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Fix patterns of provide_context gets panicked #37

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Merged
merged 1 commit into from
Mar 19, 2018
Merged

Fix patterns of provide_context gets panicked #37

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25 changes: 24 additions & 1 deletion src/grapheme.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -360,7 +360,10 @@ impl GraphemeCursor {
match self.state {
GraphemeState::Regional => self.handle_regional(chunk, chunk_start),
GraphemeState::Emoji => self.handle_emoji(chunk, chunk_start),
_ => panic!("invalid state")
_ => if self.cat_before.is_none() && self.offset == chunk.len() + chunk_start {
let ch = chunk.chars().rev().next().unwrap();
self.cat_before = Some(gr::grapheme_category(ch));
},
}
}

Expand Down Expand Up @@ -406,6 +409,7 @@ impl GraphemeCursor {
return;
}
self.pre_context_offset = Some(chunk_start);
self.state = GraphemeState::Regional;
}

fn handle_emoji(&mut self, chunk: &str, chunk_start: usize) {
Expand All @@ -428,6 +432,7 @@ impl GraphemeCursor {
return;
}
self.pre_context_offset = Some(chunk_start);
self.state = GraphemeState::Emoji;
}

/// Determine whether the current cursor location is a grapheme cluster boundary.
Expand Down Expand Up @@ -659,3 +664,21 @@ impl GraphemeCursor {
}
}
}

#[test]
fn test_grapheme_cursor_ris_precontext() {
let s = "\u{1f1fa}\u{1f1f8}\u{1f1fa}\u{1f1f8}\u{1f1fa}\u{1f1f8}";
let mut c = GraphemeCursor::new(8, s.len(), true);
assert_eq!(c.is_boundary(&s[4..], 4), Err(GraphemeIncomplete::PreContext(4)));
c.provide_context(&s[..4], 0);
assert_eq!(c.is_boundary(&s[4..], 4), Ok(true));
}

#[test]
fn test_grapheme_cursor_chunk_start_require_precontext() {
let s = "\r\n";
let mut c = GraphemeCursor::new(1, s.len(), true);
assert_eq!(c.is_boundary(&s[1..], 1), Err(GraphemeIncomplete::PreContext(1)));
c.provide_context(&s[..1], 0);
assert_eq!(c.is_boundary(&s[1..], 1), Ok(false));
}