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Message

Struct Message 

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pub struct Message<'a>(/* private fields */);
Expand description

Streams an OpenPGP message.

Wraps an io::Writer for use with the streaming subsystem. The Message is a stack of filters that create the desired message structure. Literal data must be framed using the LiteralWriter filter. Once all the has been written, the Message must be finalized using Message::finalize.

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impl<'a> Message<'a>

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pub fn new<W>(w: W) -> Message<'a> ⓘ
where W: 'a + Write + Send + Sync,

Starts streaming an OpenPGP message.

§Examples
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::{Message, LiteralWriter};

let message = Message::new(&mut sink);
// Construct the writer stack here.
let mut message = LiteralWriter::new(message).build()?;
// Write literal data to `message` here.
// ...
// Finalize the message.
message.finalize()?;
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pub fn finalize_one(self) -> Result<Option<Message<'a>>, Error>

Finalizes the topmost writer, returning the underlying writer.

Finalizes the topmost writer, i.e. flushes any buffered data, and pops it of the stack. This allows for fine-grained control of the resulting message, but must be done with great care. If done improperly, the resulting message may be malformed.

§Examples

This demonstrates how to create a compressed, signed message from a detached signature.

use std::io::Write;
use std::convert::TryFrom;
use sequoia_openpgp as openpgp;
use openpgp::packet::{Packet, Signature, one_pass_sig::OnePassSig3};
use openpgp::serialize::Serialize;
use openpgp::serialize::stream::{Message, Compressor, LiteralWriter};

let data: &[u8] = // ...
let sig: Signature = // ...

let message = Message::new(&mut sink);
let mut message = Compressor::new(message).build()?;

// First, write a one-pass-signature packet.
Packet::from(OnePassSig3::try_from(&sig)?)
    .serialize(&mut message)?;

// Then, add the literal data.
let mut message = LiteralWriter::new(message).build()?;
message.write_all(data)?;

// Finally, pop the `LiteralWriter` off the stack to write the
// signature.
let mut message = message.finalize_one()?.unwrap();
Packet::from(sig).serialize(&mut message)?;

// Finalize the message.
message.finalize()?;
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pub fn finalize(self) -> Result<(), Error>

Finalizes the message.

Finalizes all writers on the stack, flushing any buffered data.

§Note

Failing to finalize the message may result in corrupted messages.

§Examples
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::{Message, LiteralWriter};

let message = Message::new(&mut sink);
// Construct the writer stack here.
let mut message = LiteralWriter::new(message).build()?;
// Write literal data to `message` here.
// ...
// Finalize the message.
message.finalize()?;

Trait Implementations§

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impl<'a> Debug for Message<'a>

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

Formats the value using the given formatter. Read more
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impl<'a> From<&'a mut (dyn Write + Send + Sync)> for Message<'a>

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fn from(w: &'a mut (dyn Write + Send + Sync)) -> Message<'a> ⓘ

Converts to this type from the input type.
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impl<'a> Write for Message<'a>

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

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

Flushes 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, args: 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> !RefUnwindSafe for Message<'a>

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

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impl<'a> Freeze for Message<'a>

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impl<'a> Send for Message<'a>

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impl<'a> Sync for Message<'a>

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impl<'a> Unpin for Message<'a>

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impl<'a> UnsafeUnpin for Message<'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<W> ElfWrite for W
where W: Write + ?Sized,

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

Write all bytes. Read more
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fn write_u8(&mut self, value: u8) -> Result<(), Error>

Write one byte as u8.
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fn write_i8(&mut self, value: i8) -> Result<(), Error>

Write one byte as i8.
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fn write_u16(&mut self, byte_order: ByteOrder, value: u16) -> Result<(), Error>

Write u16.
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fn write_u32(&mut self, byte_order: ByteOrder, value: u32) -> Result<(), Error>

Write u32.
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fn write_u64(&mut self, byte_order: ByteOrder, value: u64) -> Result<(), Error>

Write u64.
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fn write_i16(&mut self, byte_order: ByteOrder, value: i16) -> Result<(), Error>

Write i16.
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fn write_i32(&mut self, byte_order: ByteOrder, value: i32) -> Result<(), Error>

Write i32.
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fn write_i64(&mut self, byte_order: ByteOrder, value: i64) -> Result<(), Error>

Write i64.
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fn write_word( &mut self, class: Class, byte_order: ByteOrder, value: u64, ) -> Result<(), Error>

Write one word. Read more
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fn write_word_as_u32( &mut self, class: Class, byte_order: ByteOrder, value: u32, ) -> Result<(), Error>

Write a word specified by value.
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fn write_u32_as_u64( &mut self, byte_order: ByteOrder, value: u64, ) -> Result<(), Error>

Write value as u64.
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fn write_i32_as_i64( &mut self, byte_order: ByteOrder, value: i64, ) -> Result<(), Error>

Write value as i32.
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impl<T> ExecutableCommand for T
where T: Write + ?Sized,

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fn execute(&mut self, command: impl Command) -> Result<&mut T, Error>

Executes the given command directly.

