feat(stickers): Add content hash and EDN decoding

.gitmodules

@@ -120,3 +120,6 @@
 [submodule "vendor/combparser"]
 	path = vendor/combparser
 	url = https://github.com/PMunch/combparser.git
+[submodule "vendor/edn.nim"]
+	path = vendor/edn.nim
+	url = https://github.com/status-im/edn.nim

status/private/stickers.nim

@@ -0,0 +1,171 @@
+{.push raises: [Defect].}
+
+import # std libs
+  std/strutils
+
+import # vendor libs
+  chronicles, edn, libp2p/[multihash, multicodec, cid], nimcrypto, stint
+
+import
+  ./common, ./util
+
+export cid
+
+type
+  StickersError* = enum
+    CidV0InitFailure      = "stickers: failed to init CIDv0 from codec and multihash"
+    EdnNodeTypeUnknown    = "stickers: couldn't decode EDN, node type unknown"
+    EdnReadError          = "stickers: error reading EDN string"
+    HashValueError        = "stickers: provided hash must not be an empty string"
+    HexIntParseError      = "stickers: error parsing string to hex int"
+    InvalidMultiCodec     = "stickers: content hash contains an invalid codec"
+    MultiHashInitFailure  = "stickers: failed to init MultiHash given the hash"
+
+  StickersResult*[T] = Result[T, StickersError]
+
+  Sticker* = object
+    hash*: string
+    packId*: int
+
+  StickerPack* = object
+    author*: string
+    id*: int
+    name*: string
+    price*: Stuint[256]
+    preview*: string
+    stickers*: seq[Sticker]
+    thumbnail*: string
+
+# forward declaration:
+proc parseNode[T](node: EdnNode, searchName: string): StickersResult[T]
+proc parseMap[T](map: HMap, searchName: string,): StickersResult[T]
+
+proc getValueFromNode[T](node: EdnNode): StickersResult[T] {.raises: [].} =
+  if node.kind == EdnSymbol:
+    when T is string:
+      return ok node.symbol.name
+  elif node.kind == EdnKeyword:
+    when T is string:
+      return ok node.keyword.name
+  elif node.kind == EdnString:
+    when T is string:
+      return ok node.str
+  elif node.kind == EdnCharacter:
+    when T is string:
+      return ok node.character
+  elif node.kind == EdnBool:
+    when T is bool:
+      return ok node.boolVal
+  elif node.kind == EdnInt:
+    when T is int:
+      return ok node.num.int
+  else:
+    return err EdnNodeTypeUnknown
+
+proc parseVector[T: seq[Sticker]](node: EdnNode, searchName: string):
+  StickersResult[T] =
+
+  var vector: T = @[]
+
+  for i in 0..<node.vec.len:
+    var sticker: Sticker
+    let child = node.vec[i]
+    if child.kind == EdnMap:
+      for k, v in sticker.fieldPairs:
+        let parseRes = parseMap[v.type](child.map, k)
+        v = parseRes.get(default v.type)
+      vector.add(sticker)
+
+  return ok vector
+
+proc parseMap[T](map: HMap, searchName: string): StickersResult[T] =
+  var res: StickersResult[T]
+
+  for iBucket in 0..<map.buckets.len:
+    let bucket = map.buckets[iBucket]
+    if bucket.len > 0:
+      for iChild in 0..<bucket.len:
+        let child = bucket[iChild]
+        let isRoot = child.key.kind == EdnSymbol and child.key.symbol.name == "meta"
