Refactor linux backend event loops

Allow waiting for events on an arbitrary number of fds. Needed
for async DBUS integration.

glfw/backend_utils.c

@@ -0,0 +1,115 @@
+/*
+ * backend_utils.c
+ * Copyright (C) 2018 Kovid Goyal <kovid at kovidgoyal.net>
+ *
+ * Distributed under terms of the GPL3 license.
+ */
+
+#define _GNU_SOURCE
+#include "backend_utils.h"
+
+#include <string.h>
+#include <errno.h>
+
+#ifdef __NetBSD__
+#define ppoll pollts
+#endif
+
+void
+update_fds(EventLoopData *eld) {
+    eld->fds_count = 0;
+    for (nfds_t i = 0; i < eld->watches_count; i++) {
+        Watch *w = eld->watches + i;
+        if (w->enabled) {
+            eld->fds[eld->fds_count].fd = w->fd;
+            eld->fds[eld->fds_count].events = w->events;
+            eld->fds_count++;
+        }
+    }
+}
+
+void
+addWatch(EventLoopData *eld, int fd, int events, int enabled, watch_callback_func cb, void *cb_data) {
+    removeWatch(eld, fd);
+    if (eld->watches_count >= sizeof(eld->watches)/sizeof(eld->watches[0])) return;
+    Watch *w = eld->watches + eld->watches_count++;
+    w->fd = fd; w->events = events; w->enabled = enabled;
+    w->callback = cb;
+    w->callback_data = cb_data;
+    update_fds(eld);
+}
+
+void
+removeWatch(EventLoopData *eld, int fd) {
+    for (nfds_t i = 0; i < eld->watches_count; i++) {
+        if (eld->watches[i].fd == fd) {
+            eld->watches_count--;
+            if (i < eld->watches_count) {
+                memmove(eld->watches + i, eld->watches + i + 1, sizeof(eld->watches[0]) * (eld->watches_count - i));
+            }
+            update_fds(eld);
+            break;
+        }
+    }
+}
+
+void
+toggleWatch(EventLoopData *eld, int fd, int enabled) {
+    for (nfds_t i = 0; i < eld->watches_count; i++) {
+        if (eld->watches[i].fd == fd) {
+            if (eld->watches[i].enabled != enabled) {
+                eld->watches[i].enabled = enabled;
+                update_fds(eld);
+            }
+            break;
+        }
+    }
+}
+
+void
+prepareForPoll(EventLoopData *eld) {
+    for (nfds_t i = 0; i < eld->fds_count; i++) eld->fds[i].revents = 0;
+}
+
+int
+pollWithTimeout(struct pollfd *fds, nfds_t nfds, double timeout) {
+    const long seconds = (long) timeout;
+    const long nanoseconds = (long) ((timeout - seconds) * 1e9);
+    struct timespec tv = { seconds, nanoseconds };
+    return ppoll(fds, nfds, &tv, NULL);
+}
+
+void
+dispatchEvents(EventLoopData *eld) {
+    for (unsigned w = 0, f = 0; f < eld->fds_count; f++) {
+        while(eld->watches[w].fd != eld->fds[f].fd) w++;
+        Watch *ww = eld->watches + w;
+        if (eld->fds[f].revents & ww->events) {
+            ww->ready = 1;
+            if (ww->callback) ww->callback(ww->fd, eld->fds[f].revents, ww->callback_data);
+        } else ww->ready = 0;
+    }
+}
+
+static void
+drain_wakeup_fd(int fd, int events, void* data) {
+    static char drain_buf[64];
+    while(read(fd, drain_buf, sizeof(drain_buf)) < 0 && errno == EINTR);
+}
+
+void
+initPollData(EventLoopData *eld, int wakeup_fd, int display_fd) {
+    addWatch(eld, display_fd, POLLIN, 1, NULL, NULL);
+    addWatch(eld, wakeup_fd, POLLIN, 1, drain_wakeup_fd, NULL);
+}
+
+void
+closeFds(int *fds, size_t count) {
+    while(count--) {
+        if (*fds > 0) {
+            close(*fds);
+            *fds = -1;
+        }
+        fds++;
+    }
+}

glfw/backend_utils.h

@@ -25,42 +25,30 @@
 //========================================================================
 
 #pragma once
-#include <unistd.h>
 #include <poll.h>
-#include <errno.h>
+#include <unistd.h>
 
-#ifdef __NetBSD__
-#define ppoll pollts
-#endif
+typedef void(*watch_callback_func)(int, int, void*);
 
-static inline void
-drainFd(int fd) {
-    static char drain_buf[64];
-    while(read(fd, drain_buf, sizeof(drain_buf)) < 0 && errno == EINTR);
-}
+typedef struct {
+    int fd, events, enabled, ready;
+    watch_callback_func callback;
+    void *callback_data;
+} Watch;
+
+typedef struct {
+    struct pollfd fds[32];
+    int wakeupFds[2];
+    nfds_t watches_count, fds_count;
+    Watch watches[32];
+} EventLoopData;
 
