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Merge "Document Signature equals/hash should not include flags" into sc-dev

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This commit is contained in:
Michael Groover
2021-02-01 20:55:14 +00:00
committed by Android (Google) Code Review
parent db07cc3032 d8bd3028e3
commit 969c49681c
2 changed files with 30 additions and 0 deletions
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4
core/java/android/content/pm/Signature.java
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@@ -256,6 +256,8 @@ public class Signature implements Parcelable {
try {
if (obj != null) {
Signature other = (Signature)obj;
// Note, some classes, such as PackageParser.SigningDetails, rely on equals
// only comparing the mSignature arrays without the flags.
return this == other || Arrays.equals(mSignature, other.mSignature);
}
} catch (ClassCastException e) {
@@ -268,6 +270,8 @@ public class Signature implements Parcelable {
if (mHaveHashCode) {
return mHashCode;
}
// Note, similar to equals some classes rely on the hash code not including
// the flags for Set membership checks.
mHashCode = Arrays.hashCode(mSignature);
mHaveHashCode = true;
return mHashCode;

26
core/tests/coretests/src/android/content/pm/SignatureTest.java
View File

@@ -54,6 +54,32 @@ public class SignatureTest extends TestCase {
assertFalse(Signature.areEffectiveMatch(asArray(A, M), asArray(A, B)));
}
public void testHashCode_doesNotIncludeFlags() throws Exception {
// Some classes rely on the hash code not including the flags / capabilities for the signer
// to verify Set membership. This test verifies two signers with the same signature but
// different flags have the same hash code.
Signature signatureAWithAllCaps = new Signature(A.toCharsString());
// There are currently 5 capabilities that can be assigned to a previous signer, although
// for the purposes of this test all that matters is that the two flag values are distinct.
signatureAWithAllCaps.setFlags(31);
Signature signatureAWithNoCaps = new Signature(A.toCharsString());
signatureAWithNoCaps.setFlags(0);
assertEquals(signatureAWithAllCaps.hashCode(), signatureAWithNoCaps.hashCode());
}
public void testEquals_doesNotIncludeFlags() throws Exception {
// Similar to above some classes rely on equals only comparing the signature arrays
// for equality without including the flags. This test verifies two signers with the
// same signature but different flags are still considered equal.
Signature signatureAWithAllCaps = new Signature(A.toCharsString());
signatureAWithAllCaps.setFlags(31);
Signature signatureAWithNoCaps = new Signature(A.toCharsString());
signatureAWithNoCaps.setFlags(0);
assertEquals(signatureAWithAllCaps, signatureAWithNoCaps);
}
private static Signature[] asArray(Signature... s) {
return s;
}