nginx-0.0.2-2004-03-03-00:14:37 import
diff --git a/src/event/ngx_event_busy_lock.c b/src/event/ngx_event_busy_lock.c
new file mode 100644
index 0000000..e040ad2
--- /dev/null
+++ b/src/event/ngx_event_busy_lock.c
@@ -0,0 +1,345 @@
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_event.h>
+
+/*
+ * TODO: eliminate mutex and use atomic_xchg():
+ * ev->next = ev; ngx_atomic_xchg(ngx_posted_events, ev->next);
+ * in ngx_event_busy_unlock() and ngx_event_busy_lock_handler()
+ */
+
+
+static int ngx_event_busy_lock_look_cachable(ngx_event_busy_lock_t *bl,
+ ngx_event_busy_lock_ctx_t *ctx);
+static void ngx_event_busy_lock_handler(ngx_event_t *ev);
+static void ngx_event_busy_lock_posted_handler(ngx_event_t *ev);
+
+
+/*
+ * NGX_OK: the busy lock is held
+ * NGX_BUSY: there are many the busy locks or many the waiting locks
+ * NGX_AGAIN: the all busy locks are held but we will wait the specified time
+ * NGX_ERROR: there was error while the mutex locking
+ */
+
+ngx_int_t ngx_event_busy_lock(ngx_event_busy_lock_t *bl,
+ ngx_event_busy_lock_ctx_t *ctx)
+{
+ ngx_int_t rc;
+
+#if (NGX_THREADS)
+ if (ngx_mutex_lock(bl->mutex) == NGX_ERROR) {
+ return NGX_ERROR;
+ }
+#endif
+
+ ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ctx->event->log, 0,
+ "event busy lock: b:%d mb:%d",
+ bl->busy, bl->max_busy);
+
+ if (bl->busy < bl->max_busy) {
+ bl->busy++;
+ rc = NGX_OK;
+
+ } else if (ctx->timer && bl->waiting < bl->max_waiting) {
+ bl->waiting++;
+ ngx_add_timer(ctx->event, ctx->timer);
+ ctx->event->event_handler = ngx_event_busy_lock_handler;
+
+ if (bl->events == NULL) {
+ bl->events = ctx;
+ } else {
+ bl->last->next = ctx;
+ }
+ bl->last = ctx;
+
+ rc = NGX_AGAIN;
+
+ } else {
+ rc = NGX_BUSY;
+ }
+
+#if (NGX_THREADS)
+ ngx_mutex_unlock(bl->mutex);
+#endif
+
+ return rc;
+}
+
+
+ngx_int_t ngx_event_busy_lock_cachable(ngx_event_busy_lock_t *bl,
+ ngx_event_busy_lock_ctx_t *ctx)
+{
+ ngx_int_t rc;
+
+#if (NGX_THREADS)
+ if (ngx_mutex_lock(bl->mutex) == NGX_ERROR) {
+ return NGX_ERROR;
+ }
+#endif
+
+ rc = ngx_event_busy_lock_look_cachable(bl, ctx);
+
+ ngx_log_debug3(NGX_LOG_DEBUG_EVENT, ctx->event->log, 0,
+ "event busy lock: %d w:%d mw:%d",
+ rc, bl->waiting, bl->max_waiting);
+
+ /*
+ * NGX_OK: no the same request, there is free slot and we locked it
+ * NGX_BUSY: no the same request and there is no free slot
+ * NGX_AGAIN: the same request is processing
+ */
+
+ if (rc == NGX_AGAIN) {
+
+ if (ctx->timer && bl->waiting < bl->max_waiting) {
+ bl->waiting++;
+ ngx_add_timer(ctx->event, ctx->timer);
+ ctx->event->event_handler = ngx_event_busy_lock_handler;
+
+ if (bl->events == NULL) {
+ bl->events = ctx;
+ } else {
+ bl->last->next = ctx;
+ }
+ bl->last = ctx;
+
+ } else {
+ rc = NGX_BUSY;
+ }
+ }
+
+#if (NGX_THREADS)
+ ngx_mutex_unlock(bl->mutex);
+#endif
+
+ return rc;
+}
+
+
+ngx_int_t ngx_event_busy_unlock(ngx_event_busy_lock_t *bl,
+ ngx_event_busy_lock_ctx_t *ctx)
+{
+ ngx_event_t *ev;
+ ngx_event_busy_lock_ctx_t *wakeup;
+
+#if (NGX_THREADS)
+ if (ngx_mutex_lock(bl->mutex) == NGX_ERROR) {
+ return NGX_ERROR;
+ }
+#endif
+
+ if (bl->events) {
+ wakeup = bl->events;
+ bl->events = bl->events->next;
+
+ } else {
+ wakeup = NULL;
+ bl->busy--;
+ }
+
+ /*
+ * MP:
+ * nocachable (bl->md5 == NULL): ngx_shared_mutex_unlock(mutex, !wakeup)
+ * cachable (bl->md5): ???
