fmtview 0.2.0

Fast terminal formatter and viewer for JSON, JSONL, XML-compatible markup, and formatted diffs
Documentation 
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
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130

use std::{
    fs,
    io::Write,
    process::{Command, Stdio},
};

use anyhow::{Context, Result, bail};
use tempfile::NamedTempFile;

use crate::{
    format::{self, FormatOptions},
    input::InputSource,
};

mod model;

pub(crate) use model::{
    DiffChange, DiffIntensity, DiffLayout, DiffModel, DiffRange, NumberedDiffLine, SideDiffRow,
    UnifiedDiffRow,
};

pub fn diff_sources(
    left: &InputSource,
    right: &InputSource,
    options: &FormatOptions,
    show_equal_message: bool,
) -> Result<NamedTempFile> {
    let formatted = format_diff_inputs(left, right, options)?;

    let mut output = NamedTempFile::new().context("failed to create diff temp file")?;
    run_external_diff(
        left,
        right,
        &formatted.left,
        &formatted.right,
        &mut output,
        show_equal_message,
    )?;
    output.flush().context("failed to flush diff temp file")?;
    Ok(output)
}

pub(crate) fn diff_view(
    left: &InputSource,
    right: &InputSource,
    options: &FormatOptions,
) -> Result<DiffModel> {
    let formatted = format_diff_inputs(left, right, options)?;
    let mut output = NamedTempFile::new().context("failed to create diff temp file")?;
    run_external_diff(
        left,
        right,
        &formatted.left,
        &formatted.right,
        &mut output,
        false,
    )?;
    output.flush().context("failed to flush diff temp file")?;
    let patch = fs::read_to_string(output.path()).context("failed to read diff output")?;
    Ok(DiffModel::from_unified_patch(
        left.label().to_owned(),
        right.label().to_owned(),
        &patch,
    ))
}

struct FormattedDiffInputs {
    left: NamedTempFile,
    right: NamedTempFile,
}

fn format_diff_inputs(
    left: &InputSource,
    right: &InputSource,
    options: &FormatOptions,
) -> Result<FormattedDiffInputs> {
    let left_formatted = format::format_source_to_temp(left, options)
        .with_context(|| format!("failed to format left input {}", left.label()))?;
    let right_formatted = format::format_source_to_temp(right, options)
        .with_context(|| format!("failed to format right input {}", right.label()))?;
    Ok(FormattedDiffInputs {
        left: left_formatted,
        right: right_formatted,
    })
}

fn run_external_diff(
    left: &InputSource,
    right: &InputSource,
    left_formatted: &NamedTempFile,
    right_formatted: &NamedTempFile,
    output: &mut NamedTempFile,
    show_equal_message: bool,
) -> Result<()> {
    let mut child = Command::new("diff")
        .arg("-u")
        .arg("--label")
        .arg(left.label())
        .arg("--label")
        .arg(right.label())
        .arg(left_formatted.path())
        .arg(right_formatted.path())
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .spawn()
        .context("failed to start diff")?;

    let mut stdout = child
        .stdout
        .take()
        .context("failed to capture diff stdout")?;
    std::io::copy(&mut stdout, output).context("failed to copy diff output")?;

    let result = child
        .wait_with_output()
        .context("failed to wait for diff")?;
    match result.status.code() {
        Some(0) => {
            if show_equal_message {
                writeln!(output, "No differences").context("failed to write empty diff message")?;
            }
            Ok(())
        }
        Some(1) => Ok(()),
        _ => {
            let stderr = String::from_utf8_lossy(&result.stderr);
            bail!("diff exited with {}: {}", result.status, stderr.trim())
        }
    }
}