basic lightly tested v1, only change from v0 to v1 is actor cache (way lighter for large actor ids)

CMakeLists.txt

@@ -38,6 +38,7 @@ endif()
 add_subdirectory(./prototyping EXCLUDE_FROM_ALL)
 
 add_subdirectory(./version0)
+add_subdirectory(./version1)
 
 add_subdirectory(./bench)
 

version1/CMakeLists.txt

@@ -0,0 +1,26 @@
+cmake_minimum_required(VERSION 3.9 FATAL_ERROR)
+
+project(crdt_version1 CXX C)
+
+add_library(crdt_version1 INTERFACE)
+
+target_compile_features(crdt_version1 INTERFACE cxx_std_17)
+
+target_include_directories(crdt_version1 INTERFACE "${PROJECT_SOURCE_DIR}")
+
+########################################
+
+add_executable(v1_test1
+	./test1.cpp
+)
+
+target_link_libraries(v1_test1 PUBLIC crdt_version1)
+
+########################################
+
+#add_executable(v1_test2
+	#./test2.cpp
+#)
+
+#target_link_libraries(v1_test2 PUBLIC crdt_version1)
+

version1/green_crdt/v1/list.hpp

@@ -0,0 +1,328 @@
+#pragma once
+
+#include <cstdint>
+#include <optional>
+#include <vector>
+#include <map>
+#include <string>
+
+#include <cassert>
+
+#if !defined(extra_assert)
+	#if defined(EXTRA_ASSERTS) && EXTRA_ASSERTS == 1
+		#define extra_assert(...) assert(__VA_ARGS__)
+	#else
+		#define extra_assert(...) void(0)
+	#endif
+#endif
+
+namespace GreenCRDT::V1 {
+
+template<typename ValueType, typename ActorType>
+struct List {
+	// for public interface
+	struct ListID {
+		ActorType id;
+		uint64_t seq{0}; // strictly increasing for that actor
+
+		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;
+		}
+	};
+
+	struct ListIDInternal {
+		size_t actor_idx{0};
+		uint64_t seq{0}; // strictly increasing for that actor
+
+		bool operator==(const ListIDInternal& rhs) const {
+			return seq == rhs.seq && actor_idx == rhs.actor_idx;
+		}
+	};
+
+	// internally the index into this array is used to refer to an actor
+	std::vector<ActorType> _actors;
+
+	// TODO: replace with SoA
+	struct Entry {
+		ListIDInternal id;
+
+		// Yjs
+		std::optional<ListIDInternal> parent_left;
+		std::optional<ListIDInternal> parent_right;
+
+		// might be deleted (yes, *sigh*, crtds need tombstones)
+		std::optional<ValueType> value;
+	};
+
+	// TODO: use something better, edit: this seems fine
+	std::vector<Entry> list;
+
+	// number of not deleted entries
+	size_t doc_size {0};
+
+	std::map<size_t, uint64_t> last_seen_seq;
+
+	std::optional<size_t> findActor(const ActorType& actor) const {
+		for (size_t i = 0; i < _actors.size(); i++) {
+			if (_actors[i] == actor) {
+				return i;
+			}
+		}
+		return std::nullopt;
+	}
+
+	std::optional<size_t> findIdx(const ListIDInternal& list_id) const {
+		extra_assert(verify());
+
+		for (size_t i = 0; i < list.size(); i++) {
+			if (list[i].id == list_id) {
+				return i;
+			}
+		}
+
+		return std::nullopt;
+	}
+
+	std::optional<size_t> findIdx(const ListID& list_id) const {
+		extra_assert(verify());
+
+		const auto actor_idx_opt = findActor(list_id.id);
+		if (!actor_idx_opt.has_value()) {
+			return std::nullopt;
+		}
+
+		const ListIDInternal tmp_id {actor_idx_opt.value(), list_id.seq};
+
+		for (size_t i = 0; i < list.size(); i++) {
+			if (list[i].id == tmp_id) {
+				return i;
+			}
+		}
+
+		return std::nullopt;
+	}
+
+	// returns false if missing OPs
+	// based on YjsMod https://github.com/josephg/reference-crdts/blob/9f4f9c3a97b497e2df8ae4473d1e521d3c3bf2d2/crdts.ts#L293-L348
+	// which is a modified Yjs(YATA) algo
+	bool add(const ListID& list_id, const ValueType& value, const std::optional<ListID>& parent_left, const std::optional<ListID>& parent_right) {
+		extra_assert(verify());
+
+		size_t actor_idx {0};
+		{ // new actor?
+			// add, even if op fails
+			const auto actor_opt = findActor(list_id.id);
+			if (!actor_opt.has_value()) {
+				actor_idx = _actors.size();
+				_actors.push_back(list_id.id);
+			} else {
+				actor_idx = actor_opt.value();
+			}
+		}
+
+		// check actor op order
+		if (!last_seen_seq.count(actor_idx)) {
+			// we dont know this actor yet, first seq needs to be 0
+			if (list_id.seq != 0) {
+				return false;
+			}
+		} else {
+			// making sure we dont skip operations by that actor
+			if (list_id.seq != last_seen_seq.at(actor_idx) + 1) {
+				return false;
+			}
+		}
+
+		size_t insert_idx = 0;
+		if (list.empty()) {
+			if (parent_left.has_value() || parent_right.has_value()) {
