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get rid of IdListResponse to simplify protocol

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This commit is contained in:
Doug Hoyte 2023-08-11 15:03:24 -04:00
parent a1b6eed1a4
commit fd33c9a8b2
1 changed files with 9 additions and 40 deletions
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49
cpp/Negentropy.h
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@ -136,7 +136,7 @@ struct Negentropy {
while (query.size()) { while (query.size()) {
auto currBound = decodeBound(query, lastTimestampIn); auto currBound = decodeBound(query, lastTimestampIn);
auto mode = decodeVarInt(query); // 0 = Skip, 1 = Fingerprint, 2 = IdList, 3 = IdListResponse auto mode = decodeVarInt(query); // 0 = Skip, 1 = Fingerprint, 2 = IdList
auto lower = prevIndex; auto lower = prevIndex;
auto upper = std::upper_bound(prevIndex, items.end(), currBound); auto upper = std::upper_bound(prevIndex, items.end(), currBound);
@ -166,16 +166,12 @@ struct Negentropy {
theirElems.emplace(e, TheirElem{i, false}); theirElems.emplace(e, TheirElem{i, false});
} }
std::vector<std::string> responseHaveIds;
std::vector<uint64_t> responseNeedIndices;
for (auto it = lower; it < upper; ++it) { for (auto it = lower; it < upper; ++it) {
auto e = theirElems.find(std::string(it->getId())); auto e = theirElems.find(std::string(it->getId()));
if (e == theirElems.end()) { if (e == theirElems.end()) {
// ID exists on our side, but not their side // ID exists on our side, but not their side
if (isInitiator) haveIds.emplace_back(it->getId()); if (isInitiator) haveIds.emplace_back(it->getId());
else responseHaveIds.emplace_back(it->getId());
} else { } else {
// ID exists on both sides // ID exists on both sides
e->second.onBothSides = true; e->second.onBothSides = true;
@ -186,36 +182,23 @@ struct Negentropy {
if (!v.onBothSides) { if (!v.onBothSides) {
// ID exists on their side, but not our side // ID exists on their side, but not our side
if (isInitiator) needIds.emplace_back(k); if (isInitiator) needIds.emplace_back(k);
else responseNeedIndices.emplace_back(v.offset);
} }
} }
if (!isInitiator) { if (!isInitiator) {
std::string payload = encodeVarInt(3); // mode = IdListResponse std::vector<std::string> responseHaveIds;
for (auto it = lower; it < upper; ++it) {
responseHaveIds.emplace_back(it->getId());
}
std::string payload = encodeVarInt(2); // mode = IdList
payload += encodeVarInt(responseHaveIds.size()); payload += encodeVarInt(responseHaveIds.size());
for (const auto &id : responseHaveIds) payload += id; for (const auto &id : responseHaveIds) payload += id;
auto bitField = encodeBitField(responseNeedIndices);
payload += encodeVarInt(bitField.size());
payload += bitField;
outputs.emplace_back(BoundOutput({ prevBound, currBound, std::move(payload) })); outputs.emplace_back(BoundOutput({ prevBound, currBound, std::move(payload) }));
} }
} else if (mode == 3) { // IdListResponse
if (!isInitiator) throw negentropy::err("unexpected IdListResponse");
auto numIds = decodeVarInt(query);
for (uint64_t i = 0; i < numIds; i++) {
needIds.emplace_back(getBytes(query, idSize));
}
auto bitFieldSize = decodeVarInt(query);
auto bitField = getBytes(query, bitFieldSize);
for (auto it = lower; it < upper; ++it) {
if (bitFieldLookup(bitField, it - lower)) haveIds.emplace_back(it->getId());
}
} else { } else {
throw negentropy::err("unexpected mode"); throw negentropy::err("unexpected mode");
} }
@ -298,6 +281,7 @@ struct Negentropy {
return output; return output;
} }
// Decoding // Decoding
std::string getBytes(std::string_view &encoded, size_t n) { std::string getBytes(std::string_view &encoded, size_t n) {
@ -396,21 +380,6 @@ struct Negentropy {
return XorElem(curr.timestamp, currKey.substr(0, sharedPrefixBytes + 1)); return XorElem(curr.timestamp, currKey.substr(0, sharedPrefixBytes + 1));
} }
} }
std::string encodeBitField(const std::vector<uint64_t> inds) {
if (inds.size() == 0) return "";
uint64_t max = *std::max_element(inds.begin(), inds.end());
std::string bitField = std::string((max + 8) / 8, '\0');
for (auto ind : inds) bitField[ind / 8] |= 1 << ind % 8;
return bitField;
}
bool bitFieldLookup(const std::string &bitField, uint64_t ind) {
if ((ind + 8) / 8 > bitField.size()) return false;
return !!(bitField[ind / 8] & 1 << (ind % 8));
}
}; };