mod group;
mod map;
mod message;
mod oneof;
mod scalar;
use std::fmt;
use std::slice;
use anyhow::{bail, Error};
use proc_macro2::TokenStream;
use quote::quote;
use syn::punctuated::Punctuated;
use syn::{Attribute, Expr, ExprLit, Lit, LitBool, LitInt, Meta, MetaNameValue, Token};
#[derive(Clone)]
pub enum Field {
/// A scalar field.
Scalar(scalar::Field),
/// A message field.
Message(message::Field),
/// A map field.
Map(map::Field),
/// A oneof field.
Oneof(oneof::Field),
/// A group field.
Group(group::Field),
}
impl Field {
/// Creates a new `Field` from an iterator of field attributes.
///
/// If the meta items are invalid, an error will be returned.
/// If the field should be ignored, `None` is returned.
pub fn new(attrs: Vec<Attribute>, inferred_tag: Option<u32>) -> Result<Option<Field>, Error> {
let attrs = prost_attrs(attrs)?;
// TODO: check for ignore attribute.
let field = if let Some(field) = scalar::Field::new(&attrs, inferred_tag)? {
Field::Scalar(field)
} else if let Some(field) = message::Field::new(&attrs, inferred_tag)? {
Field::Message(field)
} else if let Some(field) = map::Field::new(&attrs, inferred_tag)? {
Field::Map(field)
} else if let Some(field) = oneof::Field::new(&attrs)? {
Field::Oneof(field)
} else if let Some(field) = group::Field::new(&attrs, inferred_tag)? {
Field::Group(field)
} else {
bail!("no type attribute");
};
Ok(Some(field))
}
/// Creates a new oneof `Field` from an iterator of field attributes.
///
/// If the meta items are invalid, an error will be returned.
/// If the field should be ignored, `None` is returned.
pub fn new_oneof(attrs: Vec<Attribute>) -> Result<Option<Field>, Error> {
let attrs = prost_attrs(attrs)?;
// TODO: check for ignore attribute.
let field = if let Some(field) = scalar::Field::new_oneof(&attrs)? {
Field::Scalar(field)
} else if let Some(field) = message::Field::new_oneof(&attrs)? {
Field::Message(field)
} else if let Some(field) = map::Field::new_oneof(&attrs)? {
Field::Map(field)
} else if let Some(field) = group::Field::new_oneof(&attrs)? {
Field::Group(field)
} else {
bail!("no type attribute for oneof field");
};
Ok(Some(field))
}
pub fn tags(&self) -> Vec<u32> {
match *self {
Field::Scalar(ref scalar) => vec![scalar.tag],
Field::Message(ref message) => vec![message.tag],
Field::Map(ref map) => vec![map.tag],
Field::Oneof(ref oneof) => oneof.tags.clone(),
Field::Group(ref group) => vec![group.tag],
}
}
/// Returns a statement which encodes the field.
pub fn encode(&self, ident: TokenStream) -> TokenStream {
match *self {
Field::Scalar(ref scalar) => scalar.encode(ident),
Field::Message(ref message) => message.encode(ident),
Field::Map(ref map) => map.encode(ident),
Field::Oneof(ref oneof) => oneof.encode(ident),
Field::Group(ref group) => group.encode(ident),
}
}
/// Returns an expression which evaluates to the result of merging a decoded
/// value into the field.
pub fn merge(&self, ident: TokenStream) -> TokenStream {
match *self {
Field::Scalar(ref scalar) => scalar.merge(ident),
Field::Message(ref message) => message.merge(ident),
Field::Map(ref map) => map.merge(ident),
Field::Oneof(ref oneof) => oneof.merge(ident),
Field::Group(ref group) => group.merge(ident),
}
}
/// Returns an expression which evaluates to the encoded length of the field.
pub fn encoded_len(&self, ident: TokenStream) -> TokenStream {
match *self {
Field::Scalar(ref scalar) => scalar.encoded_len(ident),
Field::Map(ref map) => map.encoded_len(ident),
Field::Message(ref msg) => msg.encoded_len(ident),
Field::Oneof(ref oneof) => oneof.encoded_len(ident),
Field::Group(ref group) => group.encoded_len(ident),
}
}
/// Returns a statement which clears the field.
pub fn clear(&self, ident: TokenStream) -> TokenStream {
match *self {
Field::Scalar(ref scalar) => scalar.clear(ident),
Field::Message(ref message) => message.clear(ident),
Field::Map(ref map) => map.clear(ident),
Field::Oneof(ref oneof) => oneof.clear(ident),
Field::Group(ref group) => group.clear(ident),
}
}
pub fn default(&self) -> TokenStream {
match *self {
Field::Scalar(ref scalar) => scalar.default(),
_ => quote!(::core::default::Default::default()),
}
}
/// Produces the fragment implementing debug for the given field.
pub fn debug(&self, ident: TokenStream) -> TokenStream {
match *self {
Field::Scalar(ref scalar) => {
let wrapper = scalar.debug(quote!(ScalarWrapper));
quote! {
{
#wrapper
ScalarWrapper(&#ident)
}
}
}
Field::Map(ref map) => {
let wrapper = map.debug(quote!(MapWrapper));
quote! {
{
#wrapper
MapWrapper(&#ident)
}
}
}
_ => quote!(&#ident),
}
}
pub fn methods(&self, ident: &TokenStream) -> Option<TokenStream> {
match *self {
Field::Scalar(ref scalar) => scalar.methods(ident),
Field::Map(ref map) => map.methods(ident),
_ => None,
}
}
}
#[derive(Clone, Copy, PartialEq, Eq)]
pub enum Label {
/// An optional field.
