From c6064d90df0c8a228b1305e8519d8ef56cdf95af Mon Sep 17 00:00:00 2001
From: Shae Erisson <shae@scannedinavian.com>
Date: Wed, 31 May 2023 11:04:05 -0500
Subject: [PATCH] wip changes, does not compile
---
src/Tahoe/Download.hs | 49 +++++++++++++++++++++++++++++++++++++++----
1 file changed, 45 insertions(+), 4 deletions(-)
diff --git a/src/Tahoe/Download.hs b/src/Tahoe/Download.hs
index 9674409..f82b072 100644
--- a/src/Tahoe/Download.hs
+++ b/src/Tahoe/Download.hs
@@ -1,3 +1,6 @@
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FunctionalDependencies #-}
+
{- | A high-level interface to downloading share data as bytes from storage
servers.
-}
@@ -24,6 +27,7 @@ import qualified Data.Set as Set
import Tahoe.Announcement (StorageServerAnnouncement)
import qualified Tahoe.CHK
import Tahoe.CHK.Capability (Reader (..), Verifier (..))
+import qualified Tahoe.CHK.Capability as CHK
import qualified Tahoe.CHK.Encrypt
import Tahoe.CHK.Server (StorageServer (..), StorageServerID)
import Tahoe.CHK.Types (ShareNum, StorageIndex)
@@ -44,20 +48,23 @@ type Share = (ShareNum, LB.ByteString)
given servers, if possible.
-}
download ::
- MonadIO m =>
+ (MonadIO m, Verifiable v, Readable r v) =>
-- | Information about the servers from which to consider downloading shares
-- representing the application data.
Map.Map StorageServerID StorageServerAnnouncement ->
-- | The read capability for the application data.
- Reader ->
+ r ->
-- | Get functions for interacting with a server given its URL.
LookupServer m ->
-- | Either a description of how the recovery failed or the recovered
-- application data.
m (Either DownloadError LB.ByteString)
-download servers cap@Reader{verifier = Verifier{..}} lookupServer = do
+download servers cap lookupServer = do
print' ("Going to download: " <> show storageIndex)
- locationE <- locateShares servers lookupServer storageIndex required
+ let verifier = getVerifiable cap
+ let storageIndex = getStorageIndex verifier
+ (required, _) <- getRequiredTotal ss verifier
+ locationE <- locateShares servers lookupServer storageIndex (fromIntegral required)
print' "Finished locating shares"
case locationE of
Left err -> do
@@ -72,6 +79,40 @@ download servers cap@Reader{verifier = Verifier{..}} lookupServer = do
print' "Decoded them"
pure s
+-- fetchRequiredTotal :: [StorageServerAnnouncement] -> (StorageServerAnnouncement -> IO (Either LookupError StorageServer) -> (StorageServer -> IO (Int, Int)) -> IO (Int, Int)
+-- fetchRequiredTotal locations f = _
+
+firstStorageServer :: [StorageServerAnnouncement] -> (StorageServerAnnouncement -> IO (Either LookupError StorageServer)) -> IO [StorageServer]
+firstStorageServer servers finder = do
+ responses <- mapM finder servers
+ pure $ take 1 $ rights responses
+
+{-
+ getShareNumbers :: server -> storageIndex -> IO [ShareNumber]
+ for mutables, that's getMutableShareNumbers
+ getEncodingParameters :: Capability -> StorageServer -> IO (n,k)
+ it's pure for CHK (immutables), but must be requested from the server for mutables
+ this returns the FEC encoding values so you know when to stop fetching shares
+ getStorageIndex :: Capability -> StorageIndex
+ -}
+class Verifiable v where
+ getShareNumbers :: v -> StorageServer -> IO (Set.Set ShareNum)
+ getRequiredTotal :: v -> StorageServer -> IO (Int, Int)
+ getStorageIndex :: v -> StorageIndex
+
+instance Verifiable CHK.Verifier where
+ getShareNumbers v s = storageServerGetBuckets s (storageIndex v)
+ getStorageIndex Verifier{storageIndex} = storageIndex
+
+ -- CHK is pure, we don't have to ask the StorageServer
+ getRequiredTotal Verifier{required, total} _ = pure (fromIntegral required, fromIntegral total)
+
+class Verifiable v => Readable r v | r -> v where
+ getVerifiable :: r -> v
+
+instance Readable CHK.Reader CHK.Verifier where
+ getVerifiable = verifier
+
{- | Execute each download task sequentially and return only the successful
results.
-}
--
GitLab