Add support for Keypath filtering in notifications

CHANGELOG.md

@@ -4,6 +4,7 @@
 * None.
 
 ### Enhancements
+* Added support for keypaths in `asFlow()` methods on objects and queries. This makes it possible to control which properties will trigger change events, including properties on objects below the default nested limit of 4. (Issue [#661](https://github.com/realm/realm-kotlin/issues/661))
 * Support for experimental K2-compilation with `kotlin.experimental.tryK2=true`. (Issue [#1483](https://github.com/realm/realm-kotlin/issues/1483))
 
 ### Fixed

packages/cinterop/src/commonMain/kotlin/io/realm/kotlin/internal/interop/RealmInterop.kt

@@ -69,6 +69,7 @@ interface RealmCallbackTokenT : CapiT
 interface RealmNotificationTokenT : CapiT
 interface RealmChangesT : CapiT
 interface RealmSchedulerT : CapiT
+interface RealmKeyPathArrayT : CapiT
 
 // Public type aliases binding to internal verbose type safe type definitions. This should allow us
 // to easily change implementation details later on.
@@ -88,6 +89,7 @@ typealias RealmCallbackTokenPointer = NativePointer<RealmCallbackTokenT>
 typealias RealmNotificationTokenPointer = NativePointer<RealmNotificationTokenT>
 typealias RealmChangesPointer = NativePointer<RealmChangesT>
 typealias RealmSchedulerPointer = NativePointer<RealmSchedulerT>
+typealias RealmKeyPathArrayPointer = NativePointer<RealmKeyPathArrayT>
 
 // Sync types
 // Pure marker interfaces corresponding to the C-API realm_x_t struct types
@@ -435,24 +437,30 @@ expect object RealmInterop {
     ): RealmObjectPointer?
     fun realm_object_delete(obj: RealmObjectPointer)
 
+    fun realm_create_key_paths_array(realm: RealmPointer, clazz: ClassKey, keyPaths: List<String>): RealmKeyPathArrayPointer
     fun realm_object_add_notification_callback(
         obj: RealmObjectPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer
     fun realm_results_add_notification_callback(
         results: RealmResultsPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer
     fun realm_list_add_notification_callback(
         list: RealmListPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer
     fun realm_set_add_notification_callback(
         set: RealmSetPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer
     fun realm_dictionary_add_notification_callback(
         map: RealmMapPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer
     fun realm_object_changes_get_modified_properties(

packages/cinterop/src/jvm/kotlin/io/realm/kotlin/internal/interop/RealmInterop.kt

@@ -813,14 +813,22 @@ actual object RealmInterop {
         return realmc.realm_dictionary_is_valid(dictionary.cptr())
     }
 
+    actual fun realm_create_key_paths_array(realm: RealmPointer, clazz: ClassKey, keyPaths: List<String>): RealmKeyPathArrayPointer {
+        val ptr = realmc.realm_create_key_path_array(realm.cptr(), clazz.key, keyPaths.size, keyPaths.toTypedArray())
+        return LongPointerWrapper(ptr)
+    }
+
     actual fun realm_object_add_notification_callback(
         obj: RealmObjectPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer {
+
         return LongPointerWrapper(
             realmc.register_notification_cb(
                 obj.cptr(),
                 CollectionType.RLM_COLLECTION_TYPE_NONE.nativeValue,
+                keyPaths?.cptr() ?: 0,
                 object : NotificationCallback {
                     override fun onChange(pointer: Long) {
                         callback.onChange(LongPointerWrapper(realmc.realm_clone(pointer), true))
@@ -833,11 +841,13 @@ actual object RealmInterop {
 
     actual fun realm_results_add_notification_callback(
         results: RealmResultsPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer {
         return LongPointerWrapper(
             realmc.register_results_notification_cb(
                 results.cptr(),
+                keyPaths?.cptr() ?: 0,
                 object : NotificationCallback {
                     override fun onChange(pointer: Long) {
                         callback.onChange(LongPointerWrapper(realmc.realm_clone(pointer), true))
@@ -850,12 +860,14 @@ actual object RealmInterop {
 
     actual fun realm_list_add_notification_callback(
         list: RealmListPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer {
         return LongPointerWrapper(
             realmc.register_notification_cb(
                 list.cptr(),
                 CollectionType.RLM_COLLECTION_TYPE_LIST.nativeValue,
+                keyPaths?.cptr() ?: 0,
                 object : NotificationCallback {
                     override fun onChange(pointer: Long) {
                         callback.onChange(LongPointerWrapper(realmc.realm_clone(pointer), true))
@@ -868,12 +880,14 @@ actual object RealmInterop {
 