+        if child.key.kind != EdnKeyword and not isRoot:
+          continue
+        if isRoot or child.key.keyword.name == searchName:
+          if child.value.kind == EdnMap:
+            res = parseMap[T](child.value.map, searchName)
+            break
+          elif child.value.kind == EdnVector:
+            when T is seq[Sticker]:
+              res = parseVector[T](child.value, searchName)
+              break
+          res = getValueFromNode[T](child.value)
+          break
+
+  return res
+
+proc parseNode[T](node: EdnNode, searchName: string): StickersResult[T] =
+  if node.kind == EdnMap:
+    return parseMap[T](node.map, searchName)
+  else:
+    return getValueFromNode[T](node)
+
+proc decode*[T](node: EdnNode): StickersResult[T] =
+  var res = T()
+  for k, v in res.fieldPairs:
+    let parseRes = parseNode[v.type](node, k)
+    v = parseRes.get(default v.type)
+  return ok res
+
+proc decode*[T](edn: string): StickersResult[T] {.raises: [].} =
+  try:
+    return decode[T](edn.read)
+  except IOError, OSError, Exception: # list exception last on purpose
+    return err EdnReadError
+
+proc decodeContentHash*(value: string): StickersResult[Cid] =
+  if value == "":
+    return err HashValueError
+
+  # eg encoded sticker multihash cid:
+  #  e30101701220eab9a8ef4eac6c3e5836a3768d8e04935c10c67d9a700436a0e53199e9b64d29
+  #  e3017012205c531b83da9dd91529a4cf8ecd01cb62c399139e6f767e397d2f038b820c139f (testnet)
+  #  e3011220c04c617170b1f5725070428c01280b4c19ae9083b7e6d71b7a0d2a1b5ae3ce30 (testnet)
+  #
+  # The first 4 bytes (in hex) represent:
+  # e3 = codec identifier "ipfs-ns" for content-hash
+  # 01 = unused - sometimes this is NOT included (ie ropsten)
+  # 01 = CID version (effectively unused, as we will decode with CIDv0 regardless)
+  # 70 = codec identifier "dag-pb"
+
+  # ipfs-ns
+  if value[0..1] != "e3":
+    return err InvalidMultiCodec
+
+  # dag-pb
+  let defaultCodec = ? catch(parseHexInt("70")).mapErrTo(HexIntParseError)
+  var
+    codec = defaultCodec # no codec specified
+    codecStartIdx = 2 # idx of where codec would start if it was specified
+  # handle the case when starts with 0xe30170 instead of 0xe3010170
+  if value[2..5] == "0101":
+    codecStartIdx = 6
+    codec = ? catch(parseHexInt(value[6..7])).mapErrTo(HexIntParseError)
+  elif value[2..3] == "01" and value[4..5] != "12":
+    codecStartIdx = 4
+    codec = ? catch(parseHexInt(value[4..5])).mapErrTo(HexIntParseError)
+
+  # strip the info we no longer need
+  var multiHashStr = value[codecStartIdx + 2..<value.len]
+
+  # The rest of the hash identifies the multihash algo, length, and digest
+  # More info: https://multiformats.io/multihash/
+  # 12 = identifies sha2-256 hash
+  # 20 = multihash length = 32
+  # ...rest = multihash digest
+  let
+    multiHash = ? MultiHash.init(nimcrypto.fromHex(multiHashStr))
+      .mapErrTo(MultiHashInitFailure)
+    cid = Cid.init(CIDv0, MultiCodec.codec(codec), multiHash)
+      .mapErrTo(CidV0InitFailure)
+
+  trace "Decoded sticker hash", cid = $cid.get
+  return cid

