Do column width calculations ourselves (speedup)

Instead of stripping the ANSI formatting characters from our strings, work out the length without them and use that. This is per-column, but most of them are simple (just the same number of characters in the non-coloured string).

Sometimes, this is really simple: for example, trwxrwxrwx permissions strings are always going to be ten characters long, and the strings that get returned are chock full of ANSI escape codes.

This should have a small benefit on performance.
This commit is contained in:
Benjamin Sago 2015-01-24 17:26:26 +00:00
parent f82dc741de
commit 449592c150
3 changed files with 99 additions and 61 deletions

View File

@ -1,5 +1,7 @@
use std::iter::repeat;
use ansi_term::Style;
#[derive(PartialEq, Show)]
pub enum Column {
Permissions,
@ -79,3 +81,17 @@ impl Alignment {
}
}
}
pub struct Cell {
pub length: usize,
pub text: String,
}
impl Cell {
pub fn paint(style: Style, string: &str) -> Cell {
Cell {
text: style.paint(string).to_string(),
length: string.len(),
}
}
}

View File

@ -9,7 +9,7 @@ use users::Users;
use number_prefix::{binary_prefix, decimal_prefix, Prefixed, Standalone, PrefixNames};
use column::{Column, SizeFormat};
use column::{Column, SizeFormat, Cell};
use column::Column::*;
use dir::Dir;
use filetype::HasType;
@ -68,7 +68,7 @@ impl<'a> File<'a> {
}
/// Get the data for a column, formatted as a coloured string.
pub fn display<U: Users>(&self, column: &Column, users_cache: &mut U) -> String {
pub fn display<U: Users>(&self, column: &Column, users_cache: &mut U) -> Cell {
match *column {
Permissions => self.permissions_string(),
FileName => self.file_name_view(),
@ -86,11 +86,16 @@ impl<'a> File<'a> {
///
/// It consists of the file name coloured in the appropriate style, and,
/// if it's a symlink, an arrow pointing to the file it links to, also
/// coloured in the appropriate style. Files that don't exist will be
/// coloured red.
pub fn file_name_view(&self) -> String {
let name = self.name.as_slice();
let displayed_name = self.file_colour().paint(name);
/// coloured in the appropriate style.
///
/// If the symlink target doesn't exist, then instead of displaying
/// an error, highlight the target and arrow in red. The error would
/// be shown out of context, and it's almost always because the
/// target doesn't exist.
pub fn file_name_view(&self) -> Cell {
let name = &*self.name;
let style = self.file_colour();
if self.stat.kind == io::FileType::Symlink {
match fs::readlink(&self.path) {
Ok(path) => {
@ -98,13 +103,31 @@ impl<'a> File<'a> {
Some(dir) => dir.path.join(path),
None => path,
};
format!("{} {}", displayed_name, self.target_file_name_and_arrow(&target_path))
match self.target_file(&target_path) {
Ok(file) => Cell {
length: 0, // These lengths are never actually used...
text: format!("{} {} {}{}{}",
style.paint(name),
GREY.paint("=>"),
Cyan.paint(target_path.dirname_str().unwrap()),
Cyan.paint("/"),
file.file_colour().paint(file.name.as_slice())),
},
Err(filename) => Cell {
length: 0, // ...because the rightmost column lengths are ignored!
text: format!("{} {} {}",
style.paint(name),
Red.paint("=>"),
Red.underline().paint(filename.as_slice())),
},
}
Err(_) => displayed_name.to_string(),
}
Err(_) => Cell::paint(style, name),
}
}
else {
displayed_name.to_string()
Cell::paint(style, name)
}
}
@ -122,36 +145,35 @@ impl<'a> File<'a> {
self.name.as_slice().width(false)
}
fn target_file_name_and_arrow(&self, target_path: &Path) -> String {
/// Assuming the current file is a symlink, follows the link and
/// returns a File object from the path the link points to.
///
/// If statting the file fails (usually because the file on the
/// other end doesn't exist), returns the *filename* of the file
/// that should be there.
fn target_file(&self, target_path: &Path) -> Result<File, String> {
let v = target_path.filename().unwrap();
let filename = String::from_utf8_lossy(v);
// Use stat instead of lstat - we *want* to follow links.
let link_target = fs::stat(target_path).map(|stat| File {
if let Ok(stat) = fs::stat(target_path) {
Ok(File {
path: target_path.clone(),
dir: self.dir,
stat: stat,
name: filename.to_string(),
ext: ext(filename.as_slice()),
});
// Statting a path usually fails because the file at the
// other end doesn't exist. Show this by highlighting the
// target file in red instead of displaying an error, because
// the error would be shown out of context (before the
// results, not right by the file) and it's almost always for
// that reason anyway.
match link_target {
Ok(file) => format!("{} {}{}{}", GREY.paint("=>"), Cyan.paint(target_path.dirname_str().unwrap()), Cyan.paint("/"), file.file_colour().paint(filename.as_slice())),
