Do not display binary files in interactive mode

closes #248

Cargo.lock

@@ -50,6 +50,7 @@ dependencies = [
  "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "console 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "content_inspector 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "directories 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "git2 0.7.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -148,6 +149,14 @@ dependencies = [
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "content_inspector"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "memchr 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "directories"
 version = "1.0.1"
@@ -830,6 +839,7 @@ dependencies = [
 "checksum clicolors-control 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1f84dec9bc083ce2503908cd305af98bd363da6f54bf8d4bf0ac14ee749ad5d1"
 "checksum cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
 "checksum console 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "ecd48adf136733979b49e15bc3b4c43cc0d3c85ece7bd08e6daa414c6fcb13e6"
+"checksum content_inspector 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d902e17eb0038a23c88baa0d78c75fac7968132e73f4fdb9ea77b03d2641b669"
 "checksum directories 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b106a38a9bf6c763c6c2e2c3332ab7635da453a68a6babca776386b3b287d338"
 "checksum error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "07e791d3be96241c77c43846b665ef1384606da2cd2a48730abe606a12906e02"
 "checksum flate2 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "37847f133aae7acf82bb9577ccd8bda241df836787642654286e79679826a54b"

Cargo.toml

@@ -22,6 +22,7 @@ console = "0.6"
 directories = "1.0"
 lazy_static = "1.0"
 wild = "2.0"
+content_inspector = "0.2.2"
 
 [dependencies.git2]
 version = "0.7"

src/main.rs

@@ -13,6 +13,7 @@ extern crate lazy_static;
 extern crate ansi_term;
 extern crate atty;
 extern crate console;
+extern crate content_inspector;
 extern crate directories;
 extern crate git2;
 extern crate syntect;

src/printer.rs

@@ -9,6 +9,8 @@ use console::AnsiCodeIterator;
 use syntect::easy::HighlightLines;
 use syntect::highlighting::Theme;
 
+use content_inspector::{self, ContentType};
+
 use app::Config;
 use assets::HighlightingAssets;
 use decorations::{Decoration, GridBorderDecoration, LineChangesDecoration, LineNumberDecoration};
@@ -69,8 +71,9 @@ pub struct InteractivePrinter<'a> {
     decorations: Vec<Box<dyn Decoration>>,
     panel_width: usize,
     ansi_prefix_sgr: String,
+    content_type: ContentType,
     pub line_changes: Option<LineChanges>,
-    highlighter: HighlightLines<'a>,
+    highlighter: Option<HighlightLines<'a>>,
 }
 
 impl<'a> InteractivePrinter<'a> {
@@ -118,19 +121,28 @@ impl<'a> InteractivePrinter<'a> {
             panel_width = 0;
         }
 
-        // Get the Git modifications
-        let line_changes = if config.output_components.changes() {
-            match file {
-                InputFile::Ordinary(filename) => get_git_diff(filename),
-                _ => None,
-            }
-        } else {
-            None
-        };
+        // Determine file content type
+        let content_type = content_inspector::inspect(&reader.first_line[..]);
 
-        // Determine the type of syntax for highlighting
-        let syntax = assets.get_syntax(config.language, file, reader);
-        let highlighter = HighlightLines::new(syntax, theme);
+        let mut line_changes = None;
+
+        let highlighter = if content_type.is_binary() {
+            None
+        } else {
+            // Get the Git modifications
+            line_changes = if config.output_components.changes() {
+                match file {
+                    InputFile::Ordinary(filename) => get_git_diff(filename),
+                    _ => None,
+                }
+            } else {
+                None
+            };
+
+            // Determine the type of syntax for highlighting
+            let syntax = assets.get_syntax(config.language, file, reader);
+            Some(HighlightLines::new(syntax, theme))
+        };
 
         InteractivePrinter {
             panel_width,
@@ -138,6 +150,7 @@ impl<'a> InteractivePrinter<'a> {
             config,
             decorations,
             ansi_prefix_sgr: String::new(),
+            content_type,
             line_changes,
             highlighter,
         }
@@ -194,17 +207,33 @@ impl<'a> Printer for InteractivePrinter<'a> {
             _ => ("", "STDIN"),
         };
 
-        writeln!(handle, "{}{}", prefix, self.colors.filename.paint(name))?;
+        let mode = if self.content_type.is_binary() {
+            "   <BINARY>"
+        } else {
+            ""
+        };
+
+        writeln!(
+            handle,
+            "{}{}{}",
+            prefix,
+            self.colors.filename.paint(name),
+            mode
+        )?;
 
         if self.config.output_components.grid() {
-            self.print_horizontal_line(handle, '┼')?;
+            if self.content_type.is_text() {
+                self.print_horizontal_line(handle, '┼')?;
+            } else {
+                self.print_horizontal_line(handle, '┴')?;
+            }
         }
 
         Ok(())
     }
 
     fn print_footer(&mut self, handle: &mut Write) -> Result<()> {
-        if self.config.output_components.grid() {
+        if self.config.output_components.grid() && self.content_type.is_text() {
             self.print_horizontal_line(handle, '┴')
         } else {
             Ok(())
@@ -219,7 +248,15 @@ impl<'a> Printer for InteractivePrinter<'a> {
         line_buffer: &[u8],
     ) -> Result<()> {
         let line = String::from_utf8_lossy(&line_buffer).to_string();
-        let regions = self.highlighter.highlight(line.as_ref());
+        let regions = {
+            let highlighter = match self.highlighter {
+                Some(ref mut highlighter) => highlighter,
+                _ => {
+                    return Ok(());
+                }
+            };
+            highlighter.highlight(line.as_ref())
+        };
 
         if out_of_range {
             return Ok(());