Make SIOFrameData work properly with dropped collections (#400)

src/SIOFrameData.cc

@@ -19,7 +19,8 @@ std::optional<podio::CollectionReadBuffers> SIOFrameData::getCollectionBuffers(c
     // collection indices start at 1!
     const auto index = std::distance(std::begin(names), nameIt) + 1;
 
-    m_availableBlocks[index] = 1;
+    // Mark this block as consumed
+    m_availableBlocks[index] = 0;
     return {dynamic_cast<podio::SIOBlock*>(m_blocks[index].get())->getBuffers()};
   }
 
@@ -35,9 +36,13 @@ std::unique_ptr<podio::GenericParameters> SIOFrameData::getParameters() {
 std::vector<std::string> SIOFrameData::getAvailableCollections() {
   unpackBuffers();
   std::vector<std::string> collections;
-  for (size_t i = 0; i < m_blocks.size(); ++i) {
+  for (size_t i = 1; i < m_blocks.size(); ++i) {
     if (m_availableBlocks[i]) {
-      collections.push_back(m_idTable.name(i));
+      // We have to get the collID of this collection in the idTable as there is
+      // no guarantee that it coincides with the index in the blocks.
+      // Additionally, collection indices start at 1
+      const auto collID = m_idTable.ids()[i - 1];
+      collections.push_back(m_idTable.name(collID));
     }
   }
 

tests/read_frame.cpp

@@ -1,7 +1,9 @@
-#include "podio/ROOTFrameReader.h"
-
 #include "read_frame.h"
+#include "read_frame_auxiliary.h"
+
+#include "podio/ROOTFrameReader.h"
 
 int main() {
-  return read_frames<podio::ROOTFrameReader>("example_frame.root");
+  return read_frames<podio::ROOTFrameReader>("example_frame.root") +
+      test_frame_aux_info<podio::ROOTFrameReader>("example_frame.root");
 }

tests/read_frame_auxiliary.h

@@ -0,0 +1,65 @@
+#ifndef PODIO_TESTS_READ_FRAME_AUXILIARY_H // NOLINT(llvm-header-guard): folder structure not suitable
+#define PODIO_TESTS_READ_FRAME_AUXILIARY_H // NOLINT(llvm-header-guard): folder structure not suitable
+
+#include "write_frame.h"
+
+#include "podio/Frame.h"
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+bool present(const std::string& elem, const std::vector<std::string>& vec) {
+  return std::find(vec.begin(), vec.end(), elem) != vec.end();
+}
+
+int testGetAvailableCollections(const podio::Frame& frame, const std::vector<std::string>& expected) {
+  const auto& collNames = frame.getAvailableCollections();
+  int result = 0;
+  for (const auto& name : expected) {
+    if (!present(name, collNames)) {
+      std::cerr << "Cannot find expected collection " << name << " in collections of Frame" << std::endl;
+      result = 1;
+    }
+  }
+
+  // Get a few collections and make sure that the resutls are unchanged (apart
+  // from ordering)
+  frame.get("hitRefs");
+  frame.get("mcparticles");
+
+  const auto& newCollNames = frame.getAvailableCollections();
+  for (const auto& name : newCollNames) {
+    if (!present(name, collNames)) {
+      std::cerr << "getAvailableCollections returns different collections after getting collections" << std::endl;
+      return 1;
+    }
+  }
+
+  return result;
+}
+
+/**
+ * Test function for testing some auxiliary functionality of the Frame.
+ * Encapsulates everything, such that a corresponding main function boils down
+ * to including the reader to test and defining a main that invokes and returns
+ * this function.
+ *
+ * @param fileName the name of the file to read from
+ * @tparam ReaderT a Frame based I/O capable reader
+ * @return 0 if all checks pass, non-zero otherwise
+ * */
+template <typename ReaderT>
+int test_frame_aux_info(const std::string& fileName) {
+  auto reader = ReaderT{};
+  reader.openFile(fileName);
+
+  // Test on the first event only here. Additionally, also only testing the
+  // "events" category, since that is the one where not all collections are
+  // written
+  auto event = podio::Frame(reader.readEntry("events", 0));
+
+  return testGetAvailableCollections(event, collsToWrite);
+}
+
+#endif // PODIO_TESTS_READ_FRAME_AUXILIARY_H

tests/read_frame_sio.cpp

@@ -1,7 +1,9 @@
-#include "podio/SIOFrameReader.h"
-
 #include "read_frame.h"
+#include "read_frame_auxiliary.h"
+
+#include "podio/SIOFrameReader.h"
 
 int main() {
-  return read_frames<podio::SIOFrameReader>("example_frame.sio");
+  return read_frames<podio::SIOFrameReader>("example_frame.sio") +
+      test_frame_aux_info<podio::SIOFrameReader>("example_frame.sio");
 }