Enum timely::dataflow::channels::message::Content

pub enum Content<D> {
    Bytes(Vec<u8>, usize, usize),
    Typed(Vec<D>),
}

A batch of data, represented either as serialized bytes or typed Rust objects.

Variants

Bytes(Vec<u8>, usize, usize)

A serialized representation of data.

This representation may be efficiently observed as shared references, but may only more expensively be converted into typed data.

Typed(Vec<D>)

Typed data, which may be efficiently mutated or claimed for ownership.

Methods

impl<D> Content<D>

fn take(&mut self) -> Content<D>

Gives ownership of the content, leaving an empty vector behind.

fn default_length() -> usize

Default number of elements in a typed allocated message. This could vary as a function of std::mem::size_of::<D>(), so is left as a method rather than a constant.

fn len(&self) -> usize

The length of the underlying typed vector.

The length is tracked without needing to deserialize the data, so that this method can be called even for D that do not implement Serializable.

fn from_typed(typed: &mut Vec<D>) -> Content<D>

Constructs a Message from typed data, replacing its argument with Vec::new().

fn into_typed(self) -> Vec<D>

Returns the typed vector, cleared, or a Vec::new() if the data are binary (and drops them on the floor, I guess! Ouch. ALLOC : dropping of binary data. likely called only by persons who pushed typed data on, ALLOC : so perhaps not all that common. Could put a panic! here just for fun! :D ALLOC : casual dropping of contents of data, which might have allocated memory.

fn push_at<T, P: Push<(T, Content<D>)>>(buffer: &mut Vec<D>, time: T, pusher: &mut P)

Pushes buffer into pusher, ensuring that buffer remains valid once returned.

impl<D: Clone + Abomonation> Content<D>

fn replace_with(&mut self, other: Vec<D>) -> Vec<D>

Swaps the contents with another vector.

This method is a convenient way to take ownership of the underlying data without needing to import the DerefMut trait and write horrible gunk.

Methods from Deref<Target=Vec<D>>

fn capacity(&self) -> usize

Returns the number of elements the vector can hold without reallocating.

Examples

let vec: Vec<i32> = Vec::with_capacity(10);
assert_eq!(vec.capacity(), 10);

fn reserve(&mut self, additional: usize)

Reserves capacity for at least additional more elements to be inserted in the given Vec<T>. The collection may reserve more space to avoid frequent reallocations.

Panics

Panics if the new capacity overflows usize.

Examples

let mut vec = vec![1];
vec.reserve(10);
assert!(vec.capacity() >= 11);

fn reserve_exact(&mut self, additional: usize)

Reserves the minimum capacity for exactly additional more elements to be inserted in the given Vec<T>. Does nothing if the capacity is already sufficient.

Note that the allocator may give the collection more space than it requests. Therefore capacity can not be relied upon to be precisely minimal. Prefer reserve if future insertions are expected.

Panics

Panics if the new capacity overflows usize.

Examples

let mut vec = vec![1];
vec.reserve_exact(10);
assert!(vec.capacity() >= 11);

fn shrink_to_fit(&mut self)

Shrinks the capacity of the vector as much as possible.

It will drop down as close as possible to the length but the allocator may still inform the vector that there is space for a few more elements.

Examples

let mut vec = Vec::with_capacity(10);
vec.extend([1, 2, 3].iter().cloned());
assert_eq!(vec.capacity(), 10);
vec.shrink_to_fit();
assert!(vec.capacity() >= 3);

fn into_boxed_slice(self) -> Box<[T]>

Converts the vector into Box<[T]>.

Note that this will drop any excess capacity. Calling this and converting back to a vector with into_vec() is equivalent to calling shrink_to_fit().

fn truncate(&mut self, len: usize)

Shortens the vector, keeping the first len elements and dropping the rest.

If len is greater than the vector's current length, this has no effect.

The drain method can emulate truncate, but causes the excess elements to be returned instead of dropped.

