/*
  * Unbuffered io for ffmpeg system

  * Copyright (c) 2001 Fabrice Bellard

  *

  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either

  * version 2.1 of the License, or (at your option) any later version.

  *

  * FFmpeg 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
  * Lesser General Public License for more details.

  *

  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  */

 #include <unistd.h>

 #include "libavutil/avstring.h"

 #include "libavutil/opt.h"

 #include "os_support.h"

 #include "avformat.h"

 #if CONFIG_NETWORK
 #include "network.h"
 #endif

 #include "url.h"

 
 /** @name Logging context. */
 /*@{*/
 static const char *urlcontext_to_name(void *ptr)
 {
     URLContext *h = (URLContext *)ptr;
     if(h->prot) return h->prot->name;
     else        return "NULL";
 }
 static const AVOption options[] = {{NULL}};

 static const AVClass urlcontext_class = {
     .class_name     = "URLContext",
     .item_name      = urlcontext_to_name,
     .option         = options,
     .version        = LIBAVUTIL_VERSION_INT,
 };

 /*@}*/

 static int default_interrupt_cb(void);
 

 URLProtocol *first_protocol = NULL;

 int (*url_interrupt_cb)(void) = default_interrupt_cb;

 URLProtocol *av_protocol_next(URLProtocol *p)
 {
     if(p) return p->next;
     else  return first_protocol;
 }
 

 const char *avio_enum_protocols(void **opaque, int output)
 {

     URLProtocol *p = *opaque;
     p = p ? p->next : first_protocol;
     if (!p) return NULL;
     if ((output && p->url_write) || (!output && p->url_read))
         return p->name;

     return avio_enum_protocols(opaque, output);

 }
 

 int ffurl_register_protocol(URLProtocol *protocol, int size)

 {
     URLProtocol **p;

     if (size < sizeof(URLProtocol)) {
         URLProtocol* temp = av_mallocz(sizeof(URLProtocol));
         memcpy(temp, protocol, size);
         protocol = temp;
     }

     p = &first_protocol;
     while (*p != NULL) p = &(*p)->next;
     *p = protocol;
     protocol->next = NULL;
     return 0;
 }
 

 static int url_alloc_for_protocol (URLContext **puc, struct URLProtocol *up,

                                    const char *filename, int flags)

 {
     URLContext *uc;
     int err;
 

 #if CONFIG_NETWORK
     if (!ff_network_init())
         return AVERROR(EIO);
 #endif

     uc = av_mallocz(sizeof(URLContext) + strlen(filename) + 1);

     if (!uc) {

         err = AVERROR(ENOMEM);

         goto fail;
     }

     uc->av_class = &urlcontext_class;

     uc->filename = (char *) &uc[1];

     strcpy(uc->filename, filename);

     uc->prot = up;
     uc->flags = flags;
     uc->is_streamed = 0; /* default = not streamed */

     uc->max_packet_size = 0; /* default: stream file */

     if (up->priv_data_size) {
         uc->priv_data = av_mallocz(up->priv_data_size);
         if (up->priv_data_class) {

             *(const AVClass**)uc->priv_data = up->priv_data_class;

             av_opt_set_defaults(uc->priv_data);
         }
     }

     *puc = uc;
     return 0;

  fail:
     *puc = NULL;

 #if CONFIG_NETWORK
     ff_network_close();
 #endif

     return err;

 }
 

 int ffurl_connect(URLContext* uc)

 {
     int err = uc->prot->url_open(uc, uc->filename, uc->flags);
     if (err)
         return err;
     uc->is_connected = 1;

     //We must be careful here as ffurl_seek() could be slow, for example for http

     if(   (uc->flags & AVIO_FLAG_WRITE)

        || !strcmp(uc->prot->name, "file"))

         if(!uc->is_streamed && ffurl_seek(uc, 0, SEEK_SET) < 0)

             uc->is_streamed= 1;
     return 0;
 }
 

 #if FF_API_OLD_AVIO

 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
                        const char *filename, int flags)
 {
     int ret;
 
     ret = url_alloc_for_protocol(puc, up, filename, flags);
     if (ret)
         goto fail;

     ret = ffurl_connect(*puc);

     if (!ret)
         return 0;
  fail:

     ffurl_close(*puc);

