start on test2, YjsMod style list

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Green Sky 2022-12-12 15:49:49 +01:00
parent 1e3b42bb44
commit a05e301e9b
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2 changed files with 385 additions and 0 deletions

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@ -45,3 +45,15 @@ target_link_libraries(test1 PUBLIC
nlohmann_json::nlohmann_json nlohmann_json::nlohmann_json
) )
########################################
add_executable(test2
./test2.cpp
)
target_compile_features(test2 PUBLIC cxx_std_17)
target_link_libraries(test2 PUBLIC
nlohmann_json::nlohmann_json
)

373
test2.cpp Normal file
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@ -0,0 +1,373 @@
#include <array>
#include <list>
#include <optional>
#include <vector>
#include <map>
#include <iostream>
#include <cassert>
namespace GreenCRDT {
namespace detail {
uint8_t nib_from_hex(char c) {
assert((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f'));
if (c >= '0' && c <= '9') {
return static_cast<uint8_t>(c) - '0';
} else if (c >= 'a' && c <= 'f') {
return (static_cast<uint8_t>(c) - 'a') + 10u;
} else {
return 0u;
}
}
} // detail
struct ID {
// something like a toxid
// for testing its martins paper trace
std::array<uint8_t, 32> data;
bool operator<(const ID& rhs) const {
return data < rhs.data;
}
bool operator==(const ID& rhs) const {
return data == rhs.data;
}
bool operator!=(const ID& rhs) const {
return data != rhs.data;
}
static ID fromHex(const std::string_view str) {
assert(str.size() == 32*2);
ID tmp;
for (size_t i = 0; i < tmp.data.size(); i++) {
tmp.data[i] = detail::nib_from_hex(str[i*2]) << 4 | detail::nib_from_hex(str[i*2+1]);
}
return tmp;
}
};
using Agent = ID;
struct ListID {
Agent id;
uint64_t seq{0}; // strictly increasing for that agent
bool operator<(const ListID& rhs) const {
if (seq < rhs.seq) {
return true;
} else if (seq > rhs.seq) {
return false;
} else { // ==
return id < rhs.id;
}
}
bool operator==(const ListID& rhs) const {
return seq == rhs.seq && id == rhs.id;
}
bool operator!=(const ListID& rhs) const {
return seq != rhs.seq || id != rhs.id;
}
static ListID fromStr(const std::string_view str) {
assert(str.size() >= 32*2);
size_t at_pos = str.find_first_of('@');
const auto seq_sv = str.substr(0, at_pos);
const auto agent_sv = str.substr(at_pos+1);
assert(seq_sv.size() != 0);
assert(agent_sv.size() == 32*2);
uint64_t tmp_seq {0};
for (size_t i = 0; i < seq_sv.size(); i++) {
assert(seq_sv[i] >= '0' && seq_sv[i] <= '9');
tmp_seq *= 10;
tmp_seq += seq_sv[i] - '0';
}
return {GreenCRDT::Agent::fromHex(agent_sv), tmp_seq};
}
};
template<typename ValueType>
struct List {
// TODO: replace with SoA
struct Entry {
ListID id;
// Yjs
std::optional<ListID> parent_left;
std::optional<ListID> parent_right;
// might be deleted (yes, *sigh*, crtds need tombstones)
std::optional<ValueType> value;
};
// linked list for now
std::list<Entry> list;
// number of not deleted entries
size_t doc_size {0};
std::map<Agent, uint64_t> last_seen_seq;
auto find(const ListID& list_id) {
auto it = list.begin();
for (; it != list.end(); it++) {
if (it->id == list_id) {
break;
}
}
return it;
}
// returns false if parent not found. (missing OPs)
// returns false if missing operations
// base on YjsMod https://github.com/josephg/reference-crdts/blob/9f4f9c3a97b497e2df8ae4473d1e521d3c3bf2d2/crdts.ts#L293-L348
// which is a modified Yjs algo
bool add(const ListID& list_id, const ValueType& value, const std::optional<ListID>& parent_left, const std::optional<ListID>& parent_right) {
// check agent op order
if (!last_seen_seq.count(list_id.id)) {
// we dont know this agent yet, first seq needs to be 0
if (list_id.seq != 0) {
return false;
}
} else {
// making sure we dont skip operations by that agent
if (list_id.seq != last_seen_seq.at(list_id.id) + 1) {
return false;
}
}
if (list.empty()) {
if (parent_left.has_value() || parent_right.has_value()) {
// empty, missing parents
return false;
}
list.emplace(list.begin(), Entry{
list_id,
parent_left,
parent_right,
value
});
// insert parentless into empty doc
} else {
// find left
auto left_it = list.begin();
if (parent_left.has_value()) {
left_it = find(parent_left.value());
if (left_it == list.end()) {
// missing parent left
return false;
}
left_it++; // we insert before the it, so we need to go past the left parent
}
// left_it is not at the first potential insert position
// find right
auto right_it = list.end();
if (parent_right.has_value()) {
right_it = find(parent_right.value());
if (right_it == list.end()) {
// missing parent right
return false;
}
}
do {
// if rightmost / end of doc, insert
if (left_it == right_it) {
break;
}
} while (true);
list.emplace(left_it, Entry{
