[ntuple] Remove use of RNTupleReader

tree/ntupleutil/v7/inc/ROOT/RNTupleInspector.hxx

@@ -54,14 +54,14 @@ std::cout << "The compression factor is " << std::fixed << std::setprecision(2)
 // clang-format on
 class RNTupleInspector {
 private:
-   RNTupleInspector() = default;
-
-   const RNTupleDescriptor *fSourceNTupleDescriptor;
+   std::shared_ptr<ROOT::Experimental::Detail::RPageSource> fPageSource;
    int fCompressionSettings;
    std::uint64_t fCompressedSize;
    std::uint64_t fUncompressedSize;
    float fCompressionFactor;
 
+   RNTupleInspector(std::shared_ptr<ROOT::Experimental::Detail::RPageSource> pageSource) : fPageSource(pageSource) {};
+
    void CollectSizeData();
 
 public:
@@ -72,7 +72,7 @@ public:
    ~RNTupleInspector() = default;
 
    /// Creates a new inspector for a given RNTuple.
-   static RResult<std::unique_ptr<RNTupleInspector>> Create(std::unique_ptr<RNTupleReader> &sourceNTupleReader);
+   static RResult<std::unique_ptr<RNTupleInspector>> Create(std::shared_ptr<ROOT::Experimental::Detail::RPageSource> pageSource);
    static RResult<std::unique_ptr<RNTupleInspector>> Create(RNTuple *sourceNTuple);
 
    /// Get the name of the RNTuple being inspected.

tree/ntupleutil/v7/src/RNTupleInspector.cxx

@@ -23,11 +23,13 @@
 
 void ROOT::Experimental::RNTupleInspector::CollectSizeData()
 {
+   fPageSource->Attach();
+   auto descriptorGuard = fPageSource->GetSharedDescriptorGuard();
    int compressionSettings = -1;
    std::uint64_t compressedSize = 0;
    std::uint64_t uncompressedSize = 0;
 
-   for (const auto &clusterDescriptor : fSourceNTupleDescriptor->GetClusterIterable()) {
+   for (const auto &clusterDescriptor : descriptorGuard->GetClusterIterable()) {
       compressedSize += clusterDescriptor.GetBytesOnStorage();
 
       if (compressionSettings == -1) {
@@ -35,13 +37,13 @@ void ROOT::Experimental::RNTupleInspector::CollectSizeData()
       }
    }
 
-   for (uint64_t colId = 0; colId < fSourceNTupleDescriptor->GetNColumns(); ++colId) {
-      const ROOT::Experimental::RColumnDescriptor &colDescriptor = fSourceNTupleDescriptor->GetColumnDescriptor(colId);
+   for (uint64_t colId = 0; colId < descriptorGuard->GetNColumns(); ++colId) {
+      const ROOT::Experimental::RColumnDescriptor &colDescriptor = descriptorGuard->GetColumnDescriptor(colId);
 
       uint64_t elemSize =
          ROOT::Experimental::Detail::RColumnElementBase::Generate(colDescriptor.GetModel().GetType())->GetSize();
 
-      uint64_t nElems = fSourceNTupleDescriptor->GetNElements(colId);
+      uint64_t nElems = descriptorGuard->GetNElements(colId);
       uncompressedSize += nElems * elemSize;
    }
 
@@ -51,35 +53,28 @@ void ROOT::Experimental::RNTupleInspector::CollectSizeData()
 }
 
 ROOT::Experimental::RResult<std::unique_ptr<ROOT::Experimental::RNTupleInspector>>
-ROOT::Experimental::RNTupleInspector::Create(std::unique_ptr<RNTupleReader> &sourceNTupleReader)
+ROOT::Experimental::RNTupleInspector::Create(std::shared_ptr<ROOT::Experimental::Detail::RPageSource> pageSource)
 {
-   auto inspector = std::unique_ptr<RNTupleInspector>(new RNTupleInspector());
-
-   inspector->fSourceNTupleDescriptor = sourceNTupleReader->GetDescriptor();
-
-   if (!inspector->fSourceNTupleDescriptor) {
-      return R__FAIL("cannot get descriptor for provided RNTuple");
-   }
+   auto inspector = std::unique_ptr<RNTupleInspector>(new RNTupleInspector(pageSource));
 
    inspector->CollectSizeData();
+
    return inspector;
 }
 
 ROOT::Experimental::RResult<std::unique_ptr<ROOT::Experimental::RNTupleInspector>>
 ROOT::Experimental::RNTupleInspector::Create(ROOT::Experimental::RNTuple *sourceNTuple)
 {
-   auto reader = ROOT::Experimental::RNTupleReader::Open(sourceNTuple);
-
-   if (!reader) {
-      return R__FAIL("cannot get reader for provided RNTuple");
-   }
+   std::shared_ptr<ROOT::Experimental::Detail::RPageSource> pageSource = sourceNTuple->MakePageSource();
 
