[svn] Fix downloading of duplicate URLs.

Published in <sxsvgfmu2bj.fsf@florida.arsdigita.de>.

src/ChangeLog

@@ -1,3 +1,22 @@
+2001-12-04  Hrvoje Niksic  <hniksic@arsdigita.com>
+
+	* recur.c (retrieve_tree): Check whether the URL was already
+	downloaded before downloading it again.
+	(descend_child_p): Renamed to download_child_p.
+	(register_download): When one URL is downloaded to a file already
+	"owned" by another URL, delete all references that map any URL to
+	that file.
+	(register_delete_file): New function.
+	(retrieve_tree): Use it after deleting a file.
+
+	* url.c (url_parse): Re-canonicalize the URL also if the path is
+	empty, so that e.g. "http://www.server.com" ->
+	"http://www.server.com/".
+	(lowercase_str): Use ISUPPER instead of !ISLOWER.
+
+	* retr.c (retrieve_url): Use the canonical URL form when calling
+	register_download().
+
 2001-12-04  Ian Abbott <abbotti@mev.co.uk>
 
 	* snprintf.c (dopr): Use `unsigned int' as the second argument to

src/recur.c

@@ -58,6 +58,8 @@ static struct hash_table *dl_url_file_map;
    in order.  If you need to check whether a file has been downloaded,
    use a hash table, e.g. dl_file_url_map.  */
 static slist *downloaded_html_files;
+
+static void register_delete_file PARAMS ((const char *));
 
 /* Functions for maintaining the URL queue.  */
 
@@ -150,7 +152,7 @@ url_dequeue (struct url_queue *queue,
   return 1;
 }
 
-static int descend_url_p PARAMS ((const struct urlpos *, struct url *, int,
+static int download_child_p PARAMS ((const struct urlpos *, struct url *, int,
 				     struct url *, struct hash_table *));
 static int descend_redirect_p PARAMS ((const char *, const char *, int,
 				       struct url *, struct hash_table *));
@@ -205,19 +207,30 @@ retrieve_tree (const char *start_url)
 
       if (downloaded_exceeds_quota ())
 	break;
-
       if (status == FWRITEERR)
 	break;
 
-      /* Get the next URL from the queue. */
+      /* Get the next URL from the queue... */
 
       if (!url_dequeue (queue,
 			(const char **)&url, (const char **)&referer,
 			&depth))
 	break;
 
-      /* And download it. */
+      /* ...and download it.  Note that this download is in most cases
-
+	 unconditional, as download_child_p already makes sure a file
+	 doesn't get enqueued twice -- and yet this check is here, and
+	 not in download_child_p.  This is so that if you run `wget -r
+	 URL1 URL2', and a random URL is encountered once under URL1
+	 and again under URL2, but at a different (possibly smaller)
+	 depth, we want the URL's children to be taken into account
+	 the second time.  */
+      if (dl_url_file_map && hash_table_contains (dl_url_file_map, url))
+	{
+	  DEBUGP (("Already downloaded \"%s\", reusing it from \"%s\".\n",
+		   url, (char *)hash_table_get (dl_url_file_map, url)));
+	}
+      else
 	{
 	  int dt = 0;
 	  char *redirected = NULL;
@@ -305,7 +318,7 @@ retrieve_tree (const char *start_url)
 		    continue;
 		  if (dash_p_leaf_HTML && !child->link_inline_p)
 		    continue;
-		  if (descend_url_p (child, url_parsed, depth, start_url_parsed,
+		  if (download_child_p (child, url_parsed, depth, start_url_parsed,
 					blacklist))
 		    {
 		      url_enqueue (queue, xstrdup (child->url->url),
@@ -338,6 +351,7 @@ retrieve_tree (const char *start_url)
 		     file);
 	  if (unlink (file))
 	    logprintf (LOG_NOTQUIET, "unlink: %s\n", strerror (errno));
+	  register_delete_file (file);
 	}
 
       xfree (url);
@@ -379,7 +393,7 @@ retrieve_tree (const char *start_url)
    will help if those URLs are encountered many times.  */
 
 static int
-descend_url_p (const struct urlpos *upos, struct url *parent, int depth,
+download_child_p (const struct urlpos *upos, struct url *parent, int depth,
 		  struct url *start_url_parsed, struct hash_table *blacklist)
 {
   struct url *u = upos->url;
@@ -555,10 +569,10 @@ descend_url_p (const struct urlpos *upos, struct url *parent, int depth,
   return 0;
 }
 
