apache_avro/schema/
name.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18use serde::{Deserialize, Serialize, Serializer};
19use serde_json::{Map, Value};
20use std::borrow::Cow;
21use std::collections::HashMap;
22use std::fmt::{Debug, Display, Formatter};
23use std::str::FromStr;
24
25use crate::{
26    AvroResult, Error, Schema,
27    error::Details,
28    util::MapHelper,
29    validator::{validate_namespace, validate_schema_name},
30};
31
32/// Represents names for `record`, `enum` and `fixed` Avro schemas.
33///
34/// Each of these `Schema`s have a `fullname` composed of two parts:
35///   * a name
36///   * a namespace
37///
38/// `aliases` can also be defined, to facilitate schema evolution.
39///
40/// More information about schema names can be found in the
41/// [Avro specification](https://avro.apache.org/docs/++version++/specification/#names)
42#[derive(Clone, Hash, PartialEq, Eq)]
43pub struct Name {
44    /// The full name
45    namespace_and_name: String,
46    /// Start byte of the name part
47    ///
48    /// If this is zero, then there is no namespace.
49    index_of_name: usize,
50}
51
52/// Represents the aliases for Named Schema
53pub type Aliases = Option<Vec<Alias>>;
54/// Represents Schema lookup within a schema env
55pub type Names = HashMap<Name, Schema>;
56/// Represents Schema lookup within a schema
57pub type NamesRef<'a> = HashMap<Name, &'a Schema>;
58/// Represents the namespace for Named Schema
59pub type Namespace = Option<String>;
60/// Represents the namespace for Named Schema
61pub type NamespaceRef<'a> = Option<&'a str>;
62
63impl Name {
64    /// Create a new `Name`.
65    /// Parses the optional `namespace` from the `name` string.
66    /// `aliases` will not be defined.
67    pub fn new(name: impl Into<String> + AsRef<str>) -> AvroResult<Self> {
68        Self::new_with_enclosing_namespace(name, None)
69    }
70
71    /// Create a new `Name` using the namespace from `enclosing_namespace` if absent.
72    pub fn new_with_enclosing_namespace(
73        name: impl Into<String> + AsRef<str>,
74        enclosing_namespace: NamespaceRef,
75    ) -> AvroResult<Self> {
76        // Having both `Into<String>` and `AsRef<str>` allows optimal use in both of these cases:
77        // - `name` is a `String`. We can reuse the allocation when `enclosing_namespace` is `None`
78        //   or `name` already has a namespace.
79        // - `name` is a `str`. With only `Into<String` we need an extra allocation in the case `name`
80        //   doesn't have namespace and `enclosing_namespace` is `Some`. Having `AsRef<str>` allows
81        //   skipping that allocation.
82        let name_ref = name.as_ref();
83        let index_of_name = validate_schema_name(name_ref)?;
84        if index_of_name > name_ref.len() {
85            return Err(Details::InvalidSchemaNameValidatorImplementation.into());
86        }
87
88        if index_of_name == 0
89            && let Some(namespace) = enclosing_namespace
90            && !namespace.is_empty()
91        {
92            validate_namespace(namespace)?;
93            Ok(Self {
94                namespace_and_name: format!("{namespace}.{name_ref}"),
95                index_of_name: namespace.len() + 1,
96            })
97        } else if index_of_name == 1 {
98            // Name has a leading dot
99            Ok(Self {
100                namespace_and_name: name.as_ref()[1..].into(),
101                index_of_name: 0,
102            })
103        } else {
104            Ok(Self {
105                namespace_and_name: name.into(),
106                index_of_name,
107            })
108        }
109    }
110
111    /// Parse a `serde_json::Value` into a `Name`.
112    pub(crate) fn parse(
113        complex: &Map<String, Value>,
114        enclosing_namespace: NamespaceRef,
115    ) -> AvroResult<Self> {
116        let name_field = complex.name().ok_or(Details::GetNameField)?;
117        Self::new_with_enclosing_namespace(
118            name_field,
119            complex.string("namespace").or(enclosing_namespace),
120        )
121    }
122
123    pub fn name(&self) -> &str {
124        &self.namespace_and_name[self.index_of_name..]
