From ff0a9a8d96ff4d4e533718aab8b18a631c1303dd Mon Sep 17 00:00:00 2001
From: Michael Goderbauer <goderbauer@google.com>
Date: Tue, 12 Sep 2017 15:42:37 -0700
Subject: [PATCH] Enforce clang-format for c-like sources on Travis (#4089)

* Enforce clang-format for c-like sources on Travis

* Edit CONTRIBUTING,md

* review feedback:

* ++

* ++

* ++
---
 .travis.yml      |  1 +
 CONTRIBUTING.md  | 12 +++++++-----
 travis/format.sh | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 5 deletions(-)
 create mode 100755 travis/format.sh

diff --git a/.travis.yml b/.travis.yml
index 1ed00e9bf13..c72c15b6a69 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,3 +6,4 @@ before_script:
 script:
   - ./travis/build.sh
   - ./travis/test.sh
+  - ./travis/format.sh
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 5466bff1c3a..d0c7030316d 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -201,11 +201,13 @@ To start working on a patch:
  * Make sure you are in the `engine/src/flutter` directory.
  * `git fetch upstream`
  * `git checkout upstream/master -b name_of_your_branch`
- * Hack away. Please peruse our
-   [style guides](https://flutter.io/style-guide/) and
-   [design principles](https://flutter.io/design-principles/) before
-   working on anything non-trivial. These guidelines are intended to
-   keep the code consistent and avoid common pitfalls.
+ * Hack away.
+   * Please peruse our [style guides](https://flutter.io/style-guide/) and
+     [design principles](https://flutter.io/design-principles/) before
+     working on anything non-trivial. These guidelines are intended to
+     keep the code consistent and avoid common pitfalls.
+   * C, C++, and Objective-C code should be formatted with `clang-format` before
+     submission (use `buildtools/<OS>/clang/bin/clang-format --style=file -i`).
  * `git commit -a -m "<your brief but informative commit message>"`
  * `git push origin name_of_your_branch`
 
diff --git a/travis/format.sh b/travis/format.sh
new file mode 100755
index 00000000000..0375cd21320
--- /dev/null
+++ b/travis/format.sh
@@ -0,0 +1,39 @@
+#!/bin/bash
+set -e
+echo "Checking formatting..."
+cd ..
+
+case "$(uname -s)" in
+  Darwin)
+    OS="mac-x64"
+    ;;
+  Linux)
+    OS="linux-x64"
+    ;;
+  *)
+    echo "Unknown operating system."
+    exit -1
+    ;;
+esac
+
+CLANG_FORMAT="buildtools/$OS/clang/bin/clang-format"
+$CLANG_FORMAT --version
+
+FILES="$(find flutter/ -name '*.cpp' -or -name '*.h' -or -name '*.c' -or -name '*.cc' -or -name '*.m' -or -name '*.mm')"
+FAILED_CHECKS=0
+
+for FILE in $FILES; do
+  set +e
+  RESULT="$(diff -u "$FILE" <($CLANG_FORMAT --style=file "$FILE"))"
+  set -e
+  if ! [ -z "$RESULT" ]; then
+    echo "$RESULT"
+    FAILED_CHECKS=$(($counter+1))
+  fi
+done
+
+if [ $FAILED_CHECKS -ne 0 ]; then
+  echo "Some files are formatted incorrectly. To fix, apply diffs from above."
+fi
+
+exit $FAILED_CHECKS