feat: replace nim-libp2p protobuf with nim-protobuf-serialization

libp2p was pulled in solely for its `minprotobuf` field codec, dragging in its full transitive tree (secp256k1, nimcrypto, websock, etc.). Swap it for nim-protobuf-serialization, whose low-level `codec` module gives the same protobuf wire primitives without the networking stack. The wire/snapshot codecs build messages by hand at the field level and rely on a backward-compatible decode path the type-driven `Protobuf.encode/decode` API cannot express. To keep that code intact, `protobufutil.nim` is a thin `ProtoBuffer` shim over the new `codec` module, preserving the exact field-level behaviour the codecs depend on (plain varints, length-delimited bytes/strings with no UTF-8 validation, unknown-wire-type fields skipped as protoc does). Dependency closure (nimble.lock, nix/deps.nix) regenerated accordingly: libp2p and its 8 exclusive transitive deps dropped, protobuf_serialization and its npeg dependency added. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-02 13:59:41 +00:00 · 2026-06-10 15:46:14 +02:00 · 2026-06-10 15:46:14 +02:00 · e2ec4d55b3
commit e2ec4d55b3
parent c4d41aa5a5
7 changed files with 247 additions and 237 deletions
--- a/nimble.lock
+++ b/nimble.lock
@ -23,18 +23,6 @@
        "sha1": "7e068f119664cf47ad0cfb74ef4c56fb6b616523"
      }
    },
-    "bearssl_pkey_decoder": {
-      "version": "0.1.0",
-      "vcsRevision": "21dd3710df9345ed2ad8bf8f882761e07863b8e0",
-      "url": "https://github.com/vacp2p/bearssl_pkey_decoder",
-      "downloadMethod": "git",
-      "dependencies": [
-        "bearssl"
-      ],
-      "checksums": {
-        "sha1": "21b42e2e6ddca6c875d3fc50f36a5115abf51714"
-      }
-    },
    "results": {
      "version": "0.5.1",
      "vcsRevision": "df8113dda4c2d74d460a8fa98252b0b771bf1f27",
@ -85,6 +73,32 @@
        "sha1": "fa35c1bb76a0a02a2379fe86eaae0957c7527cb8"
      }
    },
+    "npeg": {
+      "version": "1.3.0",
+      "vcsRevision": "409f6796d0e880b3f0222c964d1da7de6e450811",
+      "url": "https://github.com/zevv/npeg",
+      "downloadMethod": "git",
+      "dependencies": [],
+      "checksums": {
+        "sha1": "64f15c85a059c889cb11c5fe72372677c50da621"
+      }
+    },
+    "protobuf_serialization": {
+      "version": "0.4.0",
+      "vcsRevision": "38d24eb3bd93e605fb88199da71d36b1ec0ad60d",
+      "url": "https://github.com/status-im/nim-protobuf-serialization",
+      "downloadMethod": "git",
+      "dependencies": [
+        "stew",
+        "faststreams",
+        "serialization",
+        "npeg",
+        "unittest2"
+      ],
+      "checksums": {
+        "sha1": "5a7a80fb8cca29e41899ce9540b74e49c874f8fd"
+      }
+    },
    "json_serialization": {
      "version": "0.4.4",
      "vcsRevision": "c343b0e243d9e17e2c40f3a8a24340f7c4a71d44",
@ -157,39 +171,6 @@
        "sha1": "455802a90204d8ad6b31d53f2efff8ebfe4c834a"
      }
    },
-    "dnsclient": {
-      "version": "0.3.4",
-      "vcsRevision": "23214235d4784d24aceed99bbfe153379ea557c8",
-      "url": "https://github.com/ba0f3/dnsclient.nim",
-      "downloadMethod": "git",
-      "dependencies": [],
-      "checksums": {
-        "sha1": "65262c7e533ff49d6aca5539da4bc6c6ce132f40"
-      }
-    },
-    "jwt": {
-      "version": "0.2",
-      "vcsRevision": "18f8378de52b241f321c1f9ea905456e89b95c6f",
