Implement equals, hashCode and toString for Objective-C objects

Interop/Runtime/src/native/kotlin/kotlinx/cinterop/ObjectiveCImpl.kt

@@ -23,9 +23,9 @@ interface ObjCClass : ObjCObject
 typealias ObjCObjectMeta = ObjCClass
 
 abstract class ObjCObjectBase protected constructor() : ObjCObject {
-    final override fun equals(other: Any?): Boolean = TODO()
-    final override fun hashCode(): Int = TODO()
-    final override fun toString(): String = TODO()
+    final override fun equals(other: Any?): Boolean = this.uncheckedCast<ObjCPointerHolder>().equals(other)
+    final override fun hashCode(): Int = ObjCHashCode(this.rawPtr)
+    final override fun toString(): String = ObjCToString(this.rawPtr)
 }
 
 abstract class ObjCObjectBaseMeta protected constructor() : ObjCObjectBase(), ObjCObjectMeta {}
@@ -42,9 +42,11 @@ class ObjCPointerHolder(inline val rawPtr: NativePtr) {
         objc_retain(rawPtr)
     }
 
-    final override fun equals(other: Any?): Boolean = TODO()
-    final override fun hashCode(): Int = TODO()
-    final override fun toString(): String = TODO()
+    final override fun equals(other: Any?): Boolean =
+            (other is ObjCPointerHolder) && ObjCEquals(this.rawPtr, other.rawPtr)
+
+    final override fun hashCode(): Int = ObjCHashCode(this.rawPtr)
+    final override fun toString(): String = ObjCToString(this.rawPtr)
 }
 
 @konan.internal.Intrinsic
@@ -146,12 +148,22 @@ private external fun <T : ObjCObject> getObjCClass(): NativePtr
 
 // Konan runtme:
 
-@SymbolName("CreateNSStringFromKString")
+@SymbolName("Kotlin_Interop_CreateNSStringFromKString")
 external fun CreateNSStringFromKString(str: String?): NativePtr
 
-@SymbolName("CreateKStringFromNSString")
+@SymbolName("Kotlin_Interop_CreateKStringFromNSString")
 external fun CreateKStringFromNSString(ptr: NativePtr): String?
 
+@SymbolName("Kotlin_Interop_ObjCToString")
+private external fun ObjCToString(ptr: NativePtr): String
+
+@SymbolName("Kotlin_Interop_ObjCHashCode")
+private external fun ObjCHashCode(ptr: NativePtr): Int
+
+@SymbolName("Kotlin_Interop_ObjCEquals")
+private external fun ObjCEquals(ptr: NativePtr, otherPtr: NativePtr): Boolean
+
+
 // Objective-C runtime:
 
 @SymbolName("objc_retainAutoreleaseReturnValue")

backend.native/tests/build.gradle

@@ -2101,7 +2101,8 @@ if (isMac()) {
 
     task interop_objc_smoke(type: RunInteropKonanTest) {
         disabled = (project.testTarget == 'wasm32') // No interop for wasm yet.
-        goldValue = "Hello, World!\nKotlin says: Hello, everybody!\nHello from Kotlin\n2, 1\nDeallocated\nDeallocated\n"
+        goldValue = "Hello, World!\nKotlin says: Hello, everybody!\nHello from Kotlin\n2, 1\n" +
+                "true\ntrue\nDeallocated\nDeallocated\n"
 
         source = "interop/objc/smoke.kt"
         interop = 'objcSmoke'

backend.native/tests/interop/objc/smoke.kt

@@ -23,6 +23,21 @@ fun run() {
     replacePairElements(pair, 1, 2)
     pair.swap()
     println("${pair.first}, ${pair.second}")
+
+    // equals and hashCode (virtually):
+    val map = mapOf(foo to pair, pair to foo)
+
+    // equals (directly):
+    if (!foo.equals(pair)) {
+        // toString (directly):
+        println(map[pair].toString() + map[foo].toString() == foo.description() + pair.description())
+    }
+
+    // hashCode (directly):
+    if (foo.hashCode() == foo.hash().toInt()) {
+        // toString (virtually):
+        println(map.keys.map { it.toString() }.min() == foo.description())
+    }
 }
 
 fun MutablePairProtocol.swap() {

runtime/src/main/cpp/ObjCInteropUtils.mm

@@ -44,7 +44,7 @@ namespace {
 
 extern "C" {
 
-NSString* CreateNSStringFromKString(const ArrayHeader* str) {
+NSString* Kotlin_Interop_CreateNSStringFromKString(const ArrayHeader* str) {
   if (str == nullptr) {
     return nullptr;
   }
@@ -58,7 +58,7 @@ NSString* CreateNSStringFromKString(const ArrayHeader* str) {
   return result;
 }
 
-OBJ_GETTER(CreateKStringFromNSString, NSString* str) {
+OBJ_GETTER(Kotlin_Interop_CreateKStringFromNSString, NSString* str) {
   if (str == nullptr) {
     RETURN_OBJ(nullptr);
   }
@@ -73,6 +73,18 @@ OBJ_GETTER(CreateKStringFromNSString, NSString* str) {
   RETURN_OBJ(result->obj());
 }
 
+OBJ_GETTER(Kotlin_Interop_ObjCToString, id <NSObject> ptr) {
+  RETURN_RESULT_OF(Kotlin_Interop_CreateKStringFromNSString, ptr.description);
+}
+
+KInt Kotlin_Interop_ObjCHashCode(id <NSObject> ptr) {
+  return (KInt) ptr.hash;
+}
+
+KBoolean Kotlin_Interop_ObjCEquals(id <NSObject> ptr, id otherPtr) {
+  return [ptr isEqual:otherPtr];
+}
+
 // Note: this body is used for init methods with signatures differing from this;
 // it is correct on arm64 and x86_64, because the body uses only the first two arguments which are fixed,
 // and returns pointers.
@@ -97,16 +109,31 @@ id MissingInitImp(id self, SEL _cmd) {
 
 extern "C" {
 
-void* CreateNSStringFromKString(const ArrayHeader* str) {
+void* Kotlin_Interop_CreateNSStringFromKString(const ArrayHeader* str) {
   RuntimeAssert(false, "Objective-C interop is disabled");
   return nullptr;
 }
 
-OBJ_GETTER(CreateKStringFromNSString, void* str) {
+OBJ_GETTER(Kotlin_Interop_CreateKStringFromNSString, void* str) {
   RuntimeAssert(false, "Objective-C interop is disabled");
   RETURN_OBJ(nullptr);
 }
 
+OBJ_GETTER(Kotlin_Interop_ObjCToString, KNativePtr ptr) {
+  RuntimeAssert(false, "Objective-C interop is disabled");
+  RETURN_OBJ(nullptr);
+}
+
+KInt Kotlin_Interop_ObjCHashCode(KNativePtr ptr) {
+  RuntimeAssert(false, "Objective-C interop is disabled");
+  return 0;
+}
+
+KBoolean Kotlin_Interop_ObjCEquals(KNativePtr ptr, KNativePtr otherPtr) {
+  RuntimeAssert(false, "Objective-C interop is disabled");
+  return 0;
+}
+
 } // extern "C"
 
 #endif // KONAN_OBJC_INTEROP