More robust native library discovery in Mac OS X

Motivation:

Some JDK versions of Mac OS X generates a JNI dynamic library with '.jnilib' extension rather than with '.dynlib' extension.  However, System.mapLibraryName() always returns 'lib<name>.dynlib'. As a result, NativeLibraryLoader fails to load the native library whose extension is .jnilib.

Modification:

Try to find both '.jnilib' and '.dynlib' resources on OS X.

Result:

Dynamic libraries are loaded correctly in Mac OS X, and thus we can continue the OpenSslEngine work.

common/src/main/java/io/netty/util/internal/NativeLibraryLoader.java

@@ -24,6 +24,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.URL;
+import java.util.Locale;
 
 /**
  * Helper class to load JNI resources.
@@ -33,9 +34,13 @@ public final class NativeLibraryLoader {
 
     private static final InternalLogger logger = InternalLoggerFactory.getInstance(NativeLibraryLoader.class);
 
+    private static final String NATIVE_RESOURCE_HOME = "META-INF/native/";
+    private static final String OSNAME;
     private static final File WORKDIR;
 
     static {
+        OSNAME = SystemPropertyUtil.get("os.name", "").toLowerCase(Locale.US).replaceAll("[^a-z0-9]+", "");
+
         String workdir = SystemPropertyUtil.get("io.netty.native.workdir");
         if (workdir != null) {
             File f = new File(workdir);
@@ -52,25 +57,124 @@ public final class NativeLibraryLoader {
             }
 
             WORKDIR = f;
-            logger.debug("-Dio.netty.netty.workdir: {}", WORKDIR);
+            logger.debug("-Dio.netty.netty.workdir: " + WORKDIR);
         } else {
-            WORKDIR = PlatformDependent.tmpdir();
-            logger.debug("-Dio.netty.netty.workdir: {} (io.netty.tmpdir)", WORKDIR);
+            WORKDIR = tmpdir();
+            logger.debug("-Dio.netty.netty.workdir: " + WORKDIR + " (io.netty.tmpdir)");
         }
     }
 
+    private static File tmpdir() {
+        File f;
+        try {
+            f = toDirectory(SystemPropertyUtil.get("io.netty.tmpdir"));
+            if (f != null) {
+                logger.debug("-Dio.netty.tmpdir: " + f);
+                return f;
+            }
+
+            f = toDirectory(SystemPropertyUtil.get("java.io.tmpdir"));
+            if (f != null) {
+                logger.debug("-Dio.netty.tmpdir: " + f + " (java.io.tmpdir)");
+                return f;
+            }
+
+            // This shouldn't happen, but just in case ..
+            if (isWindows()) {
+                f = toDirectory(System.getenv("TEMP"));
+                if (f != null) {
+                    logger.debug("-Dio.netty.tmpdir: " + f + " (%TEMP%)");
+                    return f;
+                }
+
+                String userprofile = System.getenv("USERPROFILE");
+                if (userprofile != null) {
+                    f = toDirectory(userprofile + "\\AppData\\Local\\Temp");
+                    if (f != null) {
+                        logger.debug("-Dio.netty.tmpdir: " + f + " (%USERPROFILE%\\AppData\\Local\\Temp)");
+                        return f;
+                    }
+
+                    f = toDirectory(userprofile + "\\Local Settings\\Temp");
+                    if (f != null) {
+                        logger.debug("-Dio.netty.tmpdir: " + f + " (%USERPROFILE%\\Local Settings\\Temp)");
+                        return f;
+                    }
+                }
+            } else {
+                f = toDirectory(System.getenv("TMPDIR"));
+                if (f != null) {
+                    logger.debug("-Dio.netty.tmpdir: " + f + " ($TMPDIR)");
+                    return f;
+                }
+            }
+        } catch (Exception ignored) {
+            // Environment variable inaccessible
+        }
+
+        // Last resort.
+        if (isWindows()) {
+            f = new File("C:\\Windows\\Temp");
+        } else {
+            f = new File("/tmp");
+        }
+
+        logger.warn("Failed to get the temporary directory; falling back to: " + f);
+        return f;
+    }
+
+    @SuppressWarnings("ResultOfMethodCallIgnored")
+    private static File toDirectory(String path) {
+        if (path == null) {
+            return null;
+        }
+
+        File f = new File(path);
+        if (!f.exists()) {
+            f.mkdirs();
+        }
+
+        if (!f.isDirectory()) {
+            return null;
+        }
+
+        try {
+            return f.getAbsoluteFile();
+        } catch (Exception ignored) {
+            return f;
+        }
+    }
+
+    private static boolean isWindows() {
+        return OSNAME.startsWith("windows");
+    }
+
+    private static boolean isOSX() {
+        return OSNAME.startsWith("macosx") || OSNAME.startsWith("osx");
+    }
+
     /**
      * Load the given library with the specified {@link java.lang.ClassLoader}
      */
     public static void load(String name, ClassLoader loader) {
         String libname = System.mapLibraryName(name);
-        String path = "META-INF/native/" + libname;
+        String path = NATIVE_RESOURCE_HOME + libname;
 
         URL url = loader.getResource(path);
+        if (url == null && isOSX()) {
+            if (path.endsWith(".jnilib")) {
+                url = loader.getResource(NATIVE_RESOURCE_HOME + "lib" + name + ".dynlib");
+            } else {
+                url = loader.getResource(NATIVE_RESOURCE_HOME + "lib" + name + ".jnilib");
+            }
+        }
+
         if (url == null) {
             // Fall back to normal loading of JNI stuff
             System.loadLibrary(name);
-        } else {
+            return;
+        }
+
         int index = libname.lastIndexOf('.');
         String prefix = libname.substring(0, index);
         String suffix = libname.substring(index, libname.length());
@@ -123,7 +227,6 @@ public final class NativeLibraryLoader {
             }
         }
     }
-    }
 
     private NativeLibraryLoader() {
         // Utility