moveTo acquires lock

holepunchto · Dec 18, 2024 · fae5047 · fae5047
1 parent bcf8e43
commit fae5047
Showing 1 changed file with 33 additions and 27 deletions.
diff --git a/lib/session-state.js b/lib/session-state.js
@@ -543,48 +543,54 @@ module.exports = class SessionState {
   async moveTo (core, length, { atom } = {}) {
     const state = core.state
 
-    if (state.storage && (await state.storage.openBatch(this.name)) !== null) {
-      throw STORAGE_CONFLICT('Batch has already been created')
-    }
+    const lock = await this.mutex.lock(atom)
 
-    const head = this.core.sessionStates.pop()
-    if (head !== this) this.core.sessionStates[(head.index = this.index)] = head
+    try {
+      if (state.storage && (await state.storage.openBatch(this.name)) !== null) {
+        throw STORAGE_CONFLICT('Batch has already been created')
+      }
 
-    this.core = core
-    this.index = this.core.sessionStates.push(this) - 1
+      const head = this.core.sessionStates.pop()
+      if (head !== this) this.core.sessionStates[(head.index = this.index)] = head
 
-    if (atom) atom.enter()
+      this.core = core
+      this.index = this.core.sessionStates.push(this) - 1
 
-    const treeLength = this.tree.length
+      if (atom) atom.enter()
 
-    if (!this.isSnapshot()) {
-      const truncation = length < this.tree.length ? await truncateAndFlush(this, length, atom) : null
+      const treeLength = this.tree.length
 
-      const treeInfo = truncation ? truncation.tree : await state._getTreeHeadAt(this.tree.length)
-      const prologue = state.tree.prologue
+      if (!this.isSnapshot()) {
+        const truncation = length < this.tree.length ? await truncateAndFlush(this, length, atom) : null
 
-      // todo: validate treeInfo
+        const treeInfo = truncation ? truncation.tree : await state._getTreeHeadAt(this.tree.length)
+        const prologue = state.tree.prologue
 
-      const registration = state.storage.registerBatch(this.name, treeInfo)
+        // todo: validate treeInfo
 
-      if (atom) atom.exit()
+        const registration = state.storage.registerBatch(this.name, treeInfo)
 
-      if (truncation) await truncation.flushing
-      this.storage = await registration
+        if (atom) atom.exit()
 
-      this.tree = await MerkleTree.open(this.storage, treeInfo.length, { prologue })
+        if (truncation) await truncation.flushing
+        this.storage = await registration
 
-      if (truncation) {
-        await truncation.flushing
-        const { dependency, treeUpdate, tree } = truncation
+        this.tree = await MerkleTree.open(this.storage, treeInfo.length, { prologue })
 
-        if (dependency) this.storage.updateDependencies(dependency.length)
-        this.tree.onupdate(treeUpdate)
-        this.ontruncate(tree, tree.length, treeLength)
+        if (truncation) {
+          await truncation.flushing
+          const { dependency, treeUpdate, tree } = truncation
+
+          if (dependency) this.storage.updateDependencies(dependency.length)
+          this.tree.onupdate(treeUpdate)
+          this.ontruncate(tree, tree.length, treeLength)
+        }
       }
-    }
 
-    for (const s of this.sessions) s.transferSession(this.core)
+      for (const s of this.sessions) s.transferSession(this.core)
+    } finally {
+      lock.release()
+    }
   }
 
   async createSession (name, length, overwrite, draft) {