The given command its ANSI escape code will be written and flushed onto Self.

§Arguments
  • Command

    The command that you want to execute directly.

§Example
use std::io;
use crossterm::{ExecutableCommand, style::Print};

fn main() -> io::Result<()> {
     // will be executed directly
      io::stdout()
        .execute(Print("sum:\n".to_string()))?
        .execute(Print(format!("1 + 1= {} ", 1 + 1)))?;

      Ok(())

     // ==== Output ====
     // sum:
     // 1 + 1 = 2
}

Have a look over at the Command API for more details.

§Notes
  • In the case of UNIX and Windows 10, ANSI codes are written to the given ‘writer’.
  • In case of Windows versions lower than 10, a direct WinAPI call will be made. The reason for this is that Windows versions lower than 10 do not support ANSI codes, and can therefore not be written to the given writer. Therefore, there is no difference between execute and queue for those old Windows versions.
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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> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self> ⓘ

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self> ⓘ

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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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> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self> ⓘ

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self> ⓘ
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> MaybeSend for T

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impl<T> MaybeSync for T

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impl<T> Pointable for T

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const ALIGN: usize

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> PolicyExt for T
where T: ?Sized,

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fn and<P, B, E>(self, other: P) -> And<T, P>
where T: Sized + Policy<B, E>, P: Policy<B, E>,

Create a new Policy that returns Action::Follow only if self and other return Action::Follow. Read more
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fn or<P, B, E>(self, other: P) -> Or<T, P>
where T: Sized + Policy<B, E>, P: Policy<B, E>,

Create a new Policy that returns Action::Follow if either self or other returns Action::Follow. Read more
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impl<T> QueueableCommand for T
where T: Write + ?Sized,

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fn queue(&mut self, command: impl Command) -> Result<&mut T, Error>

Queues the given command for further execution.

Queued commands will be executed in the following cases:

  • When flush is called manually on the given type implementing io::Write.
  • The terminal will flush automatically if the buffer is full.
  • Each line is flushed in case of stdout, because it is line buffered.
§Arguments
  • Command

    The command that you want to queue for later execution.

§Examples
use std::io::{self, Write};
use crossterm::{QueueableCommand, style::Print};

 fn main() -> io::Result<()> {
    let mut stdout = io::stdout();

    // `Print` will executed executed when `flush` is called.
    stdout
        .queue(Print("foo 1\n".to_string()))?
        .queue(Print("foo 2".to_string()))?;

    // some other code (no execution happening here) ...

    // when calling `flush` on `stdout`, all commands will be written to the stdout and therefore executed.
    stdout.flush()?;

    Ok(())

    // ==== Output ====
    // foo 1
    // foo 2
}

Have a look over at the Command API for more details.

§Notes
  • In the case of UNIX and Windows 10, ANSI codes are written to the given ‘writer’.
  • In case of Windows versions lower than 10, a direct WinAPI call will be made. The reason for this is that Windows versions lower than 10 do not support ANSI codes, and can therefore not be written to the given writer. Therefore, there is no difference between execute and queue for those old Windows versions.
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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<W> SynchronizedUpdate for W
where W: Write + ?Sized,

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fn sync_update<T>( &mut self, operations: impl FnOnce(&mut W) -> T, ) -> Result<T, Error>

Performs a set of actions within a synchronous update.

Updates will be suspended in the terminal, the function will be executed against self, updates will be resumed, and a flush will be performed.

§Arguments
  • Function

    A function that performs the operations that must execute in a synchronized update.

§Examples
use std::io;
use crossterm::{ExecutableCommand, SynchronizedUpdate, style::Print};

fn main() -> io::Result<()> {
    let mut stdout = io::stdout();

    stdout.sync_update(|stdout| {
        stdout.execute(Print("foo 1\n".to_string()))?;
        stdout.execute(Print("foo 2".to_string()))?;
        // The effects of the print command will not be present in the terminal
        // buffer, but not visible in the terminal.
        std::io::Result::Ok(())
    })?;

    // The effects of the commands will be visible.

    Ok(())

    // ==== Output ====
    // foo 1
    // foo 2
}
§Notes

This command is performed only using ANSI codes, and will do nothing on terminals that do not support ANSI codes, or this specific extension.

When rendering the screen of the terminal, the Emulator usually iterates through each visible grid cell and renders its current state. With applications updating the screen a at higher frequency this can cause tearing.

This mode attempts to mitigate that.

When the synchronization mode is enabled following render calls will keep rendering the last rendered state. The terminal Emulator keeps processing incoming text and sequences. When the synchronized update mode is disabled again the renderer may fetch the latest screen buffer state again, effectively avoiding the tearing effect by unintentionally rendering in the middle a of an application screen update.

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

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type Error = !

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

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.
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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self> ⓘ
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self> ⓘ

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more