Merge "add get_rust_pkg.py" am: e95677343a

Change-Id: I3c8dc10602b695d674f76e96c24af168fde47d55

scripts/OWNERS

@@ -3,5 +3,5 @@ danalbert@google.com
 enh@google.com
 jmgao@google.com
 rprichard@google.com
-per-file cargo2android.py = chh@google.com,srhines@google.com
+per-file cargo2android.py,get_rust_pkg.py = chh@google.com,srhines@google.com
 per-file codegen = eugenesusla@google.com

scripts/get_rust_pkg.py

@@ -0,0 +1,136 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2020 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Fetch a Rust package from crates.io.
+
+Usage: get_rust_pkg.py -v syn-1.0.7
+Get the package syn-1.0.7 from crates.io and untar it into ./syn-1.0.7.
+
+Usage: get_rust_pkg.py -v -o tmp syn
+Get the latest version of package syn, say 1.0.17,
+and untar it into tmp/syn-1.0.17.
+
+This script will abort if the target directory exists.
+"""
+
+import argparse
+import json
+import os
+import re
+import shutil
+import sys
+import tarfile
+import tempfile
+import urllib.request
+
+PKG_VERSION_PATTERN = r"(.*)-([0-9]+\.[0-9]+\.[0-9]+.*)"
+
+PKG_VERSION_MATCHER = re.compile(PKG_VERSION_PATTERN)
+
+
+def parse_args():
+  """Parse main arguments."""
+  parser = argparse.ArgumentParser("get_rust_pkg")
+  parser.add_argument(
+      "-v", action="store_true", default=False,
+      help="echo executed commands")
+  parser.add_argument(
+      "-o", metavar="out_dir", default=".",
+      help="output directory")
+  parser.add_argument(
+      dest="pkg", metavar="pkg_name",
+      help="name of Rust package to be fetched from crates.io")
+  return parser.parse_args()
+
+
+def echo(args, msg):
+  if args.v:
+    print("INFO: {}".format(msg))
+
+
+def pkg_base_name(args, name):
+  """Remove version string of name."""
+  base = name
+  version = ""
+  match = PKG_VERSION_MATCHER.match(name)
+  if match is not None:
+    base = match.group(1)
+    version = match.group(2)
+  echo(args, "package base name: {}  version: {}".format(base, version))
+  return base, version
+
+
+def find_dl_path(args, name):
+  """Ask crates.io for the latest version download path."""
+  base_name, version = pkg_base_name(args, name)
+  url = "https://crates.io/api/v1/crates/{}/versions".format(base_name)
+  echo(args, "get versions at {}".format(url))
+  with urllib.request.urlopen(url) as request:
+    data = json.loads(request.read().decode())
+    versions = data["versions"]
+    # version with the largest id number is assumed to be the latest
+    last_id = 0
+    dl_path = ""
+    for v in versions:
+      if version == v["num"]:
+        dl_path = v["dl_path"]
+        break
+      if not version and int(v["id"]) > last_id:
+        last_id = int(v["id"])
+        version = v["num"]
+        dl_path = v["dl_path"]
+    if not dl_path:
+      print("ERROR: cannot find version {} of package {}"
+            .format(version, base_name))
+      sys.exit(1)
+    echo(args, "found download path for version {}".format(version))
+    return dl_path
+
+
+def fetch_pkg(args, dl_path):
+  """Fetch package from crates.io and untar it into a subdirectory."""
+  url = "https://crates.io" + dl_path
+  tmp_dir = tempfile.mkdtemp()
+  echo(args, "fetch tar file from {}".format(url))
+  tar_file, _ = urllib.request.urlretrieve(url)
+  with tarfile.open(tar_file, mode="r") as tfile:
+    echo(args, "extract tar file {} into {}".format(tar_file, tmp_dir))
+    tfile.extractall(tmp_dir)
+    files = os.listdir(tmp_dir)
+    # There should be only one directory in the tar file,
+    # but it might not be (name + "-" + version)
+    pkg_tmp_dir = os.path.join(tmp_dir, files[0])
+    echo(args, "untared package in {}".format(pkg_tmp_dir))
+    dest_dir = os.path.join(args.o, files[0])
+    if os.path.exists(dest_dir):
+      print("ERROR: do not overwrite existing {}".format(dest_dir))
+      sys.exit(1)  # leave tar_file and tmp_dir
+    else:
+      echo(args, "move {} to {}".format(pkg_tmp_dir, dest_dir))
+      shutil.move(pkg_tmp_dir, dest_dir)
+  echo(args, "delete downloaded tar file {}".format(tar_file))
+  os.remove(tar_file)
+  echo(args, "delete temp directory {}".format(tmp_dir))
+  shutil.rmtree(tmp_dir)
+  print("SUCCESS: downloaded package in {}".format(dest_dir))
+
+
+def main():
+  args = parse_args()
+  fetch_pkg(args, find_dl_path(args, args.pkg))
+
+
+if __name__ == "__main__":
+  main()