     actual fun realm_set_add_notification_callback(
         set: RealmSetPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer {
         return LongPointerWrapper(
             realmc.register_notification_cb(
                 set.cptr(),
                 CollectionType.RLM_COLLECTION_TYPE_SET.nativeValue,
+                keyPaths?.cptr() ?: 0,
                 object : NotificationCallback {
                     override fun onChange(pointer: Long) {
                         callback.onChange(LongPointerWrapper(realmc.realm_clone(pointer), true))
@@ -886,12 +900,14 @@ actual object RealmInterop {
 
     actual fun realm_dictionary_add_notification_callback(
         map: RealmMapPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer {
         return LongPointerWrapper(
             realmc.register_notification_cb(
                 map.cptr(),
                 CollectionType.RLM_COLLECTION_TYPE_DICTIONARY.nativeValue,
+                keyPaths?.cptr() ?: 0,
                 object : NotificationCallback {
                     override fun onChange(pointer: Long) {
                         callback.onChange(LongPointerWrapper(realmc.realm_clone(pointer), true))

packages/cinterop/src/nativeDarwin/kotlin/io/realm/kotlin/internal/interop/RealmInterop.kt

@@ -45,6 +45,7 @@ import kotlinx.cinterop.COpaquePointer
 import kotlinx.cinterop.CPointed
 import kotlinx.cinterop.CPointer
 import kotlinx.cinterop.CPointerVar
+import kotlinx.cinterop.CPointerVarOf
 import kotlinx.cinterop.CValue
 import kotlinx.cinterop.CVariable
 import kotlinx.cinterop.LongVar
@@ -70,6 +71,7 @@ import kotlinx.cinterop.readValue
 import kotlinx.cinterop.refTo
 import kotlinx.cinterop.set
 import kotlinx.cinterop.staticCFunction
+import kotlinx.cinterop.toCStringArray
 import kotlinx.cinterop.toKString
 import kotlinx.cinterop.useContents
 import kotlinx.cinterop.usePinned
@@ -1653,8 +1655,17 @@ actual object RealmInterop {
         checkedBooleanResult(realm_wrapper.realm_object_delete(obj.cptr()))
     }
 
+    actual fun realm_create_key_paths_array(realm: RealmPointer, clazz: ClassKey, keyPaths: List<String>): RealmKeyPathArrayPointer {
+        memScoped {
+            val userKeyPaths: CPointer<CPointerVarOf<CPointer<ByteVarOf<Byte>>>> = keyPaths.toCStringArray(this)
+            val keyPathPointer = realm_wrapper.realm_create_key_path_array(realm.cptr(), clazz.key.toUInt(), keyPaths.size, userKeyPaths)
+            return CPointerWrapper(keyPathPointer)
+        }
+    }
+
     actual fun realm_object_add_notification_callback(
         obj: RealmObjectPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer {
         return CPointerWrapper(
@@ -1667,7 +1678,7 @@ actual object RealmInterop {
                         ?.dispose()
                         ?: error("Notification callback data should never be null")
                 },
-                null, // See https://github.com/realm/realm-kotlin/issues/661
+                keyPaths?.cptr(),
                 staticCFunction { userdata, change -> // Change callback
                     try {
                         userdata?.asStableRef<Callback<RealmChangesPointer>>()
@@ -1688,6 +1699,7 @@ actual object RealmInterop {
 
     actual fun realm_results_add_notification_callback(
         results: RealmResultsPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer {
         return CPointerWrapper(
@@ -1700,7 +1712,7 @@ actual object RealmInterop {
                         ?.dispose()
                         ?: error("Notification callback data should never be null")
                 },
-                null, // See https://github.com/realm/realm-kotlin/issues/661
+                keyPaths?.cptr(),
                 staticCFunction { userdata, change -> // Change callback
                     try {
                         userdata?.asStableRef<Callback<RealmChangesPointer>>()
@@ -1721,6 +1733,7 @@ actual object RealmInterop {
 
     actual fun realm_list_add_notification_callback(
         list: RealmListPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer {
         return CPointerWrapper(
@@ -1732,7 +1745,7 @@ actual object RealmInterop {
                     userdata?.asStableRef<Callback<RealmChangesPointer>>()?.dispose()
                         ?: error("Notification callback data should never be null")
                 },
-                null, // See https://github.com/realm/realm-kotlin/issues/661
+                keyPaths?.cptr(),
                 staticCFunction { userdata, change -> // Change callback
                     try {
                         userdata?.asStableRef<Callback<RealmChangesPointer>>()
@@ -1753,6 +1766,7 @@ actual object RealmInterop {
 
     actual fun realm_set_add_notification_callback(
         set: RealmSetPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer {
         return CPointerWrapper(
@@ -1765,7 +1779,7 @@ actual object RealmInterop {
                         ?.dispose()
                         ?: error("Notification callback data should never be null")
                 },
-                null, // See https://github.com/realm/realm-kotlin/issues/661
+                keyPaths?.cptr(),
                 staticCFunction { userdata, change -> // Change callback
                     try {
                         userdata?.asStableRef<Callback<RealmChangesPointer>>()
@@ -1786,6 +1800,7 @@ actual object RealmInterop {
 
