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Diffstat (limited to 'grep-cli/src/pattern.rs')
| -rw-r--r-- | grep-cli/src/pattern.rs | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/grep-cli/src/pattern.rs b/grep-cli/src/pattern.rs new file mode 100644 index 00000000..ed1d95a5 --- /dev/null +++ b/grep-cli/src/pattern.rs @@ -0,0 +1,205 @@ +use std::error; +use std::ffi::OsStr; +use std::fmt; +use std::fs::File; +use std::io::{self, BufRead}; +use std::path::Path; +use std::str; + +use escape::{escape, escape_os}; + +/// An error that occurs when a pattern could not be converted to valid UTF-8. +/// +/// The purpose of this error is to give a more targeted failure mode for +/// patterns written by end users that are not valid UTF-8. +#[derive(Clone, Debug, Eq, PartialEq)] +pub struct InvalidPatternError { + original: String, + valid_up_to: usize, +} + +impl InvalidPatternError { + /// Returns the index in the given string up to which valid UTF-8 was + /// verified. + pub fn valid_up_to(&self) -> usize { + self.valid_up_to + } +} + +impl error::Error for InvalidPatternError { + fn description(&self) -> &str { "invalid pattern" } +} + +impl fmt::Display for InvalidPatternError { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + write!( + f, + "found invalid UTF-8 in pattern at byte offset {} \ + (use hex escape sequences to match arbitrary bytes \ + in a pattern, e.g., \\xFF): '{}'", + self.valid_up_to, + self.original, + ) + } +} + +impl From<InvalidPatternError> for io::Error { + fn from(paterr: InvalidPatternError) -> io::Error { + io::Error::new(io::ErrorKind::Other, paterr) + } +} + +/// Convert an OS string into a regular expression pattern. +/// +/// This conversion fails if the given pattern is not valid UTF-8, in which +/// case, a targeted error with more information about where the invalid UTF-8 +/// occurs is given. The error also suggests the use of hex escape sequences, +/// which are supported by many regex engines. +pub fn pattern_from_os(pattern: &OsStr) -> Result<&str, InvalidPatternError> { + pattern.to_str().ok_or_else(|| { + let valid_up_to = pattern + .to_string_lossy() + .find('\u{FFFD}') + .expect("a Unicode replacement codepoint for invalid UTF-8"); + InvalidPatternError { + original: escape_os(pattern), + valid_up_to: valid_up_to, + } + }) +} + +/// Convert arbitrary bytes into a regular expression pattern. +/// +/// This conversion fails if the given pattern is not valid UTF-8, in which +/// case, a targeted error with more information about where the invalid UTF-8 +/// occurs is given. The error also suggests the use of hex escape sequences, +/// which are supported by many regex engines. +pub fn pattern_from_bytes( + pattern: &[u8], +) -> Result<&str, InvalidPatternError> { + str::from_utf8(pattern).map_err(|err| { + InvalidPatternError { + original: escape(pattern), + valid_up_to: err.valid_up_to(), + } + }) +} + +/// Read patterns from a file path, one per line. +/// +/// If there was a problem reading or if any of the patterns contain invalid +/// UTF-8, then an error is returned. If there was a problem with a specific +/// pattern, then the error message will include the line number and the file +/// path. +pub fn patterns_from_path<P: AsRef<Path>>(path: P) -> io::Result<Vec<String>> { + let path = path.as_ref(); + let file = File::open(path).map_err(|err| { + io::Error::new( + io::ErrorKind::Other, + format!("{}: {}", path.display(), err), + ) + })?; + patterns_from_reader(file).map_err(|err| { + io::Error::new( + io::ErrorKind::Other, + format!("{}:{}", path.display(), err), + ) + }) +} + +/// Read patterns from stdin, one per line. +/// +/// If there was a problem reading or if any of the patterns contain invalid +/// UTF-8, then an error is returned. If there was a problem with a specific +/// pattern, then the error message will include the line number and the fact +/// that it came from stdin. +pub fn patterns_from_stdin() -> io::Result<Vec<String>> { + let stdin = io::stdin(); + let locked = stdin.lock(); + patterns_from_reader(locked).map_err(|err| { + io::Error::new( + io::ErrorKind::Other, + format!("<stdin>:{}", err), + ) + }) +} + +/// Read patterns from any reader, one per line. +/// +/// If there was a problem reading or if any of the patterns contain invalid +/// UTF-8, then an error is returned. If there was a problem with a specific +/// pattern, then the error message will include the line number. +/// +/// Note that this routine uses its own internal buffer, so the caller should +/// not provide their own buffered reader if possible. +/// +/// # Example +/// +/// This shows how to parse patterns, one per line. +/// +/// ``` +/// use grep_cli::patterns_from_reader; +/// +/// # fn example() -> Result<(), Box<::std::error::Error>> { +/// let patterns = "\ +/// foo +/// bar\\s+foo +/// [a-z]{3} +/// "; +/// +/// assert_eq!(patterns_from_reader(patterns.as_bytes())?, vec![ +/// r"foo", +/// r"bar\s+foo", +/// r"[a-z]{3}", +/// ]); +/// # Ok(()) } +/// ``` +pub fn patterns_from_reader<R: io::Read>(rdr: R) -> io::Result<Vec<String>> { + let mut patterns = vec![]; + let mut bufrdr = io::BufReader::new(rdr); + let mut line = vec![]; + let mut line_number = 0; + while { + line.clear(); + line_number += 1; + bufrdr.read_until(b'\n', &mut line)? > 0 + } { + line.pop().unwrap(); // remove trailing '\n' + if line.last() == Some(&b'\r') { + line.pop().unwrap(); + } + match pattern_from_bytes(&line) { + Ok(pattern) => patterns.push(pattern.to_string()), + Err(err) => { + return Err(io::Error::new( + io::ErrorKind::Other, + format!("{}: {}", line_number, err), + )); + } + } + } + Ok(patterns) +} + +#[cfg(test)] +mod tests { + use super::{pattern_from_bytes, pattern_from_os}; + + #[test] + fn bytes() { + let pat = b"abc\xFFxyz"; + let err = pattern_from_bytes(pat).unwrap_err(); + assert_eq!(3, err.valid_up_to()); + } + + #[test] + #[cfg(unix)] + fn os() { + use std::os::unix::ffi::OsStrExt; + use std::ffi::OsStr; + + let pat = OsStr::from_bytes(b"abc\xFFxyz"); + let err = pattern_from_os(pat).unwrap_err(); + assert_eq!(3, err.valid_up_to()); + } +} |