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Format code block in comment

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Closes #554.
Closes #1695.
This commit is contained in:
Seiichi Uchida 2017-12-24 23:40:53 +09:00
parent 939a6c5820
commit 27167cbbaa
3 changed files with 190 additions and 27 deletions
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74
src/comment.rs
View file

@ -318,41 +318,65 @@ fn rewrite_comment_inner(
let mut result = String::with_capacity(orig.len() * 2);
result.push_str(opener);
let mut code_block_buffer = String::with_capacity(128);
let mut is_prev_line_multi_line = false;
let mut inside_code_block = false;
let comment_line_separator = format!("\n{}{}", indent_str, line_start);
let join_code_block_with_comment_line_separator = |s: &str| {
let mut result = String::with_capacity(s.len() + 128);
let mut iter = s.lines().peekable();
while let Some(line) = iter.next() {
result.push_str(line);
result.push_str(match iter.peek() {
Some(ref next_line) if next_line.is_empty() => comment_line_separator.trim_right(),
Some(..) => &comment_line_separator,
None => "",
});
}
result
};
for (i, (line, has_leading_whitespace)) in lines.enumerate() {
let is_last = i == count_newlines(orig);
if result == opener {
let force_leading_whitespace = opener == "/* " && count_newlines(orig) == 0;
if !has_leading_whitespace && !force_leading_whitespace && result.ends_with(' ') {
result.pop();
}
if line.is_empty() {
continue;
}
} else if is_prev_line_multi_line && !line.is_empty() {
result.push(' ')
} else if is_last && !closer.is_empty() && line.is_empty() {
result.push('\n');
result.push_str(&indent_str);
} else {
result.push_str(&comment_line_separator);
if !has_leading_whitespace && result.ends_with(' ') {
result.pop();
}
}
if line.starts_with("```") {
inside_code_block = !inside_code_block;
}
if inside_code_block {
if line.is_empty() && result.ends_with(' ') {
result.pop();
} else {
if line.starts_with("```") {
inside_code_block = false;
result.push_str(&comment_line_separator);
let code_block = ::format_code_block(&code_block_buffer, config)
.unwrap_or_else(|| code_block_buffer.to_owned());
result.push_str(&join_code_block_with_comment_line_separator(&code_block));
code_block_buffer.clear();
result.push_str(&comment_line_separator);
result.push_str(line);
} else {
code_block_buffer.push_str(line);
code_block_buffer.push('\n');
}
continue;
} else {
inside_code_block = line.starts_with("```");
if result == opener {
let force_leading_whitespace = opener == "/* " && count_newlines(orig) == 0;
if !has_leading_whitespace && !force_leading_whitespace && result.ends_with(' ') {
result.pop();
}
if line.is_empty() {
continue;
}
} else if is_prev_line_multi_line && !line.is_empty() {
result.push(' ')
} else if is_last && !closer.is_empty() && line.is_empty() {
result.push('\n');
result.push_str(&indent_str);
} else {
result.push_str(&comment_line_separator);
if !has_leading_whitespace && result.ends_with(' ') {
result.pop();
}
}
}
if config.wrap_comments() && line.len() > fmt.shape.width && !has_url(line) {

