Refactor parser to handle element ID maps

Signed-off-by: Steve Winslow <steve@swinslow.net>

1 files changed, 75 insertions, 0 deletions

diff --git a/tvloader/parser2v1/util.go b/tvloader/parser2v1/util.go
index ed99063..d2df57b 100644
--- a/tvloader/parser2v1/util.go
+++ b/tvloader/parser2v1/util.go
@@ -5,6 +5,8 @@ package parser2v1
 import (
 	"fmt"
 	"strings"
+
+	"github.com/spdx/tools-golang/spdx"
 )
 
 // used to extract key / value from embedded substrings
@@ -21,3 +23,76 @@ func extractSubs(value string) (string, string, error) {
 
 	return subkey, subvalue, nil
 }
+
+// used to extract DocumentRef and SPDXRef values from an SPDX Identifier
+// which can point either to this document or to a different one
+func extractDocElementID(value string) (spdx.DocElementID, error) {
+	docRefID := ""
+	idStr := value
+
+	// check prefix to see if it's a DocumentRef ID
+	if strings.HasPrefix(idStr, "DocumentRef-") {
+		// extract the part that comes between "DocumentRef-" and ":"
+		strs := strings.Split(idStr, ":")
+		// should be exactly two, part before and part after
+		if len(strs) < 2 {
+			return spdx.DocElementID{}, fmt.Errorf("no colon found although DocumentRef- prefix present")
+		}
+		if len(strs) > 2 {
+			return spdx.DocElementID{}, fmt.Errorf("more than one colon found")
+		}
+
+		// trim the prefix and confirm non-empty
+		docRefID = strings.TrimPrefix(strs[0], "DocumentRef-")
+		if docRefID == "" {
+			return spdx.DocElementID{}, fmt.Errorf("document identifier has nothing after prefix")
+		}
+		// and use remainder for element ID parsing
+		idStr = strs[1]
+	}
+
+	// check prefix to confirm it's got the right prefix for element IDs
+	if !strings.HasPrefix(idStr, "SPDXRef-") {
+		return spdx.DocElementID{}, fmt.Errorf("missing SPDXRef- prefix for element identifier")
+	}
+
+	// make sure no colons are present
+	if strings.Contains(idStr, ":") {
+		// we know this means there was no DocumentRef- prefix, because
+		// we would have handled multiple colons above if it was
+		return spdx.DocElementID{}, fmt.Errorf("invalid colon in element identifier")
+	}
+
+	// trim the prefix and confirm non-empty
+	eltRefID := strings.TrimPrefix(idStr, "SPDXRef-")
+	if eltRefID == "" {
+		return spdx.DocElementID{}, fmt.Errorf("element identifier has nothing after prefix")
+	}
+
+	// we're good
+	return spdx.DocElementID{DocumentRefID: docRefID, ElementRefID: spdx.ElementID(eltRefID)}, nil
+}
+
+// used to extract SPDXRef values only from an SPDX Identifier which can point
+// to this document only. Use extractDocElementID for parsing IDs that can
+// refer either to this document or a different one.
+func extractElementID(value string) (spdx.ElementID, error) {
+	// check prefix to confirm it's got the right prefix for element IDs
+	if !strings.HasPrefix(value, "SPDXRef-") {
+		return spdx.ElementID(""), fmt.Errorf("missing SPDXRef- prefix for element identifier")
+	}
+
+	// make sure no colons are present
+	if strings.Contains(value, ":") {
+		return spdx.ElementID(""), fmt.Errorf("invalid colon in element identifier")
+	}
+
+	// trim the prefix and confirm non-empty
+	eltRefID := strings.TrimPrefix(value, "SPDXRef-")
+	if eltRefID == "" {
+		return spdx.ElementID(""), fmt.Errorf("element identifier has nothing after prefix")
+	}
+
+	// we're good
+	return spdx.ElementID(eltRefID), nil
+}