chore: update a few missed functions for 2.3

Signed-off-by: Keith Zantow <kzantow@gmail.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/spdxlib/described_elements.go b/spdxlib/described_elements.go
index 61833b4..a2a6356 100644
--- a/spdxlib/described_elements.go
+++ b/spdxlib/described_elements.go
@@ -9,6 +9,7 @@ import (
 	"github.com/spdx/tools-golang/spdx/common"
 	"github.com/spdx/tools-golang/spdx/v2_1"
 	"github.com/spdx/tools-golang/spdx/v2_2"
+	"github.com/spdx/tools-golang/spdx/v2_3"
 )
 
 // GetDescribedPackageIDs2_1 returns a slice of ElementIDs for all Packages
@@ -112,3 +113,54 @@ func GetDescribedPackageIDs2_2(doc *v2_2.Document) ([]common.ElementID, error) {
 
 	return eIDs, nil
 }
+
+// GetDescribedPackageIDs2_3 returns a slice of ElementIDs for all Packages
+// in this Document that it "describes," according to SPDX rules:
+// - If the document has only one Package, its ID is returned.
+// - If the document has 2+ Packages, it returns the IDs of those that have
+//   a DESCRIBES (or DESCRIBED_BY) relationship to this DOCUMENT.
+func GetDescribedPackageIDs2_3(doc *v2_3.Document) ([]common.ElementID, error) {
+	// if nil Packages map or zero packages in it, return empty slice
+	if doc.Packages == nil {
+		return nil, fmt.Errorf("Packages map is nil")
+	}
+	if len(doc.Packages) == 0 {
+		return nil, fmt.Errorf("no Packages in Document")
+	}
+	if len(doc.Packages) == 1 {
+		// get first (only) one and return its ID
+		for _, pkg := range doc.Packages {
+			return []common.ElementID{pkg.PackageSPDXIdentifier}, nil
+		}
+	}
+
+	// two or more packages, so we need to go through the relationships,
+	// find DESCRIBES or DESCRIBED_BY for this DOCUMENT, verify they are
+	// valid IDs in this document's packages, and return them
+	if doc.Relationships == nil {
+		return nil, fmt.Errorf("multiple Packages in Document but Relationships slice is nil")
+	}
+
+	eIDs, err := FilterRelationships2_3(doc, func(relationship *v2_3.Relationship) *common.ElementID {
+		refDocument := common.MakeDocElementID("", "DOCUMENT")
+
+		if relationship.Relationship == "DESCRIBES" && relationship.RefA == refDocument {
+			return &relationship.RefB.ElementRefID
+		} else if relationship.Relationship == "DESCRIBED_BY" && relationship.RefB == refDocument {
+			return &relationship.RefA.ElementRefID
+		}
+
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	if len(eIDs) == 0 {
+		return nil, fmt.Errorf("no DESCRIBES or DESCRIBED_BY relationships found for this Document")
+	}
+
+	eIDs = SortElementIDs(eIDs)
+
+	return eIDs, nil
+}