Make git_cache.py import-able.

gclient_scm.py

Index: gclient_scm.py
diff --git a/gclient_scm.py b/gclient_scm.py
index 29684f458b91b7668b90087f87aa7ca54c21e3e1..2bcae232e7e87eae995ca1965f6b01ac33eb8899 100644
--- a/gclient_scm.py
+++ b/gclient_scm.py
@@ -18,6 +18,7 @@ import urlparse
 
 import download_from_google_storage
 import gclient_utils
+import git_cache
 import scm
 import subprocess2
 
@@ -159,23 +160,18 @@ class SCMWrapper(object):
     """Attempt to determine the remote URL for this SCMWrapper."""
     # Git
     if os.path.exists(os.path.join(self.checkout_path, '.git')):
-      actual_remote_url = shlex.split(scm.GIT.Capture(
+      actual_remote_url = shlex.split(self._Capture(
           ['config', '--local', '--get-regexp', r'remote.*.url'],
           self.checkout_path))[1]
 
       # If a cache_dir is used, obtain the actual remote URL from the cache.
       if getattr(self, 'cache_dir', None):
-        try:
-          full_cache_dir = self._Run(['cache', 'exists', '--cache-dir',
-                                      self.cache_dir, self.url],
-                                     options, cwd=self._root_dir).strip()
-        except subprocess2.CalledProcessError:
-          full_cache_dir = None
-        if (full_cache_dir.replace('\\', '/') ==
+        mirror = git_cache.Mirror(self.url)
+        if (mirror.exists() and mirror.mirror_path.replace('\\', '/') ==
             actual_remote_url.replace('\\', '/')):
-          actual_remote_url = shlex.split(scm.GIT.Capture(
+          actual_remote_url = shlex.split(self._Capture(
               ['config', '--local', '--get-regexp', r'remote.*.url'],
-              os.path.join(self._root_dir, full_cache_dir)))[1]
+              cwd=mirror.mirror_path))[1]
       return actual_remote_url
 
     # Svn
@@ -206,12 +202,11 @@ class GitWrapper(SCMWrapper):
 
   cache_dir = None
 
-  def __init__(self, url=None, root_dir=None, relpath=None, out_fh=None,
-               out_cb=None):
+  def __init__(self, url=None, *args):
     """Removes 'git+' fake prefix from git URL."""
     if url.startswith('git+http://') or url.startswith('git+https://'):
       url = url[4:]
-    SCMWrapper.__init__(self, url, root_dir, relpath, out_fh, out_cb)
+    SCMWrapper.__init__(self, url, *args)
 
   @staticmethod
   def BinaryExists():
@@ -742,11 +737,11 @@ class GitWrapper(SCMWrapper):
     """
     if not self.cache_dir:
       return url
-    v = ['-v'] if options.verbose else []
-    self._Run(['cache', 'populate'] + v + ['--cache-dir', self.cache_dir, url],
-              options, cwd=self._root_dir, retry=True)
-    return self._Run(['cache', 'exists', '--cache-dir', self.cache_dir, url],
-                     options, cwd=self._root_dir, ).strip()
+    mirror = git_cache.Mirror(url)
+    mirror.unlock()

[Ryan Tseng, 2014/04/09 00:39:44]

We actually don't want to do this.  The lock is present to avoid two or more
gclient tasklets from calling populate() at the same time.

Moreover, bot_update takes care of all unlocking(), so if the repo is locked at
this point, then something is probably wrong.

[szager1, 2014/04/09 05:22:29]

OK.  I may have gone a bit overboard in adding calls to unlock().  However, I
have seen the locking code fail sporadically on Windows.

+    mirror.populate(noisy=options.verbose)

[Ryan Tseng, 2014/04/09 00:39:44]

bootstrap=True?

[szager1, 2014/04/09 05:22:29]

Done.

+    mirror.unlock()
+    return mirror.mirror_path if mirror.exists() else None
 
   def _Clone(self, revision, url, options):
     """Clone a git repository from the given URL.