blob: eb53bfa5451c6faeb21f0fea02ac8ce3c6d6bf4b [file] [log] [blame]
// Std
use std::borrow::Cow;
use std::cmp;
use std::fmt::Write as _;
use std::io::{self, Write};
use std::usize;
// Internal
use crate::builder::{display_arg_val, Arg, Command};
use crate::output::{fmt::Colorizer, Usage};
use crate::PossibleValue;
// Third party
use indexmap::IndexSet;
use textwrap::core::display_width;
/// `clap` Help Writer.
///
/// Wraps a writer stream providing different methods to generate help for `clap` objects.
pub(crate) struct Help<'help, 'cmd, 'writer> {
writer: HelpWriter<'writer>,
cmd: &'cmd Command<'help>,
usage: &'cmd Usage<'help, 'cmd>,
next_line_help: bool,
term_w: usize,
use_long: bool,
}
// Public Functions
impl<'help, 'cmd, 'writer> Help<'help, 'cmd, 'writer> {
#[cfg(feature = "unstable-v4")]
const DEFAULT_TEMPLATE: &'static str = "\
{before-help}{name} {version}\n\
{author-with-newline}{about-with-newline}\n\
{usage-heading}\n {usage}\n\
\n\
{all-args}{after-help}\
";
#[cfg(not(feature = "unstable-v4"))]
const DEFAULT_TEMPLATE: &'static str = "\
{before-help}{bin} {version}\n\
{author-with-newline}{about-with-newline}\n\
{usage-heading}\n {usage}\n\
\n\
{all-args}{after-help}\
";
#[cfg(feature = "unstable-v4")]
const DEFAULT_NO_ARGS_TEMPLATE: &'static str = "\
{before-help}{name} {version}\n\
{author-with-newline}{about-with-newline}\n\
{usage-heading}\n {usage}{after-help}\
";
#[cfg(not(feature = "unstable-v4"))]
const DEFAULT_NO_ARGS_TEMPLATE: &'static str = "\
{before-help}{bin} {version}\n\
{author-with-newline}{about-with-newline}\n\
{usage-heading}\n {usage}{after-help}\
";
/// Create a new `Help` instance.
pub(crate) fn new(
writer: HelpWriter<'writer>,
cmd: &'cmd Command<'help>,
usage: &'cmd Usage<'help, 'cmd>,
use_long: bool,
) -> Self {
debug!("Help::new cmd={}, use_long={}", cmd.get_name(), use_long);
let term_w = match cmd.get_term_width() {
Some(0) => usize::MAX,
Some(w) => w,
None => cmp::min(
dimensions().map_or(100, |(w, _)| w),
match cmd.get_max_term_width() {
None | Some(0) => usize::MAX,
Some(mw) => mw,
},
),
};
let next_line_help = cmd.is_next_line_help_set();
Help {
writer,
cmd,
usage,
next_line_help,
term_w,
use_long,
}
}
/// Writes the parser help to the wrapped stream.
pub(crate) fn write_help(&mut self) -> io::Result<()> {
debug!("Help::write_help");
if let Some(h) = self.cmd.get_override_help() {
self.none(h)?;
} else if let Some(tmpl) = self.cmd.get_help_template() {
self.write_templated_help(tmpl)?;
} else {
let pos = self
.cmd
.get_positionals()
.any(|arg| should_show_arg(self.use_long, arg));
let non_pos = self
.cmd
.get_non_positionals()
.any(|arg| should_show_arg(self.use_long, arg));
let subcmds = self.cmd.has_visible_subcommands();
if non_pos || pos || subcmds {
self.write_templated_help(Self::DEFAULT_TEMPLATE)?;
} else {
self.write_templated_help(Self::DEFAULT_NO_ARGS_TEMPLATE)?;
}
}
self.none("\n")?;
Ok(())
}
}
macro_rules! write_method {
($_self:ident, $msg:ident, $meth:ident) => {
match &mut $_self.writer {
HelpWriter::Buffer(c) => {
c.$meth(($msg).into());
Ok(())
}
HelpWriter::Normal(w) => w.write_all($msg.as_ref()),
}
};
}
// Methods to write Arg help.
