fix: for memory leak issue #576

src/odbc.cpp

@@ -392,6 +392,7 @@ Column* ODBC::GetColumns(SQLHSTMT hStmt, short* colCount)
 
 void ODBC::FreeColumns(Column* columns, short* colCount)
 {
+  DEBUG_PRINTF("ODBC::GetColumns - Entry\n");
   for(int i = 0; i < *colCount; i++) {
       delete [] columns[i].name;
       delete [] columns[i].type_name;
@@ -400,6 +401,7 @@ void ODBC::FreeColumns(Column* columns, short* colCount)
   delete [] columns;
   columns = NULL;
   *colCount = 0;
+  DEBUG_PRINTF("ODBC::GetColumns - Exit\n");
 }
 
 /*
@@ -590,7 +592,7 @@ Local<Value> ODBC::GetColumnValue( SQLHSTMT hStmt, Column column,
       int newbufflen = bufferLength + terCharLen;
       int secondGetData = 0;
       len = 0;
-      if (!buffer) {
+      if (buffer == NULL) {
         buffer = (uint16_t*)malloc(newbufflen);
         if(buffer == NULL)
         {
@@ -628,7 +630,7 @@ Local<Value> ODBC::GetColumnValue( SQLHSTMT hStmt, Column column,
           else
           {
             memcpy(tmp_out_ptr, (char *) buffer, bufferLength);
-            free((uint8_t *)buffer);
+            free((uint16_t *)buffer);
             buffer = tmp_out_ptr;
             len = 0;
             ret = SQLGetData( hStmt,
@@ -646,6 +648,7 @@ Local<Value> ODBC::GetColumnValue( SQLHSTMT hStmt, Column column,
       }
 
       if((int)len == SQL_NULL_DATA) {
+          FREE(buffer);
           return scope.Escape(Nan::Null());
       }
       // In case of secondGetData, we already have result from first getdata
@@ -661,15 +664,14 @@ Local<Value> ODBC::GetColumnValue( SQLHSTMT hStmt, Column column,
             str = Nan::New((char *) buffer).ToLocalChecked();
             #endif
           }
-          if(tmp_out_ptr) {
-            free(tmp_out_ptr); // tmp_out_ptr is pointing to buffer too.
-            buffer = NULL;
-          }
+          FREE(buffer);
+
           //return scope.Escape(Nan::CopyBuffer((char*)buffer, 39767).ToLocalChecked());
       }
       else 
       {
         DEBUG_PRINTF("ODBC::GetColumnValue - An error has occurred, ret = %i\n", ret);
+        FREE(buffer);
         //an error has occured
         //possible values for ret are SQL_ERROR (-1) and SQL_INVALID_HANDLE (-2)
         //If we have an invalid handle, then stuff is way bad and we should abort

src/odbc.h

@@ -316,3 +316,19 @@ struct query_request {
                 static_cast<v8::PropertyAttribute>(v8::ReadOnly|v8::DontDelete))
 
 #endif
+
+// Macro to fee the memory allocated by GETCPPSTR
+#ifdef UNICODE
+  #define FREE(var)               \
+    if (var != NULL) {            \
+      free((uint16_t *)var);      \
+      var = NULL;                 \
+    }
+#else
+  #define FREE(var)               \
+    if (var != NULL) {            \
+      free((char *)var);          \
+      var = NULL;                 \
+    }
+#endif
+

src/odbc_connection.cpp

@@ -310,9 +310,9 @@ void ODBCConnection::UV_AfterOpen(uv_work_t* req, int status)
 
   delete data->cb;
 
-  free(data->connection);
-  free(data);
-  free(req);
+  FREE(data->connection);
+  FREE(data);
+  FREE(req);
   DEBUG_PRINTF("ODBCConnection::UV_AfterOpen - Exit\n");
 }
 
@@ -434,7 +434,7 @@ NAN_METHOD(ODBCConnection::OpenSync)
     #endif*/
   }
 
-  free(connectionString);
+  FREE(connectionString);
   DEBUG_PRINTF("ODBCConnection::OpenSync - Exit\n");
 
   if (err) {
@@ -677,7 +677,7 @@ NAN_METHOD(ODBCConnection::CreateDbSync)
      }
    }
 
