Allow pairs() iterator on all memory based key-value tables

why:
  Previously only available for capture recorder.

nimbus/db/core_db.nim

@@ -70,7 +70,7 @@ logScope:
 template logTxt(info: static[string]): static[string] =
  "ChainDB " & info
 
-proc itNotImplemented(db: CoreDbRef, name: string) {.used.} =
+proc itNotImplemented(db: CoreDbRef|CoreDbKvtRef, name: string) {.used.} =
  debug logTxt "iterator not implemented", dbType=db.dbType, meth=name
 
 proc tmplNotImplemented*(db: CoreDbRef, name: string) {.used.} =
@@ -136,15 +136,15 @@ template shortTimeReadOnly*(db: CoreDbRef; id: CoreDbTxID; body: untyped) =
 # ------------------------------------------------------------------------------
 
 iterator pairs*(
- db: CoreDbCaptRef;
+ db: CoreDbKvtRef;
  ): (Blob, Blob)
- {.gcsafe, raises: [RlpError].} =
- case db.parent.dbType:
- of LegacyDbMemory, LegacyDbPersistent:
- for k,v in db.LegacyCoreDbCaptRef:
+ {.gcsafe.} =
+ case db.dbType:
+ of LegacyDbMemory:
+ for k,v in db.LegacyCoreDbKvtRef:
  yield (k,v)
  else:
- db.parent.itNotImplemented "pairs/capt"
+ db.itNotImplemented "pairs/kvt"
 
 iterator pairs*(
  db: CoreDbMptRef;

nimbus/db/core_db/README.md

@@ -75,5 +75,5 @@ Usage of the replacement wrapper
  db = capture.recorder # use the recorder in place of db
  ...
 
- for key,value in capture: # process recorded data
- ...
+ for key,value in capture.recorder.kvt:
+ ... # process recorded data

nimbus/db/core_db/legacy.nim

@@ -12,16 +12,12 @@
 
 import
  std/options,
- chronicles,
  eth/[common, rlp, trie/db, trie/hexary],
  results,
  ../../constants,
  ../select_backend,
  ./base
 
-logScope:
- topics = "core_db-legacy"
-
 type
  LegacyCoreDbRef* = ref object of CoreDbRef
  backend: ChainDB
@@ -147,13 +143,6 @@ method recorder*(
  ): CoreDbRef =
  db.appDb
 
-iterator pairs*(
- db: LegacyCoreDbCaptRef;
- ): (Blob, Blob)
- {.gcsafe, raises: [RlpError].} =
- for k,v in db.recorder.pairsInMemoryDB:
- yield (k,v)
-
 # ------------------------------------------------------------------------------
 # Public key-value table methods
 # ------------------------------------------------------------------------------
@@ -189,6 +178,13 @@ method contains*(
  ): bool =
  db.db.contains key
 
+iterator pairs*(
+ db: LegacyCoreDbKvtRef;
+ ): (Blob, Blob)
+ {.gcsafe.} =
+ for k,v in db.db.pairsInMemoryDB:
+ yield (k,v)
+
 # ------------------------------------------------------------------------------
 # Public hexary trie methods
 # ------------------------------------------------------------------------------