impl<'help, 'cmd, 'writer> Help<'help, 'cmd, 'writer> {
#[inline(never)]
fn good<T: Into<String> + AsRef<[u8]>>(&mut self, msg: T) -> io::Result<()> {
write_method!(self, msg, good)
}
#[inline(never)]
fn warning<T: Into<String> + AsRef<[u8]>>(&mut self, msg: T) -> io::Result<()> {
write_method!(self, msg, warning)
}
#[inline(never)]
fn none<T: Into<String> + AsRef<[u8]>>(&mut self, msg: T) -> io::Result<()> {
write_method!(self, msg, none)
}
#[inline(never)]
fn spaces(&mut self, n: usize) -> io::Result<()> {
// A string with 64 consecutive spaces.
const SHORT_SPACE: &str =
" ";
if let Some(short) = SHORT_SPACE.get(..n) {
self.none(short)
} else {
self.none(" ".repeat(n))
}
}
/// Writes help for each argument in the order they were declared to the wrapped stream.
fn write_args_unsorted(&mut self, args: &[&Arg<'help>]) -> io::Result<()> {
debug!("Help::write_args_unsorted");
// The shortest an arg can legally be is 2 (i.e. '-x')
let mut longest = 2;
let mut arg_v = Vec::with_capacity(10);
for &arg in args
.iter()
.filter(|arg| should_show_arg(self.use_long, *arg))
{
if arg.longest_filter() {
longest = longest.max(display_width(&arg.to_string()));
debug!(
"Help::write_args_unsorted: arg={:?} longest={}",
arg.get_id(),
longest
);
}
arg_v.push(arg)
}
let next_line_help = self.will_args_wrap(args, longest);
let argc = arg_v.len();
for (i, arg) in arg_v.iter().enumerate() {
self.write_arg(arg, i + 1 == argc, next_line_help, longest)?;
}
Ok(())
}
/// Sorts arguments by length and display order and write their help to the wrapped stream.
fn write_args(&mut self, args: &[&Arg<'help>], _category: &str) -> io::Result<()> {
debug!("Help::write_args {}", _category);
// The shortest an arg can legally be is 2 (i.e. '-x')
let mut longest = 2;
let mut ord_v = Vec::new();
// Determine the longest
for &arg in args.iter().filter(|arg| {
// If it's NextLineHelp we don't care to compute how long it is because it may be
// NextLineHelp on purpose simply *because* it's so long and would throw off all other
// args alignment
should_show_arg(self.use_long, *arg)
}) {
if arg.longest_filter() {
longest = longest.max(display_width(&arg.to_string()));
debug!(
"Help::write_args: arg={:?} longest={}",
arg.get_id(),
longest
);
}
// Formatting key like this to ensure that:
// 1. Argument has long flags are printed just after short flags.
// 2. For two args both have short flags like `-c` and `-C`, the
// `-C` arg is printed just after the `-c` arg
// 3. For args without short or long flag, print them at last(sorted
// by arg name).
// Example order: -a, -b, -B, -s, --select-file, --select-folder, -x
let key = if let Some(x) = arg.short {
let mut s = x.to_ascii_lowercase().to_string();
s.push(if x.is_ascii_lowercase() { '0' } else { '1' });
s
} else if let Some(x) = arg.long {
x.to_string()
} else {
let mut s = '{'.to_string();
s.push_str(arg.name);
s
};
ord_v.push((arg.get_display_order(), key, arg));
}
ord_v.sort_by(|a, b| (a.0, &a.1).cmp(&(b.0, &b.1)));
let next_line_help = self.will_args_wrap(args, longest);
for (i, (_, _, arg)) in ord_v.iter().enumerate() {
let last_arg = i + 1 == ord_v.len();
self.write_arg(arg, last_arg, next_line_help, longest)?;
}
Ok(())
}
/// Writes help for an argument to the wrapped stream.
