feat: add file type validation for import

Adds validation to check the file type before importing kernel parameters. The import now only accepts text-based files.

Author: Lennoard

app/src/main/kotlin/com/androidvip/sysctlgui/ui/presets/PresetsScreen.kt

@@ -65,7 +65,7 @@ fun PresetsScreen(
         }
     )
     val createFileLauncher = rememberLauncherForActivityResult(
-        contract = ActivityResultContracts.CreateDocument("*/*"),
+        contract = ActivityResultContracts.CreateDocument("text/plain"),
         onResult = { uri ->
             viewModel.onEvent(PresetsViewEvent.BackUpFileCreated(uri))
         }

app/src/main/kotlin/com/androidvip/sysctlgui/ui/presets/PresetsViewModel.kt

@@ -7,6 +7,7 @@ import com.androidvip.sysctlgui.R
 import com.androidvip.sysctlgui.data.utils.PresetsFileProcessor
 import com.androidvip.sysctlgui.domain.StringProvider
 import com.androidvip.sysctlgui.domain.exceptions.EmptyFileException
+import com.androidvip.sysctlgui.domain.exceptions.InvalidFileException
 import com.androidvip.sysctlgui.domain.exceptions.MalformedLineException
 import com.androidvip.sysctlgui.domain.exceptions.NoValidParamException
 import com.androidvip.sysctlgui.domain.usecase.AddUserParamsUseCase
@@ -77,6 +78,8 @@ class PresetsViewModel(
                 setEffect { PresetsViewEffect.ShowError(stringProvider.getString(R.string.export_error_no_param)) }
             } catch (_: IOException) {
                 setEffect { PresetsViewEffect.ShowError(stringProvider.getString(R.string.export_error_io)) }
+            } catch (_: InvalidFileException) {
+                setEffect { PresetsViewEffect.ShowError(stringProvider.getString(R.string.import_error_invalid_type)) }
             } catch (e: Exception) {
                 Log.e("PresetsViewModel", "Error importing file", e)
                 setEffect { PresetsViewEffect.ShowError(stringProvider.getString(R.string.import_error)) }

app/src/main/res/values-pt-rBR/strings.xml

@@ -44,6 +44,7 @@
     <string name="tile_start_app_label">Iniciar o SysctlGUI</string>
     <string name="export_options">Opções de exportação</string>
     <string name="export_error_no_param">Falha: nenhum parâmetro encontrado</string>
+    <string name="import_error_invalid_type">Tipo de arquivo inválido</string>
     <string name="export_error_io">A exportação de parâmetros falhou devido a um erro do armazenamento</string>
     <string name="export_options_sum">Importar, exportar ou fazer backup dos parâmetros do kernel</string>
     <string name="browse">Nevegar</string>

app/src/main/res/values/strings.xml

@@ -42,6 +42,7 @@
     <string name="tile_toggle_start_up_label">Run Sysctl GUI at boot</string>
     <string name="tile_toggle_start_up_no_root_access_label">Requires root access</string>
     <string name="tile_toggle_start_up_no_root_access_toast">Root access required</string>
+    <string name="import_error_invalid_type">Invalid file type</string>
     <string name="export_error_io">Parameter export failed due to an IO error</string>
     <string name="export_error_no_param">Failed: no parameter found</string>
     <string name="export_options">Export options</string>

data/src/main/java/com/androidvip/sysctlgui/data/utils/PresetsFileProcessor.kt

@@ -3,6 +3,8 @@ package com.androidvip.sysctlgui.data.utils
 import android.content.ContentResolver
 import android.net.Uri
 import android.util.Log
+import android.webkit.MimeTypeMap
+import com.androidvip.sysctlgui.domain.exceptions.InvalidFileException
 import com.androidvip.sysctlgui.domain.exceptions.NoParameterFoundException
 import com.androidvip.sysctlgui.domain.models.KernelParam
 import com.androidvip.sysctlgui.utils.isValidSysctlOutputLine
@@ -18,6 +20,7 @@ class PresetsFileProcessor(
     suspend fun getKernelParamsFromUri(
         uri: Uri
     ): List<KernelParam> = withContext(ioDispatcher) {
+        checkFileType(uri)
         contentResolver.openInputStream(uri)?.use { inputStream ->
             val lines = inputStream.bufferedReader().readLines()
             val params = lines.mapNotNull { line ->
@@ -56,4 +59,19 @@ class PresetsFileProcessor(
             }
         } ?: throw IOException("Failed to open output stream for URI: $uri")
     }
-}
+
+
+    private suspend fun checkFileType(uri: Uri) = withContext(ioDispatcher) {
+        val mimeType = contentResolver.getType(uri)
+        if (mimeType != null && mimeType.startsWith("text/")) {
+            return@withContext // It's likely a text file, we're good.
+        }
+
+        val fileExtension = MimeTypeMap.getFileExtensionFromUrl(uri.toString()).lowercase()
+        val allowedExtensions = listOf("conf", "cfg", "config", "ini", "txt")
+
+        if (fileExtension in allowedExtensions) return@withContext
+
+        throw InvalidFileException("Unsupported file type. MIME type: $mimeType.")
+    }
+}

domain/src/main/java/com/androidvip/sysctlgui/domain/exceptions/ImportExceptions.kt

@@ -1,6 +1,9 @@
 package com.androidvip.sysctlgui.domain.exceptions
 
-class InvalidFileExtensionException : Exception()
+/**
+ * Thrown when an invalid file type is trying to be imported.
+ */
+class InvalidFileException(message: String) : Exception(message)
 /**
  * Thrown when an imported file is empty
  */