Fix loss of filename extension due to DocumentFile.renameTo()

When DocumentFile.renameTo() is called on a SAF URI, the file extension
is preserved, but this is not the case for file URIs. This commit
introduces an extension method .renameToPreserveExt() that behaves the
same regardless of URI.

Signed-off-by: Andrew Gunnerson <accounts+github@chiller3.com>

app/src/main/java/com/chiller3/bcr/DocumentFileExtensions.kt

@@ -1,9 +1,11 @@
 package com.chiller3.bcr
 
+import android.content.ContentResolver
 import android.content.Context
 import android.net.Uri
 import android.provider.DocumentsContract
 import android.util.Log
+import android.webkit.MimeTypeMap
 import androidx.documentfile.provider.DocumentFile
 
 private const val TAG = "DocumentFileExtensions"
@@ -98,3 +100,27 @@ fun DocumentFile.findFileFast(displayName: String): DocumentFile? {
 
     return null
 }
+
+/**
+ * Like [DocumentFile.renameTo], but preserves the extension for file URIs.
+ *
+ * This fixes [DocumentFile.renameTo]'s behavior so it is the same for both SAF and file URIs.
+ */
+fun DocumentFile.renameToPreserveExt(displayName: String): Boolean {
+    val newName = when (uri.scheme) {
+        ContentResolver.SCHEME_FILE -> {
+            buildString {
+                append(displayName)
+
+                val ext = MimeTypeMap.getSingleton().getExtensionFromMimeType(type)
+                if (ext != null) {
+                    append('.')
+                    append(ext)
+                }
+            }
+        }
+        else -> displayName
+    }
+
+    return renameTo(newName)
+}

app/src/main/java/com/chiller3/bcr/RecorderThread.kt

@@ -266,7 +266,7 @@ class RecorderThread(
                     if (finalFilename != initialFilename) {
                         Log.i(tag, "Renaming ${redactor.redact(initialFilename)} to ${redactor.redact(finalFilename)}")
 
-                        if (outputFile.renameTo(finalFilename)) {
+                        if (outputFile.renameToPreserveExt(finalFilename)) {
                             resultUri = outputFile.uri
                         } else {
                             Log.w(tag, "Failed to rename to final filename: ${redactor.redact(finalFilename)}")
@@ -381,7 +381,7 @@ class RecorderThread(
             if (finalLogcatFilename != logcatFilename) {
                 Log.i(tag, "Renaming ${redactor.redact(logcatFilename)} to ${redactor.redact(finalLogcatFilename)}")
 
-                if (!logcatFile.renameTo(finalLogcatFilename)) {
+                if (!logcatFile.renameToPreserveExt(finalLogcatFilename)) {
                     Log.w(tag, "Failed to rename to final filename: ${redactor.redact(finalLogcatFilename)}")
                 }
             }