 
-static inline int
-pollWithTimeout(struct pollfd *fds, nfds_t nfds, double timeout) {
-    const long seconds = (long) timeout;
-    const long nanoseconds = (long) ((timeout - seconds) * 1e9);
-    struct timespec tv = { seconds, nanoseconds };
-    return ppoll(fds, nfds, &tv, NULL);
-}
-
-static inline void
-initPollData(struct pollfd *fds, int wakeup_fd, int display_fd) {
-    fds[0].fd = wakeup_fd; fds[1].fd = display_fd;
-    fds[0].events = POLLIN; fds[1].events = POLLIN;
-}
-
-static inline void
-closeFds(int *fds, size_t count) {
-    while(count--) {
-        if (*fds > 0) {
-            close(*fds);
-            *fds = -1;
-        }
-        fds++;
-    }
-}
+void addWatch(EventLoopData *eld, int fd, int events, int enabled, watch_callback_func cb, void *cb_data);
+void removeWatch(EventLoopData *eld, int fd);
+void toggleWatch(EventLoopData *eld, int fd, int enabled);
+void prepareForPoll(EventLoopData *eld);
+int pollWithTimeout(struct pollfd *fds, nfds_t nfds, double timeout);
+void dispatchEvents(EventLoopData *eld);
+void closeFds(int *fds, size_t count);
+void initPollData(EventLoopData *eld, int wakeup_fd, int display_fd);

glfw/glfw.py

@@ -283,7 +283,6 @@ def main():
     for src in files_to_copy:
         shutil.copy2(src, '.')
     shutil.copy2(glfw_header, '.')
-    patch_in_file('internal.h', lambda x: x.replace('../include/GLFW/', ''))
     patch_in_file('cocoa_window.m', lambda x: re.sub(
         r'[(]void[)]loadMainMenu.+?}', '(void)loadMainMenu\n{ // removed by Kovid as it generated compiler warnings \n}\n', x, flags=re.DOTALL))
     json.dump(

glfw/source-info.json

@@ -84,6 +84,7 @@
       "ibus_glfw.c",
       "egl_context.c",
       "osmesa_context.c",
+      "backend_utils.c",
       "linux_joystick.c",
       "null_joystick.c"
     ]
@@ -139,6 +140,7 @@
       "glx_context.c",
       "egl_context.c",
       "osmesa_context.c",
+      "backend_utils.c",
       "linux_joystick.c",
       "null_joystick.c"
     ]

glfw/wl_init.c

@@ -664,7 +664,7 @@ int _glfwPlatformInit(void)
                         "Wayland: Failed to connect to display");
         return GLFW_FALSE;
     }
-    initPollData(_glfw.wl.eventLoopData.fds, _glfw.wl.eventLoopData.wakeupFds[0], wl_display_get_fd(_glfw.wl.display));
+    initPollData(&_glfw.wl.eventLoopData, _glfw.wl.eventLoopData.wakeupFds[0], wl_display_get_fd(_glfw.wl.display));
 
     _glfw.wl.registry = wl_display_get_registry(_glfw.wl.display);
     wl_registry_add_listener(_glfw.wl.registry, &registryListener, NULL);

glfw/wl_platform.h

@@ -49,6 +49,7 @@ typedef VkBool32 (APIENTRY *PFN_vkGetPhysicalDeviceWaylandPresentationSupportKHR
 #else
 #include "null_joystick.h"
 #endif
+#include "backend_utils.h"
 #include "xkb_glfw.h"
 #include "egl_context.h"
 #include "osmesa_context.h"
@@ -230,10 +231,7 @@ typedef struct _GLFWlibraryWayland
         PFN_wl_egl_window_resize window_resize;
     } egl;
 
-    struct {
-        struct pollfd fds[2];
-        int wakeupFds[2];
-    } eventLoopData;
+    EventLoopData eventLoopData;
 
 } _GLFWlibraryWayland;
 

glfw/wl_window.c

@@ -735,19 +735,18 @@ handleEvents(double timeout)
     dispatchPendingKeyRepeats();
     timeout = adjustTimeoutForKeyRepeat(timeout);
     GLFWbool read_ok = GLFW_FALSE;
-    for (nfds_t i = 0; i < 2; i++) _glfw.wl.eventLoopData.fds[i].revents = 0;
+    prepareForPoll(&_glfw.wl.eventLoopData);
 
