NOT TO COMMITTED: Update mojo sdk to rev 0018e6a91b75bcb941c867f8a7aa1753c3b53a13

third_party/mojo/src/mojo/public/tools/mojom_fetcher/mojom_fetcher.py

Index: third_party/mojo/src/mojo/public/tools/mojom_fetcher/mojom_fetcher.py
diff --git a/third_party/mojo/src/mojo/public/tools/mojom_fetcher/mojom_fetcher.py b/third_party/mojo/src/mojo/public/tools/mojom_fetcher/mojom_fetcher.py
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index 0000000000000000000000000000000000000000..b0283e36d2ba78f15ea806433d70f20b78a445fc
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+++ b/third_party/mojo/src/mojo/public/tools/mojom_fetcher/mojom_fetcher.py
@@ -0,0 +1,196 @@
+#!/usr/bin/env python
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Tool to manage external mojom interfaces."""
+
+import argparse
+import errno
+import logging
+import os
+import sys
+import urllib2
+
+# Local library
+sys.path.insert(0, os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                "pylib"))
+# Bindings library
+sys.path.insert(0, os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                "..", "bindings", "pylib"))
+# Requests library
+sys.path.insert(0, os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                "..", "..", "..", "..", "third_party",
+                                "requests", "src"))
+
+import requests
+
+from fetcher.repository import Repository
+from fetcher.dependency import Dependency
+from mojom.parse.parser import Parse, ParseError
+
+
+class UrlRewriterException(Exception):
+  """Exception when processing URL rewrite rules."""
+  pass
+
+class UrlRewriter(object):
+  """UrlRewriter rewrites URLs according to the provided mappings.
+
+  Note that mappings are not followed transitively. If mappings contains
+  {"a": "b", "b": "c"}, then UrlRewriter.rewrite("a") will return "b", not "c".
+  """
+
+  def __init__(self, mappings):
+    self._mappings = mappings
+    for target in self._mappings.values():
+      for source in self._mappings.keys():
+        if source in target or target in source:
+          raise UrlRewriterException(
+              "%s and %s share a common subpath" % (source, target))
+
+  def rewrite(self, path):
+    for origin, destination in self._mappings.items():
+      if path.startswith(origin):
+        return destination + path[len(origin):]
+    return path
+
+
+class MojomFetcher(object):
+  def __init__(self, repository, url_rewriter):
+    self._repository = repository
+    self._url_rewriter = url_rewriter
+
+  def _requests_get(self, url):
+    return requests.get(url, verify=True)
+
+  def _os_makedirs(self, dirs):
+    try:
+      os.makedirs(dirs)
+    except OSError as e:
+      # The directory may already exist, we don't care.
+      if e.errno != errno.EEXIST:
+        raise
+
+  def _open(self, f, mode="r"):
+    return open(f, mode)
+
+  def _download_dependencies(self, dependencies):
+    """Takes the list of mojom dependencies and download the external ones.
+    Returns the number of successfully downloaded dependencies."""
+
+    downloaded = 0
+    for dep in dependencies:
+      if self._maybe_download_dep(dep):
+        downloaded += 1
+    return downloaded
+
+  def _maybe_download_dep(self, dep):
+    if not dep.maybe_is_a_url():
+      return False
+
+    for candidate in dep.generate_candidate_urls():
+      url = self._url_rewriter.rewrite(candidate)
+      response = self._requests_get("https://" + url)
+      if not response.ok:
+        # If we get an error, it just mean that this candidate URL is not
+        # correct. We must try the other ones before giving up.
+        logging.debug("Error while downloading %s (%s)", candidate, url)
+        continue
+      # This is an external dependency
+      directory = os.path.dirname(candidate)
+      full_directory = os.path.join(self._repository.get_external_directory(),
+                                    directory)
+      try:
+        self._os_makedirs(full_directory)
+      except OSError as e:
+        # The directory may already exist, we don't care.
+        if e.errno != errno.EEXIST:
+          raise
+      with self._open(os.path.join(self._repository.get_external_directory(),
+                             candidate), "w") as f:
+        data = response.content
+        try:
+          Parse(data, candidate)
+        except ParseError:
+          logging.warn("File at %s is not a mojom", url)
+          break
+        f.write(data)
+      return True
+    return False
+
+  def discover(self):
+    """Discover missing .mojom dependencies and download them."""
+    while True:
+      missing_deps = self._repository.get_missing_dependencies()
+      downloaded = self._download_dependencies(missing_deps)
+      if downloaded == 0:
+        return 0
+
+  def get(self, dep):
+    dependency = Dependency(self._repository, ".", dep)
+    downloaded = self._download_dependencies([dependency])
+    if downloaded != 0:
+      return self.discover()
+    else:
+      return -1
+
+  def update(self):
+    dependencies = [Dependency(self._repository, ".", f)
+                    for f in self._repository.get_external_urls()]
+    # TODO(etiennej): We may want to suggest to the user to delete
+    # un-downloadable dependencies.
+    downloaded = self._download_dependencies(dependencies)
+    if downloaded != 0:
+      return self.discover()
+    else:
+      return -1
+
+def _main(args):
+  if args.prefix_rewrite:
+    rewrite_rules = dict([x.split(':', 1) for x in args.prefix_rewrite])
+  else:
+    rewrite_rules = {}
+  rewriter = UrlRewriter(rewrite_rules)
+  repository_path = os.path.abspath(args.repository_path)
+  repository = Repository(repository_path, args.external_dir)
+  fetcher = MojomFetcher(repository, rewriter)
+  if args.action == 'discover':
+    return fetcher.discover()
+  elif args.action == 'get':
+    return fetcher.get(args.url)
+  elif args.action == 'update':
+    return fetcher.update()
+  else:
+    logging.error("No matching action %s", args.action[0])
+    return -1
+
+def main():
+  logging.basicConfig(level=logging.ERROR)
+  parser = argparse.ArgumentParser(description='Download mojom dependencies.')
+  parser.add_argument('--repository-path', type=str, action='store',
+                      default='.', help='The path to the client repository.')
+  parser.add_argument('--external-dir', type=str, action='store',
+                      default='external',
+                      help='Directory for external interfaces')
+  parser.add_argument('--prefix-rewrite', type=str, action='append',
+                      help='If present, "origin:destination" pairs. "origin" '
+                      'prefixes will be rewritten as "destination". May be '
+                      'used several times. Rewrites are not transitive.')
+
+  subparsers = parser.add_subparsers(dest='action', help='action')
+  parser_get = subparsers.add_parser(
+      'get', help='Get the specified URL and all its transitive dependencies')
+  parser_get.add_argument('url', type=str, nargs=1,
+                      help='URL to download for get action')
+  subparsers.add_parser(
+      'discover',
+      help='Recursively discover and download new external dependencies')
+  subparsers.add_parser('update', help='Update all external dependencies')
+
+  args = parser.parse_args()
+  return _main(args)
+
+
+if __name__ == '__main__':
+  sys.exit(main())