Support 'git ls-tree' in local and remote repos

4 files changed, 91 insertions, 0 deletions

diff --git a/morphlib/cachedrepo.py b/morphlib/cachedrepo.py
index d7f22400..f647102f 100644
--- a/morphlib/cachedrepo.py
+++ b/morphlib/cachedrepo.py
@@ -158,6 +158,24 @@ class CachedRepo(object):
         except cliapp.AppException:
             raise CheckoutError(self, ref, target_dir)
 
+    def ls_tree(self, ref):
+        '''Return file names found in root tree. Does not recurse to subtrees.
+
+        Raises an UnresolvedNamedReferenceError if the ref is not a SHA1
+        ref. Raises an InvalidReferenceError if the SHA1 ref is not found
+        in the repository.
+
+        '''
+
+        if not self.is_valid_sha1(ref):
+            raise UnresolvedNamedReferenceError(self, ref)
+        try:
+            sha1 = self._rev_list(ref).strip()
+        except cliapp.AppException:
+            raise InvalidReferenceError(self, ref)
+
+        return self._ls_tree(sha1)
+
     def update(self):
         '''Updates the cached repository using its origin remote.
 
@@ -182,6 +200,10 @@ class CachedRepo(object):
     def _rev_list(self, ref):  # pragma: no cover
         return self._runcmd(['git', 'rev-list', '--no-walk', ref])
 
+    def _ls_tree(self, ref):  # pragma: no cover
+        result = self._runcmd(['git', 'ls-tree', '--name-only', ref])
+        return result.split('\n')
+
     def _cat_file(self, ref, filename):  # pragma: no cover
         return self._runcmd(['git', 'cat-file', 'blob',
                              '%s:%s' % (ref, filename)])
diff --git a/morphlib/cachedrepo_tests.py b/morphlib/cachedrepo_tests.py
index 2a0c2c4b..fa660010 100644
--- a/morphlib/cachedrepo_tests.py
+++ b/morphlib/cachedrepo_tests.py
@@ -79,6 +79,16 @@ class CachedRepoTests(unittest.TestCase):
             with open(os.path.join(target_dir, 'foo.morph'), 'w') as f:
                 f.write('contents of foo.morph')
 
+    def ls_tree(self, ref):
+        output = {
+            'e28a23812eadf2fce6583b8819b9c5dbd36b9fb9':
+            ['foo.morph']
+        }
+        try:
+            return output[ref]
+        except:
+            raise cliapp.AppException('git ls-tree --name-only %s' % (ref))
+
     def update_successfully(self):
         pass
 
@@ -96,6 +106,7 @@ class CachedRepoTests(unittest.TestCase):
         self.repo._cat_file = self.cat_file
         self.repo._copy_repository = self.copy_repository
         self.repo._checkout_ref = self.checkout_ref
+        self.repo._ls_tree = self.ls_tree
         self.tempdir = morphlib.tempdir.Tempdir()
 
     def tearDown(self):
@@ -177,6 +188,18 @@ class CachedRepoTests(unittest.TestCase):
                           'a4da32f5a81c8bc6d660404724cedc3bc0914a75',
                           self.tempdir.join('failed-checkout'))
 
+    def test_ls_tree_in_existing_ref(self):
+        data = self.repo.ls_tree('e28a23812eadf2fce6583b8819b9c5dbd36b9fb9')
+        self.assertEqual(data, ['foo.morph'])
+
+    def test_fail_ls_tree_in_invalid_ref(self):
+        self.assertRaises(cachedrepo.InvalidReferenceError, self.repo.ls_tree,
+                          '079bbfd447c8534e464ce5d40b80114c2022ebf4')
+
+    def test_fail_because_ls_tree_in_named_ref_is_not_allowed(self):
+        self.assertRaises(cachedrepo.UnresolvedNamedReferenceError,
+                          self.repo.ls_tree, 'master')
+
     def test_successful_update(self):
         self.repo._update = self.update_successfully
         self.repo.update()
diff --git a/morphlib/remoterepocache.py b/morphlib/remoterepocache.py
index d8526562..c40057b1 100644
--- a/morphlib/remoterepocache.py
+++ b/morphlib/remoterepocache.py
@@ -35,6 +35,13 @@ class CatFileError(cliapp.AppException):
             self, 'Failed to cat file %s in ref %s of repo %s' %
             (filename, ref, repo_name))
 
