Skeleton code for running the forthcoming async/await compiler on pub.

tools/create_pub_snapshot.py

Index: tools/create_pub_snapshot.py
diff --git a/tools/create_pub_snapshot.py b/tools/create_pub_snapshot.py
new file mode 100644
index 0000000000000000000000000000000000000000..d99c8bd76d0b44308a58819f5e7156625767bd58
--- /dev/null
+++ b/tools/create_pub_snapshot.py
@@ -0,0 +1,60 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2014 The Dart Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+This script runs the async/await compiler on pub and then compiles the output
+of that to a snapshot.
+
+Usage: create_pub_snapshot.py <dart> <package root> <output dir>
+
+When #104 is fixed, this script is no longer needed. Instead, replace the
+generate_pub_snapshot action in utils/pub.gyp with:
+
+    'action': [
+      '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
+      '--package-root=<(PRODUCT_DIR)/pub_packages/',
+      '--snapshot=<(SHARED_INTERMEDIATE_DIR)/pub.dart.snapshot',
+      '../../sdk/lib/_internal/pub/bin/pub.dart',
+    ]
+"""
+
+import os
+import subprocess
+import sys
+
+
+def Main():
+  if len(sys.argv) < 4:
+    raise Exception("""Not enough arguments.
+
+Usage: create_pub_snapshot.py <dart> <package root> <output file>""")
+
+  dart_path = sys.argv[1]
+  package_root = sys.argv[2]
+  output_dir = sys.argv[3]
+
+  # Run the async compiler.
+  status = subprocess.call([
+    dart_path,
+    '--package-root=' + package_root,
+    '../../sdk/lib/_internal/pub/bin/async_compile.dart',

[ricow1, 2014/08/25 06:22:03]

please add a comment about what this is relative to, or even better, pass this
in from the gyp file where it is obvious

[Bob Nystrom, 2014/08/25 17:40:00]

Done.

+    output_dir,
+    '--silent'
+  ])
+  if status != 0: return status
+
+  # Generate the snapshot from the output of that.
+  subprocess.call([

[ricow1, 2014/08/25 06:22:03]

set status = this call, otherwise the exitcode is ignored

[Bob Nystrom, 2014/08/25 17:40:00]

Oops, good catch! Fixed.

+    dart_path,
+    '--package-root=' + package_root,
+    '--snapshot=' + os.path.join(output_dir, 'pub.dart.snapshot'),
+    os.path.join(output_dir, 'pub_async/bin/pub.dart')
+  ])
+  if status != 0: return status
+
+
+if __name__ == '__main__':
+  sys.exit(Main())