-   return ROOT::Experimental::RNTupleInspector::Create(reader);
+   return ROOT::Experimental::RNTupleInspector::Create(pageSource);
 }
 
 std::string ROOT::Experimental::RNTupleInspector::GetName()
 {
-   return fSourceNTupleDescriptor->GetName();
+   fPageSource->Attach();
+   auto descriptorGuard = fPageSource->GetSharedDescriptorGuard();
+   return descriptorGuard->GetName();
 }
 
 int ROOT::Experimental::RNTupleInspector::GetCompressionSettings()

tree/ntupleutil/v7/test/ntuple_inspector.cxx

@@ -2,16 +2,15 @@
 #include <ROOT/RNTupleOptions.hxx>
 
 #include <TFile.h>
-#include <TTree.h>
 
-#include <cstdio>
-#include <string>
-#include <tuple>
-#include <utility>
-#include <vector>
+// #include <cstdio>
+// #include <string>
+// #include <tuple>
+// #include <utility>
 
 #include "ntupleutil_test.hxx"
 
+using ROOT::Experimental::RNTuple;
 using ROOT::Experimental::RNTupleInspector;
 using ROOT::Experimental::RNTupleModel;
 using ROOT::Experimental::RNTupleReader;
@@ -26,8 +25,10 @@ TEST(RNTupleInspector, Name)
       RNTupleWriter::Recreate(std::move(model), "ntuple", fileGuard.GetPath());
    }
 
-   auto ntuple = RNTupleReader::Open("ntuple", fileGuard.GetPath());
+   std::unique_ptr<TFile> file(TFile::Open(fileGuard.GetPath().c_str()));
+   auto ntuple = file->Get<RNTuple>("ntuple");
    auto inspector = RNTupleInspector::Create(ntuple).Unwrap();
+
    EXPECT_EQ("ntuple", inspector->GetName());
 }
 
@@ -46,9 +47,10 @@ TEST(RNTupleInspector, CompressionSettings)
       ntuple->Fill();
    }
 
-   auto ntuple = RNTupleReader::Open("ntuple", fileGuard.GetPath());
-
+   std::unique_ptr<TFile> file(TFile::Open(fileGuard.GetPath().c_str()));
+   auto ntuple = file->Get<RNTuple>("ntuple");
    auto inspector = RNTupleInspector::Create(ntuple).Unwrap();
+
    EXPECT_EQ(505, inspector->GetCompressionSettings());
 }
 
@@ -67,9 +69,10 @@ TEST(RNTupleInspector, SizeUncompressed)
       ntuple->Fill();
    }
 
-   auto ntuple = RNTupleReader::Open("ntuple", fileGuard.GetPath());
-
+   std::unique_ptr<TFile> file(TFile::Open(fileGuard.GetPath().c_str()));
+   auto ntuple = file->Get<RNTuple>("ntuple");
    auto inspector = RNTupleInspector::Create(ntuple).Unwrap();
+
    EXPECT_EQ(sizeof(int32_t), inspector->GetUncompressedSize());
    EXPECT_EQ(inspector->GetCompressedSize(), inspector->GetUncompressedSize());
 }
@@ -91,9 +94,10 @@ TEST(RNTupleInspector, SizeCompressed)
       }
    }
 
-   auto ntuple = RNTupleReader::Open("ntuple", fileGuard.GetPath());
-
+   std::unique_ptr<TFile> file(TFile::Open(fileGuard.GetPath().c_str()));
+   auto ntuple = file->Get<RNTuple>("ntuple");
    auto inspector = RNTupleInspector::Create(ntuple).Unwrap();
+
    EXPECT_NE(inspector->GetCompressedSize(), inspector->GetUncompressedSize());
 }
 
@@ -105,9 +109,10 @@ TEST(RNTupleInspector, SizeEmpty)
       RNTupleWriter::Recreate(std::move(model), "ntuple", fileGuard.GetPath());
    }
 
-   auto ntuple = RNTupleReader::Open("ntuple", fileGuard.GetPath());
-
+   std::unique_ptr<TFile> file(TFile::Open(fileGuard.GetPath().c_str()));
+   auto ntuple = file->Get<RNTuple>("ntuple");
    auto inspector = RNTupleInspector::Create(ntuple).Unwrap();
+
    EXPECT_EQ(0, inspector->GetCompressedSize());
    EXPECT_EQ(0, inspector->GetUncompressedSize());
 }
@@ -129,9 +134,10 @@ TEST(RNTupleInspector, SingleIntFieldCompression)
       }
    }
 
-   auto ntuple = RNTupleReader::Open("ntuple", fileGuard.GetPath());
-
+   std::unique_ptr<TFile> file(TFile::Open(fileGuard.GetPath().c_str()));
+   auto ntuple = file->Get<RNTuple>("ntuple");
    auto inspector = RNTupleInspector::Create(ntuple).Unwrap();
+
    EXPECT_LT(0, inspector->GetCompressedSize());
    EXPECT_LT(inspector->GetCompressedSize(), inspector->GetUncompressedSize());
    EXPECT_GT(inspector->GetCompressionFactor(), 1);