feat: word wrapping in code previewer (#1159)

Co-authored-by: Lex Moskovski <alex@moskovski.com>
Co-authored-by: sxyazi <sxyazi@gmail.com>

yazi-config/preset/yazi.toml

@@ -17,6 +17,7 @@ mouse_events   = [ "click", "scroll" ]
 title_format   = "Yazi: {cwd}"
 
 [preview]
+wrap            = "no"
 tab_size        = 2
 max_width       = 600
 max_height      = 900

yazi-config/src/preview/mod.rs

@@ -1,3 +1,5 @@
 mod preview;
+mod wrap;
 
 pub use preview::*;
+pub use wrap::*;

yazi-config/src/preview/preview.rs

@@ -5,10 +5,15 @@ use serde::{Deserialize, Serialize};
 use validator::Validate;
 use yazi_shared::fs::expand_path;
 
+use super::PreviewWrap;
 use crate::Xdg;
 
+#[rustfmt::skip]
+const TABS: &[&str] = &["", " ", "  ", "   ", "    ", "     ", "      ", "       ", "        ", "         ", "          ", "           ", "            ", "             ", "              ", "               ", "                "];
+
 #[derive(Debug, Serialize)]
 pub struct Preview {
+	pub wrap:       PreviewWrap,
 	pub tab_size:   u8,
 	pub max_width:  u32,
 	pub max_height: u32,
@@ -32,19 +37,11 @@ impl Preview {
 	}
 
 	#[inline]
-	pub fn indent(&self) -> Cow<'static, str> {
-		match self.tab_size {
-			0 => Cow::Borrowed(""),
-			1 => Cow::Borrowed(" "),
-			2 => Cow::Borrowed("  "),
-			3 => Cow::Borrowed("   "),
-			4 => Cow::Borrowed("    "),
-			5 => Cow::Borrowed("     "),
-			6 => Cow::Borrowed("      "),
-			7 => Cow::Borrowed("       "),
-			8 => Cow::Borrowed("        "),
-			n => Cow::Owned(" ".repeat(n as usize)),
-		}
+	pub fn indent(&self) -> Cow<'static, str> { Self::indent_with(self.tab_size as usize) }
+
+	#[inline]
+	pub fn indent_with(n: usize) -> Cow<'static, str> {
+		if let Some(s) = TABS.get(n) { Cow::Borrowed(s) } else { Cow::Owned(" ".repeat(n)) }
 	}
 }
 
@@ -58,6 +55,7 @@ impl FromStr for Preview {
 		}
 		#[derive(Deserialize, Validate)]
 		struct Shadow {
+			wrap:       PreviewWrap,
 			tab_size:   u8,
 			max_width:  u32,
 			max_height: u32,
@@ -84,6 +82,7 @@ impl FromStr for Preview {
 		std::fs::create_dir_all(&cache_dir).context("Failed to create cache directory")?;
 
 		Ok(Preview {
+			wrap: preview.wrap,
 			tab_size: preview.tab_size,
 			max_width: preview.max_width,
 			max_height: preview.max_height,

yazi-config/src/preview/wrap.rs

@@ -0,0 +1,29 @@
+use std::str::FromStr;
+
+use anyhow::bail;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Copy, Debug, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(try_from = "String")]
+pub enum PreviewWrap {
+	No,
+	Yes,
+}
+
+impl FromStr for PreviewWrap {
+	type Err = anyhow::Error;
+
+	fn from_str(s: &str) -> Result<Self, Self::Err> {
+		Ok(match s {
+			"no" => Self::No,
+			"yes" => Self::Yes,
+			_ => bail!("Invalid `wrap` value: {s}"),
+		})
+	}
+}
+
+impl TryFrom<String> for PreviewWrap {
+	type Error = anyhow::Error;
+
+	fn try_from(value: String) -> Result<Self, Self::Error> { Self::from_str(&value) }
+}

yazi-plugin/preset/plugins/code.lua

@@ -4,7 +4,7 @@ function M:peek()
 	local err, bound = ya.preview_code(self)
 	if bound then
 		ya.manager_emit("peek", { bound, only_if = self.file.url, upper_bound = true })
-	elseif err then
+	elseif err and not err:find("cancelled", 1, true) then
 		ya.preview_widgets(self, {
 			ui.Paragraph(self.area, { ui.Line(err):reverse() }),
 		})