-      "url": "https://github.com/vacp2p/nim-jwt.git",
-      "downloadMethod": "git",
-      "dependencies": [
-        "bearssl",
-        "bearssl_pkey_decoder"
-      ],
-      "checksums": {
-        "sha1": "bcfd6fc9c5e10a52b87117219b7ab5c98136bc8e"
-      }
-    },
-    "nimcrypto": {
-      "version": "0.7.3",
-      "vcsRevision": "b3dbc9c4d08e58c5b7bfad6dc7ef2ee52f2f4c08",
-      "url": "https://github.com/cheatfate/nimcrypto",
-      "downloadMethod": "git",
-      "dependencies": [],
-      "checksums": {
-        "sha1": "f72b90fe3f4da09efa482de4f8729e7ee4abea2f"
-      }
-    },
    "metrics": {
      "version": "0.1.2",
      "vcsRevision": "11d0cddfb0e711aa2a8c75d1892ae24a64c299fc",
@ -204,93 +185,6 @@
        "sha1": "5cdac99d85d3c146d170e85064c88fb28f377842"
      }
    },
-    "secp256k1": {
-      "version": "0.6.0.3.2",
-      "vcsRevision": "d8f1288b7c72f00be5fc2c5ea72bf5cae1eafb15",
-      "url": "https://github.com/status-im/nim-secp256k1",
-      "downloadMethod": "git",
-      "dependencies": [
-        "stew",
-        "results",
-        "nimcrypto"
-      ],
-      "checksums": {
-        "sha1": "6618ef9de17121846a8c1d0317026b0ce8584e10"
-      }
-    },
-    "zlib": {
-      "version": "0.1.0",
-      "vcsRevision": "e680f269fb01af2c34a2ba879ff281795a5258fe",
-      "url": "https://github.com/status-im/nim-zlib",
-      "downloadMethod": "git",
-      "dependencies": [
-        "stew",
-        "results"
-      ],
-      "checksums": {
-        "sha1": "bbde4f5a97a84b450fef7d107461e5f35cf2b47f"
-      }
-    },
-    "websock": {
-      "version": "0.2.1",
-      "vcsRevision": "35ae76f1559e835c80f9c1a3943bf995d3dd9eb5",
-      "url": "https://github.com/status-im/nim-websock",
-      "downloadMethod": "git",
-      "dependencies": [
-        "chronos",
-        "httputils",
-        "chronicles",
-        "stew",
-        "nimcrypto",
-        "bearssl",
-        "results",
-        "zlib"
-      ],
-      "checksums": {
-        "sha1": "1cb5efa10cd389bc01d0707c242ae010c76a03cd"
-      }
-    },
-    "lsquic": {
-      "version": "0.0.1",
-      "vcsRevision": "4fb03ee7bfb39aecb3316889fdcb60bec3d0936f",
-      "url": "https://github.com/vacp2p/nim-lsquic",
-      "downloadMethod": "git",
-      "dependencies": [
-        "zlib",
-        "stew",
-        "chronos",
-        "nimcrypto",
-        "unittest2",
-        "chronicles"
-      ],
-      "checksums": {
-        "sha1": "f465fa994346490d0924d162f53d9b5aec62f948"
-      }
-    },
-    "libp2p": {
-      "version": "1.15.2",
-      "vcsRevision": "ca48c3718246bb411ff0e354a70cb82d9a28de0d",
-      "url": "https://github.com/vacp2p/nim-libp2p",
-      "downloadMethod": "git",
-      "dependencies": [
-        "nimcrypto",
-        "dnsclient",
-        "bearssl",
-        "chronicles",
-        "chronos",
-        "metrics",
-        "secp256k1",
-        "stew",
-        "websock",
-        "unittest2",
-        "results",
-        "lsquic",
-        "jwt"
-      ],
-      "checksums": {
-        "sha1": "3b2cdc7e00261eb4210ca3d44ec3bd64c2b7bbba"
-      }
-    },
    "stint": {
      "version": "0.8.2",
      "vcsRevision": "470b7892561b5179ab20bd389a69217d6213fe58",
--- a/nix/deps.nix
+++ b/nix/deps.nix
@ -17,13 +17,6 @@
    fetchSubmodules = true;
  };

