forked from bonsai/harakit
fop(1): adds more comments
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c7c6ca2c60
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39
src/fop.rs
39
src/fop.rs
@ -32,8 +32,8 @@ use sysexits::{ EX_DATAERR, EX_IOERR, EX_UNAVAILABLE, EX_USAGE };
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fn main() {
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fn main() {
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let argv = args().collect::<Vec<String>>();
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let argv = args().collect::<Vec<String>>();
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let mut d = '\u{1E}'.to_string();
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let mut d = '\u{1E}'.to_string(); /* ASCII record separator */
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let mut index_arg = 0;
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let mut optind = 0;
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let usage = format!(
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let usage = format!(
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"Usage: {} [-d delimiter] index command [args...]",
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"Usage: {} [-d delimiter] index command [args...]",
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@ -43,10 +43,9 @@ fn main() {
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while let Some(opt) = argv.getopt("d:") {
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while let Some(opt) = argv.getopt("d:") {
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match opt.opt() {
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match opt.opt() {
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Ok(_) => {
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Ok(_) => {
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/* unwrap because Err(OptError::MissingArg) will be returned if
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/* delimiter */
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* opt.arg() is None */
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d = opt.arg().unwrap();
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d = opt.arg().unwrap();
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index_arg = opt.ind();
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optind = opt.ind();
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},
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},
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Err(_) => {
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Err(_) => {
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eprintln!("{}", usage);
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eprintln!("{}", usage);
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@ -55,38 +54,46 @@ fn main() {
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};
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};
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}
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}
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let command_arg = index_arg as usize + 1;
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/* index of the argv[0] for the operator command */
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let command_arg = optind as usize + 1;
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argv.get(command_arg).unwrap_or_else(|| {
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/* argv[0] of the operator command */
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let operator = argv.get(command_arg).unwrap_or_else(|| {
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eprintln!("{}", usage);
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eprintln!("{}", usage);
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exit(EX_USAGE);
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exit(EX_USAGE);
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});
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});
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let index = argv[index_arg].parse::<usize>().unwrap_or_else(|e| {
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/* parse the specified index as a number we can use */
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let index = argv[optind].parse::<usize>().unwrap_or_else(|e| {
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eprintln!("{}: {}: {}", argv[0], argv[1], e);
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eprintln!("{}: {}: {}", argv[0], argv[1], e);
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exit(EX_DATAERR);
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exit(EX_DATAERR);
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});
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});
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let mut buf = String::new();
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let mut buf = String::new();
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let _ = stdin().read_to_string(&mut buf);
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let _ = stdin().read_to_string(&mut buf);
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/* split the buffer by the delimiter (by default, '\u{1E}') */
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let mut fields = buf.split(&d).collect::<Vec<&str>>();
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let mut fields = buf.split(&d).collect::<Vec<&str>>();
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/* collect arguments for the operator command */
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let opts = argv
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let opts = argv
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.iter()
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.iter()
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.clone()
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.clone()
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.skip(command_arg + 1)
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.skip(command_arg + 1) /* skip the command name */
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.collect::<Vec<&String>>();
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.collect::<Vec<&String>>();
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let mut spawned = Command::new(argv.get(command_arg).unwrap())
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/* spawn the command to operate on the field */
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.args(opts)
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let mut spawned = Command::new(operator)
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.args(opts) /* spawn with the specified arguments */
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.stdin(Stdio::piped())
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.stdin(Stdio::piped())
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.stdout(Stdio::piped())
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.stdout(Stdio::piped()) /* piped stdout to handle output ourselves */
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.spawn()
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.spawn()
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.unwrap_or_else( |e| {
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.unwrap_or_else( |e| {
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eprintln!("{}: {}: {}", argv[0], argv[command_arg], e.strerror());
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eprintln!("{}: {}: {}", argv[0], argv[command_arg], e.strerror());
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exit(EX_UNAVAILABLE);
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exit(EX_UNAVAILABLE);
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});
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});
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/* get field we want to pipe into spawned program */
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let field = fields.get(index).unwrap_or_else(|| {
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let field = fields.get(index).unwrap_or_else(|| {
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eprintln!(
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eprintln!(
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"{}: {}: No such index in input",
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"{}: {}: No such index in input",
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@ -96,9 +103,10 @@ fn main() {
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exit(EX_DATAERR);
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exit(EX_DATAERR);
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});
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});
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/* get the stdin of the newly spawned program and feed it the field val */
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if let Some(mut child_stdin) = spawned.stdin.take() {
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if let Some(mut child_stdin) = spawned.stdin.take() {
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let _ = child_stdin.write_all(field.as_bytes());
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let _ = child_stdin.write_all(field.as_bytes());
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drop(child_stdin);
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drop(child_stdin); /* stay safe! drop your children! */
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}
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}
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let output = spawned.wait_with_output().unwrap_or_else(|e| {
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let output = spawned.wait_with_output().unwrap_or_else(|e| {
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@ -106,17 +114,22 @@ fn main() {
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exit(EX_IOERR);
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exit(EX_IOERR);
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});
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});
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/* get the output with which the original field will be replaced */
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let mut replace = output.stdout.clone();
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let mut replace = output.stdout.clone();
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/* as long as it’s not a newline, set the replacement to the output */
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if replace.pop() != Some(b'\n') { replace = output.stdout; }
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if replace.pop() != Some(b'\n') { replace = output.stdout; }
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/* convert the output of the program to UTF-8 */
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let new_field = String::from_utf8(replace).unwrap_or_else(|e| {
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let new_field = String::from_utf8(replace).unwrap_or_else(|e| {
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eprintln!("{}: {}: {}", argv[0], argv[command_arg], e);
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eprintln!("{}: {}: {}", argv[0], argv[command_arg], e);
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exit(EX_IOERR);
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exit(EX_IOERR);
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});
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});
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/* store the new field in the old fields vector */
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fields[index] = &new_field;
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fields[index] = &new_field;
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/* fop it */
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stdout().write_all(
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stdout().write_all(
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fields.join(&d.to_string()).as_bytes()
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fields.join(&d.to_string()).as_bytes()
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).unwrap_or_else(|e| {
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).unwrap_or_else(|e| {
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