yazi-plugin/preset/plugins/json.lua

@@ -56,7 +56,7 @@ function M:fallback_to_builtin()
 	local err, bound = ya.preview_code(self)
 	if bound then
 		ya.manager_emit("peek", { bound, only_if = self.file.url, upper_bound = true })
-	elseif err then
+	elseif err and not err:find("cancelled", 1, true) then
 		ya.preview_widgets(self, {
 			ui.Paragraph(self.area, { ui.Line(err):reverse() }),
 		})

yazi-plugin/src/elements/paragraph.rs

@@ -10,9 +10,9 @@ const CENTER: u8 = 1;
 const RIGHT: u8 = 2;
 
 // Wrap
-const WRAP_NO: u8 = 0;
-const WRAP: u8 = 1;
-const WRAP_TRIM: u8 = 2;
+pub const WRAP_NO: u8 = 0;
+pub const WRAP: u8 = 1;
+pub const WRAP_TRIM: u8 = 2;
 
 #[derive(Clone, Debug, Default)]
 pub struct Paragraph {
@@ -45,7 +45,7 @@ impl Paragraph {
 			("CENTER", CENTER.into_lua(lua)?),
 			("RIGHT", RIGHT.into_lua(lua)?),
 			// Wrap
-			("WRAP_OFF", WRAP_NO.into_lua(lua)?),
+			("WRAP_NO", WRAP_NO.into_lua(lua)?),
 			("WRAP", WRAP.into_lua(lua)?),
 			("WRAP_TRIM", WRAP_TRIM.into_lua(lua)?),
 		])?;

yazi-plugin/src/external/highlighter.rs

@@ -1,10 +1,10 @@
-use std::{io::Cursor, mem, path::{Path, PathBuf}, sync::atomic::{AtomicUsize, Ordering}};
+use std::{borrow::Cow, io::Cursor, mem, path::{Path, PathBuf}, sync::atomic::{AtomicUsize, Ordering}};
 
 use anyhow::{anyhow, Result};
-use ratatui::text::{Line, Span, Text};
+use ratatui::{layout::Rect, text::{Line, Span, Text}};
 use syntect::{dumps, easy::HighlightLines, highlighting::{self, Theme, ThemeSet}, parsing::{SyntaxReference, SyntaxSet}, LoadingError};
 use tokio::{fs::File, io::{AsyncBufReadExt, BufReader}, sync::OnceCell};
-use yazi_config::{PREVIEW, THEME};
+use yazi_config::{preview::PreviewWrap, PREVIEW, THEME};
 use yazi_shared::PeekError;
 
 static INCR: AtomicUsize = AtomicUsize::new(0);
@@ -41,23 +41,20 @@ impl Highlighter {
 	#[inline]
 	pub fn abort() { INCR.fetch_add(1, Ordering::Relaxed); }
 
-	pub async fn highlight(&self, skip: usize, limit: usize) -> Result<Text<'static>, PeekError> {
+	pub async fn highlight(&self, skip: usize, area: Rect) -> Result<Text<'static>, PeekError> {
 		let mut reader = BufReader::new(File::open(&self.path).await?);
 
 		let syntax = Self::find_syntax(&self.path).await;
 		let mut plain = syntax.is_err();
 
 		let mut before = Vec::with_capacity(if plain { 0 } else { skip });
-		let mut after = Vec::with_capacity(limit);
+		let mut after = Vec::with_capacity(area.height as _);
 
 		let mut i = 0;
 		let mut buf = vec![];
 		let mut inspected = 0u16;
-		while reader.read_until(b'\n', &mut buf).await.is_ok() {
-			i += 1;
-			if buf.is_empty() || i > skip + limit {
-				break;
-			} else if Self::is_binary(&buf, &mut inspected) {
+		while reader.read_until(b'\n', &mut buf).await.is_ok_and(|n| n > 0) {
+			if Self::is_binary(&buf, &mut inspected) {
 				return Err("Binary file".into());
 			}
 
