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66 lines
1.8 KiB
66 lines
1.8 KiB
use std::{fmt,error};
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/// Print help message then exit with code `2`.
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pub fn usage() -> !
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{
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eprintln!("uasge: {} <output file> <input files...>", std::env::args().next().unwrap());
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eprintln!();
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eprintln!("mapcat v{}: mmap() based file concatenation", env!("CARGO_PKG_VERSION"));
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eprintln!(" by {} with <3 (licensed GPL3+)", env!("CARGO_PKG_AUTHORS"));
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eprintln!();
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eprintln!("NOTES:");
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eprintln!("The output file is required, if one is not provided, we will just print this message and exit with error code `2`. If there are no input files, it will just create an empty output and return with error code `0` (unless there were other errors)");
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eprintln!("Output files are always clobbered regardless if there are any inputs, or if the concatenation operation succeeds / fails");
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eprintln!();
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#[cfg(feature="threads")] eprintln!(" (compiled with write parallelisation enabled)");
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std::process::exit(2)
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}
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
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pub struct Operation
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{
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pub output: String,
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pub inputs: Vec<String>,
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}
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/// Parse the arguments passed to the process
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#[inline] pub fn parse_args() -> Result<Operation, ArgParseError>
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{
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parse(std::env::args().skip(1))
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}
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fn parse<J: Into<String>, I: IntoIterator<Item = J>>(args: I) -> Result<Operation, ArgParseError>
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{
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let mut args = args.into_iter().map(Into::into);
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let output = args.next().ok_or(ArgParseError::NoOutput)?;
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Ok(
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Operation {
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output,
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inputs: args.collect(),
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}
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)
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}
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#[derive(Debug)]
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pub enum ArgParseError
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{
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NoOutput,
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}
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impl error::Error for ArgParseError{}
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impl fmt::Display for ArgParseError
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{
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
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{
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match self {
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Self::NoOutput => write!(f, "output file was not provided"),
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}
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}
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}
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