tokens: add a more advanced tokens parser

Signed-off-by: William Casarin <jb55@jb55.com>

crates/notedeck_columns/src/storage/mod.rs

@@ -5,4 +5,7 @@ mod token_parser;
 pub use decks::{load_decks_cache, save_decks_cache, DECKS_CACHE_FILE};
 pub use migration::{deserialize_columns, COLUMNS_FILE};
 
-pub use token_parser::{ParseError, TokenParser, TokenSerializable, TokenWriter};
+pub use token_parser::{
+    ParseError, Payload, Token, TokenAlternatives, TokenParser, TokenPayload, TokenSerializable,
+    TokenWriter, UnexpectedToken,
+};

crates/notedeck_columns/src/storage/token_parser.rs

@@ -1,5 +1,5 @@
 use crate::timeline::kind::PubkeySource;
-use enostr::Pubkey;
+use enostr::{NoteId, Pubkey};
 
 #[derive(Debug, Clone)]
 pub struct UnexpectedToken<'fnd, 'exp> {
@@ -7,6 +7,251 @@ pub struct UnexpectedToken<'fnd, 'exp> {
     pub found: &'fnd str,
 }
 
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum TokenPayload {
+    PubkeySource,
+    Pubkey,
+    NoteId,
+}
+
+pub struct TokenAlternatives {
+    /// This is the preferred token. It should be serialized this way
+    preferred: &'static str,
+
+    /// These are deprecated tokens that should still be handled and parsed
+    deprecated: &'static [&'static str],
+}
+
+impl TokenAlternatives {
+    pub const fn new(preferred: &'static str, deprecated: &'static [&'static str]) -> Self {
+        Self {
+            preferred,
+            deprecated,
+        }
+    }
+}
+
+/// Token is a unified serialization helper. By specifying a list of
+/// tokens for each thing you want to parse, you can type-safely parse
+/// and serialize things
+pub enum Token {
+    /// A simple identifier
+    Identifier(&'static str),
+
+    /// There are multiple ways to parse this identifier
+    Alternatives(TokenAlternatives),
+
+    /// Different payload types, pubkeys etc
+    Payload(TokenPayload),
+}
+
+#[derive(Debug, Clone)]
+pub enum Payload {
+    PubkeySource(PubkeySource),
+    Pubkey(Pubkey),
+    NoteId(NoteId),
+}
+
+impl Payload {
+    pub fn token_payload(&self) -> TokenPayload {
+        match self {
+            Payload::PubkeySource(_) => TokenPayload::PubkeySource,
+            Payload::Pubkey(_) => TokenPayload::Pubkey,
+            Payload::NoteId(_) => TokenPayload::NoteId,
+        }
+    }
+
+    pub fn parse_note_id(payload: Option<Payload>) -> Result<NoteId, ParseError<'static>> {
+        payload
+            .and_then(|p| p.get_note_id().cloned())
+            .ok_or(ParseError::ExpectedPayload(TokenPayload::NoteId))
+    }
+
+    pub fn parse_pubkey(payload: Option<Payload>) -> Result<Pubkey, ParseError<'static>> {
+        payload
+            .and_then(|p| p.get_pubkey().cloned())
+            .ok_or(ParseError::ExpectedPayload(TokenPayload::Pubkey))
+    }
+
+    pub fn parse_pubkey_source(
+        payload: Option<Payload>,
+    ) -> Result<PubkeySource, ParseError<'static>> {
+        payload
+            .and_then(|p| p.get_pubkey_source().cloned())
+            .ok_or(ParseError::ExpectedPayload(TokenPayload::Pubkey))
+    }
+
+    pub fn parse<'a>(
+        expected: TokenPayload,
+        parser: &mut TokenParser<'a>,
+    ) -> Result<Self, ParseError<'a>> {
+        match expected {
+            TokenPayload::PubkeySource => Ok(Payload::pubkey_source(
+                PubkeySource::parse_from_tokens(parser)?,
+            )),
+            TokenPayload::Pubkey => {
+                let pubkey = parser.try_parse(|p| {
+                    let hex = p.pull_token()?;
+                    Pubkey::from_hex(hex).map_err(|_| ParseError::HexDecodeFailed)
+                })?;
+
+                Ok(Payload::pubkey(pubkey))
+            }
+            TokenPayload::NoteId => {
+                let note_id = parser.try_parse(|p| {
+                    let hex = p.pull_token()?;
+                    NoteId::from_hex(hex).map_err(|_| ParseError::HexDecodeFailed)
+                })?;
+
+                Ok(Payload::note_id(note_id))
+            }
+        }
+    }
+
+    pub fn pubkey(pubkey: Pubkey) -> Self {
+        Self::Pubkey(pubkey)
+    }
+
+    pub fn pubkey_source(pubkey_src: PubkeySource) -> Self {
+        Self::PubkeySource(pubkey_src)
+    }
+
+    pub fn note_id(note_id: NoteId) -> Self {
+        Self::NoteId(note_id)
+    }
+
+    pub fn get_pubkey(&self) -> Option<&Pubkey> {
+        if let Self::Pubkey(pubkey) = self {
+            Some(pubkey)
+        } else {
