Add lib.rs so difftastic can be used as a library (& serde)

Cargo.toml

@@ -41,6 +41,7 @@ const_format = "0.2.22"
 owo-colors = "3.2.0"
 rpds = "0.10.0"
 wu-diff = "0.1.2"
+serde = { version = "1.0", features = ["derive"] }
 
 [dev-dependencies]
 pretty_assertions = "1.0.0"

src/guess_language.rs

@@ -50,7 +50,7 @@ pub enum Language {
     Zig,
 }
 
-use Language::*;
+pub use Language::*;
 
 pub fn guess(path: &Path, src: &str) -> Option<Language> {
     if let Some(lang) = from_emacs_mode_header(src) {

src/lib.rs

@@ -0,0 +1,323 @@
+//! Difftastic is a syntactic diff tool.
+//!
+//! For usage instructions and advice on contributing, see [the
+//! manual](http://difftastic.wilfred.me.uk/).
+//!
+
+// This tends to trigger on larger tuples of simple types, and naming
+// them would probably be worse for readability.
+#![allow(clippy::type_complexity)]
+// == "" is often clearer when dealing with strings.
+#![allow(clippy::comparison_to_empty)]
+// It's common to have pairs foo_lhs and foo_rhs, leading to double
+// the number of arguments and triggering this lint.
+#![allow(clippy::too_many_arguments)]
+
+mod context;
+mod dijkstra;
+pub mod files;
+mod graph;
+pub mod guess_language;
+mod hunks;
+mod inline;
+mod line_parser;
+mod lines;
+mod myers_diff;
+pub mod option_types;
+mod positions;
+mod side_by_side;
+mod sliders;
+pub mod style;
+pub mod summary;
+pub mod syntax;
+pub mod tree_sitter_parser;
+mod unchanged;
+
+#[macro_use]
+extern crate log;
+
+use crate::hunks::{matched_pos_to_hunks, merge_adjacent};
+use context::opposite_positions;
+use guess_language::guess;
+use log::info;
+use mimalloc::MiMalloc;
+use option_types::DisplayMode;
+
+/// The global allocator used by difftastic.
+///
+/// Diffing allocates a large amount of memory, and `MiMalloc` performs
+/// better.
+#[global_allocator]
+static GLOBAL: MiMalloc = MiMalloc;
+
+use sliders::fix_all_sliders;
+use std::{env, path::Path};
+use style::BackgroundColor;
+pub use summary::{DiffResult, FileContent};
+use syntax::{init_next_prev, Syntax};
+use typed_arena::Arena;
+
+use crate::{
+    dijkstra::mark_syntax, files::is_probably_binary, lines::MaxLine, syntax::init_all_info,
+    tree_sitter_parser as tsp,
+};
+
+extern crate pretty_env_logger;
+
+pub fn diff_file_content(
+    display_path: &str,
+    lhs_bytes: &[u8],
+    rhs_bytes: &[u8],
+    node_limit: u32,
+    byte_limit: usize,
+    language_override: Option<guess_language::Language>,
+) -> DiffResult {
+    if is_probably_binary(lhs_bytes) || is_probably_binary(rhs_bytes) {
+        return DiffResult {
+            path: display_path.into(),
+            language: None,
+            lhs_src: FileContent::Binary(lhs_bytes.to_vec()),
+            rhs_src: FileContent::Binary(rhs_bytes.to_vec()),
+            lhs_positions: vec![],
+            rhs_positions: vec![],
+        };
+    }
+
+    // TODO: don't replace tab characters inside string literals.
+    let mut lhs_src = String::from_utf8_lossy(lhs_bytes)
+        .to_string()
+        .replace('\t', "    ");
+    let mut rhs_src = String::from_utf8_lossy(rhs_bytes)
+        .to_string()
+        .replace('\t', "    ");
+
+    // Ignore the trailing newline, if present.
+    // TODO: highlight if this has changes (#144).
+    // TODO: factor out a string cleaning function.
+    if lhs_src.ends_with('\n') {
+        lhs_src.pop();
+    }
+    if rhs_src.ends_with('\n') {
+        rhs_src.pop();
+    }
+
+    // TODO: take a Path directly instead.
+    let path = Path::new(&display_path);
+
+    // Take the larger of the two files when guessing the
+    // language. This is useful when we've added or removed a whole
+    // file.
+    let guess_src = if lhs_src.len() > rhs_src.len() {
+        &lhs_src
+    } else {
+        &rhs_src
+    };
+    let ts_lang = language_override
+        .or_else(|| guess(path, guess_src))
+        .map(tsp::from_language);
+
+    if lhs_bytes == rhs_bytes {
+        // If the two files are completely identical, return early