+				// empty, missing parents
+				return false;
+			}
+		} else {
+			// find left
+			std::optional<size_t> left_idx = std::nullopt;
+			if (parent_left.has_value()) {
+				left_idx = findIdx(parent_left.value());
+				if (!left_idx.has_value()) {
+					// missing parent left
+					return false;
+				}
+
+				// we insert before the it, so we need to go past the left parent
+				insert_idx = left_idx.value() + 1;
+			} // else insert_idx = 0
+
+			// find right
+			size_t right_idx = list.size();
+			if (parent_right.has_value()) {
+				auto tmp_right = findIdx(parent_right.value());
+				if (!tmp_right.has_value()) {
+					return false;
+				}
+				right_idx = tmp_right.value();
+			}
+
+			bool scanning {false};
+
+			for(size_t i = insert_idx;; i++) {
+				if (!scanning) {
+					insert_idx = i;
+				}
+				// if right parent / end of doc, insert
+				if (insert_idx == right_idx) {
+					break;
+				}
+				// we ran past right o.o ?
+				if (insert_idx == list.size()) {
+					break;
+				}
+
+				const Entry& at_i = list[i];
+				// parents left and right
+				std::optional<size_t> i_left_idx {std::nullopt};
+				if (at_i.parent_left.has_value()) {
+					i_left_idx = findIdx(at_i.parent_left.value());
+					if (!i_left_idx.has_value()) {
+						assert(false && "item in list with unknown parent left!!");
+						return false;
+					}
+				}
+
+				// possibility map
+				//
+				//         | ir < r | ir == r       | ir > r
+				// -------------------------------------
+				// il < l  | insert | insert        | insert
+				// il == l | ?      | agentfallback | ?
+				// il > l  | skip   | skip          | skip
+
+				if (i_left_idx < left_idx) {
+					break;
+				} else if (i_left_idx == left_idx) {
+					// get i parent_right
+					size_t i_right_idx = list.size();
+					if (at_i.parent_right.has_value()) {
+						auto tmp_right = findIdx(at_i.parent_right.value());
+						if (!tmp_right.has_value()) {
+							assert(false && "item in list with unknown parent right!!");
+							return false;
+						}
+						i_right_idx = tmp_right.value();
+					}
+
+					if (i_right_idx < right_idx) {
+						scanning = true;
+					} else if (i_right_idx == right_idx) {
+						// actor id tie breaker
+						if (_actors[actor_idx] < _actors[at_i.id.actor_idx]) {
+							break;
+						} else {
+							scanning = false;
+						}
+					} else { // i_right_idx > right_idx
+						scanning = false;
+					}
+				} else { // il > l
+					// do nothing
+				}
+			}
+		}
+
+		{ // actual insert
+			Entry new_entry;
+
+			new_entry.id.actor_idx = actor_idx;
+			new_entry.id.seq = list_id.seq;
+
+			if (parent_left.has_value()) {
+				new_entry.parent_left = ListIDInternal{findActor(parent_left.value().id).value(), parent_left.value().seq};
+			}
+
+			if (parent_right.has_value()) {
+				new_entry.parent_right = ListIDInternal{findActor(parent_right.value().id).value(), parent_right.value().seq};
+			}
+
+			new_entry.value = value;
+
+			list.emplace(list.begin() + insert_idx, new_entry);
+		}
+
+		doc_size++;
+		last_seen_seq[actor_idx] = list_id.seq;
+
+		extra_assert(verify());
+		return true;
+	}
+
+	// returns false if not found
+	bool del(const ListID& id) {
+		extra_assert(verify());
+
+		auto actor_idx_opt = findActor(id.id);
+		if (!actor_idx_opt.has_value()) {
+			// we dont have anything with that actor
+			return false;
+		}
+
+		const ListIDInternal tmp_id {actor_idx_opt.value(), id.seq};
+
+		for (auto& it : list) {
+			if (it.id == tmp_id) {
+				if (it.value.has_value()) {
+					it.value.reset();
+
+					doc_size--;
+					extra_assert(verify());
+					return true;
+				} else {
+					extra_assert(verify());
+					return false; // TODO: allow double deletes?,,,, need ids
+				}
+			}
+		}
+
+		extra_assert(verify());
+		return false;
+	}
+
+	std::vector<ValueType> getArray(void) const {
+		std::vector<ValueType> array;
+		for (const auto& e : list) {
+			if (e.value.has_value()) {
+				array.push_back(e.value.value());
+			}
+		}
+
+		return array;
+	}
+
+	// TODO: only in debug?
+	bool verify(void) const {
+		size_t actual_size = 0;
+		for (const auto& it : list) {
+			if (it.value.has_value()) {
+				actual_size++;
+			}
+		}
+		//assert(doc_size == actual_size);
+		return doc_size == actual_size;
+	}
+};
+
+} // GreenCRDT::V1
+

