Initial commit for TF-A CI scripts

Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
diff --git a/script/translate_refspec.py b/script/translate_refspec.py
new file mode 100755
index 0000000..9e6b370
--- /dev/null
+++ b/script/translate_refspec.py
@@ -0,0 +1,120 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2019, Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+# This scripts translates certain accepted refspec schemes to something that can
+# be used on git command line. For example, given the refspec 'topic:foo/bar'
+# for a given project, this script translates and prints the full commit hash.
+#
+# If a scheme is not recognized, print the received refspec unchanged.
+
+import argparse
+import gerrit
+import sys
+
+# Gerrit servers we care about.
+gerrit_arm = gerrit.GerritServer("gerrit.oss.arm.com")
+gerrit_tforg = gerrit.GerritServer("review.trustedfirmware.org")
+
+# Trusted Firmware-A and associated projects.
+# Different projects are hosted on different Gerrit servers.
+projects = {
+    # Projects hosted on Arm Gerrit server.
+    "arm": {
+        "trusted-firmware": gerrit.GerritProject("pdcs-platforms/ap/tf-topics", gerrit_arm),
+        "trusted-firmware-tf": gerrit.GerritProject("trusted-firmware/tf-a-tests", gerrit_arm),
+        "trusted-firmware-ci": gerrit.GerritProject("pdswinf/ci/pdcs-platforms/platform-ci", gerrit_arm),
+        "scp": gerrit.GerritProject("scp/firmware", gerrit_arm),
+    },
+
+    # Projects hosted on trustedfirmware.org Gerrit server.
+    "tforg": {
+        "trusted-firmware": gerrit.GerritProject("TF-A/trusted-firmware-a", gerrit_tforg),
+        "trusted-firmware-tf": gerrit.GerritProject("TF-A/tf-a-tests", gerrit_tforg),
+    },
+}
+
+# Argument setup
+parser = argparse.ArgumentParser()
+parser.add_argument("--project", "-p",
+                    help="Gerrit project identifier this refspec belongs to")
+parser.add_argument("--server", "-s", help="Gerrit server hosting this project",
+                    choices=["arm", "tforg"])
+parser.add_argument("--user", "-u",
+                    help="Username to use to query the Gerrit server")
+parser.add_argument("--key", "-k",
+                    help="SSH private key to use to authenticate with the Gerrit server")
+parser.add_argument("refspec", help="Refspec to translate")
+opts = parser.parse_args()
+
+project = projects[opts.server][opts.project]
+
+# Default action: print refspec and exit
+def do_default():
+    print(opts.refspec)
+    sys.exit(0)
+
+def print_topic_tip(query_results):
+    patchsets = []
+    parents = []
+
+    # For each change, get its most recent patchset
+    for change in query_results:
+        patchsets.append(change["patchSets"][-1])
+
+    # For each patchset, get its parent commit
+    for patchset in patchsets:
+        parents.append(patchset["parents"][0])
+
+    # If a patchset's revision is NOT in the list of parents then it should
+    # be the tip commit
+    tips = list(filter(lambda x: x["revision"] not in parents, patchsets))
+
+    # There must be only one patchset remaining, otherwise the tip is ambiguous
+    if len(tips) > 1:
+        raise Exception("{} in {} has no unique tip commit.".format(opts.refspec,
+                                                                    opts.project))
+    if len(tips) == 0:
+        raise Exception("No tip commit found for {} in {}.".format(opts.refspec,
+                                                                   opts.project))
+    # Print the reference of the topic tip patchset
+    print(tips[0]["ref"])
+
+query = ["status:open"]
+
+# If we don't understand the refspec, that's OK. We don't translate it, but
+# print it as is.
+try:
+    scheme, rest = opts.refspec.split(":")
+    if scheme == "topic":
+        query += ["topic:" + rest]
+    elif scheme == "change":
+        query += [opts.refspec]
+    else:
+        do_default()
+except:
+    do_default()
+
+changes = project.query(query, username=opts.user, keyfile=opts.key)
+
+# The last object is a summary; drop it as it's not of interest to us.
+changes.pop()
+
+if not changes:
+    raise Exception("{} for {} resolved to nothing.".format(opts.refspec,
+                                                            opts.project))
+
+if scheme == "topic":
+    if len(changes) > 1:
+       print_topic_tip(changes)
+    else:
+        print(changes[0]["currentPatchSet"]["ref"])
+elif scheme == "change":
+    if len(changes) > 1:
+        # When querying for a specific change there must be just a single result
+        raise Exception("{} for {} did not resolve uniquely.".format(opts.refspec,
+                                                                     opts.project))
+    print(changes[0]["currentPatchSet"]["revision"])