* Move native Loader methods to Helper class to avoid deadlocks (issue #737)

Author: saudet

CHANGELOG.md

@@ -1,4 +1,5 @@
 
+ * Move native `Loader` methods to `Helper` class to avoid deadlocks ([issue #737](https://github.com/bytedeco/javacpp/issues/737))
  * Fix `Parser` failing to pick up `Info` for constructors with template arguments ([pull #739](https://github.com/bytedeco/javacpp/pull/739))
  * Fix `MoveAdapter` and `UniquePtrAdapter` causing double free on function calls ([pull #738](https://github.com/bytedeco/javacpp/pull/738))
  * Fix `Parser` handling of `template` specialization and their `friend` declarations ([pull #733](https://github.com/bytedeco/javacpp/pull/733))

src/main/java/org/bytedeco/javacpp/Loader.java

@@ -1968,16 +1968,6 @@ public static String createLibraryLink(String filename, ClassProperties properti
     static WeakHashMap<Class<? extends Pointer>,HashMap<String,Integer>> memberOffsets =
             new WeakHashMap<Class<? extends Pointer>,HashMap<String,Integer>>();
 
-    static {
-        try {
-            Loader.load();
-        } catch (Throwable t) {
-            if (logger.isDebugEnabled()) {
-                logger.debug("Could not load Loader: " + t);
-            }
-        }
-    }
-
     /**
      * Called by native libraries to put {@code offsetof()} and {@code sizeof()} values in {@link #memberOffsets}.
      * Tries to load the Class object for typeName using the {@link ClassLoader} of the Loader.
@@ -2044,37 +2034,75 @@ public static int sizeof(Class<? extends Pointer> type) {
         return offsetof(type, "sizeof");
     }
 
+    public static class Helper {
+        static {
+            try {
+                Loader.load();
+            } catch (Throwable t) {
+                if (logger.isDebugEnabled()) {
+                    logger.debug("Could not load Loader.Helper: " + t);
+                }
+            }
+        }
+
+        /** Returns the number of processors configured according to the operating system, or 0 if unknown.
+         * This value can be greater than {@link Runtime#availableProcessors()} and {@link #totalCores()}. */
+        @Name("JavaCPP_totalProcessors") public static native int totalProcessors();
+
+        /** Returns the number of CPU cores usable according to the operating system, or 0 if unknown.
+         * For SMT-capable systems, this value may be less than {@link #totalProcessors()}. */
+        @Name("JavaCPP_totalCores") public static native int totalCores();
+
+        /** Returns the number of CPU chips installed according to the operating system, or 0 if unknown.
+         * For multi-core processors, this value may be less than {@link #totalCores()}. */
+        @Name("JavaCPP_totalChips") public static native int totalChips();
+
+        /** Returns the address found under the given name in the "dynamic symbol tables" (Linux, Mac OS X, etc)
+         * or the "export tables" (Windows) of all libraries loaded, or null if not found. */
+        @Name("JavaCPP_addressof") public static native Pointer addressof(String symbol);
+
+        /** Loads all symbols from a library globally, that is {@code dlopen(filename, RTLD_LAZY | RTLD_GLOBAL)},
+         * or simply by default with {@code LoadLibrary(filename)} on Windows. If the library name passed to
+         * one of the other load functions in this class ends with "!", this function will get called on them. */
+        @Name("JavaCPP_loadGlobal") @Raw(withEnv = true) public static native void loadGlobal(String filename);
+
+        /** Returns the JavaVM JNI object, as required by some APIs for initialization. */
+        @Name("JavaCPP_getJavaVM") public static native @Cast("JavaVM*") Pointer getJavaVM();
+
+        /** Returns a JNI global reference stored in a Pointer for the given Object. */
+        @Name("JavaCPP_newGlobalRef") public static native @Cast("jobject") Pointer newGlobalRef(@Raw(withEnv = true) Object object);
+
+        /** Returns an Object from the JNI global reference stored in the Pointer. */
+        @Name("JavaCPP_accessGlobalRef") @Raw(withEnv = true) public static native Object accessGlobalRef(@Cast("jobject") Pointer globalRef);
+
+        /** Deletes the JNI global reference stored in the Pointer. */
+        @Name("JavaCPP_deleteGlobalRef") @Raw(withEnv = true) public static native void deleteGlobalRef(@Cast("jobject") Pointer globalRef);
+    }
 
