From 1c8379f55a6f07df0d28dc294ff80ad56f06459f Mon Sep 17 00:00:00 2001
From: Andrew Gallant <jamslam@gmail.com>
Date: Sun, 28 Aug 2016 01:37:12 -0400
Subject: Implementing core functionality.

Initially experimenting with crossbeam to manage synchronization.
---
 src/search.rs | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 144 insertions(+)
 create mode 100644 src/search.rs

(limited to 'src/search.rs')

diff --git a/src/search.rs b/src/search.rs
new file mode 100644
index 00000000..f0e297ab
--- /dev/null
+++ b/src/search.rs
@@ -0,0 +1,144 @@
+/*!
+The search module is responsible for searching a single file and printing
+matches.
+*/
+
+use std::cmp;
+use std::error::Error as StdError;
+use std::fmt;
+use std::fs::File;
+use std::io;
+use std::path::{Path, PathBuf};
+
+use grep::Grep;
+use memchr::memchr;
+use memmap::{Mmap, Protection};
+
+use printer::Printer;
+
+/// Error describes errors that can occur while searching.
+#[derive(Debug)]
+pub enum Error {
+    /// Normal IO or Mmap errors suck. Include the path the originated them.
+    Io {
+        err: io::Error,
+        path: PathBuf,
+    }
+}
+
+impl Error {
+    fn from_io<P: AsRef<Path>>(err: io::Error, path: P) -> Error {
+        Error::Io { err: err, path: path.as_ref().to_path_buf() }
+    }
+}
+
+impl StdError for Error {
+    fn description(&self) -> &str {
+        match *self {
+            Error::Io { ref err, .. } => err.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&StdError> {
+        match *self {
+            Error::Io { ref err, .. } => Some(err),
+        }
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Error::Io { ref err, ref path } => {
+                write!(f, "{}: {}", path.display(), err)
+            }
+        }
+    }
+}
+
+/// Searcher searches a memory mapped buffer.
+///
+/// The `'g` lifetime refers to the lifetime of the underlying matcher.
+pub struct Searcher<'g> {
+    grep: &'g Grep,
+    path: PathBuf,
+    mmap: Option<Mmap>,
+}
+
+impl<'g> Searcher<'g> {
+    /// Create a new memory map based searcher using the given matcher for the
+    /// file path given.
+    pub fn new<P: AsRef<Path>>(
+        grep: &'g Grep,
+        path: P,
+    ) -> Result<Searcher<'g>, Error> {
+        let file = try!(File::open(&path).map_err(|err| {
+            Error::from_io(err, &path)
+        }));
+        let md = try!(file.metadata().map_err(|err| {
+            Error::from_io(err, &path)
+        }));
+        let mmap =
+            if md.len() == 0 {
+                None
+            } else {
+                Some(try!(Mmap::open(&file, Protection::Read).map_err(|err| {
+                    Error::from_io(err, &path)
+                })))
+            };
+        Ok(Searcher {
+            grep: grep,
+            path: path.as_ref().to_path_buf(),
+            mmap: mmap,
+        })
+    }
+
+    /// Execute the search, writing the results to the printer given and
+    /// returning the underlying buffer.
+    pub fn search<W: io::Write>(&self, printer: Printer<W>) -> W {
+        Search {
+            grep: &self.grep,
+            path: &*self.path,
+            buf: self.buf(),
+            printer: printer,
+        }.run()
+    }
+
+    /// Execute the search, returning a count of the number of hits.
+    pub fn count(&self) -> u64 {
+        self.grep.iter(self.buf()).count() as u64
+    }
+
+    fn buf(&self) -> &[u8] {
+        self.mmap.as_ref().map(|m| unsafe { m.as_slice() }).unwrap_or(&[])
+    }
+}
+
+struct Search<'a, W> {
+    grep: &'a Grep,
+    path: &'a Path,
+    buf: &'a [u8],
+    printer: Printer<W>,
+}
+
+impl<'a, W: io::Write> Search<'a, W> {
+    fn run(mut self) -> W {
+        let is_binary = self.is_binary();
+        let mut it = self.grep.iter(self.buf).peekable();
+        if is_binary && it.peek().is_some() {
+            self.printer.binary_matched(self.path);
+            return self.printer.into_inner();
+        }
+        for m in it {
+            self.printer.matched(self.path, self.buf, &m);
+        }
+        self.printer.into_inner()
+    }
+
+    fn is_binary(&self) -> bool {
+        if self.buf.len() >= 4 && &self.buf[0..4] == b"%PDF" {
+            return true;
+        }
+        memchr(b'\x00', &self.buf[0..cmp::min(1024, self.buf.len())]).is_some()
+    }
+}
-- 
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