Minor changes to the LinkAddress API docs.

1. Rename getNetworkPrefixLength to getPrefixLength. Update all
   callers in frameworks/base and add a shim method and a TODO
   for the rest.
2. @hide isSameAddressAs. It doesn't add much, and it's just
   one-liner that callers can implement if they want.
3. Fix the alignment of the initial paragraph (<ul> should have
   been </ul>).
4. Remove the documentation that talks about creating
   LinkAddresses, since there's no public API for creating them.

With these changes I think LinkAddress is fine as a public API.

Bug: 15142362
Change-Id: Iaf3b1db577745bb68a9e1dd7f96d666dd3f3ec7c

core/java/android/net/LinkAddress.java

@@ -39,18 +39,13 @@ import static android.system.OsConstants.RT_SCOPE_UNIVERSE;
  * <ul>
  * <li>An IP address and prefix length (e.g., {@code 2001:db8::1/64} or {@code 192.0.2.1/24}).
  * The address must be unicast, as multicast addresses cannot be assigned to interfaces.
- * <li>Address flags: A bitmask of {@code IFA_F_*} values representing properties
+ * <li>Address flags: A bitmask of {@code OsConstants.IFA_F_*} values representing properties
- * of the address.
+ * of the address (e.g., {@code android.system.OsConstants.IFA_F_OPTIMISTIC}).
- * <li>Address scope: An integer defining the scope in which the address is unique (e.g.,
+ * <li>Address scope: One of the {@code OsConstants.IFA_F_*} values; defines the scope in which
- * {@code RT_SCOPE_LINK} or {@code RT_SCOPE_SITE}).
+ * the address is unique (e.g.,
- * <ul>
+ * {@code android.system.OsConstants.RT_SCOPE_LINK} or
- *<p>
+ * {@code android.system.OsConstants.RT_SCOPE_UNIVERSE}).
- * When constructing a {@code LinkAddress}, the IP address and prefix are required. The flags and
+ * </ul>
- * scope are optional. If they are not specified, the flags are set to zero, and the scope will be
- * determined based on the IP address (e.g., link-local addresses will be created with a scope of
- * {@code RT_SCOPE_LINK}, global addresses with {@code RT_SCOPE_UNIVERSE},
- * etc.) If they are specified, they are not checked for validity.
- *
  */
 public class LinkAddress implements Parcelable {
     /**
@@ -202,7 +197,9 @@ public class LinkAddress implements Parcelable {
 
     /**
      * Compares this {@code LinkAddress} instance against {@code obj}. Two addresses are equal if
-     * their address, prefix length, flags and scope are equal.
+     * their address, prefix length, flags and scope are equal. Thus, for example, two addresses
+     * that have the same address and prefix length are not equal if one of them is deprecated and
+     * the other is not.
      *
      * @param obj the object to be tested for equality.
      * @return {@code true} if both objects are equal, {@code false} otherwise.
@@ -236,6 +233,7 @@ public class LinkAddress implements Parcelable {
      * @param other the {@code LinkAddress} to compare to.
      * @return {@code true} if both objects have the same address and prefix length, {@code false}
      * otherwise.
+     * @hide
      */
     public boolean isSameAddressAs(LinkAddress other) {
         return address.equals(other.address) && prefixLength == other.prefixLength;
@@ -251,10 +249,19 @@ public class LinkAddress implements Parcelable {
     /**
      * Returns the prefix length of this {@code LinkAddress}.
      */
-    public int getNetworkPrefixLength() {
+    public int getPrefixLength() {
         return prefixLength;
     }
 
+    /**
+     * Returns the prefix length of this {@code LinkAddress}.
+     * TODO: Delete all callers and remove in favour of getPrefixLength().
+     * @hide
+     */
+    public int getNetworkPrefixLength() {
+        return getPrefixLength();
+    }
+
     /**
      * Returns the flags of this {@code LinkAddress}.
      */

core/java/android/net/RouteInfo.java

@@ -119,7 +119,7 @@ public class RouteInfo implements Parcelable {
         mHasGateway = (!gateway.isAnyLocalAddress());
 
         mDestination = new LinkAddress(NetworkUtils.getNetworkPart(destination.getAddress(),
-                destination.getNetworkPrefixLength()), destination.getNetworkPrefixLength());
+                destination.getPrefixLength()), destination.getPrefixLength());
         if ((destination.getAddress() instanceof Inet4Address &&
                  (gateway instanceof Inet4Address == false)) ||
                 (destination.getAddress() instanceof Inet6Address &&
@@ -210,18 +210,18 @@ public class RouteInfo implements Parcelable {
 
     private boolean isHost() {
         return (mDestination.getAddress() instanceof Inet4Address &&
-                mDestination.getNetworkPrefixLength() == 32) ||
+                mDestination.getPrefixLength() == 32) ||
                (mDestination.getAddress() instanceof Inet6Address &&
-                mDestination.getNetworkPrefixLength() == 128);
+                mDestination.getPrefixLength() == 128);
     }
 
     private boolean isDefault() {
         boolean val = false;
         if (mGateway != null) {
             if (mGateway instanceof Inet4Address) {
-                val = (mDestination == null || mDestination.getNetworkPrefixLength() == 0);
+                val = (mDestination == null || mDestination.getPrefixLength() == 0);
             } else {
-                val = (mDestination == null || mDestination.getNetworkPrefixLength() == 0);
+                val = (mDestination == null || mDestination.getPrefixLength() == 0);
             }
         }
         return val;
@@ -306,7 +306,7 @@ public class RouteInfo implements Parcelable {
 
