Distinguish unspecified and explicit null values in resources

BUG: 17919345
Change-Id: Ic4f04f7dd0f986f58a749b5950d80c1cfdb074ea

1 files changed, 10 insertions, 1 deletions

diff --git a/include/androidfw/ResourceTypes.h b/include/androidfw/ResourceTypes.h
index ac5eca08..85e442d 100644
--- a/include/androidfw/ResourceTypes.h
+++ b/include/androidfw/ResourceTypes.h
@@ -253,7 +253,8 @@ struct Res_value
         
     // Type of the data value.
     enum {
-        // Contains no data.
+        // The 'data' is either 0 or 1, specifying this resource is either
+        // undefined or empty, respectively.
         TYPE_NULL = 0x00,
         // The 'data' holds a ResTable_ref, a reference to another resource
         // table entry.
@@ -351,6 +352,14 @@ struct Res_value
         COMPLEX_MANTISSA_MASK = 0xffffff
     };
 
+    // Possible data values for TYPE_NULL.
+    enum {
+        // The value is not defined.
+        DATA_NULL_UNDEFINED = 0,
+        // The value is explicitly defined as empty.
+        DATA_NULL_EMPTY = 1
+    };
+
     // The data for this item, as interpreted according to dataType.
     uint32_t data;