Adds support for a custom SymbolProvider in NativeLibrary & Library

CHANGES.md

@@ -12,6 +12,7 @@ Features
 * [#1471](https://github.com/java-native-access/jna/pull/1471): Add `c.s.j.p.win32.Advapi32Util#isCurrentProcessElevated` and associated Types - [@dbwiddis](https://github.com/dbwiddis).
 * [#1474](https://github.com/java-native-access/jna/pull/1474): Add `c.s.j.p.win32.WbemCli#IWbemClassObject.IWbemQualifierSet`, `IWbemServices.GetObject`, `IWbemContext.SetValue` and associated methods - [@rchateauneu](https://github.com/rchateauneu).
 * [#1482](https://github.com/java-native-access/jna/pull/1482): Add multilingual support of `Kernel32Util.formatMessage` - [@overpathz](https://github.com/overpathz).
+* [#1490](https://github.com/java-native-access/jna/pull/1490): Adds support for a custom `SymbolProvider` in `NativeLibrary` & `Library` - [@soywiz](https://github.com/soywiz).
 
 Bug Fixes
 ---------

src/com/sun/jna/Library.java

@@ -114,6 +114,11 @@ public interface Library {
      */
     String OPTION_CLASSLOADER = "classloader";
 
+    /**
+     * Supports a custom symbol provider for the NativeLibrary (see {@link SymbolProvider})
+     */
+    String OPTION_SYMBOL_PROVIDER = "symbol-provider";
+
     static class Handler implements InvocationHandler {
 
         static final Method OBJECT_TOSTRING;

src/com/sun/jna/NativeLibrary.java

@@ -87,13 +87,20 @@
 public class NativeLibrary implements Closeable {
 
     private static final Logger LOG = Logger.getLogger(NativeLibrary.class.getName());
-    private final static Level DEBUG_LOAD_LEVEL = DEBUG_LOAD ? Level.INFO : Level.FINE;
+    private static final Level DEBUG_LOAD_LEVEL = DEBUG_LOAD ? Level.INFO : Level.FINE;
+    private static final SymbolProvider NATIVE_SYMBOL_PROVIDER = new SymbolProvider() {
+        @Override
+        public long getSymbolAddress(long handle, String name, SymbolProvider parent) {
+            return Native.findSymbol(handle, name);
+        }
+    };
 
     private Cleaner.Cleanable cleanable;
     private long handle;
     private final String libraryName;
     private final String libraryPath;
     private final Map<String, Function> functions = new HashMap<String, Function>();
+    private final SymbolProvider symbolProvider;
     final int callFlags;
     private String encoding;
     final Map<String, ?> options;
@@ -123,6 +130,13 @@ private NativeLibrary(String libraryName, String libraryPath, long handle, Map<S
         this.callFlags = callingConvention;
         this.options = options;
         this.encoding = (String)options.get(Library.OPTION_STRING_ENCODING);
+        SymbolProvider optionSymbolProvider = (SymbolProvider)options.get(Library.OPTION_SYMBOL_PROVIDER);
+        if (optionSymbolProvider == null) {
+            this.symbolProvider = NATIVE_SYMBOL_PROVIDER;
+        } else {
+            this.symbolProvider = optionSymbolProvider;
+        }
+
         if (this.encoding == null) {
             this.encoding = Native.getDefaultStringEncoding();
         }
@@ -636,7 +650,7 @@ long getSymbolAddress(String name) {
         if (handle == 0) {
             throw new UnsatisfiedLinkError("Library has been unloaded");
         }
-        return Native.findSymbol(handle, name);
+        return this.symbolProvider.getSymbolAddress(handle, name, NATIVE_SYMBOL_PROVIDER);
     }
 