@@ -72,17 +69,27 @@ impl Highlighter {
 				buf.push(b'\n');
 			}
 
-			if i > skip {
+			i += if i >= skip {
 				buf.iter_mut().for_each(Self::carriage_return_to_line_feed);
 				after.push(String::from_utf8_lossy(&buf).into_owned());
+				Self::line_height(&after[after.len() - 1], area.width)
 			} else if !plain {
 				before.push(String::from_utf8_lossy(&buf).into_owned());
-			}
+				Self::line_height(&before[before.len() - 1], area.width)
+			} else if PREVIEW.wrap == PreviewWrap::Yes {
+				Self::line_height(&String::from_utf8_lossy(&buf), area.width)
+			} else {
+				1
+			};
+
 			buf.clear();
+			if i > skip + area.height as usize {
+				break;
+			}
 		}
 
-		if skip > 0 && i < skip + limit {
-			return Err(PeekError::Exceed(i.saturating_sub(limit)));
+		if skip > 0 && i < skip + area.height as usize {
+			return Err(PeekError::Exceed(i.saturating_sub(area.height as _)));
 		}
 
 		Ok(if plain {
@@ -153,6 +160,31 @@ impl Highlighter {
 		}
 	}
 
+	fn line_height(s: &str, width: u16) -> usize {
+		if PREVIEW.wrap != PreviewWrap::Yes {
+			return 1;
+		}
+
+		let pad = PREVIEW
+			.tab_size
+			.checked_sub(1)
+			.map(|n| s.bytes().filter(|&b| b == b'\t').count() * n as usize)
+			.map(|n| yazi_config::preview::Preview::indent_with(n))
+			.unwrap_or_default();
+
+		let line = Line {
+			spans: vec![Span { content: pad, style: Default::default() }, Span {
+				content: Cow::Borrowed(s),
+				..Default::default()
+			}],
+			..Default::default()
+		};
+
+		ratatui::widgets::Paragraph::new(line)
+			.wrap(ratatui::widgets::Wrap { trim: false })
+			.line_count(width)
+	}
+
 	#[inline(always)]
 	fn carriage_return_to_line_feed(c: &mut u8) {
 		if *c == b'\r' {

yazi-plugin/src/utils/preview.rs

@@ -1,8 +1,9 @@
 use mlua::{AnyUserData, IntoLuaMulti, Lua, Table, Value};
+use yazi_config::{preview::PreviewWrap, PREVIEW};
 use yazi_shared::{emit, event::Cmd, Layer, PeekError};
 
 use super::Utils;
-use crate::{bindings::Window, cast_to_renderable, elements::{Paragraph, RectRef, Renderable}, external::Highlighter, file::FileRef};
+use crate::{bindings::Window, cast_to_renderable, elements::{Paragraph, RectRef, Renderable, WRAP, WRAP_NO}, external::Highlighter, file::FileRef};
 
 pub struct PreviewLock {
 	pub url: yazi_shared::fs::Url,
@@ -36,15 +37,20 @@ impl Utils {
 				let area: RectRef = t.raw_get("area")?;
 				let mut lock = PreviewLock::try_from(t)?;
 
-				let text =
-					match Highlighter::new(&lock.url).highlight(lock.skip, area.height as usize).await {
-						Ok(text) => text,
-						Err(e @ PeekError::Exceed(max)) => return (e.to_string(), max).into_lua_multi(lua),
-						Err(e @ PeekError::Unexpected(_)) => {
-							return (e.to_string(), Value::Nil).into_lua_multi(lua);
-						}
-					};
-				lock.data = vec![Box::new(Paragraph { area: *area, text, ..Default::default() })];
+				let text = match Highlighter::new(&lock.url).highlight(lock.skip, *area).await {
+					Ok(text) => text,
+					Err(e @ PeekError::Exceed(max)) => return (e.to_string(), max).into_lua_multi(lua),
+					Err(e @ PeekError::Unexpected(_)) => {
+						return (e.to_string(), Value::Nil).into_lua_multi(lua);
+					}
+				};
+
+				lock.data = vec![Box::new(Paragraph {
+					area: *area,
+					text,
+					wrap: if PREVIEW.wrap == PreviewWrap::Yes { WRAP } else { WRAP_NO },
+					..Default::default()
+				})];
 
 				emit!(Call(Cmd::new("preview").with_any("lock", lock), Layer::Manager));
 				(Value::Nil, Value::Nil).into_lua_multi(lua)