Don't remove spent UTXOs from spendable.

Slower, yet enables getting the full history of a key's interactions.
Will be useful in the planned personal_getTransactionHistory mentioned
in #292.

Updates the broken spendable test to the latest policies. It now passes.

src/Database/Filesystem/DB/TransactionsDB.nim

@@ -362,12 +362,11 @@ proc removeFromSpendable(
     o += 33
   db.put(SPENDABLE(key), spendable)
 
-#Add the Transaction's outputs to spendable while removing spent inputs.
+#Add the Transaction's outputs to spendable.
 proc verify*(
   db: DB,
   tx: Transaction
 ) {.forceCheck: [].} =
-  #Add spendable outputs.
   if (tx of Claim) or (tx of Send):
     for o in 0 ..< tx.outputs.len:
       db.addToSpendable(
@@ -376,50 +375,19 @@ proc verify*(
         o
       )
 
-    if tx of Send:
-      #Remove spent inputs.
-      for input in tx.inputs:
-        var key: EdPublicKey
-        try:
-          key = db.loadSendOutput(cast[FundedInput](input)).key
-        except DBReadError:
-          panic("Removing a non-existent output.")
-
-        db.removeFromSpendable(
-          key,
-          input.hash,
-          cast[FundedInput](input).nonce
-        )
-
-#Add a inputs back to spendable while removing unverified outputs.
+#Removes outputs from spendable.
 proc unverify*(
   db: DB,
   tx: Transaction
 ) {.forceCheck: [].} =
   if (tx of Claim) or (tx of Send):
-    #Remove outputs.
     for o in 0 ..< tx.outputs.len:
       db.removeFromSpendable(
         cast[SendOutput](tx.outputs[o]).key,
         tx.hash,
         o
       )
 
-    #Restore inputs.
-    if tx of Send:
-      for input in tx.inputs:
-        var key: EdPublicKey
-        try:
-          key = db.loadSendOutput(cast[FundedInput](input)).key
-        except DBReadError:
-          panic("Restoring a non-existent output.")
-
-        db.addToSpendable(
-          key,
-          input.hash,
-          cast[FundedInput](input).nonce
-        )
-
 #Mark a Transaction as beaten.
 proc beat*(
   db: DB,
@@ -487,6 +455,9 @@ proc prune*(
       discard
     db.del(OUTPUT_SPENDERS(newFundedInput(hash, o)))
 
-    #If it has no spenders and is tracked by spendable, remove it.
-    if (spenders == "") and (tx.outputs[o] of SendOutput):
+    #If it is tracked by spendable, remove it.
+    #Should be handled by unverify, so I'm not really sure why this is here.
+    #That said, it doesn't hurt to have, and it's safe to run even if the outputs aren't present in spendable.
+    #-- Kayaba
+    if tx.outputs[o] of SendOutput:
       db.removeFromSpendable(cast[SendOutput](tx.outputs[o]).key, hash, o)

tests/Database/Filesystem/DB/TransactionsDB/SpendableTest.nim

@@ -88,57 +88,44 @@ suite "Spendable":
       compare()
 
       #Spend outputs.
-      var queue: seq[(EdPublicKey, FundedInput)] = @[]
       for key in spendable.keys():
         if spendable[key].len == 0:
           continue
 
         inputs = @[]
         var i: int = 0
-        while true:
+        while i != spendable[key].len:
           if rand(1) == 0:
             inputs.add(spendable[key][i])
             spendable[key].delete(i)
           else:
             inc(i)
 
-          if i == spendable[key].len:
-            break
-
         if inputs.len != 0:
           var outputKey: EdPublicKey = wallets[rand(10 - 1)].publicKey
           send = newSend(inputs, newSendOutput(outputKey, 0))
           db.save(send)
-          db.verify(send)
           sends.add(send)
-
-          queue.add((outputKey, newFundedInput(send.hash, 0)))
           spenders[send.hash.serialize() & char(0)] = outputKey
 
-      for output in queue:
-        if not spendable.hasKey(output[0]):
-          spendable[output[0]] = @[]
-        spendable[output[0]].add(output[1])
-
       compare()
 
       #Unverify a Send.
       if sends.len != 0:
         var s: int = rand(sends.high)
         db.unverify(sends[s])
-        for input in sends[s].inputs:
-          spendable[
-            spenders[input.hash.serialize() & char(cast[FundedInput](input).nonce)]
-          ].add(cast[FundedInput](input))
 
         for o1 in 0 ..< sends[s].outputs.len:
-          var output: SendOutput = cast[SendOutput](sends[s].outputs[o1])
-          for o2 in 0 ..< spendable[output.key].len:
+          var
+            output: SendOutput = cast[SendOutput](sends[s].outputs[o1])
+            o2: int = 0
+          while o2 < spendable[output.key].len:
             if (
               (spendable[output.key][o2].hash == sends[s].hash) and
               (spendable[output.key][o2].nonce == o1)
             ):
               spendable[output.key].delete(o2)
-              break
+            else:
+              inc(o2)
 
       compare()