Merge branch 'develop' into doc2

.clang-format

+# This file is used by clang-format to autoformat paddle source code
+#
+# The clang-format is part of llvm toolchain.
+# It need to install llvm and clang to format source code style.
+#
+# The basic usage is,
+#   clang-format -i -style=file PATH/TO/SOURCE/CODE
+#
+# The -style=file implicit use ".clang-format" file located in one of
+# parent directory.
+# The -i means inplace change.
+#
+# The document of clang-format is
+#   http://clang.llvm.org/docs/ClangFormat.html
+#   http://clang.llvm.org/docs/ClangFormatStyleOptions.html
+---
+Language:        Cpp
+BasedOnStyle:  Google
+IndentWidth:     2
+TabWidth:        2
+ContinuationIndentWidth: 4
+MaxEmptyLinesToKeep: 2
+AccessModifierOffset: -2  # The private/protected/public has no indent in class
+Standard:  Cpp11
+AllowAllParametersOfDeclarationOnNextLine: true
+BinPackParameters: false
+BinPackArguments: false
+...
+

.clang_format.hook

+#!/bin/bash
+
+# clang-format hook without version check
+
+clang-format $@

.pre-commit-config.yaml

@@ -25,6 +25,14 @@
         files: \.md$
     -   id: remove-tabs
         files: \.md$
+-   repo: local
+    hooks:
+    -   id: clang-format
+        name: clang-format
+        description: Format files with ClangFormat
+        entry: bash .clang_format.hook -i
+        language: system
+        files: \.(c|cc|cxx|cpp|cu|h|hpp|hxx|cuh|proto)$
 -   repo: local
     hooks:
     -   id: convert-markdown-into-html

.travis.yml

@@ -17,7 +17,7 @@ addons:
       - python-pip
       - python2.7-dev
 before_install:
-  -  pip install -U virtualenv pre-commit pip
+  -  sudo pip install -U virtualenv pre-commit pip
   -  docker pull paddlepaddle/paddle:latest
 script:
   -  .travis/precommit.sh