Fix path to Preference file if it contains a invalid path character (#750)

* Fix path to shared preference files if it contains a invalid character

* Lint

AndroidCompat/src/main/java/xyz/nulldev/androidcompat/io/sharedprefs/JavaSharedPreferences.kt

@@ -19,6 +19,7 @@ import kotlinx.serialization.SerializationException
 import kotlinx.serialization.builtins.SetSerializer
 import kotlinx.serialization.builtins.serializer
 import mu.KotlinLogging
+import xyz.nulldev.androidcompat.util.SafePath
 import xyz.nulldev.ts.config.ApplicationRootDir
 import java.util.Properties
 import kotlin.io.path.Path
@@ -34,7 +35,12 @@ class JavaSharedPreferences(key: String) : SharedPreferences {
         private val logger = KotlinLogging.logger {}
     }
 
-    private val file = Path(ApplicationRootDir, "settings", "$key.xml")
+    private val file =
+        Path(
+            ApplicationRootDir,
+            "settings",
+            "${SafePath.buildValidFilename(key)}.xml",
+        )
     private val properties =
         Properties().also { properties ->
             try {

AndroidCompat/src/main/java/xyz/nulldev/androidcompat/util/SafePath.kt

@@ -0,0 +1,47 @@
+package xyz.nulldev.androidcompat.util
+
+/*
+ * Copyright (C) Contributors to the Suwayomi project
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// adopted from: https://github.com/tachiyomiorg/tachiyomi/blob/4cefbce7c34e724b409b6ba127f3c6c5c346ad8d/app/src/main/java/eu/kanade/tachiyomi/util/storage/DiskUtil.kt
+object SafePath {
+    /**
+     * Mutate the given filename to make it valid for a FAT filesystem,
+     * replacing any invalid characters with "_". This method doesn't allow hidden files (starting
+     * with a dot), but you can manually add it later.
+     */
+    fun buildValidFilename(origName: String): String {
+        val name = origName.trim('.', ' ')
+        if (name.isEmpty()) {
+            return "(invalid)"
+        }
+        val sb = StringBuilder(name.length)
+        name.forEach { c ->
+            if (isValidFatFilenameChar(c)) {
+                sb.append(c)
+            } else {
+                sb.append('_')
+            }
+        }
+        // Even though vfat allows 255 UCS-2 chars, we might eventually write to
+        // ext4 through a FUSE layer, so use that limit minus 15 reserved characters.
+        return sb.toString().take(240)
+    }
+
+    /**
+     * Returns true if the given character is a valid filename character, false otherwise.
+     */
+    private fun isValidFatFilenameChar(c: Char): Boolean {
+        if (0x00.toChar() <= c && c <= 0x1f.toChar()) {
+            return false
+        }
+        return when (c) {
+            '"', '*', '/', ':', '<', '>', '?', '\\', '|', 0x7f.toChar() -> false
+            else -> true
+        }
+    }
+}