git pre-commit hook to run rustfmt on modified files (#110)

* git pre-commit hook to run rustfmt on modified files
* add docs for rustfmt
* add CONTRIBUTING file

.gitignore

@@ -1,5 +1,7 @@
 *.swp
-.*
+.DS_Store
+.grin
+.grin2
 target
 Cargo.lock
 **.iml

.hooks/pre-commit

@@ -0,0 +1,50 @@
+#!/bin/bash
+
+# Copyright 2017 The Grin Developers
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+cargo +nightly fmt -- --version &>/dev/null
+if [ $? != 0 ]; then
+	printf "[pre_commit] \033[0;31merror\033[0m: \"cargo +nightly fmt\" not available?\n"
+	exit 1
+fi
+
+result=0
+problem_files=()
+
+printf "[pre_commit] rustfmt "
+for file in $(git diff --name-only --cached); do
+	if [ ${file: -3} == ".rs" ]; then
+        cargo +nightly fmt -- --skip-children --write-mode=diff $file &>/dev/null
+				if [ $? != 0 ]; then
+					problem_files+=($file)
+					result=1
+				fi
+	fi
+done
+
+if [ $result != 0 ]; then
+	printf "\033[0;31mfail\033[0m \n"
+  printf "[pre_commit] the following files need formatting: \n"
+
+	for file in $problem_files; do
+		printf "    cargo +nightly fmt -- $file\n"
+	done
+else
+  printf "\033[0;32mok\033[0m \n"
+fi
+
+exit 0
+# to actually fail the build on rustfmt failure -
+# exit $result

CONTRIBUTING.md

@@ -0,0 +1,16 @@
+# Contributing
+
+Find an area you can help with and do it. Open source is about collaboration and open participation. Try to make your code look like what already exists and submit a pull request. If you're looking for additional ideas, the code includes `TODO` comments for minor to major improvements. Grep is your friend.
+
+Additional tests are rewarded with an immense amount of positive karma. So is documentation.
+
+Find us:
+
+* Chat: [Gitter](https://gitter.im/grin_community/Lobby).
+* Mailing list: join the [~MimbleWimble team](https://launchpad.net/~mimblewimble) and subscribe on Launchpad.
+
+## Style Guide
+
+For info on the Grin style guide, see the [style docs](doc/style.md).
+
+Grin leverages `rustfmt` to maintain consistent formatting (and a [git commit hook](doc/style.md) to run it).

README.md

@@ -16,13 +16,11 @@ To learn more, read our [introduction to MimbleWimble and Grin](doc/intro.md).
 
 ## Status
 
-Grin is still an infant, much is left to be done and contributions are welcome (see below). Check our [mailing list archives](https://lists.launchpad.net/mimblewimble/) for the latest status.
+Grin is still an infant, much is left to be done and [contributions](CONTRIBUTING.md) are welcome (see below). Check our [mailing list archives](https://lists.launchpad.net/mimblewimble/) for the latest status.
 
 ## Contributing
 
-Find an area you can help with and do it. Open source is about collaboration and open participation. Try to make your code look like what already exists and submit a pull request. If you're looking for additional ideas, the code includes TODO comments for minor to major improvements. Grep is your friend.
+To get involved, read our [contributing docs](CONTRIBUTING.md).
-
-Additional tests are rewarded with an immense amount of positive karma. So is documentation.
 
 Find us:
 

doc/style.md

@@ -0,0 +1,38 @@
+# Grin Style Guide
+
+Grin uses [rustfmt](https://github.com/rust-lang-nursery/rustfmt) to maintain consist formatting.
+
+## Install rustfmt (nightly)
+
+Note: we assume Rust has been installed via [Rustup](https://www.rustup.rs/).
+See [build docs](./build.md) for more info.
+
+rustfmt itself requires the nightly toolchain -
+
+```
+rustup update
+rustup install nightly
+rustup run nightly cargo install rustfmt-nightly
+```
+
+## Install git pre-commit hook
+
+There is a basic git [pre-commit](../.hooks/pre-commit) hook in the repo.
+
+The pre-commit hook will not prevent commits if style issues are present but it will
+indicate any files that need formatting.
+
+To enable this create a symlink in `.git/hooks` (note the relative path) -
+
+```
+cd .git/hooks
+ln -s -f ../../.hooks/pre-commit
+```
+
+## Running rustfmt
+
+To run rustfmt against a single file in grin -
+
+```
+cargo +nightly fmt -- ./core/src/lib.rs
+```