tor_netdoc/parse2/traits.rs
1//! Core model for netdoc parsing
2
3use super::*;
4
5/// A document or section that can be parsed
6///
7/// Normally [derived](derive_deftly_template_NetdocParseable).
8pub trait NetdocParseable: Sized {
9 /// Document type for errors, normally its intro keyword
10 fn doctype_for_error() -> &'static str;
11
12 /// Is `Keyword` an intro Item Keyword for this kind of document?
13 ///
14 /// This is used with 1-keyword lookahead, to allow us to push or pop
15 /// the parsing state into or out of a sub-document.
16 ///
17 /// For signatures sections, this should report *every* recognised keyword.
18 fn is_intro_item_keyword(kw: KeywordRef<'_>) -> bool;
19
20 /// Parse the document from a stream of Items
21 ///
22 /// Should stop before reading any keyword matching `stop_at`.
23 /// (Except, right at the start.)
24 ///
25 /// Should also stop before reading a 2nd intro keyword,
26 /// so that successive calls to this function can parse
27 /// successive sub-documents of this kind.
28 ///
29 /// Otherwise, should continue until EOF.
30 ///
31 /// Must check whether the first item is this document's `is_intro_item_keyword`,
32 /// and error if not.
33 fn from_items(input: &mut ItemStream<'_>, stop_at: stop_at!()) -> Result<Self, ErrorProblem>;
34}
35
36/// A collection of fields that can be parsed within a section
37///
38/// None of the items can be structural.
39///
40/// Normally [derived](derive_deftly_template_NetdocParseableFields).
41pub trait NetdocParseableFields: Sized {
42 /// The partially-parsed set of items.
43 type Accumulator: Sized + Debug + Send + Sync + 'static;
44
45 /// Is this one of the keywords in this struct
46 fn is_item_keyword(kw: KeywordRef<'_>) -> bool;
47
48 /// Accumulate an item in this struct
49 ///
50 /// # Panics
51 ///
52 /// The caller must have first checked the `item`'s keyword with `is_item_keyword`.
53 /// If this *isn't* an item for this structure, may panic.
54 fn accumulate_item(acc: &mut Self::Accumulator, item: UnparsedItem<'_>) -> Result<(), EP>;
55
56 /// Finish
57 ///
58 /// Resolves the `Accumulator` into the output type.
59 /// Generally, this means throwing an error if expected fields were not present.
60 fn finish(acc: Self::Accumulator) -> Result<Self, EP>;
61}
62
63/// A network document with (unverified) signatures
64///
65/// Typically implemented automatically, for `FooSigned` structs, as defined by
66/// [`#[derive_deftly(NetdocSigned)]`](derive_deftly_template_NetdocSigned).
67pub trait NetdocSigned {
68 /// The body, ie not including the signatures
69 type Body: Sized;
70 /// The signatures (the whole signature section)
71 type Signatures: Sized;
72
73 /// Inspect the document (and its signatures)
74 ///
75 /// # Security hazard
76 ///
77 /// The signature has not been verified, so the returned data must not be trusted.
78 fn inspect_unverified(&self) -> (&Self::Body, &Self::Signatures);
79
80 /// Obtain the actual document (and signatures), without verifying
81 ///
82 /// # Security hazard
83 ///
84 /// The signature has not been verified, so the returned data must not be trusted.
85 fn unwrap_unverified(self) -> (Self::Body, Self::Signatures);
86
87 /// Construct a new `NetdocSigned` from a body and signatures
88 ///
89 /// (Called by code generated by `#[derive_deftly(NetdocSigned)]`.)
90 fn from_parts(body: Self::Body, signatures: Self::Signatures) -> Self;
91}
92
93/// An item (value) that can appear in a netdoc
94///
95/// This is the type `T` of a field `item: T` in a netdoc type.
96///
97/// An implementation is provided for tuples of `ItemArgumentParseable`,
98/// which parses each argument in turn,
99/// ignores additional arguments,
100/// and rejects any Object.
101///
102/// Typically derived with
103/// [`#[derive_deftly(ItemValueParseable)]`](derive_deftly_template_ItemValueParseable).
104///
105/// Signature items are special, and implement [`SignatureItemParseable`] instead.
106pub trait ItemValueParseable: Sized {
107 /// Parse the item's value
108 fn from_unparsed(item: UnparsedItem<'_>) -> Result<Self, ErrorProblem>;
109}
110
111/// An (individual) argument that can appear in a netdoc
112///
113/// An implementations is provided for **`T: FromStr`**,
114/// which expects a single argument and passes it to `FromStr`.