version1/test1.cpp

@@ -0,0 +1,214 @@
+#define EXTRA_ASSERTS 1
+#include <green_crdt/v1/list.hpp>
+
+#include <numeric>
+#include <random>
+#include <iostream>
+#include <cassert>
+#include <string_view>
+#include <vector>
+
+// single letter actor, for testing only
+using Actor = char;
+using ListType = GreenCRDT::V1::List<char, Actor>;
+
+namespace std {
+bool operator==(const std::vector<char>& lhs, const std::string_view& rhs) {
+	if (lhs.size() != rhs.size()) {
+		return false;
+	}
+
+	for (size_t i = 0; i < rhs.size(); i++) {
+		if (lhs[i] != rhs[i]) {
+			return false;
+		}
+	}
+
+	return true;
+}
+} // namespace std
+
+void testSingle1(void) {
+	ListType list;
+
+	assert(list.add({'A', 0}, 'a', std::nullopt, std::nullopt));
+	assert(list.add({'A', 1}, 'b', ListType::ListID{'A', 0u}, std::nullopt));
+
+	assert(list.getArray() == "ab");
+}
+
+
+void testConcurrent1(void) {
+	// agent_a < agent_b
+
+	// concurrent insert of first element
+	{ // variant 1, a then b
+		ListType list;
+		assert(list.add({'A', 0}, 'a', std::nullopt, std::nullopt));
+		assert(list.add({'B', 0}, 'b', std::nullopt, std::nullopt));
+
+		assert(list.getArray() == "ab");
+	}
+	{ // variant 2, b then a
+		ListType list;
+		assert(list.add({'B', 0}, 'b', std::nullopt, std::nullopt));
+		assert(list.add({'A', 0}, 'a', std::nullopt, std::nullopt));
+
+		assert(list.getArray() == "ab");
+	}
+}
+
+struct AddOp {
+	ListType::ListID id;
+	char value;
+	std::optional<ListType::ListID> parent_left;
+	std::optional<ListType::ListID> parent_right;
+};
+
+void randomAddPermutations(const std::vector<AddOp>& ops, const std::string& expected) {
+	// TODO: more then 1k?
+	for (size_t i = 0; i < 1000; i++) {
+		std::minstd_rand rng(1337 + i);
+		std::vector<size_t> ops_todo(ops.size());
+		std::iota(ops_todo.begin(), ops_todo.end(), 0u);
+
+		size_t attempts {0};
+
+		ListType list;
+		do {
+			size_t idx = rng() % ops_todo.size();
+
+			if (list.add(ops[ops_todo[idx]].id, ops[ops_todo[idx]].value, ops[ops_todo[idx]].parent_left, ops[ops_todo[idx]].parent_right)) {
+				// only remove if it was possible -> returned true;
+				ops_todo.erase(ops_todo.begin()+idx);
+			}
+
+			attempts++;
+			assert(attempts < 10'000); // in case we run into an endless loop
+		} while (!ops_todo.empty());
+
+		assert(list.getArray() == expected);
+	}
+}
+
+void testInterleave1(void) {
+	const std::vector<AddOp> ops {
+		{{'A', 0u}, 'a', std::nullopt, std::nullopt},
+		{{'A', 1u}, 'a', ListType::ListID{'A', 0u}, std::nullopt},
+		{{'A', 2u}, 'a', ListType::ListID{'A', 1u}, std::nullopt},
+		{{'B', 0u}, 'b', std::nullopt, std::nullopt},
+		{{'B', 1u}, 'b', ListType::ListID{'B', 0u}, std::nullopt},
+		{{'B', 2u}, 'b', ListType::ListID{'B', 1u}, std::nullopt},
+	};
+
+	randomAddPermutations(ops, "aaabbb");
+}
+
+void testInterleave2(void) {
+	const std::vector<AddOp> ops {
+		{{'A', 0u}, 'a', std::nullopt, std::nullopt},
+		{{'A', 1u}, 'a', std::nullopt, ListType::ListID{'A', 0u}},
+		{{'A', 2u}, 'a', std::nullopt, ListType::ListID{'A', 1u}},
