Add context and normal diff modes

This commit is contained in:
Michael Howell
2021-03-09 16:23:46 -07:00
parent 2e84164d2f
commit e72ea046b7
15 changed files with 1526 additions and 36 deletions
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[package]
name = "normal-diff"
version = "0.1.0"
authors = [
"Michael Howell <michael@notriddle.com>",
"The Rust Project Developers"
]
edition = "2018"
description = "An implementation of the GNU unified diff format"
license = "MIT OR Apache-2.0"
repository = "https://github.com/notriddle/diffutils"
exclude = [ "fuzz" ]
[dependencies]
diff = "0.1.10"
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use std::io::Write;
#[derive(Debug, PartialEq)]
struct Mismatch {
pub line_number_expected: usize,
pub line_number_actual: usize,
pub expected: Vec<Vec<u8>>,
pub actual: Vec<Vec<u8>>,
}
impl Mismatch {
fn new(line_number_expected: usize, line_number_actual: usize) -> Mismatch {
Mismatch {
line_number_expected,
line_number_actual,
expected: Vec::new(),
actual: Vec::new(),
}
}
}
// Produces a diff between the expected output and actual output.
fn make_diff(expected: &[u8], actual: &[u8]) -> Vec<Mismatch> {
let mut line_number_expected = 1;
let mut line_number_actual = 1;
let mut results = Vec::new();
let mut mismatch = Mismatch::new(line_number_expected, line_number_actual);
let mut expected_lines: Vec<&[u8]> = expected.split(|&c| c == b'\n').collect();
let mut actual_lines: Vec<&[u8]> = actual.split(|&c| c == b'\n').collect();
debug_assert_eq!(b"".split(|&c| c == b'\n').count(), 1);
// ^ means that underflow here is impossible
let _expected_lines_count = expected_lines.len() - 1;
let _actual_lines_count = actual_lines.len() - 1;
if expected_lines.last() == Some(&&b""[..]) {
expected_lines.pop();
}
if actual_lines.last() == Some(&&b""[..]) {
actual_lines.pop();
}
for result in diff::slice(&expected_lines, &actual_lines) {
match result {
diff::Result::Left(str) => {
if mismatch.actual.len() != 0 {
results.push(mismatch);
mismatch = Mismatch::new(line_number_expected, line_number_actual);
}
mismatch.expected.push(str.to_vec());
line_number_expected += 1;
}
diff::Result::Right(str) => {
mismatch.actual.push(str.to_vec());
line_number_actual += 1;
}
diff::Result::Both(_str, _) => {
line_number_expected += 1;
line_number_actual += 1;
if mismatch.actual.len() != 0 || mismatch.expected.len() != 0 {
results.push(mismatch);
mismatch = Mismatch::new(line_number_expected, line_number_actual);
} else {
mismatch.line_number_expected = line_number_expected;
mismatch.line_number_actual = line_number_actual;
}
}
}
}
if mismatch.actual.len() != 0 || mismatch.expected.len() != 0 {
results.push(mismatch);
}
results
}
pub fn diff(expected: &[u8], actual: &[u8]) -> Vec<u8> {
let mut output = Vec::new();
let diff_results = make_diff(expected, actual);
for result in diff_results {
let line_number_expected = result.line_number_expected;
let line_number_actual = result.line_number_actual;
let expected_count = result.expected.len();
let actual_count = result.actual.len();
match (expected_count, actual_count) {
(0, 0) => unreachable!(),
(0, _) => writeln!(
&mut output,
"{}a{},{}",
line_number_expected - 1,
line_number_actual,
line_number_actual + actual_count - 1
)
.unwrap(),
(_, 0) => writeln!(
&mut output,
"{},{}d{}",
line_number_expected,
expected_count + line_number_expected - 1,
line_number_actual - 1
)
.unwrap(),
_ => writeln!(
&mut output,
"{},{}c{},{}",
line_number_expected,
expected_count + line_number_expected - 1,
line_number_actual,
actual_count + line_number_actual - 1
)
.unwrap(),
}
for expected in &result.expected {
write!(&mut output, "< ").unwrap();
output.write_all(expected).unwrap();
writeln!(&mut output, "").unwrap();
}
if expected_count != 0 && actual_count != 0 {
writeln!(&mut output, "---").unwrap();
}
for actual in &result.actual {
write!(&mut output, "> ").unwrap();
output.write_all(actual).unwrap();
writeln!(&mut output, "").unwrap();
}
}
output
}
#[test]
fn test_permutations() {
// test all possible six-line files.
