Preventing recursive referrence in drawables am: 99b25d2817 (b2985209) · Commits · e / os / android_frameworks_base

core/java/android/content/res/ResourcesImpl.java

+55 −11

Original line number	Diff line number	Diff line
		@@ -49,6 +49,8 @@ import android.util.TypedValue;
		import android.util.Xml;
		import android.view.DisplayAdjustments;

		import com.android.internal.util.GrowingArrayUtils;

		import org.xmlpull.v1.XmlPullParser;
		import org.xmlpull.v1.XmlPullParserException;

		@@ -117,6 +119,13 @@ public class ResourcesImpl {
		private final ConfigurationBoundResourceCache<StateListAnimator> mStateListAnimatorCache =
		new ConfigurationBoundResourceCache<>();

		// A stack of all the resourceIds already referenced when parsing a resource. This is used to
		// detect circular references in the xml.
		// Using a ThreadLocal variable ensures that we have different stacks for multiple parallel
		// calls to ResourcesImpl
		private final ThreadLocal<LookupStack> mLookupStack =
		ThreadLocal.withInitial(() -> new LookupStack());

		/** Size of the cyclical cache used to map XML files to blocks. */
		private static final int XML_BLOCK_CACHE_SIZE = 4;

		@@ -784,6 +793,13 @@ public class ResourcesImpl {
		final Drawable dr;

		Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, file);
		LookupStack stack = mLookupStack.get();
		try {
		// Perform a linear search to check if we have already referenced this resource before.
		if (stack.contains(id)) {
		throw new Exception("Recursive reference in drawable");
		}
		stack.push(id);
		try {
		if (file.endsWith(".xml")) {
		final XmlResourceParser rp = loadXmlResourceParser(
		@@ -796,7 +812,10 @@ public class ResourcesImpl {
		dr = Drawable.createFromResourceStream(wrapper, value, is, file, null);
		is.close();
		}
		} catch (Exception \| StackOverflowError e) {
		} finally {
		stack.pop();
		}
		} catch (Exception e) {
		Trace.traceEnd(Trace.TRACE_TAG_RESOURCES);
		final NotFoundException rnf = new NotFoundException(
		"File " + file + " from drawable resource ID #0x" + Integer.toHexString(id));
		@@ -1377,4 +1396,29 @@ public class ResourcesImpl {
		}
		}
		}

		private static class LookupStack {

		// Pick a reasonable default size for the array, it is grown as needed.
		private int[] mIds = new int[4];
		private int mSize = 0;

		public void push(int id) {
		mIds = GrowingArrayUtils.append(mIds, mSize, id);
		mSize++;
		}

		public boolean contains(int id) {
		for (int i = 0; i < mSize; i++) {
		if (mIds[i] == id) {
		return true;
		}
		}
		return false;
		}

		public void pop() {
		mSize--;
		}
		}
		}