-   free(databaseNameString);
+   FREE(databaseNameString);
    if ( !( info[1]->IsNull() ) ) free(codeSetString);
    if ( !( info[1]->IsNull() ) ) free(modeString);
    DEBUG_PRINTF("ODBCConnection::CreateDbSync - Exit\n");
@@ -769,7 +769,7 @@ NAN_METHOD(ODBCConnection::DropDbSync)
      }
    }
 
-   free(databaseNameString);
+   FREE(databaseNameString);
    DEBUG_PRINTF("ODBCConnection::DropDbSync - Exit\n");
 
    if (err) {
@@ -1168,14 +1168,14 @@ void ODBCConnection::UV_AfterQuery(uv_work_t* req, int status)
       FREE_PARAMS( data->params, data->paramCount ) ;
   }
 
-  free(data->sql);
-  free(data->catalog);
-  free(data->schema);
-  free(data->table);
-  free(data->type);
-  free(data->column);
-  free(data);
-  free(req);
+  FREE(data->sql);
+  FREE(data->catalog);
+  FREE(data->schema);
+  FREE(data->table);
+  FREE(data->type);
+  FREE(data->column);
+  FREE(data);
+  FREE(req);
 
   //scope.Close(Undefined());
   DEBUG_PRINTF("ODBCConnection::UV_AfterQuery - Exit\n");
@@ -1318,7 +1318,7 @@ NAN_METHOD(ODBCConnection::QuerySync)
     FREE_PARAMS( params, paramCount ) ;
   }
 
-  free((char*)sql);
+  FREE(sql);
 
   //check to see if there was an error during execution
   if (ret != SQL_SUCCESS) {
@@ -1458,6 +1458,10 @@ void ODBCConnection::UV_Tables(uv_work_t* req)
 
   // this will be checked later in UV_AfterQuery
   data->result = ret; 
+  FREE(data->catalog);
+  FREE(data->schema);
+  FREE(data->table);
+  FREE(data->type);
   DEBUG_PRINTF("ODBCConnection::UV_Tables - Exit\n");
 }
 
@@ -1546,6 +1550,10 @@ void ODBCConnection::UV_Columns(uv_work_t* req)
 
   // this will be checked later in UV_AfterQuery
   data->result = ret;
+  FREE(data->catalog);
+  FREE(data->schema);
+  FREE(data->table);
+  FREE(data->column);
   DEBUG_PRINTF("ODBCConnection::UV_Columns - Exit\n");
 }
 

src/odbc_result.cpp

@@ -84,9 +84,11 @@ void ODBCResult::Free()
     m_canFreeHandle = 0;
   }
 
-  if (bufferLength > 0) {
+  if (bufferLength != 0) {
     bufferLength = 0;
-    free(buffer);
+  }
+  if (buffer != NULL) {
+    free((uint16_t *)buffer);
     buffer = NULL;
   }
 }
@@ -291,6 +293,7 @@ void ODBCResult::UV_AfterFetch(uv_work_t* work_req, int status)
   }
   else {
     ODBC::FreeColumns(data->objResult->columns, &data->objResult->colCount);
+    FREE(data->objResult->buffer);
 
     Local<Value> info[2];
 
@@ -399,6 +402,7 @@ NAN_METHOD(ODBCResult::FetchSync)
   }
   else {
     ODBC::FreeColumns(objResult->columns, &objResult->colCount);
+    FREE(objResult->buffer);
 
     //if there was an error, pass that as arg[0] otherwise Null
     if (error) {
@@ -593,6 +597,7 @@ void ODBCResult::UV_AfterFetchAll(uv_work_t* work_req, int status)
 
     data->cb->Call(3, info);
     ODBC::FreeColumns(self->columns, &self->colCount);
+    FREE(self->buffer);
     delete data->cb;
     data->rows.Reset();
     data->objError.Reset();
@@ -695,6 +700,7 @@ NAN_METHOD(ODBCResult::FetchAllSync)
     }
   }
   ODBC::FreeColumns(self->columns, &self->colCount);
+  FREE(self->buffer);
 
   //throw the error object if there were errors
   if (errorCount > 0) {

src/odbc_statement.cpp

@@ -93,9 +93,11 @@ void ODBCStatement::Free()
     m_hSTMT = (SQLHSTMT)NULL;
   }
 
-  if (bufferLength > 0) {
-      if(buffer) free(buffer);
+  if(buffer != NULL) {
+      free((uint16_t *)buffer);
       buffer = NULL;
+  }
+  if (bufferLength > 0) {
       bufferLength = 0;
   }
   DEBUG_PRINTF("ODBCStatement::Free - Exit\n");