feat: core.purge with rocksdb storage

Author: Mauve Signweaver

index.js

@@ -867,7 +867,6 @@ class Hypercore extends EventEmitter {
   }
 
   async purge() {
-    await this._closeAllSessions(null)
     await this.core.purge()
   }
 

lib/core.js

@@ -909,6 +909,17 @@ module.exports = class Core {
     for (const s of weakSessions) s.close().catch(noop)
   }
 
+  async purge() {
+    if (this.opened === false) await this.opening
+    const tx = this.storage.write()
+    tx.deleteTreeNodeRange(0, -1)
+    tx.deleteBlockRange(0, -1)
+    this.bitfield.clear(tx)
+    await tx.flush()
+    await this.closeAllSessions()
+    await this.close()
+  }
+
   async _close() {
     if (this.opened === false) await this.opening
     if (this.hasSession() === true) throw new Error('Cannot close while sessions are open')

test/all.js

@@ -26,7 +26,7 @@ async function runTests() {
   await import('./move-to.js')
   await import('./mutex.js')
   await import('./preload.js')
-  // await import('./purge.js') // todo: implement purge
+  await import('./purge.js')
   await import('./push.js')
   await import('./remote-bitfield.js')
   await import('./remote-length.js')

test/helpers/index.js

@@ -109,3 +109,9 @@ exports.replicateDebugStream = function replicate(a, b, t, opts = {}) {
 exports.eventFlush = async function eventFlush() {
   await new Promise((resolve) => setImmediate(resolve))
 }
+
+exports.toArray = async function toArray(stream) {
+  const all = []
+  for await (const data of stream) all.push(data)
+  return all
+}

test/purge.js

@@ -1,33 +1,33 @@
 const test = require('brittle')
-const fs = require('fs')
-const Path = require('path')
 
-const Hypercore = require('..')
+const Hypercore = require('../')
+const { createStorage, toArray } = require('./helpers')
 
 test('basic purge', async function (t) {
   const dir = await t.tmp()
-  const core = new Hypercore(dir)
+  const storage = await createStorage(t, dir)
+  const core = new Hypercore(storage)
+
   await core.append(['a', 'b', 'c'])
 
-  const oplogLoc = Path.join(dir, 'oplog')
-  const treeLoc = Path.join(dir, 'tree')
-  const bitfieldLoc = Path.join(dir, 'bitfield')
-  const dataLoc = Path.join(dir, 'data')
+  // Sanity check for core having data
+  t.is(core.length, 3)
 
-  t.is(fs.existsSync(oplogLoc), true)
-  t.is(fs.existsSync(treeLoc), true)
-  t.is(fs.existsSync(bitfieldLoc), true)
-  t.is(fs.existsSync(dataLoc), true)
-  t.is(fs.readdirSync(dir).length, 4) // Sanity check
+  const discoveryKey = core.discoveryKey
 
   await core.purge()
 
-  t.is(core.closed, true)
-  t.is(fs.existsSync(oplogLoc), false)
-  t.is(fs.existsSync(treeLoc), false)
-  t.is(fs.existsSync(bitfieldLoc), false)
-  t.is(fs.existsSync(dataLoc), false)
-  t.is(fs.readdirSync(dir).length, 0) // Nothing remains
+  const reopenedStorage = await createStorage(t, dir)
+  const coreStorage = await reopenedStorage.resumeCore(discoveryKey)
+
+  const allBlocks = await toArray(coreStorage.createBlockStream())
+  t.is(allBlocks.length, 0)
+
+  const allTreeNodes = await toArray(coreStorage.createTreeNodeStream())
+  t.is(allTreeNodes.length, 0)
+
+  const allBitfieldPages = await toArray(coreStorage.createBitfieldStream())
+  t.is(allBitfieldPages.length, 0)
 })
 
 test('purge closes all sessions', async function (t) {