From dcd42b7048a177ef09503dd90f1bfd670da54cb1 Mon Sep 17 00:00:00 2001
From: Thibault Deckers <thibault.deckers@gmail.com>
Date: Tue, 11 Mar 2025 00:24:03 +0100
Subject: [PATCH] #1471 check file length after metadata editing via PixyMeta

---
 .../thibault/aves/metadata/PixyMetaHelper.kt  |  1 +
 .../aves/model/provider/ImageProvider.kt      | 26 +++++++++++++++----
 .../info/metadata/metadata_section.dart       |  2 +-
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/android/app/src/main/kotlin/deckers/thibault/aves/metadata/PixyMetaHelper.kt b/android/app/src/main/kotlin/deckers/thibault/aves/metadata/PixyMetaHelper.kt
index 04e5365ef..e1d11786e 100644
--- a/android/app/src/main/kotlin/deckers/thibault/aves/metadata/PixyMetaHelper.kt
+++ b/android/app/src/main/kotlin/deckers/thibault/aves/metadata/PixyMetaHelper.kt
@@ -92,6 +92,7 @@ object PixyMetaHelper {
 
     fun getXmp(input: InputStream): XMP? = Metadata.readMetadata(input)[MetadataType.XMP] as XMP?
 
+    // PixyMeta may fail with just a log, and write nothing to the output
     fun setXmp(
         input: InputStream,
         output: OutputStream,
diff --git a/android/app/src/main/kotlin/deckers/thibault/aves/model/provider/ImageProvider.kt b/android/app/src/main/kotlin/deckers/thibault/aves/model/provider/ImageProvider.kt
index 39fbf091d..9d36f1812 100644
--- a/android/app/src/main/kotlin/deckers/thibault/aves/model/provider/ImageProvider.kt
+++ b/android/app/src/main/kotlin/deckers/thibault/aves/model/provider/ImageProvider.kt
@@ -680,18 +680,19 @@ abstract class ImageProvider {
         try {
             edit(ExifInterface(editableFile))
 
+            if (editableFile.length() == 0L) {
+                callback.onFailure(Exception("editing Exif yielded an empty file"))
+                return false
+            }
+
             val editedMimeType = detectMimeType(context, Uri.fromFile(editableFile), mimeType)
             if (editedMimeType != mimeType) {
                 throw Exception("editing Exif changes mimeType=$mimeType -> $editedMimeType for uri=$uri path=$path")
             }
 
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
-                // 1) as of androidx.exifinterface:exifinterface:1.3.6, editing some specific WEBP
-                // makes them undecodable by some decoders (including Android's and Chrome's)
-                // even though `BitmapFactory` successfully decodes their bounds,
+                // editing may corrupt the file for various reasons,
                 // so we check whether decoding it throws an exception
-                // 2) some users have reported corruption when editing JPEG as well,
-                // but conditions are unknown (specific image, custom ROM, low storage, race condition, etc.)
                 ImageDecoder.decodeBitmap(ImageDecoder.createSource(editableFile))
             }
 
@@ -781,6 +782,11 @@ abstract class ImageProvider {
                 }
             }
 
+            if (editableFile.length() == 0L) {
+                callback.onFailure(Exception("editing IPTC yielded an empty file"))
+                return false
+            }
+
             if (trailerVideoBytes != null) {
                 // append trailer video, if any
                 editableFile.appendBytes(trailerVideoBytes!!)
@@ -917,6 +923,11 @@ abstract class ImageProvider {
             }
         }
 
+        if (editableFile.length() == 0L) {
+            callback.onFailure(Exception("editing XMP yielded an empty file"))
+            return false
+        }
+
         try {
             // copy the edited temporary file back to the original
             editableFile.transferTo(outputStream(context, mimeType, uri, path))
@@ -1330,6 +1341,11 @@ abstract class ImageProvider {
             }
         }
 
+        if (editableFile.length() == 0L) {
+            callback.onFailure(Exception("removing metadata yielded an empty file"))
+            return
+        }
+
         try {
             // copy the edited temporary file back to the original
             editableFile.transferTo(outputStream(context, mimeType, uri, path))
diff --git a/lib/widgets/viewer/info/metadata/metadata_section.dart b/lib/widgets/viewer/info/metadata/metadata_section.dart
index bd0d34c34..00f24d51f 100644
--- a/lib/widgets/viewer/info/metadata/metadata_section.dart
+++ b/lib/widgets/viewer/info/metadata/metadata_section.dart
@@ -144,8 +144,8 @@ class _MetadataSectionSliverState extends State<MetadataSectionSliver> {
   }
 
   Future<void> _getMetadata() async {
-    if (!mounted) return;
     final titledDirectories = await entry.getMetadataDirectories(context);
+    if (!mounted) return;
     metadataNotifier.value = Map.fromEntries(titledDirectories);
     _expandedDirectoryNotifier.value = null;
   }