Struct FFI_ArrowSchema

Source

#[repr(C)]pub struct FFI_ArrowSchema {
    format: *const c_char,
    name: *const c_char,
    metadata: *const c_char,
    flags: i64,
    n_children: i64,
    children: *mut *mut FFI_ArrowSchema,
    dictionary: *mut FFI_ArrowSchema,
    release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowSchema)>,
    private_data: *mut c_void,
}

Expand description

ABI-compatible struct for ArrowSchema from C Data Interface See https://arrow.apache.org/docs/format/CDataInterface.html#the-arrowschema-structure

fn array_schema(data_type: &DataType) -> FFI_ArrowSchema {
    FFI_ArrowSchema::try_from(data_type).unwrap()
}

Fields§

§format: *const c_char

Null-terminated, UTF8-encoded string describing the data type

§name: *const c_char

Null-terminated, UTF8-encoded string of the field or array name

§metadata: *const c_char

Binary string describing the type’s metadata

§flags: i64

A bitfield of flags enriching the type description Refer to Arrow Flags

§n_children: i64

The number of children this type has

§children: *mut *mut FFI_ArrowSchema

C array of pointers to each child type of this type

§dictionary: *mut FFI_ArrowSchema

Pointer to the type of dictionary values

§release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowSchema)>

Producer-provided release callback.

§private_data: *mut c_void

Opaque producer-provided private data, owned by the release callback.

Implementations§

Source §

impl FFI_ArrowSchema

Source

pub fn try_new( format: &str, children: Vec<FFI_ArrowSchema>, dictionary: Option<FFI_ArrowSchema>, ) -> Result<Self, ArrowError>

create a new FFI_ArrowSchema. This fails if the fields’ DataType is not supported.

§Panics

Panics if format contains an interior nul byte

Source

pub fn with_name(self, name: &str) -> Result<Self, ArrowError>

Set the name of the schema

Source

pub fn with_flags(self, flags: Flags) -> Result<Self, ArrowError>

Set the flags of the schema

Source

pub fn with_metadata<I, S>(self, metadata: I) -> Result<Self, ArrowError>
where I: IntoIterator<Item = (S, S)>, S: AsRef<str>,

Add metadata to the schema

Source

pub unsafe fn from_raw(schema: *mut FFI_ArrowSchema) -> Self

Takes ownership of the pointed to FFI_ArrowSchema

This acts to move the data out of schema, setting the release callback to NULL

§Safety

schema must be valid for reads and writes
schema must be properly aligned
schema must point to a properly initialized value of FFI_ArrowSchema

Source

pub fn empty() -> Self

Create an empty FFI_ArrowSchema

Source

pub fn release( &self, ) -> Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowSchema)>

Returns the producer-provided release callback, if any.

Source

pub fn private_data(&self) -> *mut c_void

Returns the opaque producer-provided private data pointer.

Source

pub unsafe fn set_release( &mut self, release: Option<unsafe extern "C" fn(arg1: mut FFI_ArrowSchema)>, ) -> Option<unsafe extern "C" fn(arg1: mut FFI_ArrowSchema)>

Replaces the release callback, returning the previous one.

Lets a consumer wrap release: save the old callback, install its own, and chain back on drop. See https://github.com/apache/arrow-rs/issues/9771.

§Safety

Drop calls this callback with a pointer to self. The new callback must correctly release this schema (usually by chaining to the returned one) and must match the FFI_ArrowSchema::private_data it reads. A wrong callback is undefined behavior on drop.

Source

pub unsafe fn set_private_data( &mut self, private_data: mut c_void, ) -> mut c_void

Replaces the private data pointer, returning the previous one.

§Safety

The old pointer is returned without being freed; the caller owns it from here. The new pointer must match what the current FFI_ArrowSchema::release callback expects.

Source