[−][src]Struct grep_cli::CommandReader
A streaming reader for a command's output.
The purpose of this reader is to provide an easy way to execute processes whose stdout is read in a streaming way while also making the processes' stderr available when the process fails with an exit code. This makes it possible to execute processes while surfacing the underlying failure mode in the case of an error.
Moreover, by default, this reader will asynchronously read the processes' stderr. This prevents subtle deadlocking bugs for noisy processes that write a lot to stderr. Currently, the entire contents of stderr is read on to the heap.
Example
This example shows how to invoke gzip
to decompress the contents of a
file. If the gzip
command reports a failing exit status, then its stderr
is returned as an error.
use std::io::Read; use std::process::Command; use grep_cli::CommandReader; let mut cmd = Command::new("gzip"); cmd.arg("-d").arg("-c").arg("/usr/share/man/man1/ls.1.gz"); let mut rdr = CommandReader::new(&mut cmd)?; let mut contents = vec![]; rdr.read_to_end(&mut contents)?;
Methods
impl CommandReader
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pub fn new(cmd: &mut Command) -> Result<CommandReader, CommandError>
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Create a new streaming reader for the given command using the default configuration.
The caller should set everything that's required on the given command before building a reader, such as its arguments, environment and current working directory. Settings such as the stdout and stderr (but not stdin) pipes will be overridden so that they can be controlled by the reader.
If there was a problem spawning the given command, then its error is returned.
If the caller requires additional configuration for the reader
returned, then use
CommandReaderBuilder
.
Trait Implementations
impl Debug for CommandReader
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impl Read for CommandReader
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fn read(&mut self, buf: &mut [u8]) -> Result<usize>
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fn read_vectored(&mut self, bufs: &mut [IoSliceMut]) -> Result<usize, Error>
1.36.0[src]
unsafe fn initializer(&self) -> Initializer
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fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>
1.0.0[src]
fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>
1.0.0[src]
fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>
1.6.0[src]
fn by_ref(&mut self) -> &mut Self
1.0.0[src]
fn bytes(self) -> Bytes<Self>
1.0.0[src]
fn chain<R>(self, next: R) -> Chain<Self, R> where
R: Read,
1.0.0[src]
R: Read,
fn take(self, limit: u64) -> Take<Self>
1.0.0[src]
Auto Trait Implementations
impl !RefUnwindSafe for CommandReader
impl Send for CommandReader
impl Sync for CommandReader
impl Unpin for CommandReader
impl !UnwindSafe for CommandReader
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,