1 // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
2 // Copyright by contributors to this project.
3 // SPDX-License-Identifier: (Apache-2.0 OR MIT)
4
5 use core::fmt::{self, Debug};
6
7 const DEFAULT_BYTES_TYPE_NAME: &str = "Bytes";
8
pretty_bytes(bytes: &[u8]) -> PrettyBytes<'_>9 pub fn pretty_bytes(bytes: &[u8]) -> PrettyBytes<'_> {
10 PrettyBytes {
11 ty: None,
12 bytes,
13 show_len: true,
14 show_raw: false,
15 }
16 }
17
18 pub struct PrettyBytes<'a> {
19 ty: Option<&'a str>,
20 bytes: &'a [u8],
21 show_len: bool,
22 show_raw: bool,
23 }
24
25 impl<'a> PrettyBytes<'a> {
named(self, ty: &'a str) -> Self26 pub fn named(self, ty: &'a str) -> Self {
27 Self {
28 ty: Some(ty),
29 ..self
30 }
31 }
32
show_len(self, show: bool) -> Self33 pub fn show_len(self, show: bool) -> Self {
34 Self {
35 show_len: show,
36 ..self
37 }
38 }
39
show_raw(self, show: bool) -> Self40 pub fn show_raw(self, show: bool) -> Self {
41 Self {
42 show_raw: show,
43 ..self
44 }
45 }
46 }
47
48 impl Debug for PrettyBytes<'_> {
fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result49 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
50 let show_raw = self.show_raw || f.alternate();
51 match (self.ty, self.show_len, show_raw) {
52 (_, false, false) => show_only_type(self.ty, f),
53 (None, false, true) => show_only_raw(self.bytes, f),
54 (Some(ty), false, true) => show_newtype(ty, self.bytes, f),
55 (_, true, _) => show_struct(self.ty, self.bytes, show_raw, f),
56 }
57 }
58 }
59
show_only_type(ty: Option<&str>, f: &mut fmt::Formatter<'_>) -> fmt::Result60 fn show_only_type(ty: Option<&str>, f: &mut fmt::Formatter<'_>) -> fmt::Result {
61 f.write_str(ty.unwrap_or(DEFAULT_BYTES_TYPE_NAME))
62 }
63
show_only_raw(bytes: &[u8], f: &mut fmt::Formatter<'_>) -> fmt::Result64 fn show_only_raw(bytes: &[u8], f: &mut fmt::Formatter<'_>) -> fmt::Result {
65 f.write_str(&hex::encode(bytes))
66 }
67
show_newtype(ty: &str, bytes: &[u8], f: &mut fmt::Formatter<'_>) -> fmt::Result68 fn show_newtype(ty: &str, bytes: &[u8], f: &mut fmt::Formatter<'_>) -> fmt::Result {
69 write!(f, "{ty}({})", hex::encode(bytes))
70 }
71
show_struct( ty: Option<&str>, bytes: &[u8], show_raw: bool, f: &mut fmt::Formatter<'_>, ) -> fmt::Result72 fn show_struct(
73 ty: Option<&str>,
74 bytes: &[u8],
75 show_raw: bool,
76 f: &mut fmt::Formatter<'_>,
77 ) -> fmt::Result {
78 let ty = ty.unwrap_or(DEFAULT_BYTES_TYPE_NAME);
79 let mut out = f.debug_struct(ty);
80 out.field("len", &bytes.len());
81 if show_raw {
82 out.field("raw", &hex::encode(bytes));
83 }
84 out.finish()
85 }
86
pretty_with<F>(f: F) -> impl Debug where F: Fn(&mut fmt::Formatter<'_>) -> fmt::Result,87 pub fn pretty_with<F>(f: F) -> impl Debug
88 where
89 F: Fn(&mut fmt::Formatter<'_>) -> fmt::Result,
90 {
91 PrettyWith(f)
92 }
93
94 struct PrettyWith<F>(F);
95
96 impl<F> Debug for PrettyWith<F>
97 where
98 F: Fn(&mut fmt::Formatter<'_>) -> fmt::Result,
99 {
fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result100 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
101 self.0(f)
102 }
103 }
104
pretty_group_id(id: &[u8]) -> impl Debug + '_105 pub fn pretty_group_id(id: &[u8]) -> impl Debug + '_ {
106 pretty_bytes(id).show_len(false).show_raw(true)
107 }
108
109 #[cfg(test)]
110 mod tests {
111 use crate::debug::pretty_bytes;
112
113 #[test]
default_format_contains_only_length()114 fn default_format_contains_only_length() {
115 let bytes = pretty_bytes(b"foobar");
116 let output = format!("{bytes:?}");
117 assert!(output.contains("len"));
118 assert!(!output.contains("raw"));
119 assert!(!output.contains(&hex::encode(b"foobar")));
120 }
121
122 #[test]
alternate_format_contains_length_and_hex_encoded_bytes()123 fn alternate_format_contains_length_and_hex_encoded_bytes() {
124 let bytes = pretty_bytes(b"foobar");
125 let output = format!("{bytes:#?}");
126 assert!(output.contains("len"));
127 assert!(output.contains("raw"));
128 assert!(output.contains(&hex::encode(b"foobar")));
129 }
130 }
131