Merging upstream version 1.70.0+dfsg2.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 407 insertions, 0 deletions

diff --git a/vendor/base64/src/write/encoder.rs b/vendor/base64/src/write/encoder.rs
new file mode 100644
index 000000000..1c19bb42a
--- /dev/null
+++ b/vendor/base64/src/write/encoder.rs
@@ -0,0 +1,407 @@
+use crate::engine::Engine;
+use std::{
+    cmp, fmt, io,
+    io::{ErrorKind, Result},
+};
+
+pub(crate) const BUF_SIZE: usize = 1024;
+/// The most bytes whose encoding will fit in `BUF_SIZE`
+const MAX_INPUT_LEN: usize = BUF_SIZE / 4 * 3;
+// 3 bytes of input = 4 bytes of base64, always (because we don't allow line wrapping)
+const MIN_ENCODE_CHUNK_SIZE: usize = 3;
+
+/// A `Write` implementation that base64 encodes data before delegating to the wrapped writer.
+///
+/// Because base64 has special handling for the end of the input data (padding, etc), there's a
+/// `finish()` method on this type that encodes any leftover input bytes and adds padding if
+/// appropriate. It's called automatically when deallocated (see the `Drop` implementation), but
+/// any error that occurs when invoking the underlying writer will be suppressed. If you want to
+/// handle such errors, call `finish()` yourself.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::Write;
+/// use base64::engine::general_purpose;
+///
+/// // use a vec as the simplest possible `Write` -- in real code this is probably a file, etc.
+/// let mut enc = base64::write::EncoderWriter::new(Vec::new(), &general_purpose::STANDARD);
+///
+/// // handle errors as you normally would
+/// enc.write_all(b"asdf").unwrap();
+///
+/// // could leave this out to be called by Drop, if you don't care
+/// // about handling errors or getting the delegate writer back
+/// let delegate = enc.finish().unwrap();
+///
+/// // base64 was written to the writer
+/// assert_eq!(b"YXNkZg==", &delegate[..]);
+///
+/// ```
+///
+/// # Panics
+///
+/// Calling `write()` (or related methods) or `finish()` after `finish()` has completed without
+/// error is invalid and will panic.
+///
+/// # Errors
+///
+/// Base64 encoding itself does not generate errors, but errors from the wrapped writer will be
+/// returned as per the contract of `Write`.
+///
+/// # Performance
+///
+/// It has some minor performance loss compared to encoding slices (a couple percent).
+/// It does not do any heap allocation.
+///
+/// # Limitations
+///
+/// Owing to the specification of the `write` and `flush` methods on the `Write` trait and their
+/// implications for a buffering implementation, these methods may not behave as expected. In
+/// particular, calling `write_all` on this interface may fail with `io::ErrorKind::WriteZero`.
+/// See the documentation of the `Write` trait implementation for further details.
+pub struct EncoderWriter<'e, E: Engine, W: io::Write> {
+    engine: &'e E,
+    /// Where encoded data is written to. It's an Option as it's None immediately before Drop is
+    /// called so that finish() can return the underlying writer. None implies that finish() has
+    /// been called successfully.
+    delegate: Option<W>,
+    /// Holds a partial chunk, if any, after the last `write()`, so that we may then fill the chunk
+    /// with the next `write()`, encode it, then proceed with the rest of the input normally.
+    extra_input: [u8; MIN_ENCODE_CHUNK_SIZE],
+    /// How much of `extra` is occupied, in `[0, MIN_ENCODE_CHUNK_SIZE]`.
+    extra_input_occupied_len: usize,
+    /// Buffer to encode into. May hold leftover encoded bytes from a previous write call that the underlying writer
+    /// did not write last time.
+    output: [u8; BUF_SIZE],
+    /// How much of `output` is occupied with encoded data that couldn't be written last time
+    output_occupied_len: usize,
+    /// panic safety: don't write again in destructor if writer panicked while we were writing to it
+    panicked: bool,
+}
+
+impl<'e, E: Engine, W: io::Write> fmt::Debug for EncoderWriter<'e, E, W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "extra_input: {:?} extra_input_occupied_len:{:?} output[..5]: {:?} output_occupied_len: {:?}",
+            self.extra_input,
+            self.extra_input_occupied_len,
+            &self.output[0..5],
+            self.output_occupied_len
+        )
+    }
+}
+
+impl<'e, E: Engine, W: io::Write> EncoderWriter<'e, E, W> {
+    /// Create a new encoder that will write to the provided delegate writer.