-  bearssl_pkey_decoder = pkgs.fetchgit {
-    url = "https://github.com/vacp2p/bearssl_pkey_decoder";
-    rev = "21dd3710df9345ed2ad8bf8f882761e07863b8e0";
-    sha256 = "0bl3f147zmkazbhdkr4cj1nipf9rqiw3g4hh1j424k9hpl55zdpg";
-    fetchSubmodules = true;
-  };
-
  results = pkgs.fetchgit {
    url = "https://github.com/arnetheduck/nim-results";
    rev = "df8113dda4c2d74d460a8fa98252b0b771bf1f27";
@ -52,6 +45,20 @@
    fetchSubmodules = true;
  };

+  npeg = pkgs.fetchgit {
+    url = "https://github.com/zevv/npeg";
+    rev = "409f6796d0e880b3f0222c964d1da7de6e450811";
+    sha256 = "1h2f5znbpa3svk7wsw2axn8f7f59d23xq85z148kiv6fqh0ffwbm";
+    fetchSubmodules = true;
+  };
+
+  protobuf_serialization = pkgs.fetchgit {
+    url = "https://github.com/status-im/nim-protobuf-serialization";
+    rev = "38d24eb3bd93e605fb88199da71d36b1ec0ad60d";
+    sha256 = "0jr0a41b4r444si6xfa7bclw8mjsk6id10lrdvbxzp99750zspb9";
+    fetchSubmodules = true;
+  };
+
  json_serialization = pkgs.fetchgit {
    url = "https://github.com/status-im/nim-json-serialization";
    rev = "c343b0e243d9e17e2c40f3a8a24340f7c4a71d44";
@ -87,27 +94,6 @@
    fetchSubmodules = true;
  };

-  dnsclient = pkgs.fetchgit {
-    url = "https://github.com/ba0f3/dnsclient.nim";
-    rev = "23214235d4784d24aceed99bbfe153379ea557c8";
-    sha256 = "03mf3lw5c0m5nq9ppa49nylrl8ibkv2zzlc0wyhqg7w09kz6hks6";
-    fetchSubmodules = true;
-  };
-
-  jwt = pkgs.fetchgit {
-    url = "https://github.com/vacp2p/nim-jwt.git";
-    rev = "18f8378de52b241f321c1f9ea905456e89b95c6f";
-    sha256 = "1986czmszdxj6g9yr7xn1fx8y2y9mwpb3f1bn9nc6973qawsdm0p";
-    fetchSubmodules = true;
-  };
-
-  nimcrypto = pkgs.fetchgit {
-    url = "https://github.com/cheatfate/nimcrypto";
-    rev = "b3dbc9c4d08e58c5b7bfad6dc7ef2ee52f2f4c08";
-    sha256 = "1v4rz42lwcazs6isi3kmjylkisr84mh0kgmlqycx4i885dn3g0l4";
-    fetchSubmodules = true;
-  };
-
  metrics = pkgs.fetchgit {
    url = "https://github.com/status-im/nim-metrics";
    rev = "11d0cddfb0e711aa2a8c75d1892ae24a64c299fc";
@ -115,41 +101,6 @@
    fetchSubmodules = true;
  };

-  secp256k1 = pkgs.fetchgit {
-    url = "https://github.com/status-im/nim-secp256k1";
-    rev = "d8f1288b7c72f00be5fc2c5ea72bf5cae1eafb15";
-    sha256 = "1qjrmwbngb73f6r1fznvig53nyal7wj41d1cmqfksrmivk2sgrn2";
-    fetchSubmodules = true;
-  };
-
-  zlib = pkgs.fetchgit {
-    url = "https://github.com/status-im/nim-zlib";
-    rev = "e680f269fb01af2c34a2ba879ff281795a5258fe";
-    sha256 = "1xw9f1gjsgqihdg7kdkbaq1wankgnx2vn9l3ihc6nqk2jzv5bvk5";
-    fetchSubmodules = true;
-  };
-
-  websock = pkgs.fetchgit {
-    url = "https://github.com/status-im/nim-websock";
-    rev = "35ae76f1559e835c80f9c1a3943bf995d3dd9eb5";
-    sha256 = "1j6dklzb6b6bv2aiglbiyflja2vdpmyxfirv98f49y62mykq0yrw";
-    fetchSubmodules = true;
-  };
-
-  lsquic = pkgs.fetchgit {
-    url = "https://github.com/vacp2p/nim-lsquic";
-    rev = "4fb03ee7bfb39aecb3316889fdcb60bec3d0936f";
-    sha256 = "0qdhcd4hyp185szc9sv3jvwdwc9zp3j0syy7glxv13k9bchfmkfg";
-    fetchSubmodules = true;
-  };
-
-  libp2p = pkgs.fetchgit {
-    url = "https://github.com/vacp2p/nim-libp2p";
-    rev = "ca48c3718246bb411ff0e354a70cb82d9a28de0d";
-    sha256 = "07qfjjrq6w7bj9dbchvcrpla47jidngbrgmigbhl7fh3cfkdabc9";
-    fetchSubmodules = true;
-  };
-
  stint = pkgs.fetchgit {
    url = "https://github.com/status-im/nim-stint";
    rev = "470b7892561b5179ab20bd389a69217d6213fe58";
@ -166,8 +117,8 @@

  ffi = pkgs.fetchgit {
    url = "https://github.com/logos-messaging/nim-ffi";
-    rev = "fb25f069d2dfae2b543d79d2c1a81f197de22a2b";
-    sha256 = "0zkjnrm2yjlw27q99kv2x8ll61mbz4nr0cvmyq0csydh43c08k0p";
+    rev = "d4c87c1f94c4678eea7d32a8f5f41c72420fadb6";
+    sha256 = "14dm92l3wl8sc5a108612r1cgjvxksy2chzmn1asph6frl4lm641";
    fetchSubmodules = true;
  };