Examples

Truncating a five element vector to two elements:

let mut vec = vec![1, 2, 3, 4, 5];
vec.truncate(2);
assert_eq!(vec, [1, 2]);

No truncation occurs when len is greater than the vector's current length:

let mut vec = vec![1, 2, 3];
vec.truncate(8);
assert_eq!(vec, [1, 2, 3]);

Truncating when len == 0 is equivalent to calling the clear method.

let mut vec = vec![1, 2, 3];
vec.truncate(0);
assert_eq!(vec, []);

fn as_slice(&self) -> &[T]

Extracts a slice containing the entire vector.

Equivalent to &s[..].

Examples

use std::io::{self, Write};
let buffer = vec![1, 2, 3, 5, 8];
io::sink().write(buffer.as_slice()).unwrap();

fn as_mut_slice(&mut self) -> &mut [T]

Extracts a mutable slice of the entire vector.

Equivalent to &mut s[..].

Examples

use std::io::{self, Read};
let mut buffer = vec![0; 3];
io::repeat(0b101).read_exact(buffer.as_mut_slice()).unwrap();

unsafe fn set_len(&mut self, len: usize)

Sets the length of a vector.

This will explicitly set the size of the vector, without actually modifying its buffers, so it is up to the caller to ensure that the vector is actually the specified size.

Examples

use std::ptr;

let mut vec = vec!['r', 'u', 's', 't'];

unsafe {
    ptr::drop_in_place(&mut vec[3]);
    vec.set_len(3);
}
assert_eq!(vec, ['r', 'u', 's']);

In this example, there is a memory leak since the memory locations owned by the inner vectors were not freed prior to the set_len call:

let mut vec = vec![vec![1, 0, 0],
                   vec![0, 1, 0],
                   vec![0, 0, 1]];
unsafe {
    vec.set_len(0);
}

In this example, the vector gets expanded from zero to four items without any memory allocations occurring, resulting in vector values of unallocated memory:

let mut vec: Vec<char> = Vec::new();

unsafe {
    vec.set_len(4);
}

fn swap_remove(&mut self, index: usize) -> T

Removes an element from anywhere in the vector and return it, replacing it with the last element.

This does not preserve ordering, but is O(1).

Panics

Panics if index is out of bounds.

Examples

let mut v = vec!["foo", "bar", "baz", "qux"];

assert_eq!(v.swap_remove(1), "bar");
assert_eq!(v, ["foo", "qux", "baz"]);

assert_eq!(v.swap_remove(0), "foo");
assert_eq!(v, ["baz", "qux"]);

fn insert(&mut self, index: usize, element: T)

Inserts an element at position index within the vector, shifting all elements after it to the right.

Panics

Panics if index is greater than the vector's length.

Examples

let mut vec = vec![1, 2, 3];
vec.insert(1, 4);
assert_eq!(vec, [1, 4, 2, 3]);
vec.insert(4, 5);
assert_eq!(vec, [1, 4, 2, 3, 5]);

fn remove(&mut self, index: usize) -> T

Removes and returns the element at position index within the vector, shifting all elements after it to the left.

Panics

Panics if index is out of bounds.

Examples

let mut v = vec![1, 2, 3];
assert_eq!(v.remove(1), 2);
assert_eq!(v, [1, 3]);

fn retain<F>(&mut self, f: F) where F: FnMut(&T) -> bool

Retains only the elements specified by the predicate.

In other words, remove all elements e such that f(&e) returns false. This method operates in place and preserves the order of the retained elements.

Examples

let mut vec = vec![1, 2, 3, 4];
vec.retain(|&x| x%2 == 0);
assert_eq!(vec, [2, 4]);

fn push(&mut self, value: T)

Appends an element to the back of a collection.

Panics

Panics if the number of elements in the vector overflows a usize.

Examples

let mut vec = vec![1, 2];
vec.push(3);
assert_eq!(vec, [1, 2, 3]);

fn pop(&mut self) -> Option<T>

Removes the last element from a vector and returns it, or None if it is empty.

