zephyr: zmake: add utility to compute version string

Add a function, get_version_string, which generates a version string
to be used in FRID, FWID, or in headers for the build.

The format selected was:

   LAST_COMPONENT_OF_PROJECT_DIR
   "_v"
   ZEPHYR_MAJOR_VERSION
   "."
   ZEPHYR_MINOR_VERSION
   "."
   TOTAL_COMMITS
   "_"
   VCS_HASHES

Where VCS_HASHES is the (sorted) list of modules + Zephyr OS commit
hashes, like so:

   mod1:02fd7a,mod2:b5991f,os:2c65cb

There is also an option for a "static" version, like in CrOS EC OS,
which is not affected by Git repository state.  This is useful for
comparing builds across commits.  In this case, TOTAL_COMMITS is fixed
to zero, and VCS_HASHES is set to "STATIC".

Note: This is mostly just an initial pass at the version string
format, and shouldn't be considered "final" yet.  We can make further
iterations on the format as we deem necessary.

BUG=b:184832251
BRANCH=none
TEST=unit tests

Signed-off-by: Jack Rosenthal <jrosenth@chromium.org>
Change-Id: I7560c7d677f5d5ec5cf26ff6048eea91843515c3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2857914
Reviewed-by: Jeremy Bettis <jbettis@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 75 insertions, 0 deletions

diff --git a/zephyr/zmake/zmake/version.py b/zephyr/zmake/zmake/version.py
new file mode 100644
index 0000000000..03ffada947
--- /dev/null
+++ b/zephyr/zmake/zmake/version.py
@@ -0,0 +1,75 @@
+# Copyright 2021 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import subprocess
+
+import zmake.util as util
+
+
+def _get_num_commits(repo):
+    """Get the number of commits that have been made in a Git repository.
+
+    Args:
+        repo: The path to the git repo.
+
+    Returns:
+        An integer, the number of commits that have been made.
+    """
+    result = subprocess.run(['git', '-C', repo, 'rev-list', 'HEAD', '--count'],
+                            check=True, stdout=subprocess.PIPE,
+                            encoding='utf-8')
+    return int(result.stdout)
+
+
+def _get_revision(repo):
+    """Get the index's current revision of a Git repo.
+
+    Args:
+        repo: The path to the git repo.
+
+    Returns:
+        A string, of the current revision.
+    """
+    result = subprocess.run(['git', '-C', repo, 'log', '-n1', '--format=%H'],
+                            check=True, stdout=subprocess.PIPE,
+                            encoding='utf-8')
+    return result.stdout
+
+
+def get_version_string(project, zephyr_base, modules, static=False):
+    """Get the version string associated with a build.
+
+    Args:
+        project: a zmake.project.Project object
+        zephyr_base: the path to the zephyr directory
+        modules: a dictionary mapping module names to module paths
+        static: if set, create a version string not dependent on git
+            commits, thus allowing binaries to be compared between two
+            commits.
+
+    Returns:
+        A version string which can be placed in FRID, FWID, or used in
+        the build for the OS.
+    """
+    major_version, minor_version, *_ = util.read_zephyr_version(zephyr_base)
+    project_id = project.project_dir.parts[-1]
+    num_commits = 0
+
+    if static:
+        vcs_hashes = 'STATIC'
+    else:
+        repos = {
+            'os': zephyr_base,
+            **modules,
+        }
+
+        for repo in repos.values():
+            num_commits += _get_num_commits(repo)
+
+        vcs_hashes = ','.join(
+            '{}:{}'.format(name, _get_revision(repo)[:6])
+            for name, repo in sorted(repos.items()))
+
+    return '{}_v{}.{}.{}_{}'.format(
+        project_id, major_version, minor_version, num_commits, vcs_hashes)