Merge pull request #129 from signalapp/jrose/gen_java_decl-verify

Add a --verify option to gen_java_decl.py

.github/workflows/build_and_test.yml

@@ -154,6 +154,9 @@ jobs:
     - name: Install NDK tool
       run: cargo install cargo-ndk
 
+    - name: Verify that the JNI bindings are up to date
+      run: rust/bridge/jni/bin/gen_java_decl.py --verify
+
     - name: Build libsignal-client-java
       run: ./gradlew build
       working-directory: java

java/java/src/main/java/org/signal/internal/Native.java

@@ -1,5 +1,5 @@
 //
-// Copyright (C) 2020 Signal Messenger, LLC.
+// Copyright (C) 2020-2021 Signal Messenger, LLC.
 // SPDX-License-Identifier: AGPL-3.0-only
 //
 

rust/bridge/jni/bin/Native.java.in

@@ -1,5 +1,5 @@
 //
-// Copyright (C) 2020 Signal Messenger, LLC.
+// Copyright (C) 2020-2021 Signal Messenger, LLC.
 // SPDX-License-Identifier: AGPL-3.0-only
 //
 

rust/bridge/jni/bin/gen_java_decl.py

@@ -1,15 +1,31 @@
 #!/usr/bin/env python3
 
 #
-# Copyright (C) 2020 Signal Messenger, LLC.
+# Copyright (C) 2020-2021 Signal Messenger, LLC.
 # SPDX-License-Identifier: AGPL-3.0-only
 #
 
+import difflib
 import os
 import subprocess
 import re
 import sys
 
+
+# If the command-line handling below gets any more complicated, this should be switched to argparse.
+def print_usage_and_exit():
+    print('usage: %s [--verify]' % sys.argv[0], file=sys.stderr)
+    sys.exit(2)
+
+
+mode = None
+if len(sys.argv) > 2:
+    print_usage_and_exit()
+elif len(sys.argv) == 2:
+    mode = sys.argv[1]
+    if mode != '--verify':
+        print_usage_and_exit()
+
 our_abs_dir = os.path.dirname(os.path.realpath(__file__))
 
 cbindgen = subprocess.Popen(['cbindgen'], cwd=os.path.join(our_abs_dir, '..'), stdout=subprocess.PIPE, stderr=subprocess.PIPE)
@@ -102,6 +118,17 @@ native_java = os.path.join(our_abs_dir, '../../../../java/java/src/main/java/org
 if not os.access(native_java, os.F_OK):
     raise Exception("Didn't find Native.java where it was expected")
 
-fh = open(native_java, 'w')
-fh.write(contents)
-fh.close()
+if not mode:
+    with open(native_java, 'w') as fh:
+        fh.write(contents)
+elif mode == '--verify':
+    with open(native_java) as fh:
+        current_contents = fh.readlines()
+    diff = difflib.unified_diff(current_contents, contents.splitlines(keepends=True))
+    first_line = next(diff, None)
+    if first_line:
+        sys.stdout.write(first_line)
+        sys.stdout.writelines(diff)
+        sys.exit("error: Native.java not up to date; re-run %s!" % sys.argv[0])
+else:
+    raise Exception("mode not properly validated")