Add unix event loop.

9 files changed, 192 insertions, 51 deletions

diff --git a/include/cru/base/Base.h b/include/cru/base/Base.h
index fd409360..f8f8c8c0 100644
--- a/include/cru/base/Base.h
+++ b/include/cru/base/Base.h
@@ -93,6 +93,7 @@ struct CRU_BASE_API Interface {
 };
 
 [[noreturn]] void CRU_BASE_API UnreachableCode();
+[[noreturn]] void CRU_BASE_API NotImplemented();
 
 using Index = std::ptrdiff_t;
 
diff --git a/include/cru/base/platform/unix/EventLoop.h b/include/cru/base/platform/unix/EventLoop.h
new file mode 100644
index 00000000..bc2bcbf8
--- /dev/null
+++ b/include/cru/base/platform/unix/EventLoop.h
@@ -0,0 +1,95 @@
+#pragma once
+
+#include <optional>
+#if !defined(__unix) && !defined(__APPLE__)
+#error "This file can only be included on unix."
+#endif
+
+#include "../../Base.h"
+#include "../../Exception.h"
+#include "UnixFile.h"
+
+#include <unistd.h>
+#include <chrono>
+#include <thread>
+
+namespace cru::platform::unix {
+class UnixTimerFile : public Object2 {
+ public:
+  template <class Rep, class Period>
+  explicit UnixTimerFile(std::chrono::duration<Rep, Period> time) {
+    auto fds = OpenUniDirectionalPipe();
+    this->read_fd_ = std::move(fds.read);
+    this->write_fd_ = std::move(fds.write);
+
+    this->thread_ = std::thread([this, time] {
+      std::this_thread::sleep_for(time);
+      constexpr auto buffer = "";
+      auto written = ::write(this->write_fd_, buffer, 1);
+      if (written != 1) {
+        throw Exception(
+            "Failed to write to pipe in UnixTimerFile thread at timeout.");
+      }
+    });
+    this->thread_.detach();
+  }
+
+  int GetReadFd() const;
+
+ private:
+  UnixFileDescriptor write_fd_;
+  UnixFileDescriptor read_fd_;
+  std::thread thread_;
+};
+
+class UnixEventLoop : public Object2 {
+ public:
+  UnixEventLoop();
+
+  int Run();
+  void RequestQuit(int exit_code = 0);
+
+  int SetTimer(std::function<void()> action, std::chrono::milliseconds timeout,
+               bool repeat);
+
+  int SetImmediate(std::function<void()> action) {
+    return this->SetTimer(std::move(action), std::chrono::milliseconds::zero(),
+                          false);
+  }
+
+  int SetTimeout(std::function<void()> action,
+                 std::chrono::milliseconds timeout) {
+    return this->SetTimer(std::move(action), std::move(timeout), false);
+  }
+
+  int SetInterval(std::function<void()> action,
+                  std::chrono::milliseconds interval) {
+    return this->SetTimer(std::move(action), std::move(interval), true);
+  }
+
+ private:
+  struct TimerData {
+    int id;
+    std::chrono::milliseconds original_timeout;
+    std::chrono::milliseconds timeout;
+    bool repeat;
+    std::function<void()> action;
+
+    TimerData(int id, std::chrono::milliseconds timeout, bool repeat,
+              std::function<void()> action)
+        : id(id),
+          original_timeout(timeout),
+          timeout(timeout),
+          repeat(repeat),
+          action(std::move(action)) {}
+  };
+
+  std::thread::id running_thread_;
+
+  std::atomic_int timer_tag_;
+  std::vector<TimerData> timers_;
+
+  std::optional<int> exit_code_;
+};
+
+}  // namespace cru::platform::unix
diff --git a/include/cru/base/platform/unix/Timer.h b/include/cru/base/platform/unix/Timer.h
deleted file mode 100644
index 17abd1cc..00000000
--- a/include/cru/base/platform/unix/Timer.h
+++ /dev/null
@@ -1,43 +0,0 @@
-#pragma once
-
-#if !defined(__unix) && !defined(__APPLE__)
-#error "This file can only be included on unix."
-#endif
-
-#include "../../Base.h"
-#include "../../Exception.h"
-#include "UnixFile.h"
-
-#include <chrono>
-#include <thread>
-#include <unistd.h>
-
-namespace cru::platform::unix {
-class UnixTimerFile : public Object2 {
- public:
-  template <class Rep, class Period>
-  explicit UnixTimerFile(std::chrono::duration<Rep, Period> time) {
-    auto fds = OpenUniDirectionalPipe();
-    this->read_fd_ = std::move(fds.read);
-    this->write_fd_ = std::move(fds.write);
-
-    this->thread_ = std::thread([this, time] {
-      std::this_thread::sleep_for(time);
-      constexpr auto buffer = "";
-      auto written = ::write(this->write_fd_, buffer, 1);
-      if (written != 1) {
-        throw Exception(
-            "Failed to write to pipe in UnixTimerFile thread at timeout.");
-      }
-    });
-    this->thread_.detach();
-  }
-
-  int GetReadFd() const;
-
- private:
-  UnixFileDescriptor write_fd_;
-  UnixFileDescriptor read_fd_;
-  std::thread thread_;
-};
-}  // namespace cru::platform::unix
diff --git a/src/base/Base.cpp b/src/base/Base.cpp
index 1704f8a9..c6d9ac07 100644
--- a/src/base/Base.cpp
+++ b/src/base/Base.cpp
@@ -4,4 +4,5 @@
 