+    pub fn new(delegate: W, engine: &'e E) -> EncoderWriter<'e, E, W> {
+        EncoderWriter {
+            engine,
+            delegate: Some(delegate),
+            extra_input: [0u8; MIN_ENCODE_CHUNK_SIZE],
+            extra_input_occupied_len: 0,
+            output: [0u8; BUF_SIZE],
+            output_occupied_len: 0,
+            panicked: false,
+        }
+    }
+
+    /// Encode all remaining buffered data and write it, including any trailing incomplete input
+    /// triples and associated padding.
+    ///
+    /// Once this succeeds, no further writes or calls to this method are allowed.
+    ///
+    /// This may write to the delegate writer multiple times if the delegate writer does not accept
+    /// all input provided to its `write` each invocation.
+    ///
+    /// If you don't care about error handling, it is not necessary to call this function, as the
+    /// equivalent finalization is done by the Drop impl.
+    ///
+    /// Returns the writer that this was constructed around.
+    ///
+    /// # Errors
+    ///
+    /// The first error that is not of `ErrorKind::Interrupted` will be returned.
+    pub fn finish(&mut self) -> Result<W> {
+        // If we could consume self in finish(), we wouldn't have to worry about this case, but
+        // finish() is retryable in the face of I/O errors, so we can't consume here.
+        if self.delegate.is_none() {
+            panic!("Encoder has already had finish() called");
+        };
+
+        self.write_final_leftovers()?;
+
+        let writer = self.delegate.take().expect("Writer must be present");
+
+        Ok(writer)
+    }
+
+    /// Write any remaining buffered data to the delegate writer.
+    fn write_final_leftovers(&mut self) -> Result<()> {
+        if self.delegate.is_none() {
+            // finish() has already successfully called this, and we are now in drop() with a None
+            // writer, so just no-op
+            return Ok(());
+        }
+
+        self.write_all_encoded_output()?;
+
+        if self.extra_input_occupied_len > 0 {
+            let encoded_len = self
+                .engine
+                .encode_slice(
+                    &self.extra_input[..self.extra_input_occupied_len],
+                    &mut self.output[..],
+                )
+                .expect("buffer is large enough");
+
+            self.output_occupied_len = encoded_len;
+
+            self.write_all_encoded_output()?;
+
+            // write succeeded, do not write the encoding of extra again if finish() is retried
+            self.extra_input_occupied_len = 0;
+        }
+
+        Ok(())
+    }
+
+    /// Write as much of the encoded output to the delegate writer as it will accept, and store the
+    /// leftovers to be attempted at the next write() call. Updates `self.output_occupied_len`.
+    ///
+    /// # Errors
+    ///
+    /// Errors from the delegate writer are returned. In the case of an error,
+    /// `self.output_occupied_len` will not be updated, as errors from `write` are specified to mean
+    /// that no write took place.
+    fn write_to_delegate(&mut self, current_output_len: usize) -> Result<()> {
+        self.panicked = true;
+        let res = self
+            .delegate
+            .as_mut()
+            .expect("Writer must be present")
+            .write(&self.output[..current_output_len]);
+        self.panicked = false;
+
+        res.map(|consumed| {
+            debug_assert!(consumed <= current_output_len);
+
+            if consumed < current_output_len {
+                self.output_occupied_len = current_output_len.checked_sub(consumed).unwrap();
+                // If we're blocking on I/O, the minor inefficiency of copying bytes to the
+                // start of the buffer is the least of our concerns...
+                // TODO Rotate moves more than we need to; copy_within now stable.
+                self.output.rotate_left(consumed);
+            } else {
+                self.output_occupied_len = 0;
+            }
+        })
+    }
+
+    /// Write all buffered encoded output. If this returns `Ok`, `self.output_occupied_len` is `0`.
+    ///
+    /// This is basically write_all for the remaining buffered data but without the undesirable
+    /// abort-on-`Ok(0)` behavior.
