Merge pull request #128 from linuxdoesitbetter/main

Created a new subdirectory for the development of an event loop and a…

final/eventloop/CMakeLists.txt

@@ -0,0 +1,27 @@
+cmake_minimum_required(VERSION 3.18)
+
+project(eventloop)
+
+add_executable(
+    eventloop
+    monitor.h
+    monitor.cpp
+    timer_monitor.h
+    timer_monitor.cpp
+    signal_monitor.h
+    signal_monitor.cpp
+    io_monitor.h
+    io_monitor.cpp
+    eventloop.h
+    eventloop.cpp
+    main.cpp )
+
+#target_compile_options(eventloop PUBLIC -std=c++14 -Wall -Wextra -Wpedantic -Werror )
+target_compile_options(eventloop PUBLIC -std=c++14 -Wall -Wextra -Weffc++ -pedantic -pedantic-errors -Wformat-nonliteral -Wformat-security -Wformat-y2k -Wimport -Winit-self -Winvalid-pch -Wlong-long -Wmissing-braces -Wmissing-field-initializers -Wmissing-format-attribute -Wmissing-include-dirs -Wmissing-noreturn -Wpacked -Wparentheses -Wpointer-arith -Wredundant-decls -Wreturn-type -Wsequence-point -Wshadow -Wsign-compare -fstack-protector -Wstrict-aliasing -Wstrict-aliasing=3 -Wswitch -Wtrigraphs -Wuninitialized -Wunknown-pragmas -Wunreachable-code -Wunused -Wunused-function -Wunused-label -Wunused-parameter -Wunused-value -Wunused-variable -Wvariadic-macros -Wvolatile-register-var -Wwrite-strings -Wsign-promo -Woverloaded-virtual -Wstrict-null-sentinel -fext-numeric-literals -Wreorder -Wnoexcept -Wnarrowing -Wliteral-suffix -Wctor-dtor-privacy -ftree-loop-distribute-patterns -Wmemset-transposed-args -Wno-format-nonliteral )
+
+target_link_libraries(
+    eventloop
+    rt
+    c )
+
+install(TARGETS eventloop RUNTIME DESTINATION bin)

final/eventloop/eventloop-class-diagram.txt

@@ -0,0 +1,16 @@
+
+
+ ┌───────────┐
+ │ EventLoop │
+ └─────┬─────┘
+       : 1           ┌───────────────┐
+       :         ┌───┤ SignalMonitor │
+       : *       │   └───────────────┘
+  ┌────┴────┐    │   ┌──────────────┐
+  │ Monitor │◄───┼───┤ TimerMonitor │
+  └─────────┘    │   └──────────────┘
+                 │   ┌───────────┐
+                 └───┤ IoMonitor │
+                     └───────────┘
+
+

