From 408b615c3c0c478a5b6485155f2fffc57ab452eb Mon Sep 17 00:00:00 2001
From: Aleksa Sarai <asarai@suse.de>
Date: Sat, 12 Nov 2016 15:03:20 +1100
Subject: [PATCH] entries: comment with keyword metadata

Since not every keyword applies to every type entry, include a comment
with the keywords the manifest was generated with.

Signed-off-by: Aleksa Sarai <asarai@suse.de>
Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>
---
 tar.go  |  9 +++++++--
 walk.go | 22 ++++++++++++++++++++--
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/tar.go b/tar.go
index 8165841..8d9e0dd 100644
--- a/tar.go
+++ b/tar.go
@@ -82,8 +82,13 @@ func (ts *tarStream) readHeaders() {
 		Set:      nil,
 		Keywords: []KeyVal{"type=dir"},
 	}
-	metadataEntries := signatureEntries("<user specified tar archive>")
-	for _, e := range metadataEntries {
+	// insert signature and metadata comments first (user, machine, tree, date)
+	for _, e := range signatureEntries("<user specified tar archive>") {
+		e.Pos = len(ts.creator.DH.Entries)
+		ts.creator.DH.Entries = append(ts.creator.DH.Entries, e)
+	}
+	// insert keyword metadata next
+	for _, e := range keywordEntries(ts.keywords) {
 		e.Pos = len(ts.creator.DH.Entries)
 		ts.creator.DH.Entries = append(ts.creator.DH.Entries, e)
 	}
diff --git a/walk.go b/walk.go
index 5209d6e..7f5b171 100644
--- a/walk.go
+++ b/walk.go
@@ -7,6 +7,7 @@ import (
 	"os/user"
 	"path/filepath"
 	"sort"
+	"strings"
 	"time"
 )
 
@@ -28,11 +29,16 @@ var defaultSetKeywords = []KeyVal{"type=file", "nlink=1", "flags=none", "mode=06
 func Walk(root string, excludes []ExcludeFunc, keywords []Keyword) (*DirectoryHierarchy, error) {
 	creator := dhCreator{DH: &DirectoryHierarchy{}}
 	// insert signature and metadata comments first (user, machine, tree, date)
-	metadataEntries := signatureEntries(root)
-	for _, e := range metadataEntries {
+	for _, e := range signatureEntries(root) {
 		e.Pos = len(creator.DH.Entries)
 		creator.DH.Entries = append(creator.DH.Entries, e)
 	}
+	// insert keyword metadata next
+	for _, e := range keywordEntries(keywords) {
+		e.Pos = len(creator.DH.Entries)
+		creator.DH.Entries = append(creator.DH.Entries, e)
+	}
+	// walk the directory and add entries
 	err := startWalk(&creator, root, func(path string, info os.FileInfo, err error) error {
 		if err != nil {
 			return err
@@ -356,3 +362,15 @@ func signatureEntries(root string) []Entry {
 
 	return sigEntries
 }
+
+// keywordEntries returns a slice of entries including a comment of the
+// keywords requested when generating this manifest.
+func keywordEntries(keywords []Keyword) []Entry {
+	// Convert all of the keywords to zero-value keyvals.
+	return []Entry{
+		{
+			Type: CommentType,
+			Raw:  fmt.Sprintf("#%16s%s", "keywords: ", strings.Join(FromKeywords(keywords), ",")),
+		},
+	}
+}