+            None
+        }
+    }
+
+    pub fn get_pubkey_source(&self) -> Option<&PubkeySource> {
+        if let Self::PubkeySource(pk_src) = self {
+            Some(pk_src)
+        } else {
+            None
+        }
+    }
+
+    pub fn get_note_id(&self) -> Option<&NoteId> {
+        if let Self::NoteId(note_id) = self {
+            Some(note_id)
+        } else {
+            None
+        }
+    }
+}
+
+impl Token {
+    pub fn parse<'a>(
+        &self,
+        parser: &mut TokenParser<'a>,
+    ) -> Result<Option<Payload>, ParseError<'a>> {
+        match self {
+            Token::Identifier(s) => {
+                parser.parse_token(s)?;
+                Ok(None)
+            }
+
+            Token::Payload(payload) => {
+                let payload = Payload::parse(*payload, parser)?;
+                Ok(Some(payload))
+            }
+
+            Token::Alternatives(alts) => {
+                if parser.try_parse(|p| p.parse_token(alts.preferred)).is_ok() {
+                    return Ok(None);
+                }
+
+                for token in alts.deprecated {
+                    if parser.try_parse(|p| p.parse_token(token)).is_ok() {
+                        return Ok(None);
+                    }
+                }
+
+                Err(ParseError::AltAllFailed)
+            }
+        }
+    }
+
+    /// Parse all of the tokens in sequence, ensuring that we extract a payload
+    /// if we find one. This only handles a single payload, if you need more,
+    /// then use a custom parser
+    pub fn parse_all<'a>(
+        parser: &mut TokenParser<'a>,
+        tokens: &[Token],
+    ) -> Result<Option<Payload>, ParseError<'a>> {
+        parser.try_parse(|p| {
+            let mut payload: Option<Payload> = None;
+            for token in tokens {
+                if let Some(pl) = token.parse(p)? {
+                    payload = Some(pl);
+                }
+            }
+
+            Ok(payload)
+        })
+    }
+
+    pub fn serialize_all(writer: &mut TokenWriter, tokens: &[Token], payload: Option<&Payload>) {
+        for token in tokens {
+            token.serialize(writer, payload)
+        }
+    }
+
+    pub fn serialize(&self, writer: &mut TokenWriter, payload: Option<&Payload>) {
+        match self {
+            Token::Identifier(s) => writer.write_token(s),
+            Token::Alternatives(alts) => writer.write_token(alts.preferred),
+            Token::Payload(token_payload) => match token_payload {
+                TokenPayload::PubkeySource => {
+                    payload
+                        .and_then(|p| p.get_pubkey_source())
+                        .expect("expected pubkey payload")
+                        .serialize_tokens(writer);
+                }
+
+                TokenPayload::Pubkey => {
+                    let pubkey = payload
+                        .and_then(|p| p.get_pubkey())
+                        .expect("expected note_id payload");
+                    writer.write_token(&hex::encode(pubkey.bytes()));
+                }
+
+                TokenPayload::NoteId => {
+                    let note_id = payload
+                        .and_then(|p| p.get_note_id())
+                        .expect("expected note_id payload");
+                    writer.write_token(&hex::encode(note_id.bytes()));
+                }
+            },
+        }
+    }
+
+    pub const fn id(s: &'static str) -> Self {
+        Token::Identifier(s)
+    }
+
+    pub const fn alts(primary: &'static str, deprecated: &'static [&'static str]) -> Self {
+        Token::Alternatives(TokenAlternatives::new(primary, deprecated))
+    }
+
+    pub const fn pubkey() -> Self {
+        Token::Payload(TokenPayload::Pubkey)
+    }
+
+    pub const fn pubkey_source() -> Self {
+        Token::Payload(TokenPayload::PubkeySource)
+    }
+
+    pub const fn note_id() -> Self {
+        Token::Payload(TokenPayload::NoteId)
+    }
+}
+
 #[derive(Debug, Clone)]
 pub enum ParseError<'a> {
     /// Not done parsing yet
@@ -18,6 +263,11 @@ pub enum ParseError<'a> {
     /// There was some issue decoding the data
     DecodeFailed,
 
+    /// There was some issue decoding the data
+    ExpectedPayload(TokenPayload),
+
+    HexDecodeFailed,
+
     /// We encountered an unexpected token
     UnexpectedToken(UnexpectedToken<'a, 'static>),
 
@@ -122,6 +372,18 @@ impl<'a> TokenParser<'a> {
         Self { tokens, index }
     }
 