--- a/sds.nimble
+++ b/sds.nimble
@ -10,7 +10,7 @@ srcDir = "sds"
 # Dependencies
 requires "nim >= 2.2.4"
 requires "chronos >= 4.0.4"
-requires "libp2p >= 1.15.2"
+requires "protobuf_serialization >= 0.4.0"
 requires "chronicles"
 requires "stew"
 requires "stint"
--- a/sds/protobuf.nim
+++ b/sds/protobuf.nim
@ -1,4 +1,3 @@
-import libp2p/protobuf/minprotobuf
 import endians
 import ./types/[sds_message_id, history_entry, sds_message, reliability_error]
 import ./protobufutil
@ -6,7 +5,7 @@ import ./bloom
 import ./sds_utils

 proc encodeHistoryEntry*(entry: HistoryEntry): ProtoBuffer =
-  var entryPb = initProtoBuffer()
+  var entryPb = ProtoBuffer.init()
  entryPb.write(1, entry.messageId)
  if entry.retrievalHint.len > 0:
    entryPb.write(2, entry.retrievalHint)
@ -26,7 +25,7 @@ proc decodeHistoryEntry*(entryPb: ProtoBuffer): ProtobufResult[HistoryEntry] =
  ok(entry)

 proc encode*(msg: SdsMessage): ProtoBuffer =
-  var pb = initProtoBuffer()
+  var pb = ProtoBuffer.init()

  pb.write(1, msg.messageId)
  pb.write(2, uint64(msg.lamportTimestamp))
@ -51,7 +50,7 @@ proc encode*(msg: SdsMessage): ProtoBuffer =
  return pb

 proc decode*(T: type SdsMessage, buffer: seq[byte]): ProtobufResult[T] =
-  let pb = initProtoBuffer(buffer)
+  let pb = ProtoBuffer.init(buffer)
  var msg = SdsMessage.init("", 0, @[], "", @[], @[])

  if not ?pb.getField(1, msg.messageId):
@ -67,7 +66,7 @@ proc decode*(T: type SdsMessage, buffer: seq[byte]): ProtobufResult[T] =
  if pb.getRepeatedField(3, historyBuffers).isOk():
    # New format: repeated HistoryEntry
    for histBuffer in historyBuffers:
-      let entryPb = initProtoBuffer(histBuffer)
+      let entryPb = ProtoBuffer.init(histBuffer)
      let entry = ?decodeHistoryEntry(entryPb)
      msg.causalHistory.add(entry)
  else:
@ -95,7 +94,7 @@ proc decode*(T: type SdsMessage, buffer: seq[byte]): ProtobufResult[T] =
  var repairBuffers: seq[seq[byte]]
  if pb.getRepeatedField(13, repairBuffers).isOk():
    for repairBuffer in repairBuffers:
-      let entryPb = initProtoBuffer(repairBuffer)
+      let entryPb = ProtoBuffer.init(repairBuffer)
      let entry = ?decodeHistoryEntry(entryPb)
      msg.repairRequest.add(entry)

@ -104,7 +103,7 @@ proc decode*(T: type SdsMessage, buffer: seq[byte]): ProtobufResult[T] =
 proc extractChannelId*(data: seq[byte]): Result[SdsChannelID, ReliabilityError] =
  ## For extraction of channel ID without full message deserialization
  try:
-    let pb = initProtoBuffer(data)
+    let pb = ProtoBuffer.init(data)
    var channelId: SdsChannelID
    let fieldOk = pb.getField(4, channelId).valueOr:
      return err(ReliabilityError.reDeserializationError)
@ -124,7 +123,7 @@ proc deserializeMessage*(data: seq[byte]): Result[SdsMessage, ReliabilityError]
  return ok(msg)

 proc serializeBloomFilter*(filter: BloomFilter): Result[seq[byte], ReliabilityError] =
-  var pb = initProtoBuffer()
+  var pb = ProtoBuffer.init()

  try:
    var bytes = newSeq[byte](filter.intArray.len * sizeof(int))
@ -149,7 +148,7 @@ proc deserializeBloomFilter*(data: seq[byte]): Result[BloomFilter, ReliabilityEr
  if data.len == 0:
    return err(ReliabilityError.reDeserializationError)

-  let pb = initProtoBuffer(data)
+  let pb = ProtoBuffer.init(data)
  var bytes: seq[byte]
  var cap, errRate, kHashes, mBits: uint64

