Check formatting in Travis

Summary:
Check code formatting before running tests. Goal is to make it easier to deal
with external pull requests.

Test Plan: See https://travis-ci.org/facebook/rocksdb/builds/80952963

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47211

.travis.yml

@@ -17,6 +17,8 @@ install:
   # Build gflags
   # TODO(noetzli): Remove when gflags available through Travis
   - pushd /tmp/ && curl -L https://github.com/gflags/gflags/archive/v2.1.2.tar.gz -o gflags.tar.gz && tar xfz gflags.tar.gz && cd gflags-2.1.2 && cmake . && make && popd
+  # Download clang-format-diff.py to check source code formatting
+  - pushd /tmp/ && curl -L http://llvm.org/svn/llvm-project/cfe/trunk/tools/clang-format/clang-format-diff.py -o clang-format-diff.py && chmod +x clang-format-diff.py && popd
 
 before_script:
   # Add gflags to include/library paths
@@ -30,7 +32,7 @@ before_script:
 
 # Lousy hack to disable use and testing of fallocate, which doesn't behave quite
 # as EnvPosixTest::AllocateTest expects within the Travis OpenVZ environment.
-script: OPT=-DTRAVIS V=1 make -j4 check && OPT=-DTRAVIS V=1 make clean jclean rocksdbjava jtest
+script: OPT=-DTRAVIS CLANG_FORMAT_DIFF=/tmp/clang-format-diff.py make format && OPT=-DTRAVIS V=1 make -j4 check && OPT=-DTRAVIS V=1 make clean jclean rocksdbjava jtest
 
 notifications:
     email:

build_tools/format-diff.sh

@@ -79,6 +79,12 @@ echo -e "Detect lines that doesn't follow the format rules:\r"
 echo "$diffs" | 
   sed -e "s/\(^-.*$\)/`echo -e \"$COLOR_RED\1$COLOR_END\"`/" |
   sed -e "s/\(^+.*$\)/`echo -e \"$COLOR_GREEN\1$COLOR_END\"`/"
+
+if [[ "$OPT" == *"-DTRAVIS"* ]]
+then
+  exit 1
+fi
+
 echo -e "Would you like to fix the format automatically (y/n): \c"
 
 # Make sure under any mode, we can read user input.