packages/net/nginx-util/src/ubus-cxx.hpp
acooler15 204bc8f478 update nginx-util to 1.5-1
use UCI for server configuration
2021-02-11 10:40:03 +08:00

355 lines
9.0 KiB
C++

#ifndef _UBUS_CXX_HPP
#define _UBUS_CXX_HPP
#include <libubus.h>
#include <cassert>
#include <memory>
#include <mutex>
#include <string>
#include <utility>
#include <vector>
#ifndef NDEBUG
#include <iostream>
#endif
namespace ubus {
static constexpr int call_timeout = 500;
using msg_ptr = std::shared_ptr<const blob_attr>;
using strings = std::vector<std::string>;
inline auto concat(strings dest)
{
return dest;
}
template <class... Strings>
inline auto concat(strings dest, strings src, Strings... more)
{
dest.reserve(dest.size() + src.size());
dest.insert(std::end(dest), std::make_move_iterator(std::begin(src)),
std::make_move_iterator(std::end(src)));
return concat(std::move(dest), std::move(more)...);
}
template <class S, class... Strings>
inline auto concat(strings dest, S src, Strings... more)
{
dest.emplace_back(std::move(src));
return concat(std::move(dest), std::move(more)...);
}
class iterator {
private:
const strings& keys;
const size_t n = 0;
size_t i = 0;
const blob_attr* pos = nullptr;
std::unique_ptr<iterator> cur{};
iterator* parent = nullptr;
size_t rem = 0;
[[nodiscard]] inline auto matches() const -> bool
{
return (keys[i].empty() || blobmsg_name(cur->pos) == keys[i]);
}
explicit iterator(iterator* par)
: keys{par->keys}, n{par->n}, pos{par->pos}, cur{this}, parent{par}
{
if (pos != nullptr) {
rem = blobmsg_data_len(pos);
pos = static_cast<blob_attr*>(blobmsg_data(pos));
}
}
public:
explicit iterator(const blob_attr* msg, const strings& key_filter = {""})
: keys{key_filter}, n{keys.size() - 1}, pos{msg}, cur{this}
{
if (pos != nullptr) {
rem = blobmsg_data_len(pos);
pos = static_cast<blob_attr*>(blobmsg_data(pos));
if (rem == 0) {
pos = nullptr;
}
else if (i != n || !matches()) {
++*this;
}
}
}
inline iterator(iterator&&) noexcept = default;
inline iterator(const iterator&) = delete;
inline auto operator=(const iterator&) -> iterator& = delete;
inline auto operator=(iterator &&) -> iterator& = delete;
inline auto operator*()
{
return cur->pos;
}
inline auto operator!=(const iterator& rhs)
{
return (cur->rem != rhs.cur->rem || cur->pos != rhs.cur->pos);
}
auto operator++() -> iterator&;
inline ~iterator()
{
if (cur.get() == this) {
static_cast<void>(cur.release());
}
}
};
class message {
private:
const msg_ptr msg{}; // initialized by callback.
const strings keys{};
public:
inline explicit message(msg_ptr message_ptr, strings key_filter = {""})
: msg{std::move(message_ptr)}, keys{std::move(key_filter)}
{}
inline message(message&&) = default;
inline message(const message&) = delete;
inline auto operator=(message &&) -> message& = delete;
inline auto operator=(const message&) -> message& = delete;
[[nodiscard]] inline auto begin() const -> iterator
{
return iterator{msg.get(), keys};
}
[[nodiscard]] inline auto end() const -> iterator
{
return iterator{nullptr, keys};
}
inline explicit operator bool() const
{
return begin() != end();
}
template <class... Strings>
auto filter(Strings... key_filter)
{
strings both{};
if (keys.size() != 1 || !keys[0].empty()) {
both = keys;
}
both = concat(std::move(both), std::move(key_filter)...);
return std::move(message{msg, std::move(both)});
}
inline ~message() = default;
};
class lock_shared_resources {
private:
static std::mutex inuse;
public:
inline lock_shared_resources()
{
inuse.lock();
}
inline lock_shared_resources(lock_shared_resources&&) noexcept = default;
inline lock_shared_resources(const lock_shared_resources&) = delete;
inline auto operator=(const lock_shared_resources&) -> auto& = delete;
inline auto operator=(lock_shared_resources &&) -> auto&& = delete;
// NOLINTNEXTLINE(readability-convert-member-functions-to-static)
inline auto get_context() -> ubus_context* // is member to enforce inuse.
