depot_tools: Add git svn find-rev for safesync_url parsing (commonly LKGR link).

gclient_scm.py

Index: gclient_scm.py
diff --git a/gclient_scm.py b/gclient_scm.py
index 55aa1cca190287dd679c8ff85200c0a80e28004e..0b21dce99a5717e3ebdd3ce2474a220a9215564f 100644
--- a/gclient_scm.py
+++ b/gclient_scm.py
@@ -483,6 +483,34 @@ class GitWrapper(SCMWrapper):
       files = self._Capture(['diff', '--name-only', merge_base]).split()
       file_list.extend([os.path.join(self.checkout_path, f) for f in files])
 
+  def GetUsableRev(self, rev, options):
+    """Finds a useful revision for this repository.
+
+    If SCM is git-svn and the head revision is less than |rev|, git svn fetch
+    will be called on the source."""
+    sha1 = None
+    # As an optimization, only verify an SVN revision as [0-9]{1,6} for now to
+    # avoid making a network request.
+    if (scm.GIT.IsGitSvn(cwd=self.checkout_path) and
+        rev.isdigit() and len(rev) < 7):
+      local_head = scm.GIT.GetGitSvnHeadRev(cwd=self.checkout_path)
+      if not local_head or local_head < int(rev):
+        if options.verbose:
+          print('Running git svn fetch. This might take a while.\n')
+        scm.GIT.Capture(['svn', 'fetch'], cwd=self.checkout_path)
+      sha1 = scm.GIT.GetSha1ForSvnRev(cwd=self.checkout_path, rev=rev)
+    elif scm.GIT.IsValidRevision(cwd=self.checkout_path, rev=rev):
+      sha1 = rev
+    if not sha1:
+      raise gclient_utils.Error(
+          ( '%s is not a value hash. Safesync URLs with a git checkout\n'
+            'currently require a git-svn remote or a safesync_url that\n'
+            'provides git sha1s. Please add a git-svn remote or change\n'
+            'your safesync_url. For more info, see:\n'
+            'http://code.google.com/p/chromium/wiki/UsingNewGit'
+            '#Initial_checkout') % rev)
+    return sha1
+
   def FullUrlForRelativeUrl(self, url):
     # Strip from last '/'
     # Equivalent to unix basename
@@ -1002,6 +1030,14 @@ class SVNWrapper(SCMWrapper):
     else:
       self._RunAndGetFileList(command, options, file_list)
 
+  def GetUsableRev(self, rev, options):
+    """Verifies the validity of the revision for this repository."""
+    if not scm.SVN.IsValidRevision(url='%s@%s' % (self.url, rev)):
+      raise gclient_utils.Error(
+        ( '%s isn\'t a valid revision. Please check that your safesync_url is\n'
+          'correct.') % rev)
+    return rev
+
   def FullUrlForRelativeUrl(self, url):
     # Find the forth '/' and strip from there. A bit hackish.
     return '/'.join(self.url.split('/')[:4]) + url