list_id,
parent_left,
parent_right,
value
});
}
doc_size++;
last_seen_seq[list_id.id] = list_id.seq;
return true;
}
// returns false if not found
bool del(const ListID& id) {
auto it = list.begin();
for (; it != list.end(); it++) {
if (it->id == id) {
it->value = std::nullopt;
assert(doc_size > 0);
doc_size--;
return true;
}
}
// not found
return false;
}
};
struct TextDocument {
struct Cursor {
Agent who;
ListID pos;
};
// TODO: determine if char is the best
List<char> state;
friend std::ostream& operator<<(std::ostream& out, const TextDocument& doc) {
// simple print
for (const auto& it : doc.state.list) {
if (it.value) {
out << it.value.value();
}
}
return out;
}
std::string getText(void) {
std::string text;
for (const auto& it : state.list) {
if (it.value) {
text += it.value.value();
}
}
return text;
}
};
} // GreenCRDT
void testSingle1(void) {
GreenCRDT::TextDocument doc;
const auto agent_a = GreenCRDT::Agent::fromHex("0a00000000000000000000000000000000000000000000000000000000000000");
doc.state.add({agent_a, 0}, 'a', std::nullopt, std::nullopt);
doc.state.add({agent_a, 1}, 'b', GreenCRDT::ListID{agent_a, 0u}, std::nullopt);
assert(doc.getText() == "ab");
}
void testConcurrent1(void) {
const auto agent_a = GreenCRDT::Agent::fromHex("0a00000000000000000000000000000000000000000000000000000000000000");
const auto agent_b = GreenCRDT::Agent::fromHex("0b00000000000000000000000000000000000000000000000000000000000000");
// agent_a < agent_b
// concurrent insert of first element
{ // variant 1, a then b
GreenCRDT::TextDocument doc;
doc.state.add({agent_a, 0}, 'a', std::nullopt, std::nullopt);
doc.state.add({agent_b, 0}, 'b', std::nullopt, std::nullopt);
assert(doc.getText() == "ab");
}
{ // variant 2, b then a
GreenCRDT::TextDocument doc;
doc.state.add({agent_b, 0}, 'b', std::nullopt, std::nullopt);
doc.state.add({agent_a, 0}, 'a', std::nullopt, std::nullopt);
assert(doc.getText() == "ab");
}
}
void testMain1(void) {
GreenCRDT::TextDocument doc;
const GreenCRDT::Agent agent0 = GreenCRDT::Agent::fromHex("9654bd415cfac9ee6aa9f55bf1024f840afdbb1f37237673c928491a91ff7783");
uint64_t agent0_seq {0};
const GreenCRDT::Agent agent1 = GreenCRDT::Agent::fromHex("0100000000000000000000000000000000000000000000000000000000000000");
uint64_t agent1_seq {0};
struct AddOp {
GreenCRDT::ListID id;
char value;
std::optional<GreenCRDT::ListID> parent_left;
std::optional<GreenCRDT::ListID> parent_right;
};
const std::vector<AddOp> a0_ops {
{{agent0, agent0_seq++}, 'a', std::nullopt, std::nullopt},
{{agent0, agent0_seq++}, 'b', GreenCRDT::ListID{agent0, 0u}, std::nullopt},
{{agent0, agent0_seq++}, 'c', GreenCRDT::ListID{agent0, 1u}, std::nullopt},
{{agent0, agent0_seq++}, 'd', GreenCRDT::ListID{agent0, 1u}, GreenCRDT::ListID{agent0, 2u}},
};
const std::vector<AddOp> a1_ops {
// knows of a0 up to {a0, 1}
{{agent1, agent1_seq++}, 'z', GreenCRDT::ListID{agent0, 0u}, GreenCRDT::ListID{agent0, 1u}},
{{agent1, agent1_seq++}, 'y', GreenCRDT::ListID{agent0, 1u}, std::nullopt},
};
{ // the ez, in order stuff
// a0 insert first char, 'a', since its the first, we dont have any parents
doc.state.add(a0_ops[0].id, a0_ops[0].value, a0_ops[0].parent_left, a0_ops[0].parent_right);
assert(doc.getText() == "a");
// a0 insert secound char, 'b' after 'a', no parents to right
doc.state.add(a0_ops[1].id, a0_ops[1].value, a0_ops[1].parent_left, a0_ops[1].parent_right);
assert(doc.getText() == "ab");
// a0 insert 'c' after 'b', no parents to right
doc.state.add(a0_ops[2].id, a0_ops[2].value, a0_ops[2].parent_left, a0_ops[2].parent_right);
assert(doc.getText() == "abc");
// a0 insert 'd' after 'b', 'c' parent right
doc.state.add(a0_ops[3].id, a0_ops[3].value, a0_ops[3].parent_left, a0_ops[3].parent_right);
assert(doc.getText() == "abdc");
// a1 insert 'z' after 'a', 'b' parent right
doc.state.add(a1_ops[0].id, a1_ops[0].value, a1_ops[0].parent_left, a1_ops[0].parent_right);
assert(doc.getText() == "azbdc");
}
std::cout << "done with ez\n";
{ // a1 was not uptodate only had 0,1 of a0
// a1 insert 'y' after 'b', no parent right
doc.state.add(a1_ops[1].id, a1_ops[1].value, a1_ops[1].parent_left, a1_ops[1].parent_right);
assert(doc.getText() == "azbydc");
}
std::cout << "\ndoc size (with tombstones): " << doc.state.list.size() << "\n";
std::cout << "\ndoc size: " << doc.state.doc_size << "\n";
std::cout << "doc text:\n";
// simple print
std::cout << doc << "\n";
}
int main(void) {
std::cout << "testSingle1:\n";
testSingle1();
std::cout << std::string(40, '-') << "\n";
std::cout << "testConcurrent1:\n";
testConcurrent1();
std::cout << std::string(40, '-') << "\n";
std::cout << "testMain1:\n";
testMain1();
std::cout << std::string(40, '-') << "\n";
return 0;
}