Speed up source checks in Travis (#885)

* Factor out a whitespace checking script

* Factor out a copyright checking script

* Rewrite lint.sh to honor revision ranges

* Only restyle files that are part of the PR

* Run C++ lint before builds to fail faster

* Git grep doesn't operate on revision ranges

* style.sh accepts clang-format 6 or 7

4 files changed, 89 insertions, 5 deletions

diff --git a/scripts/check_copyright.sh b/scripts/check_copyright.sh
new file mode 100755
index 0000000..14857d3
--- /dev/null
+++ b/scripts/check_copyright.sh
@@ -0,0 +1,31 @@
+# Copyright 2018 Google
+#
+# 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.
+
+# Check source files for copyright notices
+
+options=(
+  -E  # Use extended regexps
+  -I  # Exclude binary files
+  -L  # Show files that don't have a match
+  'Copyright [0-9]{4}.*Google'
+)
+
+git grep "${options[@]}" \
+    -- '*.'{c,cc,h,m,mm,sh,swift} \
+    ':(exclude)**/third_party/**'
+if [[ $? == 0 ]]; then
+  echo "ERROR: Missing copyright notices in the files above. Please fix."
+  exit 1
+fi
+
diff --git a/scripts/check_whitespace.sh b/scripts/check_whitespace.sh
new file mode 100755
index 0000000..a38d4ce
--- /dev/null
+++ b/scripts/check_whitespace.sh
@@ -0,0 +1,33 @@
+# Copyright 2018 Google
+#
+# 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.
+
+# Fail on an trailing whitespace characters, excluding
+#   * binary files (-I)
+#   * nanopb-generated files
+#
+# Note: specifying revisions we care about makes this go slower than just
+# grepping through the whole repo.
+options=(
+  -n  # show line numbers
+  -I  # exclude binary files
+  ' $'
+)
+
+git grep "${options[@]}" \
+    -- ':(exclude)Firestore/Protos/nanopb'
+if [[ $? == 0 ]]; then
+  echo "ERROR: Trailing whitespace found in the files above. Please fix."
+  exit 1
+fi
+
diff --git a/scripts/lint.sh b/scripts/lint.sh
index 442f7f8..d0f82b1 100755
--- a/scripts/lint.sh
+++ b/scripts/lint.sh
@@ -12,7 +12,23 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-find Firestore/core \( \
-  -name \*.h -o \
-  -name \*.cc \) -print0 \
+# Lints C++ files for conformance with the Google C++ style guide
+
+options=(
+    -z    # \0 terminate output
+)
+
+if [[ $# -gt 0 ]]; then
+  # Interpret any command-line argument as a revision range
+  command=(git diff --name-only)
+  options+=("$@")
+
+else
+  # Default to operating on all files that match the pattern
+  command=(git ls-files)
+fi
+
+
+"${command[@]}" "${options[@]}" \
+    -- 'Firestore/core/**/*.'{h,cc} \
   | xargs -0 python scripts/cpplint.py --quiet
diff --git a/scripts/style.sh b/scripts/style.sh
index e2f8207..317c8c6 100755
--- a/scripts/style.sh
+++ b/scripts/style.sh
@@ -23,8 +23,12 @@
 
 system=$(uname -s)
 
-if [[ $(clang-format --version) != *"version 6"* ]]; then
-  echo "Please upgrade to clang-format version 6."
+version=$(clang-format --version)
+version="${version/*version /}"
+version="${version/.*/}"
+if [[ "$version" != 6 && "$version" != 7 ]]; then
+  # Allow an older clang-format to accommodate Travis version skew.
+  echo "Please upgrade to clang-format version 7."
   echo "If it's installed via homebrew you can run: brew upgrade clang-format"
   exit 1
 fi