Markus Koetter's adaptation of hiperfifo.c to instead use libev

1 files changed, 460 insertions, 0 deletions

diff --git a/docs/examples/evhiperfifo.c b/docs/examples/evhiperfifo.c
new file mode 100644
index 000000000..e77715aae
--- /dev/null
+++ b/docs/examples/evhiperfifo.c
@@ -0,0 +1,460 @@
+/*****************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * $Id$
+ *
+ * Example application source code using the multi socket interface to
+ * download many files at once.
+ *
+ * This example features the same basic functionality as hiperfifo.c does,
+ * but this uses libev instead of libevent.
+ *
+ * Written by Jeff Pohlmeyer, converted to use libev by Markus Koetter
+
+Requires libev and a (POSIX?) system that has mkfifo().
+
+This is an adaptation of libcurl's "hipev.c" and libevent's "event-test.c"
+sample programs.
+
+When running, the program creates the named pipe "hiper.fifo"
+
+Whenever there is input into the fifo, the program reads the input as a list
+of URL's and creates some new easy handles to fetch each URL via the
+curl_multi "hiper" API.
+
+
+Thus, you can try a single URL:
+  % echo http://www.yahoo.com > hiper.fifo
+
+Or a whole bunch of them:
+  % cat my-url-list > hiper.fifo
+
+The fifo buffer is handled almost instantly, so you can even add more URL's
+while the previous requests are still being downloaded.
+
+Note:
+  For the sake of simplicity, URL length is limited to 1023 char's !
+
+This is purely a demo app, all retrieved data is simply discarded by the write
+callback.
+
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/poll.h>
+#include <curl/curl.h>
+#include <ev.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <errno.h>
+
+#define DPRINT(x...) printf(x)
+
+#define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
+
+
+/* Global information, common to all connections */
+typedef struct _GlobalInfo
+{
+  struct ev_loop *loop;
+  struct ev_io fifo_event;
+  struct ev_timer timer_event;
+  CURLM *multi;
+  int prev_running;
+  int still_running;
+  FILE* input;
+} GlobalInfo;
+
+
+/* Information associated with a specific easy handle */
+typedef struct _ConnInfo
+{
+  CURL *easy;
+  char *url;
+  GlobalInfo *global;
+  char error[CURL_ERROR_SIZE];
+} ConnInfo;
+
+
+/* Information associated with a specific socket */
+typedef struct _SockInfo
+{
+  curl_socket_t sockfd;
+  CURL *easy;
+  int action;
+  long timeout;
+  struct ev_io ev;
+  int evset;
+  GlobalInfo *global;
+} SockInfo;
+
+static void timer_cb(EV_P_ struct ev_timer *w, int revents);
+
+/* Update the event timer after curl_multi library calls */
+static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g)
+{
+  DPRINT("%s %li\n", __PRETTY_FUNCTION__,  timeout_ms);
+  ev_timer_stop(g->loop, &g->timer_event);
+  if (timeout_ms > 0)
+  {
+    double  t = timeout_ms / 1000;
+    ev_timer_init(&g->timer_event, timer_cb, t, 0.);
+    ev_timer_start(g->loop, &g->timer_event);
+  }else
+    timer_cb(g->loop, &g->timer_event, 0);
+  return 0;
+}
+
+/* Die if we get a bad CURLMcode somewhere */
+static void mcode_or_die(const char *where, CURLMcode code)
+{
+  if ( CURLM_OK != code )
+  {
+    const char *s;
+    switch ( code )
+    {
+    case CURLM_CALL_MULTI_PERFORM: s="CURLM_CALL_MULTI_PERFORM"; break;
+    case CURLM_OK:                 s="CURLM_OK";                 break;
+    case CURLM_BAD_HANDLE:         s="CURLM_BAD_HANDLE";         break;
+    case CURLM_BAD_EASY_HANDLE:    s="CURLM_BAD_EASY_HANDLE";    break;
+    case CURLM_OUT_OF_MEMORY:      s="CURLM_OUT_OF_MEMORY";      break;
+    case CURLM_INTERNAL_ERROR:     s="CURLM_INTERNAL_ERROR";     break;
+    case CURLM_UNKNOWN_OPTION:     s="CURLM_UNKNOWN_OPTION";     break;
+    case CURLM_LAST:               s="CURLM_LAST";               break;
+    default: s="CURLM_unknown";
+      break;
+    case     CURLM_BAD_SOCKET:         s="CURLM_BAD_SOCKET";
+      fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
+      /* ignore this error */
+      return;
+    }
+    fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
+    exit(code);
+  }
+}
+
+
+
+/* Check for completed transfers, and remove their easy handles */
+static void check_run_count(GlobalInfo *g)
+{
+  DPRINT("%s prev %i still %i\n", __PRETTY_FUNCTION__,
+         g->prev_running, g->still_running);
+  if ( g->prev_running > g->still_running )
+  {
+    char *eff_url=NULL;
+    CURLMsg *msg;
+    int msgs_left;
+    ConnInfo *conn=NULL;
+    CURL*easy;
+    CURLcode res;
+
+    fprintf(MSG_OUT, "REMAINING: %d\n", g->still_running);
+    /*
+      I am still uncertain whether it is safe to remove an easy
+      handle from inside the curl_multi_info_read loop, so here I
+      will search for completed transfers in the inner "while"
+      loop, and then remove them in the outer "do-while" loop...