         // match the route destination and destination with prefix length
         InetAddress dstNet = NetworkUtils.getNetworkPart(destination,
-                mDestination.getNetworkPrefixLength());
+                mDestination.getPrefixLength());
 
         return mDestination.getAddress().equals(dstNet);
     }
@@ -328,8 +328,8 @@ public class RouteInfo implements Parcelable {
         for (RouteInfo route : routes) {
             if (NetworkUtils.addressTypeMatches(route.mDestination.getAddress(), dest)) {
                 if ((bestRoute != null) &&
-                        (bestRoute.mDestination.getNetworkPrefixLength() >=
+                        (bestRoute.mDestination.getPrefixLength() >=
-                        route.mDestination.getNetworkPrefixLength())) {
+                        route.mDestination.getPrefixLength())) {
                     continue;
                 }
                 if (route.matches(dest)) bestRoute = route;
@@ -394,7 +394,7 @@ public class RouteInfo implements Parcelable {
         } else {
             dest.writeByte((byte) 1);
             dest.writeByteArray(mDestination.getAddress().getAddress());
-            dest.writeInt(mDestination.getNetworkPrefixLength());
+            dest.writeInt(mDestination.getPrefixLength());
         }
 
         if (mGateway == null) {

core/tests/coretests/src/android/net/LinkAddressTest.java

@@ -56,26 +56,26 @@ public class LinkAddressTest extends AndroidTestCase {
         // Valid addresses work as expected.
         address = new LinkAddress(V4_ADDRESS, 25);
         assertEquals(V4_ADDRESS, address.getAddress());
-        assertEquals(25, address.getNetworkPrefixLength());
+        assertEquals(25, address.getPrefixLength());
         assertEquals(0, address.getFlags());
         assertEquals(RT_SCOPE_UNIVERSE, address.getScope());
 
         address = new LinkAddress(V6_ADDRESS, 127);
         assertEquals(V6_ADDRESS, address.getAddress());
-        assertEquals(127, address.getNetworkPrefixLength());
+        assertEquals(127, address.getPrefixLength());
         assertEquals(0, address.getFlags());
         assertEquals(RT_SCOPE_UNIVERSE, address.getScope());
 
         // Nonsensical flags/scopes or combinations thereof are acceptable.
         address = new LinkAddress(V6 + "/64", IFA_F_DEPRECATED | IFA_F_PERMANENT, RT_SCOPE_LINK);
         assertEquals(V6_ADDRESS, address.getAddress());
-        assertEquals(64, address.getNetworkPrefixLength());
+        assertEquals(64, address.getPrefixLength());
         assertEquals(IFA_F_DEPRECATED | IFA_F_PERMANENT, address.getFlags());
         assertEquals(RT_SCOPE_LINK, address.getScope());
 
         address = new LinkAddress(V4 + "/23", 123, 456);
         assertEquals(V4_ADDRESS, address.getAddress());
-        assertEquals(23, address.getNetworkPrefixLength());
+        assertEquals(23, address.getPrefixLength());
         assertEquals(123, address.getFlags());
         assertEquals(456, address.getScope());
 
@@ -94,10 +94,10 @@ public class LinkAddressTest extends AndroidTestCase {
         }
 
         assertEquals(NetworkUtils.numericToInetAddress("127.0.0.1"), ipv4Loopback.getAddress());
-        assertEquals(8, ipv4Loopback.getNetworkPrefixLength());
+        assertEquals(8, ipv4Loopback.getPrefixLength());
 
         assertEquals(NetworkUtils.numericToInetAddress("::1"), ipv6Loopback.getAddress());
-        assertEquals(128, ipv6Loopback.getNetworkPrefixLength());
+        assertEquals(128, ipv6Loopback.getPrefixLength());
 
         // Null addresses are rejected.
         try {

services/core/java/com/android/server/ConnectivityService.java

@@ -1669,7 +1669,7 @@ public class ConnectivityService extends IConnectivityManager.Stub {
                         continue;
                     }
 
-                    int prefix = destination.getNetworkPrefixLength();
+                    int prefix = destination.getPrefixLength();
                     InetAddress addrMasked = NetworkUtils.getNetworkPart(address, prefix);
                     InetAddress destMasked = NetworkUtils.getNetworkPart(destination.getAddress(),
                             prefix);