fn write_arg(
&mut self,
arg: &Arg<'help>,
last_arg: bool,
next_line_help: bool,
longest: usize,
) -> io::Result<()> {
let spec_vals = &self.spec_vals(arg);
self.short(arg)?;
self.long(arg)?;
self.val(arg)?;
self.align_to_about(arg, next_line_help, longest)?;
let about = if self.use_long {
arg.long_help.or(arg.help).unwrap_or("")
} else {
arg.help.or(arg.long_help).unwrap_or("")
};
self.help(Some(arg), about, spec_vals, next_line_help, longest)?;
if !last_arg {
self.none("\n")?;
if next_line_help {
self.none("\n")?;
}
}
Ok(())
}
/// Writes argument's short command to the wrapped stream.
fn short(&mut self, arg: &Arg<'help>) -> io::Result<()> {
debug!("Help::short");
self.none(TAB)?;
if let Some(s) = arg.short {
self.good(format!("-{}", s))
} else if !arg.is_positional() {
self.none(TAB)
} else {
Ok(())
}
}
/// Writes argument's long command to the wrapped stream.
fn long(&mut self, arg: &Arg<'help>) -> io::Result<()> {
debug!("Help::long");
if let Some(long) = arg.long {
if arg.short.is_some() {
self.none(", ")?;
}
self.good(format!("--{}", long))?;
}
Ok(())
}
/// Writes argument's possible values to the wrapped stream.
fn val(&mut self, arg: &Arg<'help>) -> io::Result<()> {
debug!("Help::val: arg={}", arg.name);
let mut need_closing_bracket = false;
if arg.is_takes_value_set() && !arg.is_positional() {
let is_optional_val = arg.min_vals == Some(0);
let sep = if arg.is_require_equals_set() {
if is_optional_val {
need_closing_bracket = true;
"[="
} else {
"="
}
} else if is_optional_val {
need_closing_bracket = true;
" ["
} else {
" "
};
self.none(sep)?;
}
if arg.is_takes_value_set() || arg.is_positional() {
display_arg_val(
arg,
|s, good| if good { self.good(s) } else { self.none(s) },
)?;
}
if need_closing_bracket {
self.none("]")?;
}
Ok(())
}
/// Write alignment padding between arg's switches/values and its about message.
fn align_to_about(
&mut self,
arg: &Arg<'help>,
next_line_help: bool,
longest: usize,
) -> io::Result<()> {
debug!(
"Help::align_to_about: arg={}, next_line_help={}, longest={}",
arg.name, next_line_help, longest
);
if self.use_long || next_line_help {
// long help prints messages on the next line so it doesn't need to align text
debug!("Help::align_to_about: printing long help so skip alignment");
} else if !arg.is_positional() {
let self_len = display_width(&arg.to_string());
// Since we're writing spaces from the tab point we first need to know if we
// had a long and short, or just short
let padding = if arg.long.is_some() {
// Only account 4 after the val
4
} else {
// Only account for ', --' + 4 after the val
8
};
let spcs = longest + padding - self_len;
debug!(
"Help::align_to_about: positional=false arg_len={}, spaces={}",
self_len, spcs
);
self.spaces(spcs)?;
} else {
let self_len = display_width(&arg.to_string());
let padding = 4;
let spcs = longest + padding - self_len;
debug!(
"Help::align_to_about: positional=true arg_len={}, spaces={}",
self_len, spcs
);
self.spaces(spcs)?;
}
Ok(())
}
fn write_before_help(&mut self) -> io::Result<()> {
debug!("Help::write_before_help");
let before_help = if self.use_long {
self.cmd
.get_before_long_help()
.or_else(|| self.cmd.get_before_help())
} else {
self.cmd.get_before_help()
};
if let Some(output) = before_help {
self.none(text_wrapper(&output.replace("{n}", "\n"), self.term_w))?;
self.none("\n\n")?;
}
Ok(())
}
fn write_after_help(&mut self) -> io::Result<()> {
debug!("Help::write_after_help");
let after_help = if self.use_long {
self.cmd
.get_after_long_help()
.or_else(|| self.cmd.get_after_help())
} else {
self.cmd.get_after_help()
};
if let Some(output) = after_help {
self.none("\n\n")?;
self.none(text_wrapper(&output.replace("{n}", "\n"), self.term_w))?;
}
Ok(())
}
/// Writes argument's help to the wrapped stream.