     actual fun realm_dictionary_add_notification_callback(
         map: RealmMapPointer,
+        keyPaths: RealmKeyPathArrayPointer?,
         callback: Callback<RealmChangesPointer>
     ): RealmNotificationTokenPointer {
         return CPointerWrapper(
@@ -1798,7 +1813,7 @@ actual object RealmInterop {
                         ?.dispose()
                         ?: error("Notification callback data should never be null")
                 },
-                null, // See https://github.com/realm/realm-kotlin/issues/661
+                keyPaths?.cptr(),
                 staticCFunction { userdata, change -> // Change callback
                     try {
                         userdata?.asStableRef<Callback<RealmChangesPointer>>()

packages/jni-swig-stub/realm.i

@@ -301,7 +301,8 @@ return $jnicall;
                realm_flx_sync_mutable_subscription_set_t*, realm_flx_sync_subscription_desc_t*,
                realm_set_t*, realm_async_open_task_t*, realm_dictionary_t*,
                realm_sync_session_connection_state_notification_token_t*,
-               realm_dictionary_changes_t*, realm_scheduler_t*, realm_sync_socket_t* };
+               realm_dictionary_changes_t*, realm_scheduler_t*, realm_sync_socket_t*,
+               realm_key_path_array_t* };
 
 // For all functions returning a pointer or bool, check for null/false and throw an error if
 // realm_get_last_error returns true.
@@ -397,6 +398,66 @@ import static io.realm.kotlin.internal.interop.realm_errno_e.*;
 %include "enumtypeunsafe.swg"
 %javaconst(1);
 
+// Add support for String[] vs char** conversion
+// See https://www.swig.org/Doc4.0/Java.html#Java_converting_java_string_arrays
+// Begin --
+
+/* This tells SWIG to treat char ** as a special case when used as a parameter
+   in a function call */
+%typemap(in) char ** (jint size) {
+    int i = 0;
+    size = jenv->GetArrayLength($input);
+    $1 = (char **) malloc((size+1)*sizeof(char *));
+    /* make a copy of each string */
+    for (i = 0; i<size; i++) {
+        jstring j_string = (jstring)jenv->GetObjectArrayElement($input, i);
+        const char * c_string = jenv->GetStringUTFChars(j_string, 0);
+        $1[i] = (char*) malloc((strlen(c_string)+1)*sizeof(char));
+        strcpy($1[i], c_string);
+        jenv->ReleaseStringUTFChars(j_string, c_string);
+        jenv->DeleteLocalRef(j_string);
+    }
+    $1[i] = 0;
+}
+
+/* This cleans up the memory we malloc'd before the function call */
+%typemap(freearg) char ** {
+    int i;
+    for (i=0; i<size$argnum-1; i++) {
+        free($1[i]);
+    }
+    free($1);
+}
+
+/* This allows a C function to return a char ** as a Java String array */
+%typemap(out) char ** {
+    int i;
+    int len=0;
+    jstring temp_string;
+    const jclass clazz = jenv->FindClass("java/lang/String");
+
+    while ($1[len]) len++;
+    jresult = jenv->NewObjectArray(len, clazz, NULL);
+    /* exception checking omitted */
+    for (i=0; i<len; i++) {
+        temp_string = (*jenv)->NewStringUTF(*result++);
+        jenv->SetObjectArrayElement(jresult, i, temp_string);
+        jenv->DeleteLocalRef(temp_string);
+    }
+}
+
+/* These 3 typemaps tell SWIG what JNI and Java types to use */
+%typemap(jni) char ** "jobjectArray"
+%typemap(jtype) char ** "String[]"
+%typemap(jstype) char ** "String[]"
+
+/* These 2 typemaps handle the conversion of the jtype to jstype typemap type
+   and vice versa */
+%typemap(javain) char ** "$javainput"
+%typemap(javaout) char ** {
+    return $jnicall;
+}
+// -- End
 
 // FIXME OPTIMIZE Support getting/setting multiple attributes. Ignored for now due to incorrect
 //  type cast in Swig-generated wrapper for "const realm_property_key_t*" which is not cast
@@ -430,6 +491,12 @@ import static io.realm.kotlin.internal.interop.realm_errno_e.*;
 //  realm_convert_with_path.
 %ignore realm_convert_with_path;
 
+%ignore "realm_object_add_notification_callback";
+%ignore "realm_list_add_notification_callback";
+%ignore "realm_set_add_notification_callback";
+%ignore "realm_dictionary_add_notification_callback";
+%ignore "realm_results_add_notification_callback";
+
 // Swig doesn't understand __attribute__ so eliminate it
 #define __attribute__(x)