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Commit 6e0280d7 authored by Jihoon Kang's avatar Jihoon Kang
Browse files

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
parent 2261a82d

android/util.go

+35 −0
Original line number Diff line number Diff line
@@ -177,6 +177,41 @@ func setFromList[T comparable](l []T) map[T]bool { 
	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.

android/util_test.go

+48 −0
Original line number Diff line number Diff line
@@ -867,3 +867,51 @@ func TestHasIntersection(t *testing.T) { 
		})

	}

}



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)

			}

		})

	}

}