Adjust acquisition thread to never overwrite circular buffer, keep track of pending frames, always fetch oldest frame.

[Jakub Wlodek (jwlodek)]

• Use CIRC_NO_OVERWRITE mode, and keep track of frames pending in circular buffer. Also track dropped frames
• Remove defaults

[Copilot]

🟡 Changes recommended

Error and synchronization paths can leave frame-buffer state invalid or discard valid EOF notifications.

3 open findings

• Handle setup failure before using uninitialized frameBufferSize · New
• Avoid discarding pending frame callbacks during dequeue recovery · New
• Abort acquisition when unlocking the oldest frame fails · New

What changed in this PR

Updates continuous acquisition to preserve buffered frames and expose queue diagnostics/configuration.

Changes:

• Uses non-overwriting circular buffers and retrieves the oldest frame.
• Tracks pending and dropped frames.
• Adds configurable buffer sizing and unique-ID sources.

File	Description
kinetixApp/​src/​ADKinetixDS.h	Adds pending-frame state.
kinetixApp/​src/​ADKinetix.h	Defines new parameters and unique-ID options.
kinetixApp/​src/​ADKinetix.cpp	Implements buffered frame retrieval and diagnostics.
kinetixApp/​Db/​ADKinetix.template	Adds corresponding EPICS records.
kinetixApp/​Db/​ADKinetix_settings.req	Persists new configurable settings.

🧠 Review effort: Balanced

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[Copilot]

🔵 Needs a closer look

Failed dequeues can erase concurrently delivered EOF notifications and strand buffered frames.

3 open findings

• Handle setup failure before using uninitialized frameBufferSize
• Abort acquisition when unlocking the oldest frame fails
• Avoid discarding pending frame callbacks during dequeue recovery

🧠 Review effort: Balanced

[Copilot]

🟡 Changes recommended

Concurrent stop/start requests can create overlapping acquisition workers and compromise shared buffer ownership.

4 open findings

• Prevent new acquisitions until the previous worker has joined · New
• Handle setup failure before using uninitialized frameBufferSize
• Abort acquisition when unlocking the oldest frame fails
• Avoid discarding pending frame callbacks during dequeue recovery

🧠 Review effort: Balanced

[Copilot]

🔵 Needs a closer look

Frame-number arithmetic can overflow, and startup failures do not retain an error status.

4 open findings

• Prevent new acquisitions until the previous worker has joined
• Handle setup failure before using uninitialized frameBufferSize
• Abort acquisition when unlocking the oldest frame fails
• Avoid discarding pending frame callbacks during dequeue recovery

Previously missed (2)

In code that hasn't changed since last review

Report allocation failures before publishing acquisition status

kinetixApp/​src/​ADKinetix.cpp:974

When buffer allocation or frame-info creation fails, execution still publishes ADStatusWaiting or ADStatusAcquire, skips the acquisition loop, and ends with ADStatusIdle. This hides the startup failure from status consumers. Clean up and return with ADStatusError before publishing an acquiring status.

Prevent signed overflow at INT32_MAX frame number

kinetixApp/​src/​ADKinetix.cpp:1009

If a continuous acquisition reaches INT32_MAX, the next comparison evaluates lastFrameNr + 1 with signed 32-bit arithmetic, causing undefined behavior. Promote the addition to 64 bits to keep this comparison safe at the frame-number boundary.

🧠 Review effort: Balanced