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write SwitchToSnapShot

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This commit is contained in:
happyZYM
2024-05-05 13:50:16 +00:00
parent c59775c184
commit 389a8b48a7
6 changed files with 271 additions and 4 deletions
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83
dataguard/src/snapshot.cpp
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@ -333,14 +333,15 @@ void SnapShotManager::CreateSnapShot(const std::string &snap_shot_ID) {
sjtu::vector<std::pair<std::string, std::string>> snapshot_relationship;
std::string cur, anc;
sjtu::map<std::string, sjtu::vector<std::string>> son_list;
sjtu::map<std::string, std::string> get_anc;
while (fs >> cur >> anc) {
snapshot_relationship.push_back({cur, anc});
son_list[anc].push_back(cur);
get_anc[cur] = anc;
}
if (son_list.find(snap_shot_ID) != son_list.end()) {
if (son_list.find(snap_shot_ID) != son_list.end() || get_anc.find(snap_shot_ID) != get_anc.end()) {
throw std::runtime_error("Snapshot already exists");
}
// TODO
fs.close();
fs.open(meta_file, std::ios::in | std::ios::out);
fs << snap_shot_ID << '\n';
@ -359,4 +360,82 @@ void SnapShotManager::CreateSnapShot(const std::string &snap_shot_ID) {
CopyFile(files[j].path, frontier_file);
}
}
}
void SnapShotManager::CheckOutFrontier() {
if (!has_set_meta_file) {
throw std::runtime_error("SnapShotManager has not set the meta file");
}
if (!has_connected) {
throw std::runtime_error("SnapShotManager has not connected to the data drivers");
}
if (logger_ptr) {
logger_ptr->info("Checking out frontier");
}
std::fstream fs(meta_file, std::ios::in);
std::string HEAD;
fs >> HEAD;
for (size_t i = 0; i < drivers.size(); i++) {
drivers[i]->Flush();
drivers[i]->LockDownForCheckOut();
if (logger_ptr) {
logger_ptr->info("flushed and locked down driver {}", i);
}
sjtu::vector<DataDriverBase::FileEntry> files = drivers[i]->ListFiles();
for (size_t j = 0; j < files.size(); j++) {
if (HEAD == "INIT") {
remove(files[j].path.c_str());
continue;
}
std::string frontier_file = files[j].path + ".frontier";
// then overwrite the frontier file
CopyFile(frontier_file, files[j].path);
}
}
}
void SnapShotManager::SwitchToSnapShot(const std::string &snap_shot_ID) {
if (!has_set_meta_file) {
throw std::runtime_error("SnapShotManager has not set the meta file");
}
if (!has_connected) {
throw std::runtime_error("SnapShotManager has not connected to the data drivers");
}
if (logger_ptr) {
logger_ptr->info("Try switching to snapshot {}", snap_shot_ID);
}
sjtu::vector<WayEntry> way = std::move(FindWay(snap_shot_ID));
if (logger_ptr) {
logger_ptr->info("Successfully found the way");
}
for (size_t i = 0; i < drivers.size(); i++) {
drivers[i]->Flush();
sjtu::vector<DataDriverBase::FileEntry> files = drivers[i]->ListFiles();
for (size_t j = 0; j < files.size(); j++) {
std::string frontier_file = files[j].path + ".frontier";
if (logger_ptr) {
logger_ptr->info("applying changes to {}", frontier_file);
}
ApplyLongChange(frontier_file, frontier_file + ".tmp", way, files[j].path);
remove(frontier_file.c_str());
rename((frontier_file + ".tmp").c_str(), frontier_file.c_str());
if (logger_ptr) {
logger_ptr->info("successfully applied changes to {}", frontier_file);
}
}
}
std::fstream fs(meta_file, std::ios::in | std::ios::out);
std::string HEAD;
fs >> HEAD;
sjtu::vector<std::pair<std::string, std::string>> snapshot_relationship;
std::string cur, anc;
while (fs >> cur >> anc) {
snapshot_relationship.push_back({cur, anc});
}
fs.close();
fs.open(meta_file, std::ios::in | std::ios::out);
fs << snap_shot_ID << '\n';
for (size_t i = 0; i < snapshot_relationship.size(); i++) {
fs << snapshot_relationship[i].first << ' ' << snapshot_relationship[i].second << '\n';
}
}