Simplify EventLog (7ecb82e2) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/location/LocationManagerService.java

+1 −1

Original line number	Diff line number	Diff line
		@@ -1385,7 +1385,7 @@ public class LocationManagerService extends ILocationManager.Stub implements

		ipw.println("Event Log:");
		ipw.increaseIndent();
		EVENT_LOG.iterate(manager.getName(), ipw::println);
		EVENT_LOG.iterate(ipw::println, manager.getName());
		ipw.decreaseIndent();
		return;
		}

services/core/java/com/android/server/location/eventlog/LocalEventLog.java

+136 −161

Original line number	Diff line number	Diff line
		@@ -16,217 +16,193 @@

		package com.android.server.location.eventlog;

		import static java.lang.Integer.bitCount;

		import android.annotation.Nullable;
		import android.os.SystemClock;
		import android.util.TimeUtils;

		import com.android.internal.annotations.GuardedBy;
		import com.android.internal.util.Preconditions;

		import java.util.Iterator;
		import java.lang.reflect.Array;
		import java.util.Arrays;
		import java.util.NoSuchElementException;
		import java.util.function.Consumer;
		import java.util.Objects;

		/**
		* An in-memory event log to support historical event information.
		* An in-memory event log to support historical event information. The log is of a constant size,
		* and new events will overwrite old events as the log fills up.
		*
		* @param <T> log event type
		*/
		public abstract class LocalEventLog {
		public class LocalEventLog<T> {

		private interface Log {
		// true if this is a filler element that should not be queried
		boolean isFiller();
		long getTimeDeltaMs();
		String getLogString();
		boolean filter(@Nullable String filter);
		/**
		* Consumer of log events for iterating over the log.
		*
		* @param <T> log event type
		*/
		public interface LogConsumer<T> {
		/** Invoked with a time and a logEvent. */
		void acceptLog(long time, T logEvent);
		}

		private static final class FillerEvent implements Log {
		// masks for the entries field. 1 bit is used to indicate whether this is a filler event or not,
		// and 31 bits to store the time delta.
		private static final int IS_FILLER_MASK = 0b10000000000000000000000000000000;
		private static final int TIME_DELTA_MASK = 0b01111111111111111111111111111111;

		static final long MAX_TIME_DELTA = (1L << 32) - 1;
		private static final int IS_FILLER_OFFSET = countTrailingZeros(IS_FILLER_MASK);
		private static final int TIME_DELTA_OFFSET = countTrailingZeros(TIME_DELTA_MASK);

		private final int mTimeDelta;
		static final int MAX_TIME_DELTA = (1 << bitCount(TIME_DELTA_MASK)) - 1;

		FillerEvent(long timeDelta) {
		Preconditions.checkArgument(timeDelta >= 0);
		mTimeDelta = (int) timeDelta;
		private static int countTrailingZeros(int i) {
		int c = 0;
		while (i != 0 && (i & 1) == 0) {
		c++;
		i = i >>> 1;
		}

		@Override
		public boolean isFiller() {
		return true;
		return c;
		}

		@Override
		public long getTimeDeltaMs() {
		return Integer.toUnsignedLong(mTimeDelta);
		private static int createEntry(boolean isFiller, int timeDelta) {
		Preconditions.checkArgument(timeDelta >= 0 && timeDelta <= MAX_TIME_DELTA);
		return (((isFiller ? 1 : 0) << IS_FILLER_OFFSET) & IS_FILLER_MASK)
		\| ((timeDelta << TIME_DELTA_OFFSET) & TIME_DELTA_MASK);
		}

		@Override
		public String getLogString() {
		throw new AssertionError();
		static int getTimeDelta(int entry) {
		return (entry & TIME_DELTA_MASK) >>> TIME_DELTA_OFFSET;
		}

		@Override
		public boolean filter(String filter) {
		return false;
		}
		static boolean isFiller(int entry) {
		return (entry & IS_FILLER_MASK) != 0;
		}

		/**
		* An abstraction of a log event to be implemented by subclasses.
		*/
		public abstract static class LogEvent implements Log {
		// circular buffer of log entries and events. each entry corrosponds to the log event at the
		// same index. the log entry holds the filler status and time delta according to the bit masks
		// above, and the log event is the log event.

		static final long MAX_TIME_DELTA = (1L << 32) - 1;
		@GuardedBy("this")
		final int[] mEntries;

		private final int mTimeDelta;

		protected LogEvent(long timeDelta) {
		Preconditions.checkArgument(timeDelta >= 0);
		mTimeDelta = (int) timeDelta;
		}
		@GuardedBy("this")
		final @Nullable T[] mLogEvents;

		@Override
		public final boolean isFiller() {
		return false;
		}
		@GuardedBy("this")
		int mLogSize;