{
static auto ubus_freeing = [](ubus_context* ctx) { ubus_free(ctx); };
static std::unique_ptr<ubus_context, decltype(ubus_freeing)> lazy_ctx{ubus_connect(nullptr),
ubus_freeing};
if (!lazy_ctx) { // it could be available on a later call:
lazy_ctx.reset(ubus_connect(nullptr));
if (!lazy_ctx) {
throw std::runtime_error("ubus error: cannot connect context");
}
}
return lazy_ctx.get();
}
// NOLINTNEXTLINE(readability-convert-member-functions-to-static)
inline auto get_blob_buf() -> blob_buf* // is member to enforce inuse.
{
static blob_buf buf;
static auto blob_buf_freeing = [](blob_buf* b) { blob_buf_free(b); };
static std::unique_ptr<blob_buf, decltype(blob_buf_freeing)>
created_to_free_on_the_end_of_life{&buf, blob_buf_freeing};
blob_buf_init(&buf, 0);
return &buf;
}
inline ~lock_shared_resources()
{
inuse.unlock();
}
};
template <class F>
auto call(const char* path, const char* method, F set_arguments, int timeout = call_timeout)
-> message;
inline auto call(const char* path, const char* method, int timeout = call_timeout) -> message
{
return call(
path, method, [](blob_buf* /*buf*/) { return 0; }, timeout);
}
inline auto call(const char* path, int timeout = call_timeout) -> message
{
return call(path, "", timeout);
}
// ------------------------- implementation: ----------------------------------
std::mutex lock_shared_resources::inuse;
inline auto iterator::operator++() -> iterator&
{
for (;;) {
#ifndef NDEBUG
std::cout << std::string(i, '>') << " look for " << keys[i] << " at ";
std::cout << blobmsg_name(cur->pos) << std::endl;
#endif
auto id = blob_id(cur->pos);
if ((id == BLOBMSG_TYPE_TABLE || id == BLOBMSG_TYPE_ARRAY) && i < n && matches() &&
blobmsg_data_len(cur->pos) > 0)
{ // immmerge:
++i;
auto* tmp = cur.release();
struct new_iterator : public iterator // use private constructor:
{
explicit new_iterator(iterator* par) : iterator{par} {}
};
cur = std::make_unique<new_iterator>(tmp);
}
else {
while (true) {
cur->rem -= blob_pad_len(cur->pos);
cur->pos = blob_next(cur->pos);
auto len = blob_pad_len(cur->pos);
if (cur->rem > 0 && len <= cur->rem && len >= sizeof(blob_attr)) {
break;
}
// emerge:
auto* tmp = cur->parent;
if (tmp == nullptr) {
cur->pos = nullptr;
return *cur;
}
cur.reset(tmp);
--i;
}
}
if (i == n && matches()) {
return *cur;
}
}
}
template <class F>
inline auto call(const char* path, const char* method, F set_arguments, int timeout) -> message
{
auto shared = lock_shared_resources{};
auto* ctx = shared.get_context();
uint32_t id = 0;
int err = ubus_lookup_id(ctx, path, &id);
if (err == 0) { // call
ubus_request request{};
auto* buf = shared.get_blob_buf();
err = set_arguments(buf);
if (err == 0) {
err = ubus_invoke_async(ctx, id, method, buf->head, &request);
}
if (err == 0) {
msg_ptr message_ptr;
/* Cannot capture message_ptr, the lambda would be another type.
* Pass a location where to save the message as priv pointer when
* invoking and get it back here:
*/
request.priv = &message_ptr;
request.data_cb = [](ubus_request* req, int /*type*/, blob_attr* msg) {
if (req == nullptr || msg == nullptr) {
return;
}
auto* saved = static_cast<msg_ptr*>(req->priv);
if (saved == nullptr || *saved) {
return;
}
saved->reset(blob_memdup(msg), free);
if (!*saved) {
throw std::bad_alloc();
}
};
err = ubus_complete_request(ctx, &request, timeout);
if (err == 0) {
return message{message_ptr};
}
}
}
std::string errmsg = "ubus::call error: cannot invoke";
errmsg += " (" + std::to_string(err) + ") " + path + " " + method;
throw std::runtime_error(errmsg);
}
} // namespace ubus
#endif