From e028bcbb04767ece227659a3877ea1aa45052c14 Mon Sep 17 00:00:00 2001
From: Veloman Yunkan <veloman.yunkan@gmail.com>
Date: Sun, 6 Dec 2020 00:12:52 +0400
Subject: [PATCH] Android's java.io.FileDescriptor is different

---
 src/wrapper/java/kiwixreader.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/wrapper/java/kiwixreader.cpp b/src/wrapper/java/kiwixreader.cpp
index c3f06ecc5..df32595ed 100644
--- a/src/wrapper/java/kiwixreader.cpp
+++ b/src/wrapper/java/kiwixreader.cpp
@@ -52,6 +52,14 @@ int jni2fd(const jobject& fdObj, JNIEnv* env)
 {
   jclass class_fdesc = env->FindClass("java/io/FileDescriptor");
   jfieldID field_fd = env->GetFieldID(class_fdesc, "fd", "I");
+  if ( field_fd == NULL )
+  {
+    env->ExceptionClear();
+    // Under Android the (private) 'fd' field of java.io.FileDescriptor has been
+    // renamed to 'descriptor'. See, for example,
+    // https://android.googlesource.com/platform/libcore/+/refs/tags/android-8.1.0_r1/ojluni/src/main/java/java/io/FileDescriptor.java#55
+    field_fd = env->GetFieldID(class_fdesc, "descriptor", "I");
+  }
   return env->GetIntField(fdObj, field_fd);
 }