Struct httpbis::solicit::WindowSize

pub struct WindowSize(pub i32);

The struct represents the size of a flow control window.

It exposes methods that allow the manipulation of window sizes, such that they can never overflow the spec-mandated upper bound.

Methods

impl WindowSize

pub fn try_increase(&mut self, delta: u32) -> Result<(), ()>

Tries to increase the window size by the given delta. If the WindowSize would overflow the maximum allowed value (2^31 - 1), returns an error case. If the increase succeeds, returns Ok.

Examples

use httpbis::solicit::WindowSize;

let mut window_size = WindowSize::new(65_535);
assert_eq!(window_size.size(), 65_535);
// An increase within the bounds...
assert!(window_size.try_increase(100).is_ok());
assert_eq!(window_size.size(), 65_635);
// An increase that would overflow
assert!(window_size.try_increase(0x7fffffff).is_err());
assert_eq!(window_size.size(), 65_635);

pub fn try_decrease(&mut self, delta: i32) -> Result<(), ()>

Tries to decrease the size of the window by the given delta.

There are situations where the window size should legitimately be allowed to become negative, so the only situation where the result is an error is if the window size would underflow, as this would definitely cause the peers to lose sync.

Example

use httpbis::solicit::WindowSize;

let mut window_size = WindowSize::new(65_535);
assert_eq!(window_size.size(), 65_535);
// A decrease...
assert!(window_size.try_decrease(100).is_ok());
assert_eq!(window_size.size(), 65_435);
// A decrease that does not underflow
assert!(window_size.try_decrease(0x7fffffff).is_ok());
assert_eq!(window_size.size(), -2147418212);
// A decrease that *would* underflow
assert!(window_size.try_decrease(0x7fffffff).is_err());
assert_eq!(window_size.size(), -2147418212);

pub fn try_decrease_to_positive(&mut self, delta: i32) -> Result<(), ()>

pub fn new(size: i32) -> WindowSize

Creates a new WindowSize with the given initial size.

pub fn size(&self) -> i32

Returns the current size of the window.

The size is actually allowed to become negative (for instance if the peer changes its intial window size in the settings); therefore, the return is an i32.

Trait Implementations

impl Debug for WindowSize

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

Formats the value using the given formatter.

impl Copy for WindowSize

impl Clone for WindowSize

fn clone(&self) -> WindowSize

Returns a copy of the value.

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

Performs copy-assignment from source.

impl PartialEq for WindowSize

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

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

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

This method tests for !=.

impl Display for WindowSize

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

Formats the value using the given formatter.