Err(_) => format!("{} {}", Red.paint("=>"), Red.underline().paint(filename.as_slice())),
})
}
else {
Err(filename.to_string())
}
}
/// This file's number of hard links as a coloured string.
fn hard_links(&self) -> String {
fn hard_links(&self) -> Cell {
let style = if self.has_multiple_links() { Red.on(Yellow) } else { Red.normal() };
style.paint(self.stat.unstable.nlink.to_string().as_slice()).to_string()
Cell::paint(style, &*self.stat.unstable.nlink.to_string())
}
/// Whether this is a regular file with more than one link.
@ -164,17 +186,17 @@ impl<'a> File<'a> {
}
/// This file's inode as a coloured string.
fn inode(&self) -> String {
Purple.paint(self.stat.unstable.inode.to_string().as_slice()).to_string()
fn inode(&self) -> Cell {
Cell::paint(Purple.normal(), &*self.stat.unstable.inode.to_string())
}
/// This file's number of filesystem blocks (if available) as a coloured string.
fn blocks(&self) -> String {
fn blocks(&self) -> Cell {
if self.stat.kind == io::FileType::RegularFile || self.stat.kind == io::FileType::Symlink {
Cyan.paint(self.stat.unstable.blocks.to_string().as_slice()).to_string()
Cell::paint(Cyan.normal(), &*self.stat.unstable.blocks.to_string())
}
else {
GREY.paint("-").to_string()
Cell { text: GREY.paint("-").to_string(), length: 1 }
}
}
@ -183,7 +205,7 @@ impl<'a> File<'a> {
/// If the user is not present, then it formats the uid as a number
/// instead. This usually happens when a user is deleted, but still owns
/// files.
fn user<U: Users>(&self, users_cache: &mut U) -> String {
fn user<U: Users>(&self, users_cache: &mut U) -> Cell {
let uid = self.stat.unstable.uid as i32;
let user_name = match users_cache.get_user_by_uid(uid) {
@ -192,13 +214,13 @@ impl<'a> File<'a> {
};
let style = if users_cache.get_current_uid() == uid { Yellow.bold() } else { Plain };
style.paint(user_name.as_slice()).to_string()
Cell::paint(style, &*user_name)
}
/// This file's group name as a coloured string.
///
/// As above, if not present, it formats the gid as a number instead.
fn group<U: Users>(&self, users_cache: &mut U) -> String {
fn group<U: Users>(&self, users_cache: &mut U) -> Cell {
let gid = self.stat.unstable.gid as u32;
let mut style = Plain;
@ -215,7 +237,7 @@ impl<'a> File<'a> {
None => gid.to_string(),
};
style.paint(group_name.as_slice()).to_string()
Cell::paint(style, &*group_name)
}
/// This file's size, formatted using the given way, as a coloured string.
@ -224,22 +246,27 @@ impl<'a> File<'a> {
/// some filesystems, I've never looked at one of those numbers and gained
/// any information from it, so by emitting "-" instead, the table is less
/// cluttered with numbers.
fn file_size(&self, size_format: SizeFormat) -> String {
fn file_size(&self, size_format: SizeFormat) -> Cell {
if self.stat.kind == io::FileType::Directory {
GREY.paint("-").to_string()
Cell { text: GREY.paint("-").to_string(), length: 1 }
}
else {
let result = match size_format {
SizeFormat::DecimalBytes => decimal_prefix(self.stat.size as f64),
SizeFormat::BinaryBytes => binary_prefix(self.stat.size as f64),
SizeFormat::JustBytes => return Green.bold().paint(self.stat.size.to_string().as_slice()).to_string(),
SizeFormat::JustBytes => return Cell::paint(Green.bold(), &*self.stat.size.to_string())
};
match result {
Standalone(bytes) => Green.bold().paint(bytes.to_string().as_slice()).to_string(),
Standalone(bytes) => Cell::paint(Green.bold(), &*bytes.to_string()),
Prefixed(prefix, n) => {
let number = if n < 10f64 { format!("{:.1}", n) } else { format!("{:.0}", n) };
format!("{}{}", Green.bold().paint(number.as_slice()), Green.paint(prefix.symbol()))
let symbol = prefix.symbol();
Cell {
text: format!("{}{}", Green.bold().paint(&*number), Green.paint(symbol)),
length: number.len() + symbol.len(),
}
}
}
}
@ -265,14 +292,14 @@ impl<'a> File<'a> {
/// Each character is given its own colour. The first three permission
/// bits are bold because they're the ones used most often, and executable
/// files are underlined to make them stand out more.
fn permissions_string(&self) -> String {
fn permissions_string(&self) -> Cell {
let bits = self.stat.perm;
let executable_colour = match self.stat.kind {
io::FileType::RegularFile => Green.bold().underline(),
_ => Green.bold(),
};
return format!("{}{}{}{}{}{}{}{}{}{}",
let string = format!("{}{}{}{}{}{}{}{}{}{}",
self.type_char(),
File::permission_bit(&bits, io::USER_READ, "r", Yellow.bold()),
File::permission_bit(&bits, io::USER_WRITE, "w", Red.bold()),
@ -284,6 +311,8 @@ impl<'a> File<'a> {
File::permission_bit(&bits, io::OTHER_WRITE, "w", Red.normal()),
File::permission_bit(&bits, io::OTHER_EXECUTE, "x", Green.normal()),
);
Cell { text: string, length: 10 }
}
/// Helper method for the permissions string.

