initial: Yet Another Surface Library (YASL) 0.1.0

A minimal, modern desktop window surface library in C.
Supports Wayland on Linux and Cocoa/Metal on macOS with
presentation timing, fractional scaling, IME, and CSD.

1 files changed, 124 insertions, 0 deletions

diff --git a/src/common/loop.c b/src/common/loop.c
new file mode 100644
index 0000000..4c2da0d
--- /dev/null
+++ b/src/common/loop.c
@@ -0,0 +1,124 @@
+#define _POSIX_C_SOURCE 200809L
+#include "yasl/yasl.h"
+
+#include <errno.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+#define YASL_MAX_FDS 64
+
+typedef int (*yasl_loop_fd_fn)(int fd, short revents, void *ud);
+
+struct yasl_fd_source {
+    yasl_loop_fd_fn fn;
+    void *ud;
+    int id;
+    int fd;
+    short events;
+};
+
+struct yasl_loop {
+    struct yasl_fd_source fds[YASL_MAX_FDS];
+    struct pollfd pollfds[YASL_MAX_FDS];
+    int count;
+    int next_id;
+    bool running;
+};
+
+uint64_t yasl_loop_now_ns(void)
+{
+    struct timespec ts;
+    clock_gettime(CLOCK_MONOTONIC, &ts);
+    return (uint64_t)ts.tv_sec * 1000000000ull + (uint64_t)ts.tv_nsec;
+}
+
+struct yasl_loop *yasl_loop_create(void)
+{
+    struct yasl_loop *l = calloc(1, sizeof(*l));
+    if (!l) return NULL;
+    l->next_id = 1;
+    return l;
+}
+
+void yasl_loop_destroy(struct yasl_loop *l)
+{
+    free(l);
+}
+
+int yasl_loop_add_fd(struct yasl_loop *l, int fd, short events,
+                     int (*fn)(int fd, short revents, void *ud), void *ud)
+{
+    if (!l || l->count >= YASL_MAX_FDS || fd < 0)
+        return -1;
+    int id = l->next_id++;
+    l->fds[l->count] = (struct yasl_fd_source){
+        .fn = fn, .ud = ud, .id = id, .fd = fd, .events = events,
+    };
+    l->pollfds[l->count] = (struct pollfd){
+        .fd = fd, .events = events, .revents = 0,
+    };
+    l->count++;
+    return id;
+}
+
+int yasl_loop_del_fd(struct yasl_loop *l, int id)
+{
+    if (!l || id <= 0) return -1;
+    for (int i = 0; i < l->count; i++) {
+        if (l->fds[i].id == id) {
+            l->count--;
+            l->fds[i] = l->fds[l->count];
+            l->pollfds[i] = l->pollfds[l->count];
+            return 0;
+        }
+    }
+    return -1;
+}
+
+int yasl_loop_set_fd_events(struct yasl_loop *l, int id, short events)
+{
+    if (!l || id <= 0) return -1;
+    for (int i = 0; i < l->count; i++) {
+        if (l->fds[i].id == id) {
+            l->fds[i].events = events;
+            l->pollfds[i].events = events;
+            return 0;
+        }
+    }
+    return -1;
+}
+
+void yasl_loop_kick(struct yasl_loop *l)
+{
+    (void)l;
+}
+
+int yasl_loop_run(struct yasl_loop *l)
+{
+    if (!l) return -1;
+    l->running = true;
+    while (l->running) {
+        int n = poll(l->pollfds, (nfds_t)l->count, -1);
+        if (n < 0) {
+            if (errno == EINTR) continue;
+            return -1;
+        }
+        for (int i = 0; i < l->count && l->running; i++) {
+            if (l->pollfds[i].revents) {
+                struct yasl_fd_source src = l->fds[i];
+                short revents = l->pollfds[i].revents;
+                l->pollfds[i].revents = 0;
+                if (src.fn)
+                    src.fn(src.fd, revents, src.ud);
+            }
+        }
+    }
+    return 0;
+}
+
+void yasl_loop_quit(struct yasl_loop *l)
+{
+    if (l) l->running = false;
+}