133
src/lib.rs
View file

@ -44,6 +44,7 @@ use comment::{CharClasses, FullCodeCharKind};
use config::Config;
use filemap::FileMap;
use issues::{BadIssueSeeker, Issue};
use shape::Indent;
use utils::use_colored_tty;
use visitor::{FmtVisitor, SnippetProvider};
@ -529,6 +530,55 @@ fn parse_input(
}
}
/// Format the given snippet. The snippet is expected to be *complete* code.
/// When we cannot parse the given snippet, this function returns `None`.
pub fn format_snippet(snippet: &str, config: &Config) -> Option<String> {
let mut out: Vec<u8> = Vec::with_capacity(snippet.len() * 2);
let input = Input::Text(snippet.into());
let mut config = config.clone();
config.set().write_mode(config::WriteMode::Plain);
match format_input(input, &config, Some(&mut out)) {
// `format_input()` returns an empty string on parsing error.
Ok(..) if out.is_empty() && !snippet.is_empty() => None,
Ok(..) => String::from_utf8(out).ok(),
Err(..) => None,
}
}
/// Format the given code block. Mainly targeted for code block in comment.
/// The code block may be incomplete (i.e. parser may be unable to parse it).
/// To avoid panic in parser, we wrap the code block with a dummy function.
/// The returned code block does *not* end with newline.
pub fn format_code_block(code_snippet: &str, config: &Config) -> Option<String> {
// Wrap the given code block with `fn main()` if it does not have one.
let fn_main_prefix = "fn main() {\n";
let snippet = fn_main_prefix.to_owned() + code_snippet + "\n}";
// Trim "fn main() {" on the first line and "}" on the last line,
// then unindent the whole code block.
format_snippet(&snippet, config).map(|s| {
// 2 = "}\n"
s[fn_main_prefix.len()..s.len().checked_sub(2).unwrap_or(0)]
.lines()
.map(|line| {
if line.len() > config.tab_spaces() {
// Make sure that the line has leading whitespaces.
let indent_str =
Indent::from_width(config, config.tab_spaces()).to_string(config);
if line.starts_with(indent_str.as_ref()) {
&line[config.tab_spaces()..]
} else {
line
}
} else {
line
}
})
.collect::<Vec<_>>()
.join("\n")
})
}
pub fn format_input<T: Write>(
input: Input,
config: &Config,
@ -650,3 +700,86 @@ pub fn run(input: Input, config: &Config) -> Summary {
}
}
}
#[cfg(test)]
mod test {
use super::{format_code_block, format_snippet, Config};
#[test]
fn test_no_panic_on_format_snippet_and_format_code_block() {
// `format_snippet()` and `format_code_block()` should not panic
// even when we cannot parse the given snippet.
let snippet = "let";
assert!(format_snippet(snippet, &Config::default()).is_none());
assert!(format_code_block(snippet, &Config::default()).is_none());
}
fn test_format_inner<F>(formatter: F, input: &str, expected: &str) -> bool
where
F: Fn(&str, &Config) -> Option<String>,
{
let output = formatter(input, &Config::default());
output.is_some() && output.unwrap() == expected
}
#[test]
fn test_format_snippet() {
let snippet = "fn main() { println!(\"hello, world\"); }";
let expected = "fn main() {\n \
println!(\"hello, world\");\n\
}\n";
assert!(test_format_inner(format_snippet, snippet, expected));
}
#[test]
fn test_format_code_block() {
// simple code block
let code_block = "let x=3;";
let expected = "let x = 3;";
assert!(test_format_inner(format_code_block, code_block, expected));
// more complex code block, taken from chains.rs.
let code_block =
"let (nested_shape, extend) = if !parent_rewrite_contains_newline && is_continuable(&parent) {
(
chain_indent(context, shape.add_offset(parent_rewrite.len())),
context.config.indent_style() == IndentStyle::Visual || is_small_parent,
)
} else if is_block_expr(context, &parent, &parent_rewrite) {
match context.config.indent_style() {
// Try to put the first child on the same line with parent's last line
IndentStyle::Block => (parent_shape.block_indent(context.config.tab_spaces()), true),
// The parent is a block, so align the rest of the chain with the closing
// brace.
IndentStyle::Visual => (parent_shape, false),
}
} else {
(
chain_indent(context, shape.add_offset(parent_rewrite.len())),
false,
)
};
";
let expected =
"let (nested_shape, extend) = if !parent_rewrite_contains_newline && is_continuable(&parent) {
(
chain_indent(context, shape.add_offset(parent_rewrite.len())),
context.config.indent_style() == IndentStyle::Visual || is_small_parent,
)
} else if is_block_expr(context, &parent, &parent_rewrite) {
match context.config.indent_style() {
// Try to put the first child on the same line with parent's last line
IndentStyle::Block => (parent_shape.block_indent(context.config.tab_spaces()), true),
// The parent is a block, so align the rest of the chain with the closing
// brace.
IndentStyle::Visual => (parent_shape, false),
}
} else {
(
chain_indent(context, shape.add_offset(parent_rewrite.len())),
false,
)
};";
assert!(test_format_inner(format_code_block, code_block, expected));
}
}

10
tests/target/issue-2197.rs
View file

@ -4,8 +4,14 @@
/// ```rust
/// unsafe fn sum_sse2(x: i32x4) -> i32 {
/// let x = vendor::_mm_add_epi32(x, vendor::_mm_srli_si128(x.into(), 8).into());
/// let x = vendor::_mm_add_epi32(x, vendor::_mm_srli_si128(x.into(), 4).into());
/// let x = vendor::_mm_add_epi32(
/// x,
/// vendor::_mm_srli_si128(x.into(), 8).into(),
/// );
/// let x = vendor::_mm_add_epi32(
/// x,
/// vendor::_mm_srli_si128(x.into(), 4).into(),
/// );
/// vendor::_mm_cvtsi128_si32(x)
/// }
/// ```