Add a --null flag.

This flag causes a NUL byte to follow any file path in ripgrep's output.

Closes #89.

src/args.rs

@@ -155,6 +155,12 @@ Less common options:
         Don't respect version control ignore files (e.g., .gitignore).
         Note that .ignore files will continue to be respected.
 
+    --null
+        Whenever a file name is printed, follow it with a NUL byte.
+        This includes printing filenames before matches, and when printing
+        a list of matching files such as with --count, --files-with-matches
+        and --files.
+
     -p, --pretty
         Alias for --color=always --heading -n.
 
@@ -224,6 +230,7 @@ pub struct RawArgs {
     flag_no_line_number: bool,
     flag_no_mmap: bool,
     flag_no_filename: bool,
+    flag_null: bool,
     flag_pretty: bool,
     flag_quiet: bool,
     flag_regexp: Vec<String>,
@@ -269,6 +276,7 @@ pub struct Args {
     no_ignore: bool,
     no_ignore_parent: bool,
     no_ignore_vcs: bool,
+    null: bool,
     quiet: bool,
     replace: Option<Vec<u8>>,
     text: bool,
@@ -399,6 +407,7 @@ impl RawArgs {
             no_ignore_vcs:
                 // --no-ignore implies --no-ignore-vcs
                 self.flag_no_ignore_vcs || no_ignore,
+            null: self.flag_null,
             quiet: self.flag_quiet,
             replace: self.flag_replace.clone().map(|s| s.into_bytes()),
             text: text,
@@ -553,6 +562,7 @@ impl Args {
             .heading(self.heading)
             .line_per_match(self.line_per_match)
             .quiet(self.quiet)
+            .null(self.null)
             .with_filename(self.with_filename);
         if let Some(ref rep) = self.replace {
             p = p.replace(rep.clone());

src/printer.rs

@@ -33,6 +33,9 @@ pub struct Printer<W> {
     line_per_match: bool,
     /// Whether to suppress all output.
     quiet: bool,
+    /// Whether to print NUL bytes after a file path instead of new lines
+    /// or `:`.
+    null: bool,
     /// A string to use as a replacement of each match in a matching line.
     replace: Option<Vec<u8>>,
     /// Whether to prefix each match with the corresponding file name.
@@ -51,6 +54,7 @@ impl<W: Terminal + Send> Printer<W> {
             heading: false,
             line_per_match: false,
             quiet: false,
+            null: false,
             replace: None,
             with_filename: false,
         }
@@ -89,6 +93,13 @@ impl<W: Terminal + Send> Printer<W> {
         self
     }
 
+    /// Whether to cause NUL bytes to follow file paths instead of other
+    /// visual separators (like `:`, `-` and `\n`).
+    pub fn null(mut self, yes: bool) -> Printer<W> {
+        self.null = yes;
+        self
+    }
+
     /// When set, all output is suppressed.
     pub fn quiet(mut self, yes: bool) -> Printer<W> {
         self.quiet = yes;
@@ -146,14 +157,22 @@ impl<W: Terminal + Send> Printer<W> {
     pub fn path<P: AsRef<Path>>(&mut self, path: P) {
         let path = strip_prefix("./", path.as_ref()).unwrap_or(path.as_ref());
         self.write_path(path);
-        self.write_eol();
+        if self.null {
+            self.write(b"\x00");
+        } else {
+            self.write_eol();
+        }
     }
 
     /// Prints the given path and a count of the number of matches found.
     pub fn path_count<P: AsRef<Path>>(&mut self, path: P, count: u64) {
         if self.with_filename {
             self.write_path(path);
-            self.write(b":");
+            if self.null {
+                self.write(b"\x00");
+            } else {
+                self.write(b":");
+            }
         }
         self.write(count.to_string().as_bytes());
         self.write_eol();
@@ -214,7 +233,11 @@ impl<W: Terminal + Send> Printer<W> {
             self.write_heading(path.as_ref());
         } else if !self.heading && self.with_filename {
             self.write_path(path.as_ref());
-            self.write(b":");
+            if self.null {
+                self.write(b"\x00");
+            } else {
+                self.write(b":");
+            }
         }
         if let Some(line_number) = line_number {
             self.line_number(line_number, b':');
@@ -264,7 +287,11 @@ impl<W: Terminal + Send> Printer<W> {
             self.write_heading(path.as_ref());
         } else if !self.heading && self.with_filename {
             self.write_path(path.as_ref());
-            self.write(b"-");
+            if self.null {
+                self.write(b"\x00");
+            } else {
+                self.write(b"-");
+            }
         }
         if let Some(line_number) = line_number {
             self.line_number(line_number, b'-');
@@ -281,7 +308,11 @@ impl<W: Terminal + Send> Printer<W> {
             let _ = self.wtr.attr(Attr::Bold);
         }
         self.write_path(path.as_ref());
-        self.write_eol();
+        if self.null {
+            self.write(b"\x00");
+        } else {
+            self.write_eol();
+        }
         if self.wtr.supports_color() {
             let _ = self.wtr.reset();
         }