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Implement -q/--brief option (fixes #19) (#20)
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* Implement -q/--brief option

* Optimization: stop analyzing the files as soon as there are any differences

* Unit tests for the stop_early parameter

* Simplify checks
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@oSoMoN
oSoMoN authored Mar 19, 2024
1 parent 62e10c6 commit 4ed7ea1
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Showing 7 changed files with 394 additions and 40 deletions.
124 changes: 113 additions & 11 deletions src/context_diff.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,12 @@ impl Mismatch {
}

// Produces a diff between the expected output and actual output.
fn make_diff(expected: &[u8], actual: &[u8], context_size: usize) -> Vec<Mismatch> {
fn make_diff(
expected: &[u8],
actual: &[u8],
context_size: usize,
stop_early: bool,
) -> Vec<Mismatch> {
let mut line_number_expected = 1;
let mut line_number_actual = 1;
let mut context_queue: VecDeque<&[u8]> = VecDeque::with_capacity(context_size);
Expand Down Expand Up @@ -191,6 +196,10 @@ fn make_diff(expected: &[u8], actual: &[u8], context_size: usize) -> Vec<Mismatc
line_number_actual += 1;
}
}
if stop_early && !results.is_empty() {
// Optimization: stop analyzing the files as soon as there are any differences
return results;
}
}

results.push(mismatch);
Expand Down Expand Up @@ -260,12 +269,16 @@ pub fn diff(
actual: &[u8],
actual_filename: &str,
context_size: usize,
stop_early: bool,
) -> Vec<u8> {
let mut output = format!("*** {expected_filename}\t\n--- {actual_filename}\t\n").into_bytes();
let diff_results = make_diff(expected, actual, context_size);
let diff_results = make_diff(expected, actual, context_size, stop_early);
if diff_results.is_empty() {
return Vec::new();
};
}
if stop_early {
return output;
}
for result in diff_results {
let mut line_number_expected = result.line_number_expected;
let mut line_number_actual = result.line_number_actual;
Expand Down Expand Up @@ -404,8 +417,14 @@ mod tests {
}
// This test diff is intentionally reversed.
// We want it to turn the alef into bet.
let diff =
diff(&alef, "a/alef", &bet, &format!("{target}/alef"), 2);
let diff = diff(
&alef,
"a/alef",
&bet,
&format!("{target}/alef"),
2,
false,
);
File::create(&format!("{target}/ab.diff"))
.unwrap()
.write_all(&diff)
Expand Down Expand Up @@ -477,8 +496,14 @@ mod tests {
}
// This test diff is intentionally reversed.
// We want it to turn the alef into bet.
let diff =
diff(&alef, "a/alef_", &bet, &format!("{target}/alef_"), 2);
let diff = diff(
&alef,
"a/alef_",
&bet,
&format!("{target}/alef_"),
2,
false,
);
File::create(&format!("{target}/ab_.diff"))
.unwrap()
.write_all(&diff)
Expand Down Expand Up @@ -553,8 +578,14 @@ mod tests {
};
// This test diff is intentionally reversed.
// We want it to turn the alef into bet.
let diff =
diff(&alef, "a/alefx", &bet, &format!("{target}/alefx"), 2);
let diff = diff(
&alef,
"a/alefx",
&bet,
&format!("{target}/alefx"),
2,
false,
);
File::create(&format!("{target}/abx.diff"))
.unwrap()
.write_all(&diff)
Expand Down Expand Up @@ -632,8 +663,14 @@ mod tests {
}
// This test diff is intentionally reversed.
// We want it to turn the alef into bet.
let diff =
diff(&alef, "a/alefr", &bet, &format!("{target}/alefr"), 2);
let diff = diff(
&alef,
"a/alefr",
&bet,
&format!("{target}/alefr"),
2,
false,
);
File::create(&format!("{target}/abr.diff"))
.unwrap()
.write_all(&diff)
Expand Down Expand Up @@ -662,4 +699,69 @@ mod tests {
}
}
}

#[test]
fn test_stop_early() {
let from_filename = "foo";
let from = vec!["a", "b", "c", ""].join("\n");
let to_filename = "bar";
let to = vec!["a", "d", "c", ""].join("\n");
let context_size: usize = 3;

let diff_full = diff(
from.as_bytes(),
from_filename,
to.as_bytes(),
to_filename,
context_size,
false,
);
let expected_full = vec![
"*** foo\t",
"--- bar\t",
"***************",
"*** 1,3 ****",
" a",
"! b",
" c",
"--- 1,3 ----",
" a",
"! d",
" c",
"",
]
.join("\n");
assert_eq!(diff_full, expected_full.as_bytes());

let diff_brief = diff(
from.as_bytes(),
from_filename,
to.as_bytes(),
to_filename,
context_size,
true,
);
let expected_brief = vec!["*** foo\t", "--- bar\t", ""].join("\n");
assert_eq!(diff_brief, expected_brief.as_bytes());

let nodiff_full = diff(
from.as_bytes(),
from_filename,
from.as_bytes(),
to_filename,
context_size,
false,
);
assert!(nodiff_full.is_empty());

let nodiff_brief = diff(
from.as_bytes(),
from_filename,
from.as_bytes(),
to_filename,
context_size,
true,
);
assert!(nodiff_brief.is_empty());
}
}
38 changes: 33 additions & 5 deletions src/ed_diff.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -42,7 +42,7 @@ impl Mismatch {
}

