Sync constructor (#591)

* wip

* checkpoint

* tests pass now

* add safe close api on core and move replicator there

* more stuff in core

* all hooks live in core

* inline replicator

* premerge

* no need to skip

* add static helper for making core cores

* bye bye non-sparse mode

* Core manages replicator lifecycle (#592)

* state unref is sync

* core closes storage

* replicator no longer needs session

* remove force close from session

* fix bad condition

* core being set is invariant

* remove stale method

* query sessions on underlying core

* move autoClose onto Core

* rename close to destroy

* core destroys state

* preload is now simply a promise

* preload promise can return opts

* no need to check if state is active

* add onidle hook

* idle waits for mutex to be free also

* remove from option

* exclusive sessions

* always emit close

* fix test

* pass userdata to create for atomicity

* core always refs default state

* session explicitly refs state

---------

Co-authored-by: Christophe Diederichs <[email protected]>
Co-authored-by: Christophe Diederichs <[email protected]>

Author: mafintosh

index.js

@@ -1,3 +1,4 @@
+const crypto = require('hypercore-crypto')
 const flat = require('flat-tree')
 const b4a = require('b4a')
 const quickbit = require('quickbit-universal')
@@ -89,7 +90,7 @@ async function flushBatch (prologue, src, dst, batch) {
   // reads done!
 
   if (batch.first) {
-    const treeHash = dst.crypto.tree(nodes.slice(0, batch.roots.length))
+    const treeHash = crypto.tree(nodes.slice(0, batch.roots.length))
     if (!b4a.equals(treeHash, prologue.hash)) throw new Error('Prologue does not match source')
   }
 
@@ -178,7 +179,7 @@ async function flushBatch (prologue, src, dst, batch) {
 function signalReplicator (core, upgraded, start, length) {
   const status = upgraded ? 0b0011 : 0b0010
   const bitfield = { drop: false, start, length }
-  core.onupdate({ status, bitfield, value: null, from: null })
+  core._onupdate({ status, bitfield, value: null, from: null })
 }
 
 function prologueToTree (prologue) {