tinytemplate/
error.rs

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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
//! Module containing the error type returned by TinyTemplate if an error occurs.

use instruction::{path_to_str, PathSlice};
use serde_json::Error as SerdeJsonError;
use serde_json::Value;
use std::error::Error as StdError;
use std::fmt;

/// Enum representing the potential errors that TinyTemplate can encounter.
#[derive(Debug)]
pub enum Error {
    ParseError {
        msg: String,
        line: usize,
        column: usize,
    },
    RenderError {
        msg: String,
        line: usize,
        column: usize,
    },
    SerdeError {
        err: SerdeJsonError,
    },
    GenericError {
        msg: String,
    },
    StdFormatError {
        err: fmt::Error,
    },
    CalledTemplateError {
        name: String,
        err: Box<Error>,
        line: usize,
        column: usize,
    },
    CalledFormatterError {
        name: String,
        err: Box<Error>,
        line: usize,
        column: usize,
    },

    #[doc(hidden)]
    __NonExhaustive,
}
impl From<SerdeJsonError> for Error {
    fn from(err: SerdeJsonError) -> Error {
        Error::SerdeError { err }
    }
}
impl From<fmt::Error> for Error {
    fn from(err: fmt::Error) -> Error {
        Error::StdFormatError { err }
    }
}
impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            Error::ParseError { msg, line, column } => write!(
                f,
                "Failed to parse the template (line {}, column {}). Reason: {}",
                line, column, msg
            ),
            Error::RenderError { msg, line, column } => {
                write!(
                    f,
                    "Encountered rendering error on line {}, column {}. Reason: {}",
                    line, column, msg
                )
            }
            Error::SerdeError { err } => {
                write!(f, "Unexpected serde error while converting the context to a serde_json::Value. Error: {}", err)
            }
            Error::GenericError { msg } => {
                write!(f, "{}", msg)
            }
            Error::StdFormatError { err } => {
                write!(f, "Unexpected formatting error: {}", err)
            }
            Error::CalledTemplateError {
                name,
                err,
                line,
                column,
            } => {
                write!(
                    f,
                    "Call to sub-template \"{}\" on line {}, column {} failed. Reason: {}",
                    name, line, column, err
                )
            }
            Error::CalledFormatterError {
                name,
                err,
                line,
                column,
            } => {
                write!(
                    f,
                    "Call to value formatter \"{}\" on line {}, column {} failed. Reason: {}",
                    name, line, column, err
                )
            }
            Error::__NonExhaustive => unreachable!(),
        }
    }
}
impl StdError for Error {
    fn description(&self) -> &str {
        match self {
            Error::ParseError { .. } => "ParseError",
            Error::RenderError { .. } => "RenderError",
            Error::SerdeError { .. } => "SerdeError",
            Error::GenericError { msg } => &msg,
            Error::StdFormatError { .. } => "StdFormatError",
            Error::CalledTemplateError { .. } => "CalledTemplateError",
            Error::CalledFormatterError { .. } => "CalledFormatterError",
            Error::__NonExhaustive => unreachable!(),
        }
    }
}

pub type Result<T> = ::std::result::Result<T, Error>;

pub(crate) fn lookup_error(source: &str, step: &str, path: PathSlice, current: &Value) -> Error {
    let avail_str = if let Value::Object(object_map) = current {
        let mut avail_str = " Available values at this level are ".to_string();
        for (i, key) in object_map.keys().enumerate() {
            if i > 0 {
                avail_str.push_str(", ");
            }
            avail_str.push('\'');
            avail_str.push_str(key);
            avail_str.push('\'');
        }
        avail_str
    } else {
        "".to_string()
    };

    let (line, column) = get_offset(source, step);

    Error::RenderError {
        msg: format!(
            "Failed to find value '{}' from path '{}'.{}",
            step,
            path_to_str(path),
            avail_str
        ),
        line,
        column,
    }
}

pub(crate) fn truthiness_error(source: &str, path: PathSlice) -> Error {
    let (line, column) = get_offset(source, path.last().unwrap());
    Error::RenderError {
        msg: format!(
            "Path '{}' produced a value which could not be checked for truthiness.",
            path_to_str(path)
        ),
        line,
        column,
    }
}

pub(crate) fn unprintable_error() -> Error {
    Error::GenericError {
        msg: "Expected a printable value but found array or object.".to_string(),
    }
}

pub(crate) fn not_iterable_error(source: &str, path: PathSlice) -> Error {
    let (line, column) = get_offset(source, path.last().unwrap());
    Error::RenderError {
        msg: format!(
            "Expected an array for path '{}' but found a non-iterable value.",
            path_to_str(path)
        ),
        line,
        column,
    }
}

pub(crate) fn unknown_template(source: &str, name: &str) -> Error {
    let (line, column) = get_offset(source, name);
    Error::RenderError {
        msg: format!("Tried to call an unknown template '{}'", name),
        line,
        column,
    }
}

pub(crate) fn unknown_formatter(source: &str, name: &str) -> Error {
    let (line, column) = get_offset(source, name);
    Error::RenderError {
        msg: format!("Tried to call an unknown formatter '{}'", name),
        line,
        column,
    }
}

pub(crate) fn called_template_error(source: &str, template_name: &str, err: Error) -> Error {
    let (line, column) = get_offset(source, template_name);
    Error::CalledTemplateError {
        name: template_name.to_string(),
        err: Box::new(err),
        line,
        column,
    }
}

pub(crate) fn called_formatter_error(source: &str, formatter_name: &str, err: Error) -> Error {
    let (line, column) = get_offset(source, formatter_name);
    Error::CalledFormatterError {
        name: formatter_name.to_string(),
        err: Box::new(err),
        line,
        column,
    }
}

/// Find the line number and column of the target string within the source string. Will panic if
/// target is not a substring of source.
pub(crate) fn get_offset(source: &str, target: &str) -> (usize, usize) {
    let offset = target.as_ptr() as isize - source.as_ptr() as isize;
    let to_scan = &source[0..(offset as usize)];

    let mut line = 1;
    let mut column = 0;

    for byte in to_scan.bytes() {
        match byte as char {
            '\n' => {
                line += 1;
                column = 0;
            }
            _ => {
                column += 1;
            }
        }
    }

    (line, column)
}