[GitHub] [nifi-minifi-cpp] adamdebreceni commented on a change in pull request #928: MINIFICPP-1394 - Speed up ConsumeWindowsEventLog processor

[GitBox]

adamdebreceni commented on a change in pull request #928:
URL: https://github.com/apache/nifi-minifi-cpp/pull/928#discussion_r509021203



##########
File path: extensions/windows-event-log/ConsumeWindowsEventLog.cpp
##########
@@ -514,30 +515,33 @@ void 
ConsumeWindowsEventLog::substituteXMLPercentageItems(pugi::xml_document& do
 
 bool ConsumeWindowsEventLog::createEventRender(EVT_HANDLE hEvent, EventRender& 
eventRender) {
   logger_->log_trace("Rendering an event");
-  DWORD size = 0;
+  DWORD size = sizeof(WCHAR) * 4096;
+  WCHAR stackBuffer[4096];
+  using Deleter = utils::StackAwareDeleter<WCHAR, utils::FreeDeleter>;
+  std::unique_ptr<WCHAR, Deleter> buf{stackBuffer, Deleter{ stackBuffer }};
+
   DWORD used = 0;
   DWORD propertyCount = 0;
-  EvtRender(NULL, hEvent, EvtRenderEventXml, size, 0, &used, &propertyCount);
-  if (ERROR_INSUFFICIENT_BUFFER != GetLastError()) {
-    LOG_LAST_ERROR(EvtRender);
-    return false;
-  }
-
-  if (used > maxBufferSize_) {
-    logger_->log_error("Dropping event because it couldn't be rendered within 
%" PRIu64 " bytes.", maxBufferSize_);
-    return false;
-  }
-
-  size = used;
-  std::vector<wchar_t> buf(size / 2 + 1);
-  if (!EvtRender(NULL, hEvent, EvtRenderEventXml, size, &buf[0], &used, 
&propertyCount)) {
-    LOG_LAST_ERROR(EvtRender);
-    return false;
+  if (!EvtRender(NULL, hEvent, EvtRenderEventXml, size, buf.get(), &used, 
&propertyCount)) {
+    if (ERROR_INSUFFICIENT_BUFFER != GetLastError()) {
+      LOG_LAST_ERROR(EvtRender);
+      return false;
+    }
+    if (used > maxBufferSize_) {
+      logger_->log_error("Dropping event because it couldn't be rendered 
within %" PRIu64 " bytes.", maxBufferSize_);
+      return false;
+    }
+    size = used;
+    buf.reset((LPWSTR)malloc(size));
+    if (!EvtRender(NULL, hEvent, EvtRenderEventXml, size, buf.get(), &used, 
&propertyCount)) {
+      LOG_LAST_ERROR(EvtRender);
+      return false;
+    }
   }
 
   logger_->log_debug("Event rendered with size %" PRIu32 ". Performing doc 
traversing...", size);

Review comment:
       done

##########
File path: extensions/windows-event-log/wel/WindowsEventLog.cpp
##########
@@ -118,8 +120,10 @@ void WindowsEventLogMetadataImpl::renderMetadata() {
 }
 
 std::string WindowsEventLogMetadataImpl::getEventData(EVT_FORMAT_MESSAGE_FLAGS 
flags) const {
-  LPWSTR string_buffer = NULL;
-  DWORD string_buffer_size = 0;
+  DWORD string_buffer_size = 4096;

Review comment:
       done




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