[PATCH] Support for <meta charset=...> tag

[Sho Amano]

Hi! I've been using the first version of wget for a long time and first of all,
I want to say thank you to all of the maintainers and contributors of
this project!

I was looking at the code recently to find that it doesn't support
"<meta charset=...>" tag yet.
I don't see any issues in bug tracker related to this, so I created a patch.
I'm hoping it helps.


I also provide sample HTML files to verify.
https://www.dropbox.com/s/zgicd05jdppq781/charset_test_utf_8.html?dl=0
https://www.dropbox.com/s/001pklu3itad6sw/charset_test_shift_jis.html?dl=0

The first file specifies a Japanese file name in UTF-8. The second file does
in Shift-JIS. Save these files, serve them on localhost:8080, and let wget
follow the link. (e.g. `wget -d --recursive --level=2
http://localhost:8080/charset_test_shift_jis.html`)
Verify that in both cases, wget tries to download
http://localhost:8080/%E6%97%A5%E6%9C%AC%E8%AA%9E.html.

Thanks!
Sho Amano

---
 src/html-url.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/html-url.c b/src/html-url.c
index b80cf269..5324d244 100644
--- a/src/html-url.c
+++ b/src/html-url.c
@@ -182,6 +182,7 @@ static const char *additional_attributes[] = {
   "http-equiv",                 /* used by tag_handle_meta  */
   "name",                       /* used by tag_handle_meta  */
   "content",                    /* used by tag_handle_meta  */
+  "charset",                    /* used by tag_handle_meta  */
   "action",                     /* used by tag_handle_form  */
   "style",                      /* used by check_style_attr */
   "srcset",                     /* used by tag_handle_img */
@@ -191,7 +192,7 @@ static struct hash_table *interesting_tags;
 static struct hash_table *interesting_attributes;

 /* Will contains the (last) charset found in 'http-equiv=content-type'
-   meta tags  */
+   or 'charset' meta tags  */
 static char *meta_charset;

 static void
@@ -574,6 +575,7 @@ tag_handle_meta (int tagid _GL_UNUSED, struct
taginfo *tag, struct map_context *
 {
   char *name = find_attr (tag, "name", NULL);
   char *http_equiv = find_attr (tag, "http-equiv", NULL);
+  char *charset = find_attr (tag, "charset", NULL);

   if (http_equiv && 0 == c_strcasecmp (http_equiv, "refresh"))
     {
@@ -673,6 +675,20 @@ tag_handle_meta (int tagid _GL_UNUSED, struct
taginfo *tag, struct map_context *
             }
         }
     }
+  else if (charset)
+    {
+      /* Handle stuff like:
+         <meta charset="CHARSET">
+         If charset is acquired from http-equiv then it is overwritten. */
+
+      /* Do a minimum check on the charset value */
+      if (check_encoding_name (charset))
+        {
+          char *mcharset = xstrdup (charset);
+          xfree (meta_charset);
+          meta_charset = mcharset;
+        }
+    }
 }

 /* Handle the IMG tag.  This requires special handling for the srcset attr,
-- 
2.17.1