Render a pretty hexdump in the logs

Cargo.toml

@@ -14,6 +14,7 @@ include = ["src/**/*", "Cargo.toml", "LICENSE-*.txt"]
 [dependencies]
 log = "0.4"
 nom = "6.0"
+pretty-hex = "0.2"
 
 [dev-dependencies]
 simplelog = "0.8"

src/error.rs

@@ -0,0 +1,27 @@
+use nom::error::Error;
+use nom::Err;
+use pretty_hex::pretty_hex;
+
+fn error_to_string(e: Error<&[u8]>) -> String {
+    format!(
+        "parsing error: {:?}: input:{}",
+        e.code,
+        get_pretty_hex(&e.input)
+    )
+}
+
+pub(crate) fn get_pretty_hex(input: &[u8]) -> String {
+    let mut s = String::new();
+    for l in pretty_hex(&input).split('\n') {
+        s += &format!("\n{}", l);
+    }
+    s
+}
+
+pub(crate) fn nom_err_to_string(e: Err<Error<&[u8]>>) -> String {
+    match e {
+        Err::Incomplete(_) => e.to_string(),
+        Err::Error(er) => error_to_string(er),
+        Err::Failure(er) => error_to_string(er),
+    }
+}

src/io.rs

@@ -1,3 +1,4 @@
+use crate::error::get_pretty_hex;
 use std::io::{self, ErrorKind, Read};
 use std::sync::mpsc::Sender;
 
@@ -34,7 +35,7 @@ fn do_read_stdin(tx: &Sender<Vec<u8>>) -> Result<(), String> {
                     let pos = id + 1;
                     let mut line = Vec::with_capacity(pos);
                     line.extend_from_slice(&line_buffer[..pos]);
-                    log::trace!("new line: {:?}", &line);
+                    log::trace!("new line:{}", get_pretty_hex(&line));
                     tx.send(line).unwrap();
                     line_buffer.drain(..pos);
                 }

src/lib.rs

@@ -45,6 +45,7 @@
 
 mod data_line;
 mod data_structures;
+mod error;
 mod filter;
 mod io;
 mod parsers;

src/parsers/parameters.rs

@@ -339,12 +339,7 @@ mod tests {
 
     #[test]
     fn test_invalid_parse_filter_auth() {
-        let test_vectors = vec![
-            "|\n",
-            "|\r\n",
-            "|derp",
-            "|derp|derpson\n",
-        ];
+        let test_vectors = vec!["|\n", "|\r\n", "|derp", "|derp|derpson\n"];
         for test in test_vectors {
             let res = parse_filter_auth(test.as_bytes());
             assert!(!res.is_ok());

src/process.rs

@@ -1,3 +1,4 @@
+use crate::error::nom_err_to_string;
 use crate::parsers::entry::{parse_entry, EntryOption};
 use crate::parsers::parameters::{
     parse_filter_auth, parse_filter_connect, parse_filter_data_line, parse_filter_ehlo,
@@ -147,7 +148,7 @@ pub(crate) fn line<T>(user_object: &mut T, input: &[u8]) -> Result<(), String>
 where
     T: Filter,
 {
-    let (input, entry) = parse_entry(input).map_err(|e| e.to_string())?;
+    let (input, entry) = parse_entry(input).map_err(nom_err_to_string)?;
     match entry {
         EntryOption::Report(r) => handle_reports!(user_object, r, input),
         EntryOption::Filter(f) => {