Add job to fix digests for duplicate attachments.

app/src/main/java/org/thoughtcrime/securesms/database/AttachmentTable.kt

@@ -446,6 +446,17 @@ class AttachmentTable(
       }
   }
 
+  fun getMostRecentValidAttachmentUsingDataFile(dataFile: String): DatabaseAttachment? {
+    return readableDatabase
+      .select(*PROJECTION)
+      .from(TABLE_NAME)
+      .where("$DATA_FILE = ? AND $TRANSFER_STATE = $TRANSFER_PROGRESS_DONE", dataFile)
+      .orderBy("$ID DESC")
+      .limit(1)
+      .run()
+      .readToSingleObject { it.readAttachment() }
+  }
+
   fun hasAttachment(id: AttachmentId): Boolean {
     return readableDatabase
       .exists(TABLE_NAME)
@@ -1397,6 +1408,31 @@ class AttachmentTable(
       .readToList { AttachmentId(it.requireLong(ID)) }
   }
 
+  /**
+   * A query for a specific migration. Retrieves attachments that we'd need to create a new digest for.
+   * This is basically all attachments that have data and are finished downloading.
+   */
+  fun getDataFilesWithMultipleValidAttachments(): List<String> {
+    val targetDataFile = "target_data_file"
+    return readableDatabase
+      .select("DISTINCT($DATA_FILE) AS $targetDataFile")
+      .from(TABLE_NAME)
+      .where(
+        """
+        $targetDataFile NOT NULL AND 
+        $TRANSFER_STATE = $TRANSFER_PROGRESS_DONE AND (
+          SELECT COUNT(*) 
+          FROM $TABLE_NAME 
+          WHERE 
+            $DATA_FILE = $targetDataFile AND
+            $TRANSFER_STATE = $TRANSFER_PROGRESS_DONE
+        ) > 1
+        """
+      )
+      .run()
+      .readToList { it.requireNonNullString(targetDataFile) }
+  }
+
   /**
    * As part of the digest backfill process, this updates the (key, IV, digest) tuple for an attachment.
    */
@@ -1412,6 +1448,21 @@ class AttachmentTable(
       .run()
   }
 
+  /**
+   * As part of the digest backfill process, this updates the (key, IV, digest) tuple for all attachments that share a data file (and are done downloading).
+   */
+  fun updateKeyIvDigestByDataFile(dataFile: String, key: ByteArray, iv: ByteArray, digest: ByteArray) {
+    writableDatabase
+      .update(TABLE_NAME)
+      .values(
+        REMOTE_KEY to Base64.encodeWithPadding(key),
+        REMOTE_IV to iv,
+        REMOTE_DIGEST to digest
+      )
+      .where("$DATA_FILE = ? AND $TRANSFER_STATE = $TRANSFER_PROGRESS_DONE", dataFile)
+      .run()
+  }
+
   /**
    * Inserts new attachments in the table. The [Attachment]s may or may not have data, depending on whether it's an attachment we created locally or some
    * inbound attachment that we haven't fetched yet.