--- a/sds/protobufutil.nim
+++ b/sds/protobufutil.nim
@ -1,19 +1,175 @@
-# adapted from https://github.com/waku-org/nwaku/blob/master/waku/common/protobuf.nim
+# Minimal hand-rolled protobuf field codec, a thin shim over
+# `nim-protobuf-serialization`'s low-level wire `codec` module.
+#
+# `sds/protobuf.nim` and `sds/snapshot_codec.nim` build messages by hand at the
+# field level — including a backward-compatible decode path the type-driven
+# `Protobuf.encode/decode` API cannot express — so this exposes a small
+# accumulating `ProtoBuffer` with `write`/`getField`/`getRepeatedField`/`finish`:
+#   * unsigned integers encode as plain varints (last value wins on decode);
+#   * strings and byte seqs encode length-delimited, with no UTF-8 validation
+#     (strings are treated as opaque bytes — message ids may be binary);
+#   * a field whose stored wire type differs from the requested one is skipped,
+#     as `protoc` does; only a malformed buffer yields an error.

 {.push raises: [].}

-import libp2p/protobuf/minprotobuf
-import libp2p/varint
+import results
+import faststreams/inputs
+from protobuf_serialization/codec import
+  FieldHeader, WireKind, init, number, kind, toBytes, readHeader, readValue,
+  puint64, pbytes, fixed64, fixed32
 import ./types/protobuf_error

-export minprotobuf, varint, protobuf_error
+export results, protobuf_error

-converter toProtobufError*(err: minprotobuf.ProtoError): ProtobufError =
+type ProtoBuffer* = object ## Accumulating protobuf field buffer.
+  buffer*: seq[byte]
+
+converter toProtobufError*(err: ProtoError): ProtobufError =
  case err
-  of minprotobuf.ProtoError.RequiredFieldMissing:
+  of ProtoError.RequiredFieldMissing:
    return ProtobufError(kind: ProtobufErrorKind.MissingRequiredField, field: "unknown")
  else:
    return ProtobufError(kind: ProtobufErrorKind.DecodeFailure, error: err)

