/* File retrieval.
   Copyright (C) 1995, 1996, 1997, 1998, 2000, 2001 Free Software Foundation, Inc.

This file is part of GNU Wget.

GNU Wget 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.

GNU Wget 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 Wget; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif /* HAVE_UNISTD_H */
#include <errno.h>
#ifdef HAVE_STRING_H
# include <string.h>
#else
# include <strings.h>
#endif /* HAVE_STRING_H */
#include <assert.h>

#include "wget.h"
#include "utils.h"
#include "retr.h"
#include "progress.h"
#include "url.h"
#include "recur.h"
#include "ftp.h"
#include "host.h"
#include "connect.h"
#include "hash.h"

#ifndef errno
extern int errno;
#endif

/* See the comment in gethttp() why this is needed. */
int global_download_count;


#define MIN(i, j) ((i) <= (j) ? (i) : (j))

/* Reads the contents of file descriptor FD, until it is closed, or a
   read error occurs.  The data is read in 8K chunks, and stored to
   stream fp, which should have been open for writing.  If BUF is
   non-NULL and its file descriptor is equal to FD, flush RBUF first.
   This function will *not* use the rbuf_* functions!

   The EXPECTED argument is passed to show_progress() unchanged, but
   otherwise ignored.

   If opt.verbose is set, the progress is also shown.  RESTVAL
   represents a value from which to start downloading (which will be
   shown accordingly).  If RESTVAL is non-zero, the stream should have
   been open for appending.

   The function exits and returns codes of 0, -1 and -2 if the
   connection was closed, there was a read error, or if it could not
   write to the output stream, respectively.

   IMPORTANT: The function flushes the contents of the buffer in
   rbuf_flush() before actually reading from fd.  If you wish to read
   from fd immediately, flush or discard the buffer.  */
int
get_contents (int fd, FILE *fp, long *len, long restval, long expected,
	      struct rbuf *rbuf, int use_expected)
{
  int res = 0;
  static char c[8192];
  void *progress = NULL;

  *len = restval;
  if (opt.verbose)
    progress = progress_create (restval, expected);

  if (rbuf && RBUF_FD (rbuf) == fd)
    {
      int need_flush = 0;
      while ((res = rbuf_flush (rbuf, c, sizeof (c))) != 0)
	{
	  if (fwrite (c, sizeof (char), res, fp) < res)
	    return -2;
	  if (opt.verbose)
	    progress_update (progress, res);
	  *len += res;
	  need_flush = 1;
	}
      if (need_flush)
	fflush (fp);
      if (ferror (fp))
	return -2;
    }
  /* Read from fd while there is available data.

     Normally, if expected is 0, it means that it is not known how
     much data is expected.  However, if use_expected is specified,
     then expected being zero means exactly that.  */
  while (!use_expected || (*len < expected))
    {
      int amount_to_read = (use_expected
			    ? MIN (expected - *len, sizeof (c))
			    : sizeof (c));
#ifdef HAVE_SSL
		if (rbuf->ssl!=NULL) {
		  res = ssl_iread (rbuf->ssl, c, amount_to_read);
		} else {
#endif /* HAVE_SSL */
		  res = iread (fd, c, amount_to_read);
#ifdef HAVE_SSL
		}
#endif /* HAVE_SSL */
      if (res > 0)
	{
	  fwrite (c, sizeof (char), res, fp);
	  /* Always flush the contents of the network packet.  This
	     should not be adverse to performance, as the network
	     packets typically won't be too tiny anyway.  */
	  fflush (fp);
	  if (ferror (fp))
	    return -2;
	  if (opt.verbose)
	    progress_update (progress, res);
	  *len += res;
	}
      else
	break;
    }
  if (res < -1)
    res = -1;
  if (opt.verbose)
    progress_finish (progress);
  return res;
}

/* Return a printed representation of the download rate, as
   appropriate for the speed.  If PAD is non-zero, strings will be
   padded to the width of 7 characters (xxxx.xx).  */
char *
retr_rate (long bytes, long msecs, int pad)
{
  static char res[20];
  static char *rate_names[] = {"B/s", "KB/s", "MB/s", "GB/s" };
  int units = 0;

  double dlrate = calc_rate (bytes, msecs, &units);
  sprintf (res, pad ? "%7.2f %s" : "%.2f %s", dlrate, rate_names[units]);

  return res;
}

/* Calculate the download rate and trim it as appropriate for the
   speed.  Appropriate means that if rate is greater than 1K/s,
   kilobytes are used, and if rate is greater than 1MB/s, megabytes
   are used.

