Merge "Remove several locks in PropertyInvalidatedCache" into main (c7fd0ccf) · Commits · e / os / android_frameworks_base

core/java/android/app/PropertyInvalidatedCache.java

+20 −14

Original line number	Diff line number	Diff line
		@@ -668,8 +668,10 @@ public class PropertyInvalidatedCache<Query, Result> {

		// True if this handler is in test mode. If it is in test mode, then nonces are stored
		// and retrieved from mTestNonce.
		// Note that we use volatile to avoid the need to take a lock on hot paths for any reads,
		// but we still protect functional reads/writes by the lock.
		@GuardedBy("mLock")
		private boolean mTestMode;
		private volatile boolean mTestMode;

		// This is the local value of the nonce, as last set by the NonceHandler. It is always
		// updated by the setNonce() operation. The getNonce() operation returns this value in
		@@ -703,8 +705,13 @@ public class PropertyInvalidatedCache<Query, Result> {
		* the local mShadowNonce.
		*/
		long getNonce() {
		// As this get is on many critical hot paths, avoid the test-specific lock if possible.
		if (mTestMode) {
		synchronized (mLock) {
		if (mTestMode) return mShadowNonce;
		if (mTestMode) {
		return mShadowNonce;
		}
		}
		}
		return getNonceInternal();
		}
		@@ -2435,8 +2442,10 @@ public class PropertyInvalidatedCache<Query, Result> {
		// The highest string index extracted from the string block. -1 means no strings have
		// been seen. This is used to skip strings that have already been processed, when the
		// string block is updated.
		// Note that we also mark this volatile to avoid needing the lock when fetching the nonce
		// and validating the index, which is safe as this value is monotonically increasing.
		@GuardedBy("mLock")
		private int mHighestIndex = -1;
		private volatile int mHighestIndex = -1;

		// The number bytes of the string block that has been used. This is a statistics.
		@GuardedBy("mLock")
		@@ -2533,7 +2542,6 @@ public class PropertyInvalidatedCache<Query, Result> {
		// Throw an exception if the nonce handle is invalid. The handle is bad if it is out of
		// range of allocated handles. Note that NONCE_HANDLE_INVALID will throw: this is
		// important for setNonce().
		@GuardedBy("mLock")
		private void throwIfBadHandle(int handle) {
		if (handle < 0 \|\| handle > mHighestIndex) {
		throw new IllegalArgumentException("invalid nonce handle: " + handle);
		@@ -2588,19 +2596,17 @@ public class PropertyInvalidatedCache<Query, Result> {

		// Thin wrapper around the native method.
		public boolean setNonce(int handle, long value) {
		synchronized (mLock) {
		// No lock needed as the underlying write is guarded with an atomic.
		throwIfBadHandle(handle);
		throwIfImmutable();
		return nativeSetNonce(mPtr, handle, value);
		}
		}

		public long getNonce(int handle) {
		synchronized (mLock) {
		// No lock needed as the underlying read is guarded with an atomic.
		throwIfBadHandle(handle);
		return nativeGetNonce(mPtr, handle);
		}
		}

		/**
		* Dump the nonce statistics