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 { 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 { 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(); } } }