Android: Fix opening games with extensionless URI

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/ContentHandler.java

@@ -99,6 +99,12 @@ public class ContentHandler
     return -1;
   }
 
+  @Nullable @Keep
+  public static String getDisplayName(String uri)
+  {
+    return getDisplayName(Uri.parse(uri));
+  }
+
   @Nullable
   public static String getDisplayName(@NonNull Uri uri)
   {

Source/Android/jni/AndroidCommon/AndroidCommon.cpp

@@ -112,6 +112,15 @@ jlong GetAndroidContentSizeAndIsDirectory(const std::string& uri)
                                    ToJString(env, uri));
 }
 
+std::string GetAndroidContentDisplayName(const std::string& uri)
+{
+  JNIEnv* env = IDCache::GetEnvForThread();
+  jobject display_name =
+      env->CallStaticObjectMethod(IDCache::GetContentHandlerClass(),
+                                  IDCache::GetContentHandlerGetDisplayName(), ToJString(env, uri));
+  return display_name ? GetJString(env, reinterpret_cast<jstring>(display_name)) : "";
+}
+
 int GetNetworkIpAddress()
 {
   JNIEnv* env = IDCache::GetEnvForThread();

Source/Android/jni/AndroidCommon/AndroidCommon.h

@@ -28,6 +28,12 @@ bool DeleteAndroidContent(const std::string& uri);
 // Returns -1 if not found, -2 if directory, file size otherwise.
 jlong GetAndroidContentSizeAndIsDirectory(const std::string& uri);
 
+// An unmangled URI (one which the C++ code has not appended anything to) can't be relied on
+// to contain a file name at all. If a file name is desired, this function is the most reliable
+// way to get it, but the display name is not guaranteed to always actually be like a file name.
+// An empty string will be returned for files which do not exist.
+std::string GetAndroidContentDisplayName(const std::string& uri);
+
 int GetNetworkIpAddress();
 int GetNetworkPrefixLength();
 int GetNetworkGateway();

Source/Android/jni/AndroidCommon/IDCache.cpp

@@ -45,6 +45,7 @@ static jclass s_content_handler_class;
 static jmethodID s_content_handler_open_fd;
 static jmethodID s_content_handler_delete;
 static jmethodID s_content_handler_get_size_and_is_directory;
+static jmethodID s_content_handler_get_display_name;
 
 static jclass s_network_helper_class;
 static jmethodID s_network_helper_get_network_ip_address;
@@ -216,6 +217,11 @@ jmethodID GetContentHandlerGetSizeAndIsDirectory()
   return s_content_handler_get_size_and_is_directory;
 }
 
+jmethodID GetContentHandlerGetDisplayName()
+{
+  return s_content_handler_get_display_name;
+}
+
 jclass GetNetworkHelperClass()
 {
   return s_network_helper_class;
@@ -315,6 +321,8 @@ jint JNI_OnLoad(JavaVM* vm, void* reserved)
       env->GetStaticMethodID(s_content_handler_class, "delete", "(Ljava/lang/String;)Z");
   s_content_handler_get_size_and_is_directory = env->GetStaticMethodID(
       s_content_handler_class, "getSizeAndIsDirectory", "(Ljava/lang/String;)J");
+  s_content_handler_get_display_name = env->GetStaticMethodID(
+      s_content_handler_class, "getDisplayName", "(Ljava/lang/String;)Ljava/lang/String;");
 
   const jclass network_helper_class =
       env->FindClass("org/dolphinemu/dolphinemu/utils/NetworkHelper");

Source/Android/jni/AndroidCommon/IDCache.h

@@ -45,6 +45,7 @@ jclass GetContentHandlerClass();
 jmethodID GetContentHandlerOpenFd();
 jmethodID GetContentHandlerDelete();
 jmethodID GetContentHandlerGetSizeAndIsDirectory();
+jmethodID GetContentHandlerGetDisplayName();
 
 jclass GetNetworkHelperClass();
 jmethodID GetNetworkHelperGetNetworkIpAddress();

Source/Core/Core/Boot/Boot.cpp

@@ -158,6 +158,15 @@ BootParameters::GenerateFromFile(std::vector<std::string> paths,
   if (paths.size() == 1)
     paths.clear();
 
+#ifdef ANDROID
+  if (extension.empty() && IsPathAndroidContent(path))
+  {
+    const std::string display_name = GetAndroidContentDisplayName(path);
+    SplitPath(display_name, nullptr, nullptr, &extension);
+    std::transform(extension.begin(), extension.end(), extension.begin(), ::tolower);
+  }
+#endif
+
   static const std::unordered_set<std::string> disc_image_extensions = {
       {".gcm", ".iso", ".tgc", ".wbfs", ".ciso", ".gcz", ".wia", ".rvz", ".dol", ".elf"}};
   if (disc_image_extensions.find(extension) != disc_image_extensions.end() || is_drive)