+		{{'B', 0u}, 'b', std::nullopt, std::nullopt},
+		{{'B', 1u}, 'b', std::nullopt, ListType::ListID{'B', 0u}},
+		{{'B', 2u}, 'b', std::nullopt, ListType::ListID{'B', 1u}},
+	};
+
+	randomAddPermutations(ops, "aaabbb");
+}
+
+void testConcurrent2(void) {
+	const std::vector<AddOp> ops {
+		{{'A', 0u}, 'a', std::nullopt, std::nullopt},
+		{{'C', 0u}, 'c', std::nullopt, std::nullopt},
+		{{'B', 0u}, 'b', std::nullopt, std::nullopt},
+		{{'D', 0u}, 'd', ListType::ListID{'A', 0u}, ListType::ListID{'C', 0u}},
+	};
+
+	randomAddPermutations(ops, "adbc");
+}
+
+void testMain1(void) {
+	ListType list;
+
+	static_assert('0' < '1');
+
+	const std::vector<AddOp> a0_ops {
+		{{'0', 0u}, 'a', std::nullopt, std::nullopt},
+		{{'0', 1u}, 'b', ListType::ListID{'0', 0u}, std::nullopt},
+		{{'0', 2u}, 'c', ListType::ListID{'0', 1u}, std::nullopt},
+		{{'0', 3u}, 'd', ListType::ListID{'0', 1u}, ListType::ListID{'0', 2u}},
+	};
+
+	const std::vector<AddOp> a1_ops {
+		// knows of a0 up to {a0, 1}
+		{{'1', 0u}, 'z', ListType::ListID{'0', 0u}, ListType::ListID{'0', 1u}},
+		{{'1', 1u}, 'y', ListType::ListID{'0', 1u}, std::nullopt},
+	};
+
+	{ // the ez, in order stuff
+		// a0 insert first char, 'a', since its the first, we dont have any parents
+		assert(list.add(a0_ops[0].id, a0_ops[0].value, a0_ops[0].parent_left, a0_ops[0].parent_right));
+		assert(list.getArray() == "a");
+
+		// a0 insert secound char, 'b' after 'a', no parents to right
+		assert(list.add(a0_ops[1].id, a0_ops[1].value, a0_ops[1].parent_left, a0_ops[1].parent_right));
+		assert(list.getArray() == "ab");
+
+		// a0 insert 'c' after 'b', no parents to right
+		assert(list.add(a0_ops[2].id, a0_ops[2].value, a0_ops[2].parent_left, a0_ops[2].parent_right));
+		assert(list.getArray() == "abc");
+
+		// a0 insert 'd' after 'b', 'c' parent right
+		assert(list.add(a0_ops[3].id, a0_ops[3].value, a0_ops[3].parent_left, a0_ops[3].parent_right));
+		assert(list.getArray() == "abdc");
+
+		// a1 insert 'z' after 'a', 'b' parent right
+		assert(list.add(a1_ops[0].id, a1_ops[0].value, a1_ops[0].parent_left, a1_ops[0].parent_right));
+		assert(list.getArray() == "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
+		assert(list.add(a1_ops[1].id, a1_ops[1].value, a1_ops[1].parent_left, a1_ops[1].parent_right));
+		assert(list.getArray() == "azbdcy");
+	}
+
+	std::cout << "\ndoc size (with tombstones): " << list.list.size() << "\n";
+	std::cout << "\ndoc size: " << list.doc_size << "\n";
+	std::cout << "doc text:\n";
+
+	const auto tmp_array = list.getArray();
+	std::cout << std::string_view(tmp_array.data(), tmp_array.size()) << "\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 << "testInterleave1:\n";
+	testInterleave1();
+	std::cout << std::string(40, '-') << "\n";
+
+	std::cout << "testInterleave2:\n";
+	testInterleave2();
+	std::cout << std::string(40, '-') << "\n";
+
+	std::cout << "testConcurrent2:\n";
+	testConcurrent2();
+	std::cout << std::string(40, '-') << "\n";
+
+	std::cout << "testMain1:\n";
+	testMain1();
+	std::cout << std::string(40, '-') << "\n";
+
+	return 0;
+}
+