From eb7f751ba519cbcab47d640cd18757f09d077b55 Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Fri, 9 Sep 2016 11:16:25 +0200
Subject: [PATCH] Log less confusing message when try to load native library

Motivation:

At the moment we log very confusing messages when trying to load a native library which kind of suggest that the whole loading process failed even if just one mechanism failed and the library could be loaded at the end.

Modifications:

Make the mesage less confusing and also log a successful load of the native library.

Result:

Less confusing logs.
---
 .../util/internal/NativeLibraryLoader.java    | 31 ++++++++++++++-----
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/common/src/main/java/io/netty/util/internal/NativeLibraryLoader.java b/common/src/main/java/io/netty/util/internal/NativeLibraryLoader.java
index b8757b5b29..60859bab80 100644
--- a/common/src/main/java/io/netty/util/internal/NativeLibraryLoader.java
+++ b/common/src/main/java/io/netty/util/internal/NativeLibraryLoader.java
@@ -164,9 +164,10 @@ public final class NativeLibraryLoader {
         for (String name : names) {
             try {
                 load(name, loader);
+                logger.debug("Successfully loaded the library: {}", name);
                 return;
             } catch (Throwable t) {
-                logger.debug("Unable to load the library: " + name + '.', t);
+                logger.debug("Unable to load the library '{}', trying next name...", name, t);
             }
         }
         throw new IllegalArgumentException("Failed to load any of the given libraries: "
@@ -245,14 +246,18 @@ public final class NativeLibraryLoader {
             // Make sure the helper is belong to the target ClassLoader.
             final Class<?> newHelper = tryToLoadClass(loader, NativeLibraryUtil.class);
             loadLibraryByHelper(newHelper, name, absolute);
-        } catch (Exception e) { // Should by pass the UnsatisfiedLinkError here!
-            logger.debug("Unable to load the library: " + name + '.', e);
-            NativeLibraryUtil.loadLibrary(name, absolute);  // Fallback to local helper class.
+            return;
+        } catch (UnsatisfiedLinkError e) { // Should by pass the UnsatisfiedLinkError here!
+            logger.debug("Unable to load the library '{}', trying other loading mechanism.", name, e);
+        } catch (Exception e) {
+            logger.debug("Unable to load the library '{}', trying other loading mechanism.", name, e);
         }
+        NativeLibraryUtil.loadLibrary(name, absolute);  // Fallback to local helper class.
     }
 
-    private static void loadLibraryByHelper(final Class<?> helper, final String name, final boolean absolute) {
-        AccessController.doPrivileged(new PrivilegedAction<Object>() {
+    private static void loadLibraryByHelper(final Class<?> helper, final String name, final boolean absolute)
+            throws UnsatisfiedLinkError {
+        Object ret = AccessController.doPrivileged(new PrivilegedAction<Object>() {
             @Override
             public Object run() {
                 try {
@@ -263,10 +268,22 @@ public final class NativeLibraryLoader {
                     method.setAccessible(true);
                     return method.invoke(null, name, absolute);
                 } catch (Exception e) {
-                    throw new IllegalStateException("Load library failed!", e);
+                    return e;
                 }
             }
         });
+        if (ret instanceof Throwable) {
+            Throwable error = (Throwable) ret;
+            Throwable cause = error.getCause();
+            if (cause != null) {
+                if (cause instanceof UnsatisfiedLinkError) {
+                    throw (UnsatisfiedLinkError) cause;
+                } else {
+                    throw new UnsatisfiedLinkError(cause.getMessage());
+                }
+            }
+            throw new UnsatisfiedLinkError(error.getMessage());
+        }
     }
 
     /**