Protected manifest (#69)

* add protected manifes type

* encode protected manifest

* add empty block type handling

* add tests for protected manifest

dagger/blocktype.nim

@@ -7,6 +7,9 @@
 ## This file may not be copied, modified, or distributed except according to
 ## those terms.
 
+import std/tables
+export tables
+
 import pkg/upraises
 
 push: {.upraises: [].}
@@ -18,14 +21,100 @@ import pkg/questionable/results
 
 import ./errors
 
+template EmptyCid*: untyped =
+  var
+    emptyCid {.global, threadvar.}:
+      array[CIDv0..CIDv1, Table[MultiCodec, Cid]]
+
+  once:
+    emptyCid = [
+      CIDv0: {
+        multiCodec("sha2-256"): Cid
+        .init("QmdfTbBqBPQ7VNxZEYEj14VmRuZBkqFbiwReogJgS1zR1n")
+        .get()
+      }.toTable,
+      CIDv1: {
+        multiCodec("sha2-256"): Cid
+        .init("bafybeihdwdcefgh4dqkjv67uzcmw7ojee6xedzdetojuzjevtenxquvyku")
+        .get()
+      }.toTable,
+    ]
+
+  emptyCid
+
+template EmptyDigests*: untyped =
+  var
+    emptyDigests {.global, threadvar.}:
+      array[CIDv0..CIDv1, Table[MultiCodec, MultiHash]]
+
+  once:
+    emptyDigests = [
+      CIDv0: {
+        multiCodec("sha2-256"): EmptyCid[CIDv0]
+        .catch
+        .get()[multiCodec("sha2-256")]
+        .catch
+        .get()
+        .mhash
+        .get()
+      }.toTable,
+      CIDv1: {
+        multiCodec("sha2-256"): EmptyCid[CIDv0]
+        .catch
+        .get()[multiCodec("sha2-256")]
+        .catch
+        .get()
+        .mhash
+        .get()
+      }.toTable,
+    ]
+
+  emptyDigests
+
+template EmptyBlock*: untyped =
+  var
+    emptyBlock {.global, threadvar.}:
+      array[CIDv0..CIDv1, Table[MultiCodec, Block]]
+
+  once:
+    emptyBlock = [
+      CIDv0: {
+        multiCodec("sha2-256"): Block(
+          cid: EmptyCid[CIDv1][multiCodec("sha2-256")])
+      }.toTable,
+      CIDv1: {
+        multiCodec("sha2-256"): Block(
+          cid: EmptyCid[CIDv1][multiCodec("sha2-256")])
+      }.toTable,
+    ]
+
+  emptyBlock
+
 const
-  BlockSize* = 31 * 64 * 4 # file chunk read size
+  BlockSize* = 31 * 64 * 4 # block size
 
 type
   Block* = ref object of RootObj
     cid*: Cid
     data*: seq[byte]
 
+proc isEmpty*(cid: Cid): bool =
+  cid == EmptyCid[cid.cidver]
+  .catch
+  .get()[cid.mhash.get().mcodec]
+  .catch
+  .get()
+
+proc isEmpty*(blk: Block): bool =
+  blk.cid.isEmpty
+
+proc emptyBlock*(cid: Cid): Block =
+  EmptyBlock[cid.cidver]
+  .catch
+  .get()[cid.mhash.get().mcodec]
+  .catch
+  .get()
+
 proc `$`*(b: Block): string =
   result &= "cid: " & $b.cid
   result &= "\ndata: " & string.fromBytes(b.data)
@@ -62,6 +151,6 @@ func new*(
       mcodec = mhash.mcodec)
 
   if verify and cid != b.cid:
-    return "Cid's don't match!".failure
+    return "Cid and content don't match!".failure
 
