Struct PluginDescriptor 

#[repr(C)]
pub struct PluginDescriptor {
    pub abi_version: u32,
    pub interface_name: *const c_char,
    pub interface_hash: u64,
    pub interface_version: u32,
    pub capabilities: u64,
    pub wire_format: u8,
    pub buffer_strategy: u8,
    pub plugin_name: *const c_char,
    pub vtable: *const c_void,
    pub free_buffer: Option<unsafe extern "C" fn(*mut u8, usize)>,
    pub method_count: u32,
}

Metadata descriptor for a single plugin within a dylib.

Contains all information the host needs to validate and call the plugin without executing any plugin code. All string fields are pointers to static, null-terminated C strings embedded in the dylib.

Safety

• interface_name and plugin_name must point to valid, null-terminated, UTF-8 C strings with 'static lifetime.
• vtable must point to a valid #[repr(C)] vtable struct matching the interface identified by interface_name and interface_hash.
• When buffer_strategy == PluginAllocated, free_buffer must be Some.
• All pointed-to data must outlive any PluginHandle derived from this descriptor.

Fields

abi_version: u32

Descriptor struct layout version. Must equal ABI_VERSION.

interface_name: *const c_char

Null-terminated name of the trait this plugin implements (e.g., "ImageFilter").

interface_hash: u64

FNV-1a hash of the required method signatures. Detects ABI drift.

interface_version: u32

User-specified interface version from #[plugin_interface(version = N)].

capabilities: u64

Bitfield where bit N indicates optional method N is implemented. Supports up to 64 optional methods per interface.

wire_format: u8

Wire serialization format this plugin was compiled with.

buffer_strategy: u8

Buffer management strategy this plugin’s vtable expects.

plugin_name: *const c_char

Null-terminated human-readable name for this plugin implementation.

vtable: *const c_void

Opaque pointer to the interface-specific #[repr(C)] vtable struct.

free_buffer: Option<unsafe extern "C" fn(*mut u8, usize)>

Deallocation function for plugin-allocated buffers. Must be Some when buffer_strategy == PluginAllocated. The host calls this after reading output data to free the plugin’s allocation.

method_count: u32

Total number of methods in the vtable (required + optional). Used for bounds checking in call_method.

Implementations

impl PluginDescriptor

pub unsafe fn interface_name_str(&self) -> &str

Read the interface_name field as a Rust &str.

Safety

interface_name must point to a valid, null-terminated, UTF-8 C string that outlives the returned reference.

pub unsafe fn plugin_name_str(&self) -> &str

Read the plugin_name field as a Rust &str.

Safety

plugin_name must point to a valid, null-terminated, UTF-8 C string that outlives the returned reference.

pub fn buffer_strategy_kind(&self) -> Result<BufferStrategyKind, u8>

Returns the buffer_strategy field as a BufferStrategyKind.

Returns Err(value) if the discriminant is unknown. This can happen with malformed plugins — callers should reject rather than panic.

pub fn wire_format_kind(&self) -> Result<WireFormat, u8>

Returns the wire_format field as a WireFormat.

Returns Err(value) if the discriminant is unknown.

pub fn has_capability(&self, bit: u32) -> bool

Check if the given optional method capability bit is set.

Returns false for bit indices >= 64 rather than panicking.

Trait Implementations

impl Send for PluginDescriptor

impl Sync for PluginDescriptor