add a partial Python implementation of the backend

pylib/anki/collection.py

@@ -16,7 +16,6 @@ from typing import Any, Dict, Iterable, List, Optional, Tuple, Union
 import anki.find
 import anki.latex  # sets up hook
 import anki.template
-from anki.backend import Backend
 from anki.cards import Card
 from anki.consts import *
 from anki.db import DB
@@ -27,6 +26,7 @@ from anki.lang import _, ngettext
 from anki.media import MediaManager
 from anki.models import ModelManager
 from anki.notes import Note
+from anki.rsbackend import RustBackend
 from anki.sched import Scheduler as V1Scheduler
 from anki.schedv2 import Scheduler as V2Scheduler
 from anki.sound import stripSounds
@@ -75,12 +75,12 @@ class _Collection:
     ls: int
     conf: Dict[str, Any]
     _undo: List[Any]
-    backend: Backend
+    backend: RustBackend
 
     def __init__(
         self,
         db: DB,
-        backend: Backend,
+        backend: RustBackend,
         server: Optional["anki.storage.ServerData"] = None,
         log: bool = False,
     ) -> None:

pylib/anki/pybackend.py

@@ -0,0 +1,82 @@
+# Copyright: Ankitects Pty Ltd and contributors
+# License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
+
+"""
+A Python implementation of some backend commands.
+
+Unimplemented commands will be forwarded on to the Rust backend.
+"""
+
+from typing import Tuple, Any, Dict
+
+import anki  # pylint: disable=unused-import
+import anki.backend_pb2 as pb
+
+
+class PythonBackend:
+    def __init__(self, col: "anki.storage._Collection"):
+        self.col = col
+
+    def run_command_bytes(self, input: bytes) -> bytes:
+        pb_input = pb.BackendInput()
+        pb_input.ParseFromString(input)
+
+        pb_output = self.run_command(pb_input)
+
+        output = pb_output.SerializeToString()
+        return output
+
+    def run_command(self, input: pb.BackendInput) -> pb.BackendOutput:
+        kind = input.WhichOneof("value")
+        handler = getattr(self, kind, None)
+        # run the equivalent of the following, based on available method names
+        # if kind == "deck_tree":
+        #     return pb.BackendOutput(deck_tree=self.deck_tree(input.deck_tree))
+        if handler is not None:
+            input_variant = getattr(input, kind)
+            output_variant = handler(input_variant)
+            output_args: Dict[str, Any] = {kind: output_variant}
+            output = pb.BackendOutput(**output_args)
+            return output
+        else:
+            # forward any unknown commands onto the Rust backend
+            return self.col.backend._run_command(input)
+
+    def deck_tree(self, _input: pb.Empty) -> pb.DeckTreeOut:
+        native = self.col.sched.deckDueTree()
+        return native_deck_tree_to_proto(native)
+
+    def find_cards(self, input: pb.FindCardsIn) -> pb.FindCardsOut:
+        cids = self.col.findCards(input.search)
+        return pb.FindCardsOut(card_ids=cids)
+
+    def browser_rows(self, input: pb.BrowserRowsIn) -> pb.BrowserRowsOut:
+        sort_fields = []
+        for cid in input.card_ids:
+            sort_fields.append(
+                self.col.db.scalar(
+                    "select sfld from notes n,cards c where n.id=c.nid and c.id=?", cid
+                )
+            )
+        return pb.BrowserRowsOut(sort_fields=sort_fields)
+
+
+def native_deck_tree_to_proto(native):
+    top = pb.DeckTreeNode(children=[native_deck_node_to_proto(c) for c in native])
+    out = pb.DeckTreeOut(top=top)
+    return out
+
+
+def native_deck_node_to_proto(native: Tuple) -> pb.DeckTreeNode:
+    return pb.DeckTreeNode(
+        # fixme: need to decide whether full list
+        # should be included or just tail element
+        names=[native[0]],
+        deck_id=native[1],
+        review_count=native[2],
+        learn_count=native[3],
+        new_count=native[4],
+        children=[native_deck_node_to_proto(c) for c in native[5]],
+        # fixme: currently hard-coded
+        collapsed=False,
+    )

pylib/anki/rsbackend.py

@@ -1,3 +1,5 @@
+# Copyright: Ankitects Pty Ltd and contributors
+# License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 # pylint: skip-file
 
 from typing import Dict, List
@@ -44,7 +46,7 @@ def proto_template_reqs_to_legacy(
     return legacy_reqs
 
 
-class Backend:
+class RustBackend:
     def __init__(self, path: str):
         self._backend = ankirspy.Backend(path)
 

pylib/anki/schedv2.py

@@ -12,11 +12,11 @@ from operator import itemgetter
 from typing import Any, Callable, Dict, List, Optional, Set, Tuple, Union
 
 import anki  # pylint: disable=unused-import
-from anki.backend import SchedTimingToday
 from anki.cards import Card
 from anki.consts import *
 from anki.hooks import runHook
 from anki.lang import _
+from anki.rsbackend import SchedTimingToday
 from anki.utils import fmtTimeSpan, ids2str, intTime
 
 # card types: 0=new, 1=lrn, 2=rev, 3=relrn

pylib/anki/storage.py

@@ -7,11 +7,11 @@ import os
 import re
 from typing import Any, Dict, Optional, Tuple
 
-from anki.backend import Backend
 from anki.collection import _Collection
 from anki.consts import *
 from anki.db import DB
 from anki.lang import _
+from anki.rsbackend import RustBackend
 from anki.stdmodels import (
     addBasicModel,
     addBasicTypingModel,
@@ -30,7 +30,7 @@ def Collection(
     path: str, lock: bool = True, server: Optional[ServerData] = None, log: bool = False
 ) -> _Collection:
     "Open a new or existing collection. Path must be unicode."
-    backend = Backend(path)
+    backend = RustBackend(path)
     # fixme: this call is temporarily here to ensure the brige is working
     # on all platforms, and should be removed in a future beta
     assert backend.plus_one(5) == 6