Merging upstream version 1.74.1+dfsg1.

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

1 files changed, 145 insertions, 0 deletions

diff --git a/vendor/gix-packetline-blocking/src/decode.rs b/vendor/gix-packetline-blocking/src/decode.rs
new file mode 100644
index 000000000..35d2b5149
--- /dev/null
+++ b/vendor/gix-packetline-blocking/src/decode.rs
@@ -0,0 +1,145 @@
+use bstr::BString;
+
+use crate::{PacketLineRef, DELIMITER_LINE, FLUSH_LINE, MAX_DATA_LEN, MAX_LINE_LEN, RESPONSE_END_LINE, U16_HEX_BYTES};
+
+/// The error used in the [`decode`][mod@crate::decode] module
+#[derive(Debug, thiserror::Error)]
+#[allow(missing_docs)]
+pub enum Error {
+    #[error("Failed to decode the first four hex bytes indicating the line length: {err}")]
+    HexDecode { err: String },
+    #[error("The data received claims to be larger than than the maximum allowed size: got {length_in_bytes}, exceeds {MAX_DATA_LEN}")]
+    DataLengthLimitExceeded { length_in_bytes: usize },
+    #[error("Received an invalid empty line")]
+    DataIsEmpty,
+    #[error("Received an invalid line of length 3")]
+    InvalidLineLength,
+    #[error("{data:?} - consumed {bytes_consumed} bytes")]
+    Line { data: BString, bytes_consumed: usize },
+    #[error("Needing {bytes_needed} additional bytes to decode the line successfully")]
+    NotEnoughData { bytes_needed: usize },
+}
+
+///
+pub mod band {
+    /// The error used in [`PacketLineRef::decode_band()`][super::PacketLineRef::decode_band()].
+    #[derive(Debug, thiserror::Error)]
+    #[allow(missing_docs)]
+    pub enum Error {
+        #[error("attempt to decode a non-side channel line or input was malformed: {band_id}")]
+        InvalidSideBand { band_id: u8 },
+        #[error("attempt to decode a non-data line into a side-channel band")]
+        NonDataLine,
+    }
+}
+
+/// A utility return type to support incremental parsing of packet lines.
+#[derive(Debug, Clone)]
+pub enum Stream<'a> {
+    /// Indicate a single packet line was parsed completely
+    Complete {
+        /// The parsed packet line
+        line: PacketLineRef<'a>,
+        /// The amount of bytes consumed from input
+        bytes_consumed: usize,
+    },
+    /// A packet line could not yet be parsed due to missing bytes
+    Incomplete {
+        /// The amount of additional bytes needed for the parsing to complete
+        bytes_needed: usize,
+    },
+}
+
+/// The result of [`hex_prefix()`] indicating either a special packet line or the amount of wanted bytes
+pub enum PacketLineOrWantedSize<'a> {
+    /// The special kind of packet line decoded from the hex prefix. It never contains actual data.
+    Line(PacketLineRef<'a>),
+    /// The amount of bytes indicated by the hex prefix of the packet line.
+    Wanted(u16),
+}
+
+/// Decode the `four_bytes` packet line prefix provided in hexadecimal form and check it for validity.
+pub fn hex_prefix(four_bytes: &[u8]) -> Result<PacketLineOrWantedSize<'_>, Error> {
+    debug_assert_eq!(four_bytes.len(), 4, "need four hex bytes");
+    for (line_bytes, line_type) in &[
+        (FLUSH_LINE, PacketLineRef::Flush),
+        (DELIMITER_LINE, PacketLineRef::Delimiter),
+        (RESPONSE_END_LINE, PacketLineRef::ResponseEnd),
+    ] {
+        if four_bytes == *line_bytes {
+            return Ok(PacketLineOrWantedSize::Line(*line_type));
+        }
+    }
+
+    let mut buf = [0u8; U16_HEX_BYTES / 2];
+    faster_hex::hex_decode(four_bytes, &mut buf).map_err(|err| Error::HexDecode { err: err.to_string() })?;
+    let wanted_bytes = u16::from_be_bytes(buf);
+
+    if wanted_bytes == 3 {
+        return Err(Error::InvalidLineLength);
+    }
+    if wanted_bytes == 4 {
+        return Err(Error::DataIsEmpty);
+    }
+    debug_assert!(
+        wanted_bytes as usize > U16_HEX_BYTES,
+        "by now there should be more wanted bytes than prefix bytes"
+    );
+    Ok(PacketLineOrWantedSize::Wanted(wanted_bytes - U16_HEX_BYTES as u16))
+}
+
+/// Obtain a `PacketLine` from `data` after assuring `data` is small enough to fit.
+pub fn to_data_line(data: &[u8]) -> Result<PacketLineRef<'_>, Error> {
+    if data.len() > MAX_LINE_LEN {
+        return Err(Error::DataLengthLimitExceeded {
+            length_in_bytes: data.len(),
+        });
+    }
+
+    Ok(PacketLineRef::Data(data))
+}
+
+/// Decode `data` as packet line while reporting whether the data is complete or not using a [`Stream`].
+pub fn streaming(data: &[u8]) -> Result<Stream<'_>, Error> {
+    let data_len = data.len();
+    if data_len < U16_HEX_BYTES {
+        return Ok(Stream::Incomplete {
+            bytes_needed: U16_HEX_BYTES - data_len,
+        });
+    }
+    let wanted_bytes = match hex_prefix(&data[..U16_HEX_BYTES])? {
+        PacketLineOrWantedSize::Wanted(s) => s as usize,
+        PacketLineOrWantedSize::Line(line) => {
+            return Ok(Stream::Complete {
+                line,
+                bytes_consumed: 4,
+            })
+        }
+    } + U16_HEX_BYTES;
+    if wanted_bytes > MAX_LINE_LEN {
+        return Err(Error::DataLengthLimitExceeded {
+            length_in_bytes: wanted_bytes,
+        });
+    }
+    if data_len < wanted_bytes {
+        return Ok(Stream::Incomplete {
+            bytes_needed: wanted_bytes - data_len,
+        });
+    }
+
+    Ok(Stream::Complete {
+        line: to_data_line(&data[U16_HEX_BYTES..wanted_bytes])?,
+        bytes_consumed: wanted_bytes,
+    })
+}
+
+/// Decode an entire packet line from data or fail.
+///
+/// Note that failure also happens if there is not enough data to parse a complete packet line, as opposed to [`streaming()`] decoding
+/// succeeds in that case, stating how much more bytes are required.
+pub fn all_at_once(data: &[u8]) -> Result<PacketLineRef<'_>, Error> {
+    match streaming(data)? {
+        Stream::Complete { line, .. } => Ok(line),
+        Stream::Incomplete { bytes_needed } => Err(Error::NotEnoughData { bytes_needed }),
+    }
+}