+    ///
+    /// # Errors
+    ///
+    /// Any error emitted by the delegate writer abort the write loop and is returned, unless it's
+    /// `Interrupted`, in which case the error is ignored and writes will continue.
+    fn write_all_encoded_output(&mut self) -> Result<()> {
+        while self.output_occupied_len > 0 {
+            let remaining_len = self.output_occupied_len;
+            match self.write_to_delegate(remaining_len) {
+                // try again on interrupts ala write_all
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                // other errors return
+                Err(e) => return Err(e),
+                // success no-ops because remaining length is already updated
+                Ok(_) => {}
+            };
+        }
+
+        debug_assert_eq!(0, self.output_occupied_len);
+        Ok(())
+    }
+
+    /// Unwraps this `EncoderWriter`, returning the base writer it writes base64 encoded output
+    /// to.
+    ///
+    /// Normally this method should not be needed, since `finish()` returns the inner writer if
+    /// it completes successfully. That will also ensure all data has been flushed, which the
+    /// `into_inner()` function does *not* do.
+    ///
+    /// Calling this method after `finish()` has completed successfully will panic, since the
+    /// writer has already been returned.
+    ///
+    /// This method may be useful if the writer implements additional APIs beyond the `Write`
+    /// trait. Note that the inner writer might be in an error state or have an incomplete
+    /// base64 string written to it.
+    pub fn into_inner(mut self) -> W {
+        self.delegate
+            .take()
+            .expect("Encoder has already had finish() called")
+    }
+}
+
+impl<'e, E: Engine, W: io::Write> io::Write for EncoderWriter<'e, E, W> {
+    /// Encode input and then write to the delegate writer.
+    ///
+    /// Under non-error circumstances, this returns `Ok` with the value being the number of bytes
+    /// of `input` consumed. The value may be `0`, which interacts poorly with `write_all`, which
+    /// interprets `Ok(0)` as an error, despite it being allowed by the contract of `write`. See
+    /// <https://github.com/rust-lang/rust/issues/56889> for more on that.
+    ///
+    /// If the previous call to `write` provided more (encoded) data than the delegate writer could
+    /// accept in a single call to its `write`, the remaining data is buffered. As long as buffered
+    /// data is present, subsequent calls to `write` will try to write the remaining buffered data
+    /// to the delegate and return either `Ok(0)` -- and therefore not consume any of `input` -- or
+    /// an error.
+    ///
+    /// # Errors
+    ///
+    /// Any errors emitted by the delegate writer are returned.
+    fn write(&mut self, input: &[u8]) -> Result<usize> {
+        if self.delegate.is_none() {
+            panic!("Cannot write more after calling finish()");
+        }
+
+        if input.is_empty() {
+            return Ok(0);
+        }
+
+        // The contract of `Write::write` places some constraints on this implementation:
+        // - a call to `write()` represents at most one call to a wrapped `Write`, so we can't
+        // iterate over the input and encode multiple chunks.
+        // - Errors mean that "no bytes were written to this writer", so we need to reset the
+        // internal state to what it was before the error occurred
+
+        // before reading any input, write any leftover encoded output from last time
+        if self.output_occupied_len > 0 {
+            let current_len = self.output_occupied_len;
+            return self
+                .write_to_delegate(current_len)
+                // did not read any input
+                .map(|_| 0);
+        }
+
+        debug_assert_eq!(0, self.output_occupied_len);
+
+        // how many bytes, if any, were read into `extra` to create a triple to encode
+        let mut extra_input_read_len = 0;
+        let mut input = input;
+
+        let orig_extra_len = self.extra_input_occupied_len;
+
+        let mut encoded_size = 0;
+        // always a multiple of MIN_ENCODE_CHUNK_SIZE
+        let mut max_input_len = MAX_INPUT_LEN;
+
+        // process leftover un-encoded input from last write
+        if self.extra_input_occupied_len > 0 {
+            debug_assert!(self.extra_input_occupied_len < 3);
+            if input.len() + self.extra_input_occupied_len >= MIN_ENCODE_CHUNK_SIZE {
+                // Fill up `extra`, encode that into `output`, and consume as much of the rest of
+                // `input` as possible.
+                // We could write just the encoding of `extra` by itself but then we'd have to
+                // return after writing only 4 bytes, which is inefficient if the underlying writer
+                // would make a syscall.