View File

@ -1,13 +1,12 @@
use std::cmp::max;
use std::iter::{AdditiveIterator, repeat};
use column::Column;
use column::{Column, Cell};
use column::Alignment::Left;
use file::File;
use users::OSUsers;
use ansi_term::Style::Plain;
use ansi_term::strip_formatting;
#[derive(PartialEq, Show)]
pub enum View {
@ -29,7 +28,7 @@ impl View {
/// The lines view literally just displays each file, line-by-line.
fn lines_view(files: Vec<File>) {
for file in files.iter() {
println!("{}", file.file_name_view());
println!("{}", file.file_name_view().text);
}
}
@ -130,22 +129,16 @@ fn details_view(columns: &Vec<Column>, files: Vec<File>, header: bool) {
let mut cache = OSUsers::empty_cache();
let mut table: Vec<Vec<String>> = files.iter()
let mut table: Vec<Vec<Cell>> = files.iter()
.map(|f| columns.iter().map(|c| f.display(c, &mut cache)).collect())
.collect();
if header {
table.insert(0, columns.iter().map(|c| Plain.underline().paint(c.header()).to_string()).collect());
table.insert(0, columns.iter().map(|c| Cell::paint(Plain.underline(), c.header())).collect());
}
// Each column needs to have its invisible colour-formatting
// characters stripped before it has its width calculated, or the
// width will be incorrect and the columns won't line up properly.
// This is fairly expensive to do (it uses a regex), so the
// results are cached.
let lengths: Vec<Vec<usize>> = table.iter()
.map(|row| row.iter().map(|col| strip_formatting(col.as_slice()).len()).collect())
.map(|row| row.iter().map(|c| c.length).collect())
.collect();
let column_widths: Vec<usize> = range(0, columns.len())
@ -160,11 +153,11 @@ fn details_view(columns: &Vec<Column>, files: Vec<File>, header: bool) {
if num == columns.len() - 1 {
// The final column doesn't need to have trailing spaces
print!("{}", row[num]);
print!("{}", row[num].text);
}
else {
let padding = column_widths[num] - field_widths[num];
print!("{}", column.alignment().pad_string(&row[num], padding));
print!("{}", column.alignment().pad_string(&row[num].text, padding));
}
}
print!("\n");