     *puc = NULL;
     return ret;
 }

 int url_alloc(URLContext **puc, const char *filename, int flags)
 {
     return ffurl_alloc(puc, filename, flags);
 }

 int url_connect(URLContext* uc)
 {
     return ffurl_connect(uc);
 }

 int url_open(URLContext **puc, const char *filename, int flags)
 {
     return ffurl_open(puc, filename, flags);
 }

 int url_read(URLContext *h, unsigned char *buf, int size)
 {
     return ffurl_read(h, buf, size);
 }

 int url_read_complete(URLContext *h, unsigned char *buf, int size)
 {
     return ffurl_read_complete(h, buf, size);
 }

 int url_write(URLContext *h, const unsigned char *buf, int size)
 {
     return ffurl_write(h, buf, size);
 }

 int64_t url_seek(URLContext *h, int64_t pos, int whence)
 {
     return ffurl_seek(h, pos, whence);
 }

 int url_close(URLContext *h)
 {
     return ffurl_close(h);
 }

 int64_t url_filesize(URLContext *h)
 {
     return ffurl_size(h);
 }

 int url_get_file_handle(URLContext *h)
 {
     return ffurl_get_file_handle(h);
 }

 int url_get_max_packet_size(URLContext *h)
 {
     return h->max_packet_size;
 }

 void url_get_filename(URLContext *h, char *buf, int buf_size)
 {
     av_strlcpy(buf, h->filename, buf_size);
 }

 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb)
 {
     avio_set_interrupt_cb(interrupt_cb);
 }

 int av_register_protocol2(URLProtocol *protocol, int size)
 {
     return ffurl_register_protocol(protocol, size);
 }

 #endif

 #define URL_SCHEME_CHARS                        \
     "abcdefghijklmnopqrstuvwxyz"                \
     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"                \
     "0123456789+-."
 

 int ffurl_alloc(URLContext **puc, const char *filename, int flags)

 {
     URLProtocol *up;

     char proto_str[128], proto_nested[128], *ptr;

     size_t proto_len = strspn(filename, URL_SCHEME_CHARS);
 
     if (filename[proto_len] != ':' || is_dos_path(filename))

         strcpy(proto_str, "file");

     else
         av_strlcpy(proto_str, filename, FFMIN(proto_len+1, sizeof(proto_str)));

     av_strlcpy(proto_nested, proto_str, sizeof(proto_nested));
     if ((ptr = strchr(proto_nested, '+')))
         *ptr = '\0';
 

     up = first_protocol;
     while (up != NULL) {
         if (!strcmp(proto_str, up->name))

             return url_alloc_for_protocol (puc, up, filename, flags);

         if (up->flags & URL_PROTOCOL_FLAG_NESTED_SCHEME &&
             !strcmp(proto_nested, up->name))
             return url_alloc_for_protocol (puc, up, filename, flags);

         up = up->next;
     }
     *puc = NULL;
     return AVERROR(ENOENT);
 }
 

 int ffurl_open(URLContext **puc, const char *filename, int flags)

 {

     int ret = ffurl_alloc(puc, filename, flags);

     if (ret)
         return ret;

     ret = ffurl_connect(*puc);

     if (!ret)
         return 0;

     ffurl_close(*puc);

     *puc = NULL;
     return ret;
 }
 

 static inline int retry_transfer_wrapper(URLContext *h, unsigned char *buf, int size, int size_min,

                                          int (*transfer_func)(URLContext *h, unsigned char *buf, int size))

 {
     int ret, len;

     int fast_retries = 5;

 
     len = 0;

     while (len < size_min) {

         ret = transfer_func(h, buf+len, size-len);

         if (ret == AVERROR(EINTR))
             continue;

         if (h->flags & AVIO_FLAG_NONBLOCK)

             return ret;

         if (ret == AVERROR(EAGAIN)) {
             ret = 0;

             if (fast_retries)
                 fast_retries--;
             else
                 usleep(1000);

