2006-09-26 Complication

* Subclass from Clock a RouterClock which can access router transports,
      with the goal of developing it to second-guess NTP results
    * Make transports report clock skew in seconds
    * Adjust renderStatusHTML() methods accordingly
    * Show average for NTCP clock skews too
    * Give transports a getClockSkews() method to report clock skews
    * Give transport manager a getClockSkews() method to aggregate results
    * Give comm system facade a getMedianPeerClockSkew() method which RouterClock calls
      (to observe results, add "net.i2p.router.transport.CommSystemFacadeImpl=WARN" to
logging)
    * Extra explicitness in NTCP classes to denote unit of time.
    * Fix some places in NTCPConnection where milliseconds and seconds were confused

core/java/src/net/i2p/I2PAppContext.java

@@ -68,7 +68,7 @@ public class I2PAppContext {
     private LogManager _logManager;
     private HMACGenerator _hmac;
     private SHA256Generator _sha;
-    private Clock _clock;
+    protected Clock _clock; // overridden in RouterContext
     private DSAEngine _dsa;
     private RoutingKeyGenerator _routingKeyGenerator;
     private RandomSource _random;
@@ -83,7 +83,7 @@ public class I2PAppContext {
     private volatile boolean _logManagerInitialized;
     private volatile boolean _hmacInitialized;
     private volatile boolean _shaInitialized;
-    private volatile boolean _clockInitialized;
+    protected volatile boolean _clockInitialized; // used in RouterContext
     private volatile boolean _dsaInitialized;
     private volatile boolean _routingKeyGeneratorInitialized;
     private volatile boolean _randomInitialized;
@@ -411,11 +411,11 @@ public class I2PAppContext {
      * enable simulators to play with clock skew among different instances.
      *
      */
-    public Clock clock() { 
+    public Clock clock() { // overridden in RouterContext
         if (!_clockInitialized) initializeClock();
         return _clock;
     }
-    private void initializeClock() {
+    protected void initializeClock() { // overridden in RouterContext
         synchronized (this) {
             if (_clock == null)
                 _clock = new Clock(this);

core/java/src/net/i2p/util/Clock.java

@@ -13,12 +13,16 @@ import net.i2p.time.Timestamper;
  * between the local computer's current time and the time as known by some reference
  * (such as an NTP synchronized clock).
  *
+ * Protected members are used in the subclass RouterClock,
+ * which has access to a router's transports (particularly peer clock skews)
+ * to second-guess the sanity of clock adjustments.
+ *
  */
 public class Clock implements Timestamper.UpdateListener {
-    private I2PAppContext _context;
+    protected I2PAppContext _context;
     private Timestamper _timestamper;
-    private long _startedOn;
-    private boolean _statCreated;
+    protected long _startedOn;
+    protected boolean _statCreated;
     
     public Clock(I2PAppContext context) {
         _context = context;
@@ -36,10 +40,10 @@ public class Clock implements Timestamper.UpdateListener {
     public Timestamper getTimestamper() { return _timestamper; }
     
     /** we fetch it on demand to avoid circular dependencies (logging uses the clock) */
-    private Log getLog() { return _context.logManager().getLog(Clock.class); }
+    protected Log getLog() { return _context.logManager().getLog(Clock.class); }
     
-    private volatile long _offset;
-    private boolean _alreadyChanged;
+    protected volatile long _offset;
+    protected boolean _alreadyChanged;
     private Set _listeners;
 
     /** if the clock is skewed by 3+ days, fuck 'em */
@@ -132,7 +136,7 @@ public class Clock implements Timestamper.UpdateListener {
         }
     }
 
-    private void fireOffsetChanged(long delta) {
+    protected void fireOffsetChanged(long delta) {
         synchronized (_listeners) {
             for (Iterator iter = _listeners.iterator(); iter.hasNext();) {
                 ClockUpdateListener lsnr = (ClockUpdateListener) iter.next();