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Commit 49f7afe6 authored by chloedai's avatar chloedai Committed by Chloe Dai
Browse files

Add tag availability checking mechanism 

Set a cookie to the tag objects when they are constructed, the
cookie could be used to check the availability before returning
the tag service

Bug: 199291025
Test: test with some reader apps, test pass
Change-Id: Iabaab1f6d2d22e15966d31dd79099369d828f4c6
parent 7f994312

core/java/android/nfc/INfcTag.aidl

+3 −0
Original line number Diff line number Diff line
@@ -45,4 +45,7 @@ interface INfcTag 
    boolean canMakeReadOnly(int ndefType);

    int getMaxTransceiveLength(int technology);

    boolean getExtendedLengthApdusSupported();



    void setTagUpToDate(long cookie);

    boolean isTagUpToDate(long cookie);

}

core/java/android/nfc/Tag.java

+21 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ import android.os.Bundle; 
import android.os.Parcel;

import android.os.Parcelable;

import android.os.RemoteException;

import android.os.SystemClock;



import java.io.IOException;

import java.util.Arrays;
@@ -121,6 +122,7 @@ public final class Tag implements Parcelable { 
    final INfcTag mTagService; // interface to NFC service, will be null if mock tag



    int mConnectedTechnology;

    long mCookie;



    /**

     * Hidden constructor to be used by NFC service and internal classes.
@@ -140,6 +142,13 @@ public final class Tag implements Parcelable { 
        mTagService = tagService;



        mConnectedTechnology = -1;



        try {

            mCookie = SystemClock.elapsedRealtime();

            tagService.setTagUpToDate(mCookie);

        } catch (RemoteException e) {

            throw e.rethrowAsRuntimeException();

        }

    }



    /**
@@ -361,6 +370,18 @@ public final class Tag implements Parcelable { 
    /** @hide */

    @UnsupportedAppUsage

    public INfcTag getTagService() {

        try {

            if (!mTagService.isTagUpToDate(mCookie)) {

                String id_str = "";

                for (int i = 0; i < mId.length; i++) {

                    id_str = id_str + String.format("%02X ", mId[i]);

                }

                String msg = "Permission Denial: Tag ( ID: " + id_str + ") is out of date";

                throw new SecurityException(msg);

            }

        } catch (RemoteException e) {

            throw e.rethrowAsRuntimeException();

        }

        return mTagService;

    }