implemented a lot of features

database/migrations/1768620764820_add_crcs_to_parts.ts

@@ -0,0 +1,30 @@
+import { BaseSchema } from '@adonisjs/lucid/schema'
+
+/**
+ * yEnc CRCs of body-derived articles, so split volumes can be verified
+ * without downloading them (CONCEPT.md D20): the combined part CRCs of a
+ * volume must equal the whole-file crc32 in its last part.
+ */
+export default class extends BaseSchema {
+  async up() {
+    for (const tableName of ['parts', 'part_conflicts']) {
+      this.schema.alterTable(tableName, (table) => {
+        table.string('pcrc32', 8)
+        // Decoded length of the part (=ypart end - begin + 1).
+        table.integer('part_size')
+        // Whole-file CRC32, when the poster included it (usually in the last part).
+        table.string('file_crc32', 8)
+      })
+    }
+  }
+
+  async down() {
+    for (const tableName of ['parts', 'part_conflicts']) {
+      this.schema.alterTable(tableName, (table) => {
+        table.dropColumn('pcrc32')
+        table.dropColumn('part_size')
+        table.dropColumn('file_crc32')
+      })
+    }
+  }
+}