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#include "src/buildtool/file_system/git_tree.hpp"
#include <sstream>
#include "src/buildtool/logging/logger.hpp"
extern "C" {
#include <git2.h>
}
namespace {
constexpr auto kOIDRawSize{GIT_OID_RAWSZ};
auto const kLoadTreeError =
std::make_shared<std::optional<GitTree>>(std::nullopt);
[[nodiscard]] auto PermToType(std::string const& perm_str) noexcept
-> std::optional<ObjectType> {
constexpr auto kPermBase = 8;
constexpr auto kTreePerm = 040000;
constexpr auto kFilePerm = 0100644;
constexpr auto kExecPerm = 0100755;
constexpr auto kLinkPerm = 0120000;
int perm = std::stoi(perm_str, nullptr, kPermBase);
switch (perm) {
case kTreePerm:
return ObjectType::Tree;
case kFilePerm:
return ObjectType::File;
case kExecPerm:
return ObjectType::Executable;
case kLinkPerm:
Logger::Log(LogLevel::Error, "symlinks are not yet supported");
return std::nullopt;
default:
Logger::Log(LogLevel::Error, "unsupported permission {}", perm_str);
return std::nullopt;
}
}
auto ParseRawTreeObject(GitCASPtr const& cas,
std::string const& raw_tree) noexcept
-> std::optional<GitTree::entries_t> {
std::string perm{};
std::string path{};
std::string hash(kOIDRawSize, '\0');
std::istringstream iss{raw_tree};
GitTree::entries_t entries{};
// raw tree format is: "<perm> <path>\0<hash>[next entries...]"
while (std::getline(iss, perm, ' ') and // <perm>
std::getline(iss, path, '\0') and // <path>
iss.read(hash.data(), // <hash>
static_cast<std::streamsize>(hash.size()))) {
auto type = PermToType(perm);
if (not type) {
return std::nullopt;
}
try {
entries.emplace(path,
std::make_shared<GitTreeEntry>(cas, hash, *type));
} catch (std::exception const& ex) {
Logger::Log(LogLevel::Error,
"parsing git raw tree object failed with:\n{}",
ex.what());
return std::nullopt;
}
}
return entries;
}
// resolve '.' and '..' in path.
[[nodiscard]] auto ResolveRelativePath(
std::filesystem::path const& path) noexcept -> std::filesystem::path {
auto normalized = path.lexically_normal();
return (normalized / "").parent_path(); // strip trailing slash
}
// NOLINTNEXTLINE(misc-no-recursion)
[[nodiscard]] auto LookupEntryPyPath(
GitTree const& tree,
std::filesystem::path::const_iterator it,
std::filesystem::path::const_iterator const& end) noexcept
-> GitTreeEntryPtr {
auto segment = *it;
auto entry = tree.LookupEntryByName(segment);
if (not entry) {
return nullptr;
}
if (++it != end) {
if (not entry->IsTree()) {
return nullptr;
}
return LookupEntryPyPath(*entry->Tree(), it, end);
}
return entry;
}
} // namespace
auto GitTree::Read(std::filesystem::path const& repo_path,
std::string const& tree_id) noexcept
-> std::optional<GitTree> {
auto cas = GitCAS::Open(repo_path);
if (not cas) {
return std::nullopt;
}
return Read(cas, tree_id);
}
auto GitTree::Read(gsl::not_null<GitCASPtr> const& cas,
std::string const& tree_id) noexcept
-> std::optional<GitTree> {
auto obj = cas->ReadObject(tree_id, /*is_hex_id=*/true);
if (not obj) {
return std::nullopt;
}
auto entries = ParseRawTreeObject(cas, *obj);
if (not entries) {
return std::nullopt;
}
return GitTree{cas, std::move(*entries)};
}
auto GitTree::LookupEntryByName(std::string const& name) const noexcept
-> GitTreeEntryPtr {
auto entry_it = entries_.find(name);
if (entry_it == entries_.end()) {
Logger::Log(
LogLevel::Error, "git tree does not contain entry {}", name);
return nullptr;
}
return entry_it->second;
}
auto GitTree::LookupEntryByPath(
std::filesystem::path const& path) const noexcept -> GitTreeEntryPtr {
auto resolved = ResolveRelativePath(path);
return LookupEntryPyPath(*this, resolved.begin(), resolved.end());
}
auto GitTreeEntry::Blob() const noexcept -> std::optional<std::string> {
if (not IsBlob()) {
return std::nullopt;
}
return cas_->ReadObject(raw_id_);
}
auto GitTreeEntry::Tree() const& noexcept -> std::optional<GitTree> const& {
auto ptr = tree_cached_.load();
if (not ptr) {
if (not tree_loading_.exchange(true)) {
ptr = kLoadTreeError;
std::optional<std::string> obj{};
if (IsTree() and (obj = cas_->ReadObject(raw_id_))) {
if (auto entries = ParseRawTreeObject(cas_, *obj)) {
ptr = std::make_shared<std::optional<GitTree>>(
GitTree{cas_, std::move(*entries)});
}
}
tree_cached_.store(ptr);
tree_cached_.notify_all();
}
else {
tree_cached_.wait(nullptr);
ptr = tree_cached_.load();
}
}
return *ptr;
}
auto GitTreeEntry::Size() const noexcept -> std::optional<std::size_t> {
if (auto header = cas_->ReadHeader(raw_id_)) {
return header->first;
}
return std::nullopt;
}
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