From 17d24400906235a172fc760e98656589692f798a Mon Sep 17 00:00:00 2001
From: Jean-Michel Trivi <jmtrivi@google.com>
Date: Wed, 14 Sep 2016 12:37:40 -0700
Subject: [PATCH] MediaScanner: check build fingerprint for system sound scan

Always scan notification, ringtones and alarm files under /system
  when the build fingerprint has changed since the last scan,
  because the dates on those files is not set correctly
  (by design), and hence cannot be trusted in the date-based
  scanning logic.
Remove some dead code

Bug 30476971

Change-Id: I638c787dc177f7f5fb17c1c2a576be190c1c85f9
---
 media/java/android/media/MediaScanner.java | 51 +++++++++++++++-------
 1 file changed, 36 insertions(+), 15 deletions(-)

diff --git a/media/java/android/media/MediaScanner.java b/media/java/android/media/MediaScanner.java
index c8ab5f9bc429e..0fafe4b19a42c 100644
--- a/media/java/android/media/MediaScanner.java
+++ b/media/java/android/media/MediaScanner.java
@@ -21,12 +21,14 @@ import android.content.ContentResolver;
 import android.content.ContentUris;
 import android.content.ContentValues;
 import android.content.Context;
+import android.content.SharedPreferences;
 import android.database.Cursor;
 import android.database.SQLException;
 import android.drm.DrmManagerClient;
 import android.graphics.BitmapFactory;
 import android.mtp.MtpConstants;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Environment;
 import android.os.RemoteException;
 import android.os.SystemProperties;
@@ -153,6 +155,11 @@ public class MediaScanner implements AutoCloseable {
     private static final String MUSIC_DIR = "/music/";
     private static final String PODCAST_DIR = "/podcasts/";
 
+    public static final String SCANNED_BUILD_PREFS_NAME = "MediaScanBuild";
+    public static final String LAST_INTERNAL_SCAN_FINGERPRINT = "lastScanFingerprint";
+    private static final String SYSTEM_SOUNDS_DIR = "/system/media/audio";
+    private static String sLastInternalScanFingerprint;
+
     private static final String[] ID3_GENRES = {
         // ID3v1 Genres
         "Blues",
@@ -402,6 +409,13 @@ public class MediaScanner implements AutoCloseable {
         mMediaProvider = mContext.getContentResolver()
                 .acquireContentProviderClient(MediaStore.AUTHORITY);
 
+        if (sLastInternalScanFingerprint == null) {
+            final SharedPreferences scanSettings =
+                    mContext.getSharedPreferences(SCANNED_BUILD_PREFS_NAME, Context.MODE_PRIVATE);
+            sLastInternalScanFingerprint =
+                    scanSettings.getString(LAST_INTERNAL_SCAN_FINGERPRINT, new String());
+        }
+
         mAudioUri = Audio.Media.getContentUri(volumeName);
         mVideoUri = Video.Media.getContentUri(volumeName);
         mImagesUri = Images.Media.getContentUri(volumeName);
@@ -585,16 +599,24 @@ public class MediaScanner implements AutoCloseable {
                     entry.mRowId = 0;
                 }
 
-                if (entry.mPath != null &&
-                        ((!mDefaultNotificationSet &&
+                if (entry.mPath != null) {
+                    if (((!mDefaultNotificationSet &&
                                 doesPathHaveFilename(entry.mPath, mDefaultNotificationFilename))
                         || (!mDefaultRingtoneSet &&
                                 doesPathHaveFilename(entry.mPath, mDefaultRingtoneFilename))
                         || (!mDefaultAlarmSet &&
                                 doesPathHaveFilename(entry.mPath, mDefaultAlarmAlertFilename)))) {
-                    Log.w(TAG, "forcing rescan of " + entry.mPath +
-                            "since ringtone setting didn't finish");
-                    scanAlways = true;
+                        Log.w(TAG, "forcing rescan of " + entry.mPath +
+                                "since ringtone setting didn't finish");
+                        scanAlways = true;
+                    } else if (isSystemSoundWithMetadata(entry.mPath)
+                            && !Build.FINGERPRINT.equals(sLastInternalScanFingerprint)) {
+                        // file is located on the system partition where the date cannot be trusted:
+                        // rescan if the build fingerprint has changed since the last scan.
+                        Log.i(TAG, "forcing rescan of " + entry.mPath
+                                + " since build fingerprint changed");
+                        scanAlways = true;
+                    }
                 }
 
                 // rescan for metadata if file was modified since last scan
@@ -1128,6 +1150,15 @@ public class MediaScanner implements AutoCloseable {
 
     }; // end of anonymous MediaScannerClient instance
 
+    private static boolean isSystemSoundWithMetadata(String path) {
+        if (path.startsWith(SYSTEM_SOUNDS_DIR + ALARMS_DIR)
+                || path.startsWith(SYSTEM_SOUNDS_DIR + RINGTONES_DIR)
+                || path.startsWith(SYSTEM_SOUNDS_DIR + NOTIFICATIONS_DIR)) {
+            return true;
+        }
+        return false;
+    }
+
     private String settingSetIndicatorName(String base) {
         return base + "_set";
     }
@@ -1252,16 +1283,6 @@ public class MediaScanner implements AutoCloseable {
         }
     }
 
-    private boolean inScanDirectory(String path, String[] directories) {
-        for (int i = 0; i < directories.length; i++) {
-            String directory = directories[i];
-            if (path.startsWith(directory)) {
-                return true;
-            }
-        }
-        return false;
-    }
-
     private void pruneDeadThumbnailFiles() {
         HashSet<String> existingFiles = new HashSet<String>();
         String directory = "/sdcard/DCIM/.thumbnails";