Struct JsonWriter

pub struct JsonWriter<T> { /* private fields */ }

Type-safe machine output implementation of crate::ToolIO

Implementations

impl<T> JsonWriter<T>

pub fn new_buffers<'a, O, E>( format: Option<Format>, stdout: O, stderr: E, ) -> Self

where O: Write + 'static, E: Write + 'static,

Create a new writer that doesn’t support machine output at all, with the given streams underlying it.

pub fn new(format: Option<Format>) -> Self

Create a new Writer with the specified format.

Passing None for format implies no output via the machine function.

pub fn new_test(format: Option<Format>, test_buffers: &TestBuffers) -> Self

Returns a writer backed by string buffers that can be extracted after the writer is done with

pub fn simple_writer(self) -> Writer

Allow using this writer as a SimpleWriter. This is useful for calling other tools that do not use JsonWriter.

pub fn stderr(&mut self) -> &mut Box<dyn Write>

impl<T> JsonWriter<T>

where T: Serialize,

pub fn machine_many<I: IntoIterator<Item = T>>( &mut self, output: I, ) -> Result<()>

Write the items from the iterable object to standard output.

This is a no-op if is_machine returns false.

pub fn machine(&mut self, output: &T) -> Result<()>

Write the item to standard output.

This is a no-op if is_machine returns false.

pub fn machine_or<D: Display>(&mut self, value: &T, or: D) -> Result<()>

If this object is outputting machine output, print the item’s machine representation to stdout. Otherwise, print the display item given.

pub fn machine_or_write<D: Display>(&mut self, value: &T, or: D) -> Result<()>

If this object is outputting machine output, print the item’s machine representation to stdout. Otherwise, write! the display item given.

pub fn machine_or_else<F, R>(&mut self, value: &T, f: F) -> Result<()>

where F: FnOnce() -> R, R: Display,

If this object is outputting machine output, prints the item’s machine representation to stdout. Otherwise, call the closure with the object and print the result.

pub fn format(&self) -> Option<Format>

pub fn formatted<J: Serialize>(&mut self, output: &J) -> Result<()>

Trait Implementations

impl<T> ToolIO for JsonWriter<T>

where T: Serialize,

type OutputItem = T

The type of object that is expected for the Self::item call (or any machine output writing functions that may be added by an implementation)

fn is_machine_supported() -> bool

Whether this can theoretically support machine output given the right configuration.

fn is_machine(&self) -> bool

Returns true if the receiver was configured to output for machines.

fn stderr(&mut self) -> &mut Box<dyn Write>

Returns an error stream that errors can be written to.

fn item(&mut self, value: &T) -> Result<()>

where T: Display,

Displays the item in whatever formatted style is most appropriate based on is_machine and the underlying implementation

fn has_schema() -> bool

Is a schema of the output type available.

fn try_print_schema(&mut self) -> Result<()>

fn print(&mut self, value: impl Display) -> Result<()>

Writes the value to standard output without a newline.

fn line(&mut self, value: impl Display) -> Result<()>

Writes the value to standard output with a newline.

impl<T> Write for JsonWriter<T>

where T: Serialize,

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

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

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

Like write, except that it writes from a slice of buffers.

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.

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

Attempts to write an entire buffer into this writer.

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.

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

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

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