Add http module and implement basic http server

1 files changed, 238 insertions, 0 deletions

diff --git a/src/looper_poll.cc b/src/looper_poll.cc
new file mode 100644
index 0000000..2fed7d2
--- /dev/null
+++ b/src/looper_poll.cc
@@ -0,0 +1,238 @@
+#include "logger.hh"
+#include "looper.hh"
+
+#include <algorithm>
+#include <cassert>
+#include <cerrno>
+#include <chrono>
+#include <cstdint>
+#include <cstring>
+#include <deque>
+#include <format>
+#include <functional>
+#include <limits>
+#include <memory>
+#include <poll.h>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+namespace looper {
+
+namespace {
+
+class LooperPoll : public Looper {
+ public:
+  LooperPoll() = default;
+
+  void add(int fd, uint8_t events,
+           std::function<void(uint8_t)> callback) override {
+    if (fd < 0)
+      return;
+    auto ret = entry_.emplace(fd, Entry(events));
+    if (!ret.second) {
+      assert(ret.first->second.delete_);
+      ret.first->second.delete_ = false;
+      ret.first->second.events_ = events;
+    }
+    ret.first->second.callback_ = std::move(callback);
+  }
+
+  void update(int fd, uint8_t events) override {
+    if (fd < 0)
+      return;
+    auto it = entry_.find(fd);
+    if (it == entry_.end() || it->second.delete_) {
+      assert(false);
+      return;
+    }
+    it->second.events_ = events;
+  }
+
+  void remove(int fd) override {
+    if (fd < 0)
+      return;
+    auto it = entry_.find(fd);
+    if (it == entry_.end())
+      return;
+    it->second.delete_ = true;
+  }
+
+  bool run(logger::Logger& logger) override {
+    while (!quit_) {
+      int timeout;
+      if (scheduled_.empty()) {
+        timeout = -1;
+      } else {
+        auto now = std::chrono::steady_clock::now();
+        while (true) {
+          if (now < scheduled_.front().target_) {
+            auto delay = std::chrono::duration_cast<std::chrono::milliseconds>(
+                scheduled_.front().target_ - now);
+            if (delay.count() <= std::numeric_limits<int>::max())
+              timeout = static_cast<int>(delay.count());
+            else
+              timeout = std::numeric_limits<int>::max();
+            break;
+          }
+          auto id = scheduled_.front().id_;
+          auto callback = std::move(scheduled_.front().callback_);
+          scheduled_.pop_front();
+          callback(id);
+          if (scheduled_.empty()) {
+            timeout = -1;
+            break;
+          }
+        }
+        // Scheduled callbacks might call quit().
+        if (quit_)
+          break;
+      }
+      // NOLINTNEXTLINE(misc-include-cleaner)
+      std::vector<struct pollfd> pollfd;
+      pollfd.reserve(entry_.size());
+      auto it = entry_.begin();
+      while (it != entry_.end()) {
+        if (it->second.delete_) {
+          it = entry_.erase(it);
+        } else {
+          // NOLINTNEXTLINE(misc-include-cleaner)
+          struct pollfd tmp;
+          tmp.fd = it->first;
+          tmp.events = events_looper2poll(it->second.events_);
+          pollfd.push_back(tmp);
+          ++it;
+        }
+      }
+      // NOLINTNEXTLINE(misc-include-cleaner)
+      int active = poll(pollfd.data(), pollfd.size(), timeout);
+      if (active < 0) {
+        if (errno == EINTR)
+          continue;
+        logger.err(std::format("Poll failed: {}", strerror(errno)));
+        return false;
+      }
+      for (auto it2 = pollfd.begin(); active; ++it2) {
+        if (it2->revents == 0)
+          continue;
+        --active;
+        auto events = events_poll2looper(it2->revents);
+        if (events) {
+          it = entry_.find(it2->fd);
+          if (!it->second.delete_) {
+            events &= (it->second.events_ | EVENT_ERROR);
+            if (events) {
+              it->second.callback_(events);
+            }
+          }
+        }
+      }
+    }
+    // Reset quit_ so run() can be called again
+    quit_ = false;
+    return true;
+  }
+
+  void quit() override { quit_ = true; }
+
+  uint32_t schedule(double delay,
+                    std::function<void(uint32_t)> callback) override {
+    assert(delay >= 0.0);
+    uint32_t id = next_schedule_id();
+    auto target =
+        std::chrono::steady_clock::now() +
+        std::chrono::duration_cast<std::chrono::steady_clock::duration>(
+            std::chrono::duration<double>(delay));
+    auto insert = scheduled_.end();
+    while (insert != scheduled_.begin()) {
+      auto prev = insert - 1;
+      if (prev->target_ < target)
+        break;
+      insert = prev;
+    }
+    scheduled_.emplace(insert, std::move(callback), id, target);
+    return id;
+  }
+
+  void cancel(uint32_t id) override {
+    auto it = std::ranges::find_if(scheduled_, [id](auto const& scheduled) {
+      return scheduled.id_ == id;
+    });
+    if (it != scheduled_.end()) {
+      scheduled_.erase(it);
+    } else {
+      assert(false);
+    }
+  }
+
+ private:
+  struct Entry {
+    uint8_t events_;
+    std::function<void(uint8_t)> callback_;
+    bool delete_{false};
+
+    explicit Entry(uint8_t events) : events_(events) {}
+  };
+
+  struct Scheduled {
+    std::function<void(uint32_t)> callback_;
+    uint32_t id_;
+    std::chrono::steady_clock::time_point target_;
+
+    Scheduled(std::function<void(uint32_t)> callback, uint32_t id,
+              std::chrono::steady_clock::time_point target)
+        : callback_(std::move(callback)), id_(id), target_(target) {}
+  };
+
+  static short events_looper2poll(uint8_t events) {
+    short ret = 0;
+    if (events & EVENT_READ)
+      // NOLINTNEXTLINE(misc-include-cleaner)
+      ret |= POLLIN | POLLPRI;
+    if (events & EVENT_WRITE)
+      // NOLINTNEXTLINE(misc-include-cleaner)
+      ret |= POLLOUT;
+    return ret;
+  }
+
+  static uint8_t events_poll2looper(short events) {
+    uint8_t ret = 0;
+    // NOLINTNEXTLINE(misc-include-cleaner)
+    if (events & (POLLIN | POLLPRI | POLLHUP))
+      ret |= EVENT_READ;
+    // NOLINTNEXTLINE(misc-include-cleaner)
+    if (events & POLLOUT)
+      ret |= EVENT_WRITE;
+    // NOLINTNEXTLINE(misc-include-cleaner)
+    if (events & (POLLERR | POLLNVAL))
+      ret |= EVENT_ERROR;
+    return ret;
+  }
+
+  uint32_t next_schedule_id() {
+    while (true) {
+      uint32_t ret = next_schedule_id_++;
+      if (ret) {
+        bool found = std::ranges::any_of(
+            scheduled_,
+            [ret](auto const& scheduled) { return scheduled.id_ == ret; });
+        if (!found)
+          return ret;
+      }
+    }
+  }
+
+  bool quit_{false};
+  std::unordered_map<int, Entry> entry_;
+  uint32_t next_schedule_id_{1};
+  std::deque<Scheduled> scheduled_;
+};
+
+}  // namespace
+
+[[nodiscard]]
+std::unique_ptr<Looper> create() {
+  return std::make_unique<LooperPoll>();
+}
+
+}  // namespace looper