[lxc-devel] [lxd/master] Fix crash when sorting images with custom columns

[albertodonato on Github]

A non-text attachment was scrubbed...
Name: not available
Type: text/x-mailbox
Size: 445 bytes
Desc: not available
URL: <http://lists.linuxcontainers.org/pipermail/lxc-devel/attachments/20170615/a8abc93b/attachment.bin>
-------------- next part --------------
From 4080e481f45ec14ec1b339664145f50af680ecb6 Mon Sep 17 00:00:00 2001
From: Alberto Donato <alberto.donato at canonical.com>
Date: Thu, 15 Jun 2017 10:05:17 +0200
Subject: [PATCH] Fix crash when sorting images with custom columns.

Signed-off-by: Alberto Donato <alberto.donato at canonical.com>
---
 lxc/config.go     |  2 +-
 lxc/image.go      |  4 ++--
 lxc/utils.go      | 28 +++++++++++-----------------
 lxc/utils_test.go | 37 +++++++++++++++++++++++++++++++++++++
 4 files changed, 51 insertions(+), 20 deletions(-)
 create mode 100644 lxc/utils_test.go

diff --git a/lxc/config.go b/lxc/config.go
index 7be59aca8..884736828 100644
--- a/lxc/config.go
+++ b/lxc/config.go
@@ -310,7 +310,7 @@ func (c *configCmd) run(config *lxd.Config, args []string) error {
 				i18n.G("COMMON NAME"),
 				i18n.G("ISSUE DATE"),
 				i18n.G("EXPIRY DATE")})
-			sort.Sort(SortImage(data))
+			sort.Sort(StringList(data))
 			table.AppendBulk(data)
 			table.Render()
 
diff --git a/lxc/image.go b/lxc/image.go
index 377cfaf63..bc2526124 100644
--- a/lxc/image.go
+++ b/lxc/image.go
@@ -744,7 +744,7 @@ func (c *imageCmd) showImages(images []api.Image, filters []string, columns []im
 			data = append(data, row)
 		}
 
-		sort.Sort(SortImage(data))
+		sort.Sort(StringList(data))
 		return data
 	}
 
@@ -814,7 +814,7 @@ func (c *imageCmd) showAliases(aliases []api.ImageAliasesEntry, filters []string
 		i18n.G("ALIAS"),
 		i18n.G("FINGERPRINT"),
 		i18n.G("DESCRIPTION")})
-	sort.Sort(SortImage(data))
+	sort.Sort(StringList(data))
 	table.AppendBulk(data)
 	table.Render()
 
diff --git a/lxc/utils.go b/lxc/utils.go
index 96d74d7a3..24e64a0ce 100644
--- a/lxc/utils.go
+++ b/lxc/utils.go
@@ -74,39 +74,33 @@ func (p *ProgressRenderer) UpdateOp(op api.Operation) {
 	}
 }
 
-// Image fingerprint and alias sorting
-type SortImage [][]string
+type StringList [][]string
 
-func (a SortImage) Len() int {
+func (a StringList) Len() int {
 	return len(a)
 }
 
-func (a SortImage) Swap(i, j int) {
+func (a StringList) Swap(i, j int) {
 	a[i], a[j] = a[j], a[i]
 }
 
-func (a SortImage) Less(i, j int) bool {
-	if a[i][0] == a[j][0] {
-		if a[i][3] == "" {
-			return false
-		}
-
-		if a[j][3] == "" {
-			return true
+func (a StringList) Less(i, j int) bool {
+	x := 0
+	for x, _ = range a[i] {
+		if a[i][x] != a[j][x] {
+			break
 		}
-
-		return a[i][3] < a[j][3]
 	}
 
-	if a[i][0] == "" {
+	if a[i][x] == "" {
 		return false
 	}
 
-	if a[j][0] == "" {
+	if a[j][x] == "" {
 		return true
 	}
 
-	return a[i][0] < a[j][0]
+	return a[i][x] < a[j][x]
 }
 
 // Container name sorting
diff --git a/lxc/utils_test.go b/lxc/utils_test.go
new file mode 100644
index 000000000..cd11ad829
--- /dev/null
+++ b/lxc/utils_test.go
@@ -0,0 +1,37 @@
+package main
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type utilsTestSuite struct {
+	suite.Suite
+}
+
+func TestUtilsTestSuite(t *testing.T) {
+	suite.Run(t, new(utilsTestSuite))
+}
+
+// StringList can be used to sort a list of strings.
+func (s *utilsTestSuite) Test_StringList() {
+	data := [][]string{{"foo", "bar"}, {"baz", "bza"}}
+	sort.Sort(StringList(data))
+	s.Equal([][]string{{"baz", "bza"}, {"foo", "bar"}}, data)
+}
+
+// The first different string is used in sorting.
+func (s *utilsTestSuite) Test_StringList_sort_by_column() {
+	data := [][]string{{"foo", "baz"}, {"foo", "bar"}}
+	sort.Sort(StringList(data))
+	s.Equal([][]string{{"foo", "bar"}, {"foo", "baz"}}, data)
+}
+
+// Empty strings are sorted last.
+func (s *utilsTestSuite) Test_StringList_empty_strings() {
+	data := [][]string{{"", "bar"}, {"foo", "baz"}}
+	sort.Sort(StringList(data))
+	s.Equal([][]string{{"foo", "baz"}, {"", "bar"}}, data)
+}