fn help(
&mut self,
arg: Option<&Arg<'help>>,
about: &str,
spec_vals: &str,
next_line_help: bool,
longest: usize,
) -> io::Result<()> {
debug!("Help::help");
let mut help = String::from(about) + spec_vals;
debug!("Help::help: Next Line...{:?}", next_line_help);
let spaces = if next_line_help {
12 // "tab" * 3
} else {
longest + 12
};
let too_long = spaces + display_width(&help) >= self.term_w;
// Is help on next line, if so then indent
if next_line_help {
self.none(format!("\n{}{}{}", TAB, TAB, TAB))?;
}
debug!("Help::help: Too long...");
if too_long && spaces <= self.term_w || help.contains("{n}") {
debug!("Yes");
debug!("Help::help: help...{}", help);
debug!("Help::help: help width...{}", display_width(&help));
// Determine how many newlines we need to insert
let avail_chars = self.term_w - spaces;
debug!("Help::help: Usable space...{}", avail_chars);
help = text_wrapper(&help.replace("{n}", "\n"), avail_chars);
} else {
debug!("No");
}
if let Some(part) = help.lines().next() {
self.none(part)?;
}
// indent of help
let spaces = if next_line_help {
TAB_WIDTH * 3
} else if let Some(true) = arg.map(|a| a.is_positional()) {
longest + TAB_WIDTH * 2
} else {
longest + TAB_WIDTH * 3
};
for part in help.lines().skip(1) {
self.none("\n")?;
self.spaces(spaces)?;
self.none(part)?;
}
#[cfg(feature = "unstable-v4")]
if let Some(arg) = arg {
const DASH_SPACE: usize = "- ".len();
const COLON_SPACE: usize = ": ".len();
let possible_vals = arg.get_possible_values2();
if self.use_long
&& !arg.is_hide_possible_values_set()
&& possible_vals.iter().any(PossibleValue::should_show_help)
{
debug!("Help::help: Found possible vals...{:?}", possible_vals);
if !help.is_empty() {
self.none("\n\n")?;
self.spaces(spaces)?;
}
self.none("Possible values:")?;
let longest = possible_vals
.iter()
.filter_map(|f| f.get_visible_quoted_name().map(|name| display_width(&name)))
.max()
.expect("Only called with possible value");
let help_longest = possible_vals
.iter()
.filter_map(|f| f.get_visible_help().map(display_width))
.max()
.expect("Only called with possible value with help");
// should new line
let taken = longest + spaces + DASH_SPACE;
let possible_value_new_line =
self.term_w >= taken && self.term_w < taken + COLON_SPACE + help_longest;
let spaces = spaces + TAB_WIDTH - DASH_SPACE;
let spaces_help = if possible_value_new_line {
spaces + DASH_SPACE
} else {
spaces + longest + DASH_SPACE + COLON_SPACE
};
for pv in possible_vals.iter().filter(|pv| !pv.is_hide_set()) {
self.none("\n")?;
self.spaces(spaces)?;
self.none("- ")?;
self.good(pv.get_name())?;
if let Some(help) = pv.get_help() {
debug!("Help::help: Possible Value help");
if possible_value_new_line {
self.none(":\n")?;
self.spaces(spaces_help)?;
} else {
self.none(": ")?;
// To align help messages
self.spaces(longest - display_width(pv.get_name()))?;
}
let avail_chars = if self.term_w > spaces_help {
self.term_w - spaces_help
} else {
usize::MAX
};
let help = text_wrapper(help, avail_chars);
let mut help = help.lines();
self.none(help.next().unwrap_or_default())?;
for part in help {
self.none("\n")?;
self.spaces(spaces_help)?;
self.none(part)?;
}
}
}
}
}
Ok(())
}
/// Will use next line help on writing args.
