Factor out reusable include for libevent

1 files changed, 95 insertions, 0 deletions

diff --git a/extra/hiredis/libevent.h b/extra/hiredis/libevent.h
new file mode 100644
index 0000000..c9bf4f1
--- /dev/null
+++ b/extra/hiredis/libevent.h
@@ -0,0 +1,95 @@
+#include <event.h>
+#include <hiredis.h>
+
+/* Prototype for the error callback. */
+typedef void (redisErrorCallback)(redisContext*);
+
+/* This struct enables us to pass both the events and the
+ * redisContext to the read and write handlers. */
+typedef struct redisEvents {
+    redisContext *context;
+    redisErrorCallback *err;
+    struct event rev, wev;
+} redisEvents;
+
+void redisLibEventRead(int fd, short event, void *arg) {
+    ((void)fd); ((void)event);
+    redisEvents *e = arg;
+
+    /* Always re-schedule read events */
+    event_add(&e->rev,NULL);
+
+    if (redisBufferRead(e->context) == REDIS_ERR) {
+        /* Handle error. */
+        e->err(e->context);
+    } else {
+        /* If processing the replies/callbacks results in an error,
+         * invoke the error callback and abort. */
+        if (redisProcessCallbacks(e->context) == REDIS_ERR) {
+            e->err(e->context);
+        }
+    }
+}
+
+void redisLibEventWrite(int fd, short event, void *arg) {
+    ((void)fd); ((void)event);
+    redisEvents *e = arg;
+    int done = 0;
+
+    if (redisBufferWrite(e->context, &done) == REDIS_ERR) {
+        /* Handle error */
+        e->err(e->context);
+    } else {
+        /* Schedule write event again when writing is not done. */
+        if (!done) {
+            event_add(&e->wev,NULL);
+        } else {
+            event_add(&e->rev,NULL);
+        }
+    }
+}
+
+/* Schedule to be notified on a write event, so the outgoing buffer
+ * can be flushed to the socket. */
+void redisLibEventOnWrite(redisContext *c, void *privdata) {
+    ((void)c);
+    redisEvents *e = privdata;
+    event_add(&e->wev,NULL);
+}
+
+/* Remove event handlers when the context gets disconnected. */
+void redisLibEventOnDisconnect(redisContext *c, void *privdata) {
+    ((void)c);
+    redisEvents *e = privdata;
+    event_del(&e->rev);
+    event_del(&e->wev);
+}
+
+/* Free the redisEvents struct when the context is free'd. */
+void redisLibEventOnFree(redisContext *c, void *privdata) {
+    ((void)c);
+    redisEvents *e = privdata;
+    free(e);
+}
+
+redisContext *redisLibEventConnect(const char *ip, int port, redisErrorCallback *err) {
+    redisEvents *e;
+    redisContext *c = redisConnectNonBlock(ip, port, NULL);
+    if (c->error != NULL) {
+        err(c);
+        return NULL;
+    }
+
+    /* Create container for context and r/w events */
+    e = malloc(sizeof(*e));
+    e->context = c;
+    e->err = err;
+
+    /* Register callbacks and events */
+    redisSetDisconnectCallback(e->context, redisLibEventOnDisconnect, e);
+    redisSetCommandCallback(e->context, redisLibEventOnWrite, e);
+    redisSetFreeCallback(e->context, redisLibEventOnFree, e);
+    event_set(&e->rev, e->context->fd, EV_READ, redisLibEventRead, e);
+    event_set(&e->wev, e->context->fd, EV_WRITE, redisLibEventWrite, e);
+    return e->context;
+}