Optional,
/// A required field.
Required,
/// A repeated field.
Repeated,
}
impl Label {
fn as_str(self) -> &'static str {
match self {
Label::Optional => "optional",
Label::Required => "required",
Label::Repeated => "repeated",
}
}
fn variants() -> slice::Iter<'static, Label> {
const VARIANTS: &[Label] = &[Label::Optional, Label::Required, Label::Repeated];
VARIANTS.iter()
}
/// Parses a string into a field label.
/// If the string doesn't match a field label, `None` is returned.
fn from_attr(attr: &Meta) -> Option<Label> {
if let Meta::Path(ref path) = *attr {
for &label in Label::variants() {
if path.is_ident(label.as_str()) {
return Some(label);
}
}
}
None
}
}
impl fmt::Debug for Label {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(self.as_str())
}
}
impl fmt::Display for Label {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(self.as_str())
}
}
/// Get the items belonging to the 'prost' list attribute, e.g. `#[prost(foo, bar="baz")]`.
fn prost_attrs(attrs: Vec<Attribute>) -> Result<Vec<Meta>, Error> {
let mut result = Vec::new();
for attr in attrs.iter() {
if let Meta::List(meta_list) = &attr.meta {
if meta_list.path.is_ident("prost") {
result.extend(
meta_list
.parse_args_with(Punctuated::<Meta, Token![,]>::parse_terminated)?
.into_iter(),
)
}
}
}
Ok(result)
}
pub fn set_option<T>(option: &mut Option<T>, value: T, message: &str) -> Result<(), Error>
where
T: fmt::Debug,
{
if let Some(ref existing) = *option {
bail!("{}: {:?} and {:?}", message, existing, value);
}
*option = Some(value);
Ok(())
}
pub fn set_bool(b: &mut bool, message: &str) -> Result<(), Error> {
if *b {
bail!("{}", message);
} else {
*b = true;
Ok(())
}
}
/// Unpacks an attribute into a (key, boolean) pair, returning the boolean value.
/// If the key doesn't match the attribute, `None` is returned.
fn bool_attr(key: &str, attr: &Meta) -> Result<Option<bool>, Error> {
if !attr.path().is_ident(key) {
return Ok(None);
}
match *attr {
Meta::Path(..) => Ok(Some(true)),
Meta::List(ref meta_list) => Ok(Some(meta_list.parse_args::<LitBool>()?.value())),
Meta::NameValue(MetaNameValue {
value:
Expr::Lit(ExprLit {
lit: Lit::Str(ref lit),
..
}),
..
}) => lit
.value()
.parse::<bool>()
.map_err(Error::from)
.map(Option::Some),
Meta::NameValue(MetaNameValue {
value:
Expr::Lit(ExprLit {
lit: Lit::Bool(LitBool { value, .. }),
..
}),
..
}) => Ok(Some(value)),
_ => bail!("invalid {} attribute", key),
}
}
/// Checks if an attribute matches a word.
fn word_attr(key: &str, attr: &Meta) -> bool {
if let Meta::Path(ref path) = *attr {
path.is_ident(key)
} else {
false
}
}
pub(super) fn tag_attr(attr: &Meta) -> Result<Option<u32>, Error> {
if !attr.path().is_ident("tag") {
return Ok(None);
}
match *attr {
Meta::List(ref meta_list) => Ok(Some(meta_list.parse_args::<LitInt>()?.base10_parse()?)),
Meta::NameValue(MetaNameValue {
value: Expr::Lit(ref expr),
..
}) => match expr.lit {
Lit::Str(ref lit) => lit
.value()
.parse::<u32>()
.map_err(Error::from)
.map(Option::Some),
Lit::Int(ref lit) => Ok(Some(lit.base10_parse()?)),
_ => bail!("invalid tag attribute: {:?}", attr),
},
_ => bail!("invalid tag attribute: {:?}", attr),
}
}
fn tags_attr(attr: &Meta) -> Result<Option<Vec<u32>>, Error> {
if !attr.path().is_ident("tags") {
return Ok(None);
}
match *attr {
Meta::List(ref meta_list) => Ok(Some(
meta_list
.parse_args_with(Punctuated::<LitInt, Token![,]>::parse_terminated)?
.iter()
.map(LitInt::base10_parse)
.collect::<Result<Vec<_>, _>>()?,
)),
Meta::NameValue(MetaNameValue {
value:
Expr::Lit(ExprLit {
lit: Lit::Str(ref lit),
..
}),
..
}) => lit
.value()
.split(',')
.map(|s| s.trim().parse::<u32>().map_err(Error::from))
.collect::<Result<Vec<u32>, _>>()
.map(Some),
_ => bail!("invalid tag attribute: {:?}", attr),
}
}
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