opendal/layers/
type_eraser.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 crate::raw::*;
19use crate::*;
20use std::fmt::Debug;
21use std::fmt::Formatter;
22
23/// TypeEraseLayer will erase the types on internal accessor.
24///
25/// For example, we will erase `Self::Reader` to `oio::Reader` (`Box<dyn oio::Read>`).
26///
27/// # Notes
28///
29/// TypeEraseLayer is not a public accessible layer that can be used by
30/// external users. We use this layer to erase any generic types.
31pub struct TypeEraseLayer;
32
33impl<A: Access> Layer<A> for TypeEraseLayer {
34    type LayeredAccess = TypeEraseAccessor<A>;
35
36    fn layer(&self, inner: A) -> Self::LayeredAccess {
37        TypeEraseAccessor { inner }
38    }
39}
40
41/// Provide reader wrapper for backend.
42pub struct TypeEraseAccessor<A: Access> {
43    inner: A,
44}
45
46impl<A: Access> Debug for TypeEraseAccessor<A> {
47    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
48        self.inner.fmt(f)
49    }
50}
51
52impl<A: Access> LayeredAccess for TypeEraseAccessor<A> {
53    type Inner = A;
54    type Reader = oio::Reader;
55    type Writer = oio::Writer;
56    type Lister = oio::Lister;
57    type Deleter = oio::Deleter;
58    type BlockingReader = oio::BlockingReader;
59    type BlockingWriter = oio::BlockingWriter;
60    type BlockingLister = oio::BlockingLister;
61    type BlockingDeleter = oio::BlockingDeleter;
62
63    fn inner(&self) -> &Self::Inner {
64        &self.inner
65    }
66
67    async fn read(&self, path: &str, args: OpRead) -> Result<(RpRead, Self::Reader)> {
68        self.inner
69            .read(path, args)
70            .await
71            .map(|(rp, r)| (rp, Box::new(r) as oio::Reader))
72    }
73
74    async fn write(&self, path: &str, args: OpWrite) -> Result<(RpWrite, Self::Writer)> {
75        self.inner
76            .write(path, args)
77            .await
78            .map(|(rp, w)| (rp, Box::new(w) as oio::Writer))
79    }
80
81    async fn delete(&self) -> Result<(RpDelete, Self::Deleter)> {
82        self.inner
83            .delete()
84            .await
85            .map(|(rp, p)| (rp, Box::new(p) as oio::Deleter))
86    }
87
88    async fn list(&self, path: &str, args: OpList) -> Result<(RpList, Self::Lister)> {
89        self.inner
90            .list(path, args)
91            .await
92            .map(|(rp, p)| (rp, Box::new(p) as oio::Lister))
93    }
94
95    fn blocking_read(&self, path: &str, args: OpRead) -> Result<(RpRead, Self::BlockingReader)> {
96        self.inner
97            .blocking_read(path, args)
98            .map(|(rp, r)| (rp, Box::new(r) as oio::BlockingReader))
99    }
100
101    fn blocking_write(&self, path: &str, args: OpWrite) -> Result<(RpWrite, Self::BlockingWriter)> {
102        self.inner
103            .blocking_write(path, args)
104            .map(|(rp, w)| (rp, Box::new(w) as oio::BlockingWriter))
105    }
106
107    fn blocking_delete(&self) -> Result<(RpDelete, Self::BlockingDeleter)> {
108        self.inner
109            .blocking_delete()
110            .map(|(rp, p)| (rp, Box::new(p) as oio::BlockingDeleter))
111    }
112
113    fn blocking_list(&self, path: &str, args: OpList) -> Result<(RpList, Self::BlockingLister)> {
114        self.inner
115            .blocking_list(path, args)
116            .map(|(rp, p)| (rp, Box::new(p) as oio::BlockingLister))
117    }
118}
opendal/layers/type_eraser.rs

opendal/layers/
type_eraser.rs