let _ = std::fs::create_dir("target");
for &a in &[0, 1, 2] {
for &b in &[0, 1, 2] {
for &c in &[0, 1, 2] {
for &d in &[0, 1, 2] {
for &e in &[0, 1, 2] {
for &f in &[0, 1, 2] {
use std::fs::{self, File};
use std::io::Write;
use std::process::Command;
let mut alef = Vec::new();
let mut bet = Vec::new();
alef.write_all(if a == 0 { b"a\n" } else { b"b\n" })
.unwrap();
if a != 2 {
bet.write_all(b"b\n").unwrap();
}
alef.write_all(if b == 0 { b"c\n" } else { b"d\n" })
.unwrap();
if b != 2 {
bet.write_all(b"d\n").unwrap();
}
alef.write_all(if c == 0 { b"e\n" } else { b"f\n" })
.unwrap();
if c != 2 {
bet.write_all(b"f\n").unwrap();
}
alef.write_all(if d == 0 { b"g\n" } else { b"h\n" })
.unwrap();
if d != 2 {
bet.write_all(b"h\n").unwrap();
}
alef.write_all(if e == 0 { b"i\n" } else { b"j\n" })
.unwrap();
if e != 2 {
bet.write_all(b"j\n").unwrap();
}
alef.write_all(if f == 0 { b"k\n" } else { b"l\n" })
.unwrap();
if f != 2 {
bet.write_all(b"l\n").unwrap();
}
// This test diff is intentionally reversed.
// We want it to turn the alef into bet.
let diff = diff(&alef, &bet);
File::create("target/ab.diff")
.unwrap()
.write_all(&diff)
.unwrap();
let mut fa = File::create("target/alef").unwrap();
fa.write_all(&alef[..]).unwrap();
let mut fb = File::create("target/bet").unwrap();
fb.write_all(&bet[..]).unwrap();
let _ = fa;
let _ = fb;
let output = Command::new("patch")
.arg("-p0")
.arg("target/alef")
.stdin(File::open("target/ab.diff").unwrap())
.output()
.unwrap();
if !output.status.success() {
panic!("{:?}", output);
}
//println!("{}", String::from_utf8_lossy(&output.stdout));
//println!("{}", String::from_utf8_lossy(&output.stderr));
let alef = fs::read("target/alef").unwrap();
assert_eq!(alef, bet);
}
}
}
}
}
}
}
#[test]
fn test_permutations_empty_lines() {
// test all possible six-line files with missing newlines.
let _ = std::fs::create_dir("target");
for &a in &[0, 1, 2] {
for &b in &[0, 1, 2] {
for &c in &[0, 1, 2] {
for &d in &[0, 1, 2] {
for &e in &[0, 1, 2] {
for &f in &[0, 1, 2] {
use std::fs::{self, File};
use std::io::Write;
use std::process::Command;
let mut alef = Vec::new();
let mut bet = Vec::new();
alef.write_all(if a == 0 { b"\n" } else { b"b\n" }).unwrap();
if a != 2 {
bet.write_all(b"b\n").unwrap();
}
alef.write_all(if b == 0 { b"\n" } else { b"d\n" }).unwrap();
if b != 2 {
bet.write_all(b"d\n").unwrap();
}
alef.write_all(if c == 0 { b"\n" } else { b"f\n" }).unwrap();
if c != 2 {
bet.write_all(b"f\n").unwrap();
}
alef.write_all(if d == 0 { b"\n" } else { b"h\n" }).unwrap();
if d != 2 {
bet.write_all(b"h\n").unwrap();
}
alef.write_all(if e == 0 { b"\n" } else { b"j\n" }).unwrap();
if e != 2 {
bet.write_all(b"j\n").unwrap();
}
alef.write_all(if f == 0 { b"\n" } else { b"l\n" }).unwrap();
if f != 2 {
bet.write_all(b"l\n").unwrap();
}
// This test diff is intentionally reversed.
