Add CopyOf utility method
Add a utility method that returns a copy of a slice of strings.
This is primarily useful when appending to a string slice to avoid
accidentally reusing the backing array.
Test: util_test.go
Change-Id: I7801fc7ca19e27ddc9f1b1b452788b723c7f619c
diff --git a/android/util.go b/android/util.go
index 92ab845..8fc159d 100644
--- a/android/util.go
+++ b/android/util.go
@@ -20,6 +20,11 @@
"strings"
)
+// CopyOf returns a new slice that has the same contents as s.
+func CopyOf(s []string) []string {
+ return append([]string(nil), s...)
+}
+
func JoinWithPrefix(strs []string, prefix string) string {
if len(strs) == 0 {
return ""
diff --git a/android/util_test.go b/android/util_test.go
index 1c791b2..2e5eb07 100644
--- a/android/util_test.go
+++ b/android/util_test.go
@@ -15,6 +15,7 @@
package android
import (
+ "fmt"
"reflect"
"testing"
)
@@ -359,3 +360,47 @@
})
}
}
+
+func ExampleCopyOf() {
+ a := []string{"1", "2", "3"}
+ b := CopyOf(a)
+ a[0] = "-1"
+ fmt.Printf("a = %q\n", a)
+ fmt.Printf("b = %q\n", b)
+
+ // Output:
+ // a = ["-1" "2" "3"]
+ // b = ["1" "2" "3"]
+}
+
+func ExampleCopyOf_append() {
+ a := make([]string, 1, 2)
+ a[0] = "foo"
+
+ fmt.Println("Without CopyOf:")
+ b := append(a, "bar")
+ c := append(a, "baz")
+ fmt.Printf("a = %q\n", a)
+ fmt.Printf("b = %q\n", b)
+ fmt.Printf("c = %q\n", c)
+
+ a = make([]string, 1, 2)
+ a[0] = "foo"
+
+ fmt.Println("With CopyOf:")
+ b = append(CopyOf(a), "bar")
+ c = append(CopyOf(a), "baz")
+ fmt.Printf("a = %q\n", a)
+ fmt.Printf("b = %q\n", b)
+ fmt.Printf("c = %q\n", c)
+
+ // Output:
+ // Without CopyOf:
+ // a = ["foo"]
+ // b = ["foo" "baz"]
+ // c = ["foo" "baz"]
+ // With CopyOf:
+ // a = ["foo"]
+ // b = ["foo" "bar"]
+ // c = ["foo" "baz"]
+}
diff --git a/dexpreopt/dexpreopt.go b/dexpreopt/dexpreopt.go
index eacb86a..7fdfb49 100644
--- a/dexpreopt/dexpreopt.go
+++ b/dexpreopt/dexpreopt.go
@@ -578,9 +578,7 @@
}
}
-func copyOf(l []string) []string {
- return append([]string(nil), l...)
-}
+var copyOf = android.CopyOf
func anyHavePrefix(l []string, prefix string) bool {
for _, x := range l {