dsv 0.13.0

dsv (Data Swiss Knife) — a high-performance CSV, Parquet, and JSONL CLI toolkit. Modern xsv fork with all 33 community PRs merged.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104

use csv;

use crate::config::{Config, Delimiter};
use crate::util;
use crate::CliResult;
use clap::Parser;

#[derive(Parser, Debug)]
pub struct Args {
    #[arg()]
    pub mode: String,
    #[arg()]
    pub arg_input: Vec<String>,
    #[arg(short = 'p', long = "pad")]
    pub flag_pad: bool,
    #[arg(short = 'o', long = "output", value_name = "file")]
    pub flag_output: Option<String>,
    #[arg(short = 'n', long = "no-headers")]
    pub flag_no_headers: bool,
    #[arg(short = 'd', long = "delimiter", value_name = "arg")]
    pub flag_delimiter: Option<Delimiter>,
}

pub fn run(args: &Args) -> CliResult<()> {
    match args.mode.as_str() {
        "rows" => args.cat_rows(),
        "columns" => args.cat_columns(),
        _ => Err(crate::CliError::Other(format!(
            "Unknown cat mode '{}'. Use 'rows' or 'columns'.",
            args.mode
        ))),
    }
}

impl Args {
    fn configs(&self) -> CliResult<Vec<Config>> {
        util::many_configs(&self.arg_input, self.flag_delimiter, self.flag_no_headers)
            .map_err(From::from)
    }

    fn cat_rows(&self) -> CliResult<()> {
        let mut row = csv::ByteRecord::new();
        let mut wtr = Config::new(&self.flag_output).writer()?;
        for (i, conf) in self.configs()?.into_iter().enumerate() {
            let mut rdr = conf.reader()?;
            if i == 0 {
                conf.write_headers(&mut rdr, &mut wtr)?;
            }
            while rdr.read_byte_record(&mut row)? {
                wtr.write_byte_record(&row)?;
            }
        }
        wtr.flush().map_err(From::from)
    }

    fn cat_columns(&self) -> CliResult<()> {
        let mut wtr = Config::new(&self.flag_output).writer()?;
        let mut rdrs = self
            .configs()?
            .into_iter()
            .map(|conf| conf.no_headers(true).reader())
            .collect::<Result<Vec<_>, _>>()?;

        // Find the lengths of each record. If a length varies, then an error
        // will occur so we can rely on the first length being the correct one.
        let mut lengths = vec![];
        for rdr in &mut rdrs {
            lengths.push(rdr.byte_headers()?.len());
        }

        let mut iters = rdrs
            .iter_mut()
            .map(|rdr| rdr.byte_records())
            .collect::<Vec<_>>();
        'OUTER: loop {
            let mut record = csv::ByteRecord::new();
            let mut num_done = 0;
            for (iter, &len) in iters.iter_mut().zip(lengths.iter()) {
                match iter.next() {
                    None => {
                        num_done += 1;
                        if self.flag_pad {
                            for _ in 0..len {
                                record.push_field(b"");
                            }
                        } else {
                            break 'OUTER;
                        }
                    }
                    Some(Err(err)) => return fail!(err),
                    Some(Ok(next)) => record.extend(&next),
                }
            }
            // Only needed when `--pad` is set.
            // When not set, the OUTER loop breaks when the shortest iterator
            // is exhausted.
            if num_done >= iters.len() {
                break 'OUTER;
            }
            wtr.write_byte_record(&record)?;
        }
        wtr.flush().map_err(From::from)
    }
}