115///
116/// For netdoc arguments whose specified syntax spans multiple space-separated words,
117/// use a manual implementation or a wrapper type.
118pub trait ItemArgumentParseable: Sized {
119 /// Parse the argument
120 fn from_args<'s>(args: &mut ArgumentStream<'s>) -> Result<Self, ArgumentError>;
121}
122
123/// A possibly-optional Object value that can appear in netdoc
124///
125/// Implemented for `Option`, so that `field: Option<ObjectValue>`
126/// allows parsing an optional object.
127pub trait ItemObjectParseable: Sized {
128 /// Check that the Label is right
129 fn check_label(label: &str) -> Result<(), ErrorProblem>;
130
131 /// Convert the bytes of the Object (which was present) into the actual value
132 ///
133 /// `input` has been base64-decoded.
134 fn from_bytes(input: &[u8]) -> Result<Self, ErrorProblem>;
135}
136
137//---------- provided blanket impls ----------
138
139impl<T: NormalItemArgument> ItemArgumentParseable for T {
140 fn from_args<'s>(args: &mut ArgumentStream<'s>) -> Result<Self, AE> {
141 let v = args
142 .next()
143 .ok_or(AE::Missing)?
144 .parse()
145 .map_err(|_e| AE::Missing)?;
146 Ok(v)
147 }
148}
149
150impl<T: ItemValueParseable> ItemValueParseable for Arc<T> {
151 fn from_unparsed(item: UnparsedItem<'_>) -> Result<Self, ErrorProblem> {
152 T::from_unparsed(item).map(Arc::new)
153 }
154}
155
156impl<T: NetdocParseable> NetdocParseable for Arc<T> {
157 fn doctype_for_error() -> &'static str {
158 T::doctype_for_error()
159 }
160 fn is_intro_item_keyword(kw: KeywordRef<'_>) -> bool {
161 T::is_intro_item_keyword(kw)
162 }
163 fn from_items(input: &mut ItemStream<'_>, stop_at: stop_at!()) -> Result<Self, EP> {
164 T::from_items(input, stop_at).map(Arc::new)
165 }
166}
167impl<T: NetdocParseableFields> NetdocParseableFields for Arc<T> {
168 type Accumulator = T::Accumulator;
169 fn is_item_keyword(kw: KeywordRef<'_>) -> bool {
170 T::is_item_keyword(kw)
171 }
172 fn accumulate_item(acc: &mut Self::Accumulator, item: UnparsedItem<'_>) -> Result<(), EP> {
173 T::accumulate_item(acc, item)
174 }
175 fn finish(acc: Self::Accumulator) -> Result<Self, EP> {
176 T::finish(acc).map(Arc::new)
177 }
178}
179
180/// implement [`ItemValueParseable`] for a particular tuple size
181macro_rules! item_value_parseable_for_tuple {
182 { $($i:literal)* } => { paste! {
183 impl< $( [<T$i>]: ItemArgumentParseable, )* >
184 ItemValueParseable for ( $( [<T$i>], )* )
185 {
186 fn from_unparsed(
187 #[allow(unused_mut)]
188 mut item: UnparsedItem<'_>,
189 ) -> Result<Self, ErrorProblem> {
190 let r = ( $(
191 <[<T$i>] as ItemArgumentParseable>::from_args(
192 item.args_mut(),
193 ).map_err(item.args().error_handler(stringify!($i)))?,
194 )* );
195 item.check_no_object()?;
196 Ok(r)
197 }
198 }
199 } }
200}
201
202item_value_parseable_for_tuple! {}
203item_value_parseable_for_tuple! { 0 }
204item_value_parseable_for_tuple! { 0 1 }
205item_value_parseable_for_tuple! { 0 1 2 }
206item_value_parseable_for_tuple! { 0 1 2 3 }
207item_value_parseable_for_tuple! { 0 1 2 3 4 }
208item_value_parseable_for_tuple! { 0 1 2 3 4 5 }
209item_value_parseable_for_tuple! { 0 1 2 3 4 5 6 }
210item_value_parseable_for_tuple! { 0 1 2 3 4 5 6 7 }
211item_value_parseable_for_tuple! { 0 1 2 3 4 5 6 7 8 }
212item_value_parseable_for_tuple! { 0 1 2 3 4 5 6 7 8 9 }