Merge "Work-around for system property failures" into tm-qpr-dev (1b9cdb02) · Commits · e / os / android_frameworks_base

core/java/android/app/PropertyInvalidatedCache.java

+42 −1

Original line number	Diff line number	Diff line
		@@ -309,6 +309,21 @@ public class PropertyInvalidatedCache<Query, Result> {
		*/
		public static final String MODULE_TELEPHONY = "telephony";

		/**
		* Constants that affect retries when the process is unable to write the property.
		* The first constant is the number of times the process will attempt to set the
		* property. The second constant is the delay between attempts.
		*/

		/**
		* Wait 200ms between retry attempts and the retry limit is 5. That gives a total possible
		* delay of 1s, which should be less than ANR timeouts. The goal is to have the system crash
		* because the property could not be set (which is a condition that is easily recognized) and
		* not crash because of an ANR (which can be confusing to debug).
		*/
		private static final int PROPERTY_FAILURE_RETRY_DELAY_MILLIS = 200;
		private static final int PROPERTY_FAILURE_RETRY_LIMIT = 5;

		/**
		* Construct a system property that matches the rules described above. The module is
		* one of the permitted values above. The API is a string that is a legal Java simple
		@@ -670,7 +685,33 @@ public class PropertyInvalidatedCache<Query, Result> {
		}
		}
		}
		RuntimeException failure = null;
		for (int attempt = 0; attempt < PROPERTY_FAILURE_RETRY_LIMIT; attempt++) {
		try {
		SystemProperties.set(name, Long.toString(val));
		if (attempt > 0) {
		// This log is not guarded. Based on known bug reports, it should
		// occur once a week or less. The purpose of the log message is to
		// identify the retries as a source of delay that might be otherwise
		// be attributed to the cache itself.
		Log.w(TAG, "Nonce set after " + attempt + " tries");
		}
		return;
		} catch (RuntimeException e) {
		if (failure == null) {
		failure = e;
		}
		try {
		Thread.sleep(PROPERTY_FAILURE_RETRY_DELAY_MILLIS);
		} catch (InterruptedException x) {
		// Ignore this exception. The desired delay is only approximate and
		// there is no issue if the sleep sometimes terminates early.
		}
		}
		}
		// This point is reached only if SystemProperties.set() fails at least once.
		// Rethrow the first exception that was received.
		throw failure;
		}

		// Set the nonce in a static context. No handle is available.