Maintain a "modifier" info for each topic/association

[jri]

For each topic/association DM should store the information which user did the most recent modification.

This is needed for #747.

[Jörg Richter <jri@…>]

In cd8f2ba70a805db88ef498140571131815ec2022/deepamehta:

Add "modifier" info to each topic/assoc (#749).

Every time a topic/association is updated DM attaches the "modifying user" (a username) to the topic/association.
So, DM can tell which user did the most recent modification on a topic/association.

Access Control API

New method:

String getModifier(DeepaMehtaObject object)

Returns the modifier of a topic or an association, or null if no modifier is set.

See #749.

[Jörg Richter <jri@…>]

In ba6821482cbbfc40cac9a202f98cc45a6d525cd5/deepamehta:

3 more Access Control calls are RESTful (#749).

GET /accesscontrol/object/{id}/creator
GET /accesscontrol/object/{id}/owner
GET /accesscontrol/object/{id}/modifier

Returns a topic's/association's creator, owner, modifier respectively.

BREAKING CHANGE

Access Control API

3 getter methods have changed signatures. Instead of an object they take a sole object ID.

String getCreator(DeepaMehtaObject object)  -> String getCreator(long objectId)
String getOwner(DeepaMehtaObject object)    -> String getOwner(long objectId)
String getModifier(DeepaMehtaObject object) -> String getModifier(long objectId)

See #749.

[Jörg Richter <jri@…>]

In 4d25473979ffeb5e778144993828858c0bf7c74f/deepamehta:

2 more Time service calls are RESTful (#749).

GET /time/object/{id}/created
GET /time/object/{id}/modified

Returns a topic's/association's creation and modification timestamps respectively.

BREAKING CHANGE

Time API

2 getter methods have changed signatures. Instead of an object they take a sole object ID.

long getCreationTime(DeepaMehtaObject object)     -> long getCreationTime(long objectId)
long getModificationTime(DeepaMehtaObject object) -> long getModificationTime(long objectId)

See #749.

[Jörg Richter <jri@…>]

In 819d1488852d8951128d74e961bd250427b2de5a/deepamehta:

Extend client-side AccsCtrl? and Time APIs (#749).

New methods:

dm4c.restc.get_creator(object_id)
dm4c.restc.get_owner(object_id)
dm4c.restc.get_modifier(object_id)

dm4c.restc.get_creation_time(object_id)
dm4c.restc.get_modification_time(object_id)

See #749.

[Jörg Richter <jri@…>]

In 4b802b15e33870e9a7e82099c5ab076784a8f5d1/deepamehta:

AcssCtrl?: set modifier user also on create (#749).

The "modifying user" (a username) is also set on topic/association creation time (besides update time).

This is analogous to the Time module which sets the modification timestamp already on creation time. (This in turn is required for the caching mechanism which expects each topic/association having a modification timestamp.)

So, when there is a modification timestamp the corresponding modifying user is supposed to be known as well.

See #749.