fn will_args_wrap(&self, args: &[&Arg<'help>], longest: usize) -> bool {
args.iter()
.filter(|arg| should_show_arg(self.use_long, *arg))
.any(|arg| {
let spec_vals = &self.spec_vals(arg);
self.arg_next_line_help(arg, spec_vals, longest)
})
}
fn arg_next_line_help(&self, arg: &Arg<'help>, spec_vals: &str, longest: usize) -> bool {
if self.next_line_help || arg.is_next_line_help_set() || self.use_long {
// setting_next_line
true
} else {
// force_next_line
let h = arg.help.unwrap_or("");
let h_w = display_width(h) + display_width(spec_vals);
let taken = longest + 12;
self.term_w >= taken
&& (taken as f32 / self.term_w as f32) > 0.40
&& h_w > (self.term_w - taken)
}
}
fn spec_vals(&self, a: &Arg) -> String {
debug!("Help::spec_vals: a={}", a);
let mut spec_vals = vec![];
#[cfg(feature = "env")]
if let Some(ref env) = a.env {
if !a.is_hide_env_set() {
debug!(
"Help::spec_vals: Found environment variable...[{:?}:{:?}]",
env.0, env.1
);
let env_val = if !a.is_hide_env_values_set() {
format!(
"={}",
env.1
.as_ref()
.map_or(Cow::Borrowed(""), |val| val.to_string_lossy())
)
} else {
String::new()
};
let env_info = format!("[env: {}{}]", env.0.to_string_lossy(), env_val);
spec_vals.push(env_info);
}
}
if a.is_takes_value_set() && !a.is_hide_default_value_set() && !a.default_vals.is_empty() {
debug!(
"Help::spec_vals: Found default value...[{:?}]",
a.default_vals
);
let pvs = a
.default_vals
.iter()
.map(|&pvs| pvs.to_string_lossy())
.map(|pvs| {
if pvs.contains(char::is_whitespace) {
Cow::from(format!("{:?}", pvs))
} else {
pvs
}
})
.collect::<Vec<_>>()
.join(" ");
spec_vals.push(format!("[default: {}]", pvs));
}
if !a.aliases.is_empty() {
debug!("Help::spec_vals: Found aliases...{:?}", a.aliases);
let als = a
.aliases
.iter()
.filter(|&als| als.1) // visible
.map(|&als| als.0) // name
.collect::<Vec<_>>()
.join(", ");
if !als.is_empty() {
spec_vals.push(format!("[aliases: {}]", als));
}
}
if !a.short_aliases.is_empty() {
debug!(
"Help::spec_vals: Found short aliases...{:?}",
a.short_aliases
);
let als = a
.short_aliases
.iter()
.filter(|&als| als.1) // visible
.map(|&als| als.0.to_string()) // name
.collect::<Vec<_>>()
.join(", ");
if !als.is_empty() {
spec_vals.push(format!("[short aliases: {}]", als));
}
}
let possible_vals = a.get_possible_values2();
if !(a.is_hide_possible_values_set()
|| possible_vals.is_empty()
|| cfg!(feature = "unstable-v4")
&& self.use_long
&& possible_vals.iter().any(PossibleValue::should_show_help))
{
debug!("Help::spec_vals: Found possible vals...{:?}", possible_vals);
let pvs = possible_vals
.iter()
.filter_map(PossibleValue::get_visible_quoted_name)
.collect::<Vec<_>>()
.join(", ");
spec_vals.push(format!("[possible values: {}]", pvs));
}
let connector = if self.use_long { "\n" } else { " " };
let prefix = if !spec_vals.is_empty() && !a.get_help().unwrap_or("").is_empty() {
if self.use_long {
"\n\n"
} else {
" "
}
} else {
""
};
prefix.to_string() + &spec_vals.join(connector)
}
fn write_about(&mut self, before_new_line: bool, after_new_line: bool) -> io::Result<()> {
let about = if self.use_long {
self.cmd.get_long_about().or_else(|| self.cmd.get_about())
} else {
self.cmd.get_about()
};
if let Some(output) = about {
if before_new_line {
self.none("\n")?;
}
self.none(text_wrapper(output, self.term_w))?;
if after_new_line {
self.none("\n")?;
}
}
Ok(())
}
fn write_author(&mut self, before_new_line: bool, after_new_line: bool) -> io::Result<()> {
if let Some(author) = self.cmd.get_author() {
if before_new_line {
self.none("\n")?;
}
self.none(text_wrapper(author, self.term_w))?;
if after_new_line {
self.none("\n")?;
}
}
Ok(())
}
fn write_version(&mut self) -> io::Result<()> {
let version = self
.cmd
.get_version()
.or_else(|| self.cmd.get_long_version());