final/eventloop/eventloop.cpp

@@ -0,0 +1,116 @@
+/***********************************************************************
+* eventloop.cpp - Implements the event loop                            *
+*                                                                      *
+* This file is part of the FINAL CUT widget toolkit                    *
+*                                                                      *
+* Copyright 2023 Andreas Noe                                           *
+*                                                                      *
+* FINAL CUT is free software; you can redistribute it and/or modify    *
+* it under the terms of the GNU Lesser General Public License as       *
+* published by the Free Software Foundation; either version 3 of       *
+* the License, or (at your option) any later version.                  *
+*                                                                      *
+* FINAL CUT is distributed in the hope that it will be useful, but     *
+* WITHOUT ANY WARRANTY; without even the implied warranty of           *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
+* GNU Lesser General Public License for more details.                  *
+*                                                                      *
+* You should have received a copy of the GNU Lesser General Public     *
+* License along with this program.  If not, see                        *
+* <http://www.gnu.org/licenses/>.                                      *
+***********************************************************************/
+
+#include <unistd.h>
+
+#include <iostream>
+
+#include "eventloop.h"
+
+// public methods of EventLoop
+//----------------------------------------------------------------------
+auto EventLoop::run() -> int
+{
+  running = true;
+
+  while ( running )
+  {
+    nfds_t fd_count = 0;
+    monitors_changed = false;
+
+    for (Monitor* monitor : monitors)
+    {
+      if ( monitor->isActive() )
+      {
+        fds[fd_count] = { monitor->getFd(), monitor->getEvents(), 0 };
+        lookup_table[fd_count] = monitor;
+        fd_count++;
+      }
+
+      if ( fd_count >= MAX_MONITORS )
+        break;
+    }
+
+    int poll_result{};
+
+    while ( true )
+    {
+      poll_result = poll(fds, fd_count, -1);
+
+      if ( poll_result != -1 || errno != EINTR )
+        break;
+    }
+
+    if ( poll_result == -1 )
+    {
+      std::cerr << "Arghh! " << errno << std::endl;
+      continue;
+    }
+
+    if ( poll_result <= 0 )
+      continue;
+
+    nfds_t processed_fds{0};
+
+    for (nfds_t index{0}; index < fd_count; index++)
+    {
+      pollfd& current_fd = fds[index];
+
+      if ( current_fd.revents != 0
+        && (current_fd.revents & current_fd.events) )
+      {
+        lookup_table[index]->trigger(current_fd.revents);
+
+        if ( monitors_changed
+          || int(++processed_fds) == poll_result
+          || ! running )
+        {
+          break;
+        }
+      }
+    }
+  }
+
+  return 0;
+}
+
+//----------------------------------------------------------------------
+void EventLoop::leave()
+{
+  running = false;
+}
+
+
+// private methods of EventLoop
+//----------------------------------------------------------------------
+void EventLoop::addMonitor (Monitor* monitor)
+{
+  monitors.push_back(monitor);
+  monitors_changed = true;
+}
+
+//----------------------------------------------------------------------
+void EventLoop::removeMonitor (Monitor* monitor)
+{
+  monitors.remove(monitor);
+  monitors_changed = true;
+}

final/eventloop/eventloop.h

@@ -0,0 +1,68 @@
+/***********************************************************************
+* eventloop.h - Implements the event loop                              *
+*                                                                      *
+* This file is part of the FINAL CUT widget toolkit                    *
+*                                                                      *
+* Copyright 2023 Andreas Noe                                           *
+*                                                                      *
+* FINAL CUT is free software; you can redistribute it and/or modify    *
+* it under the terms of the GNU Lesser General Public License as       *
+* published by the Free Software Foundation; either version 3 of       *
+* the License, or (at your option) any later version.                  *
+*                                                                      *
+* FINAL CUT is distributed in the hope that it will be useful, but     *
+* WITHOUT ANY WARRANTY; without even the implied warranty of           *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
+* GNU Lesser General Public License for more details.                  *
+*                                                                      *
+* You should have received a copy of the GNU Lesser General Public     *
+* License along with this program.  If not, see                        *
+* <http://www.gnu.org/licenses/>.                                      *
+***********************************************************************/
+
+/*  Standalone class
+ *  ════════════════
+ *
+ * ▕▔▔▔▔▔▔▔▔▔▔▔▏
+ * ▕ EventLoop ▏
+ * ▕▁▁▁▁▁▁▁▁▁▁▁▏
+ */
+
+#ifndef EVENTLOOP_H
+#define EVENTLOOP_H
+
+#include <list>
+#include <poll.h>
+
+#include "monitor.h"
+
+class EventLoop
+{
+  public:
+    // Constructor
+    EventLoop() = default;
+
+    // Methods
+    auto run() -> int;
+    void leave();
+
+  private:
+    // Constants
+    static constexpr nfds_t MAX_MONITORS{50};
+
+    // Methods
+    void addMonitor (Monitor*);
+    void removeMonitor (Monitor*);
+
+    // Data members
+    bool                running{false};
+    bool                monitors_changed{false};
+    std::list<Monitor*> monitors{};
+    struct pollfd       fds[MAX_MONITORS]{};
+    Monitor*            lookup_table[MAX_MONITORS]{};
+
+    // Friend classes
+    friend class Monitor;
+};
+
+#endif  // EVENTLOOP_H