// We want it to turn the alef into bet.
let diff = diff(&alef, &bet);
File::create("target/ab_.diff")
.unwrap()
.write_all(&diff)
.unwrap();
let mut fa = File::create("target/alef_").unwrap();
fa.write_all(&alef[..]).unwrap();
let mut fb = File::create("target/bet_").unwrap();
fb.write_all(&bet[..]).unwrap();
let _ = fa;
let _ = fb;
let output = Command::new("patch")
.arg("-p0")
.arg("target/alef_")
.stdin(File::open("target/ab_.diff").unwrap())
.output()
.unwrap();
if !output.status.success() {
panic!("{:?}", output);
}
//println!("{}", String::from_utf8_lossy(&output.stdout));
//println!("{}", String::from_utf8_lossy(&output.stderr));
let alef = fs::read("target/alef_").unwrap();
assert_eq!(alef, bet);
}
}
}
}
}
}
}
#[test]
fn test_permutations_reverse() {
// test all possible six-line files.
let _ = std::fs::create_dir("target");
for &a in &[0, 1, 2] {
for &b in &[0, 1, 2] {
for &c in &[0, 1, 2] {
for &d in &[0, 1, 2] {
for &e in &[0, 1, 2] {
for &f in &[0, 1, 2] {
use std::fs::{self, File};
use std::io::Write;
use std::process::Command;
let mut alef = Vec::new();
let mut bet = Vec::new();
alef.write_all(if a == 0 { b"a\n" } else { b"f\n" })
.unwrap();
if a != 2 {
bet.write_all(b"a\n").unwrap();
}
alef.write_all(if b == 0 { b"b\n" } else { b"e\n" })
.unwrap();
if b != 2 {
bet.write_all(b"b\n").unwrap();
}
alef.write_all(if c == 0 { b"c\n" } else { b"d\n" })
.unwrap();
if c != 2 {
bet.write_all(b"c\n").unwrap();
}
alef.write_all(if d == 0 { b"d\n" } else { b"c\n" })
.unwrap();
if d != 2 {
bet.write_all(b"d\n").unwrap();
}
alef.write_all(if e == 0 { b"e\n" } else { b"b\n" })
.unwrap();
if e != 2 {
bet.write_all(b"e\n").unwrap();
}
alef.write_all(if f == 0 { b"f\n" } else { b"a\n" })
.unwrap();
if f != 2 {
bet.write_all(b"f\n").unwrap();
}
// This test diff is intentionally reversed.
// We want it to turn the alef into bet.
let diff = diff(&alef, &bet);
File::create("target/abr.diff")
.unwrap()
.write_all(&diff)
.unwrap();
let mut fa = File::create("target/alefr").unwrap();
fa.write_all(&alef[..]).unwrap();
let mut fb = File::create("target/betr").unwrap();
fb.write_all(&bet[..]).unwrap();
let _ = fa;
let _ = fb;
let output = Command::new("patch")
.arg("-p0")
.arg("target/alefr")
.stdin(File::open("target/abr.diff").unwrap())
.output()
.unwrap();
if !output.status.success() {
panic!("{:?}", output);
}
//println!("{}", String::from_utf8_lossy(&output.stdout));
//println!("{}", String::from_utf8_lossy(&output.stderr));
let alef = fs::read("target/alefr").unwrap();
assert_eq!(alef, bet);
}
}
}
}
}
}
}