Struct sequoia_openpgp::serialize::stream::padding::Padder

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pub struct Padder<'a> { /* private fields */ }
Expand description

Pads a packet stream.

Writes a compressed data packet containing all packets written to this writer, and pads it according to the given policy.

The policy is a Fn(u64) -> u64, that given the number of bytes written to this writer N, computes the size the compression container should be padded up to. It is an error to return a number that is smaller than N.

§Compatibility

This implementation uses the DEFLATE compression format. The packet structure contains a flag signaling the end of the stream (see Section 3.2.3 of RFC 1951), and any data appended after that is not part of the stream.

Section 9.3 of RFC 4880 recommends that this algorithm should be implemented, therefore support across various implementations should be good.

§Examples

This example illustrates the use of Padder with the Padmé policy. Note that for brevity, the encryption and signature filters are omitted.

use std::io::Write;
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::{Message, LiteralWriter};
use openpgp::serialize::stream::padding::Padder;
use openpgp::types::CompressionAlgorithm;

let mut unpadded = vec![];
{
    let message = Message::new(&mut unpadded);
    // XXX: Insert Encryptor here.
    // XXX: Insert Signer here.
    let mut message = LiteralWriter::new(message).build()?;
    message.write_all(b"Hello world.")?;
    message.finalize()?;
}

let mut padded = vec![];
{
    let message = Message::new(&mut padded);
    // XXX: Insert Encryptor here.
    let message = Padder::new(message).build()?;
    // XXX: Insert Signer here.
    let mut message = LiteralWriter::new(message).build()?;
    message.write_all(b"Hello world.")?;
    message.finalize()?;
}
assert!(unpadded.len() < padded.len());

Implementations§

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impl<'a> Padder<'a>

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pub fn new(inner: Message<'a>) -> Self

Creates a new padder with the given policy.

§Examples

This example illustrates the use of Padder with the Padmé policy.

The most useful filter to push to the writer stack next is the Signer or the LiteralWriter. Finally, literal data must be wrapped using the LiteralWriter.

use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::padding::Padder;

let message = Padder::new(message).build()?;
// Optionally add a `Signer` here.
// Add a `LiteralWriter` here.
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pub fn with_policy(self, p: fn(_: u64) -> u64) -> Self

Sets padding policy, returning the padder.

§Examples

This example illustrates the use of Padder with an explicit policy.

use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::padding::{Padder, padme};

let message = Padder::new(message).with_policy(padme).build()?;
// Optionally add a `Signer` here.
// Add a `LiteralWriter` here.
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pub fn build(self) -> Result<Message<'a>>

Builds the padder, returning the writer stack.

§Examples

This example illustrates the use of Padder with the Padmé policy.

The most useful filter to push to the writer stack next is the Signer or the LiteralWriter. Finally, literal data must be wrapped using the LiteralWriter.

use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::padding::Padder;

let message = Padder::new(message).build()?;
// Optionally add a `Signer` here.
// Add a `LiteralWriter` here.

Trait Implementations§

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impl<'a> Debug for Padder<'a>

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

Formats the value using the given formatter. Read more
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impl<'a> Write for Padder<'a>

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fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this writer, returning how many bytes were written. Read more
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fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
1.36.0 · source§

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers. Read more
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fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)
Determines if this Writer has an efficient write_vectored implementation. Read more
1.0.0 · source§

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer. Read more
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fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)
Attempts to write multiple buffers into this writer. Read more
1.0.0 · source§

fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered. Read more
1.0.0 · source§

fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Creates a “by reference” adapter for this instance of Write. Read more

Auto Trait Implementations§

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impl<'a> Freeze for Padder<'a>

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impl<'a> !RefUnwindSafe for Padder<'a>

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impl<'a> Send for Padder<'a>

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impl<'a> Sync for Padder<'a>

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impl<'a> Unpin for Padder<'a>

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impl<'a> !UnwindSafe for Padder<'a>

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.