if let Some(output) = version {
self.none(text_wrapper(output, self.term_w))?;
}
Ok(())
}
}
/// Methods to write a single subcommand
impl<'help, 'cmd, 'writer> Help<'help, 'cmd, 'writer> {
fn write_subcommand(
&mut self,
sc_str: &str,
cmd: &Command<'help>,
next_line_help: bool,
longest: usize,
) -> io::Result<()> {
debug!("Help::write_subcommand");
let spec_vals = &self.sc_spec_vals(cmd);
let about = cmd
.get_about()
.or_else(|| cmd.get_long_about())
.unwrap_or("");
self.subcmd(sc_str, next_line_help, longest)?;
self.help(None, about, spec_vals, next_line_help, longest)
}
fn sc_spec_vals(&self, a: &Command) -> String {
debug!("Help::sc_spec_vals: a={}", a.get_name());
let mut spec_vals = vec![];
if 0 < a.get_all_aliases().count() || 0 < a.get_all_short_flag_aliases().count() {
debug!(
"Help::spec_vals: Found aliases...{:?}",
a.get_all_aliases().collect::<Vec<_>>()
);
debug!(
"Help::spec_vals: Found short flag aliases...{:?}",
a.get_all_short_flag_aliases().collect::<Vec<_>>()
);
let mut short_als = a
.get_visible_short_flag_aliases()
.map(|a| format!("-{}", a))
.collect::<Vec<_>>();
let als = a.get_visible_aliases().map(|s| s.to_string());
short_als.extend(als);
let all_als = short_als.join(", ");
if !all_als.is_empty() {
spec_vals.push(format!(" [aliases: {}]", all_als));
}
}
spec_vals.join(" ")
}
fn subcommand_next_line_help(
&self,
cmd: &Command<'help>,
spec_vals: &str,
longest: usize,
) -> bool {
if self.next_line_help | self.use_long {
// setting_next_line
true
} else {
// force_next_line
let h = cmd.get_about().unwrap_or("");
let h_w = display_width(h) + display_width(spec_vals);
let taken = longest + 12;
self.term_w >= taken
&& (taken as f32 / self.term_w as f32) > 0.40
&& h_w > (self.term_w - taken)
}
}
/// Writes subcommand to the wrapped stream.
fn subcmd(&mut self, sc_str: &str, next_line_help: bool, longest: usize) -> io::Result<()> {
self.none(TAB)?;
self.good(sc_str)?;
if !next_line_help {
let width = display_width(sc_str);
self.spaces(width.max(longest + 4) - width)?;
}
Ok(())
}
}
// Methods to write Parser help.
impl<'help, 'cmd, 'writer> Help<'help, 'cmd, 'writer> {
/// Writes help for all arguments (options, flags, args, subcommands)
/// including titles of a Parser Object to the wrapped stream.
pub(crate) fn write_all_args(&mut self) -> io::Result<()> {
debug!("Help::write_all_args");
let pos = self
.cmd
.get_positionals_with_no_heading()
.filter(|arg| should_show_arg(self.use_long, arg))
.collect::<Vec<_>>();
let non_pos = self
.cmd
.get_non_positionals_with_no_heading()
.filter(|arg| should_show_arg(self.use_long, arg))
.collect::<Vec<_>>();
let subcmds = self.cmd.has_visible_subcommands();
let custom_headings = self
.cmd
.get_arguments()
.filter_map(|arg| arg.get_help_heading())
.collect::<IndexSet<_>>();
let mut first = if !pos.is_empty() {
// Write positional args if any
self.warning("ARGS:\n")?;
self.write_args_unsorted(&pos)?;
false
} else {
true
};
if !non_pos.is_empty() {
if !first {
self.none("\n\n")?;
}
self.warning("OPTIONS:\n")?;
self.write_args(&non_pos, "OPTIONS")?;
first = false;
}
if !custom_headings.is_empty() {
for heading in custom_headings {
let args = self
.cmd
.get_arguments()
.filter(|a| {
if let Some(help_heading) = a.get_help_heading() {
return help_heading == heading;
}
false
})
.filter(|arg| should_show_arg(self.use_long, arg))
.collect::<Vec<_>>();
if !args.is_empty() {
if !first {
self.none("\n\n")?;
}
self.warning(format!("{}:\n", heading))?;
self.write_args(&args, heading)?;
first = false
}
}
}
if subcmds {
if !first {
self.none("\n\n")?;
}
self.warning(
self.cmd
.get_subcommand_help_heading()
.unwrap_or("SUBCOMMANDS"),
)?;
self.warning(":\n")?;
self.write_subcommands(self.cmd)?;
}
Ok(())
}
/// Will use next line help on writing subcommands.