		@Override
		public final long getTimeDeltaMs() {
		return Integer.toUnsignedLong(mTimeDelta);
		}
		@GuardedBy("this")
		int mLogEndIndex;

		@Override
		public boolean filter(String filter) {
		return false;
		}
		}
		// invalid if log is empty

		// circular buffer of log entries
		private final Log[] mLog;
		private int mLogSize;
		private int mLogEndIndex;
		@GuardedBy("this")
		long mStartTime;

		// invalid if log is empty
		private long mStartRealtimeMs;
		private long mLastLogRealtimeMs;
		@GuardedBy("this")
		long mLastLogTime;

		public LocalEventLog(int size) {
		@SuppressWarnings("unchecked")
		public LocalEventLog(int size, Class<T> clazz) {
		Preconditions.checkArgument(size > 0);
		mLog = new Log[size];

		mEntries = new int[size];
		mLogEvents = (T[]) Array.newInstance(clazz, size);
		mLogSize = 0;
		mLogEndIndex = 0;

		mStartRealtimeMs = -1;
		mLastLogRealtimeMs = -1;
		}

		/**
		* Should be overridden by subclasses to return a new immutable log event for the given
		* arguments (as passed into {@link #addLogEvent(int, Object...)}.
		*/
		protected abstract LogEvent createLogEvent(long timeDelta, int event, Object... args);

		/**
		* May be optionally overridden by subclasses if they wish to change how log event time is
		* formatted.
		*/
		protected String getTimePrefix(long timeMs) {
		return TimeUtils.logTimeOfDay(timeMs) + ": ";
		mStartTime = -1;
		mLastLogTime = -1;
		}

		/**
		* Call to add a new log event at the current time. The arguments provided here will be passed
		* into {@link #createLogEvent(long, int, Object...)} in addition to a time delta, and should be
		* used to construct an appropriate {@link LogEvent} object.
		*/
		public synchronized void addLogEvent(int event, Object... args) {
		long timeMs = SystemClock.elapsedRealtime();
		/** Call to add a new log event at the given time. */
		protected synchronized void addLog(long time, T logEvent) {
		Preconditions.checkArgument(logEvent != null);

		// calculate delta
		long delta = 0;
		if (!isEmpty()) {
		delta = timeMs - mLastLogRealtimeMs;
		delta = time - mLastLogTime;

		// if the delta is invalid, or if the delta is great enough using filler elements would
		// if the delta is negative, or if the delta is great enough using filler elements would
		// result in an empty log anyways, just clear the log and continue, otherwise insert
		// filler elements until we have a reasonable delta
		if (delta < 0 \|\| (delta / FillerEvent.MAX_TIME_DELTA) >= mLog.length - 1) {
		if (delta < 0 \|\| (delta / MAX_TIME_DELTA) >= mEntries.length - 1) {
		clear();
		delta = 0;
		} else {
		while (delta >= LogEvent.MAX_TIME_DELTA) {
		long timeDelta = Math.min(FillerEvent.MAX_TIME_DELTA, delta);
		addLogEventInternal(new FillerEvent(timeDelta));
		delta -= timeDelta;
		while (delta >= MAX_TIME_DELTA) {
		addLogEventInternal(true, MAX_TIME_DELTA, null);
		delta -= MAX_TIME_DELTA;
		}
		}
		}

		// for first log entry, set initial times
		if (isEmpty()) {
		mStartRealtimeMs = timeMs;
		mLastLogRealtimeMs = mStartRealtimeMs;
		mStartTime = time;
		mLastLogTime = mStartTime;
		}

		addLogEventInternal(createLogEvent(delta, event, args));
		addLogEventInternal(false, (int) delta, logEvent);
		}

		private void addLogEventInternal(Log event) {
		Preconditions.checkState(mStartRealtimeMs != -1 && mLastLogRealtimeMs != -1);
		@GuardedBy("this")
		private void addLogEventInternal(boolean isFiller, int timeDelta, @Nullable T logEvent) {
		Preconditions.checkArgument(isFiller \|\| logEvent != null);
		Preconditions.checkState(mStartTime != -1 && mLastLogTime != -1);

		if (mLogSize == mLog.length) {
		if (mLogSize == mEntries.length) {
		// if log is full, size will remain the same, but update the start time
		mStartRealtimeMs += mLog[startIndex()].getTimeDeltaMs();
		mStartTime += getTimeDelta(mEntries[startIndex()]);
		} else {
		// otherwise add an item
		mLogSize++;
		}

		// set log and increment end index
		mLog[mLogEndIndex] = event;
		mEntries[mLogEndIndex] = createEntry(isFiller, timeDelta);
		mLogEvents[mLogEndIndex] = logEvent;
		mLogEndIndex = incrementIndex(mLogEndIndex);
		mLastLogRealtimeMs = mLastLogRealtimeMs + event.getTimeDeltaMs();
		mLastLogTime = mLastLogTime + timeDelta;
		}