+    */
+    do
+    {
+      easy=NULL;
+      while ( (msg = curl_multi_info_read(g->multi, &msgs_left)) )
+      {
+        if ( msg->msg == CURLMSG_DONE )
+        {
+          easy=msg->easy_handle;
+          res=msg->data.result;
+        }
+
+        if ( easy )
+        {
+          curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
+          curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
+          fprintf(MSG_OUT, "DONE: %s => (%d) %s\n", eff_url, res, conn->error);
+          curl_multi_remove_handle(g->multi, easy);
+          free(conn->url);
+          curl_easy_cleanup(easy);
+          free(conn);
+        }
+      }
+    } while ( easy );
+  }
+  g->prev_running = g->still_running;
+}
+
+
+/* Called by libevent when we get action on a multi socket */
+static void event_cb(EV_P_ struct ev_io *w, int revents)
+{
+  DPRINT("%s  w %p revents %i\n", __PRETTY_FUNCTION__, w, revents);
+  GlobalInfo *g = (GlobalInfo*) w->data;
+  CURLMcode rc;
+
+  int action = (revents&EV_READ?CURL_POLL_IN:0)|
+    (revents&EV_WRITE?CURL_POLL_OUT:0);
+  do
+  {
+    rc = curl_multi_socket_action(g->multi, w->fd, action, &g->still_running);
+  } while ( rc == CURLM_CALL_MULTI_PERFORM );
+  mcode_or_die("event_cb: curl_multi_socket", rc);
+  check_run_count(g);
+  if ( g->still_running <= 0 )
+  {
+    fprintf(MSG_OUT, "last transfer done, kill timeout\n");
+    ev_timer_stop(g->loop, &g->timer_event);
+  }
+}
+
+/* Called by libevent when our timeout expires */
+static void timer_cb(EV_P_ struct ev_timer *w, int revents)
+{
+  DPRINT("%s  w %p revents %i\n", __PRETTY_FUNCTION__, w, revents);
+
+  GlobalInfo *g = (GlobalInfo *)w->data;
+  CURLMcode rc;
+
+  do
+  {
+    rc = curl_multi_socket_action(g->multi, CURL_SOCKET_TIMEOUT, 0, &g->still_running);
+  } while ( rc == CURLM_CALL_MULTI_PERFORM );
+  mcode_or_die("timer_cb: curl_multi_socket", rc);
+  check_run_count(g);
+}
+
+/* Clean up the SockInfo structure */
+static void remsock(SockInfo *f, GlobalInfo *g)
+{
+  printf("%s  \n", __PRETTY_FUNCTION__);
+  if ( f )
+  {
+    if ( f->evset )
+      ev_io_stop(g->loop, &f->ev);
+    free(f);
+  }
+}
+
+
+
+/* Assign information to a SockInfo structure */
+static void setsock(SockInfo*f, curl_socket_t s, CURL*e, int act, GlobalInfo*g)
+{
+  printf("%s  \n", __PRETTY_FUNCTION__);
+
+  int kind = (act&CURL_POLL_IN?EV_READ:0)|(act&CURL_POLL_OUT?EV_WRITE:0);
+
+  f->sockfd = s;
+  f->action = act;
+  f->easy = e;
+  if ( f->evset )
+    ev_io_stop(g->loop, &f->ev);
+  ev_io_init(&f->ev, event_cb, f->sockfd, kind);
+  f->ev.data = g;
+  f->evset=1;
+  ev_io_start(g->loop, &f->ev);
+}
+
+
+
+/* Initialize a new SockInfo structure */
+static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
+{
+  SockInfo *fdp = calloc(sizeof(SockInfo), 1);
+
+  fdp->global = g;
+  setsock(fdp, s, easy, action, g);
+  curl_multi_assign(g->multi, s, fdp);
+}
+
+/* CURLMOPT_SOCKETFUNCTION */
+static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
+{
+  DPRINT("%s e %p s %i what %i cbp %p sockp %p\n",
+         __PRETTY_FUNCTION__, e, s, what, cbp, sockp);
+
+  GlobalInfo *g = (GlobalInfo*) cbp;
+  SockInfo *fdp = (SockInfo*) sockp;
+  const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE"};
+
+  fprintf(MSG_OUT,
+          "socket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
+  if ( what == CURL_POLL_REMOVE )
+  {
+    fprintf(MSG_OUT, "\n");
+    remsock(fdp, g);
+  } else
+  {
+    if ( !fdp )
+    {
+      fprintf(MSG_OUT, "Adding data: %s\n", whatstr[what]);
+      addsock(s, e, what, g);
+    } else
+    {
+      fprintf(MSG_OUT,
+              "Changing action from %s to %s\n",
+              whatstr[fdp->action], whatstr[what]);
+      setsock(fdp, s, e, what, g);
+    }
+  }
+  return 0;
+}
+
+
+/* CURLOPT_WRITEFUNCTION */
+static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data)
+{
+  size_t realsize = size * nmemb;
