Struct uuid::Uuid

pub struct Uuid { /* fields omitted */ }

A Universally Unique Identifier (UUID).

Methods

impl Uuid

fn nil() -> Uuid

The 'nil UUID'.

The nil UUID is special form of UUID that is specified to have all 128 bits set to zero, as defined in IETF RFC 4122 Section 4.1.7.

Examples

Basic usage:

use uuid::Uuid;

let uuid = Uuid::nil();

assert_eq!(uuid.hyphenated().to_string(),
           "00000000-0000-0000-0000-000000000000");

fn new(v: UuidVersion) -> Option<Uuid>

Creates a new Uuid.

Note that not all versions can be generated currently and None will be returned if the specified version cannot be generated.

To generate a random UUID (UuidVersion::Random), then the v4 feature must be enabled for this crate.

fn new_v1<T: UuidV1ClockSequence>(
    context: &T,
    seconds: u64,
    nsecs: u32,
    node: &[u8]
) -> Result<Uuid, ParseError>

Creates a new Uuid (version 1 style) using a time value + seq + NodeID.

This expects two values representing a monotonically increasing value as well as a unique 6 byte NodeId, and an implementation of UuidV1ClockSequence. This function is only guaranteed to produce unique values if the following conditions hold:

1. The NodeID is unique for this process,
2. The Context is shared across all threads which are generating V1 UUIDs,
3. The UuidV1ClockSequence implementation reliably returns unique clock sequences (this crate provides UuidV1Context for this purpose).

The NodeID must be exactly 6 bytes long. If the NodeID is not a valid length this will return a ParseError::InvalidLength.

The function is not guaranteed to produce monotonically increasing values however. There is a slight possibility that two successive equal time values could be supplied and the sequence counter wraps back over to 0.

If uniqueness and monotonicity is required, the user is responsibile for ensuring that the time value always increases between calls (including between restarts of the process and device).

Note that usage of this method requires the v1 feature of this crate to be enabled.

Examples

Basic usage:

use uuid::{Uuid, UuidV1Context};

let ctx = UuidV1Context::new(42);
let v1uuid = Uuid::new_v1(&ctx, 1497624119, 1234, &[1,2,3,4,5,6]).unwrap();

assert_eq!(v1uuid.hyphenated().to_string(), "f3b4958c-52a1-11e7-802a-010203040506");

fn new_v3(namespace: &Uuid, name: &str) -> Uuid

Creates a UUID using a name from a namespace, based on the MD5 hash.

A number of namespaces are available as constants in this crate:

• NAMESPACE_DNS
• NAMESPACE_URL
• NAMESPACE_OID
• NAMESPACE_X500

Note that usage of this method requires the v3 feature of this crate to be enabled.

fn new_v4() -> Uuid

Creates a random Uuid.

This uses the rand crate's default task RNG as the source of random numbers. If you'd like to use a custom generator, don't use this method: use the rand::Rand trait's rand() method instead.

Note that usage of this method requires the v4 feature of this crate to be enabled.

Examples

Basic usage:

use uuid::Uuid;

let uuid = Uuid::new_v4();

fn new_v5(namespace: &Uuid, name: &str) -> Uuid

Creates a UUID using a name from a namespace, based on the SHA-1 hash.

A number of namespaces are available as constants in this crate:

• NAMESPACE_DNS
• NAMESPACE_URL
• NAMESPACE_OID
• NAMESPACE_X500

Note that usage of this method requires the v5 feature of this crate to be enabled.

fn from_fields(d1: u32, d2: u16, d3: u16, d4: &[u8]) -> Result<Uuid, ParseError>

Creates a Uuid from four field values.

Errors

This function will return an error if d4's length is not 8 bytes.