-/* This function determines whether we should descend the children of
+/* This function determines whether we will consider downloading the
-   the URL whose download resulted in a redirection, possibly to
+   children of a URL whose download resulted in a redirection,
-   another host, etc.  It is needed very rarely, and thus it is merely
+   possibly to another host, etc.  It is needed very rarely, and thus
-   a simple-minded wrapper around descend_url_p.  */
+   it is merely a simple-minded wrapper around download_child_p.  */
 
 static int
 descend_redirect_p (const char *redirected, const char *original, int depth,
@@ -578,7 +592,7 @@ descend_redirect_p (const char *redirected, const char *original, int depth,
   memset (upos, 0, sizeof (*upos));
   upos->url = new_parsed;
 
-  success = descend_url_p (upos, orig_parsed, depth,
+  success = download_child_p (upos, orig_parsed, depth,
 			      start_url_parsed, blacklist);
 
   url_free (orig_parsed);
@@ -592,21 +606,94 @@ descend_redirect_p (const char *redirected, const char *original, int depth,
 }
 
 
-/* Register that URL has been successfully downloaded to FILE. */
+#define ENSURE_TABLES_EXIST do {			\
+  if (!dl_file_url_map)					\
+    dl_file_url_map = make_string_hash_table (0);	\
+  if (!dl_url_file_map)					\
+    dl_url_file_map = make_string_hash_table (0);	\
+} while (0)
+
+static int
+dissociate_urls_from_file_mapper (void *key, void *value, void *arg)
+{
+  char *mapping_url = (char *)key;
+  char *mapping_file = (char *)value;
+  char *file = (char *)arg;
+
+  if (0 == strcmp (mapping_file, file))
+    {
+      hash_table_remove (dl_url_file_map, mapping_url);
+      xfree (mapping_url);
+      xfree (mapping_file);
+    }
+
+  /* Continue mapping. */
+  return 0;
+}
+
+/* Remove all associations from various URLs to FILE from dl_url_file_map. */
+
+static void
+dissociate_urls_from_file (const char *file)
+{
+  hash_table_map (dl_url_file_map, dissociate_urls_from_file_mapper,
+		  (char *)file);
+}
+
+/* Register that URL has been successfully downloaded to FILE.  This
+   is used by the link conversion code to convert references to URLs
+   to references to local files.  It is also being used to check if a
+   URL has already been downloaded.  */
 
 void
 register_download (const char *url, const char *file)
 {
-  if (!opt.convert_links)
+  char *old_file, *old_url;
-    return;
+
-  if (!dl_file_url_map)
+  ENSURE_TABLES_EXIST;
-    dl_file_url_map = make_string_hash_table (0);
+
-  if (!dl_url_file_map)
+  /* With some forms of retrieval, it is possible, although not
-    dl_url_file_map = make_string_hash_table (0);
+     likely, for different URLs to resolve to the same file name.  For
+     example, "http://www.server.com/" and
+     "http://www.server.com/index.html" will both resolve to the same
+     file, "index.html".  If both are downloaded, the second download
+     will override the first one.
+
+     If that happens, dissociate the old file name from the URL.  */
+
+  if (hash_table_get_pair (dl_file_url_map, file, &old_file, &old_url))
+    {
+      if (0 == strcmp (url, old_url))
+	/* We have somehow managed to download the same URL twice.
+	   Nothing to do.  */
+	return;
+
+      hash_table_remove (dl_file_url_map, file);
+      xfree (old_file);
+      xfree (old_url);
+
+      /* Remove all the URLs that point to this file.  Yes, there can
+	 be more than one such URL, because we store redirections as
+	 multiple entries in dl_url_file_map.  For example, if URL1
+	 redirects to URL2 which gets downloaded to FILE, we map both
+	 URL1 and URL2 to FILE in dl_url_file_map.  (dl_file_url_map
+	 only points to URL2.)  When another URL gets loaded to FILE,
+	 we want both URL1 and URL2 dissociated from it.
+
+         This is a relatively expensive operation because it performs
+         a linear search of the whole hash table, but it should be
+         called very rarely, only when two URLs resolve to the same
+         file name, *and* the "<file>.1" extensions are turned off.
+         In other words, almost never.  */
+      dissociate_urls_from_file (file);
+    }
+
+  /* A URL->FILE mapping is not possible without a FILE->URL mapping.
+     If the latter were present, it should have been removed by the
+     above `if'.  */
+  assert (!hash_table_contains (dl_url_file_map, url));
 
