Add --files-without-matches flag.

Performs the opposite of --files-with-matches: only shows paths of
files that contain zero matches.

Closes #138

8 files changed, 92 insertions, 7 deletions

diff --git a/doc/rg.1 b/doc/rg.1
index bc756317..2442a43f 100644
--- a/doc/rg.1
+++ b/doc/rg.1
@@ -182,6 +182,11 @@ Only show path of each file with matches.
 .RS
 .RE
 .TP
+.B \-\-files\-without\-matches
+Only show path of each file with no matches.
+.RS
+.RE
+.TP
 .B \-H, \-\-with\-filename
 Prefix each match with the file name that contains it.
 This is the default when more than one file is searched.
diff --git a/doc/rg.1.md b/doc/rg.1.md
index a3d37667..3980e873 100644
--- a/doc/rg.1.md
+++ b/doc/rg.1.md
@@ -119,6 +119,9 @@ Project home page: https://github.com/BurntSushi/ripgrep
 -l, --files-with-matches
 : Only show path of each file with matches.
 
+--files-without-matches
+: Only show path of each file with no matches.
+
 -H, --with-filename
 : Prefix each match with the file name that contains it. This is the
   default when more than one file is searched.
diff --git a/src/app.rs b/src/app.rs
index 5edaf999..a549bc59 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -124,6 +124,7 @@ fn app<F>(next_line_help: bool, doc: F) -> App<'static, 'static>
              .value_name("FILE").takes_value(true)
              .multiple(true).number_of_values(1))
         .arg(flag("files-with-matches").short("l"))
+        .arg(flag("files-without-matches"))
         .arg(flag("with-filename").short("H"))
         .arg(flag("no-filename"))
         .arg(flag("heading"))
@@ -304,6 +305,8 @@ lazy_static! {
               lines, and the newline is not counted as part of the pattern.");
         doc!(h, "files-with-matches",
              "Only show the path of each file with at least one match.");
+        doc!(h, "files-without-matches",
+             "Only show the path of each file that contains zero matches.");
         doc!(h, "with-filename",
              "Show file name for each match.",
              "Prefix each match with the file name that contains it. This is \
diff --git a/src/args.rs b/src/args.rs
index a4955d5f..58cdee61 100644
--- a/src/args.rs
+++ b/src/args.rs
@@ -44,6 +44,7 @@ pub struct Args {
     context_separator: Vec<u8>,
     count: bool,
     files_with_matches: bool,
+    files_without_matches: bool,
     eol: u8,
     files: bool,
     follow: bool,
@@ -158,7 +159,7 @@ impl Args {
 
     /// Retrieve the configured file separator.
     pub fn file_separator(&self) -> Option<Vec<u8>> {
-        if self.heading && !self.count && !self.files_with_matches {
+        if self.heading && !self.count && !self.files_with_matches && !self.files_without_matches {
             Some(b"".to_vec())
         } else if self.before_context > 0 || self.after_context > 0 {
             Some(self.context_separator.clone())
@@ -217,6 +218,7 @@ impl Args {
             .before_context(self.before_context)
             .count(self.count)
             .files_with_matches(self.files_with_matches)
+            .files_without_matches(self.files_without_matches)
             .eol(self.eol)
             .line_number(self.line_number)
             .invert_match(self.invert_match)
@@ -314,6 +316,7 @@ impl<'a> ArgMatches<'a> {
             context_separator: self.context_separator(),
             count: self.is_present("count"),
             files_with_matches: self.is_present("files-with-matches"),
+            files_without_matches: self.is_present("files-without-matches"),
             eol: b'\n',
             files: self.is_present("files"),
             follow: self.is_present("follow"),
diff --git a/src/search_buffer.rs b/src/search_buffer.rs
index c7c3bca0..16a161e1 100644
--- a/src/search_buffer.rs
+++ b/src/search_buffer.rs
@@ -61,6 +61,15 @@ impl<'a, W: Send + Terminal> BufferSearcher<'a, W> {
         self
     }
 
