isValidSlotId() and isValidPhoneId() updated to handle negatives.

The old version of the code wanted to just check to make sure
that the slot/phone id is greater than INVALID_SLOT_ID or
INVALID_PHONE_ID that are both currently defined to be -1000. The
changes are made for 2 reasons.  First, INVALID_SLOT_ID and/or
INVALID_PHONE_ID might not always be defined to be a negative value
so there is a big assumption.  Secondly, anything greater than
-1000 allows other negative values to be considered valid ids.

Bug: 17243556
Change-Id: I2bbfcc2cfd2d7c4772dfb9c50af2dc88c0f315e2

1 files changed, 10 insertions, 3 deletions

diff --git a/telephony/java/android/telephony/SubscriptionManager.java b/telephony/java/android/telephony/SubscriptionManager.java
index d0f355e..fe68263 100644
--- a/telephony/java/android/telephony/SubscriptionManager.java
+++ b/telephony/java/android/telephony/SubscriptionManager.java
@@ -930,13 +930,20 @@ public class SubscriptionManager implements BaseColumns {
 
     /** @hide */
     public static boolean isValidSlotId(int slotId) {
-        return slotId > INVALID_SLOT_ID && slotId < TelephonyManager.getDefault().getSimCount();
+        // We are testing INVALID_SLOT_ID and slotId >= 0 independently because we should
+        // not assume that INVALID_SLOT_ID will always be a negative value.  Any negative
+        // value is invalid.
+        return slotId != INVALID_SLOT_ID && slotId >= 0 &&
+                slotId < TelephonyManager.getDefault().getSimCount();
     }
 
     /** @hide */
     public static boolean isValidPhoneId(int phoneId) {
-        return phoneId > INVALID_PHONE_ID
-                && phoneId < TelephonyManager.getDefault().getPhoneCount();
+        // We are testing INVALID_PHONE_ID and phoneId >= 0 independently because we should
+        // not assume that INVALID_PHONE_ID will always be a negative value.  Any negative
+        // value is invalid.
+        return phoneId != INVALID_PHONE_ID && phoneId >= 0 &&
+                phoneId < TelephonyManager.getDefault().getPhoneCount();
     }
 
     /** @hide */