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Commit f5b3a01e authored by Adam Lesinski's avatar Adam Lesinski
Browse files

Add fastpath for single signature comparison 

PackageManager does not need to create a hash set
when comparing two sets of signatures, where each set
contains one signature. This is the common case for
most applications.

Bug:13029313
Change-Id: I61883d85960db7b376e234d7abae6149c4d20245
parent 3d9bcb90

services/core/java/com/android/server/pm/PackageManagerService.java

+26 −0
Original line number Diff line number Diff line
@@ -2546,15 +2546,41 @@ public class PackageManagerService extends IPackageManager.Stub { 
        }

    }



    /**

     * Compares two sets of signatures. Returns:

     * <br />

     * {@link PackageManager#SIGNATURE_NEITHER_SIGNED}: if both signature sets are null,

     * <br />

     * {@link PackageManager#SIGNATURE_FIRST_NOT_SIGNED}: if the first signature set is null,

     * <br />

     * {@link PackageManager#SIGNATURE_SECOND_NOT_SIGNED}: if the second signature set is null,

     * <br />

     * {@link PackageManager#SIGNATURE_MATCH}: if the two signature sets are identical,

     * <br />

     * {@link PackageManager#SIGNATURE_NO_MATCH}: if the two signature sets differ.

     */

    static int compareSignatures(Signature[] s1, Signature[] s2) {

        if (s1 == null) {

            return s2 == null

                    ? PackageManager.SIGNATURE_NEITHER_SIGNED

                    : PackageManager.SIGNATURE_FIRST_NOT_SIGNED;

        }



        if (s2 == null) {

            return PackageManager.SIGNATURE_SECOND_NOT_SIGNED;

        }



        if (s1.length != s2.length) {

            return PackageManager.SIGNATURE_NO_MATCH;

        }



        // Since both signature sets are of size 1, we can compare without HashSets.

        if (s1.length == 1) {

            return s1[0].equals(s2[0]) ?

                    PackageManager.SIGNATURE_MATCH :

                    PackageManager.SIGNATURE_NO_MATCH;

        }



        HashSet<Signature> set1 = new HashSet<Signature>();

        for (Signature sig : s1) {

            set1.add(sig);