CachedUnit lookupUnitNonRepoAuth(StringData* requestedPath,
const struct stat& statInfo) {
if (strstr(requestedPath->data(), "://") != nullptr) {
// URL-based units are not currently cached in memory, but the Repo still
// caches them on disk.
return createUnitFromUrl(requestedPath);
}
// The string we're using as a key must be static, because we're using it as
// a key in the cache (across requests).
auto const path =
makeStaticString(
// XXX: it seems weird we have to do this even though we already ran
// resolveVmInclude.
(requestedPath->data()[0] == '/'
? requestedPath
: String(SourceRootInfo::GetCurrentSourceRoot()) + StrNR(requestedPath)
).get()
);
NonRepoUnitCache::accessor acc;
if (!s_nonRepoUnitCache.insert(acc, path)) {
if (!isChanged(acc->second, statInfo)) {
return acc->second.cachedUnit;
}
}
/*
* NB: the new-unit creation path is here, and is done while holding the tbb
* lock on s_nonRepoUnitCache. This was originally done deliberately to
* avoid wasting time in the compiler (during server startup, many requests
* hit the same code initial paths that are shared, and would all be
* compiling the same files). It's not 100% clear if this is the best way to
* handle that idea, though (tbb locks spin aggressively and are expected to
* be low contention).
*/
/*
* Don't cache if createNewUnit returns an empty CachedUnit---we'll need to
* try again anyway if someone tries to load this path, since it might exist
* later.
*
* If there was a unit for this path already, we need to put it on the
* Treadmill for eventual reclaimation. We can't delete it immediately
* because other requests may still be using it.
*/
auto const cu = createUnitFromFile(path);
if (auto const oldUnit = acc->second.cachedUnit.unit) {
Treadmill::enqueue([oldUnit] { reclaimUnit(oldUnit); });
}
acc->second.cachedUnit = cu;
acc->second.mtime = statInfo.st_mtim;
acc->second.ino = statInfo.st_ino;
acc->second.devId = statInfo.st_dev;
return cu;
}
CachedUnit loadUnitNonRepoAuth(StringData* requestedPath,
const struct stat* statInfo,
OptLog& ent,
const Native::FuncTable& nativeFuncs,
const RepoOptions& options,
FileLoadFlags& flags) {
LogTimer loadTime("load_ms", ent);
if (strstr(requestedPath->data(), "://") != nullptr) {
// URL-based units are not currently cached in memory, but the Repo still
// caches them on disk.
return createUnitFromUrl(requestedPath, nativeFuncs, flags);
}
rqtrace::EventGuard trace{"WRITE_UNIT"};
// The string we're using as a key must be static, because we're using it as
// a key in the cache (across requests).
auto const path =
makeStaticString(
// XXX: it seems weird we have to do this even though we already ran
// resolveVmInclude.
(FileUtil::isAbsolutePath(requestedPath->toCppString())
? String{requestedPath}
: String(SourceRootInfo::GetCurrentSourceRoot()) + StrNR(requestedPath)
).get()
);
auto const rpath = [&] () -> const StringData* {
if (RuntimeOption::CheckSymLink) {
std::string rp = StatCache::realpath(path->data());
if (rp.size() != 0) {
if (rp.size() != path->size() ||
memcmp(rp.data(), path->data(), rp.size())) {
return makeStaticString(rp);
}
}
}
return path;
}();
Stream::Wrapper* w = nullptr;
auto& cache = getNonRepoCache(rpath, w);
assertx(
!w || &cache != &s_nonRepoUnitCache ||
!RuntimeOption::EvalUnixServerQuarantineUnits
);
// Freeing a unit while holding the tbb lock would cause a rank violation when
// recycle-tc is enabled as reclaiming dead functions requires that the code
// and metadata locks be acquired.
Unit* releaseUnit = nullptr;
SCOPE_EXIT { if (releaseUnit) delete releaseUnit; };
auto const updateAndUnlock = [] (auto& cachedUnit, auto p) {
auto old = cachedUnit.update_and_unlock(std::move(p));
if (old) {
// We don't need to do anything explicitly; the copy_ptr
// destructor will take care of it.
Treadmill::enqueue([unit_to_delete = std::move(old)] () {});
}
};
auto cuptr = [&] {
NonRepoUnitCache::const_accessor rpathAcc;
cache.insert(rpathAcc, rpath);
auto& cachedUnit = rpathAcc->second.cachedUnit;
if (auto const tmp = cachedUnit.copy()) {
if (!isChanged(tmp, statInfo, options)) {
flags = FileLoadFlags::kHitMem;
if (ent) ent->setStr("type", "cache_hit_readlock");
return tmp;
}
}
cachedUnit.lock_for_update();
try {
if (auto const tmp = cachedUnit.copy()) {
if (!isChanged(tmp, statInfo, options)) {
cachedUnit.unlock();
flags = FileLoadFlags::kWaited;
if (ent) ent->setStr("type", "cache_hit_writelock");
return tmp;
}
if (ent) ent->setStr("type", "cache_stale");
} else {
if (ent) ent->setStr("type", "cache_miss");
}
trace.finish();
auto const cu = createUnitFromFile(rpath, &releaseUnit, w, ent,
nativeFuncs, options, flags);
auto const isICE = cu.unit && cu.unit->isICE();
auto p = copy_ptr<CachedUnitWithFree>(cu, statInfo, isICE, options);
// Don't cache the unit if it was created in response to an internal error
// in ExternCompiler. Such units represent transient events.
if (UNLIKELY(isICE)) {
cachedUnit.unlock();
return p;
}
updateAndUnlock(cachedUnit, p);
return p;
} catch (...) {
cachedUnit.unlock();
throw;
}
}();
auto const ret = cuptr->cu;
if (!ret.unit || !ret.unit->isICE()) {
if (path != rpath) {
NonRepoUnitCache::const_accessor pathAcc;
cache.insert(pathAcc, path);
if (pathAcc->second.cachedUnit.get().get() != cuptr) {
auto& cachedUnit = pathAcc->second.cachedUnit;
cachedUnit.lock_for_update();
updateAndUnlock(cachedUnit, std::move(cuptr));
}
}
}
return ret;
}