   UNITS is zero for B/s, one for KB/s, two for MB/s, and three for
   GB/s.  */
double
calc_rate (long bytes, long msecs, int *units)
{
  double dlrate;

  assert (msecs >= 0);
  assert (bytes >= 0);

  if (msecs == 0)
    /* If elapsed time is 0, it means we're under the granularity of
       the timer.  This often happens on systems that use time() for
       the timer.  */
    msecs = wtimer_granularity ();

  dlrate = (double)1000 * bytes / msecs;
  if (dlrate < 1024.0)
    *units = 0;
  else if (dlrate < 1024.0 * 1024.0)
    *units = 1, dlrate /= 1024.0;
  else if (dlrate < 1024.0 * 1024.0 * 1024.0)
    *units = 2, dlrate /= (1024.0 * 1024.0);
  else
    /* Maybe someone will need this one day.  More realistically, it
       will get tickled by buggy timers. */
    *units = 3, dlrate /= (1024.0 * 1024.0 * 1024.0);

  return dlrate;
}

static int
register_redirections_mapper (void *key, void *value, void *arg)
{
  const char *redirected_from = (const char *)key;
  const char *redirected_to   = (const char *)arg;
  if (0 != strcmp (redirected_from, redirected_to))
    register_redirection (redirected_from, redirected_to);
  return 0;
}

/* Register the redirections that lead to the successful download of
   this URL.  This is necessary so that the link converter can convert
   redirected URLs to the local file.  */

static void
register_all_redirections (struct hash_table *redirections, const char *final)
{
  hash_table_map (redirections, register_redirections_mapper, (void *)final);
}

#define USE_PROXY_P(u) (opt.use_proxy && getproxy((u)->scheme)		\
			&& no_proxy_match((u)->host,			\
					  (const char **)opt.no_proxy))

/* Retrieve the given URL.  Decides which loop to call -- HTTP(S), FTP,
   or simply copy it with file:// (#### the latter not yet
   implemented!).  */
uerr_t
retrieve_url (const char *origurl, char **file, char **newloc,
	      const char *refurl, int *dt)
{
  uerr_t result;
  char *url;
  int location_changed, dummy;
  int use_proxy;
  char *mynewloc, *proxy;
  struct url *u;
  int up_error_code;		/* url parse error code */
  char *local_file;
  struct hash_table *redirections = NULL;

  /* If dt is NULL, just ignore it.  */
  if (!dt)
    dt = &dummy;
  url = xstrdup (origurl);
  if (newloc)
    *newloc = NULL;
  if (file)
    *file = NULL;

  u = url_parse (url, &up_error_code);
  if (!u)
    {
      logprintf (LOG_NOTQUIET, "%s: %s.\n", url, url_error (up_error_code));
      if (redirections)
	string_set_free (redirections);
      xfree (url);
      return URLERROR;
    }

  if (!refurl)
    refurl = opt.referer;

 redirected:

  result = NOCONERROR;
  mynewloc = NULL;
  local_file = NULL;

  use_proxy = USE_PROXY_P (u);
  if (use_proxy)
    {
      struct url *proxy_url;

      /* Get the proxy server for the current scheme.  */
      proxy = getproxy (u->scheme);
      if (!proxy)
	{
	  logputs (LOG_NOTQUIET, _("Could not find proxy host.\n"));
	  url_free (u);
	  if (redirections)
	    string_set_free (redirections);
	  xfree (url);
	  return PROXERR;
	}