+                extra_input_read_len = MIN_ENCODE_CHUNK_SIZE - self.extra_input_occupied_len;
+                debug_assert!(extra_input_read_len > 0);
+                // overwrite only bytes that weren't already used. If we need to rollback extra_len
+                // (when the subsequent write errors), the old leading bytes will still be there.
+                self.extra_input[self.extra_input_occupied_len..MIN_ENCODE_CHUNK_SIZE]
+                    .copy_from_slice(&input[0..extra_input_read_len]);
+
+                let len = self.engine.internal_encode(
+                    &self.extra_input[0..MIN_ENCODE_CHUNK_SIZE],
+                    &mut self.output[..],
+                );
+                debug_assert_eq!(4, len);
+
+                input = &input[extra_input_read_len..];
+
+                // consider extra to be used up, since we encoded it
+                self.extra_input_occupied_len = 0;
+                // don't clobber where we just encoded to
+                encoded_size = 4;
+                // and don't read more than can be encoded
+                max_input_len = MAX_INPUT_LEN - MIN_ENCODE_CHUNK_SIZE;
+
+            // fall through to normal encoding
+            } else {
+                // `extra` and `input` are non empty, but `|extra| + |input| < 3`, so there must be
+                // 1 byte in each.
+                debug_assert_eq!(1, input.len());
+                debug_assert_eq!(1, self.extra_input_occupied_len);
+
+                self.extra_input[self.extra_input_occupied_len] = input[0];
+                self.extra_input_occupied_len += 1;
+                return Ok(1);
+            };
+        } else if input.len() < MIN_ENCODE_CHUNK_SIZE {
+            // `extra` is empty, and `input` fits inside it
+            self.extra_input[0..input.len()].copy_from_slice(input);
+            self.extra_input_occupied_len = input.len();
+            return Ok(input.len());
+        };
+
+        // either 0 or 1 complete chunks encoded from extra
+        debug_assert!(encoded_size == 0 || encoded_size == 4);
+        debug_assert!(
+            // didn't encode extra input
+            MAX_INPUT_LEN == max_input_len
+                // encoded one triple
+                || MAX_INPUT_LEN == max_input_len + MIN_ENCODE_CHUNK_SIZE
+        );
+
+        // encode complete triples only
+        let input_complete_chunks_len = input.len() - (input.len() % MIN_ENCODE_CHUNK_SIZE);
+        let input_chunks_to_encode_len = cmp::min(input_complete_chunks_len, max_input_len);
+        debug_assert_eq!(0, max_input_len % MIN_ENCODE_CHUNK_SIZE);
+        debug_assert_eq!(0, input_chunks_to_encode_len % MIN_ENCODE_CHUNK_SIZE);
+
+        encoded_size += self.engine.internal_encode(
+            &input[..(input_chunks_to_encode_len)],
+            &mut self.output[encoded_size..],
+        );
+
+        // not updating `self.output_occupied_len` here because if the below write fails, it should
+        // "never take place" -- the buffer contents we encoded are ignored and perhaps retried
+        // later, if the consumer chooses.
+
+        self.write_to_delegate(encoded_size)
+            // no matter whether we wrote the full encoded buffer or not, we consumed the same
+            // input
+            .map(|_| extra_input_read_len + input_chunks_to_encode_len)
+            .map_err(|e| {
+                // in case we filled and encoded `extra`, reset extra_len
+                self.extra_input_occupied_len = orig_extra_len;
+
+                e
+            })
+    }
+
+    /// Because this is usually treated as OK to call multiple times, it will *not* flush any
+    /// incomplete chunks of input or write padding.
+    /// # Errors
+    ///
+    /// The first error that is not of [`ErrorKind::Interrupted`] will be returned.
+    fn flush(&mut self) -> Result<()> {
+        self.write_all_encoded_output()?;
+        self.delegate
+            .as_mut()
+            .expect("Writer must be present")
+            .flush()
+    }
+}
+
+impl<'e, E: Engine, W: io::Write> Drop for EncoderWriter<'e, E, W> {
+    fn drop(&mut self) {
+        if !self.panicked {
+            // like `BufWriter`, ignore errors during drop
+            let _ = self.write_final_leftovers();
+        }
+    }
+}