From 6113019f158f99fd6b3cebffb0a2c343a9da3691 Mon Sep 17 00:00:00 2001
From: Emery Hemingway <ehmry@posteo.net>
Date: Mon, 18 Mar 2019 21:50:58 +0100
Subject: [PATCH] Add "contains" to store interface

---
 src/blobsets.nim            | 22 ++++++++++++----------
 src/blobsets/filestores.nim | 11 +++++++++++
 src/blobsets/httpstores.nim | 12 ++++++++++++
 3 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/src/blobsets.nim b/src/blobsets.nim
index c010fbf..2d57c32 100644
--- a/src/blobsets.nim
+++ b/src/blobsets.nim
@@ -264,6 +264,7 @@ func toCbor*(x: BlobSet): CborNode =
     assert(bitmap.getInt.uint64 == x.bitmap, $bitmap.getInt.uint64 & " != " & $x.bitmap)
     array.add bitmap
     for y in x.table:
+      assert(not y.isNil)
       array.add y.toCbor
     newCborTag(nodeTag, array)
   of coldNode:
@@ -624,20 +625,21 @@ proc commit*(store: BlobStore; bs: BlobSet): Future[BlobSet] {.async.} =
   if bs.isCold: return bs
   let tmp = BlobSet(kind: hotNode, bitmap: bs.bitmap, table: bs.table)
   for e in tmp.table.mitems:
-    if e.isHot: e = await store.commit e
+    if e.isHot:
+      let cold = await store.commit e
+      assert(not cold.isNil)
+      e = cold
   var buf = encode tmp.toCbor
-  #let
-  #  localId = blobHash(buf)
-  #echo "check if store has ", localId.toHex
-  #let
-  #  present = await store.contains(localId, metaBlob)
-  #echo "check returned ", present
-  #if not present:
-  block:
+  let
+    localId = blobHash(buf)
+    present = await store.contains(localId, metaBlob)
+  if present:
+    return BlobSet(kind: coldNode, setId: localId)
+  else:
     let stream = store.openIngestStream(size=buf.len, kind=metaBlob)
     await stream.ingest(buf)
     let (storeId, _) = await finish(stream)
-    #assert(localId == storeId)
+    assert(localId == storeId)
     return BlobSet(kind: coldNode, setId: storeId)
 
 #
diff --git a/src/blobsets/filestores.nim b/src/blobsets/filestores.nim
index e209e3c..0b35b82 100644
--- a/src/blobsets/filestores.nim
+++ b/src/blobsets/filestores.nim
@@ -129,6 +129,16 @@ proc fsOpenIngestStream(s: BlobStore; size: BiggestInt; kind: BlobKind): IngestS
     stream.leaves = newSeq[BlobId]()
   stream
 
+proc fsContains(s: BlobStore; id: BlobId; kind: BlobKind): Future[bool] =
+  var fs = FileStore(s)
+  result = newFuture[bool]("blobsets.filestores.fsContains")
+  let path = fs.root / $kind / id.toHex
+  try:
+    close(openAsync(path, fmRead))
+    result.complete(true)
+  except:
+    result.complete(false)
+
 proc newFileStore*(root: string): BlobStore =
   ## Create a new store object backed by a file-system.
   try:
@@ -136,6 +146,7 @@ proc newFileStore*(root: string): BlobStore =
     createDir(root / $metaBlob)
   except: discard
   FileStore(
+    containsImpl: fsContains,
     openBlobStreamImpl: fsOpenBlobStream,
     openIngestStreamImpl: fsOpenIngestStream,
     root: root,
diff --git a/src/blobsets/httpstores.nim b/src/blobsets/httpstores.nim
index dc09a97..b860d7c 100644
--- a/src/blobsets/httpstores.nim
+++ b/src/blobsets/httpstores.nim
@@ -113,9 +113,21 @@ proc httpCloseStore(s: BlobStore) =
   var s = HttpStore(s)
   close s.client
 
+proc httpContains(s: BlobStore; id: BlobId; kind: BlobKind): Future[bool] {.async.} =
+  var s = HttpStore(s)
+  try:
+    let
+      url = $((s.url / $kind) / id.toHex)
+      resp = await s.client.request(url, HttpHEAD)
+    return (resp.code in {Http200, Http204})
+  except:
+    close s.client
+    return false
+
 proc newHttpStore*(url: string): HttpStore =
   HttpStore(
     closeImpl: httpCloseStore,
+    containsImpl: httpContains,
     openBlobStreamImpl: httpOpenBlobStream,
     openIngestStreamImpl: httpOpenIngestStream,
     client: newAsyncHttpClient(),