From 7d5588ef4d23bbc4cc93ad1c3253b4167343cbe3 Mon Sep 17 00:00:00 2001
From: Andre Staltz <andre@staltz.com>
Date: Fri, 19 Jan 2024 12:47:52 +0200
Subject: [PATCH] new API onRecordDeletedOrErased

---
 lib/index.js                             | 19 ++++++--
 test/on-record-deleted-or-erased.test.js | 56 ++++++++++++++++++++++++
 2 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 test/on-record-deleted-or-erased.test.js

diff --git a/lib/index.js b/lib/index.js
index 557397e..2446109 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -197,6 +197,8 @@ function initDB(peer, config) {
   const encryptionFormats = new Map()
   /** @type {Obz<Rec>} */
   const onRecordAdded = Obz()
+  /** @type {Obz<MsgID>} */
+  const onRecordDeletedOrErased = Obz()
 
   const codec = {
     /**
@@ -879,7 +881,7 @@ function initDB(peer, config) {
    * @param {{
    *   keypair?: Keypair;
    *   encryptionFormat?: string;
-   *   data: any;
+   *   data: Record<string, any>;
    *   domain: string;
    *   account: string;
    *   tangles?: Array<MsgID>;
@@ -1036,7 +1038,12 @@ function initDB(peer, config) {
     }
     recs[seq] = null
     log.onDrain(() => {
-      log.del(offset, cb)
+      log.del(offset, (err) => {
+        // prettier-ignore
+        if (err) return cb(new Error('del() failed to write to disk', { cause: err }))
+        queueMicrotask(() => onRecordDeletedOrErased.set(msgID))
+        cb()
+      })
     })
   }
 
@@ -1126,7 +1133,12 @@ function initDB(peer, config) {
     }
     recs[seq] = rec
     log.onDrain(() => {
-      log.overwrite(offset, rec, cb)
+      log.overwrite(offset, rec, (err) => {
+        // prettier-ignore
+        if (err) return cb(new Error('erase() failed to write to disk', { cause: err }))
+        queueMicrotask(() => onRecordDeletedOrErased.set(msgID))
+        cb()
+      })
     })
   }
 
@@ -1180,6 +1192,7 @@ function initDB(peer, config) {
       getMinDepth: getMinGhostDepth,
     },
     onRecordAdded,
+    onRecordDeletedOrErased,
     getTangle,
     msgs,
     records,
diff --git a/test/on-record-deleted-or-erased.test.js b/test/on-record-deleted-or-erased.test.js
new file mode 100644
index 0000000..2f43560
--- /dev/null
+++ b/test/on-record-deleted-or-erased.test.js
@@ -0,0 +1,56 @@
+const test = require('node:test')
+const assert = require('node:assert')
+const path = require('node:path')
+const os = require('node:os')
+const p = require('node:util').promisify
+const rimraf = require('rimraf')
+const Keypair = require('ppppp-keypair')
+const { createPeer } = require('./util')
+
+const DIR = path.join(os.tmpdir(), 'ppppp-db-on-record-deleted-or-erased')
+rimraf.sync(DIR)
+
+test('onRecordDeletedOrErased()', async (t) => {
+  const peer = createPeer({
+    keypair: Keypair.generate('ed25519', 'alice'),
+    path: DIR,
+  })
+
+  await peer.db.loaded()
+
+  const id = await p(peer.db.account.create)({
+    subdomain: 'person',
+    _nonce: 'alice',
+  })
+
+  const msgIDs = []
+  for (let i = 0; i < 5; i++) {
+    const rec = await p(peer.db.feed.publish)({
+      account: id,
+      domain: 'post',
+      data: { text: 'm' + i },
+    })
+    msgIDs.push(rec.id)
+  }
+
+  const listened1 = []
+  const remove1 = peer.db.onRecordDeletedOrErased((msgID) => {
+    listened1.push(msgID)
+  })
+  assert.deepEqual(listened1, [], '(nothing)')
+  await p(peer.db.erase)(msgIDs[2])
+  assert.deepEqual(listened1, [msgIDs[2]], 'erased')
+  remove1()
+
+  const listened2 = []
+  const remove2 = peer.db.onRecordDeletedOrErased((msgID) => {
+    listened2.push(msgID)
+  })
+  assert.deepEqual(listened2, [msgIDs[2]], 'erased')
+  await p(peer.db.del)(msgIDs[1])
+  assert.deepEqual(listened2, [msgIDs[2], msgIDs[1]], 'erased and deleted')
+  remove2()
+
+  assert.deepEqual(listened1, [msgIDs[2]], 'erased') // still the same
+  await p(peer.close)(true)
+})