refactor progress

grep/src/lib.rs

@@ -0,0 +1,72 @@
+extern crate memchr;
+extern crate regex;
+extern crate regex_syntax as syntax;
+
+use std::error;
+use std::fmt;
+use std::result;
+
+pub use search::{Grep, GrepBuilder};
+
+mod literals;
+mod nonl;
+mod search;
+
+/// Result is a convenient type alias that fixes the type of the error to
+/// the `Error` type defined in this crate.
+pub type Result<T> = result::Result<T, Error>;
+
+/// Error enumerates the list of possible error conditions when building or
+/// using a `Grep` line searcher.
+#[derive(Debug)]
+pub enum Error {
+    /// An error from parsing or compiling a regex.
+    Regex(regex::Error),
+    /// This error occurs when an illegal literal was found in the regex
+    /// pattern. For example, if the line terminator is `\n` and the regex
+    /// pattern is `\w+\n\w+`, then the presence of `\n` will cause this error.
+    LiteralNotAllowed(char),
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match *self {
+            Error::Regex(ref err) => err.description(),
+            Error::LiteralNotAllowed(_) => "use of forbidden literal",
+            Error::__Nonexhaustive => unreachable!(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match *self {
+            Error::Regex(ref err) => err.cause(),
+            _ => None,
+        }
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Error::Regex(ref err) => err.fmt(f),
+            Error::LiteralNotAllowed(chr) => {
+                write!(f, "Literal '{}' not allowed.", chr)
+            }
+            Error::__Nonexhaustive => unreachable!(),
+        }
+    }
+}
+
+impl From<regex::Error> for Error {
+    fn from(err: regex::Error) -> Error {
+        Error::Regex(err)
+    }
+}
+
+impl From<syntax::Error> for Error {
+    fn from(err: syntax::Error) -> Error {
+        Error::Regex(regex::Error::Syntax(err))
+    }
+}