      /* Parse the proxy URL.  */
      proxy_url = url_parse (proxy, &up_error_code);
      if (!proxy_url)
	{
	  logprintf (LOG_NOTQUIET, _("Error parsing proxy URL %s: %s.\n"),
		     proxy, url_error (up_error_code));
	  if (redirections)
	    string_set_free (redirections);
	  xfree (url);
	  return PROXERR;
	}
      if (proxy_url->scheme != SCHEME_HTTP)
	{
	  logprintf (LOG_NOTQUIET, _("Error in proxy URL %s: Must be HTTP.\n"), proxy);
	  url_free (proxy_url);
	  if (redirections)
	    string_set_free (redirections);
	  xfree (url);
	  return PROXERR;
	}

      result = http_loop (u, &mynewloc, &local_file, refurl, dt, proxy_url);
      url_free (proxy_url);
    }
  else if (u->scheme == SCHEME_HTTP
#ifdef HAVE_SSL
      || u->scheme == SCHEME_HTTPS
#endif
      )
    {
      result = http_loop (u, &mynewloc, &local_file, refurl, dt, NULL);
    }
  else if (u->scheme == SCHEME_FTP)
    {
      /* If this is a redirection, we must not allow recursive FTP
	 retrieval, so we save recursion to oldrec, and restore it
	 later.  */
      int oldrec = opt.recursive;
      if (redirections)
	opt.recursive = 0;
      result = ftp_loop (u, dt);
      opt.recursive = oldrec;
#if 0
      /* There is a possibility of having HTTP being redirected to
	 FTP.  In these cases we must decide whether the text is HTML
	 according to the suffix.  The HTML suffixes are `.html' and
	 `.htm', case-insensitive.  */
      if (redirections && u->local && (u->scheme == SCHEME_FTP))
	{
	  char *suf = suffix (u->local);
	  if (suf && (!strcasecmp (suf, "html") || !strcasecmp (suf, "htm")))
	    *dt |= TEXTHTML;
	}
#endif
    }
  location_changed = (result == NEWLOCATION);
  if (location_changed)
    {
      char *construced_newloc;
      struct url *newloc_parsed;

      assert (mynewloc != NULL);

      if (local_file)
	xfree (local_file);

      /* The HTTP specs only allow absolute URLs to appear in
	 redirects, but a ton of boneheaded webservers and CGIs out
	 there break the rules and use relative URLs, and popular
	 browsers are lenient about this, so wget should be too. */
      construced_newloc = uri_merge (url, mynewloc);
      xfree (mynewloc);
      mynewloc = construced_newloc;

      /* Now, see if this new location makes sense. */
      newloc_parsed = url_parse (mynewloc, &up_error_code);
      if (!newloc_parsed)
	{
	  logprintf (LOG_NOTQUIET, "%s: %s.\n", mynewloc,
		     url_error (up_error_code));
	  url_free (u);
	  if (redirections)
	    string_set_free (redirections);
	  xfree (url);
	  xfree (mynewloc);
	  return result;
	}

      /* Now mynewloc will become newloc_parsed->url, because if the
         Location contained relative paths like .././something, we
         don't want that propagating as url.  */
      xfree (mynewloc);
      mynewloc = xstrdup (newloc_parsed->url);

      if (!redirections)
	{
	  redirections = make_string_hash_table (0);
	  /* Add current URL immediately so we can detect it as soon
             as possible in case of a cycle. */
	  string_set_add (redirections, u->url);
	}

      /* The new location is OK.  Check for redirection cycle by
         peeking through the history of redirections. */
      if (string_set_contains (redirections, newloc_parsed->url))
	{
	  logprintf (LOG_NOTQUIET, _("%s: Redirection cycle detected.\n"),
		     mynewloc);
	  url_free (newloc_parsed);
	  url_free (u);
	  if (redirections)
	    string_set_free (redirections);
	  xfree (url);
	  xfree (mynewloc);
	  return WRONGCODE;
	}
      string_set_add (redirections, newloc_parsed->url);

      xfree (url);
      url = mynewloc;
      url_free (u);
      u = newloc_parsed;
      goto redirected;
    }

  if (local_file)
    {
      if (*dt & RETROKF)
	{
	  register_download (url, local_file);
	  if (redirections)
	    register_all_redirections (redirections, url);
	  if (*dt & TEXTHTML)
	    register_html (url, local_file);
	}
    }

  if (file)
    *file = local_file ? local_file : NULL;
  else
    FREE_MAYBE (local_file);

  url_free (u);
  if (redirections)
    string_set_free (redirections);

  if (newloc)
    *newloc = url;
  else
    xfree (url);

  ++global_download_count;

  return result;
}

/* Find the URLs in the file and call retrieve_url() for each of
   them.  If HTML is non-zero, treat the file as HTML, and construct
   the URLs accordingly.