   success b

dagger/manifest/coders.nim

@@ -52,10 +52,17 @@ func encode*(_: DagPBCoder, manifest: Manifest): ?!seq[byte] =
   # contains the following protobuf `Message`
   #
   # ```protobuf
+  #   Message ErasureInfo {
+  #     optional uint32 K = 1;          # number of encoded blocks
+  #     optional uint32 M = 2;          # number of parity blocks
+  #     optional bytes cid = 3;         # cid of the original dataset
+  #     optional uint32 original = 4;   # number of original blocks
+  #   }
   #   Message Header {
   #     optional bytes rootHash = 1;      # the root (tree) hash
   #     optional uint32 blockSize = 2;    # size of a single block
   #     optional uint32 blocksLen = 3;    # total amount of blocks
+  #     optional ErasureInfo erasure = 4; # erasure coding info
   #   }
   # ```
   #
@@ -65,8 +72,17 @@ func encode*(_: DagPBCoder, manifest: Manifest): ?!seq[byte] =
   header.write(1, cid.data.buffer)
   header.write(2, manifest.blockSize.uint32)
   header.write(3, manifest.len.uint32)
+  if manifest.protected:
+    var erasureInfo = initProtoBuffer()
+    erasureInfo.write(1, manifest.K.uint32)
+    erasureInfo.write(2, manifest.M.uint32)
+    erasureInfo.write(3, manifest.originalCid.data.buffer)
+    erasureInfo.write(4, manifest.originalLen.uint32)
+    erasureInfo.finish()
 
-  pbNode.write(1, header.buffer) # set the rootHash Cid as the data field
+    header.write(4, erasureInfo)
+
+  pbNode.write(1, header) # set the rootHash Cid as the data field
   pbNode.finish()
 
   return pbNode.buffer.success
@@ -78,9 +94,13 @@ func decode*(_: DagPBCoder, data: openArray[byte]): ?!Manifest =
   var
     pbNode = initProtoBuffer(data)
     pbHeader: ProtoBuffer
+    pbErasureInfo: ProtoBuffer
     rootHash: seq[byte]
+    originalCid: seq[byte]
     blockSize: uint32
     blocksLen: uint32
+    originalLen: uint32
+    K, M: uint32
     blocks: seq[Cid]
 
   # Decode `Header` message
@@ -97,6 +117,22 @@ func decode*(_: DagPBCoder, data: openArray[byte]): ?!Manifest =
   if pbHeader.getField(3, blocksLen).isErr:
     return failure("Unable to decode `blocksLen` from manifest!")
 
+  if pbHeader.getField(4, pbErasureInfo).isErr:
+    return failure("Unable to decode `erasureInfo` from manifest!")
+
+  if pbErasureInfo.buffer.len > 0:
+    if pbErasureInfo.getField(1, K).isErr:
+      return failure("Unable to decode `K` from manifest!")
+
+    if pbErasureInfo.getField(2, M).isErr:
+      return failure("Unable to decode `M` from manifest!")
+
+    if pbErasureInfo.getField(3, originalCid).isErr:
+      return failure("Unable to decode `originalCid` from manifest!")
+
+    if pbErasureInfo.getField(4, originalLen).isErr:
+      return failure("Unable to decode `originalLen` from manifest!")
+
   let rootHashCid = ? Cid.init(rootHash).mapFailure
   var linksBuf: seq[seq[byte]]
   if pbNode.getRepeatedField(2, linksBuf).isOk:
@@ -112,15 +148,27 @@ func decode*(_: DagPBCoder, data: openArray[byte]): ?!Manifest =
   if blocksLen.int != blocks.len:
     return failure("Total blocks and length of blocks in header don't match!")
 
