FFmpeg "evbuffer:0x..." URLProtocol implementation

Implement a URL handler to output data to an evbuffer from ffmpeg.

src/Makefile.am

@@ -39,6 +39,7 @@ forked_daapd_SOURCES = main.c \
 	remote_pairing.c remote_pairing.h \
 	evhttp/http.c evhttp/evhttp.h \
 	evhttp/http-internal.h evhttp/log.h \
+	ffmpeg_url_evbuffer.c ffmpeg_url_evbuffer.h \
 	httpd.c httpd.h \
 	httpd_rsp.c httpd_rsp.h \
 	httpd_daap.c httpd_daap.h \

src/ffmpeg_url_evbuffer.c

@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2010 Julien BLACHE <jb@jblache.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdlib.h>
+
+#include <libavformat/avformat.h>
+
+#include <event.h>
+
+#include "logger.h"
+#include "ffmpeg_url_evbuffer.h"
+
+/*
+ * FFmpeg URL Protocol handler for evbuffers
+ *
+ * URL: evbuffer:0x03FB33DA ("evbuffer:%p")
+ */
+
+
+static int
+url_evbuffer_open(URLContext *h, const char *filename, int flags)
+{
+  const char *p;
+  char *end;
+  unsigned long evbuffer_addr;
+
+  if (flags != URL_WRONLY)
+    {
+      DPRINTF(E_LOG, L_FFMPEG, "Flags other than URL_WRONLY not supported while opening '%s'\n", filename);
+
+      return AVERROR(EIO);
+    }
+
+  p = strchr(filename, ':');
+  if (!p)
+    {
+      DPRINTF(E_LOG, L_FFMPEG, "Malformed evbuffer URL: '%s'\n", filename);
+
+      return AVERROR(EIO);
+    }
+
+  p++;
+
+  errno = 0;
+  evbuffer_addr = strtoul(p, &end, 16);
+  if (((errno == ERANGE) && (evbuffer_addr == ULONG_MAX))
+      || ((errno != 0) && (evbuffer_addr == 0)))
+    {
+      DPRINTF(E_LOG, L_FFMPEG, "Invalid buffer address in URL: '%s'\n", filename);
+
+      return AVERROR(EIO);
+    }
+
+  if (end == p)
+    {
+      DPRINTF(E_LOG, L_FFMPEG, "No buffer address found in URL: '%s'\n", filename);
+
+      return AVERROR(EIO);
+    }
+
+  h->priv_data = (void *)evbuffer_addr;
+  if (!h->priv_data)
+    {
+      DPRINTF(E_LOG, L_FFMPEG, "Got a NULL buffer address from URL '%s'\n", filename);
+
+      return AVERROR(EIO);
+    }
+
+  /* Seek not supported */
+  h->is_streamed = 1;
+
+  return 0;
+}
+
+static int
+url_evbuffer_close(URLContext *h)
+{
+  h->priv_data = NULL;
+
+  return 0;
+}
+
+static int
+url_evbuffer_write(URLContext *h, unsigned char *buf, int size)
+{
+  struct evbuffer *evbuf;
+  int ret;
+
+  evbuf = (struct evbuffer *)h->priv_data;
+
+  if (!evbuf)
+    {
+      DPRINTF(E_LOG, L_FFMPEG, "Write called on evbuffer URL with priv_data = NULL!\n");
+
+      return -1;
+    }
+
+  ret = evbuffer_add(evbuf, buf, size);
+
+  return (ret == 0) ? size : -1;
+}
+
+URLProtocol evbuffer_protocol = {
+  .name      = "evbuffer",
+  .url_open  = url_evbuffer_open,
+  .url_close = url_evbuffer_close,
+  .url_write = url_evbuffer_write,
+};
+
+int
+register_ffmpeg_evbuffer_url_protocol(void)
+{
+  int ret;
+
+  ret = av_register_protocol(&evbuffer_protocol);
+
+  return ret;
+}

src/ffmpeg_url_evbuffer.h

@@ -0,0 +1,8 @@
+
+#ifndef __FFMPEG_URL_EVBUFFER_H__
+#define __FFMPEG_URL_EVBUFFER_H__
+
+int
+register_ffmpeg_evbuffer_url_protocol(void);
+
+#endif /* !__FFMPEG_URL_EVBUFFER_H__ */