threads running and the load average is at least\n"
+              "                         load (ignored on non UNIX-like systems)\n"
               "    --language=<language>, -x <language>\n"
               "                         Forces cppcheck to check all files as the given\n"
               "                         language. Valid values are: c, c++\n"

cli/threadexecutor.cpp

@@ -138,6 +138,22 @@ int ThreadExecutor::handleRead(int rpipe, unsigned int &result)
     return 1;
 }
 
+bool ThreadExecutor::checkLoadAverage(size_t nchilds)
+{
+    if (!nchilds || !_settings._loadAverage) {
+        return true;
+    }
+
+    double sample;
+    if (getloadavg(&sample, 1) != 1) {
+        // disable load average cheking on getloadavg error
+        return true;
+    } else if (sample < _settings._loadAverage) {
+        return true;
+    }
+    return false;
+}
+
 unsigned int ThreadExecutor::check()
 {
     _fileCount = 0;
@@ -155,7 +171,8 @@ unsigned int ThreadExecutor::check()
     std::map<std::string, std::size_t>::const_iterator i = _files.begin();
     for (;;) {
         // Start a new child
-        if (i != _files.end() && rpipes.size() < _settings._jobs) {
+        size_t nchilds = rpipes.size();
+        if (i != _files.end() && nchilds < _settings._jobs && checkLoadAverage(nchilds)) {
             int pipes[2];
             if (pipe(pipes) == -1) {
                 std::cerr << "pipe() failed: "<< std::strerror(errno) << std::endl;
@@ -211,8 +228,10 @@ unsigned int ThreadExecutor::check()
             FD_ZERO(&rfds);
             for (std::list<int>::const_iterator rp = rpipes.begin(); rp != rpipes.end(); ++rp)
                 FD_SET(*rp, &rfds);
-
-            int r = select(*std::max_element(rpipes.begin(), rpipes.end()) + 1, &rfds, NULL, NULL, NULL);
+            struct timeval tv; // for every second polling of load average condition
+            tv.tv_sec = 1;
+            tv.tv_usec = 0;
+            int r = select(*std::max_element(rpipes.begin(), rpipes.end()) + 1, &rfds, NULL, NULL, &tv);
 
             if (r > 0) {
                 std::list<int>::iterator rp = rpipes.begin();
@@ -320,6 +339,11 @@ void ThreadExecutor::addFileContent(const std::string &path, const std::string &
     _fileContents[path] = content;
 }
 
+bool ThreadExecutor::checkLoadAverage(size_t nchilds)
+{
+    return true;
+}
+
 unsigned int ThreadExecutor::check()
 {
     HANDLE *threadHandles = new HANDLE[_settings._jobs];

cli/threadexecutor.h

@@ -87,6 +87,13 @@ private:
     std::list<std::string> _errorList;
     int _wpipe;
 
+    /**
+     * @brief Check load average condition
+     * @param nchilds - count of currently runned childs
+     * @return true - if new process can be started
+     */
+    bool checkLoadAverage(size_t nchilds);
+
 public:
     /**
      * @return true if support for threads exist.

lib/settings.cpp

@@ -34,6 +34,7 @@ Settings::Settings()
       _relativePaths(false),
       _xml(false), _xml_version(1),
       _jobs(1),
+      _loadAverage(0),
       _exitCode(0),
       _showtime(SHOWTIME_NONE),
       _maxConfigs(12),

lib/settings.h

@@ -115,6 +115,9 @@ public:
         time. Default is 1. (-j N) */
     unsigned int _jobs;
 
+    /** @brief Load average value */
+    unsigned int _loadAverage;
+
     /** @brief If errors are found, this value is returned from main().
         Default value is 0. */
     int _exitCode;