Class IpcBufferModel

src/host/ui/ipc_buffer_model.h:55–91

Dynamic, IPC-fed BufferModel: buffers are added/replaced/removed at runtime as IpcClient observes them arrive, get re-plotted, or leave. Unlike MockBufferModel's fixed set, this model mutates in place via upsert()/remove(). Storage is vector >, mirroring MockBufferModel, so each live BufferRecord keeps a stable heap address: a Stage holds a std::span into a BufferRecord::b

// revision_of(i) let a consumer detect "something changed" and "which slot
// changed" cheaply, without diffing bytes.
class IpcBufferModel final : public BufferModel {
  public:
    std::size_t size() const override;
    const BufferRecord& at(std::size_t i) const override;

    // Inserts a new buffer, or replaces an existing one matched by
    // `record.variable_name`. On replace, the matching slot's unique_ptr is
    // swapped for a fresh one built from `record` (the old BufferRecord is
    // destroyed), and that slot's per-slot revision advances so consumers
    // can tell a re-plot from an untouched buffer. On insert, the record is
    // appended. Either way, the model-wide revision() advances.
    void upsert(BufferRecord record);

    // Removes the buffer matched by `variable_name`, if any. No-op (and
    // does not bump revision()) if no buffer with that name is present.
    void remove(std::string_view variable_name);

    // Monotonic counter bumped on every upsert/remove, for cheap
    // model-wide change detection.
    [[nodiscard]] std::uint64_t revision() const {
        return revision_;
    }

    // Per-slot revision, bumped only when that slot's BufferRecord is
    // replaced (insert or re-plot), so a consumer can tell a re-plot of
    // buffer i from an unrelated change elsewhere in the model.
    [[nodiscard]] std::uint64_t revision_of(std::size_t i) const override;

    [[nodiscard]] const std::string&
    variable_name_of(std::size_t i) const override;

  private:
    std::vector<std::unique_ptr<BufferRecord>> storage_;
    std::vector<std::uint64_t> slot_revision_; // parallel to storage_
    std::uint64_t revision_{0};
    std::uint64_t next_slot_rev_{1};
};

} // namespace oid::host