Add license checks to CI

Author: andr-dev

.github/workflows/license.sh

@@ -0,0 +1,35 @@
+LICENSE_HEADER="\
+// Copyright (C) 2025 Category Labs, Inc.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>."
+
+# Check for two newlines after the license header
+LICENSE_HEADER_LEN=$(("${#LICENSE_HEADER}" + 2))
+
+exit_code=0
+
+for file in $(git ls-files -- '*.rs' '*.h' '*.hpp' '*.c' '*.cpp'); do
+    contents=$(head -c $LICENSE_HEADER_LEN "$file")
+
+    if [ "$contents" == "$LICENSE_HEADER" ]; then
+        continue
+    fi
+
+    exit_code=$((exit_code + 1))
+
+    echo "$file" >&2
+done
+
+exit $exit_code
+

.github/workflows/license.yml

@@ -0,0 +1,20 @@
+name: License
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+  workflow_dispatch:
+  workflow_call:
+
+jobs:
+  check-license:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Check licenses
+        run: .github/workflows/license.sh
+