     if (timeout >= 0) {
-        const int result = pollWithTimeout(_glfw.wl.eventLoopData.fds, 2, timeout);
-        if (result > 0)
-        {
-            if (_glfw.wl.eventLoopData.fds[0].revents & POLLIN) drainFd(_glfw.wl.eventLoopData.fds[0].fd);
-            read_ok = _glfw.wl.eventLoopData.fds[1].revents & POLLIN;
+        const int result = pollWithTimeout(_glfw.wl.eventLoopData.fds, _glfw.wl.eventLoopData.fds_count, timeout);
+        if (result > 0) {
+            dispatchEvents(&_glfw.wl.eventLoopData);
+            read_ok = _glfw.wl.eventLoopData.watches[0].ready;
         }
     } else {
-        if (poll(_glfw.wl.eventLoopData.fds, 2, -1) > 0) {
-            if (_glfw.wl.eventLoopData.fds[0].revents & POLLIN) drainFd(_glfw.wl.eventLoopData.fds[0].fd);
-            read_ok = _glfw.wl.eventLoopData.fds[1].revents & POLLIN;
+        if (poll(_glfw.wl.eventLoopData.fds, _glfw.wl.eventLoopData.fds_count, -1) > 0) {
+            dispatchEvents(&_glfw.wl.eventLoopData);
+            read_ok = _glfw.wl.eventLoopData.watches[0].ready;
         }
     }
     if (read_ok) {

glfw/x11_init.c

@@ -640,8 +640,7 @@ int _glfwPlatformInit(void)
         return GLFW_FALSE;
     }
 
-    initPollData(_glfw.x11.eventLoopData.fds, _glfw.x11.eventLoopData.wakeupFds[0], ConnectionNumber(_glfw.x11.display));
-    _glfw.x11.eventLoopData.fds[2].events = POLLIN;
+    initPollData(&_glfw.x11.eventLoopData, _glfw.x11.eventLoopData.wakeupFds[0], ConnectionNumber(_glfw.x11.display));
 
     _glfw.x11.screen = DefaultScreen(_glfw.x11.display);
     _glfw.x11.root = RootWindow(_glfw.x11.display, _glfw.x11.screen);
@@ -660,6 +659,8 @@ int _glfwPlatformInit(void)
 #if defined(__linux__)
     if (!_glfwInitJoysticksLinux())
         return GLFW_FALSE;
+    if (_glfw.linjs.inotify > 0)
+        addWatch(&_glfw.x11.eventLoopData, _glfw.linjs.inotify, POLLIN, 1, NULL, NULL);
 #endif
 
     _glfwInitTimerPOSIX();

glfw/x11_platform.h

@@ -53,6 +53,7 @@
 
 // The libxkb library is used for improved keyboard support
 #include "xkb_glfw.h"
+#include "backend_utils.h"
 
 typedef XRRCrtcGamma* (* PFN_XRRAllocGamma)(int);
 typedef void (* PFN_XRRFreeCrtcInfo)(XRRCrtcInfo*);
@@ -383,10 +384,7 @@ typedef struct _GLFWlibraryX11
         PFN_XRenderFindVisualFormat FindVisualFormat;
     } xrender;
 
-    struct {
-        struct pollfd fds[3];
-        int wakeupFds[2];
-    } eventLoopData;
+    EventLoopData eventLoopData;
 
 } _GLFWlibraryX11;
 

glfw/x11_window.c

@@ -56,18 +56,11 @@
 //
 static GLFWbool waitForEvent(double* timeout)
 {
-    nfds_t count = 2;
+    nfds_t count = _glfw.x11.eventLoopData.fds_count;
 
-#if defined(__linux__)
-    if (_glfw.linjs.inotify > 0)
-    {
-        count = 3;
-        _glfw.x11.eventLoopData.fds[2].fd = _glfw.linjs.inotify;
-    }
-#endif
     for (;;)
     {
-        for (nfds_t i = 0; i < count; i++) _glfw.x11.eventLoopData.fds[i].revents = 0;
+        prepareForPoll(&_glfw.x11.eventLoopData);
         if (timeout)
         {
             const uint64_t base = _glfwPlatformGetTimerValue();
@@ -75,9 +68,8 @@ static GLFWbool waitForEvent(double* timeout)
             *timeout -= (_glfwPlatformGetTimerValue() - base) /
                 (double) _glfwPlatformGetTimerFrequency();
 
-            if (result > 0)
-            {
-                if (_glfw.x11.eventLoopData.fds[0].revents & POLLIN) drainFd(_glfw.x11.eventLoopData.fds[0].fd);
+            if (result > 0) {
+                dispatchEvents(&_glfw.x11.eventLoopData);
                 return GLFW_TRUE;
             }
             if (result == 0)
@@ -87,9 +79,8 @@ static GLFWbool waitForEvent(double* timeout)
         }
         else {
             const int result = poll(_glfw.x11.eventLoopData.fds, count, -1);
-            if (result > 0)
-            {
-                if (_glfw.x11.eventLoopData.fds[0].revents & POLLIN) drainFd(_glfw.x11.eventLoopData.fds[0].fd);
+            if (result > 0) {
+                dispatchEvents(&_glfw.x11.eventLoopData);
                 return GLFW_TRUE;
             }
             if (result == 0)