+class LsTreeError(cliapp.AppException):
+
+    def __init__(self, repo_name, ref):
+        cliapp.AppException.__init__(
+            self, 'Failed to list tree in ref %s of repo %s' %
+            (ref, repo_name))
+
 
 class RemoteRepoCache(object):
 
@@ -56,6 +63,14 @@ class RemoteRepoCache(object):
         except:
             raise CatFileError(repo_name, ref, filename)
 
+    def ls_tree(self, repo_name, ref):
+        repo_url = self._resolver.pull_url(repo_name)
+        try:
+            info = json.loads(self._ls_tree_for_repo_url(repo_url, ref))
+            return info['tree'].keys()
+        except:
+            raise LsTreeError(repo_name, ref)
+
     def _resolve_ref_for_repo_url(self, repo_url, ref):  # pragma: no cover
         data = self._make_request('sha1s?repo=%s&ref=%s' % (repo_url, ref))
         info = json.loads(data)
@@ -66,6 +81,9 @@ class RemoteRepoCache(object):
         return self._make_request(
             'files?repo=%s&ref=%s&filename=%s' % (repo_url, ref, filename))
 
+    def _ls_tree_for_repo_url(self, repo_url, ref):  # pragma: no cover
+        return self._make_request('trees?repo=%s&ref=%s' % (repo_url, ref))
+
     def _make_request(self, path):  # pragma: no cover
         server_url = self.server_url
         if not server_url.endswith('/'):
diff --git a/morphlib/remoterepocache_tests.py b/morphlib/remoterepocache_tests.py
index 6f162f7d..5ef61f48 100644
--- a/morphlib/remoterepocache_tests.py
+++ b/morphlib/remoterepocache_tests.py
@@ -14,6 +14,7 @@
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 
+import json
 import unittest
 
 import morphlib
@@ -27,6 +28,13 @@ class RemoteRepoCacheTests(unittest.TestCase):
     def _cat_file_for_repo_url(self, repo_url, sha1, filename):
         return self.files[repo_url][sha1][filename]
 
+    def _ls_tree_for_repo_url(self, repo_url, sha1):
+        return json.dumps({
+            'repo': repo_url,
+            'ref': sha1,
+            'tree': self.files[repo_url][sha1]
+        })
+
     def setUp(self):
         self.sha1s = {
             'git://gitorious.org/baserock/morph': {
@@ -50,6 +58,7 @@ class RemoteRepoCacheTests(unittest.TestCase):
             self.server_url, resolver)
         self.cache._resolve_ref_for_repo_url = self._resolve_ref_for_repo_url
         self.cache._cat_file_for_repo_url = self._cat_file_for_repo_url
+        self.cache._ls_tree_for_repo_url = self._ls_tree_for_repo_url
 
     def test_sets_server_url(self):
         self.assertEqual(self.cache.server_url, self.server_url)
@@ -103,3 +112,22 @@ class RemoteRepoCacheTests(unittest.TestCase):
                           self.cache.cat_file, 'non-existent-repo',
                           'e28a23812eadf2fce6583b8819b9c5dbd36b9fb9',
                           'some-file')
+
+    def test_ls_tree_in_existing_repo_and_ref(self):
+        content = self.cache.ls_tree(
+            'upstream:linux', 'e28a23812eadf2fce6583b8819b9c5dbd36b9fb9')
+        self.assertEqual(content, ['linux.morph'])
+
+    def test_fail_ls_tree_using_invalid_sha1(self):
+        self.assertRaises(morphlib.remoterepocache.LsTreeError,
+                          self.cache.ls_tree, 'upstream:linux', 'blablabla')
+
+    def test_fail_ls_file_in_non_existent_ref_in_existing_repo(self):
+        self.assertRaises(morphlib.remoterepocache.LsTreeError,
+                          self.cache.ls_tree, 'upstream:linux',
+                          'ecd7a325095a0d19b8c3d76f578d85b979461d41')
+
+    def test_fail_ls_tree_in_non_existent_repo(self):
+        self.assertRaises(morphlib.remoterepocache.LsTreeError,
+                          self.cache.ls_tree, 'non-existent-repo',
+                          'e28a23812eadf2fce6583b8819b9c5dbd36b9fb9')