fix: sanitize filenames before saving (#270)

* Fix "Replace characters on save as function, FileNotFoundException" #250

* Update CHANGELOG.md

update changelog

* Update app/src/main/kotlin/org/fossify/filemanager/activities/SaveAsActivity.kt

Co-authored-by: Naveen Singh <36371707+naveensingh@users.noreply.github.com>

* Update CHANGELOG.md

Co-authored-by: Naveen Singh <36371707+naveensingh@users.noreply.github.com>

* Update CHANGELOG.md

Co-authored-by: Naveen Singh <36371707+naveensingh@users.noreply.github.com>

---------

Co-authored-by: Jan Guegel <jan@guegel.eu>
Co-authored-by: Naveen Singh <36371707+naveensingh@users.noreply.github.com>

Refs: https://github.com/FossifyOrg/File-Manager/issues/250

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 ### Fixed
 - Fixed folders showing up incorrectly as files in copy/move dialog ([#267])
+- Fixed error when saving files with unsupported characters ([#250])
 
 ## [1.2.3] - 2025-09-15
 ### Fixed
@@ -74,6 +75,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [#176]: https://github.com/FossifyOrg/File-Manager/issues/176
 [#251]: https://github.com/FossifyOrg/File-Manager/issues/251
 [#267]: https://github.com/FossifyOrg/File-Manager/issues/267
+[#250]: https://github.com/FossifyOrg/File-Manager/issues/250
 
 [Unreleased]: https://github.com/FossifyOrg/File-Manager/compare/1.2.3...HEAD
 [1.2.3]: https://github.com/FossifyOrg/File-Manager/compare/1.2.2...1.2.3

app/src/main/kotlin/org/fossify/filemanager/activities/SaveAsActivity.kt

@@ -36,8 +36,9 @@ class SaveAsActivity : SimpleActivity() {
                             }
 
                             val source = intent.getParcelableExtra<Uri>(Intent.EXTRA_STREAM)!!
-                            val filename = getFilenameFromContentUri(source)
+                            val originalFilename = getFilenameFromContentUri(source)
                                 ?: source.toString().getFilenameFromPath()
+                            val filename = sanitizeFilename(originalFilename)
                             val mimeType = contentResolver.getType(source)
                                 ?: intent.type?.takeIf { it != "*/*" }
                                 ?: filename.getMimeType()
@@ -66,4 +67,9 @@ class SaveAsActivity : SimpleActivity() {
         super.onResume()
         setupToolbar(binding.activitySaveAsToolbar, NavigationIcon.Arrow)
     }
+
+    private fun sanitizeFilename(filename: String): String {
+        return filename.replace("[/\\\\<>:\"|?*\u0000-\u001F]".toRegex(), "_")
+            .takeIf { it.isNotBlank() } ?: "unnamed_file"
+    }
 }