Fix screenshot failure with transcoding

We currently attempt to convert transcode fds to original fds inside
the platform media players. This causes screenshot
failures in ExifInterface. To mitigate, we only match published videos
in DCIM/Camera.

Bug: 173543930
Bug: 175831095
Test: atest FileUtilsTest#testConvertToModernFd
Test: Manual, tested by both taking a screenshot and video transcoding.

Change-Id: I4abba3d9d36e83c5a019b32793bd38fee81d5f75

1 files changed, 17 insertions, 4 deletions

diff --git a/core/java/android/os/FileUtils.java b/core/java/android/os/FileUtils.java
index 92fe98ca1044..c014ef682a24 100644
--- a/core/java/android/os/FileUtils.java
+++ b/core/java/android/os/FileUtils.java
@@ -83,6 +83,7 @@ import java.security.NoSuchAlgorithmException;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Comparator;
+import java.util.Locale;
 import java.util.Objects;
 import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
@@ -115,6 +116,9 @@ public final class FileUtils {
     private FileUtils() {
     }
 
+    private static final String CAMERA_DIR_LOWER_CASE = "/storage/emulated/" + UserHandle.myUserId()
+            + "/dcim/camera";
+
     /** Regular expression for safe filenames: no spaces or metacharacters.
       *
       * Use a preload holder so that FileUtils can be compile-time initialized.
@@ -1432,18 +1436,27 @@ public final class FileUtils {
         }
     }
 
+    // TODO(b/170488060): Consider better approach
     /** {@hide} */
+    @VisibleForTesting
     public static FileDescriptor convertToModernFd(FileDescriptor fd) {
         try {
             Context context = AppGlobals.getInitialApplication();
+            File realFile = ParcelFileDescriptor.getFile(fd);
+            String fileName = realFile.getName();
+            boolean isCameraVideo = !fileName.startsWith(".") && fileName.endsWith(".mp4")
+                    && contains(CAMERA_DIR_LOWER_CASE, realFile.getAbsolutePath().toLowerCase(
+                                    Locale.ROOT));
+
             if (!SystemProperties.getBoolean("sys.fuse.transcode_enabled", false)
-                    || UserHandle.getAppId(Process.myUid()) == getMediaProviderAppId(context)) {
-                // If transcode is enabled we optimize by default, unless explicitly disabled.
-                // Never convert modern fd for MediaProvider, because this requires
+                    || UserHandle.getAppId(Process.myUid()) == getMediaProviderAppId(context)
+                    || !isCameraVideo) {
+                // 1. If transcode is enabled we optimize by default, unless explicitly disabled.
+                // 2. Never convert modern fd for MediaProvider, because this requires
                 // MediaStore#scanFile and can cause infinite loops when MediaProvider scans
+                // 3. Only convert published mp4 videos in the DCIM/Camera dir
                 return null;
             }
-            File realFile = ParcelFileDescriptor.getFile(fd);
             Log.i(TAG, "Changing to modern format dataSource for: " + realFile);
             ContentResolver resolver = context.getContentResolver();