-  Manifest(
+  var
+    self = Manifest(
       rootHash: rootHashCid.some,
       blockSize: blockSize.int,
       blocks: blocks,
       hcodec: (? rootHashCid.mhash.mapFailure).mcodec,
       codec: rootHashCid.mcodec,
-    version: rootHashCid.cidver).success
+      version: rootHashCid.cidver,
+      protected: pbErasureInfo.buffer.len > 0)
 
-proc encode*(self: var Manifest, encoder = ManifestContainers[$DagPBCodec]): ?!seq[byte] =
+  if self.protected:
+    self.K = K.int
+    self.M = M.int
+    self.originalCid = ? Cid.init(originalCid).mapFailure
+    self.originalLen = originalLen.int
+
+  self.success
+
+proc encode*(
+  self: Manifest,
+  encoder = ManifestContainers[$DagPBCodec]): ?!seq[byte] =
   ## Encode a manifest using `encoder`
   ##
 

dagger/manifest/manifest.nim

@@ -11,7 +11,6 @@ import pkg/upraises
 
 push: {.upraises: [].}
 
-import std/tables
 import pkg/libp2p/protobuf/minprotobuf
 import pkg/libp2p
 import pkg/questionable
@@ -21,31 +20,6 @@ import pkg/chronicles
 import ../errors
 import ../blocktype
 
-template EmptyDigests: untyped =
-  var
-    emptyDigests {.global, threadvar.}:
-      array[CIDv0..CIDv1, Table[MultiCodec, MultiHash]]
-
-  once:
-    emptyDigests = [
-      CIDv0: {
-        multiCodec("sha2-256"): Cid
-        .init("bafybeihdwdcefgh4dqkjv67uzcmw7ojee6xedzdetojuzjevtenxquvyku")
-        .get()
-        .mhash
-        .get()
-      }.toTable,
-      CIDv1: {
-        multiCodec("sha2-256"): Cid
-        .init("QmdfTbBqBPQ7VNxZEYEj14VmRuZBkqFbiwReogJgS1zR1n")
-        .get()
-        .mhash
-        .get()
-      }.toTable,
-    ]
-
-  emptyDigests
-
 type
   Manifest* = ref object of RootObj
     rootHash*: ?Cid         # root (tree) hash of the contained data set
@@ -54,6 +28,14 @@ type
     version*: CidVersion    # Cid version
     hcodec*: MultiCodec     # Multihash codec
     codec*: MultiCodec      # Data set codec
+    case protected*: bool   # Protected datasets have erasure coded info
+    of true:
+      K*: int               # Number of blocks to encode
+      M*: int               # Number of resulting parity blocks
+      originalCid*: Cid     # The original Cid of the dataset being erasure coded
+      originalLen*: int     # The length of the original manifest
+    else:
+      discard
 
 func len*(self: Manifest): int =
   self.blocks.len
@@ -84,6 +66,10 @@ iterator items*(self: Manifest): Cid =
   for b in self.blocks:
     yield b
 
+iterator pairs*(self: Manifest): tuple[key: int, val: Cid] =
+  for pair in self.blocks.pairs():
+    yield pair
+
 func contains*(self: Manifest, cid: Cid): bool =
   cid in self.blocks
 
@@ -122,7 +108,16 @@ proc makeRoot*(self: Manifest): ?!void =
 
     self.rootHash = cid.some
 
-  ok()
+  success()
+
+func rounded*(self: Manifest): int =
+  if (self.originalLen mod self.K) != 0:
+    return self.originalLen + (self.K - (self.originalLen mod self.K))
+
+  self.originalLen
+
+func steps*(self: Manifest): int =
+  self.rounded div self.K # number of blocks per row
 
