From 613d4bd5d56d086ae0fc80746aa111c1ae6b7d2c Mon Sep 17 00:00:00 2001
From: Stepan Koltsov <stepan.koltsov@gmail.com>
Date: Tue, 21 Mar 2017 07:09:44 +0300
Subject: [PATCH] Reimplement fmt::Debug for Bytes and BytesMut (#84)
Standard `Debug` implementation for `[u8]` is comma separated list
of numbers. Since large amount of byte strings are in fact ASCII
strings or contain a lot of ASCII strings (e. g. HTTP), it is
convenient to print strings as ASCII when possible.
---
src/bytes.rs | 5 +++--
src/debug.rs | 40 ++++++++++++++++++++++++++++++++++++++++
src/lib.rs | 1 +
tests/test_bytes.rs | 2 +-
tests/test_debug.rs | 35 +++++++++++++++++++++++++++++++++++
5 files changed, 80 insertions(+), 3 deletions(-)
create mode 100644 src/debug.rs
create mode 100644 tests/test_debug.rs
diff --git a/src/bytes.rs b/src/bytes.rs
index 954c310..fcec6cc 100644
--- a/src/bytes.rs
+++ b/src/bytes.rs
@@ -1,5 +1,6 @@
use {IntoBuf, Buf, BufMut};
use buf::Iter;
+use debug;
use std::{cmp, fmt, mem, hash, ops, slice, ptr, usize};
use std::borrow::Borrow;
@@ -722,7 +723,7 @@ impl Eq for Bytes {
impl fmt::Debug for Bytes {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
- fmt::Debug::fmt(&self.inner.as_ref(), fmt)
+ fmt::Debug::fmt(&debug::BsDebug(&self.inner.as_ref()), fmt)
}
}
@@ -1260,7 +1261,7 @@ impl Eq for BytesMut {
impl fmt::Debug for BytesMut {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
- fmt::Debug::fmt(self.inner.as_ref(), fmt)
+ fmt::Debug::fmt(&debug::BsDebug(&self.inner.as_ref()), fmt)
}
}
diff --git a/src/debug.rs b/src/debug.rs
new file mode 100644
index 0000000..abead05
--- /dev/null
+++ b/src/debug.rs
@@ -0,0 +1,40 @@
+use std::fmt;
+
+/// Alternative implementation of `fmt::Debug` for byte slice.
+///
+/// Standard `Debug` implementation for `[u8]` is comma separated
+/// list of numbers. Since large amount of byte strings are in fact
+/// ASCII strings or contain a lot of ASCII strings (e. g. HTTP),
+/// it is convenient to print strings as ASCII when possible.
+///
+/// This struct wraps `&[u8]` just to override `fmt::Debug`.
+///
+/// `BsDebug` is not a part of public API of bytes crate.
+pub struct BsDebug<'a>(pub &'a [u8]);
+
+impl<'a> fmt::Debug for BsDebug<'a> {
+ fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+ try!(write!(fmt, "b\""));
+ for &c in self.0 {
+ // https://doc.rust-lang.org/reference.html#byte-escapes
+ if c == b'\n' {
+ try!(write!(fmt, "\\n"));
+ } else if c == b'\r' {
+ try!(write!(fmt, "\\r"));
+ } else if c == b'\t' {
+ try!(write!(fmt, "\\t"));
+ } else if c == b'\\' || c == b'"' {
+ try!(write!(fmt, "\\{}", c as char));
+ } else if c == b'\0' {
+ try!(write!(fmt, "\\0"));
+ // ASCII printable except space
+ } else if c > 0x20 && c < 0x7f {
+ try!(write!(fmt, "{}", c as char));
+ } else {
+ try!(write!(fmt, "\\x{:02x}", c));
+ }
+ }
+ try!(write!(fmt, "\""));
+ Ok(())
+ }
+}
diff --git a/src/lib.rs b/src/lib.rs
index fabba8a..42c2c8c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -89,6 +89,7 @@ pub use buf::{
};
mod bytes;
+mod debug;
pub use bytes::{Bytes, BytesMut};
pub use byteorder::{ByteOrder, BigEndian, LittleEndian};
diff --git a/tests/test_bytes.rs b/tests/test_bytes.rs
index 2e163df..5c2c91d 100644
--- a/tests/test_bytes.rs
+++ b/tests/test_bytes.rs
@@ -43,7 +43,7 @@ fn from_slice() {
#[test]
fn fmt() {
let a = format!("{:?}", Bytes::from(&b"abcdefg"[..]));
- let b = format!("{:?}", b"abcdefg");
+ let b = "b\"abcdefg\"";
assert_eq!(a, b);
diff --git a/tests/test_debug.rs b/tests/test_debug.rs
new file mode 100644
index 0000000..eec7bca
--- /dev/null
+++ b/tests/test_debug.rs
@@ -0,0 +1,35 @@
+extern crate bytes;
+
+use bytes::Bytes;
+
+#[test]
+fn fmt() {
+ let vec: Vec<_> = (0..0x100).map(|b| b as u8).collect();
+
+ let expected = "b\"\
+ \\0\\x01\\x02\\x03\\x04\\x05\\x06\\x07\
+ \\x08\\t\\n\\x0b\\x0c\\r\\x0e\\x0f\
+ \\x10\\x11\\x12\\x13\\x14\\x15\\x16\\x17\
+ \\x18\\x19\\x1a\\x1b\\x1c\\x1d\\x1e\\x1f\
+ \\x20!\\\"#$%&'()*+,-./0123456789:;<=>?\
+ @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\\\]^_\
+ `abcdefghijklmnopqrstuvwxyz{|}~\\x7f\
+ \\x80\\x81\\x82\\x83\\x84\\x85\\x86\\x87\
+ \\x88\\x89\\x8a\\x8b\\x8c\\x8d\\x8e\\x8f\
+ \\x90\\x91\\x92\\x93\\x94\\x95\\x96\\x97\
+ \\x98\\x99\\x9a\\x9b\\x9c\\x9d\\x9e\\x9f\
+ \\xa0\\xa1\\xa2\\xa3\\xa4\\xa5\\xa6\\xa7\
+ \\xa8\\xa9\\xaa\\xab\\xac\\xad\\xae\\xaf\
+ \\xb0\\xb1\\xb2\\xb3\\xb4\\xb5\\xb6\\xb7\
+ \\xb8\\xb9\\xba\\xbb\\xbc\\xbd\\xbe\\xbf\
+ \\xc0\\xc1\\xc2\\xc3\\xc4\\xc5\\xc6\\xc7\
+ \\xc8\\xc9\\xca\\xcb\\xcc\\xcd\\xce\\xcf\
+ \\xd0\\xd1\\xd2\\xd3\\xd4\\xd5\\xd6\\xd7\
+ \\xd8\\xd9\\xda\\xdb\\xdc\\xdd\\xde\\xdf\
+ \\xe0\\xe1\\xe2\\xe3\\xe4\\xe5\\xe6\\xe7\
+ \\xe8\\xe9\\xea\\xeb\\xec\\xed\\xee\\xef\
+ \\xf0\\xf1\\xf2\\xf3\\xf4\\xf5\\xf6\\xf7\
+ \\xf8\\xf9\\xfa\\xfb\\xfc\\xfd\\xfe\\xff\"";
+
+ assert_eq!(expected, format!("{:?}", Bytes::from(vec)));
+}
--
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