fn will_subcommands_wrap<'a>(
&self,
subcommands: impl IntoIterator<Item = &'a Command<'help>>,
longest: usize,
) -> bool
where
'help: 'a,
{
subcommands
.into_iter()
.filter(|&subcommand| should_show_subcommand(subcommand))
.any(|subcommand| {
let spec_vals = &self.sc_spec_vals(subcommand);
self.subcommand_next_line_help(subcommand, spec_vals, longest)
})
}
/// Writes help for subcommands of a Parser Object to the wrapped stream.
fn write_subcommands(&mut self, cmd: &Command<'help>) -> io::Result<()> {
debug!("Help::write_subcommands");
// The shortest an arg can legally be is 2 (i.e. '-x')
let mut longest = 2;
let mut ord_v = Vec::new();
for subcommand in cmd
.get_subcommands()
.filter(|subcommand| should_show_subcommand(subcommand))
{
let mut sc_str = String::new();
sc_str.push_str(subcommand.get_name());
if let Some(short) = subcommand.get_short_flag() {
write!(sc_str, " -{}", short).unwrap();
}
if let Some(long) = subcommand.get_long_flag() {
write!(sc_str, " --{}", long).unwrap();
}
longest = longest.max(display_width(&sc_str));
ord_v.push((subcommand.get_display_order(), sc_str, subcommand));
}
ord_v.sort_by(|a, b| (a.0, &a.1).cmp(&(b.0, &b.1)));
debug!("Help::write_subcommands longest = {}", longest);
let next_line_help = self.will_subcommands_wrap(cmd.get_subcommands(), longest);
let mut first = true;
for (_, sc_str, sc) in &ord_v {
if first {
first = false;
} else {
self.none("\n")?;
}
self.write_subcommand(sc_str, sc, next_line_help, longest)?;
}
Ok(())
}
/// Writes binary name of a Parser Object to the wrapped stream.
fn write_display_name(&mut self) -> io::Result<()> {
debug!("Help::write_display_name");
let display_name = text_wrapper(
&self
.cmd
.get_display_name()
.unwrap_or_else(|| self.cmd.get_name())
.replace("{n}", "\n"),
self.term_w,
);
self.good(&display_name)?;
Ok(())
}
/// Writes binary name of a Parser Object to the wrapped stream.
fn write_bin_name(&mut self) -> io::Result<()> {
debug!("Help::write_bin_name");
let bin_name = if let Some(bn) = self.cmd.get_bin_name() {
if bn.contains(' ') {
// In case we're dealing with subcommands i.e. git mv is translated to git-mv
bn.replace(' ', "-")
} else {
text_wrapper(&self.cmd.get_name().replace("{n}", "\n"), self.term_w)
}
} else {
text_wrapper(&self.cmd.get_name().replace("{n}", "\n"), self.term_w)
};
self.good(&bin_name)?;
Ok(())
}
}
// Methods to write Parser help using templates.
impl<'help, 'cmd, 'writer> Help<'help, 'cmd, 'writer> {
/// Write help to stream for the parser in the format defined by the template.
///
/// For details about the template language see [`Command::help_template`].