+ */
+
+ if (wakeup == NULL) {
+#if (NGX_THREADS)
+ ngx_mutex_unlock(bl->mutex);
+#endif
+ return NGX_OK;
+ }
+
+ if (ctx->md5) {
+ for (wakeup = bl->events; wakeup; wakeup = wakeup->next) {
+ if (wakeup->md5 == NULL) {
+ continue;
+ }
+
+ if (ngx_memcmp(ctx->md5, wakeup->md5, 16) != 0) {
+ continue;
+ }
+
+ wakeup->handler = ngx_event_busy_lock_posted_handler;
+ wakeup->cache_updated = 1;
+
+ ev = wakeup->event;
+
+#if (NGX_THREADS)
+ if (ngx_mutex_lock(ngx_posted_events_mutex) == NGX_ERROR) {
+ return NGX_ERROR;
+ }
+#endif
+
+ ev->next = (ngx_event_t *) ngx_posted_events;
+ ngx_posted_events = ev;
+
+#if (NGX_THREADS)
+ ngx_mutex_unlock(ngx_posted_events_mutex);
+#endif
+ }
+
+#if (NGX_THREADS)
+ ngx_mutex_unlock(bl->mutex);
+#endif
+
+ } else {
+ bl->waiting--;
+
+#if (NGX_THREADS)
+ ngx_mutex_unlock(bl->mutex);
+#endif
+
+ wakeup->handler = ngx_event_busy_lock_posted_handler;
+ wakeup->locked = 1;
+
+ ev = wakeup->event;
+
+ if (ev->timer_set) {
+ ngx_del_timer(ev);
+ }
+
+#if (NGX_THREADS)
+ if (ngx_mutex_lock(ngx_posted_events_mutex) == NGX_ERROR) {
+ return NGX_ERROR;
+ }
+#endif
+
+ ev->next = (ngx_event_t *) ngx_posted_events;
+ ngx_posted_events = ev;
+
+#if (NGX_THREADS)
+ ngx_mutex_unlock(ngx_posted_events_mutex);
+#endif
+ }
+
+ return NGX_OK;
+}
+
+
+ngx_int_t ngx_event_busy_lock_cancel(ngx_event_busy_lock_t *bl,
+ ngx_event_busy_lock_ctx_t *ctx)
+{
+ ngx_event_busy_lock_ctx_t *c, *p;
+
+#if (NGX_THREADS)
+ if (ngx_mutex_lock(bl->mutex) == NGX_ERROR) {
+ return NGX_ERROR;
+ }
+#endif
+
+ bl->waiting--;
+
+ if (ctx == bl->events) {
+ bl->events = ctx->next;
+
+ } else {
+ p = bl->events;
+ for (c = bl->events->next; c; c = c->next) {
+ if (c == ctx) {
+ p->next = ctx->next;
+ break;
+ }
+ p = c;
+ }
+ }
+
+#if (NGX_THREADS)
+ ngx_mutex_unlock(bl->mutex);
+#endif
+
+ return NGX_OK;
+}
+
+
+static int ngx_event_busy_lock_look_cachable(ngx_event_busy_lock_t *bl,
+ ngx_event_busy_lock_ctx_t *ctx)
+{
+ ngx_int_t free;
+ ngx_uint_t i, bit, cachable, mask;
+
+ bit = 0;
+ cachable = 0;
+ free = -1;
+
+#if (NGX_SUPPRESS_WARN)
+ mask = 0;
+#endif
+
+ for (i = 0; i < bl->max_busy; i++) {
+
+ if ((bit & 7) == 0) {
+ mask = bl->md5_mask[i / 8];
+ }
+
+ if (mask & 1) {
+ if (ngx_memcmp(&bl->md5[i * 16], ctx->md5, 16) == 0) {
+ return NGX_AGAIN;
+ }
+ cachable++;
+
+ } else if (free == -1) {
+ free = i;
+ }
+
+ if (cachable == bl->cachable) {
+ if (free == -1 && cachable < bl->max_busy) {
+ free = i + 1;
+ }
+
+ break;
+ }
+
+ mask >>= 1;
+ bit++;
+ }
+
+ if (free == -1) {
+ return NGX_BUSY;
+ }
+
+#if 0
+ if (bl->busy == bl->max_busy) {
+ return NGX_BUSY;
+ }
+#endif
+
+ ngx_memcpy(&bl->md5[free * 16], ctx->md5, 16);
+ bl->md5_mask[free / 8] |= 1 << (free & 7);
+ ctx->slot = free;
+
+ bl->cachable++;
+ bl->busy++;
+
+ return NGX_OK;
+}
+
+
+static void ngx_event_busy_lock_handler(ngx_event_t *ev)
+{
+ ev->event_handler = ngx_event_busy_lock_posted_handler;
+
+#if (NGX_THREADS)
+ if (ngx_mutex_lock(ngx_posted_events_mutex) == NGX_ERROR) {
+ return;
+ }
+#endif
+
+ ev->next = (ngx_event_t *) ngx_posted_events;
+ ngx_posted_events = ev;
+
+#if (NGX_THREADS)
+ ngx_mutex_unlock(ngx_posted_events_mutex);
+#endif
+}
+
+
+static void ngx_event_busy_lock_posted_handler(ngx_event_t *ev)
+{
+ ngx_event_busy_lock_ctx_t *ctx;
+
+ ctx = ev->data;
+ ctx->handler(ev);
+}
