Router: Store router ident and hash at startup

so ctx.routerHash() can be lockless

router/java/src/net/i2p/router/Router.java

@@ -43,6 +43,7 @@ import net.i2p.data.SigningPrivateKey;
 import net.i2p.data.SigningPublicKey;
 import net.i2p.data.i2np.GarlicMessage;
 import net.i2p.data.router.RouterAddress;
+import net.i2p.data.router.RouterIdentity;
 import net.i2p.data.router.RouterInfo;
 import net.i2p.router.CommSystemFacade.Status;
 import net.i2p.router.crypto.FamilyKeyCrypto;
@@ -94,6 +95,8 @@ public class Router implements RouterClock.ClockShiftListener {
     private String _configFilename;
     private RouterInfo _routerInfo;
     private final ReentrantReadWriteLock _routerInfoLock = new ReentrantReadWriteLock(false);
+    private RouterIdentity _routerIdent;
+    private Hash _routerHash;
     /** not for external use */
     public final Object routerInfoFileLock = new Object();
     private final Object _configFileLock = new Object();
@@ -583,6 +586,26 @@ public class Router implements RouterClock.ClockShiftListener {
         }
     }
 
+    /**
+     *  Our current router identity.
+     *  Warning, may be null if called very early.
+     *  Lockless.
+     *  @since 0.9.67
+     */
+    public RouterIdentity getRouterIdentity() {
+        return _routerIdent;
+    }
+
+    /**
+     *  Our current router hash.
+     *  Warning, may be null if called very early.
+     *  Lockless.
+     *  @since 0.9.67
+     */
+    public Hash getRouterHash() {
+        return _routerHash;
+    }
+
     /**
      *  Caller must ensure info is valid - no validation done here.
      *  Not for external use.
@@ -592,6 +615,12 @@ public class Router implements RouterClock.ClockShiftListener {
      */
     public void setRouterInfo(RouterInfo info) { 
         _routerInfoLock.writeLock().lock();
+        if (!info.getIdentity().equals(_routerIdent)) {
+            if (_routerIdent != null)  // shouldn't happen
+                _log.log(Log.CRIT, "Changing router ident while running");
+            _routerIdent = info.getIdentity();
+            _routerHash = _routerIdent.calculateHash();
+        }
         try {
             _routerInfo = info; 
         } finally {

router/java/src/net/i2p/router/RouterContext.java

@@ -316,17 +316,12 @@ public class RouterContext extends I2PAppContext {
      *  Convenience method for getting the router hash.
      *  Equivalent to context.router().getRouterInfo().getIdentity().getHash()
      *
-     *  Warning - risk of deadlock - do not call while holding locks
-     *
      *  @return may be null if called very early
      */
     public Hash routerHash() {
         if (_router == null)
             return null;
-        RouterInfo ri = _router.getRouterInfo();
-        if (ri == null)
-            return null;
-        return ri.getIdentity().getHash();
+        return _router.getRouterHash();
     }
 
     /**