Struct Metadata

pub struct Metadata {

    pub version: u8,
    pub dataset: String,
    pub schema: Option<Schema>,
    pub start: u64,
    pub end: Option<NonZeroU64>,
    pub limit: Option<NonZeroU64>,
    pub stype_in: Option<SType>,
    pub stype_out: SType,
    pub ts_out: bool,
    pub symbol_cstr_len: usize,
    pub symbols: Vec<String>,
    pub partial: Vec<String>,
    pub not_found: Vec<String>,
    pub mappings: Vec<SymbolMapping>,
}

Information about the data contained in a DBN file or stream. DBN requires the Metadata to be included at the start of the encoded data.

Fields

version: u8

The DBN schema version number. Newly-encoded DBN files will use crate::DBN_VERSION.

dataset: String

The dataset code.

schema: Option<Schema>

The data record schema. Specifies which record types are in the DBN stream. None indicates the DBN stream may contain more than one record type.

start: u64

The UNIX nanosecond timestamp of the query start, or the first record if the file was split.

end: Option<NonZeroU64>

The UNIX nanosecond timestamp of the query end, or the last record if the file was split.

limit: Option<NonZeroU64>

The optional maximum number of records for the query.

stype_in: Option<SType>

The input symbology type to map from. None indicates a mix, such as in the case of live data.

stype_out: SType

The output symbology type to map to.

ts_out: bool

true if this store contains live data with send timestamps appended to each record.

symbol_cstr_len: usize

The length in bytes of fixed-length symbol strings, including a null terminator byte.

symbols: Vec<String>

The original query input symbols from the request.

partial: Vec<String>

Symbols that did not resolve for at least one day in the query time range.

not_found: Vec<String>

Symbols that did not resolve for any day in the query time range.

mappings: Vec<SymbolMapping>

Symbol mappings containing a raw symbol and its mapping intervals.

Implementations

impl Metadata

pub fn builder() -> MetadataBuilder<Unset, Unset, Unset, Unset, Unset>

Creates a builder for building Metadata. Call .dataset(...), .schema(...), .start(...) .stype_in(...), and .stype_out(...) on the builder to set the required fields. Finally call .build() to create the Metadata instance.

pub fn start(&self) -> OffsetDateTime

Parses the raw query start into a datetime.

pub fn end(&self) -> Option<OffsetDateTime>

Parses the raw query end time or the timestamp of the last record into a datetime. Returns None if the end time was not specified.

pub fn symbol_map_for_date(&self, date: Date) -> Result<PitSymbolMap>

Creates a symbology mapping from instrument ID to text symbol for the given date.

This method is useful when working with a historical request over a single day or in other situations where you’re sure the mappings don’t change during the time range of the request. Otherwise, Self::symbol_map() is recommmended.

Errors

This function returns an error if stype_out is not SType::InstrumentId or it can’t parse a symbol into a u32 instrument ID. It will also return an error if date is outside the query range.

pub fn symbol_map(&self) -> Result<TsSymbolMap>

Creates a symbology mapping from instrument ID and date to text symbol.

If you’re working with a single date or otherwise don’t expect the mappings to change, Self::symbol_map_for_date() is recommended.

Errors

This function returns an error if stype_out is not SType::InstrumentId or it can’t parse a symbol into a u32 instrument ID.

pub fn upgrade(&mut self, upgrade_policy: VersionUpgradePolicy)

Upgrades the metadata according to upgrade_policy if necessary.

pub fn merge(self, other: impl IntoIterator<Item = Metadata>) -> Result<Self>

Attempts to merge another metadata into this one. This is useful for merging DBN streams.

If merging data from multiple schemas, the resulting metadata will have a schema of None.

Errors

Merging metadata where any of the following fields don’t match will result in an error:

• version: upgrade the metadata of the lower version before merging
• dataset
• stype_in
• stype_out
• ts_out
• symbol_cstr_len: upgrade the metadata of the lower version before merging

This function will also return an error if there are conflicting symbology mappings.

