make rntviewer more resilient to corrupted files

src/hover.cpp

@@ -719,13 +719,12 @@ Sec_Hover_Info get_section_hover_info(Arena *arena, Section section, u64 off, co
           // so they're always occupying only 8 bytes.
           || hover.field_le<u64>("Flags: 0x%" PRIX64)
           || hover.field_le<u64>("Header checksum: 0x%" PRIX64)
+          || hover.frame_header()
           || hover.schema_description("Schema Extension")
-          // TODO:
+          //  - list of column group record frames (TODO)
-          //  - list of column group record frames
+          || hover.frame_header("Column Groups")
-          || hover.frame_header()
+          //  - list of cluster group record frames (TODO)
-          //  - list of cluster group record frames
+          || hover.frame_header("Cluster Groups")
-          || hover.frame_header()
-          || hover.cluster_group()
           || hover.range("Payload", section.range.len - hover.cur_field_off)
           || hover.field_le<u64>("Checksum: 0x%" PRIX64)
           ;

src/rntuple.cpp

@@ -34,8 +34,12 @@ ROOT::Experimental::RNTupleDescriptor create_descriptor(Arena *arena, RMicroFile
   
   // Deserialize header+footer
   RNTupleDescriptorBuilder desc_builder;
+  try {
     RNTupleSerializer::DeserializeHeader(header, anchor.fLenHeader, desc_builder);
     RNTupleSerializer::DeserializeFooter(footer, anchor.fLenFooter, desc_builder);
+  } catch (...) {
+    fprintf(stderr, "Failed to deserialize header/footer!\n");
+  }
 
   RNTupleDescriptor descriptor = desc_builder.MoveDescriptor();
   for (const RClusterGroupDescriptor &cgdesc : descriptor.GetClusterGroupIterable()) {
@@ -262,19 +266,26 @@ void gather_ntuple_metadata(Arena *arena, RMicroFileReader &reader, const RNTupl
   // that an offset belongs to.
   // A page chunk is a grouping of adjacent pages, used to quickly determine if an offset is part
   // of a page or not.
-  assert(pinfo_head);
+  Page_Info_Group *groups = nullptr;
+  Page_Info_Chunk *chunks_head = nullptr, *chunks_tail = nullptr;
+  u64 n_groups = 0;
+  u64 n_chunks = 0;
+  u64 idx = 0;
+  // NOTE: pinfo_head may be null if we failed to load any page (which may happen e.g. if the rntuple
+  // is corrupted)
+  if (pinfo_head) {
     const u64 GROUP_SIZE = 500;
-  Page_Info_Group *groups = arena_push_array_nozero<Page_Info_Group>(arena, n_pages / GROUP_SIZE + 1);
+    groups = arena_push_array_nozero<Page_Info_Group>(arena, n_pages / GROUP_SIZE + 1);
-  u64 n_groups = 1;
+    n_groups = 1;
     groups->first = pinfo_head;
     groups->range.start = pinfo_head->range.start;
 
-  Page_Info_Chunk *chunks_head = arena_push<Page_Info_Chunk>(arena);
+    chunks_head = arena_push<Page_Info_Chunk>(arena);
-  Page_Info_Chunk *chunks_tail = chunks_head;
+    chunks_tail = chunks_head;
     chunks_head->range = pinfo_head->range;
-  u64 n_chunks = 1;
+    n_chunks = 1;
 
-  u64 idx = 1;
+    idx = 1;
     [[maybe_unused]] Page_Info_Node *prev = pinfo_head;
     for (Page_Info_Node *pinfo = pinfo_head->next; pinfo; pinfo = pinfo->next) {
       assert(prev->range.end() <= pinfo->range.start);
@@ -310,17 +321,20 @@ void gather_ntuple_metadata(Arena *arena, RMicroFileReader &reader, const RNTupl
 
       ++n_groups;
     }
+  }
 
   // verify that we added all pages to chunks
   assert(idx == n_pages);
 
+  if (n_groups) {
     Page_Info_Group &last_group = groups[n_groups - 1];
     last_group.range.len = pinfo_tail->range.end() - last_group.range.start;
+  }
 
   fprintf(stderr, "Generated %" PRIu64 " groups and %" PRIu64 " chunks.\n", n_groups, n_chunks);
 
-  assert(!chunks_tail->next);
+  assert(!chunks_tail || !chunks_tail->next);
-  assert(!pinfo_tail->next);
+  assert(!pinfo_tail || !pinfo_tail->next);
 
   rndata.pages = pinfo_head;
   rndata.page_groups = groups;