 namespace cru {
 void UnreachableCode() { std::terminate(); }
+void NotImplemented() { std::terminate(); }
 }  // namespace cru
diff --git a/src/base/CMakeLists.txt b/src/base/CMakeLists.txt
index 300898af..7e7b0127 100644
--- a/src/base/CMakeLists.txt
+++ b/src/base/CMakeLists.txt
@@ -24,8 +24,8 @@ target_compile_definitions(CruBase PUBLIC $<$<CONFIG:Debug>:CRU_DEBUG>)
 
 if (UNIX AND NOT EMSCRIPTEN)
 	target_sources(CruBase PRIVATE
+		platform/unix/EventLoop.cpp
 		platform/unix/PosixSpawnSubProcess.cpp
-		platform/unix/Timer.cpp
 		platform/unix/UnixFile.cpp
 		platform/unix/UnixFileStream.cpp
 	)
diff --git a/src/base/platform/unix/EventLoop.cpp b/src/base/platform/unix/EventLoop.cpp
new file mode 100644
index 00000000..337d8a44
--- /dev/null
+++ b/src/base/platform/unix/EventLoop.cpp
@@ -0,0 +1,92 @@
+#include "cru/base/platform/unix/EventLoop.h"
+#include "cru/base/Exception.h"
+
+#include <poll.h>
+#include <algorithm>
+#include <chrono>
+#include <thread>
+
+namespace cru::platform::unix {
+int UnixTimerFile::GetReadFd() const { return this->read_fd_; }
+
+UnixEventLoop::UnixEventLoop() : timer_tag_(1) {}
+
+int UnixEventLoop::Run() {
+  running_thread_ = std::this_thread::get_id();
+
+  pollfd poll_fds[1];
+
+  while (!exit_code_) {
+    int poll_timeout = -1;
+
+    auto iter = std::ranges::find_if(timers_, [](const TimerData &timer) {
+      return timer.timeout <= std::chrono::milliseconds::zero();
+    });
+    if (iter != timers_.end()) {
+      auto &timer = *iter;
+      if (timer.repeat) {
+        while (timer.timeout <= std::chrono::milliseconds::zero()) {
+          timer.timeout += timer.original_timeout;
+          timer.action();
+        }
+      } else {
+        auto action = timer.action;
+        timers_.erase(iter);
+        action();
+      }
+      continue;
+    }
+
+    if (!timers_.empty()) {
+      poll_timeout =
+          std::ranges::min_element(timers_, [](const TimerData &left,
+                                               const TimerData &right) {
+            return left.timeout < right.timeout;
+          })->timeout.count();
+    }
+
+    auto start = std::chrono::steady_clock::now();
+
+    ::poll(poll_fds, sizeof poll_fds / sizeof *poll_fds, poll_timeout);
+
+    // TODO: A Big Implement to handle X events.
+
+    auto end = std::chrono::steady_clock::now();
+    auto time =
+        std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
+
+    for (auto &timer : timers_) {
+      timer.timeout -= time;
+    }
+  }
+
+  return exit_code_.value();
+}
+
+void UnixEventLoop::RequestQuit(int exit_code) {}
+
+int UnixEventLoop::SetTimer(std::function<void()> action,
+                            std::chrono::milliseconds timeout, bool repeat) {
+  if (repeat) {
+    if (timeout <= std::chrono::milliseconds::zero()) {
+      throw Exception("Interval must be bigger than 0.");
+    }
+  } else {
+    if (timeout < std::chrono::milliseconds::zero()) {
+      throw Exception("Timeout must be at least 0.");
+    }
+  }
+
+  auto tag = timer_tag_++;
+
+  if (std::this_thread::get_id() == running_thread_) {
+    timers_.push_back(
+        TimerData(tag, std::move(timeout), repeat, std::move(action)));
+  } else {
+    // TODO: Implement
+  }
+
+  return tag;
+}
+
+}  // namespace cru::platform::unix
diff --git a/src/base/platform/unix/Timer.cpp b/src/base/platform/unix/Timer.cpp
deleted file mode 100644
index 25264dc8..00000000
--- a/src/base/platform/unix/Timer.cpp
+++ /dev/null
@@ -1,5 +0,0 @@
-#include "cru/base/platform/unix/Timer.h"
-
-namespace cru::platform::unix {
-int UnixTimerFile::GetReadFd() const { return this->read_fd_; }
-}  // namespace cru::platform::unix
diff --git a/test/base/CMakeLists.txt b/test/base/CMakeLists.txt
index 5abba240..95313ccb 100644
--- a/test/base/CMakeLists.txt
+++ b/test/base/CMakeLists.txt
@@ -25,7 +25,7 @@ target_compile_definitions(CruBaseTest PRIVATE
 
 if (UNIX AND NOT EMSCRIPTEN)
 	target_sources(CruBaseTest PRIVATE
-		platform/unix/TimerTest.cpp
+		platform/unix/EventLoopTest.cpp
 		platform/unix/UnixFileTest.cpp
 		platform/unix/UnixFileStreamTest.cpp
 	)
diff --git a/test/base/platform/unix/TimerTest.cpp b/test/base/platform/unix/EventLoopTest.cpp
index dc3cc1ba..f5936b2a 100644
--- a/test/base/platform/unix/TimerTest.cpp
+++ b/test/base/platform/unix/EventLoopTest.cpp
@@ -1,4 +1,4 @@
-#include "cru/base/platform/unix/Timer.h"
+#include "cru/base/platform/unix/EventLoop.h"
 
 #include <catch2/catch_test_macros.hpp>