// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license. use crate::colors; use dissimilar::diff as difference; use dissimilar::Chunk; use std::fmt::Write as _; /// Print diff of the same file_path, before and after formatting. /// /// Diff format is loosely based on GitHub diff formatting. pub fn diff(orig_text: &str, edit_text: &str) -> String { if orig_text == edit_text { return String::new(); } // normalize newlines as it adds too much noise if they differ let orig_text = orig_text.replace("\r\n", "\n"); let edit_text = edit_text.replace("\r\n", "\n"); if orig_text == edit_text { return " | Text differed by line endings.\n".to_string(); } DiffBuilder::build(&orig_text, &edit_text) } struct DiffBuilder { output: String, line_number_width: usize, orig_line: usize, edit_line: usize, orig: String, edit: String, has_changes: bool, } impl DiffBuilder { pub fn build(orig_text: &str, edit_text: &str) -> String { let mut diff_builder = DiffBuilder { output: String::new(), orig_line: 1, edit_line: 1, orig: String::new(), edit: String::new(), has_changes: false, line_number_width: { let line_count = std::cmp::max( orig_text.split('\n').count(), edit_text.split('\n').count(), ); line_count.to_string().chars().count() }, }; let chunks = difference(orig_text, edit_text); diff_builder.handle_chunks(chunks); diff_builder.output } fn handle_chunks<'a>(&'a mut self, chunks: Vec<Chunk<'a>>) { for chunk in chunks { match chunk { Chunk::Delete(s) => { let split = s.split('\n').enumerate(); for (i, s) in split { if i > 0 { self.orig.push('\n'); } self.orig.push_str(&fmt_rem_text_highlight(s)); } self.has_changes = true } Chunk::Insert(s) => { let split = s.split('\n').enumerate(); for (i, s) in split { if i > 0 { self.edit.push('\n'); } self.edit.push_str(&fmt_add_text_highlight(s)); } self.has_changes = true } Chunk::Equal(s) => { let split = s.split('\n').enumerate(); for (i, s) in split { if i > 0 { self.flush_changes(); } self.orig.push_str(&fmt_rem_text(s)); self.edit.push_str(&fmt_add_text(s)); } } } } self.flush_changes(); } fn flush_changes(&mut self) { if self.has_changes { self.write_line_diff(); self.orig_line += self.orig.split('\n').count(); self.edit_line += self.edit.split('\n').count(); self.has_changes = false; } else { self.orig_line += 1; self.edit_line += 1; } self.orig.clear(); self.edit.clear(); } fn write_line_diff(&mut self) { let split = self.orig.split('\n').enumerate(); for (i, s) in split { write!( self.output, "{:width$}{} ", self.orig_line + i, colors::gray(" |"), width = self.line_number_width ) .unwrap(); self.output.push_str(&fmt_rem()); self.output.push_str(s); self.output.push('\n'); } let split = self.edit.split('\n').enumerate(); for (i, s) in split { write!( self.output, "{:width$}{} ", self.edit_line + i, colors::gray(" |"), width = self.line_number_width ) .unwrap(); self.output.push_str(&fmt_add()); self.output.push_str(s); self.output.push('\n'); } } } fn fmt_add() -> String { colors::green_bold("+").to_string() } fn fmt_add_text(x: &str) -> String { colors::green(x).to_string() } fn fmt_add_text_highlight(x: &str) -> String { colors::black_on_green(x).to_string() } fn fmt_rem() -> String { colors::red_bold("-").to_string() } fn fmt_rem_text(x: &str) -> String { colors::red(x).to_string() } fn fmt_rem_text_highlight(x: &str) -> String { colors::white_on_red(x).to_string() } #[cfg(test)] mod tests { use super::*; #[test] fn test_diff() { run_test( "console.log('Hello World')", "console.log(\"Hello World\");", concat!( "1 | -console.log('Hello World')\n", "1 | +console.log(\"Hello World\");\n", ), ); run_test( "\n\n\n\nconsole.log(\n'Hello World'\n)", "console.log(\n\"Hello World\"\n);", concat!( "1 | -\n", "2 | -\n", "3 | -\n", "4 | -\n", "5 | -console.log(\n", "1 | +console.log(\n", "6 | -'Hello World'\n", "2 | +\"Hello World\"\n", "7 | -)\n3 | +);\n", ), ); } #[test] fn test_eof_newline_missing() { run_test( "test\nsome line text test", "test\nsome line text test\n", concat!( "2 | -some line text test\n", "2 | +some line text test\n", "3 | +\n", ), ); } #[test] fn test_newlines_differing() { run_test("test\n", "test\r\n", " | Text differed by line endings.\n"); } fn run_test(diff_text1: &str, diff_text2: &str, expected_output: &str) { assert_eq!( test_util::strip_ansi_codes(&diff(diff_text1, diff_text2,)), expected_output, ); } }