final/eventloop/io_monitor.cpp

@@ -0,0 +1,46 @@
+/***********************************************************************
+* io_monitor.cpp - I/O monitoring object                               *
+*                                                                      *
+* This file is part of the FINAL CUT widget toolkit                    *
+*                                                                      *
+* Copyright 2023 Andreas Noe                                           *
+*                                                                      *
+* FINAL CUT is free software; you can redistribute it and/or modify    *
+* it under the terms of the GNU Lesser General Public License as       *
+* published by the Free Software Foundation; either version 3 of       *
+* the License, or (at your option) any later version.                  *
+*                                                                      *
+* FINAL CUT is distributed in the hope that it will be useful, but     *
+* WITHOUT ANY WARRANTY; without even the implied warranty of           *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
+* GNU Lesser General Public License for more details.                  *
+*                                                                      *
+* You should have received a copy of the GNU Lesser General Public     *
+* License along with this program.  If not, see                        *
+* <http://www.gnu.org/licenses/>.                                      *
+***********************************************************************/
+
+#include <utility>
+
+#include "io_monitor.h"
+
+// constructors and destructor
+//----------------------------------------------------------------------
+IoMonitor::IoMonitor (EventLoop* eloop)
+  : Monitor(eloop)
+{ }
+
+//----------------------------------------------------------------------
+IoMonitor::~IoMonitor() noexcept = default;  // destructor
+
+
+// public methods of IoMonitor
+//----------------------------------------------------------------------
+void IoMonitor::init ( int file_descriptor, short ev
+                     , handler_t hdl, void* uc )
+{
+  fd           = file_descriptor;
+  events       = ev;
+  handler      = std::move(hdl);
+  user_context = uc;
+}

final/eventloop/io_monitor.h

@@ -0,0 +1,53 @@
+/***********************************************************************
+* io_monitor.h - I/O monitoring object                                 *
+*                                                                      *
+* This file is part of the FINAL CUT widget toolkit                    *
+*                                                                      *
+* Copyright 2023 Andreas Noe                                           *
+*                                                                      *
+* FINAL CUT is free software; you can redistribute it and/or modify    *
+* it under the terms of the GNU Lesser General Public License as       *
+* published by the Free Software Foundation; either version 3 of       *
+* the License, or (at your option) any later version.                  *
+*                                                                      *
+* FINAL CUT is distributed in the hope that it will be useful, but     *
+* WITHOUT ANY WARRANTY; without even the implied warranty of           *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
+* GNU Lesser General Public License for more details.                  *
+*                                                                      *
+* You should have received a copy of the GNU Lesser General Public     *
+* License along with this program.  If not, see                        *
+* <http://www.gnu.org/licenses/>.                                      *
+***********************************************************************/
+
+/*  Inheritance diagram
+ *  ═══════════════════
+ *
+ *      ▕▔▔▔▔▔▔▔▔▔▏
+ *      ▕ Monitor ▏
+ *      ▕▁▁▁▁▁▁▁▁▁▏
+ *           ▲
+ *           │
+ *     ▕▔▔▔▔▔▔▔▔▔▔▔▏
+ *     ▕ IoMonitor ▏
+ *     ▕▁▁▁▁▁▁▁▁▁▁▁▏
+ */
+
+#ifndef IO_MONITOR_H
+#define IO_MONITOR_H
+
+#include "monitor.h"
+
+class IoMonitor final : public Monitor
+{
+  public:
+    // Constructor
+    IoMonitor() = delete;
+    explicit IoMonitor (EventLoop*);
+    ~IoMonitor() noexcept override;
+
+    // Method
+    void init (int, short, handler_t, void*);
+};
+
+#endif // IO_MONITOR_H