+        // rather than doing any more work.
+        return DiffResult {
+            path: display_path.into(),
+            language: ts_lang.map(|l| l.name.into()),
+            lhs_src: FileContent::Text("".into()),
+            rhs_src: FileContent::Text("".into()),
+            lhs_positions: vec![],
+            rhs_positions: vec![],
+        };
+    }
+
+    let (lang_name, lhs_positions, rhs_positions) = match ts_lang {
+        _ if lhs_bytes.len() > byte_limit || rhs_bytes.len() > byte_limit => {
+            let lhs_positions = line_parser::change_positions(&lhs_src, &rhs_src);
+            let rhs_positions = line_parser::change_positions(&rhs_src, &lhs_src);
+            (
+                Some("Text (exceeded DFT_BYTE_LIMIT)".into()),
+                lhs_positions,
+                rhs_positions,
+            )
+        }
+        Some(ts_lang) => {
+            let arena = Arena::new();
+            let lhs = tsp::parse(&arena, &lhs_src, &ts_lang);
+            let rhs = tsp::parse(&arena, &rhs_src, &ts_lang);
+
+            init_all_info(&lhs, &rhs);
+
+            let possibly_changed = if env::var("DFT_DBG_KEEP_UNCHANGED").is_ok() {
+                vec![(lhs.clone(), rhs.clone())]
+            } else {
+                unchanged::mark_unchanged(&lhs, &rhs)
+            };
+
+            let possibly_changed_max = max_num_nodes(&possibly_changed);
+            if possibly_changed_max > node_limit {
+                info!(
+                    "Found {} nodes, exceeding the limit {}",
+                    possibly_changed_max, node_limit
+                );
+
+                let lhs_positions = line_parser::change_positions(&lhs_src, &rhs_src);
+                let rhs_positions = line_parser::change_positions(&rhs_src, &lhs_src);
+                (
+                    Some("Text (exceeded DFT_NODE_LIMIT)".into()),
+                    lhs_positions,
+                    rhs_positions,
+                )
+            } else {
+                for (lhs_section_nodes, rhs_section_nodes) in possibly_changed {
+                    init_next_prev(&lhs_section_nodes);
+                    init_next_prev(&rhs_section_nodes);
+
+                    mark_syntax(
+                        lhs_section_nodes.get(0).copied(),
+                        rhs_section_nodes.get(0).copied(),
+                    );
+
+                    fix_all_sliders(&lhs_section_nodes);
+                    fix_all_sliders(&rhs_section_nodes);
+                }
+
+                let lhs_positions = syntax::change_positions(&lhs);
+                let rhs_positions = syntax::change_positions(&rhs);
+                (Some(ts_lang.name.into()), lhs_positions, rhs_positions)
+            }
+        }
+        None => {
+            let lhs_positions = line_parser::change_positions(&lhs_src, &rhs_src);
+            let rhs_positions = line_parser::change_positions(&rhs_src, &lhs_src);
+            (None, lhs_positions, rhs_positions)
+        }
+    };
+
+    DiffResult {
+        path: display_path.into(),
+        language: lang_name,
+        lhs_src: FileContent::Text(lhs_src),
+        rhs_src: FileContent::Text(rhs_src),
+        lhs_positions,
+        rhs_positions,
+    }
+}
+
+// TODO: factor out a DiffOptions struct.
+pub fn print_diff_result(
+    display_width: usize,
+    use_color: bool,
+    display_mode: DisplayMode,
+    background: BackgroundColor,
+    print_unchanged: bool,
+    summary: &DiffResult,
+) {
+    match (&summary.lhs_src, &summary.rhs_src) {
+        (FileContent::Text(lhs_src), FileContent::Text(rhs_src)) => {
+            let opposite_to_lhs = opposite_positions(&summary.lhs_positions);
+            let opposite_to_rhs = opposite_positions(&summary.rhs_positions);
+
+            let hunks = matched_pos_to_hunks(&summary.lhs_positions, &summary.rhs_positions);
+            let hunks = merge_adjacent(
+                &hunks,
+                &opposite_to_lhs,