   If opt.recursive is set, call recursive_retrieve() for each file.  */
uerr_t
retrieve_from_file (const char *file, int html, int *count)
{
  uerr_t status;
  struct urlpos *url_list, *cur_url;

  url_list = (html ? get_urls_html (file, NULL, FALSE, NULL)
	      : get_urls_file (file));
  status = RETROK;             /* Suppose everything is OK.  */
  *count = 0;                  /* Reset the URL count.  */

  for (cur_url = url_list; cur_url; cur_url = cur_url->next, ++*count)
    {
      char *filename = NULL, *new_file;
      int dt;

      if (cur_url->ignore_when_downloading)
	continue;

      if (downloaded_exceeds_quota ())
	{
	  status = QUOTEXC;
	  break;
	}
      if (opt.recursive && cur_url->url->scheme != SCHEME_FTP)
	status = retrieve_tree (cur_url->url->url);
      else
	status = retrieve_url (cur_url->url->url, &filename, &new_file, NULL, &dt);

      if (filename && opt.delete_after && file_exists_p (filename))
	{
	  DEBUGP (("Removing file due to --delete-after in"
		   " retrieve_from_file():\n"));
	  logprintf (LOG_VERBOSE, _("Removing %s.\n"), filename);
	  if (unlink (filename))
	    logprintf (LOG_NOTQUIET, "unlink: %s\n", strerror (errno));
	  dt &= ~RETROKF;
	}

      FREE_MAYBE (new_file);
      FREE_MAYBE (filename);
    }

  /* Free the linked list of URL-s.  */
  free_urlpos (url_list);

  return status;
}

/* Print `giving up', or `retrying', depending on the impending
   action.  N1 and N2 are the attempt number and the attempt limit.  */
void
printwhat (int n1, int n2)
{
  logputs (LOG_VERBOSE, (n1 == n2) ? _("Giving up.\n\n") : _("Retrying.\n\n"));
}

/* Increment opt.downloaded by BY_HOW_MUCH.  If an overflow occurs,
   set opt.downloaded_overflow to 1. */
void
downloaded_increase (unsigned long by_how_much)
{
  VERY_LONG_TYPE old;
  if (opt.downloaded_overflow)
    return;
  old = opt.downloaded;
  opt.downloaded += by_how_much;
  if (opt.downloaded < old)	/* carry flag, where are you when I
                                   need you? */
    {
      /* Overflow. */
      opt.downloaded_overflow = 1;
      opt.downloaded = ~((VERY_LONG_TYPE)0);
    }
}

/* Return non-zero if the downloaded amount of bytes exceeds the
   desired quota.  If quota is not set or if the amount overflowed, 0
   is returned. */
int
downloaded_exceeds_quota (void)
{
  if (!opt.quota)
    return 0;
  if (opt.downloaded_overflow)
    /* We don't really know.  (Wildly) assume not. */
    return 0;

  return opt.downloaded > opt.quota;
}

/* If opt.wait or opt.waitretry are specified, and if certain
   conditions are met, sleep the appropriate number of seconds.  See
   the documentation of --wait and --waitretry for more information.

   COUNT is the count of current retrieval, beginning with 1. */

void
sleep_between_retrievals (int count)
{
  static int first_retrieval = 1;

  if (!first_retrieval && (opt.wait || opt.waitretry))
    {
      if (opt.waitretry && count > 1)
	{
	  /* If opt.waitretry is specified and this is a retry, wait
	     for COUNT-1 number of seconds, or for opt.waitretry
	     seconds.  */
	  if (count <= opt.waitretry)
	    sleep (count - 1);
	  else
	    sleep (opt.waitretry);
	}
      else if (opt.wait)
	{
	  /* Otherwise, check if opt.wait is specified.  If so, sleep.  */
	  if (count > 1 || !opt.random_wait)
	    sleep (opt.wait);
	  else
	    {
	      int waitsecs = random() % (opt.wait * 2 + 1);
	      DEBUGP(("sleep_between_retrievals: norm=%ld,random=%ld,sleep=%d\n",
		      opt.wait, waitsecs - opt.wait, waitsecs));
	      sleep(waitsecs);
	    }
	}
    }
  if (first_retrieval)
    first_retrieval = 0;
}