125    }
126
127    pub fn namespace(&self) -> NamespaceRef<'_> {
128        if self.index_of_name == 0 {
129            None
130        } else {
131            Some(&self.namespace_and_name[..(self.index_of_name - 1)])
132        }
133    }
134
135    /// Return the `fullname` of this `Name`
136    ///
137    /// More information about fullnames can be found in the
138    /// [Avro specification](https://avro.apache.org/docs/++version++/specification/#names)
139    pub fn fullname(&self, enclosing_namespace: NamespaceRef) -> String {
140        if self.index_of_name == 0
141            && let Some(namespace) = enclosing_namespace
142            && !namespace.is_empty()
143        {
144            format!("{namespace}.{}", self.namespace_and_name)
145        } else {
146            self.namespace_and_name.clone()
147        }
148    }
149
150    /// Construct the fully qualified name
151    ///
152    /// ```
153    /// # use apache_avro::{Error, schema::Name};
154    /// assert_eq!(
155    ///     Name::new("some_name")?.fully_qualified_name(Some("some_namespace")).into_owned(),
156    ///     Name::new("some_namespace.some_name")?
157    /// );
158    /// assert_eq!(
159    ///     Name::new("some_namespace.some_name")?.fully_qualified_name(Some("other_namespace")).into_owned(),
160    ///     Name::new("some_namespace.some_name")?
161    /// );
162    /// # Ok::<(), Error>(())
163    /// ```
164    pub fn fully_qualified_name(&self, enclosing_namespace: NamespaceRef) -> Cow<'_, Name> {
165        if self.index_of_name == 0
166            && let Some(namespace) = enclosing_namespace
167            && !namespace.is_empty()
168        {
169            Cow::Owned(Self {
170                namespace_and_name: format!("{namespace}.{}", self.namespace_and_name),
171                index_of_name: namespace.len() + 1,
172            })
173        } else {
174            Cow::Borrowed(self)
175        }
176    }
177
178    /// Create an empty name.
179    ///
180    /// This name is invalid and should never be used anywhere! The only valid use is filling
181    /// a `Name` field that will not be used.
182    ///
183    /// Using this name will cause a panic.
184    pub(crate) fn invalid_empty_name() -> Self {
185        Self {
186            namespace_and_name: String::new(),
187            index_of_name: usize::MAX,
188        }
189    }
190}
191
192impl TryFrom<&str> for Name {
193    type Error = Error;
194
195    fn try_from(value: &str) -> Result<Self, Self::Error> {
196        Self::new(value)
197    }
198}
199
200impl TryFrom<String> for Name {
201    type Error = Error;
202
203    fn try_from(value: String) -> Result<Self, Self::Error> {
204        Self::new(&value)
205    }
206}
207
208impl FromStr for Name {
209    type Err = Error;
210
211    fn from_str(s: &str) -> Result<Self, Self::Err> {
212        Self::new(s)
213    }
214}
215
216impl Debug for Name {
217    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
218        if self.index_of_name > self.namespace_and_name.len() {
219            f.debug_tuple("Name").field(&"Invalid name!").finish()
220        } else {
221            let mut debug = f.debug_struct("Name");
222            debug.field("name", &self.name());
223            if self.index_of_name != 0 {
224                debug.field("namespace", &self.namespace());
225                debug.finish()
226            } else {
227                debug.finish_non_exhaustive()
228            }
229        }
230    }
231}
232
233impl AsRef<str> for Name {
234    fn as_ref(&self) -> &str {
235        self.namespace_and_name.as_ref()
236    }
237}
238
239impl Display for Name {
240    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
241        assert!(
242            self.index_of_name <= self.namespace_and_name.len(),
243            "Invalid name used"
244        );
245        f.write_str(&self.namespace_and_name)
246    }
247}
248
249impl<'de> Deserialize<'de> for Name {
250    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
251    where
252        D: serde::de::Deserializer<'de>,
253    {
254        Value::deserialize(deserializer).and_then(|value| {
255            use serde::de::Error;
256            if let Value::Object(json) = value {
257                Name::parse(&json, None).map_err(Error::custom)
258            } else {
259                Err(Error::custom(format!("Expected a JSON object: {value:?}")))
260            }
261        })
262    }
263}
264
265/// Newtype pattern for `Name` to better control the `serde_json::Value` representation.
