// Copyright 2019 Roman Perepelitsa.
//
// This file is part of GitStatus.
//
// GitStatus is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GitStatus is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with GitStatus. If not, see <https://www.gnu.org/licenses/>.
#include "repo_cache.h"
#include <cstring>
#include "check.h"
#include "git.h"
#include "print.h"
#include "scope_guard.h"
#include "string_view.h"
namespace gitstatus {
namespace {
void GitDirs(const char* dir, bool from_dotgit, std::string& gitdir, std::string& workdir) {
git_buf gitdir_buf = {};
git_buf workdir_buf = {};
ON_SCOPE_EXIT(&) {
git_buf_free(&gitdir_buf);
git_buf_free(&workdir_buf);
};
int flags = from_dotgit ? GIT_REPOSITORY_OPEN_NO_SEARCH | GIT_REPOSITORY_OPEN_NO_DOTGIT : 0;
switch (git_repository_discover_ex(&gitdir_buf, &workdir_buf, NULL, NULL, dir, flags, nullptr)) {
case 0:
gitdir.assign(gitdir_buf.ptr, gitdir_buf.size);
workdir.assign(workdir_buf.ptr, workdir_buf.size);
VERIFY(!gitdir.empty() && gitdir.front() == '/' && gitdir.back() == '/');
VERIFY(!workdir.empty() && workdir.front() == '/' && workdir.back() == '/');
break;
case GIT_ENOTFOUND:
gitdir.clear();
workdir.clear();
break;
default:
LOG(ERROR) << "git_repository_open_ext: " << Print(dir) << ": " << GitError();
throw Exception();
}
}
git_repository* OpenRepo(const std::string& dir, bool from_dotgit) {
git_repository* repo = nullptr;
int flags = from_dotgit ? GIT_REPOSITORY_OPEN_NO_SEARCH | GIT_REPOSITORY_OPEN_NO_DOTGIT : 0;
switch (git_repository_open_ext(&repo, dir.c_str(), flags, nullptr)) {
case 0:
return repo;
case GIT_ENOTFOUND:
return nullptr;
default:
LOG(ERROR) << "git_repository_open_ext: " << Print(dir) << ": " << GitError();
throw Exception();
}
}
std::string DirName(std::string path) {
if (path.empty()) return "";
while (path.back() == '/') {
path.pop_back();
if (path.empty()) return "";
}
do {
path.pop_back();
if (path.empty()) return "";
} while (path.back() != '/');
return path;
}
} // namespace
Repo* RepoCache::Open(const std::string& dir, bool from_dotgit) {
if (dir.empty() || dir.front() != '/') return nullptr;
std::string gitdir, workdir;
GitDirs(dir.c_str(), from_dotgit, gitdir, workdir);
if (gitdir.empty()) {
// This isn't quite correct because of differences in canonicalization, .git files and GIT_DIR.
// A proper solution would require tracking the "discovery dir" for every repository and
// performing path canonicalization.
if (from_dotgit) {
Erase(cache_.find(dir.back() == '/' ? dir : dir + '/'));
} else {
std::string path = dir;
if (path.back() != '/') path += '/';
do {
Erase(cache_.find(path + ".git/"));
path = DirName(path);
} while (!path.empty());
}
return nullptr;
}
auto it = cache_.find(gitdir);
if (it != cache_.end()) {
lru_.erase(it->second->lru);
it->second->lru = lru_.insert({Clock::now(), it});
return it->second.get();
}
// Opening from gitdir is faster but we cannot use it when gitdir came from a .git file.
git_repository* repo =
DirName(gitdir) == workdir ? OpenRepo(gitdir, true) : OpenRepo(dir, from_dotgit);
if (!repo) return nullptr;
ON_SCOPE_EXIT(&) {
if (repo) git_repository_free(repo);
};
if (git_repository_is_bare(repo)) return nullptr;
workdir = git_repository_workdir(repo) ?: "";
if (workdir.empty()) return nullptr;
VERIFY(workdir.front() == '/' && workdir.back() == '/') << Print(workdir);
auto x = cache_.emplace(gitdir, nullptr);
std::unique_ptr<Entry>& elem = x.first->second;
if (elem) {
lru_.erase(elem->lru);
} else {
LOG(INFO) << "Initializing new repository: " << Print(gitdir);
// Libgit2 initializes odb and refdb lazily with double-locking. To avoid useless work
// when multiple threads attempt to initialize the same db at the same time, we trigger
// initialization manually before threads are in play.
git_odb* odb;
VERIFY(!git_repository_odb(&odb, repo)) << GitError();
git_odb_free(odb);
git_refdb* refdb;
VERIFY(!git_repository_refdb(&refdb, repo)) << GitError();
git_refdb_free(refdb);
elem = std::make_unique<Entry>(std::exchange(repo, nullptr), lim_);
}
elem->lru = lru_.insert({Clock::now(), x.first});
return elem.get();
}
void RepoCache::Free(Time cutoff) {
while (true) {
if (lru_.empty()) break;
auto it = lru_.begin();
if (it->first > cutoff) break;
Erase(it->second);
}
}
void RepoCache::Erase(Cache::iterator it) {
if (it == cache_.end()) return;
LOG(INFO) << "Closing repository: " << Print(it->first);
lru_.erase(it->second->lru);
cache_.erase(it);
}
} // namespace gitstatus
