Factor out reusable include for libevent

Makefile

@@ -58,14 +58,14 @@ hiredis-%: %.o ${DYLIBNAME}
 test: hiredis-test
 	./hiredis-test
 
-libevent-example: libevent-example.c ${DYLIBNAME}
+libevent-example: extra/hiredis/libevent.h libevent-example.c ${DYLIBNAME}
-	$(CC) -o $@ $(CCOPT) $(DEBUG) -L. -lhiredis -levent libevent-example.c
+	$(CC) -o $@ $(CCOPT) $(DEBUG) -I. -Iextra -L. -lhiredis -levent libevent-example.c
 
 .c.o:
 	$(CC) -c $(CFLAGS) $(DEBUG) $(COMPILE_TIME) $<
 
 clean:
-	rm -rf ${DYLIBNAME} ${STLIBNAME} $(BINS) *.o *.gcda *.gcno *.gcov
+	rm -rf ${DYLIBNAME} ${STLIBNAME} $(BINS) libevent-example *.o *.gcda *.gcno *.gcov
 
 dep:
 	$(CC) -MM *.c

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;
+}

libevent-example.c

@@ -1,96 +1,32 @@
 #include <stdio.h>
 #include <stdlib.h>
-#include <event.h>
 #include <string.h>
-#include "hiredis.h"
+#include <hiredis/libevent.h>
 
-#define NOT_USED(x) ((void)x)
+void getCallback(redisContext *c, redisReply *reply, const void *privdata) {
+    printf("argv[%s]: %s\n", (const char*)privdata, reply->reply);
 
-/* This struct enables us to pass both the event and the
+    /* Disconnect after receiving the reply to GET */
- * redisContext to the read and write handlers. */
+    redisDisconnect(c);
-typedef struct redisEvents {
-    redisContext *context;
-    struct event rev, wev;
-} redisEvents;
-
-void redisLibEventRead(int fd, short event, void *arg) {
-    NOT_USED(fd); NOT_USED(event);
-    redisEvents *e = arg;
-
-    /* Always re-schedule read events */
-    event_add(&e->rev,NULL);
-
-    if (redisBufferRead(e->context) == REDIS_ERR) {
-        /* Handle error. */
-        printf("Read error: %s\n", e->context->error);
-    } else {
-        /* Check replies. */
-        redisProcessCallbacks(e->context);
-    }
 }
 
-void redisLibEventWrite(int fd, short event, void *arg) {
+void errorCallback(redisContext *c) {
-    NOT_USED(fd); NOT_USED(event);
+    printf("Error: %s\n", c->error);
-    redisEvents *e = arg;
-    int done = 0;
 
-    if (redisBufferWrite(e->context, &done) == REDIS_ERR) {
+    /* Clean up the context when there was an error */
-        /* Handle error */
-        printf("Write error: %s\n", e->context->error);
-    } 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) {
-    NOT_USED(c);
-    redisEvents *e = privdata;
-    event_add(&e->wev,NULL);
-}
-
-/* Free the redisEvents struct when the context is free'd. */
-void redisLibEventOnFree(redisContext *c, void *privdata) {
-    NOT_USED(c);
-    redisEvents *e = privdata;
-    free(e);
-}
-
-redisContext *redisLibEventConnect(const char *ip, int port) {
-    redisEvents *e = malloc(sizeof(*e));
-    e->context = redisConnectNonBlock(ip, port, NULL);
-    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;
-}
-
-void getCallback(redisContext *c, redisReply *reply, void *privdata) {
-    NOT_USED(c); NOT_USED(privdata);
-    printf("argv[end-1]: %s\n", reply->reply);
     redisFree(c);
-    exit(0);
 }
 
 int main (int argc, char **argv) {
     signal(SIGPIPE, SIG_IGN);
     event_init();
 
-    redisContext *c = redisLibEventConnect("127.0.0.1", 6379);
+    redisContext *c = redisLibEventConnect("127.0.0.1", 6379, errorCallback);
-    if (c->error != NULL) {
+    if (c == NULL) return 1;
-        printf("Connection error: %s\n", c->error);
-        return 1;
-    }
 
     redisCommand(c, "SET key %b", argv[argc-1], strlen(argv[argc-1]));
-    redisCommandWithCallback(c, getCallback, NULL, "GET key");
+    redisCommandWithCallback(c, getCallback, "end-1", "GET key");
     event_dispatch();
+    redisFree(c);
     return 0;
 }