// Produces a diff between the expected output and actual output.
fn make_diff(expected: &[u8], actual: &[u8]) -> Result<Vec<Mismatch>, DiffError> {
fn make_diff(expected: &[u8], actual: &[u8], stop_early: bool) -> Result<Vec<Mismatch>, DiffError> {
let mut line_number_expected = 1;
let mut line_number_actual = 1;
let mut results = Vec::new();
Expand Down Expand Up @@ -94,6 +94,10 @@ fn make_diff(expected: &[u8], actual: &[u8]) -> Result<Vec<Mismatch>, DiffError>
}
}
}
if stop_early && !results.is_empty() {
// Optimization: stop analyzing the files as soon as there are any differences
return Ok(results);
}
}

if !mismatch.actual.is_empty() || !mismatch.expected.is_empty() {
Expand All @@ -103,9 +107,13 @@ fn make_diff(expected: &[u8], actual: &[u8]) -> Result<Vec<Mismatch>, DiffError>
Ok(results)
}

pub fn diff(expected: &[u8], actual: &[u8]) -> Result<Vec<u8>, DiffError> {
pub fn diff(expected: &[u8], actual: &[u8], stop_early: bool) -> Result<Vec<u8>, DiffError> {
let mut output = Vec::new();
let diff_results = make_diff(expected, actual)?;
let diff_results = make_diff(expected, actual, stop_early)?;
if stop_early && !diff_results.is_empty() {
write!(&mut output, "\0").unwrap();
return Ok(output);
}
let mut lines_offset = 0;
for result in diff_results {
let line_number_expected: isize = result.line_number_expected as isize + lines_offset;
Expand Down Expand Up @@ -152,7 +160,7 @@ mod tests {
use super::*;
use pretty_assertions::assert_eq;
pub fn diff_w(expected: &[u8], actual: &[u8], filename: &str) -> Result<Vec<u8>, DiffError> {
let mut output = diff(expected, actual)?;
let mut output = diff(expected, actual, false)?;
writeln!(&mut output, "w {filename}").unwrap();
Ok(output)
}
Expand All @@ -161,7 +169,7 @@ mod tests {
fn test_basic() {
let from = b"a\n";
let to = b"b\n";
let diff = diff(from, to).unwrap();
let diff = diff(from, to, false).unwrap();
let expected = vec!["1c", "b", ".", ""].join("\n");
assert_eq!(diff, expected.as_bytes());
}
Expand Down Expand Up @@ -390,4 +398,24 @@ mod tests {
}
}
}

#[test]
fn test_stop_early() {
let from = vec!["a", "b", "c", ""].join("\n");
let to = vec!["a", "d", "c", ""].join("\n");

let diff_full = diff(from.as_bytes(), to.as_bytes(), false).unwrap();
let expected_full = vec!["2c", "d", ".", ""].join("\n");
assert_eq!(diff_full, expected_full.as_bytes());

let diff_brief = diff(from.as_bytes(), to.as_bytes(), true).unwrap();
let expected_brief = "\0".as_bytes();
assert_eq!(diff_brief, expected_brief);

let nodiff_full = diff(from.as_bytes(), from.as_bytes(), false).unwrap();
assert!(nodiff_full.is_empty());

let nodiff_brief = diff(from.as_bytes(), from.as_bytes(), true).unwrap();
assert!(nodiff_brief.is_empty());
}
}
17 changes: 14 additions & 3 deletions src/main.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@ fn main() -> ExitCode {
context_count,
format,
report_identical_files,
brief,
} = parse_params(opts).unwrap_or_else(|error| {
eprintln!("{error}");
exit(2);
Expand Down Expand Up @@ -64,27 +65,37 @@ fn main() -> ExitCode {
};
// run diff
let result: Vec<u8> = match format {
Format::Normal => normal_diff::diff(&from_content, &to_content),
Format::Normal => normal_diff::diff(&from_content, &to_content, brief),
Format::Unified => unified_diff::diff(
&from_content,
&from.to_string_lossy(),
&to_content,
&to.to_string_lossy(),
context_count,
brief,
),
Format::Context => context_diff::diff(
&from_content,
&from.to_string_lossy(),
&to_content,
&to.to_string_lossy(),
context_count,
brief,
),
Format::Ed => ed_diff::diff(&from_content, &to_content).unwrap_or_else(|error| {
Format::Ed => ed_diff::diff(&from_content, &to_content, brief).unwrap_or_else(|error| {
eprintln!("{error}");
exit(2);
}),
};
io::stdout().write_all(&result).unwrap();
if brief && !result.is_empty() {
println!(
"Files {} and {} differ",
from.to_string_lossy(),
to.to_string_lossy()
);
} else {
io::stdout().write_all(&result).unwrap();
}
if result.is_empty() {
maybe_report_identical_files();
ExitCode::SUCCESS
Expand Down
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