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fix(driver-historian-wonderware-client): resolve Medium code-review finding (Driver.Historian.Wonderware.Client-005)

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Replace the synchronous non-cancellable _stream.ReadByte() for the kind byte
in FrameReader.ReadFrameAsync with an async ReadExactAsync(new byte[1], ct)
call so the full frame read honours the EffectiveCallTimeout-linked token
and cannot wedge the call gate when the sidecar stalls mid-frame.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Joseph Doherty
2026-05-22 09:19:14 -04:00
parent 6bb971c040
commit 75580fb432
2 changed files with 9 additions and 5 deletions
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4
code-reviews/Driver.Historian.Wonderware.Client/findings.md
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@@ -141,7 +141,7 @@ counters under one lock acquisition.
| Severity | Medium |
| Category | Error handling & resilience |
| Location | `Ipc/FrameReader.cs:31-32` |
| Status | Open |
| Status | Resolved |
**Description:** After reading the 4-byte length prefix, `ReadFrameAsync` reads the kind
byte with the synchronous, blocking `_stream.ReadByte()` and ignores the
@@ -158,7 +158,7 @@ prefix read to 5 bytes, or do a second `ReadExactAsync(new byte[1], ct)`. This m
whole frame read honor the call-timeout token and matches the async style of the rest of
the reader.
**Resolution:** _(open)_
**Resolution:** Resolved 2026-05-22 — replaced the synchronous, non-cancellable `_stream.ReadByte()` for the kind byte with an async `ReadExactAsync(new byte[1], ct)` call so the full frame read honours the call-timeout token and cannot wedge the channel on a stalled peer.
### Driver.Historian.Wonderware.Client-006

10
src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware.Client/Ipc/FrameReader.cs
View File

@@ -28,14 +28,18 @@ public sealed class FrameReader : IDisposable
if (length < 0 || length > Framing.MaxFrameBodyBytes)
throw new InvalidDataException($"Sidecar IPC frame length {length} out of range.");
var kindByte = _stream.ReadByte();
if (kindByte < 0) throw new EndOfStreamException("EOF after length prefix, before kind byte.");
// Read the kind byte asynchronously and cancellably — a synchronous ReadByte()
// blocks the thread-pool thread and cannot be interrupted by the call-timeout token
// if the peer stalls mid-frame (finding 005).
var kindBuffer = new byte[Framing.KindByteSize];
if (!await ReadExactAsync(kindBuffer, ct).ConfigureAwait(false))
throw new EndOfStreamException("EOF after length prefix, before kind byte.");
var body = new byte[length];
if (!await ReadExactAsync(body, ct).ConfigureAwait(false))
throw new EndOfStreamException("EOF mid-frame.");
return ((MessageKind)(byte)kindByte, body);
return ((MessageKind)kindBuffer[0], body);
}
public static T Deserialize<T>(byte[] body) => MessagePackSerializer.Deserialize<T>(body);