Examples

Basic usage:

use uuid::Uuid;

let d4 = [12, 3, 9, 56, 54, 43, 8, 9];

let uuid = Uuid::from_fields(42, 12, 5, &d4);
let uuid = uuid.map(|uuid| uuid.hyphenated().to_string());

let expected_uuid = Ok(String::from("0000002a-000c-0005-0c03-0938362b0809"));

assert_eq!(expected_uuid, uuid);

An invalid length:

use uuid::Uuid;
use uuid::ParseError;

let d4 = [12];

let uuid = Uuid::from_fields(42, 12, 5, &d4);

let expected_uuid = Err(ParseError::InvalidLength(1));

assert_eq!(expected_uuid, uuid);

fn from_bytes(b: &[u8]) -> Result<Uuid, ParseError>

Creates a Uuid using the supplied bytes.

Errors

This function will return an error if b has any length other than 16.

Examples

Basic usage:

use uuid::Uuid;

let bytes = [4, 54, 67, 12, 43, 2, 98, 76,
             32, 50, 87, 5, 1, 33, 43, 87];

let uuid = Uuid::from_bytes(&bytes);
let uuid = uuid.map(|uuid| uuid.hyphenated().to_string());

let expected_uuid = Ok(String::from("0436430c-2b02-624c-2032-570501212b57"));

assert_eq!(expected_uuid, uuid);

An incorrect number of bytes:

use uuid::Uuid;
use uuid::ParseError;

let bytes = [4, 54, 67, 12, 43, 2, 98, 76];

let uuid = Uuid::from_bytes(&bytes);

let expected_uuid = Err(ParseError::InvalidLength(8));

assert_eq!(expected_uuid, uuid);

fn from_uuid_bytes(b: UuidBytes) -> Uuid

Creates a Uuid using the supplied bytes.

Examples

Basic usage:

use uuid::Uuid;
use uuid::UuidBytes;

let bytes:UuidBytes = [70, 235, 208, 238, 14, 109, 67, 201, 185, 13, 204, 195, 90, 145, 63, 62];

let uuid = Uuid::from_uuid_bytes(bytes);
let uuid = uuid.hyphenated().to_string();

let expected_uuid = String::from("46ebd0ee-0e6d-43c9-b90d-ccc35a913f3e");

assert_eq!(expected_uuid, uuid);

An incorrect number of bytes:

use uuid::Uuid;
use uuid::UuidBytes;

let bytes:UuidBytes = [4, 54, 67, 12, 43, 2, 98, 76]; // doesn't compile

let uuid = Uuid::from_uuid_bytes(bytes);

fn get_variant(&self) -> Option<UuidVariant>

Returns the variant of the Uuid structure.

This determines the interpretation of the structure of the UUID. Currently only the RFC4122 variant is generated by this module.

• Variant Reference

fn get_version_num(&self) -> usize

Returns the version number of the Uuid.

This represents the algorithm used to generate the contents.

Currently only the Random (V4) algorithm is supported by this module. There are security and privacy implications for using older versions - see Wikipedia: Universally Unique Identifier for details.

• Version Reference

fn get_version(&self) -> Option<UuidVersion>

Returns the version of the Uuid.

This represents the algorithm used to generate the contents

fn as_fields(&self) -> (u32, u16, u16, &[u8; 8])

Returns the four field values of the UUID.

These values can be passed to the from_fields() method to get the original Uuid back.

• The first field value represents the first group of (eight) hex digits, taken as a big-endian u32 value. For V1 UUIDs, this field represents the low 32 bits of the timestamp.
• The second field value represents the second group of (four) hex digits, taken as a big-endian u16 value. For V1 UUIDs, this field represents the middle 16 bits of the timestamp.
• The third field value represents the third group of (four) hex digits, taken as a big-endian u16 value. The 4 most significant bits give the UUID version, and for V1 UUIDs, the last 12 bits represent the high 12 bits of the timestamp.
• The last field value represents the last two groups of four and twelve hex digits, taken in order. The first 1-3 bits of this indicate the UUID variant, and for V1 UUIDs, the next 13-15 bits indicate the clock sequence and the last 48 bits indicate the node ID.

Examples

use uuid::Uuid;

let uuid = Uuid::nil();
assert_eq!(uuid.as_fields(), (0, 0, 0, &[0u8; 8]));

let uuid = Uuid::parse_str("936DA01F-9ABD-4D9D-80C7-02AF85C822A8").unwrap();
assert_eq!(uuid.as_fields(),
           (0x936DA01F, 0x9ABD, 0x4D9D, b"\x80\xC7\x02\xAF\x85\xC8\x22\xA8"));

fn as_bytes(&self) -> &[u8; 16]

Returns an array of 16 octets containing the UUID data.

