bat/tests/syntax-tests/highlighted/Rust/output.rs
2020-08-03 15:59:53 +02:00

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use std::io::{self, Write};
#[cfg(feature = "paging")]
use std::process::Child;
use crate::error::*;
#[cfg(feature = "paging")]
use crate::less::retrieve_less_version;
#[cfg(feature = "paging")]
use crate::paging::PagingMode;
#[derive(Debug)]
pub enum OutputType {
 #[cfg(feature = "paging")]
 Pager(Child),
 Stdout(io::Stdout),
}
impl OutputType {
 #[cfg(feature = "paging")]
 pub fn from_mode(mode: PagingMode, pager: Option<&str>) -> Result<Self> {
 use self::PagingMode::*;
 Ok(match mode {
 Always => OutputType::try_pager(false, pager)?,
 QuitIfOneScreen => OutputType::try_pager(true, pager)?,
 _ => OutputType::stdout(),
 })
 }
 /// Try to launch the pager. Fall back to stdout in case of errors.
 #[cfg(feature = "paging")]
 fn try_pager(quit_if_one_screen: bool, pager_from_config: Option<&str>) -> Result<Self> {
 use std::env;
 use std::ffi::OsString;
 use std::path::PathBuf;
 use std::process::{Command, Stdio};
 let mut replace_arguments_to_less = false;
 let pager_from_env = match (env::var("BAT_PAGER"), env::var("PAGER")) {
 (Ok(bat_pager), _) => Some(bat_pager),
 (_, Ok(pager)) => {
 // less needs to be called with the '-R' option in order to properly interpret the
 // ANSI color sequences printed by bat. If someone has set PAGER="less -F", we
 // therefore need to overwrite the arguments and add '-R'.
 //
 // We only do this for PAGER (as it is not specific to 'bat'), not for BAT_PAGER
 // or bats '--pager' command line option.
 replace_arguments_to_less = true;
 Some(pager)
 }
 _ => None,
 };
 let pager_from_config = pager_from_config.map(|p| p.to_string());
 if pager_from_config.is_some() {
 replace_arguments_to_less = false;
 }
 let pager = pager_from_config
 .or(pager_from_env)
 .unwrap_or_else(|| String::from("less"));
 let pagerflags =
 shell_words::split(&pager).chain_err(|| "Could not parse pager command.")?;
 match pagerflags.split_first() {
 Some((pager_name, args)) => {
 let mut pager_path = PathBuf::from(pager_name);
 if pager_path.file_stem() == Some(&OsString::from("bat")) {
 pager_path = PathBuf::from("less");
 }
 let is_less = pager_path.file_stem() == Some(&OsString::from("less"));
 let mut process = if is_less {
 let mut p = Command::new(&pager_path);
 if args.is_empty() || replace_arguments_to_less {
 p.arg("--RAW-CONTROL-CHARS");
 if quit_if_one_screen {
 p.arg("--quit-if-one-screen");
 }
 // Passing '--no-init' fixes a bug with '--quit-if-one-screen' in older
 // versions of 'less'. Unfortunately, it also breaks mouse-wheel support.
 //
 // See: http://www.greenwoodsoftware.com/less/news.530.html
 //
 // For newer versions (530 or 558 on Windows), we omit '--no-init' as it
 // is not needed anymore.
 match retrieve_less_version() {
 None => {
 p.arg("--no-init");
 }
 Some(version)
 if (version < 530 || (cfg!(windows) && version < 558)) =>
 {
 p.arg("--no-init");
 }
 _ => {}
 }
 } else {
 p.args(args);
 }
 p.env("LESSCHARSET", "UTF-8");
 p
 } else {
 let mut p = Command::new(&pager_path);
 p.args(args);
 p
 };
 Ok(process
 .stdin(Stdio::piped())
 .spawn()
 .map(OutputType::Pager)
 .unwrap_or_else(|_| OutputType::stdout()))
 }
 None => Ok(OutputType::stdout()),
 }
 }
 pub(crate) fn stdout() -> Self {
 OutputType::Stdout(io::stdout())
 }
 #[cfg(feature = "paging")]
 pub(crate) fn is_pager(&self) -> bool {
 if let OutputType::Pager(_) = self {
 true
 } else {
 false
 }
 }
 #[cfg(not(feature = "paging"))]
 pub(crate) fn is_pager(&self) -> bool {
 false
 }
 pub fn handle(&mut self) -> Result<&mut dyn Write> {
 Ok(match *self {
 #[cfg(feature = "paging")]
 OutputType::Pager(ref mut command) => command
 .stdin
 .as_mut()
 .chain_err(|| "Could not open stdin for pager")?,
 OutputType::Stdout(ref mut handle) => handle,
 })
 }
}
#[cfg(feature = "paging")]
impl Drop for OutputType {
 fn drop(&mut self) {
 if let OutputType::Pager(ref mut command) = *self {
 let _ = command.wait();
 }
 }
}