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use core::range::Range;
use crate::{
Error, ErrorKind, Result,
tokens::{Token, TokenStream, TokenWithContext},
traverse::{Visitor, parse_tokens_at_depth, validate_start_of_value},
};
#[derive(Debug, PartialEq, Eq, Clone)]
enum ObjectState {
Open,
KeyOrEnd {
open_ctx: TokenWithContext,
last_pair: Option<Range<usize>>,
},
Key {
comma_ctx: TokenWithContext,
open_ctx: TokenWithContext,
},
Colon {
key_ctx: TokenWithContext,
open_ctx: TokenWithContext,
},
Value {
colon_ctx: TokenWithContext,
open_ctx: TokenWithContext,
},
End(Range<usize>),
}
impl ObjectState {
fn process<'a>(
self,
tokens: &mut TokenStream<'a>,
text: &'a str,
visitor: &mut impl Visitor<'a>,
depth: usize,
) -> Result<Self> {
let res = match self {
ObjectState::Open => match tokens.next_token()? {
Some(
ctx @ TokenWithContext {
token: Token::OpenCurlyBrace,
..
},
) => {
visitor.on_object_open(ctx.range);
ObjectState::KeyOrEnd {
open_ctx: ctx,
last_pair: None,
}
}
maybe_token => {
return Err(Error::from_maybe_token_with_context(
|tok| ErrorKind::ExpectedOpenBrace {
expected: '{'.into(),
context: None,
found: tok,
},
maybe_token,
text,
));
}
},
ObjectState::KeyOrEnd {
open_ctx,
last_pair,
} => match (last_pair, tokens.next_token()?) {
(
_,
Some(
ctx @ TokenWithContext {
token: Token::ClosedCurlyBrace,
..
},
),
) => {
visitor.on_object_close(ctx.range);
ObjectState::End(open_ctx.range.start..ctx.range.end)
}
(
Some(_),
Some(
comma_ctx @ TokenWithContext {
token: Token::Comma,
..
},
),
) => {
visitor.on_item_delim();
ObjectState::Key {
comma_ctx,
open_ctx,
}
}
(
None,
Some(
key_ctx @ TokenWithContext {
token: Token::String,
..
},
),
) => {
let body = key_ctx.content_range();
visitor.on_object_key(body, &text[body]);
ObjectState::Colon { key_ctx, open_ctx }
}
(Some(pair_span), maybe_token) => {
return Err(Error::from_maybe_token_with_context(
|tok| ErrorKind::ExpectedCommaOrClosedCurlyBrace {
range: pair_span,
open_ctx,
found: tok,
},
maybe_token,
text,
));
}
(None, maybe_token) => {
return Err(Error::from_maybe_token_with_context(
|tok| {
ErrorKind::expected_entry_or_closed_delimiter(open_ctx, tok)
.expect("object should open with a curly brace")
},
maybe_token,
text,
));
}
},
ObjectState::Key {
comma_ctx,
open_ctx,
} => match tokens.next_token()? {
Some(
key_ctx @ TokenWithContext {
token: Token::String,
..
},
) => {
let body = key_ctx.content_range();
visitor.on_object_key(body, &text[body]);
ObjectState::Colon { key_ctx, open_ctx }
}
maybe_token => {
return Err(Error::from_maybe_token_with_context(
|tok| ErrorKind::ExpectedKey(comma_ctx, tok),
maybe_token,
text,
));
}
},
ObjectState::Colon { key_ctx, open_ctx } => match tokens.next_token()? {
Some(
colon_ctx @ TokenWithContext {
token: Token::Colon,
..
},
) => {
visitor.on_object_key_val_delim();
ObjectState::Value {
colon_ctx,
open_ctx,
}
}
maybe_token => {
return Err(Error::from_maybe_token_with_context(
|tok| ErrorKind::ExpectedColon(key_ctx, tok),
maybe_token,
text,
));
}
},
ObjectState::Value {
colon_ctx,
open_ctx,
} => {
validate_start_of_value(text, colon_ctx, tokens.peek_token()?.copied())?;
let value_range = parse_tokens_at_depth(tokens, text, false, visitor, depth + 1)?;
ObjectState::KeyOrEnd {
open_ctx,
last_pair: Some(colon_ctx.range.start..value_range.end),
}
}
ObjectState::End(range) => ObjectState::End(range),
};
Ok(res)
}
}
pub fn parse_object<'a>(
tokens: &mut TokenStream<'a>,
text: &'a str,
depth: usize,
visitor: &mut impl Visitor<'a>,
) -> Result<Range<usize>> {
let mut state = ObjectState::Open;
loop {
state = state.process(tokens, text, visitor, depth)?;
if let ObjectState::End(range) = state {
break Ok(range);
}
}
}