internal/rosa: represent runtime dependencies

This also resolves indirect dependencies, reducing noise.

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

internal/rosa/all.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"net/http"
 	"strconv"
 	"sync"
@@ -167,6 +168,36 @@ const (
 	PresetEnd
 )
 
+// P represents multiple [PArtifact] and is stable through JSON.
+type P []PArtifact
+
+// MarshalJSON represents [PArtifact] by their [Metadata.Name].
+func (s P) MarshalJSON() ([]byte, error) {
+	names := make([]string, len(s))
+	for i, p := range s {
+		names[i] = GetMetadata(p).Name
+	}
+	return json.Marshal(names)
+}
+
+// UnmarshalJSON resolves the value created by MarshalJSON back to [P].
+func (s *P) UnmarshalJSON(data []byte) error {
+	var names []string
+	if err := json.Unmarshal(data, &names); err != nil {
+		return err
+	}
+
+	*s = make(P, len(names))
+	for i, name := range names {
+		if p, ok := ResolveName(name); !ok {
+			return fmt.Errorf("unknown artifact %q", name)
+		} else {
+			(*s)[i] = p
+		}
+	}
+	return nil
+}
+
 // Metadata is stage-agnostic information of a [PArtifact] not directly
 // representable in the resulting [pkg.Artifact].
 type Metadata struct {
@@ -179,6 +210,9 @@ type Metadata struct {
 	// Project home page.
 	Website string `json:"website,omitempty"`
 
+	// Runtime dependencies.
+	Dependencies P `json:"dependencies"`
+
 	// Project identifier on [Anitya].
 	//
 	// [Anitya]: https://release-monitoring.org/

internal/rosa/rosa.go

@@ -8,6 +8,7 @@ import (
 	"slices"
 	"strconv"
 	"strings"
+	"sync"
 
 	"hakurei.app/container/fhs"
 	"hakurei.app/internal/pkg"
@@ -454,6 +455,48 @@ type PackageAttr struct {
 	Flag int
 }
 
+// pa holds whether a [PArtifact] is present.
+type pa = [PresetEnd]bool
+
+// paPool holds addresses of pa.
+var paPool = sync.Pool{New: func() any { return new(pa) }}
+
+// paGet returns the address of a new pa.
+func paGet() *pa { return paPool.Get().(*pa) }
+
+// paPut returns a pa to paPool.
+func paPut(pv *pa) { *pv = pa{}; paPool.Put(pv) }
+
+// appendPreset recursively appends a [PArtifact] and its runtime dependencies.
+func (t Toolchain) appendPreset(
+	a []pkg.Artifact,
+	pv *pa, p PArtifact,
+) []pkg.Artifact {
+	if pv[p] {
+		return a
+	}
+	pv[p] = true
+
+	for _, d := range GetMetadata(p).Dependencies {
+		a = t.appendPreset(a, pv, d)
+	}
+	return append(a, t.Load(p))
+}
+
+// AppendPresets recursively appends multiple [PArtifact] and their runtime
+// dependencies.
+func (t Toolchain) AppendPresets(
+	a []pkg.Artifact,
+	presets ...PArtifact,
+) []pkg.Artifact {
+	pv := paGet()
+	for _, p := range presets {
+		a = t.appendPreset(a, pv, p)
+	}
+	paPut(pv)
+	return a
+}
+
 // NewPackage constructs a [pkg.Artifact] via a build system helper.
 func (t Toolchain) NewPackage(
 	name, version string,
@@ -486,12 +529,14 @@ func (t Toolchain) NewPackage(
 	extraRes := make([]pkg.Artifact, 0, dc)
 	extraRes = append(extraRes, attr.NonStage0...)
 	if !t.isStage0() {
+		pv := paGet()
 		for _, p := range helper.extra(attr.Flag) {
-			extraRes = append(extraRes, t.Load(p))
+			extraRes = t.appendPreset(extraRes, pv, p)
 		}
 		for _, p := range extra {
-			extraRes = append(extraRes, t.Load(p))
+			extraRes = t.appendPreset(extraRes, pv, p)
 		}
+		paPut(pv)
 	}
 
 	var scriptEarly string