From 1b404bef1d7fd4d06cc230f4bb4a57ff12826948 Mon Sep 17 00:00:00 2001
From: Jeff Sharkey <jsharkey@android.com>
Date: Fri, 1 Mar 2019 11:31:30 -0700
Subject: [PATCH] Include UUID in MediaStore version.

This allows apps to detect when a user clears data on MediaProvider,
or when the internal database is wiped due to corruption.

Bug: 126274540
Test: atest android.provider.cts.MediaStoreTest
Change-Id: Idfcdbf441aea82c581b7270a6d4663136b8931e2
---
 api/current.txt                            |  3 +-
 core/java/android/provider/MediaStore.java | 48 ++++++++++++++++------
 2 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/api/current.txt b/api/current.txt
index 395145e03dec2..9dbfd51e98710 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -38411,7 +38411,8 @@ package android.provider {
     method @Nullable public static android.net.Uri getDocumentUri(@NonNull android.content.Context, @NonNull android.net.Uri);
     method public static android.net.Uri getMediaScannerUri();
     method @Nullable public static android.net.Uri getMediaUri(@NonNull android.content.Context, @NonNull android.net.Uri);
-    method public static String getVersion(android.content.Context);
+    method @NonNull public static String getVersion(@NonNull android.content.Context);
+    method @NonNull public static String getVersion(@NonNull android.content.Context, @NonNull String);
     method @NonNull public static String getVolumeName(@NonNull android.net.Uri);
     method @NonNull public static android.net.Uri setIncludePending(@NonNull android.net.Uri);
     method @NonNull public static android.net.Uri setRequireOriginal(@NonNull android.net.Uri);
diff --git a/core/java/android/provider/MediaStore.java b/core/java/android/provider/MediaStore.java
index a34ac706c406c..917b5c2615dbf 100644
--- a/core/java/android/provider/MediaStore.java
+++ b/core/java/android/provider/MediaStore.java
@@ -145,6 +145,8 @@ public final class MediaStore {
      */
     public static final String RETRANSLATE_CALL = "update_titles";
 
+    /** {@hide} */
+    public static final String GET_VERSION_CALL = "get_version";
     /** {@hide} */
     public static final String GET_DOCUMENT_URI_CALL = "get_document_uri";
     /** {@hide} */
@@ -3318,21 +3320,41 @@ public final class MediaStore {
     public static final String MEDIA_IGNORE_FILENAME = ".nomedia";
 
     /**
-     * Get the media provider's version.
-     * Applications that import data from the media provider into their own caches
-     * can use this to detect that the media provider changed, and reimport data
-     * as needed. No other assumptions should be made about the meaning of the version.
-     * @param context Context to use for performing the query.
-     * @return A version string, or null if the version could not be determined.
+     * Return an opaque version string describing the {@link MediaStore} state.
+     * <p>
+     * Applications that import data from {@link MediaStore} into their own
+     * caches can use this to detect that {@link MediaStore} has undergone
+     * substantial changes, and that data should be rescanned.
+     * <p>
+     * No other assumptions should be made about the meaning of the version.
+     * <p>
+     * This method returns the version for {@link MediaStore#VOLUME_EXTERNAL};
+     * to obtain a version for a different volume, use
+     * {@link #getVersion(Context, String)}.
      */
-    public static String getVersion(Context context) {
-        final Uri uri = AUTHORITY_URI.buildUpon().appendPath("none").appendPath("version").build();
-        try (Cursor c = context.getContentResolver().query(uri, null, null, null, null)) {
-            if (c.moveToFirst()) {
-                return c.getString(0);
-            }
+    public static @NonNull String getVersion(@NonNull Context context) {
+        return getVersion(context, VOLUME_EXTERNAL);
+    }
+
+    /**
+     * Return an opaque version string describing the {@link MediaStore} state.
+     * <p>
+     * Applications that import data from {@link MediaStore} into their own
+     * caches can use this to detect that {@link MediaStore} has undergone
+     * substantial changes, and that data should be rescanned.
+     * <p>
+     * No other assumptions should be made about the meaning of the version.
+     */
+    public static @NonNull String getVersion(@NonNull Context context, @NonNull String volumeName) {
+        final ContentResolver resolver = context.getContentResolver();
+        try (ContentProviderClient client = resolver.acquireContentProviderClient(AUTHORITY)) {
+            final Bundle in = new Bundle();
+            in.putString(Intent.EXTRA_TEXT, volumeName);
+            final Bundle out = client.call(GET_VERSION_CALL, null, in);
+            return out.getString(Intent.EXTRA_TEXT);
+        } catch (RemoteException e) {
+            throw e.rethrowAsRuntimeException();
         }
-        return null;
     }
 
     /**