     @Override

src/com/sun/jna/SymbolProvider.java

@@ -0,0 +1,43 @@
+/* Copyright (c) 2022 Carlos Ballesteros, All Rights Reserved
+ *
+ * The contents of this file is dual-licensed under 2
+ * alternative Open Source/Free licenses: LGPL 2.1 or later and
+ * Apache License 2.0. (starting with JNA version 4.0.0).
+ *
+ * You can freely decide which license you want to apply to
+ * the project.
+ *
+ * You may obtain a copy of the LGPL License at:
+ *
+ * http://www.gnu.org/licenses/licenses.html
+ *
+ * A copy is also included in the downloadable source code package
+ * containing JNA, in file "LGPL2.1".
+ *
+ * You may obtain a copy of the Apache License at:
+ *
+ * http://www.apache.org/licenses/
+ *
+ * A copy is also included in the downloadable source code package
+ * containing JNA, in file "AL2.0".
+ */
+package com.sun.jna;
+
+/**
+ * Interface to define a custom symbol provider.
+ *
+ * This can be used for method hooking, or special
+ * classes like direct mapping the Win32 OpenGL.
+ */
+public interface SymbolProvider {
+    /**
+     * Gets the address of a symbol by its name and the handle of the library.
+     *
+     * @param handle Handle of the original library
+     * @param name Name of the symbol to load
+     * @param parent Parent symbol provider
+     *
+     * @return Address of the symbol, typically a function.
+     */
+    long getSymbolAddress(long handle, String name, SymbolProvider parent);
+}

test/com/sun/jna/NativeCustomSymbolProviderTest.java

@@ -0,0 +1,104 @@
+/* Copyright (c) 2022 Carlos Ballesteros, All Rights Reserved
+ *
+ * The contents of this file is dual-licensed under 2
+ * alternative Open Source/Free licenses: LGPL 2.1 or later and
+ * Apache License 2.0. (starting with JNA version 4.0.0).
+ *
+ * You can freely decide which license you want to apply to
+ * the project.
+ *
+ * You may obtain a copy of the LGPL License at:
+ *
+ * http://www.gnu.org/licenses/licenses.html
+ *
+ * A copy is also included in the downloadable source code package
+ * containing JNA, in file "LGPL2.1".
+ *
+ * You may obtain a copy of the Apache License at:
+ *
+ * http://www.apache.org/licenses/
+ *
+ * A copy is also included in the downloadable source code package
+ * containing JNA, in file "AL2.0".
+ */
+package com.sun.jna;
+
+import junit.framework.TestCase;
+
+import java.util.Collections;
+
+public class NativeCustomSymbolProviderTest extends TestCase implements Paths {
+    public static void main(java.lang.String[] argList) {
+        junit.textui.TestRunner.run(NativeCustomSymbolProviderTest.class);
+    }
+
+    interface MathInterfaceWithSymbolProvider extends Library {
+
+        double sin(double x);
+        double cos(double x);
+
+    }
+
+    static class MathLibraryWithSymbolProvider {
+
+        public static native double sin(double x);
+        public static native double cos(double x);
+
+        static {
+            Native.register(MathLibraryWithSymbolProvider.class, NativeLibrary.getInstance(Platform.MATH_LIBRARY_NAME, Collections.singletonMap(
+                    Library.OPTION_SYMBOL_PROVIDER,
+                    new SymbolProvider() {
+                        @Override
+                        public long getSymbolAddress(long handle, String name, SymbolProvider parent) {
+                            if (name.equals("sin")) {
+                                return parent.getSymbolAddress(handle, "cos", null);
+                            } else {
+                                return parent.getSymbolAddress(handle, "sin", null);
+                            }
+                        }
+                    }
+            )));
+        }
+    }
+
+    MathInterfaceWithSymbolProvider lib;
+    MathInterfaceWithSymbolProvider libCustom;
+
+    @Override
+    protected void setUp() {
+        lib = Native.load(Platform.MATH_LIBRARY_NAME, MathInterfaceWithSymbolProvider.class);
+        libCustom = Native.load(
+                Platform.MATH_LIBRARY_NAME,
+                MathInterfaceWithSymbolProvider.class, Collections.singletonMap(
+                        Library.OPTION_SYMBOL_PROVIDER,
+                        new SymbolProvider() {
+                            @Override
+                            public long getSymbolAddress(long handle, String name, SymbolProvider parent) {
+                                if (name.equals("sin")) {
+                                    return parent.getSymbolAddress(handle, "cos", null);
+                                } else {
+                                    return parent.getSymbolAddress(handle, "sin", null);
+                                }
+                            }
+                        }
+                )
+        );
+    }
+
+    @Override
+    protected void tearDown() {
+        lib = null;
+        libCustom = null;
+    }
+
+
+    public void testDirectMappingSymbolProvider() {
+        assertEquals(lib.cos(0.0), MathLibraryWithSymbolProvider.sin(0.0));
+        assertEquals(lib.sin(0.0), MathLibraryWithSymbolProvider.cos(0.0));
+    }
+
+    public void testInterfaceCustomSymbolProvider() {
+        assertEquals(lib.cos(0.0), libCustom.sin(0.0));
+        assertEquals(lib.sin(0.0), libCustom.cos(0.0));
+    }
+}