Add formatting job on CI (#3420)

Add formatting job on CI

.ci/azure-pipelines/formatting.yml

@@ -0,0 +1,31 @@
+resources:
+  containers:
+    - container: fmt
+      image: pointcloudlibrary/fmt
+
+jobs:
+  - job: formatting
+    displayName: Check code formatting
+    pool:
+      vmImage: 'Ubuntu 16.04'
+    container: fmt
+    steps:
+      - script: ./.dev/format.sh $(which clang-format-8) .
+        displayName: 'Run clang-format'
+      - script: git diff > formatting.patch
+        displayName: 'Compute diff'
+      - script: cat formatting.patch
+        displayName: 'Show diff'
+      - task: CopyFiles@2
+        inputs:
+          sourceFolder: '$(Build.SourcesDirectory)'
+          contents: 'formatting.patch'
+          targetFolder: '$(Build.ArtifactStagingDirectory)'
+        displayName: 'Copy diff to staging directory'
+      - task: PublishBuildArtifacts@1
+        inputs:
+          pathtoPublish: '$(Build.ArtifactStagingDirectory)'
+          artifactName: formatting
+        displayName: 'Publish diff'
+      - script: "[ ! -s formatting.patch ]"
+        displayName: 'Set job exit status'

.dev/format.sh

@@ -8,7 +8,7 @@
 
 format() {
     # don't use a directory with whitespace
-    local whitelist="2d cuda gpu ml simulation stereo tracking"
+    local whitelist="2d ml simulation stereo"
 
     local PCL_DIR="${2}"
     local formatter="${1}"

cmake/clang-format.cmake

@@ -1,4 +1,4 @@
-find_package(ClangFormat 6)
+find_package(ClangFormat 7)
 # search for version number in clang-format without version number
 if(ClangFormat_FOUND)
   message(STATUS "Adding target 'format'")