Examples

let mut vec = vec![1, 2, 3];
assert_eq!(vec.pop(), Some(3));
assert_eq!(vec, [1, 2]);

fn append(&mut self, other: &mut Vec<T>)

Moves all the elements of other into Self, leaving other empty.

Panics

Panics if the number of elements in the vector overflows a usize.

Examples

let mut vec = vec![1, 2, 3];
let mut vec2 = vec![4, 5, 6];
vec.append(&mut vec2);
assert_eq!(vec, [1, 2, 3, 4, 5, 6]);
assert_eq!(vec2, []);

fn drain<R>(&mut self, range: R) -> Drain<T> where R: RangeArgument<usize>

Create a draining iterator that removes the specified range in the vector and yields the removed items.

Note 1: The element range is removed even if the iterator is not consumed until the end.

Note 2: It is unspecified how many elements are removed from the vector, if the Drain value is leaked.

Panics

Panics if the starting point is greater than the end point or if the end point is greater than the length of the vector.

Examples

let mut v = vec![1, 2, 3];
let u: Vec<_> = v.drain(1..).collect();
assert_eq!(v, &[1]);
assert_eq!(u, &[2, 3]);

// A full range clears the vector
v.drain(..);
assert_eq!(v, &[]);

fn clear(&mut self)

Clears the vector, removing all values.

Examples

let mut v = vec![1, 2, 3];

v.clear();

assert!(v.is_empty());

fn len(&self) -> usize

Returns the number of elements in the vector.

Examples

let a = vec![1, 2, 3];
assert_eq!(a.len(), 3);

fn is_empty(&self) -> bool

Returns true if the vector contains no elements.

Examples

let mut v = Vec::new();
assert!(v.is_empty());

v.push(1);
assert!(!v.is_empty());

fn split_off(&mut self, at: usize) -> Vec<T>

Splits the collection into two at the given index.

Returns a newly allocated Self. self contains elements [0, at), and the returned Self contains elements [at, len).

Note that the capacity of self does not change.

Panics

Panics if at > len.

Examples

let mut vec = vec![1,2,3];
let vec2 = vec.split_off(1);
assert_eq!(vec, [1]);
assert_eq!(vec2, [2, 3]);

fn resize(&mut self, new_len: usize, value: T)

Resizes the Vec in-place so that len() is equal to new_len.

If new_len is greater than len(), the Vec is extended by the difference, with each additional slot filled with value. If new_len is less than len(), the Vec is simply truncated.

Examples

let mut vec = vec!["hello"];
vec.resize(3, "world");
assert_eq!(vec, ["hello", "world", "world"]);

let mut vec = vec![1, 2, 3, 4];
vec.resize(2, 0);
assert_eq!(vec, [1, 2]);

fn extend_from_slice(&mut self, other: &[T])

Clones and appends all elements in a slice to the Vec.

Iterates over the slice other, clones each element, and then appends it to this Vec. The other vector is traversed in-order.

Note that this function is same as extend except that it is specialized to work with slices instead. If and when Rust gets specialization this function will likely be deprecated (but still available).

Examples

let mut vec = vec![1];
vec.extend_from_slice(&[2, 3, 4]);
assert_eq!(vec, [1, 2, 3, 4]);

fn dedup(&mut self)

Removes consecutive repeated elements in the vector.

If the vector is sorted, this removes all duplicates.

Examples

let mut vec = vec![1, 2, 2, 3, 2];

vec.dedup();

assert_eq!(vec, [1, 2, 3, 2]);

Trait Implementations

impl<D: Clone> Clone for Content<D>

fn clone(&self) -> Content<D>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<D: Abomonation> Deref for Content<D>

type Target = Vec<D>

The resulting type after dereferencing

fn deref(&self) -> &Vec<D>

The method called to dereference a value

impl<D: Clone + Abomonation> DerefMut for Content<D>

fn deref_mut(&mut self) -> &mut Vec<D>

The method called to mutably dereference a value