Git hooks format (#2984)

* Git hooks format

* Update build.ps1

Co-authored-by: Allison Chou <allichou@microsoft.com>

Co-authored-by: Allison Chou <allichou@microsoft.com>

.githooks/pre-commit

@@ -0,0 +1,15 @@
+#!/bin/sh
+LC_ALL=C
+
+# Select files to format
+FILES=$(git show --name-only --pretty="")
+[ -z "$FILES" ] && exit 0
+
+# Format all selected files with dotnet-format
+echo "dotnet-format: Formatting changed source files.."
+echo "$FILES" | cat | xargs | sed -e 's/ /,/g' | xargs dotnet-format --folder . --include >/dev/null
+echo "dotnet-format: $(git diff --cached --numstat | wc -l) file(s) formatted."
+
+# Add files to staging
+echo "$FILES" | xargs git add
+exit 0

build.ps1

@@ -0,0 +1,26 @@
+# Check dotnet-format is installed or not
+$dotnetFormat = Get-Command dotnet-format -ErrorAction Ignore -CommandType Application
+
+if ($dotnetFormat)
+{
+    Write-Host -f Magenta "dotnet format tool is already installed."
+}
+else
+{
+    Write-Host -f Magenta "Installing dotnet-format tool.."
+    & dotnet tool install -g dotnet-format
+}
+
+# We need to change default git hooks directory as .git folder is not tracked. And by default hooks are stored in .git/hooks folder.
+# So we are setting git hooks default directory to .githooks, so that we can track and version the git hooks.
+& git config core.hooksPath .githooks
+
+& $PSScriptRoot\eng\common\Build.ps1 -restore -build -pack $args
+function ExitWithExitCode([int] $exitCode) {
+    if ($ci -and $prepareMachine) {
+      Stop-Processes
+    }
+    exit $exitCode
+}
+
+ExitWithExitCode $LASTEXITCODE