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
131
use nu_engine::CallExt;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
    Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, Span, Spanned,
    SyntaxShape, Type, Value,
};

#[derive(Clone)]
pub struct Encode;

impl Command for Encode {
    fn name(&self) -> &str {
        "encode"
    }

    fn usage(&self) -> &str {
        // Note: "Encode a UTF-8 string into other forms" is semantically incorrect because
        // Nushell strings, as abstract values, have no user-facing encoding.
        // (Remember that "encoding" exclusively means "how the characters are
        // observably represented by bytes").
        "Encode a string into bytes."
    }

    fn search_terms(&self) -> Vec<&str> {
        vec!["text", "encoding", "decoding"]
    }

    fn signature(&self) -> nu_protocol::Signature {
        Signature::build("encode")
            .input_output_types(vec![(Type::String, Type::Binary)])
            .required("encoding", SyntaxShape::String, "the text encoding to use")
            .switch(
                "ignore-errors",
                "when a character isn't in the given encoding, replace with a HTML entity (like `&#127880;`)",
                Some('i'),
            )
            .category(Category::Strings)
    }

    fn extra_usage(&self) -> &str {
        r#"Multiple encodings are supported; here are a few:
big5, euc-jp, euc-kr, gbk, iso-8859-1, cp1252, latin5

Note that since the Encoding Standard doesn't specify encoders for utf-16le and utf-16be, these are not yet supported.

For a more complete list of encodings, please refer to the encoding_rs
documentation link at https://docs.rs/encoding_rs/latest/encoding_rs/#statics"#
    }

    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "Encode an UTF-8 string into Shift-JIS",
                example: r#""負けると知って戦うのが、遥かに美しいのだ" | encode shift-jis"#,
                result: Some(Value::Binary {
                    val: vec![
                        0x95, 0x89, 0x82, 0xaf, 0x82, 0xe9, 0x82, 0xc6, 0x92, 0x6d, 0x82, 0xc1,
                        0x82, 0xc4, 0x90, 0xed, 0x82, 0xa4, 0x82, 0xcc, 0x82, 0xaa, 0x81, 0x41,
                        0x97, 0x79, 0x82, 0xa9, 0x82, 0xc9, 0x94, 0xfc, 0x82, 0xb5, 0x82, 0xa2,
                        0x82, 0xcc, 0x82, 0xbe,
                    ],
                    span: Span::test_data(),
                }),
            },
            Example {
                description: "Replace characters with HTML entities if they can't be encoded",
                example: r#""🎈" | encode -i shift-jis"#,
                result: Some(Value::Binary {
                    val: vec![0x26, 0x23, 0x31, 0x32, 0x37, 0x38, 0x38, 0x30, 0x3b],
                    span: Span::test_data(),
                }),
            },
        ]
    }

    fn run(
        &self,
        engine_state: &EngineState,
        stack: &mut Stack,
        call: &Call,
        input: PipelineData,
    ) -> Result<PipelineData, ShellError> {
        let head = call.head;
        let encoding: Spanned<String> = call.req(engine_state, stack, 0)?;
        let ignore_errors = call.has_flag("ignore-errors");

        match input {
            PipelineData::ExternalStream { stdout: None, .. } => Ok(PipelineData::empty()),
            PipelineData::ExternalStream {
                stdout: Some(stream),
                ..
            } => {
                let s = stream.into_string()?;
                super::encoding::encode(head, encoding, &s.item, s.span, ignore_errors)
                    .map(|val| val.into_pipeline_data())
            }
            PipelineData::Value(v, ..) => match v {
                Value::String { val: s, span } => {
                    super::encoding::encode(head, encoding, &s, span, ignore_errors)
                        .map(|val| val.into_pipeline_data())
                }
                Value::Error { error } => Err(*error),
                _ => Err(ShellError::OnlySupportsThisInputType {
                    exp_input_type: "string".into(),
                    wrong_type: v.get_type().to_string(),
                    dst_span: head,
                    src_span: v.expect_span(),
                }),
            },
            // This should be more precise, but due to difficulties in getting spans
            // from PipelineData::ListStream, this is as it is.
            _ => Err(ShellError::UnsupportedInput(
                "non-string input".into(),
                "value originates from here".into(),
                head,
                input.span().unwrap_or(head),
            )),
        }
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_examples() {
        crate::test_examples(Encode)
    }
}