Fixed #1650 (Cppcheck deadlock)

http://sourceforge.net/apps/trac/cppcheck/ticket/1650

cli/threadexecutor.cpp

@@ -27,6 +27,7 @@
 #include <cstdlib>
 #include <cstring>
 #include <cstdio>
+#include <errno.h>
 #endif
 
 ThreadExecutor::ThreadExecutor(const std::vector<std::string> &filenames, const Settings &settings, ErrorLogger &errorLogger)
@@ -51,12 +52,15 @@ void ThreadExecutor::addFileContent(const std::string &path, const std::string &
 
 #if (defined(__GNUC__) || defined(__sun)) && !defined(__MINGW32__)
 
-bool ThreadExecutor::handleRead(unsigned int &result)
+int ThreadExecutor::handleRead(unsigned int &result)
 {
     char type = 0;
     if (read(_pipe[0], &type, 1) <= 0)
     {
-        return false;
+        if( errno == EAGAIN )
+            return 0;
+
+        return -1;
     }
 
     if (type != '1' && type != '2' && type != '3')
@@ -104,10 +108,12 @@ bool ThreadExecutor::handleRead(unsigned int &result)
         iss >> fileResult;
         result += fileResult;
         _errorLogger.reportStatus(_fileCount, _filenames.size());
+        delete [] buf;
+        return -1;
     }
 
     delete [] buf;
-    return true;
+    return 1;
 }
 
 unsigned int ThreadExecutor::check()
@@ -134,21 +140,12 @@ unsigned int ThreadExecutor::check()
     }
 
     unsigned int childCount = 0;
-    for (unsigned int i = 0; i < _filenames.size(); i++)
+    unsigned int i = 0;
+    while( true )
     {
-        // Keep only wanted amount of child processes running at a time.
-        if (childCount >= _settings._jobs)
+        // Start a new child
+        if( i < _filenames.size() && childCount < _settings._jobs )
         {
-            while (handleRead(result))
-            {
-
-            }
-
-            int stat = 0;
-            waitpid(0, &stat, 0);
-            --childCount;
-        }
-
             pid_t pid = fork();
             if (pid < 0)
             {
@@ -180,19 +177,31 @@ unsigned int ThreadExecutor::check()
             }
 
             ++childCount;
+            ++i;
+        }
+        else if (childCount > 0)
+        {
+            // Wait for child to quit before stating new processes
+            while(true)
+            {
+                int readRes = handleRead(result);
+                if( readRes == -1 )
+                    break;
+                else if( readRes == 0 )
+                    usleep(5000); // 5 ms
             }
 
-    while (childCount > 0)
-    {
             int stat = 0;
             waitpid(0, &stat, 0);
             --childCount;
         }
-
-    while (handleRead(result))
+        else if(childCount == 0)
         {
-
+            // All done
+            break;
         }
+    }
+
 
     return result;
 }

cli/threadexecutor.h

@@ -58,7 +58,13 @@ private:
 
 #if (defined(__GNUC__) || defined(__sun)) && !defined(__MINGW32__)
 private:
-    bool handleRead(unsigned int &result);
+    /**
+     * Read from the pipe, parse and handle what ever is in there.
+     *@return -1 in case of error
+     *         0 if there is nothing in the pipe to be read
+     *         1 if we did read something
+     */
+    int handleRead(unsigned int &result);
     void writeToPipe(char type, const std::string &data);
     int _pipe[2];
     std::list<std::string> _errorList;

test/testthreadexecutor.cpp

@@ -74,8 +74,7 @@ private:
 
     void run()
     {
-        // This is commented out, because it causes a deadlock
-        // TEST_CASE(deadlock_with_many_errors);
+        TEST_CASE(deadlock_with_many_errors);
         TEST_CASE(no_errors_more_files);
         TEST_CASE(no_errors_less_files);
         TEST_CASE(no_errors_equal_amount_files);