1 files changed, 92 insertions, 0 deletions
diff --git a/morphcacheserver/repocache.py b/morphcacheserver/repocache.py
new file mode 100644
index 0000000..49b8200
--- /dev/null
+++ b/morphcacheserver/repocache.py
@@ -0,0 +1,92 @@
+# Copyright (C) 2012  Codethink Limited
+# 
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+
+import cliapp
+import os
+import string
+
+
+class InvalidReferenceError(cliapp.AppException):
+    
+    def __init__(self, repo, ref):
+        cliapp.AppException.__init__(
+                self, 'Ref %s is an invalid reference for repo %s' %
+                (ref, repo))
+
+
+class UnresolvedNamedReferenceError(cliapp.AppException):
+
+    def __init__(self, repo, ref):
+        cliapp.AppException.__init__(
+                self, 'Ref %s is not a SHA1 ref for repo %s' %
+                (ref, repo))
+
+
+class RepoCache(object):
+    
+    def __init__(self, app, dirname):
+        self.app = app
+        self.dirname = dirname
+
+    def resolve_ref(self, repo_url, ref):
+        quoted_url = self._quote_url(repo_url)
+        repo_dir = os.path.join(self.dirname, quoted_url)
+        try:
+            refs = self._show_ref(repo_dir, ref).split('\n')
+            refs = [x.split() for x in refs if 'origin' in x]
+            return refs[0][0]
+        except cliapp.AppException:
+            pass
+        if not self._is_valid_sha1(ref):
+            raise InvalidReferenceError(repo_url, ref)
+        try:
+            return self._rev_list(ref).strip()
+        except:
+            raise InvalidReferenceError(repo_url, ref)
+
+    def cat_file(self, repo_url, ref, filename):
+        quoted_url = self._quote_url(repo_url)
+        repo_dir = os.path.join(self.dirname, quoted_url)
+
+        if not self._is_valid_sha1(ref):
+            raise UnresolvedNamedReferenceError(repo_url, ref)
+        try:
+            sha1 = self._rev_list(repo_dir, ref).strip()
+        except:
+            raise InvalidReferenceError(repo_url, ref)
+
+        return self._cat_file(repo_dir, sha1, filename)
+        
+    def _quote_url(self, url):
+        valid_chars = string.digits + string.letters + '%_'
+        transl = lambda x: x if x in valid_chars else '_'
+        return ''.join([transl(x) for x in url])
+
+    def _show_ref(self, repo_dir, ref):
+        return self.app.runcmd(['git', 'show-ref', ref], cwd=repo_dir)
+
+    def _rev_list(self, repo_dir, ref):
+        return self.app.runcmd(
+                ['git', 'rev-list', '--no-walk', ref], cwd=repo_dir)
+
+    def _cat_file(self, repo_dir, sha1, filename):
+        return self.app.runcmd(
+                ['git', 'cat-file', 'blob', '%s:%s' % (sha1, filename)],
+                cwd=repo_dir)
+
+    def _is_valid_sha1(self, ref):
+        valid_chars = 'abcdefABCDEF0123456789'
+        return len(ref) == 40 and all([x in valid_chars for x in ref])