add ops, start on text diffing and op gernation, no diffing yet

This commit is contained in:
Green Sky 2022-12-14 14:56:54 +01:00
parent cf91dfb61e
commit 04b5ed7c4f
No known key found for this signature in database
2 changed files with 142 additions and 1 deletions

View File

@ -35,6 +35,20 @@ struct List {
} }
}; };
// almost the same as entry
struct OpAdd {
ListID id;
std::optional<ListID> parent_left;
std::optional<ListID> parent_right;
ValueType value;
};
struct OpDel {
ListID id;
};
// TODO: replace with SoA // TODO: replace with SoA
struct Entry { struct Entry {
ListID id; ListID id;

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@ -2,6 +2,10 @@
#include "./list.hpp" #include "./list.hpp"
#include <optional>
#include <variant>
#include <vector>
namespace GreenCRDT { namespace GreenCRDT {
template<typename AgentType> template<typename AgentType>
@ -9,14 +13,18 @@ struct TextDocument {
// TODO: determine if char is the best // TODO: determine if char is the best
using ListType = List<char, AgentType>; using ListType = List<char, AgentType>;
using Op = std::variant<typename ListType::OpAdd, typename ListType::OpDel>;
struct Cursor { struct Cursor {
AgentType who; AgentType who;
typename ListType::ListID pos; typename ListType::ListID pos;
}; };
AgentType local_agent;
ListType state; ListType state;
std::string getText(void) { [[nodiscard]] std::string getText(void) const {
std::string text; std::string text;
for (const auto& it : state.list) { for (const auto& it : state.list) {
@ -27,6 +35,125 @@ struct TextDocument {
return text; return text;
} }
static std::vector<Op> text2adds(
const AgentType& agent, uint64_t& last_seq,
std::optional<typename ListType::ListID> parent_left,
std::optional<typename ListType::ListID> parent_right,
std::string_view text
) {
std::vector<Op> ops;
for (size_t i = 0; i < text.size(); i++) {
typename ListType::ListID new_id {agent, ++last_seq};
ops.emplace_back(typename ListType::OpAdd{
new_id,
parent_left,
parent_right,
text[i]
});
parent_left = new_id;
}
return ops;
}
// adds in tast with specified parents
// returns generated ops
std::vector<Op> addText(
std::optional<typename ListType::ListID> parent_left,
std::optional<typename ListType::ListID> parent_right,
std::string_view text
) {
// TODO: look up typesystem and fix (move? decltype?)
std::vector<Op> ops = text2adds(
local_agent, state.last_seen_seq[local_agent],
parent_left,
parent_right,
text
);
// TODO: make this better
// and apply
for (const auto& op : ops) {
if constexpr (std::holds_alternative<typename ListType::OpAdd>(op)) {
const auto& add_op = std::get<typename ListType::OpAdd>(op);
state.add(add_op.id, add_op.value, add_op.parent_left, add_op.parent_right);
} else if constexpr (std::holds_alternative<typename ListType::OpDel>(op)) {
const auto& del_op = std::get<typename ListType::OpDel>(op);
state.del(del_op.id);
} else {
assert(false);
}
}
return ops; // TODO: move?
}
// deletes everything in range [first, last)
// returns generated ops
std::vector<Op> delRange(
std::optional<typename ListType::ListID> left,
std::optional<typename ListType::ListID> right
) {
size_t first_idx = 0;
if (left.has_value()) {
auto res = state.findIdx(left.value());
if (!res.has_value()) {
assert(false && "cant find left");
return {};
}
first_idx = res;
}
size_t last_idx = state.list.size();
if (right.has_value()) {
auto res = state.findIdx(right.value());
if (!res.has_value()) {
assert(false && "cant find right");
return {};
}
last_idx = res;
}
std::vector<Op> ops;
for (size_t i = first_idx; i < last_idx; i++) {
ops.emplace_back(typename ListType::OpDel{
state.list[i].id
});
// TODO: do delets get a seq?????
state.list[i].value = std::nullopt;
}
return ops;
}
// generates ops from the difference
// note: rn it only creates 1 diff patch
std::vector<Op> merge(std::string_view other_text) {
if (other_text.empty()) {
return {};
}
if (state.list.empty()) {
return addText(
std::nullopt,
std::nullopt,
other_text
);
}
// find start and end of changes
// start
size_t list_idx_start = 0;
size_t other_idx_start = 0;
//for (; idx_start < state.list.size(); idx_start++) {}
}
}; };
} // GreenCRDT } // GreenCRDT