apache_avro/
util.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::{AvroResult, error::Details, schema::Documentation};
19use serde_json::{Map, Value};
20use std::{
21    io::{Read, Write},
22    sync::{
23        Once,
24        atomic::{AtomicBool, AtomicUsize, Ordering},
25    },
26};
27
28/// Maximum number of bytes that can be allocated when decoding
29/// Avro-encoded values. This is a protection against ill-formed
30/// data, whose length field might be interpreted as enormous.
31/// See max_allocation_bytes to change this limit.
32pub const DEFAULT_MAX_ALLOCATION_BYTES: usize = 512 * 1024 * 1024;
33static MAX_ALLOCATION_BYTES: AtomicUsize = AtomicUsize::new(DEFAULT_MAX_ALLOCATION_BYTES);
34static MAX_ALLOCATION_BYTES_ONCE: Once = Once::new();
35
36/// Whether to set serialization & deserialization traits
37/// as `human_readable` or not.
38/// See [set_serde_human_readable] to change this value.
39// crate-visible for testing
40pub(crate) static SERDE_HUMAN_READABLE: AtomicBool = AtomicBool::new(true);
41static SERDE_HUMAN_READABLE_ONCE: Once = Once::new();
42
43pub trait MapHelper {
44    fn string(&self, key: &str) -> Option<String>;
45
46    fn name(&self) -> Option<String> {
47        self.string("name")
48    }
49
50    fn doc(&self) -> Documentation {
51        self.string("doc")
52    }
53
54    fn aliases(&self) -> Option<Vec<String>>;
55}
56
57impl MapHelper for Map<String, Value> {
58    fn string(&self, key: &str) -> Option<String> {
59        self.get(key)
60            .and_then(|v| v.as_str())
61            .map(|v| v.to_string())
62    }
63
64    fn aliases(&self) -> Option<Vec<String>> {
65        // FIXME no warning when aliases aren't a json array of json strings
66        self.get("aliases")
67            .and_then(|aliases| aliases.as_array())
68            .and_then(|aliases| {
69                aliases
70                    .iter()
71                    .map(|alias| alias.as_str())
72                    .map(|alias| alias.map(|a| a.to_string()))
73                    .collect::<Option<_>>()
74            })
75    }
76}
77
78pub fn read_long<R: Read>(reader: &mut R) -> AvroResult<i64> {
79    zag_i64(reader)
80}
81
82pub fn zig_i32<W: Write>(n: i32, buffer: W) -> AvroResult<usize> {
83    zig_i64(n as i64, buffer)
84}
85
86pub fn zig_i64<W: Write>(n: i64, writer: W) -> AvroResult<usize> {
87    encode_variable(((n << 1) ^ (n >> 63)) as u64, writer)
88}
89
90pub fn zag_i32<R: Read>(reader: &mut R) -> AvroResult<i32> {
91    let i = zag_i64(reader)?;
92    i32::try_from(i).map_err(|e| Details::ZagI32(e, i).into())
93}
94
95pub fn zag_i64<R: Read>(reader: &mut R) -> AvroResult<i64> {
96    let z = decode_variable(reader)?;
97    Ok(if z & 0x1 == 0 {
98        (z >> 1) as i64
99    } else {
100        !(z >> 1) as i64
101    })
102}
103
104fn encode_variable<W: Write>(mut z: u64, mut writer: W) -> AvroResult<usize> {
105    let mut buffer = [0u8; 10];
106    let mut i: usize = 0;
107    loop {
108        if z <= 0x7F {
109            buffer[i] = (z & 0x7F) as u8;
110            i += 1;
111            break;
112        } else {
113            buffer[i] = (0x80 | (z & 0x7F)) as u8;
114            i += 1;
115            z >>= 7;
116        }
117    }
118    writer
119        .write(&buffer[..i])
120        .map_err(|e| Details::WriteBytes(e).into())
121}
122
123fn decode_variable<R: Read>(reader: &mut R) -> AvroResult<u64> {
124    let mut i = 0u64;
125    let mut buf = [0u8; 1];
126
127    let mut j = 0;
128    loop {
129        if j > 9 {
130            // if j * 7 > 64
131            return Err(Details::IntegerOverflow.into());
132        }
133        reader
134            .read_exact(&mut buf[..])
135            .map_err(Details::ReadVariableIntegerBytes)?;
136        i |= (u64::from(buf[0] & 0x7F)) << (j * 7);
137        if (buf[0] >> 7) == 0 {
138            break;
139        } else {
140            j += 1;
141        }
142    }
143
144    Ok(i)
145}
146
147/// Set a new maximum number of bytes that can be allocated when decoding data.
148/// Once called, the limit cannot be changed.
149///
150/// **NOTE** This function must be called before decoding **any** data. The
151/// library leverages [`std::sync::Once`](https://doc.rust-lang.org/std/sync/struct.Once.html)
152/// to set the limit either when calling this method, or when decoding for
153/// the first time.
