support a graph of mappings instead of just one layer...

This isn't the most effecient for now as we generate all the
possible mappings, but it's assumed that the number of mappings
will be low for now...

ui/fixtures/cmd.mapping.json

@@ -103,5 +103,25 @@
 	"title": "just mapping lists them",
 	"cmd": [ "mapping" ],
 	"stdout_re": "^efdb5d9c-d123-4b30-aaa8-45a9ea8f6053:/.*subdir/mapa <-> ceaa4862-dd00-41ba-9787-7480ec1b2679:/.*subdir/mapb\n$"
+},
+{
+	"special": "set hostid",
+	"comment": "that a third host",
+	"hostid": "809c2a62-0df9-42a2-adae-c0a532ad860b"
+},
+{
+	"title": "that creating host c works",
+	"cmd": [ "hosts" ],
+	"format": [ "cmd" ]
+},
+{
+	"title": "that host mapping c works",
+	"cmd": [ "mapping", "--create", "mapc", "ceaa4862-dd00-41ba-9787-7480ec1b2679:{mappathb}" ],
+	"format": [ "cmd" ]
+},
+{
+	"title": "the search will pass through other mappings to get a local mapping",
+	"cmd": [ "search", "file", "+sometag=anothervalue" ],
+	"stdout_re": "mapc/text.txt\n$"
 }
 ]

ui/medashare/cli.py

@@ -647,13 +647,16 @@ class ObjectStore(object):
 		'''Returns the tuple (lclpath, hostid, rempath) for all
 		the mappings for this hostid.'''
 
+		# this is a little trick to return all possible mappings
+		# as we will have to explore all hosts that might have a
+		# mapping through us
+
 		hostid = _makeuuid(hostuuid())
 
 		sel = select(orm.MetaDataObject.data).where(
-		    orm.HostMapping.hostid == hostid,
-		    orm.HostMapping.objid == orm.MetaDataObject.uuid)
+		    orm.MetaDataObject.type == 'mapping')
 
-		res = []
+		allmappings = collections.defaultdict(lambda: [])
 		with self._ses() as session:
 			# XXX - view
 			for obj in session.scalars(sel):
@@ -661,11 +664,29 @@ class ObjectStore(object):
 				    pathlib.Path(b).resolve()))(*x.split(':',
 				    1)) for x in obj.mapping ]
 				for idx, (id, path) in enumerate(maps):
-					if hostid == id:
-						# add other to mapping
-						other = tuple(maps[(idx + 1) %
-						    2])
-						res.append((path, ) + other)
+					other = tuple(maps[(idx + 1) %
+					    2])
+					allmappings[id].append((path, ) + other)
+
+		res = set(allmappings[hostid])
+		tovisit = res.copy()
+		visited = set()
+
+		while tovisit:
+
+			lclpath, remhid, rempath = tovisit.pop()
+
+			if (remhid, rempath) in visited:
+				continue
+
+			visited.add((remhid, rempath))
+
+			addl = { (lclpath, x[1], x[2]) for x in
+			    allmappings[remhid] if x[1] != hostid }
+
+			res.update(addl)
+			tovisit.update(addl)
+
 		return res
 
 	def by_file(self, fname, types=('metadata', )):
@@ -2588,6 +2609,47 @@ class _TestCases(unittest.TestCase):
 		# and that it can be verified
 		persona.verify(mdobj)
 
+	def test_get_hostmapping(self):
+		# that an object store
+		persona = self.persona
+		objst = ObjectStore.load(self.tempdir / 'sample.data.sqlite3')
+
+		with mock.patch(__name__ + '.hostuuid') as hostidpatch:
+			# with a local host uuid
+			hid = uuid.uuid4()
+			hostidpatch.return_value = hid
+
+			host = persona.Host(name='lclhost', hostuuid=hid)
+			objst.loadobj(host)
+
+			# and two other hosts:
+			hida = uuid.uuid4()
+			hidb = uuid.uuid4()
+
+			objst.loadobj(persona.Host(name='hosta',
+			    hostuuid=hida))
+			objst.loadobj(persona.Host(name='hostb',
+			    hostuuid=hidb))
+
+			# that when a mapping from lcl to a to b exists
+			objst.loadobj(persona.Mapping(mapping=[
+			    ':'.join((str(hid), '/lclpath')) ,
+			    ':'.join((str(hida), '/patha')) ]))
+			objst.loadobj(persona.Mapping(mapping=[
+			    ':'.join((str(hida), '/patha')) ,
+			    ':'.join((str(hidb), '/pathb')) ]))
+
+			# that both a and b are included in the mappings
+			mappings = sorted(objst.get_hostmappings())
+
+			from pathlib import PosixPath
+
+			lclpath = PosixPath('/lclpath')
+			self.assertEqual(mappings, sorted([
+			    (lclpath, hida, PosixPath('/patha')),
+			    (lclpath, hidb, PosixPath('/pathb'))
+			    ]))
+
 	def test_objectstore(self):
 		persona = self.persona
 		objst = ObjectStore.load(self.tempdir / 'sample.data.sqlite3')
@@ -2797,11 +2859,17 @@ class _TestCases(unittest.TestCase):
 					mappathb = self.tempdir / 'mapb'
 					mappathb.mkdir()
 
+					mappathc = self.tempdir / 'mapc'
+					mappathc.mkdir()
+
 					filea = mappatha / 'text.txt'
 					filea.write_text('abc123\n')
 					fileb = mappathb / 'text.txt'
+					filec = mappathc / 'text.txt'
 					shutil.copyfile(filea, fileb)
 					shutil.copystat(filea, fileb)
+					shutil.copyfile(filea, filec)
+					shutil.copystat(filea, filec)
 				elif special == 'delete files':
 					for i in cmd['files']:
 						os.unlink(i)