Re: Remove exception from sun.rmi.runtime.Log#getSource()

[Mandy Chung]

This patch looks okay to me.

Mandy

On 8/23/19 8:44 AM, Roger Riggs wrote:

Hi Philippe,

The change looks good, I'll run it through our tests and push if its all ok.

(Pending anyone else's comments.)

On 8/23/19 10:38 AM, Philippe Marschall wrote:

On 22.08.19 19:56, Mandy Chung wrote:

Hi Philippe,

This is a good use of StackWalker.   getSource can simply return
StackFrame and avoid the creation of String[].

Updated webrev [1] and inline diff at the end.

Something I noted is that we could replace
sun.rmi.runtime.Log.LogStreamLog.unqualifiedName(String) with
Class#getSimpleName() which is cached since JDK-8187123. That would
remove an additional bit of allocation. However only in the pre-1.4
logging case, which I assume is uncommon. In addition that would require
us to create a StackWalker with Option#RETAIN_CLASS_REFERENCE. If we do
not want to do this in the jul case we would have to create a LogFactory
specific #getSource implementation with a different StackWalker. I am
not sure this is worth it.

Stuart will give you better guidance related to RMI testing.

I see that test/jdk/sun/rmi/runtime/Log has a few RMI logging tests.
RMI tests are in tier3.  You can run jdk_rmi test group to verify
this patch.

I am new to this, I did

make run-test TEST=jdk_rmi

and all tests passed.

That's a start, running the complete suite of tests may catch something else or another dependency outside of the specific rmi tests.

I notice that pre-1.4 RMI logging support.  I wonder if this is
time to remove it.

I would love to do this but I would assume that requires at least a
different issue and probably a change note that the property and feature
are gone. I assume deprecating java.rmi.server.LogStream for removal is
not an option.

Right, that's a separate issue and takes work and process to remove.

I'll be away from a keyboard for a week so I won't be able to answer.

ok, Enjoy

Thanks, Roger

--- old/src/java.rmi/share/classes/sun/rmi/runtime/Log.java 2019-08-23
15:43:28.452810308 +0200
+++ new/src/java.rmi/share/classes/sun/rmi/runtime/Log.java 2019-08-23
15:43:28.320811517 +0200
@@ -28,8 +28,10 @@
 import java.io.ByteArrayOutputStream;
 import java.io.PrintStream;
 import java.io.OutputStream;
+import java.lang.StackWalker.StackFrame;
 import java.rmi.server.LogStream;
 import java.security.PrivilegedAction;
+import java.util.Set;
 import java.util.logging.Handler;
 import java.util.logging.SimpleFormatter;
 import java.util.logging.Level;
@@ -62,6 +64,8 @@
     public static final Level BRIEF = Level.FINE;
     public static final Level VERBOSE = Level.FINER;

+    private static final StackWalker WALKER =
StackWalker.getInstance(Set.of(), 4);
+
     /* selects log implementation */
     private static final LogFactory logFactory;
     static {
@@ -217,16 +221,16 @@

         public void log(Level level, String message) {
             if (isLoggable(level)) {
-                String[] source = getSource();
-                logger.logp(level, source[0], source[1],
+                StackFrame sourceFrame = getSource();
+                logger.logp(level, sourceFrame.getClassName(),
sourceFrame.getMethodName(),
                            Thread.currentThread().getName() + ": " +
message);
             }
         }

         public void log(Level level, String message, Throwable thrown) {

             if (isLoggable(level)) {
-                String[] source = getSource();
-                logger.logp(level, source[0], source[1],
+                StackFrame sourceFrame = getSource();
+                logger.logp(level, sourceFrame.getClassName(),
sourceFrame.getMethodName(),
                     Thread.currentThread().getName() + ": " +
                            message, thrown);
             }
@@ -390,9 +394,9 @@

         public void log(Level messageLevel, String message) {
             if (isLoggable(messageLevel)) {
-                String[] source = getSource();
-                stream.println(unqualifiedName(source[0]) +
-                               "." + source[1] + ": " + message);
+                StackFrame sourceFrame = getSource();
+
stream.println(unqualifiedName(sourceFrame.getClassName()) +
+                               "." + sourceFrame.getMethodName() + ": "
+ message);
             }
         }

@@ -403,9 +407,9 @@
                  * RemoteServer.getLog
                  */
                 synchronized (stream) {
-                    String[] source = getSource();
-                    stream.println(unqualifiedName(source[0]) + "." +
-                                   source[1] + ": " + message);
+                    StackFrame sourceFrame = getSource();
+
stream.println(unqualifiedName(sourceFrame.getClassName()) + "." +
+                                    sourceFrame.getMethodName() + ": "
+ message);
                     thrown.printStackTrace(stream);
                 }
             }
@@ -441,13 +445,12 @@
     }

     /**
-     * Obtain class and method names of code calling a log method.
+     * Obtain stack frame of code calling a log method.
      */
-    private static String[] getSource() {
-        StackTraceElement[] trace = (new Exception()).getStackTrace();
-        return new String[] {
-            trace[3].getClassName(),
-            trace[3].getMethodName()
-        };
+    private static StackFrame getSource() {
+        return WALKER.walk(s -> s
+                                 .skip(3)
+                                 .findFirst()
+      