 proc cid*(self: Manifest): ?!Cid =
   ## Generate a root hash using the treehash algorithm
@@ -136,6 +131,7 @@ proc cid*(self: Manifest): ?!Cid =
 proc new*(
   T: type Manifest,
   blocks: openArray[Cid] = [],
+  protected = false,
   version = CIDv1,
   hcodec = multiCodec("sha2-256"),
   codec = multiCodec("raw"),
@@ -151,8 +147,45 @@ proc new*(
     version: version,
     codec: codec,
     hcodec: hcodec,
-    blockSize: blockSize
+    blockSize: blockSize,
-    ).success
+    protected: protected).success
+
+proc new*(
+  T: type Manifest,
+  manifest: Manifest,
+  K, M: int): ?!Manifest =
+  ## Create an erasure protected dataset from an
+  ## un-protected one
+  ##
+
+  var
+    self = Manifest(
+      version: manifest.version,
+      codec: manifest.codec,
+      hcodec: manifest.hcodec,
+      blockSize: manifest.blockSize,
+      protected: true,
+      K: K, M: M,
+      originalCid: ? manifest.cid,
+      originalLen: manifest.len)
+
+  let
+    encodedLen = self.rounded + (self.steps * M)
+
+  self.blocks = newSeq[Cid](encodedLen)
+
+  # copy original manifest blocks
+  for i in 0..<self.rounded:
+    if i < manifest.len:
+      self.blocks[i] = manifest[i]
+    else:
+      self.blocks[i] = EmptyCid[manifest.version]
+      .catch
+      .get()[manifest.hcodec]
+      .catch
+      .get()
+
+  self.success
 
 proc new*(
   T: type Manifest,

tests/dagger/testmanifest.nim

@@ -27,17 +27,18 @@ suite "Manifest":
           ]).tryGet()
 
     let
-      checksum = @[18.byte, 32, 227, 176, 196, 66, 152,
+      encoded = @[byte 18, 32, 227, 176, 196, 66, 152,
                   252, 28, 20, 154, 251, 244, 200, 153,
                   111, 185, 36, 39, 174, 65, 228, 100,
                   155, 147, 76, 164, 149, 153, 27, 120,
                   82, 184, 85]
 
     var mh: MultiHash
-    check MultiHash.decode(checksum, mh).tryGet() > 0
+    check MultiHash.decode(encoded, mh).tryGet() > 0
 
-    let checkSumCid = Cid.init(manifest.version, manifest.codec, mh).tryGet()
+    let encodedCid = Cid.init(manifest.version, manifest.codec, mh).tryGet()
-    check checkSumCid == manifest.cid.tryGet()
+    check:
+      encodedCid == manifest.cid.tryGet()
 
   test "Should encode/decode to/from manifest":
     let
@@ -46,10 +47,51 @@ suite "Manifest":
       )
 
     var
-      blocksManifest = Manifest.new(blocks).tryGet()
+      manifest = Manifest.new(blocks).tryGet()
 
     let
-      e = blocksManifest.encode().tryGet()
+      e = manifest.encode().tryGet()
-      manifest = Manifest.decode(e).tryGet()
+      decoded = Manifest.decode(e).tryGet()
 
-    check manifest.blocks == blocks
+    check:
+      decoded.blocks == blocks
+      decoded.protected == false
+
+  test "Should produce a protected manifest":
+    let
+      blocks = (0..<333).mapIt(
+        Block.new(("Block " & $it).toBytes).tryGet().cid
+      )
+      manifest = Manifest.new(blocks).tryGet()
+      protected = Manifest.new(manifest, 2, 2).tryGet()
+
+    check:
+        protected.originalCid == manifest.cid.tryGet()
+        protected.blocks[0..<333] == manifest.blocks
+        protected.protected == true
+        protected.originalLen == manifest.len
+
+    # fill up with empty Cid's
+    for i in protected.rounded..<protected.len:
+      protected.blocks[i] = EmptyCid[manifest.version]
+        .catch
+        .get()[manifest.hcodec]
+        .catch
+        .get()
+
+    var
+      encoded = protected.encode().tryGet()
+      decoded = Manifest.decode(encoded).tryGet()
+
+    check:
+      decoded.protected == true
+      decoded.originalLen == manifest.len
+
+      decoded.K == protected.K
+      decoded.M == protected.M
+
+      decoded.originalCid == protected.originalCid
+      decoded.originalCid == manifest.cid.tryGet()
+
+      decoded.blocks == protected.blocks
+      decoded.blocks[0..<333] == manifest.blocks