test/stickers.nim

@@ -0,0 +1,72 @@
+import # std libs
+  std/unittest
+
+import # status lib
+  chronos, status/private/stickers
+
+import # test modules
+  ./test_helpers
+
+procSuite "stickers":
+  asyncTest "decodeContentHash":
+    var
+      hash = "e30101701220eab9a8ef4eac6c3e5836a3768d8e04935c10c67d9a700436a0e53199e9b64d29"
+      cid = hash.decodeContentHash
+
+    check:
+      cid.isOk
+      $cid.get == "Qme8vJtyrEHxABcSVGPF95PtozDgUyfr1xGjePmFdZgk9v"
+
+    # testnet form #1
+    hash = "e3017012205c531b83da9dd91529a4cf8ecd01cb62c399139e6f767e397d2f038b820c139f"
+    cid = hash.decodeContentHash
+
+    check:
+      cid.isOk
+      $cid.get == "QmUZ3icyt1wQpaPXk1RRvtioMu5LtyuHvjwvtYo4iu58nr"
+
+    # testnet form #2
+    hash = "e3011220c04c617170b1f5725070428c01280b4c19ae9083b7e6d71b7a0d2a1b5ae3ce30"
+    cid = hash.decodeContentHash
+
+    check:
+      cid.isOk
+      $cid.get == "QmbHJYDDW5CRdUfpLFRdJNCEDbZNYvAi7DAAfXrgheM1C3"
+
+    # blank
+    hash = ""
+    cid = hash.decodeContentHash
+
+    check:
+      cid.isErr
+      cid.error == HashValueError
+
+    # wrong codec
+    hash = "e4"
+    cid = hash.decodeContentHash
+
+    check:
+      cid.isErr
+      cid.error == InvalidMultiCodec
+
+  asyncTest "decode edn":
+    var
+      edn = """{meta {:name      "Dogeth"
+                 :author    "Mugen Flen"
+                 :thumbnail "e3010170122094d3d16b41d6882dbc93e1690d945d0c00a2869cea94d0939f3ba3c0399685e6"
+                 :preview   "e301017012204d6059ec0fab356add176ad2b2dd95656e50cb1e822232c00a30df04efa50378"
+                 :stickers [{:hash "e3010170122094d3d16b41d6882dbc93e1690d945d0c00a2869cea94d0939f3ba3c0399685e6"}{:hash "e30101701220fcd853d7633d411a7002f286c8316336823c71114f52d672361300deb4760596"}{:hash "e3010170122058c8e08765a5d8a103f036ae65e6a3ba3f110fefb859965b213f92c293972bf5"}{:hash "e30101701220f7d8386783bf8691428389379bedaf94c79011a1fb1f17677c3d1582ddc8ab97"}{:hash "e3010170122040f0a7a6cfa8c281eeda40f6ba65667f07ab861e1c78f1374c738f1ca2161a31"}{:hash "e30101701220ac7cf793ac2baa36bd69dd10462b45831d85bbdf375f19a29a62dec78a9f8d3c"}{:hash "e3010170122070acac3d71c6243c5d100c2e6a53de7812fb42528236a0c3a4e2f4b2e61c6662"}{:hash "e301017012205aac43b08a22ddf3f40cacba2fa2f72251eb2c6bfb21fb46f8c0586a4655dc50"}{:hash "e3010170122092e871abca1681bbb46c9869fa6f449e85591accb16fac8130819f7ebbcf4305"}{:hash "e301017012204005f3279924ac12b1a396c20c7313f2356d1920d8ef3a2c60072e1223b8d4c8"}{:hash "e30101701220d655e130a998c54f3f68b23b52fe5a08b8f25f98b52270f9b438cd000bb2c719"}{:hash "e301017012207de9418dcb3a12feeb7c1d54e71ca45da8344c61a828ffab5285138da5a9b3a9"}{:hash "e3010170122073d50f10d4cebc4a816e4c6c86cd2ad28e03ba8b64279750113a2dcc893ba773"}{:hash "e30101701220adb1b6799d69d994a46eaedd2ba63a00b086355ae4ed0182c28173cd9df17797"}{:hash "e301017012205b7764a62aa6d7999ea1698d901c3048f42cafee61625584cb6f67ae14b36f70"}]}}"""
+      decoded = edn.decode[:StickerPack]()
+
+    check decoded.isOk
+    let pack = decoded.get
+    check:
+      pack.author == "Mugen Flen"
+      pack.name == "Dogeth"
+      pack.preview == "e301017012204d6059ec0fab356add176ad2b2dd95656e50cb1e822232c00a30df04efa50378"
+      pack.thumbnail == "e3010170122094d3d16b41d6882dbc93e1690d945d0c00a2869cea94d0939f3ba3c0399685e6"
+      pack.stickers.len == 15
+      pack.stickers[0].hash == "e3010170122094d3d16b41d6882dbc93e1690d945d0c00a2869cea94d0939f3ba3c0399685e6"
+      pack.stickers[14].hash == "e301017012205b7764a62aa6d7999ea1698d901c3048f42cafee61625584cb6f67ae14b36f70"
+
+

test/test_all.nim

@@ -18,6 +18,7 @@ import # test modules
   ./pendingtxs,
   ./permissions,
   ./settings,
+  ./stickers,
   ./tokens,
   ./tx_history
   # ./waku_smoke