///
/// [`Command::help_template`]: Command::help_template()
fn write_templated_help(&mut self, template: &str) -> io::Result<()> {
debug!("Help::write_templated_help");
// The strategy is to copy the template from the reader to wrapped stream
// until a tag is found. Depending on its value, the appropriate content is copied
// to the wrapped stream.
// The copy from template is then resumed, repeating this sequence until reading
// the complete template.
macro_rules! tags {
(
match $part:ident {
$( $tag:expr => $action:stmt )*
}
) => {
match $part {
$(
part if part.starts_with(concat!($tag, "}")) => {
$action
let rest = &part[$tag.len()+1..];
self.none(rest)?;
}
)*
// Unknown tag, write it back.
part => {
self.none("{")?;
self.none(part)?;
}
}
};
}
let mut parts = template.split('{');
if let Some(first) = parts.next() {
self.none(first)?;
}
for part in parts {
tags! {
match part {
"name" => {
self.write_display_name()?;
}
"bin" => {
self.write_bin_name()?;
}
"version" => {
self.write_version()?;
}
"author" => {
self.write_author(false, false)?;
}
"author-with-newline" => {
self.write_author(false, true)?;
}
"author-section" => {
self.write_author(true, true)?;
}
"about" => {
self.write_about(false, false)?;
}
"about-with-newline" => {
self.write_about(false, true)?;
}
"about-section" => {
self.write_about(true, true)?;
}
"usage-heading" => {
self.warning("USAGE:")?;
}
"usage" => {
self.none(self.usage.create_usage_no_title(&[]))?;
}
"all-args" => {
self.write_all_args()?;
}
"options" => {
// Include even those with a heading as we don't have a good way of
// handling help_heading in the template.
self.write_args(&self.cmd.get_non_positionals().collect::<Vec<_>>(), "options")?;
}
"positionals" => {
self.write_args(&self.cmd.get_positionals().collect::<Vec<_>>(), "positionals")?;
}
"subcommands" => {
self.write_subcommands(self.cmd)?;
}
"after-help" => {
self.write_after_help()?;
}
"before-help" => {
self.write_before_help()?;
}
}
}
}
Ok(())
}
}
pub(crate) fn dimensions() -> Option<(usize, usize)> {
#[cfg(not(feature = "wrap_help"))]
return None;
#[cfg(feature = "wrap_help")]
terminal_size::terminal_size().map(|(w, h)| (w.0.into(), h.0.into()))
}
const TAB: &str = " ";
const TAB_WIDTH: usize = 4;
pub(crate) enum HelpWriter<'writer> {
Normal(&'writer mut dyn Write),
Buffer(&'writer mut Colorizer),
}
fn should_show_arg(use_long: bool, arg: &Arg) -> bool {
debug!("should_show_arg: use_long={:?}, arg={}", use_long, arg.name);
if arg.is_hide_set() {
return false;
}
(!arg.is_hide_long_help_set() && use_long)
|| (!arg.is_hide_short_help_set() && !use_long)
|| arg.is_next_line_help_set()
}
fn should_show_subcommand(subcommand: &Command) -> bool {
!subcommand.is_hide_set()
}
fn text_wrapper(help: &str, width: usize) -> String {
let wrapper = textwrap::Options::new(width)
.break_words(false)
.word_splitter(textwrap::WordSplitter::NoHyphenation);
help.lines()
.map(|line| textwrap::fill(line, &wrapper))
.collect::<Vec<String>>()
.join("\n")
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn wrap_help_last_word() {
let help = String::from("foo bar baz");
assert_eq!(text_wrapper(&help, 5), "foo\nbar\nbaz");
}
#[test]
fn display_width_handles_non_ascii() {
// Popular Danish tongue-twister, the name of a fruit dessert.
let text = "rødgrød med fløde";
assert_eq!(display_width(text), 17);
// Note that the string width is smaller than the string
// length. This is due to the precomposed non-ASCII letters:
assert_eq!(text.len(), 20);
}
#[test]
fn display_width_handles_emojis() {
let text = "😂";
// There is a single `char`...
assert_eq!(text.chars().count(), 1);
// but it is double-width:
assert_eq!(display_width(text), 2);
// This is much less than the byte length:
assert_eq!(text.len(), 4);
}
}