bitbake: tinfoil/data_smart: Allow variable history emit() to function remotely

We can't access the emit() function of varhistory currently as the datastore parameter
isn't handled correctly, nor is the output stream. Add a custom wrapper for this
function which handles the two details correctly.

(Bitbake rev: ba0fa084ccd2b1ade96425d158fd31e49e42f286)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/command.py

@@ -20,6 +20,7 @@ Commands are queued in a CommandQueue
 
 from collections import OrderedDict, defaultdict
 
+import io
 import bb.event
 import bb.cooker
 import bb.remotedata
@@ -500,6 +501,17 @@ class CommandsSync:
         d = command.remotedatastores[dsindex].varhistory
         return getattr(d, method)(*args, **kwargs)
 
+    def dataStoreConnectorVarHistCmdEmit(self, command, params):
+        dsindex = params[0]
+        var = params[1]
+        oval = params[2]
+        val = params[3]
+        d = command.remotedatastores[params[4]]
+
+        o = io.StringIO()
+        command.remotedatastores[dsindex].varhistory.emit(var, oval, val, o, d)
+        return o.getvalue()
+
     def dataStoreConnectorIncHistCmd(self, command, params):
         dsindex = params[0]
         method = params[1]