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diff --git a/git_superproject.py b/git_superproject.py
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+# Copyright (C) 2021 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Provide functionality to get all projects and their SHAs from Superproject.
+
+For more information on superproject, check out:
+https://en.wikibooks.org/wiki/Git/Submodules_and_Superprojects
+
+Examples:
+  superproject = Superproject()
+  project_shas = superproject.GetAllProjectsSHAs()
+"""
+
+import os
+import sys
+
+from error import GitError
+from git_command import GitCommand
+import platform_utils
+
+
+class Superproject(object):
+  """Get SHAs from superproject.
+
+  It does a 'git clone' of superproject and 'git ls-tree' to get list of SHAs for all projects.
+  It contains project_shas which is a dictionary with project/sha entries.
+  """
+  def __init__(self, repodir, superproject_dir='exp-superproject'):
+    """Initializes superproject.
+
+    Args:
+      repodir: Path to the .repo/ dir for holding all internal checkout state.
+      superproject_dir: Relative path under |repodir| to checkout superproject.
+    """
+    self._project_shas = None
+    self._repodir = os.path.abspath(repodir)
+    self._superproject_dir = superproject_dir
+    self._superproject_path = os.path.join(self._repodir, superproject_dir)
+
+  @property
+  def project_shas(self):
+    """Returns a dictionary of projects and their SHAs."""
+    return self._project_shas
+
+  def _Clone(self, url, branch=None):
+    """Do a 'git clone' for the given url and branch.
+
+    Args:
+      url: superproject's url to be passed to git clone.
+      branch: the branchname to be passed as argument to git clone.
+
+    Returns:
+      True if 'git clone <url> <branch>' is successful, or False.
+    """
+    cmd = ['clone', url, '--depth', '1']
+    if branch:
+      cmd += ['--branch', branch]
+    p = GitCommand(None,
+                   cmd,
+                   cwd=self._superproject_path,
+                   capture_stdout=True,
+                   capture_stderr=True)
+    retval = p.Wait()
+    if retval:
+      # `git clone` is documented to produce an exit status of `128` if
+      # the requested url or branch are not present in the configuration.
+      print('repo: error: git clone call failed with return code: %r, stderr: %r' %
+            (retval, p.stderr), file=sys.stderr)
+      return False
+    return True
+
+  def _LsTree(self):
+    """Returns the data from 'git ls-tree -r HEAD'.
+
+    Works only in git repositories.
+
+    Returns:
+      data: data returned from 'git ls-tree -r HEAD' instead of None.
+    """
+    git_dir = os.path.join(self._superproject_path, 'superproject')
+    if not os.path.exists(git_dir):
+      raise GitError('git ls-tree. Missing drectory: %s' % git_dir)
+    data = None
+    cmd = ['ls-tree', '-z', '-r', 'HEAD']
+    p = GitCommand(None,
+                   cmd,
+                   cwd=git_dir,
+                   capture_stdout=True,
+                   capture_stderr=True)
+    retval = p.Wait()
+    if retval == 0:
+      data = p.stdout
+    else:
+      # `git clone` is documented to produce an exit status of `128` if
+      # the requested url or branch are not present in the configuration.
+      print('repo: error: git ls-tree call failed with return code: %r, stderr: %r' % (
+          retval, p.stderr), file=sys.stderr)
+    return data
+
+  def GetAllProjectsSHAs(self, url, branch=None):
+    """Get SHAs for all projects from superproject and save them in _project_shas.
+
+    Args:
+      url: superproject's url to be passed to git clone.
+      branch: the branchname to be passed as argument to git clone.
+
+    Returns:
+      A dictionary with the projects/SHAs instead of None.
+    """
+    if not url:
+      raise ValueError('url argument is not supplied.')
+    if os.path.exists(self._superproject_path):
+      platform_utils.rmtree(self._superproject_path)
+    os.mkdir(self._superproject_path)
+
+    # TODO(rtenneti): we shouldn't be cloning the repo from scratch every time.
+    if not self._Clone(url, branch):
+      raise GitError('git clone failed for url: %s' % url)
+
+    data = self._LsTree()
+    if not data:
+      raise GitError('git ls-tree failed for url: %s' % url)
+
+    # Parse lines like the following to select lines starting with '160000' and
+    # build a dictionary with project path (last element) and its SHA (3rd element).
+    #
+    # 160000 commit 2c2724cb36cd5a9cec6c852c681efc3b7c6b86ea\tart\x00
+    # 120000 blob acc2cbdf438f9d2141f0ae424cec1d8fc4b5d97f\tbootstrap.bash\x00
+    shas = {}
+    for line in data.split('\x00'):
+      ls_data = line.split(None, 3)
+      if not ls_data:
+        break
+      if ls_data[0] == '160000':
+        shas[ls_data[3]] = ls_data[2]
+
+    self._project_shas = shas
+    return shas