Trait Implementations

impl AsRef<[u8]> for Metadata

fn as_ref(&self) -> &[u8]

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for Metadata

fn clone(&self) -> Metadata

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Metadata

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'py> IntoPyObject<'py> for Metadata

type Target = Metadata

The Python output type

type Output = Bound<'py, <Metadata as IntoPyObject<'py>>::Target>

The smart pointer type to use.

type Error = PyErr

The type returned in the event of a conversion error.

fn into_pyobject( self, py: Python<'py>, ) -> Result<<Self as IntoPyObject<'_>>::Output, <Self as IntoPyObject<'_>>::Error>

Performs the conversion.

impl PartialEq for Metadata

fn eq(&self, other: &Metadata) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PyClass for Metadata

type Frozen = False

Whether the pyclass is frozen.

impl PyClassImpl for Metadata

const IS_BASETYPE: bool = false

#[pyclass(subclass)]

const IS_SUBCLASS: bool = false

#[pyclass(extends=…)]

const IS_MAPPING: bool = false

#[pyclass(mapping)]

const IS_SEQUENCE: bool = false

#[pyclass(sequence)]

const IS_IMMUTABLE_TYPE: bool = false

#[pyclass(immutable_type)]

type BaseType = PyAny

Base class

type ThreadChecker = SendablePyClass<Metadata>

This handles following two situations:

type PyClassMutability = <<PyAny as PyClassBaseType>::PyClassMutability as PyClassMutability>::MutableChild

Immutable or mutable

type Dict = PyClassDummySlot

Specify this class has #[pyclass(dict)] or not.

type WeakRef = PyClassDummySlot

Specify this class has #[pyclass(weakref)] or not.

type BaseNativeType = PyAny

The closest native ancestor. This is PyAny by default, and when you declare #[pyclass(extends=PyDict)], it’s PyDict.

fn items_iter() -> PyClassItemsIter

fn doc(py: Python<'_>) -> PyResult<&'static CStr>

Rendered class doc

fn lazy_type_object() -> &'static LazyTypeObject<Self>

fn dict_offset() -> Option<isize>

fn weaklist_offset() -> Option<isize>

impl PyClassNewTextSignature<Metadata> for PyClassImplCollector<Metadata>

Available on crate feature python only.

fn new_text_signature(self) -> Option<&'static str>

impl<'a, 'py> PyFunctionArgument<'a, 'py, false> for &'a Metadata

type Holder = Option<PyRef<'py, Metadata>>

fn extract( obj: &'a Bound<'py, PyAny>, holder: &'a mut Self::Holder, ) -> PyResult<Self>

impl<'a, 'py> PyFunctionArgument<'a, 'py, false> for &'a mut Metadata

type Holder = Option<PyRefMut<'py, Metadata>>

fn extract( obj: &'a Bound<'py, PyAny>, holder: &'a mut Self::Holder, ) -> PyResult<Self>

impl PyMethods<Metadata> for PyClassImplCollector<Metadata>

Available on crate feature python only.

fn py_methods(self) -> &'static PyClassItems

impl PyTypeInfo for Metadata

const NAME: &'static str = "Metadata"

Class name.

const MODULE: Option<&'static str>

Module name, if any.

fn type_object_raw(py: Python<'_>) -> *mut PyTypeObject

Returns the PyTypeObject instance for this type.

fn type_object(py: Python<'_>) -> Bound<'_, PyType>

Returns the safe abstraction over the type object.

fn is_type_of(object: &Bound<'_, PyAny>) -> bool

Checks if object is an instance of this type or a subclass of this type.

fn is_exact_type_of(object: &Bound<'_, PyAny>) -> bool

Checks if object is an instance of this type.

impl TryFrom<&Metadata> for TsSymbolMap

type Error = Error

The type returned in the event of a conversion error.

fn try_from(metadata: &Metadata) -> Result<Self, Error>

Performs the conversion.

impl DerefToPyAny for Metadata

impl Eq for Metadata

impl StructuralPartialEq for Metadata