More work on resolvers.

ognibuild/resolver/__init__.py

@@ -0,0 +1,76 @@
+#!/usr/bin/python3
+# Copyright (C) 2020 Jelmer Vernooij <jelmer@jelmer.uk>
+#
+# 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
+
+
+class MissingDependencies(Exception):
+
+    def __init__(self, reqs):
+        self.requirements = reqs
+
+
+class Resolver(object):
+
+    def install(self, requirements):
+        raise NotImplementedError(self.install)
+
+    def explain(self, requirements):
+        raise NotImplementedError(self.explain)
+
+
+class NativeResolver(Resolver):
+    def __init__(self, session):
+        self.session = session
+
+    @classmethod
+    def from_session(cls, session):
+        return cls(session)
+
+    def install(self, requirements):
+        raise NotImplementedError(self.install)
+
+    def explain(self, requirements):
+        raise NotImplementedError(self.explain)
+
+
+class ExplainResolver(Resolver):
+    def __init__(self, session):
+        self.session = session
+
+    @classmethod
+    def from_session(cls, session):
+        return cls(session)
+
+    def install(self, requirements):
+        raise MissingDependencies(requirements)
+
+
+class AutoResolver(Resolver):
+    """Automatically find out the most appropriate way to install dependencies.
+    """
+
+    def __init__(self, session):
+        self.session = session
+
+    @classmethod
+    def from_session(cls, session):
+        return cls(session)
+
+    def install(self, requirements):
+        raise NotImplementedError(self.install)
+
+    def explain(self, requirements):
+        raise NotImplementedError(self.explain)

ognibuild/resolver/apt.py

@@ -0,0 +1,84 @@
+#!/usr/bin/python3
+# Copyright (C) 2020 Jelmer Vernooij <jelmer@jelmer.uk>
+#
+# 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
+
+import posixpath
+
+from ..apt import AptManager
+
+from . import Resolver
+from ..requirements import (
+    BinaryRequirement,
+    PythonPackageRequirement,
+    )
+
+
+class NoAptPackage(Exception):
+    """No apt package."""
+
+
+def resolve_binary_req(apt_mgr, req):
+    if posixpath.isabs(req.binary_name):
+        paths = [req.binary_name]
+    else:
+        paths = [
+            posixpath.join(dirname, req.binary_name)
+            for dirname in ["/usr/bin", "/bin"]
+        ]
+    return apt_mgr.get_package_for_paths(paths)
+
+
+APT_REQUIREMENT_RESOLVERS = [
+    (BinaryRequirement, resolve_binary_req),
+]
+
+
+class AptResolver(Resolver):
+
+    def __init__(self, apt):
+        self.apt = apt
+
+    @classmethod
+    def from_session(cls, session):
+        return cls(AptManager(session))
+
+    def install(self, requirements):
+        missing = []
+        for req in requirements:
+            try:
+                pps = list(req.possible_paths())
+            except NotImplementedError:
+                missing.append(req)
+            else:
+                if not pps or not any(self.apt.session.exists(p) for p in pps):
+                    missing.append(req)
+        if missing:
+            self.apt.install(list(self.resolve(missing)))
+
+    def explain(self, requirements):
+        raise NotImplementedError(self.explain)
+
+    def resolve(self, requirements):
+        for req in requirements:
+            for rr_class, rr_fn in APT_REQUIREMENT_RESOLVERS:
+                if isinstance(req, rr_class):
+                    package_name = rr_fn(self.apt, req)
+                    if package_name is None:
+                        raise NoAptPackage()
+                    yield package_name
+                    break
+            else:
+                raise NotImplementedError