154pub fn max_allocation_bytes(num_bytes: usize) -> usize {
155    MAX_ALLOCATION_BYTES_ONCE.call_once(|| {
156        MAX_ALLOCATION_BYTES.store(num_bytes, Ordering::Release);
157    });
158    MAX_ALLOCATION_BYTES.load(Ordering::Acquire)
159}
160
161pub fn safe_len(len: usize) -> AvroResult<usize> {
162    let max_bytes = max_allocation_bytes(DEFAULT_MAX_ALLOCATION_BYTES);
163
164    if len <= max_bytes {
165        Ok(len)
166    } else {
167        Err(Details::MemoryAllocation {
168            desired: len,
169            maximum: max_bytes,
170        }
171        .into())
172    }
173}
174
175/// Set whether serializing/deserializing is marked as human readable in serde traits.
176/// This will adjust the return value of `is_human_readable()` for both.
177/// Once called, the value cannot be changed.
178///
179/// **NOTE** This function must be called before serializing/deserializing **any** data. The
180/// library leverages [`std::sync::Once`](https://doc.rust-lang.org/std/sync/struct.Once.html)
181/// to set the limit either when calling this method, or when decoding for
182/// the first time.
183pub fn set_serde_human_readable(human_readable: bool) {
184    SERDE_HUMAN_READABLE_ONCE.call_once(|| {
185        SERDE_HUMAN_READABLE.store(human_readable, Ordering::Release);
186    });
187}
188
189pub(crate) fn is_human_readable() -> bool {
190    SERDE_HUMAN_READABLE.load(Ordering::Acquire)
191}
192
193#[cfg(test)]
194mod tests {
195    use super::*;
196    use apache_avro_test_helper::TestResult;
197    use pretty_assertions::assert_eq;
198
199    #[test]
200    fn test_zigzag() {
201        let mut a = Vec::new();
202        let mut b = Vec::new();
203        zig_i32(42i32, &mut a).unwrap();
204        zig_i64(42i64, &mut b).unwrap();
205        assert_eq!(a, b);
206    }
207
208    #[test]
209    fn test_zig_i64() {
210        let mut s = Vec::new();
211
212        zig_i64(0, &mut s).unwrap();
213        assert_eq!(s, [0]);
214
215        s.clear();
216        zig_i64(-1, &mut s).unwrap();
217        assert_eq!(s, [1]);
218
219        s.clear();
220        zig_i64(1, &mut s).unwrap();
221        assert_eq!(s, [2]);
222
223        s.clear();
224        zig_i64(-64, &mut s).unwrap();
225        assert_eq!(s, [127]);
226
227        s.clear();
228        zig_i64(64, &mut s).unwrap();
229        assert_eq!(s, [128, 1]);
230
231        s.clear();
232        zig_i64(i32::MAX as i64, &mut s).unwrap();
233        assert_eq!(s, [254, 255, 255, 255, 15]);
234
235        s.clear();
236        zig_i64(i32::MAX as i64 + 1, &mut s).unwrap();
237        assert_eq!(s, [128, 128, 128, 128, 16]);
238
239        s.clear();
240        zig_i64(i32::MIN as i64, &mut s).unwrap();
241        assert_eq!(s, [255, 255, 255, 255, 15]);
242
243        s.clear();
244        zig_i64(i32::MIN as i64 - 1, &mut s).unwrap();
245        assert_eq!(s, [129, 128, 128, 128, 16]);
246
247        s.clear();
248        zig_i64(i64::MAX, &mut s).unwrap();
249        assert_eq!(s, [254, 255, 255, 255, 255, 255, 255, 255, 255, 1]);
250
251        s.clear();
252        zig_i64(i64::MIN, &mut s).unwrap();
253        assert_eq!(s, [255, 255, 255, 255, 255, 255, 255, 255, 255, 1]);
254    }
255
256    #[test]
257    fn test_zig_i32() {
258        let mut s = Vec::new();
259        zig_i32(i32::MAX / 2, &mut s).unwrap();
260        assert_eq!(s, [254, 255, 255, 255, 7]);
261
262        s.clear();
263        zig_i32(i32::MIN / 2, &mut s).unwrap();
264        assert_eq!(s, [255, 255, 255, 255, 7]);
265
266        s.clear();
267        zig_i32(-(i32::MIN / 2), &mut s).unwrap();
268        assert_eq!(s, [128, 128, 128, 128, 8]);
269
270        s.clear();
271        zig_i32(i32::MIN / 2 - 1, &mut s).unwrap();
272        assert_eq!(s, [129, 128, 128, 128, 8]);
273
274        s.clear();
275        zig_i32(i32::MAX, &mut s).unwrap();
276        assert_eq!(s, [254, 255, 255, 255, 15]);
277
278        s.clear();
279        zig_i32(i32::MIN, &mut s).unwrap();
280        assert_eq!(s, [255, 255, 255, 255, 15]);
281    }
282
283    #[test]
284    fn test_overflow() {
285        let causes_left_shift_overflow: &[u8] = &[0xe1, 0xe1, 0xe1, 0xe1, 0xe1];
286        assert!(decode_variable(&mut &*causes_left_shift_overflow).is_err());
287    }
288
289    #[test]
290    fn test_safe_len() -> TestResult {
291        assert_eq!(42usize, safe_len(42usize)?);
292        assert!(safe_len(1024 * 1024 * 1024).is_err());
293
294        Ok(())
295    }
296}
apache_avro/util.rs

apache_avro/
util.rs
