Fixes denoland#2033, shared queue push bug

ry · Apr 20, 2019 · 28721c4 · 28721c4
1 parent c8db224
commit 28721c4
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Showing 2 changed files with 47 additions and 2 deletions.
diff --git a/core/shared_queue.js b/core/shared_queue.js
@@ -1,4 +1,20 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+/*
+SharedQueue Binary Layout
++-------------------------------+-------------------------------+
+| NUM_RECORDS (32) |
++---------------------------------------------------------------+
+| NUM_SHIFTED_OFF (32) |
++---------------------------------------------------------------+
+| HEAD (32) |
++---------------------------------------------------------------+
+| OFFSETS (32) |
++---------------------------------------------------------------+
+| RECORD_ENDS (*MAX_RECORDS) ...
++---------------------------------------------------------------+
+| RECORDS (*MAX_RECORDS) ...
++---------------------------------------------------------------+
+ */
 
 (window => {
  const GLOBAL_NAMESPACE = "Deno";

diff --git a/core/shared_queue.rs b/core/shared_queue.rs
@@ -1,4 +1,21 @@
 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
+/*
+SharedQueue Binary Layout
++-------------------------------+-------------------------------+
+| NUM_RECORDS (32) |
++---------------------------------------------------------------+
+| NUM_SHIFTED_OFF (32) |
++---------------------------------------------------------------+
+| HEAD (32) |
++---------------------------------------------------------------+
+| OFFSETS (32) |
++---------------------------------------------------------------+
+| RECORD_ENDS (*MAX_RECORDS) ...
++---------------------------------------------------------------+
+| RECORDS (*MAX_RECORDS) ...
++---------------------------------------------------------------+
+ */
+
 use crate::libdeno::deno_buf;
 
 const MAX_RECORDS: usize = 100;
@@ -127,11 +144,11 @@ impl SharedQueue {
  pub fn push(&mut self, record: &[u8]) -> bool {
  let off = self.head();
  let end = off + record.len();
- let index = self.num_records();
- if end > self.bytes.len() {
+ if end > self.bytes.len() || self.num_records() >= MAX_RECORDS {
  debug!("WARNING the sharedQueue overflowed");
  return false;
  }
+ let index = self.num_records();
  self.set_end(index, end);
  assert_eq!(end - off, record.len());
  self.bytes[off..end].copy_from_slice(record);
@@ -213,4 +230,16 @@ mod tests {
  assert_eq!(q.shift().unwrap().len(), 1);
  assert_eq!(q.size(), 0);
  }
+
+ #[test]
+ fn full_records() {
+ let mut q = SharedQueue::new(RECOMMENDED_SIZE);
+ for _ in 0..MAX_RECORDS {
+ assert!(q.push(&alloc_buf(1)))
+ }
+ assert_eq!(q.push(&alloc_buf(1)), false);
+ // Even if we shift one off, we still cannot push a new record.
+ assert_eq!(q.shift().unwrap().len(), 1);
+ assert_eq!(q.push(&alloc_buf(1)), false);
+ }
 }