+    /// If enabled, searching will print the path of files that *don't* match
+    /// the given pattern.
+    ///
+    /// Disabled by default.
+    pub fn files_without_matches(mut self, yes: bool) -> Self {
+        self.opts.files_without_matches = yes;
+        self
+    }
+
     /// Set the end-of-line byte used by this searcher.
     pub fn eol(mut self, eol: u8) -> Self {
         self.opts.eol = eol;
@@ -133,6 +142,9 @@ impl<'a, W: Send + Terminal> BufferSearcher<'a, W> {
         if self.opts.files_with_matches && self.match_count > 0 {
             self.printer.path(self.path);
         }
+        if self.opts.files_without_matches && self.match_count == 0 {
+            self.printer.path(self.path);
+        }
         self.match_count
     }
 
@@ -278,6 +290,14 @@ and exhibited clearly, with a label attached.\
     }
 
     #[test]
+    fn files_without_matches() {
+        let (count, out) = search(
+            "zzzz", SHERLOCK, |s| s.files_without_matches(true));
+        assert_eq!(0, count);
+        assert_eq!(out, "/baz.rs\n");
+    }
+
+    #[test]
     fn max_count() {
         let (count, out) = search(
             "Sherlock", SHERLOCK, |s| s.max_count(Some(1)));
diff --git a/src/search_stream.rs b/src/search_stream.rs
index 6ef8c451..b92fa806 100644
--- a/src/search_stream.rs
+++ b/src/search_stream.rs
@@ -82,6 +82,7 @@ pub struct Options {
     pub before_context: usize,
     pub count: bool,
     pub files_with_matches: bool,
+    pub files_without_matches: bool,
     pub eol: u8,
     pub invert_match: bool,
     pub line_number: bool,
@@ -97,6 +98,7 @@ impl Default for Options {
             before_context: 0,
             count: false,
             files_with_matches: false,
+            files_without_matches: false,
             eol: b'\n',
             invert_match: false,
             line_number: false,
@@ -109,16 +111,17 @@ impl Default for Options {
 }
 
 impl Options {
-    /// Several options (--quiet, --count, --files-with-matches) imply that
-    /// we shouldn't ever display matches.
+    /// Several options (--quiet, --count, --files-with-matches,
+    /// --files-without-matches) imply that we shouldn't ever display matches.
     pub fn skip_matches(&self) -> bool {
-        self.count || self.files_with_matches || self.quiet
+        self.count || self.files_with_matches || self.files_without_matches
+        || self.quiet
     }
 
-    /// Some options (--quiet, --files-with-matches) imply that we can stop
-    /// searching after the first match.
+    /// Some options (--quiet, --files-with-matches, --files-without-matches)
+    /// imply that we can stop searching after the first match.
     pub fn stop_after_first_match(&self) -> bool {
-        self.files_with_matches || self.quiet
+        self.files_with_matches || self.files_without_matches || self.quiet
     }
 
     /// Returns true if the search should terminate based on the match count.
@@ -199,6 +202,14 @@ impl<'a, R: io::Read, W: Terminal + Send> Searcher<'a, R, W> {
         self
     }
 
+    /// If enabled, searching will print the path of files without any matches.
+    ///
+    /// Disabled by default.
+    pub fn files_without_matches(mut self, yes: bool) -> Self {
+        self.opts.files_without_matches = yes;
+        self
+    }
+
     /// Set the end-of-line byte used by this searcher.
     pub fn eol(mut self, eol: u8) -> Self {
         self.opts.eol = eol;
@@ -296,6 +307,8 @@ impl<'a, R: io::Read, W: Terminal + Send> Searcher<'a, R, W> {
             } else if self.opts.files_with_matches {
                 self.printer.path(self.path);
             }
+        } else if self.match_count == 0 && self.opts.files_without_matches {
+            self.printer.path(self.path);
         }
         Ok(self.match_count)
     }
@@ -987,6 +1000,14 @@ fn main() {
     }
 
