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
247
248
249
250
251
252
253
254
255
256
257
258
259
260
// Copyright 2019-2021 Parity Technologies (UK) Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use crate::prelude::{
    fmt::{
        Display,
        Error as FmtError,
        Formatter,
    },
    vec,
    vec::Vec,
};

use crate::{
    form::{
        Form,
        MetaForm,
        PortableForm,
    },
    utils::is_rust_identifier,
    IntoPortable,
    Registry,
};
use scale::{
    Decode,
    Encode,
};
#[cfg(feature = "serde")]
use serde::{
    de::DeserializeOwned,
    Deserialize,
    Serialize,
};

/// Represents the path of a type definition.
///
/// This consists of several segments that each have to be a valid Rust
/// identifier. The first segment represents the crate name in which the type
/// has been defined. The last
///
/// Rust prelude type may have an empty namespace definition.
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Encode, Decode)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[cfg_attr(
    feature = "serde",
    serde(bound(
        serialize = "T::Type: Serialize, T::String: Serialize",
        deserialize = "T::Type: DeserializeOwned, T::String: DeserializeOwned",
    ))
)]
#[cfg_attr(feature = "serde", serde(transparent))]
pub struct Path<T: Form = MetaForm> {
    /// The segments of the namespace.
    segments: Vec<T::String>,
}

impl<T> Default for Path<T>
where
    T: Form,
{
    fn default() -> Self {
        Path {
            segments: Vec::new(),
        }
    }
}

impl IntoPortable for Path {
    type Output = Path<PortableForm>;

    fn into_portable(self, registry: &mut Registry) -> Self::Output {
        Path {
            segments: registry.map_into_portable(self.segments),
        }
    }
}

impl Display for Path<PortableForm> {
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), FmtError> {
        write!(f, "{}", self.segments.join("::"))
    }
}

impl Path {
    /// Create a new Path
    ///
    /// # Panics
    ///
    /// - If the type identifier or module path contain invalid Rust identifiers
    pub fn new(ident: &'static str, module_path: &'static str) -> Path {
        let mut segments = module_path.split("::").collect::<Vec<_>>();
        segments.push(ident);
        Self::from_segments(segments)
            .expect("All path segments should be valid Rust identifiers")
    }

    /// Create an empty path for types which shall not be named
    #[allow(unused)]
    pub(crate) fn voldemort() -> Path {
        Path {
            segments: Vec::new(),
        }
    }

    /// Crate a Path for types in the Prelude namespace
    ///
    /// # Panics
    ///
    /// - If the supplied ident is not a valid Rust identifier
    pub(crate) fn prelude(ident: &'static str) -> Path {
        Self::from_segments(vec![ident])
            .unwrap_or_else(|_| panic!("{} is not a valid Rust identifier", ident))
    }

    /// Create a Path from the given segments
    ///
    /// # Errors
    ///
    /// - If no segments are supplied
    /// - If any of the segments are invalid Rust identifiers
    pub fn from_segments<I>(segments: I) -> Result<Path, PathError>
    where
        I: IntoIterator<Item = &'static str>,
    {
        let segments = segments.into_iter().collect::<Vec<_>>();
        if segments.is_empty() {
            return Err(PathError::MissingSegments)
        }
        if let Some(err_at) = segments.iter().position(|seg| !is_rust_identifier(seg)) {
            return Err(PathError::InvalidIdentifier { segment: err_at })
        }
        Ok(Path { segments })
    }
}

impl<T> Path<T>
where
    T: Form,
{
    /// Returns the segments of the Path
    pub fn segments(&self) -> &[T::String] {
        &self.segments
    }

    /// Returns `true` if the path is empty
    pub fn is_empty(&self) -> bool {
        self.segments.is_empty()
    }

    /// Get the ident segment of the Path
    pub fn ident(&self) -> Option<T::String> {
        self.segments.iter().last().cloned()
    }

    /// Get the namespace segments of the Path
    pub fn namespace(&self) -> &[T::String] {
        self.segments.split_last().map(|(_, ns)| ns).unwrap_or(&[])
    }
}

/// An error that may be encountered upon constructing namespaces.
#[derive(PartialEq, Eq, Debug)]
pub enum PathError {
    /// If the module path does not at least have one segment.
    MissingSegments,
    /// If a segment within a module path is not a proper Rust identifier.
    InvalidIdentifier {
        /// The index of the erroneous segment.
        segment: usize,
    },
}

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

    #[test]
    fn path_ok() {
        assert_eq!(
            Path::from_segments(vec!["hello"]),
            Ok(Path {
                segments: vec!["hello"]
            })
        );
        assert_eq!(
            Path::from_segments(vec!["Hello", "World"]),
            Ok(Path {
                segments: vec!["Hello", "World"]
            })
        );
        assert_eq!(
            Path::from_segments(vec!["_"]),
            Ok(Path {
                segments: vec!["_"]
            })
        );
    }

    #[test]
    fn path_err() {
        assert_eq!(Path::from_segments(vec![]), Err(PathError::MissingSegments));
        assert_eq!(
            Path::from_segments(vec![""]),
            Err(PathError::InvalidIdentifier { segment: 0 })
        );
        assert_eq!(
            Path::from_segments(vec!["1"]),
            Err(PathError::InvalidIdentifier { segment: 0 })
        );
        assert_eq!(
            Path::from_segments(vec!["Hello", ", World!"]),
            Err(PathError::InvalidIdentifier { segment: 1 })
        );
    }

    #[test]
    fn path_from_module_path_and_ident() {
        assert_eq!(
            Path::new("Planet", "hello::world"),
            Path {
                segments: vec!["hello", "world", "Planet"]
            }
        );
        assert_eq!(
            Path::from_segments(vec!["Earth", "::world"]),
            Err(PathError::InvalidIdentifier { segment: 1 })
        );
    }

    #[test]
    fn path_get_namespace_and_ident() {
        let path = Path::new("Planet", "hello::world");
        assert_eq!(path.namespace(), &["hello", "world"]);
        assert_eq!(path.ident(), Some("Planet"));
    }

    #[test]
    #[should_panic]
    fn path_new_panics_with_invalid_identifiers() {
        Path::new("Planet", "hello$!@$::world");
    }

    #[test]
    fn path_display() {
        let path =
            Path::new("Planet", "hello::world").into_portable(&mut Default::default());
        assert_eq!("hello::world::Planet", format!("{}", path))
    }
}