[rfile] Add possibility of setting an object title when writing

Author: silverweed

io/io/inc/ROOT/RFile.hxx

@@ -336,8 +336,8 @@ public:
       void *obj = GetUntyped(path, typeid(T));
       return std::unique_ptr<T>(static_cast<T *>(obj));
    }
-  
-   /// Puts object `obj` into the file.
+
+   /// Puts object `obj` into the file, optionally giving it a title.
    /// The object will be effectively copied into the file, so any further modifications won't be seen by the object
    /// inside the file.
    /// Note that the object is not necessarily written to storage until the RFile is closed or `Flush()` is called.
@@ -348,9 +348,9 @@ public:
    /// \throws ROOT::RException if `path` already identifies a valid object or directory.
    /// \throws ROOT::RException if the file was opened in read-only mode.
    template <typename T>
-   void Put(std::string_view path, const T &obj)
+   void Put(std::string_view path, const T &obj, std::string_view title = "")
    {
-      PutInternal(path, obj, /* flags = */ 0);
+      PutInternal(path, obj, /* flags = */ 0, title);
    }
 
    /// Puts an object into the file, overwriting any previously-existing object at that path.
@@ -365,10 +365,17 @@ public:
    /// \throws ROOT::RException if the file was opened in read-only mode.
    template <typename T>
    void Overwrite(std::string_view path, const T &obj, bool createNewCycle = true)
+   {
+      Overwrite(path, obj, "", createNewCycle);
+   }
+
+   /// Like Overwrite(std::string_view, const T&, bool) but allows giving a title to the object.
+   template <typename T>
+   void Overwrite(std::string_view path, const T &obj, std::string_view title, bool createNewCycle = true)
    {
       std::uint32_t flags = kPutFlag_AllowOverwrite;
       flags |= createNewCycle * kPutFlag_OverwriteKeepCycle;
-      PutInternal(path, obj, flags);
+      PutInternal(path, obj, flags, title);
    }
 
    /// Writes all objects and the file structure to disk.

io/io/test/rfile.cxx

@@ -231,13 +231,15 @@ TEST(RFile, PutOverwrite)
    {
       TH1D hist("hist", "", 100, -10, 10);
       hist.FillRandom("gaus", 1000);
-      file->Put("hist", hist);
+      file->Put("hist", hist, "My Histo");
    }
 
    {
       auto hist = file->Get<TH1D>("hist");
       ASSERT_TRUE(hist);
       EXPECT_EQ(static_cast<int>(hist->GetEntries()), 1000);
+      auto key = file->GetKeyInfo("hist").value();
+      EXPECT_EQ(key.GetTitle(), "My Histo");
    }
 
    // Try putting another object at the same path, should fail
@@ -267,6 +269,8 @@ TEST(RFile, PutOverwrite)
       // ...but any cycle before the latest should still be there!
       hist = file->Get<TH1D>("hist;1");
       EXPECT_NE(hist, nullptr);
+      auto key = file->GetKeyInfo("hist;1").value();
+      EXPECT_EQ(key.GetTitle(), "My Histo");
    }
 }
 

io/io/test/rfile.py

@@ -63,7 +63,7 @@ def test_getkeyinfo(self):
             with RFile.Recreate(fileName) as rfile:
                 hist = ROOT.TH1D("hist", "", 100, -10, 10)
                 hist.FillRandom("gaus", 10)
-                rfile.Put("hist", hist)
+                rfile.Put("hist", hist, "My Histo")
                 rfile.Put("foo/hist", hist)
                 rfile.Put("foo/bar/hist", hist)
                 rfile.Put("foo/bar/hist2", hist)
@@ -73,6 +73,7 @@ def test_getkeyinfo(self):
                 key = rfile.GetKeyInfo("hist")
                 self.assertEqual(key.GetPath(), "hist")
                 self.assertEqual(key.GetClassName(), "TH1D")
+                self.assertEqual(key.GetTitle(), "My Histo")
 
                 key = rfile.GetKeyInfo("does_not_exist")
                 self.assertEqual(key, None)