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|
//! Core model for netdoc parsing
use super::*;
/// A document or section that can be parsed
///
/// Normally [derived](derive_deftly_template_NetdocParseable).
pub trait NetdocParseable: Sized {
/// Document type for errors, normally its intro keyword
fn doctype_for_error() -> &'static str;
/// Is `Keyword` an intro Item Keyword for this kind of document?
///
/// This is used with 1-keyword lookahead, to allow us to push or pop
/// the parsing state into or out of a sub-document.
///
/// For signatures sections, this should report *every* recognised keyword.
fn is_intro_item_keyword(kw: KeywordRef<'_>) -> bool;
/// Parse the document from a stream of Items
///
/// Should stop before reading any keyword matching `stop_at`.
/// (Except, right at the start.)
///
/// Should also stop before reading a 2nd intro keyword,
/// so that successive calls to this function can parse
/// successive sub-documents of this kind.
///
/// Otherwise, should continue until EOF.
///
/// Must check whether the first item is this document's `is_intro_item_keyword`,
/// and error if not.
fn from_items(input: &mut ItemStream<'_>, stop_at: stop_at!()) -> Result<Self, ErrorProblem>;
}
/// A network document with (unverified) signatures
///
/// Typically implemented automatically, for `FooSigned` structs, as defined by
/// [`#[derive_deftly(NetdocSigned)]`](derive_deftly_template_NetdocSigned).
pub trait NetdocSigned {
/// The body, ie not including the signatures
type Body: Sized;
/// The signatures (the whole signature section)
type Signatures: Sized;
/// Inspect the document (and its signatures)
///
/// # Security hazard
///
/// The signature has not been verified, so the returned data must not be trusted.
fn inspect_unverified(&self) -> (&Self::Body, &Self::Signatures);
/// Obtain the actual document (and signatures), without verifying
///
/// # Security hazard
///
/// The signature has not been verified, so the returned data must not be trusted.
fn unwrap_unverified(self) -> (Self::Body, Self::Signatures);
/// Construct a new `NetdocSigned` from a body and signatures
///
/// (Called by code generated by `#[derive_deftly(NetdocSigned)]`.)
fn from_parts(body: Self::Body, signatures: Self::Signatures) -> Self;
}
/// An item (value) that can appear in a netdoc
///
/// This is the type `T` of a field `item: T` in a netdoc type.
///
/// An implementation is provided for tuples of `ItemArgumentParseable`,
/// which parses each argument in turn,
/// ignores additional arguments,
/// and rejects any Object.
///
/// Typically derived with
/// [`#[derive_deftly(ItemValueParseable)]`](derive_deftly_template_ItemValueParseable).
///
/// Signature items are special, and implement [`SignatureItemParseable`] instead.
pub trait ItemValueParseable: Sized {
/// Parse the item's value
fn from_unparsed(item: UnparsedItem<'_>) -> Result<Self, ErrorProblem>;
}
/// An (individual) argument that can appear in a netdoc
///
/// An implementations is provided for **`T: FromStr`**,
/// which expects a single argument and passes it to `FromStr`.
///
/// For netdoc arguments whose specified syntax spans multiple space-separated words,
/// use a manual implementation or a wrapper type.
pub trait ItemArgumentParseable: Sized {
/// Parse the argument
fn from_args<'s>(
args: &mut ArgumentStream<'s>,
field: &'static str,
) -> Result<Self, ErrorProblem>;
}
/// A possibly-optional Object value that can appear in netdoc
///
/// Implemented for `Option`, so that `field: Option<ObjectValue>`
/// allows parsing an optional object.
pub trait ItemObjectParseable: Sized {
/// Check that the Label is right
fn check_label(label: &str) -> Result<(), ErrorProblem>;
/// Convert the bytes of the Object (which was present) into the actual value
///
/// `input` has been base64-decoded.
fn from_bytes(input: &[u8]) -> Result<Self, ErrorProblem>;
/// Convert the bytes of the Object, if any, into the actual value
///
/// If there was an Object, `input` has been base64-decoded.
/// If there was no Object, `input` is `None`.
///
/// The provided implementation considers a missing object to be an error.
fn from_bytes_option(input: Option<&[u8]>) -> Result<Self, ErrorProblem> {
Self::from_bytes(input.ok_or(EP::MissingObject)?)
}
}
//---------- provided blanket impls ----------
impl<T: ItemObjectParseable> ItemObjectParseable for Option<T> {
fn check_label(label: &str) -> Result<(), EP> {
T::check_label(label)
}
fn from_bytes(input: &[u8]) -> Result<Self, EP> {
Ok(Some(T::from_bytes(input)?))
}
fn from_bytes_option(input: Option<&[u8]>) -> Result<Self, EP> {
let Some(input) = input else { return Ok(None) };
Self::from_bytes(input)
}
}
impl<T: FromStr> ItemArgumentParseable for T {
fn from_args<'s>(args: &mut ArgumentStream<'s>, field: &'static str) -> Result<Self, EP> {
let v = args
.next()
.ok_or(EP::MissingArgument { field })?
.parse()
.map_err(|_e| EP::InvalidArgument { field })?;
Ok(v)
}
}
/// implement [`ItemValueParseable`] for a particular tuple size
macro_rules! item_value_parseable_for_tuple {
{ $($i:literal)* } => { paste! {
impl< $( [<T$i>]: ItemArgumentParseable, )* >
ItemValueParseable for ( $( [<T$i>], )* )
{
fn from_unparsed(
#[allow(unused_mut)]
mut item: UnparsedItem<'_>,
) -> Result<Self, ErrorProblem> {
let r = ( $(
<[<T$i>] as ItemArgumentParseable>::from_args(
item.args_mut(),
stringify!($i),
)?,
)* );
if item.object().is_some() { return Err(EP::ObjectUnexpected) }
Ok(r)
}
}
} }
}
item_value_parseable_for_tuple! {}
item_value_parseable_for_tuple! { 0 }
item_value_parseable_for_tuple! { 0 1 }
item_value_parseable_for_tuple! { 0 1 2 }
item_value_parseable_for_tuple! { 0 1 2 3 }
item_value_parseable_for_tuple! { 0 1 2 3 4 }
item_value_parseable_for_tuple! { 0 1 2 3 4 5 }
item_value_parseable_for_tuple! { 0 1 2 3 4 5 6 }
item_value_parseable_for_tuple! { 0 1 2 3 4 5 6 7 }
item_value_parseable_for_tuple! { 0 1 2 3 4 5 6 7 8 }
item_value_parseable_for_tuple! { 0 1 2 3 4 5 6 7 8 9 }
|
