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//! Protobuf encoding and decoding errors.
use alloc::borrow::Cow;
use alloc::boxed::Box;
use alloc::vec::Vec;
use core::fmt;
/// A Protobuf message decoding error.
///
/// `DecodeError` indicates that the input buffer does not contain a valid
/// Protobuf message. The error details should be considered 'best effort': in
/// general it is not possible to exactly pinpoint why data is malformed.
#[derive(Clone, PartialEq, Eq)]
pub struct DecodeError {
inner: Box<Inner>,
}
#[derive(Clone, PartialEq, Eq)]
struct Inner {
/// A 'best effort' root cause description.
description: Cow<'static, str>,
/// A stack of (message, field) name pairs, which identify the specific
/// message type and field where decoding failed. The stack contains an
/// entry per level of nesting.
stack: Vec<(&'static str, &'static str)>,
}
impl DecodeError {
/// Creates a new `DecodeError` with a 'best effort' root cause description.
///
/// Meant to be used only by `Message` implementations.
#[doc(hidden)]
#[cold]
pub fn new(description: impl Into<Cow<'static, str>>) -> DecodeError {
DecodeError {
inner: Box::new(Inner {
description: description.into(),
stack: Vec::new(),
}),
}
}
/// Pushes a (message, field) name location pair on to the location stack.
///
/// Meant to be used only by `Message` implementations.
#[doc(hidden)]
pub fn push(&mut self, message: &'static str, field: &'static str) {
self.inner.stack.push((message, field));
}
}
impl fmt::Debug for DecodeError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("DecodeError")
.field("description", &self.inner.description)
.field("stack", &self.inner.stack)
.finish()
}
}
impl fmt::Display for DecodeError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("failed to decode Protobuf message: ")?;
for &(message, field) in &self.inner.stack {
write!(f, "{}.{}: ", message, field)?;
}
f.write_str(&self.inner.description)
}
}
#[cfg(feature = "std")]
impl std::error::Error for DecodeError {}
#[cfg(feature = "std")]
impl From<DecodeError> for std::io::Error {
fn from(error: DecodeError) -> std::io::Error {
std::io::Error::new(std::io::ErrorKind::InvalidData, error)
}
}
/// A Protobuf message encoding error.
///
/// `EncodeError` always indicates that a message failed to encode because the
/// provided buffer had insufficient capacity. Message encoding is otherwise
/// infallible.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub struct EncodeError {
required: usize,
remaining: usize,
}
impl EncodeError {
/// Creates a new `EncodeError`.
pub(crate) fn new(required: usize, remaining: usize) -> EncodeError {
EncodeError {
required,
remaining,
}
}
/// Returns the required buffer capacity to encode the message.
pub fn required_capacity(&self) -> usize {
self.required
}
/// Returns the remaining length in the provided buffer at the time of encoding.
pub fn remaining(&self) -> usize {
self.remaining
}
}
impl fmt::Display for EncodeError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"failed to encode Protobuf message; insufficient buffer capacity (required: {}, remaining: {})",
self.required, self.remaining
)
}
}
#[cfg(feature = "std")]
impl std::error::Error for EncodeError {}
#[cfg(feature = "std")]
impl From<EncodeError> for std::io::Error {
fn from(error: EncodeError) -> std::io::Error {
std::io::Error::new(std::io::ErrorKind::InvalidInput, error)
}
}