Add new tie breaker.

ognibuild/debian/build_deps.py

@@ -0,0 +1,65 @@
+#!/usr/bin/python3
+# Copyright (C) 2021 Jelmer Vernooij
+#
+# 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; either version 2 of the License, or
+# (at your option) any later version.
+#
+# 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
+
+"""Tie breaking by build deps."""
+
+
+class BuildDependencyTieBreaker(object):
+
+    def __init__(self, rootdir):
+        import apt_pkg
+        apt_pkg.init()
+        apt_pkg.config.set('Dir', rootdir)
+        self._apt_cache = apt_pkg.SourceRecords()
+        self._counts = None
+
+    @classmethod
+    def from_session(cls, session):
+        return cls(session.location)
+
+    def _count(self):
+        counts = {}
+        self._apt_cache.restart()
+        while self._apt_cache.step():
+            try:
+                for d in self._apt_cache.build_depends.values():
+                    for o in d:
+                        for p in o:
+                            counts.setdefault(p[0], 0)
+                            counts[p[0]] += 1
+            except AttributeError:
+                pass
+        return counts
+
+    def __call__(self, reqs):
+        if self._counts is None:
+            self._counts = self._count()
+        by_count = {}
+        for req in reqs:
+            by_count[req] = self._counts.get(list(req.package_names())[0])
+        return max(by_count.items(), key=lambda k: k[1] or 0)[0]
+
+
+if __name__ == '__main__':
+    import argparse
+    from ..resolver.apt import AptRequirement
+    parser = argparse.ArgumentParser()
+    parser.add_argument('req', nargs='+')
+    args = parser.parse_args()
+    reqs = [AptRequirement.from_str(req) for req in args.req]
+    tie_breaker = BuildDependencyTieBreaker('/')
+    print(tie_breaker(reqs))

ognibuild/resolver/apt.py

@@ -83,6 +83,9 @@ class AptRequirement(Requirement):
     def pkg_relation_str(self):
         return PkgRelation.str(self.relations)
 
+    def __hash__(self):
+        return hash((type(self), self.pkg_relation_str()))
+
     def __eq__(self, other):
         return isinstance(self, type(other)) and self.relations == other.relations