Examples

use uuid::Uuid;

let uuid = Uuid::nil();
assert_eq!(uuid.as_bytes(), &[0; 16]);

let uuid = Uuid::parse_str("936DA01F9ABD4d9d80C702AF85C822A8").unwrap();
assert_eq!(uuid.as_bytes(),
           &[147, 109, 160, 31, 154, 189, 77, 157,
             128, 199, 2, 175, 133, 200, 34, 168]);

fn simple(&self) -> Simple

Returns a wrapper which when formatted via fmt::Display will format a string of 32 hexadecimal digits.

Examples

use uuid::Uuid;

let uuid = Uuid::nil();
assert_eq!(uuid.simple().to_string(),
           "00000000000000000000000000000000");

fn hyphenated(&self) -> Hyphenated

Returns a wrapper which when formatted via fmt::Display will format a string of hexadecimal digits separated into groups with a hyphen.

Examples

use uuid::Uuid;

let uuid = Uuid::nil();
assert_eq!(uuid.hyphenated().to_string(),
           "00000000-0000-0000-0000-000000000000");

fn urn(&self) -> Urn

Returns a wrapper which when formatted via fmt::Display will format a string of the UUID as a full URN string.

Examples

use uuid::Uuid;

let uuid = Uuid::nil();
assert_eq!(uuid.urn().to_string(),
           "urn:uuid:00000000-0000-0000-0000-000000000000");

fn to_timestamp(&self) -> Option<(u64, u16)>

Returns an Optional Tuple of (u64, u16) representing the timestamp and counter portion of a V1 UUID. If the supplied UUID is not V1, this will return None

fn parse_str(input: &str) -> Result<Uuid, ParseError>

Parses a Uuid from a string of hexadecimal digits with optional hyphens.

Any of the formats generated by this module (simple, hyphenated, urn) are supported by this parsing function.

fn is_nil(&self) -> bool

Tests if the UUID is nil

Trait Implementations

impl Serialize for Uuid

fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error>

Serialize this value into the given Serde serializer.

impl<'de> Deserialize<'de> for Uuid

fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error>

Deserialize this value from the given Serde deserializer.

impl Copy for Uuid

impl Clone for Uuid

fn clone(&self) -> Uuid

Returns a copy of the value.

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

Performs copy-assignment from source.

impl PartialEq for Uuid

fn eq(&self, __arg_0: &Uuid) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, __arg_0: &Uuid) -> bool

This method tests for !=.

impl Eq for Uuid

impl PartialOrd for Uuid

fn partial_cmp(&self, __arg_0: &Uuid) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, __arg_0: &Uuid) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, __arg_0: &Uuid) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, __arg_0: &Uuid) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, __arg_0: &Uuid) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Ord for Uuid

fn cmp(&self, __arg_0: &Uuid) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

impl Default for Uuid

fn default() -> Uuid

Returns the nil UUID, which is all zeroes

impl FromStr for Uuid

type Err = ParseError

The associated error which can be returned from parsing.

fn from_str(us: &str) -> Result<Uuid, ParseError>

Parse a hex string and interpret as a Uuid.

Accepted formats are a sequence of 32 hexadecimal characters, with or without hyphens (grouped as 8, 4, 4, 4, 12).

impl Debug for Uuid

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

Formats the value using the given formatter.

impl Display for Uuid

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

Formats the value using the given formatter.

impl UpperHex for Uuid

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

Formats the value using the given formatter.

impl LowerHex for Uuid

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

Formats the value using the given formatter.

impl Hash for Uuid

fn hash<S: Hasher>(&self, state: &mut S)

Feeds this value into the given [Hasher].

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given [Hasher].

impl Value for Uuid

fn serialize(
    &self,
    _record: &Record,
    key: Key,
    serializer: &mut Serializer
) -> Result<(), Error>

Serialize self into Serializer