lca2011: turn it into a true Usenet Oracle.

[ccan-lca-2011.git] / ccan / oserver / oserver.c

diff --git a/ccan/oserver/oserver.c b/ccan/oserver/oserver.c
index 9e1f2b0b6b46d421218b92187c9b5d19d7921700..2d4cac41b28754fbef15a07f952edf5eb5109b0d 100644 (file)
--- a/ccan/oserver/oserver.c
+++ b/ccan/oserver/oserver.c
@@ -15,10 +15,16 @@
 #include <string.h>
 #include <errno.h>
 #include <signal.h>
+#include <assert.h>
 
 enum state {
        SENDING_GREETING,
        RECEIVING_USER_QUESTION,
+       AWAITING_A_SUBCLIENT,
+       SENDING_OTHER_QUESTION_PREFIX,
+       SENDING_OTHER_QUESTION,
+       RECEIVING_OTHER_ANSWER,
+       AWAITING_OUR_ORACLE,
        SENDING_ANSWER_PREFIX,
        SENDING_ANSWER,
        FINISHED
@@ -27,6 +33,11 @@ enum state {
 static uint16_t state_flag_map[] = {
        [SENDING_GREETING]              = TEVENT_FD_WRITE,
        [RECEIVING_USER_QUESTION]       = TEVENT_FD_READ,
+       [AWAITING_A_SUBCLIENT]          = 0,
+       [SENDING_OTHER_QUESTION_PREFIX] = TEVENT_FD_WRITE,
+       [SENDING_OTHER_QUESTION]        = TEVENT_FD_WRITE,
+       [RECEIVING_OTHER_ANSWER]        = TEVENT_FD_READ,
+       [AWAITING_OUR_ORACLE]           = 0,
        [SENDING_ANSWER_PREFIX]         = TEVENT_FD_WRITE,
        [SENDING_ANSWER]                = TEVENT_FD_WRITE,
        [FINISHED]                      = 0
@@ -41,11 +52,15 @@ struct client {
        /* The question we read from client. */
        char *question;
        /* The answer to the client. */
-       const char *answer;
+       char *answer;
        /* How many bytes of the reply we sent so far. */
        size_t bytes_sent;
        /* Our server. */
        struct oserver *oserver;
+       /* Whose question this client is answering. */
+       struct client *subclient;
+       /* Who is answering our question. */
+       struct client *oracle;
 };
 
 struct oserver {
@@ -53,7 +68,6 @@ struct oserver {
        struct client *clients[5];
        int fd;
        struct tevent_fd *fde;
-       const char *last_answer;
 };
 
 static ssize_t write_string(int fd, const char *str)
@@ -105,6 +119,40 @@ static bool send_string(struct client *c, const char *str)
        return true;
 }
 
+static bool get_subclient(struct client *me)
+{
+       unsigned int i;
+
+       for (i = 0; i < ARRAY_SIZE(me->oserver->clients); i++) {
+               struct client *c = me->oserver->clients[i];
+               if (!c || c == me)
+                       continue;
+               if (c->oracle == NULL && input_finished(c->question)) {
+                       me->subclient = c;
+                       c->oracle = me;
+                       return true;
+               }
+       }
+       return false;
+}
+
+static bool get_oracle(struct client *me)
+{
+       unsigned int i;
+
+       for (i = 0; i < ARRAY_SIZE(me->oserver->clients); i++) {
+               struct client *c = me->oserver->clients[i];
+               if (!c || c == me)
+                       continue;
+               if (c->subclient == NULL && input_finished(c->question)) {
+                       me->oracle = c;
+                       c->subclient = me;
+                       return true;
+               }
+       }
+       return false;
+}
+
 static void service_client(struct tevent_context *ev,
                           struct tevent_fd *fde, uint16_t flags, void *_c)
 {
@@ -121,14 +169,50 @@ static void service_client(struct tevent_context *ev,
                if (len <= 0)
                        goto fail;
                if (input_finished(c->question)) {
-                       c->answer = talloc_steal(c, c->oserver->last_answer);
-                       c->oserver->last_answer
-                               = talloc_steal(c->oserver, c->question);
-                       set_state(c, SENDING_ANSWER_PREFIX);
+                       /* Look for someone to be oracle to. */
+                       if (get_subclient(c)) {
+                               set_state(c, SENDING_OTHER_QUESTION_PREFIX);
+                       } else {
+                               /* We sit here until someone find_oracles us */
+                               set_state(c, AWAITING_A_SUBCLIENT);
+                       }
+
+                       /* Look for an oracle for ourselves. */
+                       if (get_oracle(c)) {
+                               assert(c->oracle->state
+                                      == AWAITING_A_SUBCLIENT);
+                               set_state(c->oracle,
+                                         SENDING_OTHER_QUESTION_PREFIX);
+                       }
+               }
+               break;
+       case SENDING_OTHER_QUESTION_PREFIX:
+               if (!send_string(c, "While the Oracle ponders,"
+                                " please answer the following question:\n"))
+                       goto fail;
+               break;
+       case SENDING_OTHER_QUESTION:
+               if (!send_string(c, c->subclient->question))
+                       goto fail;
+               break;
+       case RECEIVING_OTHER_ANSWER:
+               len = read_string(c->fd, &c->subclient->answer);
+               if (len <= 0)
+                       goto fail;
+               if (input_finished(c->subclient->answer)) {
+                       /* Did our oracle answer for us already? */
+                       if (input_finished(c->answer))
+                               set_state(c, SENDING_ANSWER_PREFIX);
+                       else
+                               set_state(c, AWAITING_OUR_ORACLE);
+
+                       /* If they were waiting for an answer, move them. */
+                       if (c->subclient->state == AWAITING_OUR_ORACLE)
+                               set_state(c->subclient, SENDING_ANSWER_PREFIX);
                }
                break;
        case SENDING_ANSWER_PREFIX:
-               if (!send_string(c, "I believe a better question is "))
+               if (!send_string(c, "The Oracle spake thus:\n"))
                        goto fail;
                break;
        case SENDING_ANSWER:
@@ -177,6 +261,9 @@ static void add_client(struct tevent_context *ev,
        client->bytes_sent = 0;
        client->question = talloc_strdup(client, "");
        client->oserver = oserver;
+       client->oracle = NULL;
+       client->subclient = NULL;
+       client->answer = talloc_strdup(client, "");
        client->fde = tevent_add_fd(ev, client, client->fd,
                                    state_flag_map[client->state],
                                    service_client, client);
@@ -220,9 +307,6 @@ struct oserver *oserver_setup(struct tevent_context *ev, unsigned short port)
                talloc_free(oserver);
                return NULL;
        }
-       oserver->last_answer = talloc_strdup(oserver,
-                                            "how many manly men mendaciously"
-                                            " mention mending mansions?\n");
 
        talloc_set_destructor(oserver, destroy_oserver);