(core) Comments

Summary:
First iteration for comments system for Grist.
- Comments are stored in a generic metatable `_grist_Cells`
- Each comment is connected to a particular cell (hence the generic name of the table)
- Access level works naturally for records stored in this table
-- User can add/read comments for cells he can see
-- User can't update/remove comments that he doesn't own, but he can delete them by removing cells (rows/columns)
-- Anonymous users can't see comments at all.
- Each comment can have replies (but replies can't have more replies)

Comments are hidden by default, they can be enabled by COMMENTS=true env variable.
Some things for follow-up
- Avatars, currently the user's profile image is not shown or retrieved from the server
- Virtual rendering for comments list in creator panel. Currently, there is a limit of 200 comments.

Test Plan: New and existing tests

Reviewers: georgegevoian, paulfitz

Reviewed By: georgegevoian

Subscribers: paulfitz

Differential Revision: https://phab.getgrist.com/D3509

sandbox/grist/docmodel.py

@@ -147,6 +147,21 @@ class MetaTableExtras(object):
       table.docmodel.setAutoRemove(rec, not rec.colRef)
 
 
+  class _grist_Cells(object):
+    def setAutoRemove(rec, table):
+      if rec.type == 1: # Cell info of type 1 == Comments
+        # Remove if discussion is removed.
+        noParent = not rec.root and not rec.parentId
+        if rec.tableRef and rec.rowId:
+          tableRef = table.docmodel.get_table(rec.tableRef.tableId)
+          row = tableRef.lookupOne(id=rec.rowId)
+        else:
+          row = False
+        # Remove if row is removed, column is removed, table is removed or all comments are removed.
+        no_cell = not rec.colRef or not rec.tableRef or not row
+        table.docmodel.setAutoRemove(rec, noParent or no_cell)
+
+
 def enhance_model(model_class):
   """
   Given a metadata model class, add all members (formula methods) to it from the same-named inner
@@ -198,6 +213,7 @@ class DocModel(object):
     self.aclResources            = self._prep_table("_grist_ACLResources")
     self.aclRules                = self._prep_table("_grist_ACLRules")
     self.filters                 = self._prep_table("_grist_Filters")
+    self.cells                   = self._prep_table("_grist_Cells")
 
   def _prep_table(self, name):
     """

sandbox/grist/migrations.py

@@ -32,7 +32,7 @@ log = logger.Logger(__name__, logger.INFO)
 # After each migration you probably should run these commands:
 # ./test/upgradeDocument public_samples/*.grist
 # UPDATE_REGRESSION_DATA=1 GREP_TESTS=DocRegressionTests ./test/testrun.sh server
-# ./test/upgradeDocument test/fixtures/docs/Hello.grist
+# ./test/upgradeDocument core/test/fixtures/docs/Hello.grist
 
 all_migrations = {}
 
@@ -1092,3 +1092,23 @@ def migration32(tdset):
   return tdset.apply_doc_actions([
     add_column('_grist_Views_section', 'rules', 'RefList:_grist_Tables_column'),
   ])
+
+@migration(schema_version=33)
+def migration33(tdset):
+  """
+  Add _grist_Cells table
+  """
+  doc_actions = [
+    actions.AddTable('_grist_Cells', [
+      schema.make_column("tableRef",       "Ref:_grist_Tables"),
+      schema.make_column("colRef",         "Ref:_grist_Tables_column"),
+      schema.make_column("rowId",          "Int"),
+      schema.make_column("root",           "Bool"),
+      schema.make_column("parentId",       "Ref:_grist_Cells"),
+      schema.make_column("type",           "Int"),
+      schema.make_column("content",        "Text"),
+      schema.make_column("userRef",        "Text"),
+    ]),
+  ]
+
+  return tdset.apply_doc_actions(doc_actions)

sandbox/grist/schema.py

@@ -15,7 +15,7 @@ import six
 
 import actions
 
-SCHEMA_VERSION = 32
+SCHEMA_VERSION = 33
 
 def make_column(col_id, col_type, formula='', isFormula=False):
   return {
@@ -317,6 +317,21 @@ def schema_create_actions():
       # Ex2: { excluded: ['apple', 'orange'] }
       make_column("filter",         "Text")
     ]),
+
+    # Additional metadata for cells
+    actions.AddTable('_grist_Cells', [
+      make_column("tableRef",       "Ref:_grist_Tables"),
+      make_column("colRef",         "Ref:_grist_Tables_column"),
+      make_column("rowId",          "Int"),
+      # Cell metadata is stored as in hierarchical structure.
+      make_column("root",           "Bool"),
+      make_column("parentId",       "Ref:_grist_Cells"),
+      # Type of information, currently we have only one type Comments (with value 1).
+      make_column("type",           "Int"),
+      # JSON representation of the metadata.
+      make_column("content",        "Text"),
+      make_column("userRef",        "Text"),
+    ]),
   ]