 proc missingRequiredField*(T: type ProtobufError, field: string): T =
  return ProtobufError.init(field)
+
+# ---------------------------------------------------------------------------
+# Construction
+# ---------------------------------------------------------------------------
+
+proc init*(T: type ProtoBuffer): T =
+  return T(buffer: @[])
+
+proc init*(T: type ProtoBuffer, data: seq[byte]): T =
+  return T(buffer: data)
+
+proc finish*(pb: var ProtoBuffer) =
+  ## No length prefix is used, so finishing only asserts the invariant that a
+  ## top-level buffer is never empty.
+  doAssert(pb.buffer.len > 0)
+
+# ---------------------------------------------------------------------------
+# Writing
+# ---------------------------------------------------------------------------
+
+proc writeVarint(pb: var ProtoBuffer, field: int, value: uint64) =
+  pb.buffer.add(toBytes(FieldHeader.init(field, WireKind.Varint)))
+  pb.buffer.add(toBytes(puint64(value)))
+
+proc write*(pb: var ProtoBuffer, field: int, value: uint64) =
+  pb.writeVarint(field, value)
+
+proc write*(pb: var ProtoBuffer, field: int, value: uint32) =
+  pb.writeVarint(field, uint64(value))
+
+proc writeLengthDelim(pb: var ProtoBuffer, field: int, data: openArray[byte]) =
+  pb.buffer.add(toBytes(FieldHeader.init(field, WireKind.LengthDelim)))
+  pb.buffer.add(toBytes(puint64(uint64(data.len))))
+  if data.len > 0:
+    pb.buffer.add(data)
+
+proc write*(pb: var ProtoBuffer, field: int, value: openArray[byte]) =
+  pb.writeLengthDelim(field, value)
+
+proc write*(pb: var ProtoBuffer, field: int, value: string) =
+  pb.writeLengthDelim(field, value.toOpenArrayByte(0, value.high))
+
+# ---------------------------------------------------------------------------
+# Reading
+# ---------------------------------------------------------------------------
+
+proc bytesToString(b: seq[byte]): string =
+  ## Copy raw bytes into a string without UTF-8 validation — protobuf strings
+  ## are opaque bytes here, and message ids may not be valid UTF-8.
+  var s = newString(b.len)
+  if b.len > 0:
+    copyMem(addr s[0], unsafeAddr b[0], b.len)
+  return s
+
+proc collectVarints(buffer: seq[byte], field: int): ProtoResult[seq[uint64]] =
+  ## All varint values stored at `field`, in order. Mismatched wire types at
+  ## the same field number are skipped, as protoc does.
+  var values: seq[uint64]
+  var sh = memoryInput(buffer)
+  try:
+    let stream = sh.s
+    while stream.readable:
+      let hdr = readHeader(stream)
+      if hdr.number == field and hdr.kind == WireKind.Varint:
+        values.add(uint64(readValue(stream, puint64)))
+      else:
+        case hdr.kind
+        of WireKind.Varint: discard readValue(stream, puint64)
+        of WireKind.Fixed64: discard readValue(stream, fixed64)
+        of WireKind.Fixed32: discard readValue(stream, fixed32)
+        of WireKind.LengthDelim: discard readValue(stream, pbytes)
+  except CatchableError:
+    return err(ProtoError.VarintDecode)
+  return ok(values)
+
+proc collectLengthDelims(buffer: seq[byte], field: int): ProtoResult[seq[seq[byte]]] =
+  ## All length-delimited values stored at `field`, in order.
+  var values: seq[seq[byte]]
+  var sh = memoryInput(buffer)
+  try:
+    let stream = sh.s
+    while stream.readable:
+      let hdr = readHeader(stream)
+      if hdr.number == field and hdr.kind == WireKind.LengthDelim:
+        values.add(seq[byte](readValue(stream, pbytes)))
+      else:
+        case hdr.kind
+        of WireKind.Varint: discard readValue(stream, puint64)
+        of WireKind.Fixed64: discard readValue(stream, fixed64)
+        of WireKind.Fixed32: discard readValue(stream, fixed32)
+        of WireKind.LengthDelim: discard readValue(stream, pbytes)
+  except CatchableError:
+    return err(ProtoError.VarintDecode)
+  return ok(values)
+
+proc getField*(pb: ProtoBuffer, field: int, output: var uint64): ProtoResult[bool] =
+  let values = ?collectVarints(pb.buffer, field)
+  if values.len > 0:
+    output = values[^1]
+    return ok(true)
+  return ok(false)
+
+proc getField*(pb: ProtoBuffer, field: int, output: var uint32): ProtoResult[bool] =
+  let values = ?collectVarints(pb.buffer, field)
+  if values.len > 0:
+    output = uint32(values[^1])
+    return ok(true)
+  return ok(false)
+
+proc getField*(pb: ProtoBuffer, field: int, output: var seq[byte]): ProtoResult[bool] =
+  let values = ?collectLengthDelims(pb.buffer, field)
+  if values.len > 0:
+    output = values[^1]
+    return ok(true)
+  return ok(false)
+
+proc getField*(pb: ProtoBuffer, field: int, output: var string): ProtoResult[bool] =
+  let values = ?collectLengthDelims(pb.buffer, field)
+  if values.len > 0:
+    output = bytesToString(values[^1])
+    return ok(true)
+  return ok(false)
+
+proc getRepeatedField*(
+    pb: ProtoBuffer, field: int, output: var seq[seq[byte]]
+): ProtoResult[bool] =
+  output = ?collectLengthDelims(pb.buffer, field)
+  return ok(output.len > 0)
+
+proc getRepeatedField*(
+    pb: ProtoBuffer, field: int, output: var seq[string]
+): ProtoResult[bool] =
+  let values = ?collectLengthDelims(pb.buffer, field)
+  output.setLen(0)
+  for v in values:
+    output.add(bytesToString(v))
+  return ok(output.len > 0)
+
+{.pop.}
--- a/sds/snapshot_codec.nim
+++ b/sds/snapshot_codec.nim
@ -13,7 +13,6 @@
 {.push raises: [].}

 import std/[sets, times]
-import libp2p/protobuf/minprotobuf
 import ./types/[
  channel_meta, history_update, sds_message, sds_message_id, history_entry,
  unacknowledged_message, incoming_message, repair_entry, reliability_error,
@ -44,7 +43,7 @@ proc fromUnixMs(ms: int64): Time =
 # ---------------------------------------------------------------------------

 proc encodeUnacked(u: UnacknowledgedMessage): ProtoBuffer =
-  var pb = initProtoBuffer()
+  var pb = ProtoBuffer.init()
  let msgPb = wire.encode(u.message)
  pb.write(1, msgPb.buffer)
  pb.write(2, uint64(u.sendTime.toUnixMs))
@ -53,7 +52,7 @@ proc encodeUnacked(u: UnacknowledgedMessage): ProtoBuffer =
  pb

 proc decodeUnacked(buf: seq[byte]): ProtobufResult[UnacknowledgedMessage] =
-  let pb = initProtoBuffer(buf)
+  let pb = ProtoBuffer.init(buf)
  var msgBytes: seq[byte]
  if not ?pb.getField(1, msgBytes):
    return err(ProtobufError.missingRequiredField("UnacknowledgedMessage.message"))
@ -77,7 +76,7 @@ proc decodeUnacked(buf: seq[byte]): ProtobufResult[UnacknowledgedMessage] =
 # ---------------------------------------------------------------------------

