From 62fcf27dfb422f3a7101477a1cd6adc4a5884e7e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=89=E5=92=B2=E9=9B=85=20=C2=B7=20Misaki=20Masa?=
 <sxyazi@gmail.com>
Date: Wed, 14 Aug 2024 15:03:38 +0800
Subject: [PATCH] feat: new `empty` previewer for empty and `/proc` files
 (#1482)

---
 yazi-config/preset/yazi.toml         |  2 ++
 yazi-plugin/preset/plugins/empty.lua | 49 ++++++++++++++++++++++++++++
 yazi-plugin/src/elements/span.rs     |  4 +++
 yazi-plugin/src/elements/style.rs    |  4 +++
 yazi-plugin/src/isolate/peek.rs      |  2 +-
 yazi-plugin/src/loader/loader.rs     |  6 ++--
 6 files changed, 64 insertions(+), 3 deletions(-)
 create mode 100644 yazi-plugin/preset/plugins/empty.lua

diff --git a/yazi-config/preset/yazi.toml b/yazi-config/preset/yazi.toml
index cd8a3f52..d21cfb07 100644
--- a/yazi-config/preset/yazi.toml
+++ b/yazi-config/preset/yazi.toml
@@ -122,6 +122,8 @@ previewers = [
 	# Font
 	{ mime = "font/*", run = "font" },
 	{ mime = "application/vnd.ms-opentype", run = "font" },
+	# Empty file
+	{ mime = "inode/x-empty", run = "empty" },
 	# Fallback
 	{ name = "*", run = "file" },
 ]
diff --git a/yazi-plugin/preset/plugins/empty.lua b/yazi-plugin/preset/plugins/empty.lua
new file mode 100644
index 00000000..5d2e9b46
--- /dev/null
+++ b/yazi-plugin/preset/plugins/empty.lua
@@ -0,0 +1,49 @@
+local M = {}
+
+function M:msg(s)
+	local p = ui.Paragraph(self.area, {
+		ui.Line { ui.Span(s):reverse() },
+	})
+	ya.preview_widgets(self, { p:wrap(ui.Paragraph.WRAP) })
+end
+
+function M:peek()
+	local path = tostring(self.file.url)
+	if path:sub(1, 6) ~= "/proc/" then
+		return self:msg("Empty file")
+	end
+
+	local limit = self.area.h
+	local i, lines = 0, {}
+	local ok, err = pcall(function()
+		for line in io.lines(path) do
+			i = i + 1
+			if i > self.skip + limit then
+				break
+			elseif i > self.skip then
+				lines[#lines + 1] = ui.Line(line)
+			end
+		end
+	end)
+
+	if not ok then
+		self:msg(err)
+	elseif self.skip > 0 and i < self.skip + limit then
+		ya.manager_emit("peek", { math.max(0, i - limit), only_if = self.file.url, upper_bound = true })
+	else
+		ya.preview_widgets(self, { ui.Paragraph(self.area, lines) })
+	end
+end
+
+function M:seek(units)
+	local h = cx.active.current.hovered
+	if h and h.url == self.file.url then
+		local step = math.floor(units * self.area.h / 10)
+		ya.manager_emit("peek", {
+			math.max(0, cx.active.preview.skip + step),
+			only_if = self.file.url,
+		})
+	end
+end
+
+return M
diff --git a/yazi-plugin/src/elements/span.rs b/yazi-plugin/src/elements/span.rs
index 96549f3c..1fa7a8ff 100644
--- a/yazi-plugin/src/elements/span.rs
+++ b/yazi-plugin/src/elements/span.rs
@@ -51,6 +51,10 @@ impl UserData for Span {
 			ud.borrow_mut::<Self>()?.0.style.add_modifier |= ratatui::style::Modifier::RAPID_BLINK;
 			Ok(ud)
 		});
+		methods.add_function("reverse", |_, ud: AnyUserData| {
+			ud.borrow_mut::<Self>()?.0.style.add_modifier |= ratatui::style::Modifier::REVERSED;
+			Ok(ud)
+		});
 		methods.add_function("hidden", |_, ud: AnyUserData| {
 			ud.borrow_mut::<Self>()?.0.style.add_modifier |= ratatui::style::Modifier::HIDDEN;
 			Ok(ud)
diff --git a/yazi-plugin/src/elements/style.rs b/yazi-plugin/src/elements/style.rs
index 67070b99..d58fef18 100644
--- a/yazi-plugin/src/elements/style.rs
+++ b/yazi-plugin/src/elements/style.rs
@@ -72,6 +72,10 @@ impl UserData for Style {
 			ud.borrow_mut::<Self>()?.0.add_modifier |= ratatui::style::Modifier::RAPID_BLINK;
 			Ok(ud)
 		});
+		methods.add_function("reverse", |_, ud: AnyUserData| {
+			ud.borrow_mut::<Self>()?.0.add_modifier |= ratatui::style::Modifier::REVERSED;
+			Ok(ud)
+		});
 		methods.add_function("hidden", |_, ud: AnyUserData| {
 			ud.borrow_mut::<Self>()?.0.add_modifier |= ratatui::style::Modifier::HIDDEN;
 			Ok(ud)
diff --git a/yazi-plugin/src/isolate/peek.rs b/yazi-plugin/src/isolate/peek.rs
index 15dd725c..e6a0d4be 100644
--- a/yazi-plugin/src/isolate/peek.rs
+++ b/yazi-plugin/src/isolate/peek.rs
@@ -47,7 +47,7 @@ pub fn peek(cmd: &Cmd, file: yazi_shared::fs::File, skip: usize) -> Cancellation
 
 		if let Err(e) = result {
 			if !e.to_string().contains("Peek task cancelled") {
-				error!("{e}");
+				error!("{e:?}");
 			}
 		}
 	});
diff --git a/yazi-plugin/src/loader/loader.rs b/yazi-plugin/src/loader/loader.rs
index 9a551253..fcfc01a6 100644
--- a/yazi-plugin/src/loader/loader.rs
+++ b/yazi-plugin/src/loader/loader.rs
@@ -1,6 +1,6 @@
 use std::{borrow::Cow, collections::HashMap, ops::Deref};
 
-use anyhow::Result;
+use anyhow::{Context, Result};
 use mlua::{ExternalError, Lua, Table};
 use parking_lot::RwLock;
 use tokio::fs;
@@ -24,6 +24,7 @@ impl Loader {
 			"archive" => &include_bytes!("../../preset/plugins/archive.lua")[..],
 			"code" => include_bytes!("../../preset/plugins/code.lua"),
 			"dds" => include_bytes!("../../preset/plugins/dds.lua"),
+			"empty" => include_bytes!("../../preset/plugins/empty.lua"),
 			"extract" => include_bytes!("../../preset/plugins/extract.lua"),
 			"file" => include_bytes!("../../preset/plugins/file.lua"),
 			"folder" => include_bytes!("../../preset/plugins/folder.lua"),
@@ -42,7 +43,8 @@ impl Loader {
 		};
 
 		let b = if preset.is_empty() {
-			Cow::Owned(fs::read(BOOT.plugin_dir.join(format!("{name}.yazi/init.lua"))).await?)
+			let p = BOOT.plugin_dir.join(format!("{name}.yazi/init.lua"));
+			Cow::Owned(fs::read(&p).await.with_context(|| format!("failed to load plugin from {p:?}"))?)
 		} else {
 			Cow::Borrowed(preset)
 		};