From 70e4b2e5eb863ee417977ada45ce1c38cae8b427 Mon Sep 17 00:00:00 2001
From: Dmitriy Ryajov <dryajov@gmail.com>
Date: Tue, 5 Apr 2022 08:24:48 -0600
Subject: [PATCH] handle empty blocks (#70)

---
 dagger/stores/cachestore.nim   | 28 +++++++++++++++++++++++++---
 dagger/stores/fsstore.nim      | 27 ++++++++++++++++++++++++++-
 dagger/stores/networkstore.nim |  4 ++++
 3 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/dagger/stores/cachestore.nim b/dagger/stores/cachestore.nim
index 8f736520..ba879398 100644
--- a/dagger/stores/cachestore.nim
+++ b/dagger/stores/cachestore.nim
@@ -22,7 +22,6 @@ import pkg/questionable
 import pkg/questionable/results
 
 import ./blockstore
-import ../blocktype
 import ../chunker
 import ../errors
 
@@ -50,28 +49,40 @@ method getBlock*(
   ## Get a block from the stores
   ##
 
+  trace "Getting block from cache", cid
+  if cid.isEmpty:
+    trace "Empty block, ignoring"
+    return cid.emptyBlock.success
+
   return self.cache[cid].catch()
 
 method hasBlock*(self: CacheStore, cid: Cid): bool =
   ## check if the block exists
   ##
 
-  self.cache.contains(cid)
+  trace "Checking for block presence in cache", cid
+  if cid.isEmpty:
+    trace "Empty block, ignoring"
+    return true
+
+  cid in self.cache
 
 func putBlockSync(self: CacheStore, blk: Block): bool =
 
   let blkSize = blk.data.len # in bytes
 
   if blkSize > self.size:
+    trace "Block size is larger than cache size", blk = blkSize, cache = self.size
     return false
 
   while self.currentSize + blkSize > self.size:
     try:
       let removed = self.cache.removeLru()
       self.currentSize -= removed.data.len
-    except EmptyLruCacheError:
+    except EmptyLruCacheError as exc:
       # if the cache is empty, can't remove anything, so break and add item
       # to the cache
+      trace "Exception puting block to cache", exc = exc.msg
       break
 
   self.cache[blk.cid] = blk
@@ -83,6 +94,12 @@ method putBlock*(
   blk: Block): Future[bool] {.async.} =
   ## Put a block to the blockstore
   ##
+
+  trace "Storing block in cache", cid = blk.cid
+  if blk.isEmpty:
+    trace "Empty block, ignoring"
+    return true
+
   return self.putBlockSync(blk)
 
 method delBlock*(
@@ -91,6 +108,11 @@ method delBlock*(
   ## delete a block/s from the block store
   ##
 
+  trace "Deleting block from cache", cid
+  if cid.isEmpty:
+    trace "Empty block, ignoring"
+    return true
+
   try:
     let removed = self.cache.del(cid)
     if removed.isSome:
diff --git a/dagger/stores/fsstore.nim b/dagger/stores/fsstore.nim
index 2b125842..29027166 100644
--- a/dagger/stores/fsstore.nim
+++ b/dagger/stores/fsstore.nim
@@ -22,7 +22,6 @@ import pkg/stew/io2
 
 import ./cachestore
 import ./blockstore
-import ../blocktype
 
 export blockstore
 
@@ -44,6 +43,13 @@ method getBlock*(
   ## Get a block from the stores
   ##
 
+  if cid.isEmpty:
+    trace "Empty block, ignoring"
+    return cid.emptyBlock.success
+
+  if cid in self.cache:
+    return await self.cache.getBlock(cid)
+
   if cid notin self:
     return Block.failure("Couldn't find block in fs store")
 
@@ -64,6 +70,10 @@ method putBlock*(
   ## Put a block to the blockstore
   ##
 
+  if blk.isEmpty:
+    trace "Empty block, ignoring"
+    return true
+
   if blk.cid in self:
     return true
 
@@ -80,6 +90,9 @@ method putBlock*(
     trace "Unable to store block", path, cid = blk.cid, error
     return false
 
+  if await self.cache.putBlock(blk):
+    trace "Unable to store block in cache", cid = blk.cid
+
   return true
 
 method delBlock*(
@@ -88,6 +101,10 @@ method delBlock*(
   ## Delete a block/s from the block store
   ##
 
+  if cid.isEmpty:
+    trace "Empty block, ignoring"
+    return true
+
   let path = self.blockPath(cid)
   if (
     let res = io2.removeFile(path);
@@ -96,12 +113,20 @@ method delBlock*(
     trace "Unable to delete block", path, cid, error
     return false
 
+  if await self.cache.delBlock(cid):
+    trace "Unable to store block in cache", cid
+
   return true
 
 method hasBlock*(self: FSStore, cid: Cid): bool =
   ## Check if the block exists in the blockstore
   ##
 
+  trace "Checking for block existence", cid
+  if cid.isEmpty:
+    trace "Empty block, ignoring"
+    return true
+
   self.blockPath(cid).isFile()
 
 proc new*(
diff --git a/dagger/stores/networkstore.nim b/dagger/stores/networkstore.nim
index 0b361caa..0d2320e0 100644
--- a/dagger/stores/networkstore.nim
+++ b/dagger/stores/networkstore.nim
@@ -54,6 +54,10 @@ method getBlock*(
 method putBlock*(
   self: NetworkStore,
   blk: bt.Block): Future[bool] {.async.} =
+  ## Store block locally and notify the
+  ## network
+  ##
+
   trace "Puting block", cid = blk.cid
 
   if not (await self.localStore.putBlock(blk)):