-  if (!hash_table_contains (dl_file_url_map, file))
   hash_table_put (dl_file_url_map, xstrdup (file), xstrdup (url));
-  if (!hash_table_contains (dl_url_file_map, url))
   hash_table_put (dl_url_file_map, xstrdup (url), xstrdup (file));
 }
 
@@ -619,8 +706,7 @@ register_redirection (const char *from, const char *to)
 {
   char *file;
 
-  if (!opt.convert_links)
+  ENSURE_TABLES_EXIST;
-    return;
 
   file = hash_table_get (dl_url_file_map, to);
   assert (file != NULL);
@@ -628,7 +714,25 @@ register_redirection (const char *from, const char *to)
     hash_table_put (dl_url_file_map, xstrdup (from), xstrdup (file));
 }
 
-/* Register that URL corresponds to the HTML file FILE. */
+/* Register that the file has been deleted. */
+
+static void
+register_delete_file (const char *file)
+{
+  char *old_url, *old_file;
+
+  ENSURE_TABLES_EXIST;
+
+  if (!hash_table_get_pair (dl_file_url_map, file, &old_file, &old_url))
+    return;
+
+  hash_table_remove (dl_file_url_map, file);
+  xfree (old_file);
+  xfree (old_url);
+  dissociate_urls_from_file (file);
+}
+
+/* Register that FILE is an HTML file that has been downloaded. */
 
 void
 register_html (const char *url, const char *file)
@@ -672,15 +776,16 @@ convert_all_links (void)
       struct urlpos *urls, *cur_url;
       char *url;
 
-      DEBUGP (("Rescanning %s\n", html->string));
-
       /* Determine the URL of the HTML file.  get_urls_html will need
 	 it.  */
       url = hash_table_get (dl_file_url_map, html->string);
-      if (url)
+      if (!url)
-	DEBUGP (("It should correspond to %s.\n", url));
+	{
-      else
+	  DEBUGP (("Apparently %s has been removed.\n", html->string));
-	DEBUGP (("I cannot find the corresponding URL.\n"));
+	  continue;
+	}
+
+      DEBUGP (("Rescanning %s (from %s)\n", html->string, url));
 
       /* Parse the HTML file...  */
       urls = get_urls_html (html->string, url, NULL);

src/retr.c

@@ -511,11 +511,11 @@ retrieve_url (const char *origurl, char **file, char **newloc,
     {
       if (*dt & RETROKF)
 	{
-	  register_download (url, local_file);
+	  register_download (u->url, local_file);
 	  if (redirections)
-	    register_all_redirections (redirections, url);
+	    register_all_redirections (redirections, u->url);
 	  if (*dt & TEXTHTML)
-	    register_html (url, local_file);
+	    register_html (u->url, local_file);
 	}
     }
 

src/url.c

@@ -595,7 +595,7 @@ lowercase_str (char *str)
 {
   int change = 0;
   for (; *str; str++)
-    if (!ISLOWER (*str))
+    if (ISUPPER (*str))
       {
 	change = 1;
 	*str = TOLOWER (*str);
@@ -787,13 +787,11 @@ url_parse (const char *url, int *error)
   if (fragment_b)
     u->fragment = strdupdelim (fragment_b, fragment_e);
 
-
+  if (path_modified || u->fragment || host_modified || path_b == path_e)
-  if (path_modified || u->fragment || host_modified)
     {
-      /* If path_simplify modified the path, or if a fragment is
+      /* If we suspect that a transformation has rendered what
-	 present, or if the original host name had caps in it, make
+	 url_string might return different from URL_ENCODED, rebuild
-	 sure that u->url is equivalent to what would be printed by
+	 u->url using url_string.  */
-	 url_string.  */
       u->url = url_string (u, 0);
 
       if (url_encoded != url)