 proc encodeIncoming(m: IncomingMessage): ProtoBuffer =
-  var pb = initProtoBuffer()
+  var pb = ProtoBuffer.init()
  let msgPb = wire.encode(m.message)
  pb.write(1, msgPb.buffer)
  for dep in m.missingDeps:
@ -86,7 +85,7 @@ proc encodeIncoming(m: IncomingMessage): ProtoBuffer =
  pb

 proc decodeIncoming(buf: seq[byte]): ProtobufResult[IncomingMessage] =
-  let pb = initProtoBuffer(buf)
+  let pb = ProtoBuffer.init(buf)
  var msgBytes: seq[byte]
  if not ?pb.getField(1, msgBytes):
    return err(ProtobufError.missingRequiredField("IncomingMessage.message"))
@ -104,7 +103,7 @@ proc decodeIncoming(buf: seq[byte]): ProtobufResult[IncomingMessage] =
 # ---------------------------------------------------------------------------

 proc encodeOutRepairEntry(e: OutgoingRepairEntry): ProtoBuffer =
-  var pb = initProtoBuffer()
+  var pb = ProtoBuffer.init()
  let histPb = wire.encodeHistoryEntry(e.outHistEntry)
  pb.write(1, histPb.buffer)
  pb.write(2, uint64(e.minTimeRepairReq.toUnixMs))
@ -112,11 +111,11 @@ proc encodeOutRepairEntry(e: OutgoingRepairEntry): ProtoBuffer =
  pb

 proc decodeOutRepairEntry(buf: seq[byte]): ProtobufResult[OutgoingRepairEntry] =
-  let pb = initProtoBuffer(buf)
+  let pb = ProtoBuffer.init(buf)
  var histBytes: seq[byte]
  if not ?pb.getField(1, histBytes):
    return err(ProtobufError.missingRequiredField("OutgoingRepairEntry.outHistEntry"))
-  let histPb = initProtoBuffer(histBytes)
+  let histPb = ProtoBuffer.init(histBytes)
  let entry = ?wire.decodeHistoryEntry(histPb)
  var ms: uint64
  if not ?pb.getField(2, ms):
@ -128,7 +127,7 @@ proc decodeOutRepairEntry(buf: seq[byte]): ProtobufResult[OutgoingRepairEntry] =
  )

 proc encodeOutRepairKV(kv: OutgoingRepairKV): ProtoBuffer =
-  var pb = initProtoBuffer()
+  var pb = ProtoBuffer.init()
  pb.write(1, kv.messageId)
  let entryPb = encodeOutRepairEntry(kv.entry)
  pb.write(2, entryPb.buffer)
@ -136,7 +135,7 @@ proc encodeOutRepairKV(kv: OutgoingRepairKV): ProtoBuffer =
  pb

 proc decodeOutRepairKV(buf: seq[byte]): ProtobufResult[OutgoingRepairKV] =
-  let pb = initProtoBuffer(buf)
+  let pb = ProtoBuffer.init(buf)
  var msgId: SdsMessageID
  if not ?pb.getField(1, msgId):
    return err(ProtobufError.missingRequiredField("OutgoingRepairKV.messageId"))
@ -151,7 +150,7 @@ proc decodeOutRepairKV(buf: seq[byte]): ProtobufResult[OutgoingRepairKV] =
 # ---------------------------------------------------------------------------

 proc encodeInRepairEntry(e: IncomingRepairEntry): ProtoBuffer =
-  var pb = initProtoBuffer()
+  var pb = ProtoBuffer.init()
  let histPb = wire.encodeHistoryEntry(e.inHistEntry)
  pb.write(1, histPb.buffer)
  pb.write(2, e.cachedMessage)
@ -160,11 +159,11 @@ proc encodeInRepairEntry(e: IncomingRepairEntry): ProtoBuffer =
  pb

 proc decodeInRepairEntry(buf: seq[byte]): ProtobufResult[IncomingRepairEntry] =
-  let pb = initProtoBuffer(buf)
+  let pb = ProtoBuffer.init(buf)
  var histBytes: seq[byte]
  if not ?pb.getField(1, histBytes):
    return err(ProtobufError.missingRequiredField("IncomingRepairEntry.inHistEntry"))
-  let histPb = initProtoBuffer(histBytes)
+  let histPb = ProtoBuffer.init(histBytes)
  let entry = ?wire.decodeHistoryEntry(histPb)
  var cached: seq[byte]
  if not ?pb.getField(2, cached):
@ -181,7 +180,7 @@ proc decodeInRepairEntry(buf: seq[byte]): ProtobufResult[IncomingRepairEntry] =
  )