-    /** Returns the number of processors configured according to the operating system, or 0 if unknown.
-     * This value can be greater than {@link Runtime#availableProcessors()} and {@link #totalCores()}. */
-    @Name("JavaCPP_totalProcessors") public static native int totalProcessors();
+    /** Returns {@link Helper#totalProcessors()}. */
+    public static int totalProcessors() { return Helper.totalProcessors(); }
 
-    /** Returns the number of CPU cores usable according to the operating system, or 0 if unknown.
-     * For SMT-capable systems, this value may be less than {@link #totalProcessors()}. */
-    @Name("JavaCPP_totalCores") public static native int totalCores();
+    /** Returns {@link Helper#totalCores()}. */
+    public static int totalCores() { return Helper.totalCores(); }
 
-    /** Returns the number of CPU chips installed according to the operating system, or 0 if unknown.
-     * For multi-core processors, this value may be less than {@link #totalCores()}. */
-    @Name("JavaCPP_totalChips") public static native int totalChips();
+    /** Returns {@link Helper#totalChips()}. */
+    public static int totalChips() { return Helper.totalChips(); }
 
-    /** Returns the address found under the given name in the "dynamic symbol tables" (Linux, Mac OS X, etc)
-     * or the "export tables" (Windows) of all libraries loaded, or null if not found. */
-    @Name("JavaCPP_addressof") public static native Pointer addressof(String symbol);
+    /** Returns {@link Helper#addressof(String)}. */
+    public static Pointer addressof(String symbol) { return Helper.addressof(symbol); }
 
-    /** Loads all symbols from a library globally, that is {@code dlopen(filename, RTLD_LAZY | RTLD_GLOBAL)},
-     * or simply by default with {@code LoadLibrary(filename)} on Windows. If the library name passed to
-     * one of the other load functions in this class ends with "!", this function will get called on them. */
-    @Name("JavaCPP_loadGlobal") @Raw(withEnv = true) public static native void loadGlobal(String filename);
+    /** Calls {@link Helper#loadGlobal(String)}. */
+    public static void loadGlobal(String filename) { Helper.loadGlobal(filename); }
 
-    /** Returns the JavaVM JNI object, as required by some APIs for initialization. */
-    @Name("JavaCPP_getJavaVM") public static native @Cast("JavaVM*") Pointer getJavaVM();
+    /** Returns {@link Helper#getJavaVM()}. */
+    public static Pointer getJavaVM() { return Helper.getJavaVM(); }
 
-    /** Returns a JNI global reference stored in a Pointer for the given Object. */
-    @Name("JavaCPP_newGlobalRef") public static native @Cast("jobject") Pointer newGlobalRef(@Raw(withEnv = true) Object object);
+    /** Returns {@link Helper#newGlobalRef(Object)}. */
+    public static Pointer newGlobalRef(Object object) { return Helper.newGlobalRef(object); }
 
-    /** Returns an Object from the JNI global reference stored in the Pointer. */
-    @Name("JavaCPP_accessGlobalRef") @Raw(withEnv = true) public static native Object accessGlobalRef(@Cast("jobject") Pointer globalRef);
+    /** Returns {@link Helper#accessGlobalRef(Pointer)}. */
+    public static Object accessGlobalRef(Pointer globalRef) { return Helper.accessGlobalRef(globalRef); }
 
-    /** Deletes the JNI global reference stored in the Pointer. */
-    @Name("JavaCPP_deleteGlobalRef") @Raw(withEnv = true) public static native void deleteGlobalRef(@Cast("jobject") Pointer globalRef);
+    /** Calls {@link Helper#deleteGlobalRef(Pointer)}. */
+    public static void deleteGlobalRef(Pointer globalRef) { Helper.deleteGlobalRef(globalRef); }
 }

src/main/java/org/bytedeco/javacpp/tools/Generator.java

@@ -154,7 +154,7 @@ static enum IntEnum { INT; int value; }
     static enum LongEnum { LONG; long value; }
     static final String JNI_VERSION = "JNI_VERSION_1_6";
     static final List<Class> baseClasses = Arrays.asList(new Class[] {
-            Loader.class,
+            Loader.Helper.class,
             Pointer.class,
             //FunctionPointer.class,
             BytePointer.class,
@@ -2065,6 +2065,7 @@ boolean methods(Class<?> cls) {
         Set<String> memberList = members.get(cls);
         if (!cls.isAnnotationPresent(Opaque.class) && cls != Loader.class
                 && !FunctionPointer.class.isAssignableFrom(cls)
+                && cls.getEnclosingClass() != Loader.class
                 && cls.getEnclosingClass() != Pointer.class) {
             if (memberList == null) {
                 members.put(cls, memberList = new LinkedHashSet<String>());