Add a few source helper functions

app/src/main/java/exh/GalleryAdder.kt

@@ -37,8 +37,7 @@ class GalleryAdder {
     fun pickSource(url: String): List<UrlImportableSource> {
         val uri = url.toUri()
         return sourceManager.getVisibleCatalogueSources()
-            .map { it.getMainSource() }
-            .filterIsInstance<UrlImportableSource>()
+            .mapNotNull { it.getMainSource<UrlImportableSource>() }
             .filter {
                 it.lang in filters.first && it.id !in filters.second && try {
                     it.matchesUri(uri)
@@ -71,8 +70,7 @@ class GalleryAdder {
                 }
             } else {
                 sourceManager.getVisibleCatalogueSources()
-                    .map { it.getMainSource() }
-                    .filterIsInstance<UrlImportableSource>()
+                    .mapNotNull { it.getMainSource<UrlImportableSource>() }
                     .find {
                         it.lang in filters.first && it.id !in filters.second && try {
                             it.matchesUri(uri)

app/src/main/java/exh/md/utils/MdUtil.kt

@@ -318,8 +318,7 @@ class MdUtil {
 
             return sourceManager.getVisibleOnlineSources()
                 .asSequence()
-                .map { it.getMainSource() }
-                .filterIsInstance<MangaDex>()
+                .mapNotNull { it.getMainSource<MangaDex>() }
                 .filter { it.lang in languages }
                 .filterNot { it.id.toString() in disabledSourceIds }
                 .toList()

app/src/main/java/exh/source/SourceHelper.kt

@@ -107,6 +107,13 @@ fun Source.getMainSource(): Source = if (this is EnhancedHttpSource) {
     this
 }
 
+@JvmName("getMainSourceInline")
+inline fun <reified T : Source> Source.getMainSource(): T? = if (this is EnhancedHttpSource) {
+    this.source() as? T
+} else {
+    this as? T
+}
+
 fun Source.getOriginalSource(): Source = if (this is EnhancedHttpSource) {
     this.originalSource
 } else {
@@ -118,3 +125,11 @@ fun Source.getEnhancedSource(): Source = if (this is EnhancedHttpSource) {
 } else {
     this
 }
+
+inline fun <reified T> Source.anyIs(): Boolean {
+    return if (this is EnhancedHttpSource) {
+        originalSource is T || enhancedSource is T
+    } else {
+        this is T
+    }
+}

app/src/main/java/exh/ui/metadata/MetadataViewPresenter.kt

@@ -30,8 +30,8 @@ class MetadataViewPresenter(
 
         launchIO {
             val flatMetadata = db.getFlatMetadataForManga(manga.id!!).executeOnIO() ?: return@launchIO
-            val mainSource = source.getMainSource()
-            if (mainSource is MetadataSource<*, *>) {
+            val mainSource = source.getMainSource<MetadataSource<*, *>>()
+            if (mainSource != null) {
                 meta.value = flatMetadata.raise(mainSource.metaClass)
             }
         }