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| 1 | +use crate::aliased_command; |
| 2 | +use cargo::util::errors::CargoResult; |
| 3 | +use cargo::util::paths::resolve_executable; |
| 4 | +use cargo::Config; |
| 5 | +use flate2::read::GzDecoder; |
| 6 | +use std::ffi::OsString; |
| 7 | +use std::io::Read; |
| 8 | +use std::io::Write; |
| 9 | +use std::path::Path; |
| 10 | + |
| 11 | +const COMPRESSED_MAN: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/man.tgz")); |
| 12 | + |
| 13 | +/// Checks if the `help` command is being issued. |
| 14 | +/// |
| 15 | +/// This runs before clap processing, because it needs to intercept the `help` |
| 16 | +/// command if a man page is available. |
| 17 | +/// |
| 18 | +/// Returns `true` if a man page was displayed. In this case, Cargo should |
| 19 | +/// exit. |
| 20 | +pub fn handle_embedded_help(config: &Config) -> bool { |
| 21 | + match try_help(config) { |
| 22 | + Ok(true) => true, |
| 23 | + Ok(false) => false, |
| 24 | + Err(e) => { |
| 25 | + log::warn!("man failed: {:?}", e); |
| 26 | + false |
| 27 | + } |
| 28 | + } |
| 29 | +} |
| 30 | + |
| 31 | +fn try_help(config: &Config) -> CargoResult<bool> { |
| 32 | + let mut args = std::env::args_os() |
| 33 | + .skip(1) |
| 34 | + .skip_while(|arg| arg.to_str().map_or(false, |s| s.starts_with('-'))); |
| 35 | + if !args |
| 36 | + .next() |
| 37 | + .map_or(false, |arg| arg.to_str() == Some("help")) |
| 38 | + { |
| 39 | + return Ok(false); |
| 40 | + } |
| 41 | + let subcommand = match args.next() { |
| 42 | + Some(arg) => arg, |
| 43 | + None => return Ok(false), |
| 44 | + }; |
| 45 | + let subcommand = match subcommand.to_str() { |
| 46 | + Some(s) => s, |
| 47 | + None => return Ok(false), |
| 48 | + }; |
| 49 | + // Check if this is a built-in command (or alias); |
| 50 | + let subcommand = match check_alias(config, subcommand) { |
| 51 | + Some(s) => s, |
| 52 | + None => return Ok(false), |
| 53 | + }; |
| 54 | + if resolve_executable(Path::new("man")).is_ok() { |
| 55 | + let man = match extract_man(&subcommand, "1") { |
| 56 | + Some(man) => man, |
| 57 | + None => return Ok(false), |
| 58 | + }; |
| 59 | + write_and_spawn(&man, "man")?; |
| 60 | + } else { |
| 61 | + let txt = match extract_man(&subcommand, "txt") { |
| 62 | + Some(txt) => txt, |
| 63 | + None => return Ok(false), |
| 64 | + }; |
| 65 | + if resolve_executable(Path::new("less")).is_ok() { |
| 66 | + write_and_spawn(&txt, "less")?; |
| 67 | + } else if resolve_executable(Path::new("more")).is_ok() { |
| 68 | + write_and_spawn(&txt, "more")?; |
| 69 | + } else { |
| 70 | + drop(std::io::stdout().write_all(&txt)); |
| 71 | + } |
| 72 | + } |
| 73 | + Ok(true) |
| 74 | +} |
| 75 | + |
| 76 | +/// Checks if the given subcommand is a built-in command (possibly via an alias). |
| 77 | +/// |
| 78 | +/// Returns None if it is not a built-in command. |
| 79 | +fn check_alias(config: &Config, subcommand: &str) -> Option<String> { |
| 80 | + if super::builtin_exec(subcommand).is_some() { |
| 81 | + return Some(subcommand.to_string()); |
| 82 | + } |
| 83 | + match aliased_command(config, subcommand) { |
| 84 | + Ok(Some(alias)) => { |
| 85 | + let alias = alias.into_iter().next()?; |
| 86 | + if super::builtin_exec(&alias).is_some() { |
| 87 | + Some(alias) |
| 88 | + } else { |
| 89 | + None |
| 90 | + } |
| 91 | + } |
| 92 | + _ => None, |
| 93 | + } |
| 94 | +} |
| 95 | + |
| 96 | +/// Extracts the given man page from the compressed archive. |
| 97 | +/// |
| 98 | +/// Returns None if the command wasn't found. |
| 99 | +fn extract_man(subcommand: &str, extension: &str) -> Option<Vec<u8>> { |
| 100 | + let extract_name = OsString::from(format!("cargo-{}.{}", subcommand, extension)); |
| 101 | + let gz = GzDecoder::new(COMPRESSED_MAN); |
| 102 | + let mut ar = tar::Archive::new(gz); |
| 103 | + // Unwraps should be safe here, since this is a static archive generated |
| 104 | + // by our build script. It should never be an invalid format! |
| 105 | + for entry in ar.entries().unwrap() { |
| 106 | + let mut entry = entry.unwrap(); |
| 107 | + let path = entry.path().unwrap(); |
| 108 | + if path.file_name().unwrap() != extract_name { |
| 109 | + continue; |
| 110 | + } |
| 111 | + let mut result = Vec::new(); |
| 112 | + entry.read_to_end(&mut result).unwrap(); |
| 113 | + return Some(result); |
| 114 | + } |
| 115 | + None |
| 116 | +} |
| 117 | + |
| 118 | +/// Write the contents of a man page to disk and spawn the given command to |
| 119 | +/// display it. |
| 120 | +fn write_and_spawn(contents: &[u8], command: &str) -> CargoResult<()> { |
| 121 | + let mut tmp = tempfile::Builder::new().prefix("cargo-man").tempfile()?; |
| 122 | + let f = tmp.as_file_mut(); |
| 123 | + f.write_all(&contents)?; |
| 124 | + f.flush()?; |
| 125 | + let mut cmd = std::process::Command::new(command) |
| 126 | + .arg(tmp.path()) |
| 127 | + .spawn()?; |
| 128 | + drop(cmd.wait()); |
| 129 | + Ok(()) |
| 130 | +} |
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