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use crate::body::calculate_max_input;
use crate::util::Writer;
use crate::Error;
use super::state::{RecvResponse, SendBody};
use super::Call;
impl Call<SendBody> {
/// Write request body from `input` to `output`.
///
/// This is called repeatedly until the entire body has been sent. The output buffer is filled
/// as much as possible for each call.
///
/// Depending on request headers, the output might be `transfer-encoding: chunked`. Chunking means
/// the output is slightly larger than the input due to the extra length headers per chunk.
/// When not doing chunked, the input/output will be the same per call.
///
/// The result `(usize, usize)` is `(input consumed, output used)`.
///
/// **Important**
///
/// To indicate that the body is fully sent, you call write with an `input` parameter set to `&[]`.
/// This ends the `transfer-encoding: chunked` and ensures the state is correct to proceed.
pub fn write(&mut self, input: &[u8], output: &mut [u8]) -> Result<(usize, usize), Error> {
let mut w = Writer::new(output);
if !input.is_empty() && self.inner.state.writer.is_ended() {
return Err(Error::BodyContentAfterFinish);
}
if let Some(left) = self.inner.state.writer.left_to_send() {
if input.len() as u64 > left {
return Err(Error::BodyLargerThanContentLength);
}
}
let input_used = self.inner.state.writer.write(input, &mut w);
let output_used = w.len();
Ok((input_used, output_used))
}
/// Helper to avoid copying memory.
///
/// When the transfer is _NOT_ chunked, `write()` just copies the `input` to the `output`.
/// This memcopy might be possible to avoid if the user can use the `input` buffer directly
/// against the transport.
///
/// This function is used to "report" how much of the input that has been used. It's effectively
/// the same as the first `usize` in the pair returned by `write()`.
pub fn consume_direct_write(&mut self, amount: usize) -> Result<(), Error> {
if let Some(left) = self.inner.state.writer.left_to_send() {
if amount as u64 > left {
return Err(Error::BodyLargerThanContentLength);
}
} else {
return Err(Error::BodyIsChunked);
}
self.inner.state.writer.consume_direct_write(amount);
Ok(())
}
/// Calculate the max amount of input we can transfer to fill the `output_len`.
///
/// For chunked transfer, the input is less than the output.
pub fn calculate_max_input(&self, output_len: usize) -> usize {
// For non-chunked, the entire output can be used.
if !self.is_chunked() {
return output_len;
}
calculate_max_input(output_len)
}
/// Test if call is chunked.
///
/// This might need some processing, hence the &mut and
pub fn is_chunked(&self) -> bool {
self.inner.state.writer.is_chunked()
}
/// Check whether the request body is fully sent.
///
/// For requests with a `content-length` header set, this will only become `true` once the
/// number of bytes communicated have been sent. For chunked transfer, this becomes `true`
/// after calling `write()` with an input of `&[]`.
pub fn can_proceed(&self) -> bool {
self.inner.state.writer.is_ended()
}
/// Proceed to the next state.
///
/// Returns `None` if it's not possible to proceed. It's guaranteed that if `can_proceed()` returns
/// `true`, this will result in `Some`.
pub fn proceed(self) -> Option<Call<RecvResponse>> {
if !self.can_proceed() {
return None;
}
Some(Call::wrap(self.inner))
}
}