Fix full download crashing in new schema case

This worked in my initial testing, but with a smaller collection, the
UI is now racing with the download on my machine:

- getSyncStatus() was assuming col.db would still be open by the time
it gets around to calling methods on it
- onCreateOptionsMenu() likewise assumes that if colIsOpen() returns true,
it is free to call methods on it

A better way way to fix this would be to wrap all collection access in a mutex,
so that the collection is never touched without the lock being acquired.
Code holding the mutex could then be guaranteed that the collection is open
and valid for the duration of its run. Changing all that legacy code is
a big task however.

I've added a lock to the upload case as well, as it's possible it's
likewise buggy and just not triggering on my machine.

AnkiDroid/src/main/java/com/ichi2/anki/DeckPicker.kt

@@ -619,7 +619,7 @@ open class DeckPicker :
                 return true
             }
         })
-        if (colIsOpen()) {
+        if (colIsOpen() && !CollectionHelper.getInstance().isCollectionLocked) {
             displaySyncBadge(menu)
 
             // Show / hide undo

AnkiDroid/src/main/java/com/ichi2/anki/Sync.kt

@@ -166,16 +166,19 @@ private suspend fun handleDownload(
         extractProgress = fullDownloadProgress(col.tr.syncDownloadingFromAnkiweb()),
         onCancel = ::cancelSync
     ) {
-        col.createBackup(
-            BackupManager.getBackupDirectoryFromCollection(col.path),
-            force = true,
-            waitForCompletion = true
-        )
-        col.close(save = true, downgrade = false, forFullSync = true)
+        val helper = CollectionHelper.getInstance()
+        helper.lockCollection()
         try {
+            col.createBackup(
+                BackupManager.getBackupDirectoryFromCollection(col.path),
+                force = true,
+                waitForCompletion = true
+            )
+            col.close(save = true, downgrade = false, forFullSync = true)
             col.fullDownload(auth)
         } finally {
             col.reopen(afterFullSync = true)
+            helper.unlockCollection()
         }
     }
 
@@ -193,11 +196,14 @@ private suspend fun handleUpload(
         extractProgress = fullDownloadProgress(col.tr.syncUploadingToAnkiweb()),
         onCancel = ::cancelSync
     ) {
+        val helper = CollectionHelper.getInstance()
+        helper.lockCollection()
         col.close(save = true, downgrade = false, forFullSync = true)
         try {
             col.fullUpload(auth)
         } finally {
             col.reopen(afterFullSync = true)
+            helper.unlockCollection()
         }
     }
     Timber.i("Full Upload Completed")

AnkiDroid/src/main/java/com/ichi2/utils/SyncStatus.kt

@@ -30,14 +30,15 @@ enum class SyncStatus {
 
         @JvmStatic
         fun getSyncStatus(getCol: Supplier<Collection>): SyncStatus {
-            val col: Collection
-            col = try {
-                getCol.get()
+            return try {
+                val col = getCol.get()
+                // may fail when the collection is closed for a full sync,
+                // as col.db is null
+                getSyncStatus(col)
             } catch (e: Exception) {
                 Timber.w(e)
                 return INCONCLUSIVE
             }
-            return getSyncStatus(col)
         }
 
         @JvmStatic