Copy out returned string (and free it Rust-internal)

glean-core/android/src/main/java/mozilla/telemetry/glean/private/StringMetricType.kt

@@ -9,6 +9,7 @@ import com.sun.jna.StringArray
 import mozilla.telemetry.glean.Glean
 import mozilla.telemetry.glean.rust.LibGleanFFI
 import mozilla.telemetry.glean.rust.toByte
+import mozilla.telemetry.glean.rust.getAndConsumeRustString
 
 import mozilla.telemetry.glean.Dispatchers
 // import mozilla.components.service.glean.storages.StringsStorageEngine
@@ -84,11 +85,10 @@ class StringMetricType(
     @VisibleForTesting(otherwise = VisibleForTesting.NONE)
     fun testHasValue(pingName: String = sendInPings.first()): Boolean {
         /*@Suppress("EXPERIMENTAL_API_USAGE")
-        Dispatchers.API.assertInTestingMode()
+        Dispatchers.API.assertInTestingMode()*/
 
-        return StringsStorageEngine.getSnapshot(pingName, false)?.get(identifier) != null*/
-        assert(false, { "Testing API not implementated for StringMetricType" })
-        return false
+        val res = LibGleanFFI.INSTANCE.glean_string_test_has_value(Glean.handle, this.handle, pingName)
+        return res != 0.toByte()
     }
 
     /**
@@ -104,10 +104,12 @@ class StringMetricType(
     @VisibleForTesting(otherwise = VisibleForTesting.NONE)
     fun testGetValue(pingName: String = sendInPings.first()): String {
         /*@Suppress("EXPERIMENTAL_API_USAGE")
-        Dispatchers.API.assertInTestingMode()
+        Dispatchers.API.assertInTestingMode()*/
 
-        return StringsStorageEngine.getSnapshot(pingName, false)!![identifier]!!*/
-        assert(false, { "Testing API not implementated for StringMetricType" })
-        return "asd"
+        if (!testHasValue(pingName)) {
+            throw NullPointerException()
+        }
+        val ptr = LibGleanFFI.INSTANCE.glean_string_test_get_value(Glean.handle, this.handle, pingName)!!
+        return ptr.getAndConsumeRustString()
     }
 }

glean-core/android/src/main/java/mozilla/telemetry/glean/rust/LibGleanFFI.kt

@@ -15,6 +15,28 @@ import java.lang.reflect.Proxy
 // Turn a boolean into its Byte (u8) representation
 internal fun Boolean.toByte(): Byte = if (this) 1 else 0
 
+/**
+ * Helper to read a null terminated String out of the Pointer and free it.
+ *
+ * Important: Do not use this pointer after this! For anything!
+ */
+internal fun Pointer.getAndConsumeRustString(): String {
+    try {
+        return this.getRustString()
+    } finally {
+        LibGleanFFI.INSTANCE.glean_str_free(this)
+    }
+}
+
+/**
+ * Helper to read a null terminated string out of the pointer.
+ *
+ * Important: doesn't free the pointer, use [getAndConsumeRustString] for that!
+ */
+internal fun Pointer.getRustString(): String {
+    return this.getString(0, "utf8")
+}
+
 @Suppress("TooManyFunctions")
 internal interface LibGleanFFI : Library {
     companion object {

glean-core/android/src/main/java/mozilla/telemetry/glean/rust/RustError.kt

@@ -67,25 +67,3 @@ internal open class RustError : Structure() {
         return Arrays.asList("code", "message")
     }
 }
-
-/**
- * Helper to read a null terminated String out of the Pointer and free it.
- *
- * Important: Do not use this pointer after this! For anything!
- */
-internal fun Pointer.getAndConsumeRustString(): String {
-    try {
-        return this.getRustString()
-    } finally {
-        LibGleanFFI.INSTANCE.glean_str_free(this)
-    }
-}
-
-/**
- * Helper to read a null terminated string out of the pointer.
- *
- * Important: doesn't free the pointer, use [getAndConsumeRustString] for that!
- */
-internal fun Pointer.getRustString(): String {
-    return this.getString(0, "utf8")
-}