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|
use super::source_code::{extract_range, LineColumn, Range};
use anyhow::{Context, Result};
use proc_macro2::{Span, TokenStream, TokenTree};
use syn::spanned::Spanned;
use syn::visit::Visit;
use syn::{Macro, PathSegment};
#[derive(Debug)]
struct MacroVisitor {
found: Option<(TokenStream, Macro)>,
line: usize,
macro_name: String,
}
impl<'ast> Visit<'ast> for MacroVisitor {
fn visit_macro(&mut self, m: &'ast Macro) {
let last_path_segment = m.path.segments.last();
if let Some(PathSegment { ident, .. }) = last_path_segment {
if ident == &self.macro_name && ident.span().start().line == self.line {
self.found.replace((m.tokens.to_owned(), m.to_owned()));
}
}
}
}
/// Find the Range containing the space where snapshot literal needs to be written.
///
/// If a literal already exists, it will return the range of the existing string literal.
///
/// some_macro!(blah);
/// ^
/// |
/// 0 length range of the position where
/// new snapshot needs to be written
///
/// Otherwise, if the snapshot literal is there, return its range
///
/// some_macro(blah, "hello")
/// ^ ^
/// | |
/// range
pub fn find_snapshot_literal_range<S: Into<String>>(
file_content: &str,
macro_name: S,
line_num: usize,
literal_exists: bool,
) -> Result<Range> {
let syntax = syn::parse_file(file_content).expect("Unable to parse file");
let macro_name = macro_name.into();
let mut macro_visitor = MacroVisitor {
found: None,
line: line_num,
macro_name: macro_name.clone(),
};
macro_visitor.visit_file(&syntax);
let (tt, macro_node) = macro_visitor.found.with_context(|| {
format!(
"Failed to find a macro call AST node with macro name `{}!()`.\nThis macro was called on line `{}`\n\n",
¯o_name, line_num
)
})?;
if literal_exists {
let literal = tt.into_iter().last();
if let Some(TokenTree::Literal(literal)) = literal {
Ok(Range {
start: LineColumn {
line: literal.span().start().line,
// columns might be 0 based? i'm not sure
column: literal.span().start().column + 1,
},
end: LineColumn {
line: literal.span().end().line,
column: literal.span().end().column + 1,
},
})
} else {
let macro_range = syn_span_to_range(macro_node.span());
let macro_code = extract_range(file_content, ¯o_range);
anyhow::bail!(
r#"
Failed to extract a snapshot literal from a snapshot macro call.
Snapshot literal must be the last argument to a macro call and must be a string literal. e.g.
assert_matches_inline_snapshot!(12345, "12345");
^ ^
| |
snapshot literal
Given macro call:
```
{}
```
"#,
macro_code,
)
}
} else {
let last = tt.into_iter().last().expect("must have last tokentree");
let span = last.span();
Ok(Range {
start: LineColumn {
line: span.end().line,
column: span.end().column + 1,
},
end: LineColumn {
line: span.end().line,
column: span.end().column + 1,
},
})
}
}
/// Convert proc_macro2 Span struct to local Range struct, which indexes
/// for Lines and Columns starting from 1 and not 0
fn syn_span_to_range(span: Span) -> Range {
Range {
start: LineColumn {
line: span.start().line,
column: span.start().column + 1,
},
end: LineColumn {
line: span.end().line,
column: span.end().column + 1,
},
}
}
#[cfg(test)]
mod tests {
use super::*;
const SOURCE: &str = r##" // 1
fn main() { // 2
let hello = "world"; // 3
random_macro!(hello); // 4
hello_macro!(stuff, "literal"); // 5
wrong_macro!(stuff, not_a_literal); // 6
}
"##;
#[test]
fn no_literal() -> Result<()> {
let range = find_snapshot_literal_range(SOURCE, "random_macro", 4, false)?;
k9::assert_equal!(&range.start, &range.end);
k9::snapshot!(
format!("{:?}", range),
r##"Range { start: LineColumn { line: 4, column: 24 }, end: LineColumn { line: 4, column: 24 } }"##
);
Ok(())
}
#[test]
fn literal() -> Result<()> {
let range = find_snapshot_literal_range(SOURCE, "hello_macro", 5, true)?;
k9::snapshot!(
format!("{:?}", range),
r##"Range { start: LineColumn { line: 5, column: 25 }, end: LineColumn { line: 5, column: 34 } }"##
);
Ok(())
}
#[test]
#[ignore = "the error stacktrace shows up in the snapshot and causes a mismatch"]
fn not_a_literal_error() {
let err = find_snapshot_literal_range(SOURCE, "wrong_macro", 6, true).unwrap_err();
k9::snapshot!(
format!("{:?}", err),
r#"
Failed to extract a snapshot literal from a snapshot macro call.
Snapshot literal must be the last argument to a macro call and must be a string literal. e.g.
assert_matches_inline_snapshot!(12345, "12345");
^ ^
| |
snapshot literal
Given macro call:
```
wrong_macro!(stuff, not_a_literal)
```
"#
);
}
}
|
