Struct thl::ParameterRecord

struct ParameterRecord

Collaboration diagram for thl::ParameterRecord:

Consolidated per-parameter storage.

Each parameter gets one heap-allocated ParameterRecord, owned by State::m_storage via unique_ptr. The record holds everything about the parameter: immutable definition (type, range, flags, name, etc.), atomic cache for real-time value access, gesture state, and string value.

Fields are ordered for cache efficiency. m_cache is at offset 0 so that ParameterHandle::load() touches the first cache line of the allocation. alignas(64) on m_def guarantees the hot cache line contains only m_cache (24 B), isolating it from non-RT writes to m_in_gesture / m_string_value (false-sharing prevention).

Cache-Line Layout

m_key is a string_view pointing into the owning std::map node’s key. Set once after map insertion, never modified. Zero-cost, no duplication.

m_def is const — the definition is immutable after construction. RCU publish in create() provides the happens-before guarantee — readers only see the record after m_key and m_def are fully initialized.

Because AtomicCacheEntry is non-copyable/non-movable the record itself is non-copyable/non-movable — always accessed via pointer.

Public Functions

inline explicit ParameterRecord(ParameterDefinition def)

ParameterRecord(const ParameterRecord&) = delete

ParameterRecord &operator=(const ParameterRecord&) = delete

Public Members

AtomicCacheEntry m_cache

RT-hot: per-sample lock-free access (offset 0 for single cache line fetch)

const ParameterDefinition m_def

Immutable definition (type, range, flags, name, etc.) alignas(64) ensures m_cache occupies its own cache line.

std::string_view m_key

Identity (set once after map insertion, never modified)

std::atomic<bool> m_in_gesture = {false}

Mutable runtime state (non-RT only, separate cache line from m_cache)

std::string m_string_value