+                &opposite_to_rhs,
+                lhs_src.max_line(),
+                rhs_src.max_line(),
+            );
+
+            let lang_name = summary.language.clone().unwrap_or_else(|| "Text".into());
+            if hunks.is_empty() {
+                if print_unchanged {
+                    println!(
+                        "{}",
+                        style::header(&summary.path, 1, 1, &lang_name, use_color, background)
+                    );
+                    if lang_name == "Text" || summary.lhs_src == summary.rhs_src {
+                        // TODO: there are other Text names now, so
+                        // they will hit the second case incorrectly.
+                        println!("No changes.\n");
+                    } else {
+                        println!("No syntactic changes.\n");
+                    }
+                }
+                return;
+            }
+
+            match display_mode {
+                DisplayMode::Inline => {
+                    inline::print(
+                        lhs_src,
+                        rhs_src,
+                        &summary.lhs_positions,
+                        &summary.rhs_positions,
+                        &hunks,
+                        &summary.path,
+                        &lang_name,
+                        use_color,
+                        background,
+                    );
+                }
+                DisplayMode::SideBySide | DisplayMode::SideBySideShowBoth => {
+                    side_by_side::print(
+                        &hunks,
+                        display_width,
+                        use_color,
+                        display_mode,
+                        background,
+                        &summary.path,
+                        &lang_name,
+                        lhs_src,
+                        rhs_src,
+                        &summary.lhs_positions,
+                        &summary.rhs_positions,
+                    );
+                }
+            }
+        }
+        (FileContent::Binary(lhs_bytes), FileContent::Binary(rhs_bytes)) => {
+            let changed = lhs_bytes != rhs_bytes;
+            if print_unchanged || changed {
+                println!(
+                    "{}",
+                    style::header(&summary.path, 1, 1, "binary", use_color, background)
+                );
+                if changed {
+                    println!("Binary contents changed.");
+                } else {
+                    println!("No changes.");
+                }
+            }
+        }
+        (_, FileContent::Binary(_)) | (FileContent::Binary(_), _) => {
+            // We're diffing a binary file against a text file.
+            println!(
+                "{}",
+                style::header(&summary.path, 1, 1, "binary", use_color, background)
+            );
+            println!("Binary contents changed.");
+        }
+    }
+}
+
+/// What is the total number of nodes in `roots`?
+fn num_nodes(roots: &[&Syntax]) -> u32 {
+    roots
+        .iter()
+        .map(|n| {
+            1 + match n {
+                Syntax::List {
+                    num_descendants, ..
+                } => *num_descendants,
+                Syntax::Atom { .. } => 0,
+            }
+        })
+        .sum()
+}
+
+fn max_num_nodes(roots_vec: &[(Vec<&Syntax>, Vec<&Syntax>)]) -> u32 {
+    roots_vec
+        .iter()
+        .map(|(lhs, rhs)| num_nodes(lhs) + num_nodes(rhs))
+        .max()
+        .unwrap_or(0)
+}

src/lines.rs

@@ -1,6 +1,7 @@
 //! Manipulate lines of text and groups of lines.
 
 use crate::positions::SingleLineSpan;
+use serde::{Deserialize, Serialize};
 use std::{
     cmp::{max, Ordering},
     fmt,
@@ -10,7 +11,7 @@ use std::{
 /// other numerical data.
 ///
 /// Zero-indexed internally.
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Serialize, Deserialize, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct LineNumber(pub usize);
 
 impl LineNumber {