2 files changed, 39 insertions, 7 deletions

diff --git a/crates/tools/src/lib.rs b/crates/tools/src/lib.rs
index 674b9d11f..d6c448f3b 100644
--- a/crates/tools/src/lib.rs
+++ b/crates/tools/src/lib.rs
@@ -1,7 +1,11 @@
 use std::{
     path::{Path, PathBuf},
     process::{Command, Stdio},
+    fs::OpenOptions,
+    io::{Write, Error, ErrorKind}
 };
+#[cfg(unix)]
+use std::os::unix::fs::OpenOptionsExt;
 
 use failure::bail;
 use itertools::Itertools;
@@ -39,7 +43,7 @@ pub fn collect_tests(s: &str) -> Vec<(usize, Test)> {
         let (start_line, name) = loop {
             match block.next() {
                 Some((idx, line)) if line.starts_with("test ") => {
-                    break (idx, line["test ".len()..].to_string())
+                    break (idx, line["test ".len()..].to_string());
                 }
                 Some(_) => (),
                 None => continue 'outer,
@@ -116,3 +120,26 @@ fn install_rustfmt() -> Result<()> {
         ".",
     )
 }
+
+pub fn install_format_hook() -> Result<()> {
+    let path = Path::new("./.git/hooks/pre-commit");
+    if !path.exists() {
+        let mut open_options = OpenOptions::new();
+        #[cfg(unix)]
+        {
+            // Set as executable
+            open_options.mode(0o770);
+        }
+        let mut file = open_options.write(true).create(true).open(path)?;
+        write!(
+            file,
+            r#"#!/bin/sh
+
+cargo format
+git update-index --add ."#
+        )?;
+    } else {
+        return Err(Error::new(ErrorKind::AlreadyExists, "Git hook already created").into());
+    }
+    Ok(())
+}
diff --git a/crates/tools/src/main.rs b/crates/tools/src/main.rs
index 36a7c83e2..9e90ac5c2 100644
--- a/crates/tools/src/main.rs
+++ b/crates/tools/src/main.rs
@@ -7,7 +7,7 @@ use std::{
 use clap::{App, Arg, SubCommand};
 use failure::bail;
 
-use tools::{collect_tests, generate, run, run_rustfmt, Mode, Overwrite, Result, Test, Verify};
+use tools::{collect_tests, generate, install_format_hook, run, run_rustfmt, Mode, Overwrite, Result, Test, Verify};
 
 const GRAMMAR_DIR: &str = "./crates/ra_syntax/src/grammar";
 const INLINE_TESTS_DIR: &str = "./crates/ra_syntax/tests/data/parser/inline";
@@ -25,17 +25,22 @@ fn main() -> Result<()> {
         .subcommand(SubCommand::with_name("gen-tests"))
         .subcommand(SubCommand::with_name("install-code"))
         .subcommand(SubCommand::with_name("format"))
+        .subcommand(SubCommand::with_name("format-hook"))
         .get_matches();
     let mode = if matches.is_present("verify") {
         Verify
     } else {
         Overwrite
     };
-    match matches.subcommand() {
-        ("install-code", _) => install_code_extension()?,
-        ("gen-tests", _) => gen_tests(mode)?,
-        ("gen-syntax", _) => generate(Overwrite)?,
-        ("format", _) => run_rustfmt(Overwrite)?,
+    match matches
+        .subcommand_name()
+        .expect("Subcommand must be specified")
+    {
+        "install-code" => install_code_extension()?,
+        "gen-tests" => gen_tests(mode)?,
+        "gen-syntax" => generate(Overwrite)?,
+        "format" => run_rustfmt(mode)?,
+        "format-hook" => install_format_hook()?,
         _ => unreachable!(),
     }
     Ok(())