 proc encodeInRepairKV(kv: IncomingRepairKV): ProtoBuffer =
-  var pb = initProtoBuffer()
+  var pb = ProtoBuffer.init()
  pb.write(1, kv.messageId)
  let entryPb = encodeInRepairEntry(kv.entry)
  pb.write(2, entryPb.buffer)
@ -189,7 +188,7 @@ proc encodeInRepairKV(kv: IncomingRepairKV): ProtoBuffer =
  pb

 proc decodeInRepairKV(buf: seq[byte]): ProtobufResult[IncomingRepairKV] =
-  let pb = initProtoBuffer(buf)
+  let pb = ProtoBuffer.init(buf)
  var msgId: SdsMessageID
  if not ?pb.getField(1, msgId):
    return err(ProtobufError.missingRequiredField("IncomingRepairKV.messageId"))
@ -204,7 +203,7 @@ proc decodeInRepairKV(buf: seq[byte]): ProtobufResult[IncomingRepairKV] =
 # ---------------------------------------------------------------------------

 proc encode*(meta: ChannelMeta): ProtoBuffer =
-  var pb = initProtoBuffer()
+  var pb = ProtoBuffer.init()
  pb.write(1, meta.schemaVersion)
  pb.write(2, uint64(meta.lamportTimestamp))
  for u in meta.outgoingBuffer:
@ -223,7 +222,7 @@ proc encode*(meta: ChannelMeta): ProtoBuffer =
  pb

 proc decode*(T: type ChannelMeta, buf: seq[byte]): ProtobufResult[T] =
-  let pb = initProtoBuffer(buf)
+  let pb = ProtoBuffer.init(buf)
  var meta = ChannelMeta.init()

  var ver: uint32
@ -271,7 +270,7 @@ proc deserializeChannelMeta*(
 # ---------------------------------------------------------------------------

 proc encode*(d: ChannelData): ProtoBuffer =
-  var pb = initProtoBuffer()
+  var pb = ProtoBuffer.init()
  let metaPb = encode(d.meta)
  pb.write(1, metaPb.buffer)
  for m in d.messageHistory:
@ -281,7 +280,7 @@ proc encode*(d: ChannelData): ProtoBuffer =
  pb

 proc decode*(T: type ChannelData, buf: seq[byte]): ProtobufResult[T] =
-  let pb = initProtoBuffer(buf)
+  let pb = ProtoBuffer.init(buf)
  var d = ChannelData.init()
  var metaBytes: seq[byte]
  if not ?pb.getField(1, metaBytes):
@ -300,7 +299,7 @@ proc decode*(T: type ChannelData, buf: seq[byte]): ProtobufResult[T] =
 # ---------------------------------------------------------------------------

 proc encode*(u: HistoryUpdate): ProtoBuffer =
-  var pb = initProtoBuffer()
+  var pb = ProtoBuffer.init()
  for m in u.append:
    let msgPb = wire.encode(m)
    pb.write(1, msgPb.buffer)
@ -310,7 +309,7 @@ proc encode*(u: HistoryUpdate): ProtoBuffer =
  pb

 proc decode*(T: type HistoryUpdate, buf: seq[byte]): ProtobufResult[T] =
-  let pb = initProtoBuffer(buf)
+  let pb = ProtoBuffer.init(buf)
  var u = HistoryUpdate.init()
  var appBufs: seq[seq[byte]]
  discard pb.getRepeatedField(1, appBufs)
--- a/sds/types/protobuf_error.nim
+++ b/sds/types/protobuf_error.nim
@ -1,7 +1,18 @@
 import results
-import libp2p/protobuf/minprotobuf

 type
+  ProtoError* {.pure.} = enum
+    ## Low-level protobuf wire decode errors surfaced by the field codec in
+    ## `sds/protobufutil.nim`.
+    VarintDecode
+    MessageIncomplete
+    BufferOverflow
+    BadWireType
+    IncorrectBlob
+    RequiredFieldMissing
+
+  ProtoResult*[T] = Result[T, ProtoError]
+
  ProtobufErrorKind* {.pure.} = enum
    DecodeFailure
    MissingRequiredField
@ -9,13 +20,13 @@ type
  ProtobufError* = object
    case kind*: ProtobufErrorKind
    of DecodeFailure:
-      error*: minprotobuf.ProtoError
+      error*: ProtoError
    of MissingRequiredField:
      field*: string

  ProtobufResult*[T] = Result[T, ProtobufError]

-proc init*(T: type ProtobufError, error: minprotobuf.ProtoError): T =
+proc init*(T: type ProtobufError, error: ProtoError): T =
  return T(kind: ProtobufErrorKind.DecodeFailure, error: error)

 proc init*(T: type ProtobufError, field: string): T =