+    pub fn peek_parse_token(&mut self, expected: &'static str) -> Result<&'a str, ParseError<'a>> {
+        let found = self.peek_token()?;
+        if found == expected {
+            Ok(found)
+        } else {
+            Err(ParseError::UnexpectedToken(UnexpectedToken {
+                expected,
+                found,
+            }))
+        }
+    }
+
     pub fn parse_token(&mut self, expected: &'static str) -> Result<&'a str, ParseError<'a>> {
         let found = self.pull_token()?;
         if found == expected {
@@ -154,6 +416,23 @@ impl<'a> TokenParser<'a> {
         }
     }
 
+    /// Attempt to parse something, backtrack if we fail.
+    pub fn try_parse<R>(
+        &mut self,
+        parse_fn: impl FnOnce(&mut Self) -> Result<R, ParseError<'a>>,
+    ) -> Result<R, ParseError<'a>> {
+        let start = self.index;
+        let result = parse_fn(self);
+
+        // If the parser closure fails, revert the index
+        if result.is_err() {
+            self.index = start;
+            result
+        } else {
+            result
+        }
+    }
+
     pub fn pull_token(&mut self) -> Result<&'a str, ParseError<'a>> {
         let token = self
             .tokens
@@ -172,6 +451,13 @@ impl<'a> TokenParser<'a> {
         self.index -= 1;
     }
 
+    pub fn peek_token(&self) -> Result<&'a str, ParseError<'a>> {
+        self.tokens()
+            .first()
+            .ok_or(ParseError::DecodeFailed)
+            .copied()
+    }
+
     #[inline]
     pub fn tokens(&self) -> &'a [&'a str] {
         let min_index = self.index.min(self.tokens.len());
@@ -187,8 +473,8 @@ impl<'a> TokenParser<'a> {
 pub trait TokenSerializable: Sized {
     /// Return a list of serialization plans for a type. We do this for
     /// type safety and assume constructing these types are lightweight
-    fn parse<'a>(parser: &mut TokenParser<'a>) -> Result<Self, ParseError<'a>>;
-    fn serialize(&self, writer: &mut TokenWriter);
+    fn parse_from_tokens<'a>(parser: &mut TokenParser<'a>) -> Result<Self, ParseError<'a>>;
+    fn serialize_tokens(&self, writer: &mut TokenWriter);
 }
 
 #[cfg(test)]
@@ -204,9 +490,9 @@ mod tests {
             let data = &data_str.split(":").collect::<Vec<&str>>();
             let mut token_writer = TokenWriter::default();
             let mut parser = TokenParser::new(&data);
-            let parsed = AddColumnRoute::parse(&mut parser).unwrap();
+            let parsed = AddColumnRoute::parse_from_tokens(&mut parser).unwrap();
             let expected = AddColumnRoute::Algo(AddAlgoRoute::LastPerPubkey);
-            parsed.serialize(&mut token_writer);
+            parsed.serialize_tokens(&mut token_writer);
             assert_eq!(expected, parsed);
             assert_eq!(token_writer.str(), data_str);
         }
@@ -216,9 +502,9 @@ mod tests {
             let mut token_writer = TokenWriter::default();
             let data: &[&str] = &[data_str];
             let mut parser = TokenParser::new(data);
-            let parsed = AddColumnRoute::parse(&mut parser).unwrap();
+            let parsed = AddColumnRoute::parse_from_tokens(&mut parser).unwrap();
             let expected = AddColumnRoute::Base;
-            parsed.serialize(&mut token_writer);
+            parsed.serialize_tokens(&mut token_writer);
             assert_eq!(expected, parsed);
             assert_eq!(token_writer.str(), data_str);
         }

crates/notedeck_columns/src/ui/add_column.rs

@@ -104,20 +104,23 @@ impl AddColumnRoute {
             Self::ExternalIndividual => &["column", "external_individual_selection"],
             Self::Hashtag => &["column", "hashtag"],
             Self::Algo(AddAlgoRoute::Base) => &["column", "algo_selection"],
-            Self::Algo(AddAlgoRoute::LastPerPubkey) => &["column", "algo_selection", "last_per_pubkey"],
-            // NOTE!!! When adding to this, update the parser for TokenSerializable below
+            Self::Algo(AddAlgoRoute::LastPerPubkey) => {
+                &["column", "algo_selection", "last_per_pubkey"]
+            } // NOTE!!! When adding to this, update the parser for TokenSerializable below
         }
     }
 }
 
 impl TokenSerializable for AddColumnRoute {
-    fn serialize(&self, writer: &mut TokenWriter) {
+    fn serialize_tokens(&self, writer: &mut TokenWriter) {
         for token in self.tokens() {
             writer.write_token(token);
         }
     }
 
-    fn parse<'a>(parser: &mut TokenParser<'a>) -> Result<Self, ParseError<'a>> {
+    fn parse_from_tokens<'a>(parser: &mut TokenParser<'a>) -> Result<Self, ParseError<'a>> {
+        parser.peek_parse_token("column")?;
+
         TokenParser::alt(
             parser,
             &[