266///
267/// Aliases are serialized as an array of plain strings in the JSON representation.
268#[derive(Clone, Debug, Hash, PartialEq, Eq)]
269pub struct Alias(Name);
270
271impl Alias {
272    pub fn new(name: impl Into<String> + AsRef<str>) -> AvroResult<Self> {
273        Name::new(name).map(Self)
274    }
275
276    /// Create a new `Alias` using the namespace from `enclosing_namespace` if absent.
277    pub fn new_with_enclosing_namespace(
278        name: impl Into<String> + AsRef<str>,
279        enclosing_namespace: NamespaceRef,
280    ) -> AvroResult<Self> {
281        Name::new_with_enclosing_namespace(name, enclosing_namespace).map(Self)
282    }
283
284    pub fn name(&self) -> &str {
285        self.0.name()
286    }
287
288    pub fn namespace(&self) -> NamespaceRef<'_> {
289        self.0.namespace()
290    }
291
292    pub fn fullname(&self, enclosing_namespace: NamespaceRef) -> String {
293        self.0.fullname(enclosing_namespace)
294    }
295
296    pub fn fully_qualified_name(&self, default_namespace: NamespaceRef) -> Cow<'_, Name> {
297        self.0.fully_qualified_name(default_namespace)
298    }
299}
300
301impl TryFrom<&str> for Alias {
302    type Error = Error;
303
304    fn try_from(value: &str) -> Result<Self, Self::Error> {
305        Self::new(value)
306    }
307}
308
309impl TryFrom<String> for Alias {
310    type Error = Error;
311
312    fn try_from(value: String) -> Result<Self, Self::Error> {
313        Self::new(&value)
314    }
315}
316
317impl FromStr for Alias {
318    type Err = Error;
319
320    fn from_str(s: &str) -> Result<Self, Self::Err> {
321        Self::new(s)
322    }
323}
324
325impl Serialize for Alias {
326    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
327    where
328        S: Serializer,
329    {
330        serializer.serialize_str(&self.fullname(None))
331    }
332}
333
334#[cfg(test)]
335mod tests {
336    use crate::Error;
337
338    use super::*;
339    use apache_avro_test_helper::TestResult;
340
341    #[test]
342    /// Zero-length namespace is considered as no-namespace.
343    fn test_namespace_from_name_with_empty_value() -> TestResult {
344        let name = Name::new(".name")?;
345        assert_eq!(name.namespace_and_name, "name");
346        assert_eq!(name.index_of_name, 0);
347
348        Ok(())
349    }
350
351    #[test]
352    /// Whitespace is not allowed in the name.
353    fn test_name_with_whitespace_value() {
354        match Name::new(" ").map_err(Error::into_details) {
355            Err(Details::InvalidSchemaName(_, _)) => {}
356            _ => panic!("Expected an Details::InvalidSchemaName!"),
357        }
358    }
359
360    #[test]
361    /// The name must be non-empty.
362    fn test_name_with_no_name_part() {
363        match Name::new("space.").map_err(Error::into_details) {
364            Err(Details::InvalidSchemaName(_, _)) => {}
365            _ => panic!("Expected an Details::InvalidSchemaName!"),
366        }
367    }
368
369    /// A test cases showing that names and namespaces can be constructed
370    /// entirely by underscores.
371    #[test]
372    fn test_avro_3897_funny_valid_names_and_namespaces() -> TestResult {
373        for funny_name in ["_", "_._", "__._", "_.__", "_._._"] {
374            let name = Name::new(funny_name);
375            assert!(name.is_ok());
376        }
377        Ok(())
378    }
379}
apache_avro/schema/name.rs

apache_avro/schema/
name.rs