+  ConnInfo *conn = (ConnInfo*) data;
+  (void)ptr;
+  (void)conn;
+  return realsize;
+}
+
+
+/* CURLOPT_PROGRESSFUNCTION */
+static int prog_cb (void *p, double dltotal, double dlnow, double ult,
+                    double uln)
+{
+  ConnInfo *conn = (ConnInfo *)p;
+  (void)ult;
+  (void)uln;
+
+  fprintf(MSG_OUT, "Progress: %s (%g/%g)\n", conn->url, dlnow, dltotal);
+  return 0;
+}
+
+
+/* Create a new easy handle, and add it to the global curl_multi */
+static void new_conn(char *url, GlobalInfo *g )
+{
+  ConnInfo *conn;
+  CURLMcode rc;
+
+  conn = calloc(1, sizeof(ConnInfo));
+  memset(conn, 0, sizeof(ConnInfo));
+  conn->error[0]='\0';
+
+  conn->easy = curl_easy_init();
+  if ( !conn->easy )
+  {
+    fprintf(MSG_OUT, "curl_easy_init() failed, exiting!\n");
+    exit(2);
+  }
+  conn->global = g;
+  conn->url = strdup(url);
+  curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
+  curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
+  curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, &conn);
+  curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
+  curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
+  curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
+  curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 0L);
+  curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
+  curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
+  curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_TIME, 3L);
+  curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_LIMIT, 10L);
+
+  fprintf(MSG_OUT,
+          "Adding easy %p to multi %p (%s)\n", conn->easy, g->multi, url);
+  rc =curl_multi_add_handle(g->multi, conn->easy);
+  mcode_or_die("new_conn: curl_multi_add_handle", rc);
+
+  mcode_or_die("new_conn: curl_multi_socket_all", rc);
+  check_run_count(g);
+}
+
+/* This gets called whenever data is received from the fifo */
+static void fifo_cb(EV_P_ struct ev_io *w, int revents)
+{
+  char s[1024];
+  long int rv=0;
+  int n=0;
+  GlobalInfo *g = (GlobalInfo *)w->data;
+
+  do
+  {
+    s[0]='\0';
+    rv=fscanf(g->input, "%1023s%n", s, &n);
+    s[n]='\0';
+    if ( n && s[0] )
+    {
+      new_conn(s,g);  /* if we read a URL, go get it! */
+    } else break;
+  } while ( rv != EOF );
+}
+
+/* Create a named pipe and tell libevent to monitor it */
+static int init_fifo (GlobalInfo *g)
+{
+  struct stat st;
+  static const char *fifo = "hiper.fifo";
+  int sockfd;
+
+  fprintf(MSG_OUT, "Creating named pipe \"%s\"\n", fifo);
+  if ( lstat (fifo, &st) == 0 )
+  {
+    if ( (st.st_mode & S_IFMT) == S_IFREG )
+    {
+      errno = EEXIST;
+      perror("lstat");
+      exit (1);
+    }
+  }
+  unlink(fifo);
+  if ( mkfifo (fifo, 0600) == -1 )
+  {
+    perror("mkfifo");
+    exit (1);
+  }
+  sockfd = open(fifo, O_RDWR | O_NONBLOCK, 0);
+  if ( sockfd == -1 )
+  {
+    perror("open");
+    exit (1);
+  }
+  g->input = fdopen(sockfd, "r");
+
+  fprintf(MSG_OUT, "Now, pipe some URL's into > %s\n", fifo);
+  ev_io_init(&g->fifo_event, fifo_cb, sockfd, EV_READ);
+  ev_io_start(g->loop, &g->fifo_event);
+  return(0);
+}
+
+int main(int argc, char **argv)
+{
+  GlobalInfo g;
+  CURLMcode rc;
+  (void)argc;
+  (void)argv;
+
+  memset(&g, 0, sizeof(GlobalInfo));
+  g.loop = ev_default_loop(0);
+
+  init_fifo(&g);
+  g.multi = curl_multi_init();
+
+  ev_timer_init(&g.timer_event, timer_cb, 0., 0.);
+  g.timer_event.data = &g;
+  g.fifo_event.data = &g;
+  curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
+  curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
+  curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
+  curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
+  do
+  {
+    rc = curl_multi_socket_all(g.multi, &g.still_running);
+  } while ( CURLM_CALL_MULTI_PERFORM == rc );
+
+  ev_loop(g.loop, 0);
+  curl_multi_cleanup(g.multi);
+  return 0;
+}