From 9a12043b5085deab1eb47f65d3d92324b2f99403 Mon Sep 17 00:00:00 2001
From: Tamas Gal <himself@tamasgal.com>
Date: Fri, 31 Mar 2023 12:08:50 +0200
Subject: [PATCH] Custom TObject hook (#232)

* Preliminary debugging for generic tobject stuff

* Add parser logic

* Add tests

* Bump version number
---
 Project.toml     |  2 +-
 src/bootstrap.jl | 27 +++++++++++++++++++++++++++
 src/root.jl      | 15 +++++++++++----
 test/runtests.jl | 11 +++++++++++
 4 files changed, 50 insertions(+), 5 deletions(-)

diff --git a/Project.toml b/Project.toml
index eb51ffde..65d3ad87 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "UnROOT"
 uuid = "3cd96dde-e98d-4713-81e9-a4a1b0235ce9"
 authors = ["Tamas Gal", "Jerry Ling", "Johannes Schumann", "Nick Amin"]
-version = "0.10.1"
+version = "0.10.2"
 
 [deps]
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"
diff --git a/src/bootstrap.jl b/src/bootstrap.jl
index 70074cf6..efae5b95 100644
--- a/src/bootstrap.jl
+++ b/src/bootstrap.jl
@@ -885,6 +885,33 @@ function TNtuple(io, tkey::TKey, refs)
     tree = TTree(io, tkey, refs; top=false) #embeded tree
 end
 
+"""
+Direct parsing of streamed objects which are not sitting on branches.
+"""
+function parsetobject(io, tkey::TKey, streamer)
+    # pass the correct parser from f!
+    io = datastream(io, tkey)
+    preamble = Preamble(io, Missing)
+
+    @initparse
+
+    # the first entry in the streamer is a TOBject
+    parsefields!(io, fields, TObject)
+
+    # the second (and last) entry is the actual data streamer (we think)
+    s = streamer.streamer.fElements.elements[2]
+    if s.fTypeName == "map<string,string>"
+        skip(io, 3*4)  # unclear what the first 12 bytes are
+        # this gives the number of elements
+        n = readtype(io, Int32)
+        skip(io, 6)  # the usual header stuff?
+        keys = [readtype(io, String) for i ∈ 1:n]
+        skip(io, 6)  # the usual header stuff?
+        values = [readtype(io, String) for i ∈ 1:n]
+        return Dict(zip(keys, values))
+    end
+    error("Unable to parse '$(s.fTypeName)' of '$(tkey.fClassName)'")
+end
 
 # FIXME preliminary TTree implementation
 function TTree(io, tkey::TKey, refs; top=true)
diff --git a/src/root.jl b/src/root.jl
index 7ca3fdd9..3e4925a2 100644
--- a/src/root.jl
+++ b/src/root.jl
@@ -162,10 +162,17 @@ end
         return f[first(paths)][join(paths[2:end], "/")]
     end
     tkey = f.directory.keys[findfirst(isequal(s), keys(f))]
-    @debug "Retrieving $s ('$(tkey.fClassName)')"
-    streamer = getfield(@__MODULE__, Symbol(safename(tkey.fClassName)))
-    S = streamer(f.fobj, tkey, f.streamers.refs)
-    return S
+    typename = safename(tkey.fClassName)
+    @debug "Retrieving $s ('$(typename)')"
+    try
+        streamer = getfield(@__MODULE__, Symbol(typename))
+        S = streamer(f.fobj, tkey, f.streamers.refs)
+        return S
+    catch UndefVarError
+    end
+
+    # last resort, try direct parsing
+    parsetobject(f.fobj, tkey, streamerfor(f, typename))
 end
 
 # FIXME unify with above?
diff --git a/test/runtests.jl b/test/runtests.jl
index 78d971f3..d542d106 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -218,6 +218,17 @@ end
     # close(rootfile)
 end
 
+@testset "Single TObject subclasses" begin
+    f = UnROOT.samplefile("triply_jagged_via_custom_class.root")
+    # map<string,string>
+    head = f["Head"]
+    @test 27 == length(f["Head"])
+    @test " 3.3" == head["DAQ"]
+    @test " CORSIKA 7.640 181111 1211" == head["physics"]
+    @test "MUSIC seawater 02-03  190204  1643" == head["propag"]
+    close(f)
+end
+
 @testset "LazyBranch and LazyTree" begin
     rootfile = ROOTFile(joinpath(SAMPLES_DIR, "tree_with_large_array.root"))
     branch = rootfile["t1"]["int32_array"]