         } else if (ret < 1)
             return ret < 0 ? ret : len;

         if (ret)
            fast_retries = FFMAX(fast_retries, 2);

         len += ret;

         if (len < size && url_interrupt_cb())

             return AVERROR_EXIT;

     }
     return len;
 }
 

 int ffurl_read(URLContext *h, unsigned char *buf, int size)

 {

     if (!(h->flags & AVIO_FLAG_READ))

         return AVERROR(EIO);
     return retry_transfer_wrapper(h, buf, size, 1, h->prot->url_read);
 }
 

 int ffurl_read_complete(URLContext *h, unsigned char *buf, int size)

 {

     if (!(h->flags & AVIO_FLAG_READ))

         return AVERROR(EIO);
     return retry_transfer_wrapper(h, buf, size, size, h->prot->url_read);

 }
 

 int ffurl_write(URLContext *h, const unsigned char *buf, int size)

 {

     if (!(h->flags & AVIO_FLAG_WRITE))

         return AVERROR(EIO);

     /* avoid sending too big packets */
     if (h->max_packet_size && size > h->max_packet_size)

         return AVERROR(EIO);

     return retry_transfer_wrapper(h, buf, size, size, (void*)h->prot->url_write);

 }
 

 int64_t ffurl_seek(URLContext *h, int64_t pos, int whence)

 {

     int64_t ret;

 
     if (!h->prot->url_seek)

         return AVERROR(ENOSYS);

     ret = h->prot->url_seek(h, pos, whence & ~AVSEEK_FORCE);

     return ret;
 }
 

 int ffurl_close(URLContext *h)

 {

     int ret = 0;

     if (!h) return 0; /* can happen when ffurl_open fails */

     if (h->is_connected && h->prot->url_close)

         ret = h->prot->url_close(h);

 #if CONFIG_NETWORK
     ff_network_close();
 #endif

     if (h->prot->priv_data_size)
         av_free(h->priv_data);

     av_free(h);

     return ret;
 }
 

 #if FF_API_OLD_AVIO

 int url_exist(const char *filename)
 {
     URLContext *h;

     if (ffurl_open(&h, filename, AVIO_FLAG_READ) < 0)

         return 0;

     ffurl_close(h);

     return 1;
 }

 #endif

 int avio_check(const char *url, int flags)
 {
     URLContext *h;
     int ret = ffurl_alloc(&h, url, flags);
     if (ret)
         return ret;
 
     if (h->prot->url_check) {
         ret = h->prot->url_check(h, flags);
     } else {
         ret = ffurl_connect(h);
         if (ret >= 0)
             ret = flags;
     }
 
     ffurl_close(h);
     return ret;
 }

 int64_t ffurl_size(URLContext *h)

 {

     int64_t pos, size;

     size= ffurl_seek(h, 0, AVSEEK_SIZE);

     if(size<0){

         pos = ffurl_seek(h, 0, SEEK_CUR);
         if ((size = ffurl_seek(h, -1, SEEK_END)) < 0)

             return size;
         size++;

         ffurl_seek(h, pos, SEEK_SET);

     }

     return size;
 }

 int ffurl_get_file_handle(URLContext *h)

 {
     if (!h->prot->url_get_file_handle)
         return -1;
     return h->prot->url_get_file_handle(h);
 }
 

 static int default_interrupt_cb(void)
 {
     return 0;
 }
 

 void avio_set_interrupt_cb(int (*interrupt_cb)(void))

 {
     if (!interrupt_cb)
         interrupt_cb = default_interrupt_cb;
     url_interrupt_cb = interrupt_cb;
 }

 #if FF_API_OLD_AVIO

 int av_url_read_pause(URLContext *h, int pause)

 {
     if (!h->prot->url_read_pause)
         return AVERROR(ENOSYS);

     return h->prot->url_read_pause(h, pause);

 }
 

 int64_t av_url_read_seek(URLContext *h,

         int stream_index, int64_t timestamp, int flags)
 {
     if (!h->prot->url_read_seek)
         return AVERROR(ENOSYS);
     return h->prot->url_read_seek(h, stream_index, timestamp, flags);
 }

 #endif