Make sure we clean up the pre-processed and uploaded media (#5039)

* Add `MediaSender.cleanUp()` and `MediaPreProcessor.cleanUp()` methods: this will remove the temporary files created when pre-processing media before sending them.

* Make sure we clean up also the previous temporary media.

* Fix the condition for the custom back handler in the attachments preview screen

* Tests: check the clean up is performed when needed

libraries/mediaupload/impl/src/main/kotlin/io/element/android/libraries/mediaupload/impl/AndroidMediaPreProcessor.kt

@@ -41,6 +41,7 @@ import kotlinx.coroutines.withContext
 import timber.log.Timber
 import java.io.File
 import java.io.InputStream
+import java.util.UUID
 import javax.inject.Inject
 import kotlin.time.Duration
 import kotlin.time.Duration.Companion.milliseconds
@@ -68,6 +69,9 @@ class AndroidMediaPreProcessor @Inject constructor(
 
     private val contentResolver = context.contentResolver
 
+    private val cacheDir = context.cacheDir
+    private val baseTmpFileDir = File(cacheDir, "uploads")
+
     override suspend fun process(
         uri: Uri,
         mimeType: String,
@@ -100,6 +104,28 @@ class AndroidMediaPreProcessor @Inject constructor(
         }
     }.mapFailure { MediaPreProcessor.Failure(it) }
 
+    override fun cleanUp() {
+        // Clear temporary files created in older versions of the app
+        cacheDir.listFiles()?.onEach { file ->
+            if (file.isFile) {
+                val nameWithoutExtension = file.nameWithoutExtension
+                // UUIDs are 36 characters long, so we check if we can take those 36 characters
+                val nameWithoutExtensionAndRandom = if (nameWithoutExtension.length > 36) {
+                    nameWithoutExtension.substring(0, 36)
+                } else {
+                    // Not a temp file
+                    return@onEach
+                }
+                val isUUID = tryOrNull { UUID.fromString(nameWithoutExtensionAndRandom) } != null
+                if (isUUID && file.extension.isNotEmpty()) {
+                    file.delete()
+                }
+            }
+        }
+        // Clear temporary files created by this pre-processor in the separate uploads directory
+        baseTmpFileDir.listFiles()?.onEach { it.delete() }
+    }
+
     private suspend fun processFile(uri: Uri, mimeType: String): MediaUploadInfo {
         val file = copyToTmpFile(uri)
         val info = FileInfo(
@@ -280,7 +306,10 @@ class AndroidMediaPreProcessor @Inject constructor(
     private suspend fun createTmpFileWithInput(inputStream: InputStream): File? {
         return withContext(coroutineDispatchers.io) {
             tryOrNull {
-                val tmpFile = context.createTmpFile()
+                if (!baseTmpFileDir.exists()) {
+                    baseTmpFileDir.mkdirs()
+                }
+                val tmpFile = context.createTmpFile(baseTmpFileDir)
                 tmpFile.outputStream().use { inputStream.copyTo(it) }
                 tmpFile
             }