		/** Clears the log of all entries. */
		public synchronized void clear() {
		// clear entries to allow gc
		Arrays.fill(mLogEvents, null);

		mLogEndIndex = 0;
		mLogSize = 0;

		mStartRealtimeMs = -1;
		mLastLogRealtimeMs = -1;
		mStartTime = -1;
		mLastLogTime = -1;
		}

		// checks if the log is empty (if empty, times are invalid)
		private synchronized boolean isEmpty() {
		@GuardedBy("this")
		private boolean isEmpty() {
		return mLogSize == 0;
		}

		/** Iterates over the event log, passing each log string to the given consumer. */
		public synchronized void iterate(Consumer<String> consumer) {
		public synchronized void iterate(LogConsumer<? super T> consumer) {
		LogIterator it = new LogIterator();
		while (it.hasNext()) {
		consumer.accept(it.next());
		}
		}

		/**
		* Iterates over the event log, passing each filter-matching log string to the given
		* consumer.
		*/
		public synchronized void iterate(String filter, Consumer<String> consumer) {
		LogIterator it = new LogIterator(filter);
		while (it.hasNext()) {
		consumer.accept(it.next());
		it.next();
		consumer.acceptLog(it.getTime(), it.getLog());
		}
		}

		// returns the index of the first element
		@GuardedBy("this")
		private int startIndex() {
		return wrapIndex(mLogEndIndex - mLogSize);
		}

		// returns the index after this one
		@GuardedBy("this")
		private int incrementIndex(int index) {
		if (index == -1) {
		return startIndex();
		@@ -238,69 +214,68 @@ public abstract class LocalEventLog {
		}

		// rolls over the given index if necessary
		@GuardedBy("this")
		private int wrapIndex(int index) {
		// java modulo will keep negative sign, we need to rollover
		return (index % mLog.length + mLog.length) % mLog.length;
		return (index % mEntries.length + mEntries.length) % mEntries.length;
		}

		private class LogIterator implements Iterator<String> {

		private final @Nullable String mFilter;

		private final long mSystemTimeDeltaMs;
		private class LogIterator {

		private long mCurrentRealtimeMs;
		private long mLogTime;
		private int mIndex;
		private int mCount;

		LogIterator() {
		this(null);
		}
		private long mCurrentTime;
		private T mCurrentLogEvent;

		LogIterator(@Nullable String filter) {
		mFilter = filter;
		mSystemTimeDeltaMs = System.currentTimeMillis() - SystemClock.elapsedRealtime();
		mCurrentRealtimeMs = mStartRealtimeMs;
		LogIterator() {
		synchronized (LocalEventLog.this) {
		mLogTime = mStartTime;
		mIndex = -1;
		mCount = -1;

		increment();
		}
		}

		@Override
		public boolean hasNext() {
		synchronized (LocalEventLog.this) {
		return mCount < mLogSize;
		}
		}

		public String next() {
		public void next() {
		synchronized (LocalEventLog.this) {
		if (!hasNext()) {
		throw new NoSuchElementException();
		}

		Log log = mLog[mIndex];
		long timeMs = mCurrentRealtimeMs + log.getTimeDeltaMs() + mSystemTimeDeltaMs;
		mCurrentTime = mLogTime + getTimeDelta(mEntries[mIndex]);
		mCurrentLogEvent = Objects.requireNonNull(mLogEvents[mIndex]);

		increment();
		}
		}

		return getTimePrefix(timeMs) + log.getLogString();
		public long getTime() {
		return mCurrentTime;
		}

		@Override
		public void remove() {
		throw new UnsupportedOperationException();
		public T getLog() {
		return mCurrentLogEvent;
		}

		private void increment() {
		long nextDeltaMs = mIndex == -1 ? 0 : mLog[mIndex].getTimeDeltaMs();
		@GuardedBy("LocalEventLog.this")
		private void increment(LogIterator this) {
		long nextDeltaMs = mIndex == -1 ? 0 : getTimeDelta(mEntries[mIndex]);
		do {
		mCurrentRealtimeMs += nextDeltaMs;
		mLogTime += nextDeltaMs;
		mIndex = incrementIndex(mIndex);
		if (++mCount < mLogSize) {
		nextDeltaMs = mLog[mIndex].getTimeDeltaMs();
		nextDeltaMs = getTimeDelta(mEntries[mIndex]);
		}
		} while (mCount < mLogSize && (mLog[mIndex].isFiller() \|\| (mFilter != null
		&& !mLog[mIndex].filter(mFilter))));
		} while (mCount < mLogSize && isFiller(mEntries[mIndex]));
		}
		}
		}

services/core/java/com/android/server/location/eventlog/LocationEventLog.java

+90 −143

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