     #[test]
+    fn files_without_matches() {
+        let (count, out) = search_smallcap(
+            "zzzz", SHERLOCK, |s| s.files_without_matches(true));
+        assert_eq!(0, count);
+        assert_eq!(out, "/baz.rs\n");
+    }
+
+    #[test]
     fn max_count() {
         let (count, out) = search_smallcap(
             "Sherlock", SHERLOCK, |s| s.max_count(Some(1)));
diff --git a/src/worker.rs b/src/worker.rs
index 0ade140a..23ed7549 100644
--- a/src/worker.rs
+++ b/src/worker.rs
@@ -31,6 +31,7 @@ struct Options {
     before_context: usize,
     count: bool,
     files_with_matches: bool,
+    files_without_matches: bool,
     eol: u8,
     invert_match: bool,
     line_number: bool,
@@ -48,6 +49,7 @@ impl Default for Options {
             before_context: 0,
             count: false,
             files_with_matches: false,
+            files_without_matches: false,
             eol: b'\n',
             invert_match: false,
             line_number: false,
@@ -112,6 +114,14 @@ impl WorkerBuilder {
         self
     }
 
+    /// If enabled, searching will print the path of files without any matches.
+    ///
+    /// Disabled by default.
+    pub fn files_without_matches(mut self, yes: bool) -> Self {
+        self.opts.files_without_matches = yes;
+        self
+    }
+
     /// Set the end-of-line byte used by this searcher.
     pub fn eol(mut self, eol: u8) -> Self {
         self.opts.eol = eol;
@@ -230,6 +240,7 @@ impl Worker {
             .before_context(self.opts.before_context)
             .count(self.opts.count)
             .files_with_matches(self.opts.files_with_matches)
+            .files_without_matches(self.opts.files_without_matches)
             .eol(self.opts.eol)
             .line_number(self.opts.line_number)
             .invert_match(self.opts.invert_match)
@@ -260,6 +271,7 @@ impl Worker {
         Ok(searcher
             .count(self.opts.count)
             .files_with_matches(self.opts.files_with_matches)
+            .files_without_matches(self.opts.files_without_matches)
             .eol(self.opts.eol)
             .line_number(self.opts.line_number)
             .invert_match(self.opts.invert_match)
diff --git a/tests/tests.rs b/tests/tests.rs
index bdafb298..66c2e51c 100644
--- a/tests/tests.rs
+++ b/tests/tests.rs
@@ -339,6 +339,14 @@ sherlock!(files_with_matches, "Sherlock", ".", |wd: WorkDir, mut cmd: Command| {
     assert_eq!(lines, expected);
 });
 
+sherlock!(files_without_matches, "Sherlock", ".", |wd: WorkDir, mut cmd: Command| {
+    wd.create("file.py", "foo");
+    cmd.arg("--files-without-matches");
+    let lines: String = wd.stdout(&mut cmd);
+    let expected = "file.py\n";
+    assert_eq!(lines, expected);
+});
+
 sherlock!(after_context, |wd: WorkDir, mut cmd: Command| {
     cmd.arg("-A").arg("1");
     let lines: String = wd.stdout(&mut cmd);
@@ -1059,6 +1067,16 @@ sherlock!(feature_89_files_with_matches, "Sherlock", ".",
 });
 
 // See: https://github.com/BurntSushi/ripgrep/issues/89
+sherlock!(feature_89_files_without_matches, "Sherlock", ".",
+|wd: WorkDir, mut cmd: Command| {
+    wd.create("file.py", "foo");
+    cmd.arg("--null").arg("--files-without-matches");
+
+    let lines: String = wd.stdout(&mut cmd);
+    assert_eq!(lines, "file.py\x00");
+});
+
+// See: https://github.com/BurntSushi/ripgrep/issues/89
 sherlock!(feature_89_count, "Sherlock", ".",
 |wd: WorkDir, mut cmd: Command| {
     cmd.arg("--null").arg("--count");