internal/rosa: expose supported architectures

This information is useful to external tooling and makes a lot more sense in this package than cmd/mbf. This change also fixes non-native artifact resolution during clean.

Signed-off-by: Ophestra <cat@gensokyo.uk>

2 files changed, 47 insertions, 3 deletions

diff --git a/internal/rosa/rosa.go b/internal/rosa/rosa.go
index 0a61e9ec..a5972e35 100644
--- a/internal/rosa/rosa.go
+++ b/internal/rosa/rosa.go
@@ -443,12 +443,11 @@ func (t Toolchain) appendHandle(a []pkg.Artifact, pv pa, p ArtifactH) []pkg.Arti
 	}
 	pv[p] = struct{}{}
 
-	meta, _ := t.MustLoad(p)
+	meta, u := t.MustLoad(p)
 	for _, d := range meta.Dependencies {
 		a = t.appendHandle(a, pv, d)
 	}
-	_, d := t.MustLoad(p)
-	return append(a, d)
+	return append(a, u)
 }
 
 // Append recursively appends multiple [Artifact] named by their handles, and
diff --git a/internal/rosa/state.go b/internal/rosa/state.go
index 6f2c05cb..864b70fa 100644
--- a/internal/rosa/state.go
+++ b/internal/rosa/state.go
@@ -9,6 +9,7 @@ import (
 	"errors"
 	"io"
 	"io/fs"
+	"iter"
 	"net/http"
 	"path/filepath"
 	"reflect"
@@ -22,6 +23,7 @@ import (
 	"unsafe"
 
 	"hakurei.app/check"
+	"hakurei.app/container"
 	"hakurei.app/internal/pkg"
 	"hakurei.app/internal/rosa/azalea"
 )
@@ -239,6 +241,49 @@ func (s *S) wantsArch() {
 // Arch returns the target architecture.
 func (s *S) Arch() string { s.wantsArch(); return s.arch }
 
+// Arches returns an iterator over supported emulation targets.
+func Arches(qemu *check.Absolute) iter.Seq2[string, container.BinfmtEntry] {
+	return func(yield func(string, container.BinfmtEntry) bool) {
+		for _, target := range []struct {
+			arch, name  string
+			offset      byte
+			magic, mask string
+		}{{
+			arch:   "riscv64",
+			offset: 0,
+			magic:  "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xf3\x00",
+			mask:   "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff",
+		}, {
+			arch:   "arm64",
+			name:   "aarch64",
+			offset: 0,
+			magic:  "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00",
+			mask:   "\xff\xff\xff\xff\xff\xff\xff\xfc\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff",
+		}} {
+			name := target.name
+			if name == "" {
+				name = target.arch
+			}
+			var interpreter *check.Absolute
+			if qemu != nil {
+				interpreter = qemu.Append(
+					"system/bin",
+					"qemu-"+name,
+				)
+			}
+
+			if !yield(target.arch, container.BinfmtEntry{
+				Offset:      target.offset,
+				Magic:       target.magic,
+				Mask:        target.mask,
+				Interpreter: interpreter,
+			}) {
+				return
+			}
+		}
+	}
+}
+
 // Flags returns the current preset flags.
 func (s *S) Flags() int { return s.opts }