Introduce a util method PrettyConcat
The method can be used when printing string list in a well-formated way
in user-facing messages.
This will be used in a follow up change.
Test: m nothing --no-skip-soong-tests
Change-Id: I77e3445a5333f82067dd8f1bb6ad892c69754ece
diff --git a/android/util.go b/android/util.go
index 3c0af2f..2d269b7 100644
--- a/android/util.go
+++ b/android/util.go
@@ -177,6 +177,41 @@
return m
}
+// PrettyConcat returns the formatted concatenated string suitable for displaying user-facing
+// messages.
+func PrettyConcat(list []string, quote bool, lastSep string) string {
+ if len(list) == 0 {
+ return ""
+ }
+
+ quoteStr := func(v string) string {
+ if !quote {
+ return v
+ }
+ return fmt.Sprintf("%q", v)
+ }
+
+ if len(list) == 1 {
+ return quoteStr(list[0])
+ }
+
+ var sb strings.Builder
+ for i, val := range list {
+ if i > 0 {
+ sb.WriteString(", ")
+ }
+ if i == len(list)-1 {
+ sb.WriteString(lastSep)
+ if lastSep != "" {
+ sb.WriteString(" ")
+ }
+ }
+ sb.WriteString(quoteStr(val))
+ }
+
+ return sb.String()
+}
+
// ListSetDifference checks if the two lists contain the same elements. It returns
// a boolean which is true if there is a difference, and then returns lists of elements
// that are in l1 but not l2, and l2 but not l1.
diff --git a/android/util_test.go b/android/util_test.go
index 6537d69..b76ffcf 100644
--- a/android/util_test.go
+++ b/android/util_test.go
@@ -867,3 +867,51 @@
})
}
}
+
+var prettyConcatTestCases = []struct {
+ name string
+ list []string
+ quote bool
+ lastSeparator string
+ expected string
+}{
+ {
+ name: "empty",
+ list: []string{},
+ quote: false,
+ lastSeparator: "and",
+ expected: ``,
+ },
+ {
+ name: "single",
+ list: []string{"a"},
+ quote: true,
+ lastSeparator: "and",
+ expected: `"a"`,
+ },
+ {
+ name: "with separator",
+ list: []string{"a", "b", "c"},
+ quote: true,
+ lastSeparator: "or",
+ expected: `"a", "b", or "c"`,
+ },
+ {
+ name: "without separator",
+ list: []string{"a", "b", "c"},
+ quote: false,
+ lastSeparator: "",
+ expected: `a, b, c`,
+ },
+}
+
+func TestPrettyConcat(t *testing.T) {
+ for _, testCase := range prettyConcatTestCases {
+ t.Run(testCase.name, func(t *testing.T) {
+ concatString := PrettyConcat(testCase.list, testCase.quote, testCase.lastSeparator)
+ if !reflect.DeepEqual(concatString, testCase.expected) {
+ t.Errorf("expected %#v, got %#v", testCase.expected, concatString)
+ }
+ })
+ }
+}