groot/{rcmd,riofs,rmeta}: add support for read std::vector<T,my_alloc…

…<T>>

Fixes #820.

groot/rcmd/dump_test.go

@@ -303,6 +303,10 @@ key[003]: eff;1 "efficiency" (TEfficiency) => ignoring key of type *rhist.Effici
 			name: "../testdata/pod-advanced.root",
 			want: loadRef("testdata/pod-advanced.root.txt"),
 		},
+		{
+			name: "../testdata/uproot/uproot-issue-172.root",
+			want: loadRef("testdata/uproot-issue-172.root.txt"),
+		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			got := new(strings.Builder)

groot/riofs/file.go

@@ -797,13 +797,16 @@ func (f *File) StreamerInfo(name string, version int) (rbytes.StreamerInfo, erro
 	// no streamer for "name" in that file.
 	// try whether "name" isn't actually std::vector<T> and a streamer
 	// for T is in that file.
-	o := reStdVector.FindStringSubmatch(name)
-	if o != nil {
-		si := stdvecSIFrom(name, o[1], f)
-		if si != nil {
-			f.sinfos = append(f.sinfos, si)
-			rdict.StreamerInfos.Add(si)
-			return si, nil
+	if strings.Contains(name, "<") {
+		cxx := rmeta.CxxTemplateFrom(name)
+		switch cxx.Name {
+		case "vector":
+			si := stdvecSIFrom(name, cxx.Args[0], f)
+			if si != nil {
+				f.sinfos = append(f.sinfos, si)
+				rdict.StreamerInfos.Add(si)
+				return si, nil
+			}
 		}
 	}
 

groot/riofs/streamers.go

@@ -6,39 +6,27 @@ package riofs
 
 import (
 	"fmt"
-	"regexp"
-	"strings"
+	"reflect"
 
 	"go-hep.org/x/hep/groot/rbytes"
 	"go-hep.org/x/hep/groot/rdict"
 	"go-hep.org/x/hep/groot/rmeta"
 	"go-hep.org/x/hep/groot/root"
 )
 
-var (
-	reStdVector = regexp.MustCompile("^vector<(.+)>$")
-)
-
 func stdvecSIFrom(name, ename string, ctx rbytes.StreamerInfoContext) rbytes.StreamerInfo {
-	const vers = 1
-	ename = strings.TrimSpace(ename)
 	if etyp, ok := rmeta.CxxBuiltins[ename]; ok {
-		si := rdict.NewStreamerInfo(name, vers, []rbytes.StreamerElement{
-			rdict.NewStreamerSTL(
-				name, rmeta.STLvector, rmeta.GoType2ROOTEnum[etyp],
-			),
-		})
-		return si
+		return rdict.StreamerOf(ctx, reflect.SliceOf(etyp))
 	}
 	esi, err := ctx.StreamerInfo(ename, -1)
 	if esi == nil || err != nil {
 		return nil
 	}
-
-	si := rdict.NewStreamerInfo(name, vers, []rbytes.StreamerElement{
-		rdict.NewStreamerSTL(name, rmeta.STLvector, rmeta.Object),
-	})
-	return si
+	etyp, err := rdict.TypeFromSI(ctx, esi)
+	if err != nil || etyp == nil {
+		return nil
+	}
+	return rdict.StreamerOf(ctx, reflect.SliceOf(etyp))
 }
 
 type streamerInfoStore interface {

groot/rmeta/rmeta_test.go

@@ -77,6 +77,13 @@ func TestCxxTemplate(t *testing.T) {
 				Args: []string{"T", "alloc<T>"},
 			},
 		},
+		{
+			name: "vector<float,ROOT::Detail::VecOps::RAdoptAllocator<float> >",
+			want: rmeta.CxxTemplate{
+				Name: "vector",
+				Args: []string{"float", "ROOT::Detail::VecOps::RAdoptAllocator<float>"},
+			},
+		},
 		{
 			name: "std::vector<std::map<K,V,Cmp>>",
 			want: rmeta.CxxTemplate{