Make the fetching of a contents encoding generic.

The frontends previously had to use an html renderer API to get the
encoding of a content. This also required the explicit checking of the
contents type rather than using the existing content API to abstract
this knowledge.

content/content.c

@@ -1301,6 +1301,30 @@ bool content_get_quirks(hlcache_handle *h)
 }
 
 
+/**
+ * Retrieve the encoding of a content
+ *
+ * \param c  Content to retrieve bitmap from
+ * \return Pointer to bitmap, or NULL if none.
+ */
+const char *content_get_encoding(hlcache_handle *h)
+{
+	return content__get_encoding(hlcache_handle_get_content(h));
+}
+
+const char *content__get_encoding(struct content *c)
+{
+	const char *encoding = NULL;
+
+	if ((c != NULL) &&
+	    (c->handler != NULL) &&
+	    (c->handler->get_encoding != NULL) ) {
+		encoding = c->handler->get_encoding(c);
+	}
+
+	return encoding;
+}
+
 /**
  * Return whether a content is currently locked
  *

content/content.h

@@ -318,7 +318,8 @@ void content_invalidate_reuse_data(struct hlcache_handle *c);
 nsurl *content_get_refresh_url(struct hlcache_handle *c);
 struct bitmap *content_get_bitmap(struct hlcache_handle *c);
 bool content_get_opaque(struct hlcache_handle *h);
-bool content_get_quirks(struct hlcache_handle *c);
+bool content_get_quirks(struct hlcache_handle *h);
+const char *content_get_encoding(struct hlcache_handle *h);
 
 bool content_is_locked(struct hlcache_handle *h);
 

content/content_protected.h

@@ -79,6 +79,7 @@ struct content_handler {
 	nserror (*debug_dump)(struct content *c, FILE *f, enum content_debug op);
 	nserror (*clone)(const struct content *old, struct content **newc);
 	bool (*matches_quirks)(const struct content *c, bool quirks);
+	const char *(*get_encoding)(const struct content *c);
 	content_type (*type)(void);
 
         /** handler dependant content sensitive internal data interface. */
@@ -196,7 +197,7 @@ void content__invalidate_reuse_data(struct content *c);
 nsurl *content__get_refresh_url(struct content *c);
 struct bitmap *content__get_bitmap(struct content *c);
 bool content__get_opaque(struct content *c);
-
+const char *content__get_encoding(struct content *c);
 bool content__is_locked(struct content *c);
 
 #endif

content/hlcache.c

@@ -718,10 +718,9 @@ nserror hlcache_handle_release(hlcache_handle *handle)
 /* See hlcache.h for documentation */
 struct content *hlcache_handle_get_content(const hlcache_handle *handle)
 {
-	assert(handle != NULL);
-
-	if (handle->entry != NULL)
+	if ((handle != NULL) && (handle->entry != NULL)) {
 		return handle->entry->content;
+	}
 
 	return NULL;
 }

desktop/browser.c

@@ -1907,8 +1907,8 @@ nserror browser_window_navigate(struct browser_window *bw,
 		post.data.urlenc = post_urlenc;
 	}
 
+	child.charset = content_get_encoding(parent);
 	if ((parent != NULL) && (content_get_type(parent) == CONTENT_HTML)) {
-		child.charset = html_get_encoding(parent);
 		child.quirks = content_get_quirks(parent);
 	}
 

gtk/viewsource.c

@@ -23,7 +23,6 @@
 #include "utils/messages.h"
 #include "desktop/browser.h"
 #include "content/content.h"
-#include "render/html.h"
 
 #include "gtk/viewdata.h"
 #include "gtk/viewsource.h"
@@ -62,7 +61,7 @@ void nsgtk_viewsource(GtkWindow *parent, struct browser_window *bw)
 	sprintf(title, "Source of %s - NetSurf", nsurl_access(browser_window_get_url(bw)));
 
 	ret = utf8_from_enc(source_data,
-			  html_get_encoding(hlcontent),
+			  content_get_encoding(hlcontent),
 			  source_size,
 			  &ndata,
 			  &ndata_len);

render/html.c

@@ -2109,16 +2109,16 @@ struct box *html_get_box_tree(hlcache_handle *h)
 /**
  * Retrieve the charset of an HTML document
  *
- * \param h  Content to retrieve charset from
+ * \param c Content to retrieve charset from
  * \return Pointer to charset, or NULL
  */
-const char *html_get_encoding(hlcache_handle *h)
+static const char *html_encoding(const struct content *c)
 {
-	html_content *c = (html_content *) hlcache_handle_get_content(h);
+	html_content *html = (html_content *) c;
 
-	assert(c != NULL);
+	assert(html != NULL);
 
-	return c->encoding;
+	return html->encoding;
 }
 
 /**
@@ -2262,6 +2262,7 @@ static const content_handler html_content_handler = {
 	.search_clear = html_search_clear,
 	.debug_dump = html_debug_dump,
 	.clone = html_clone,
+	.get_encoding = html_encoding,
 	.type = html_content_type,
 	.no_share = true,
 };

render/html.h

@@ -174,7 +174,6 @@ bool text_redraw(const char *utf8_text, size_t utf8_len,
 
 dom_document *html_get_document(struct hlcache_handle *h);
 struct box *html_get_box_tree(struct hlcache_handle *h);
-const char *html_get_encoding(struct hlcache_handle *h);
 dom_hubbub_encoding_source html_get_encoding_source(struct hlcache_handle *h);
 struct content_html_frames *html_get_frameset(struct hlcache_handle *h);
 struct content_html_iframe *html_get_iframe(struct hlcache_handle *h);

riscos/window.c

@@ -3824,11 +3824,11 @@ void ro_gui_window_prepare_pageinfo(struct gui_window *g)
 		sprintf(icon_buf, "file_xxx");
 
 	if (content_get_type(h) == CONTENT_HTML) {
-		if (html_get_encoding(h)) {
+		if (content_get_encoding(h)) {
 			char enc_token[10] = "Encoding0";
 			enc_token[8] = '0' + html_get_encoding_source(h);
 			snprintf(enc_buf, sizeof enc_buf, "%s (%s)",
-					html_get_encoding(h),
+					content_get_encoding(h),
 					messages_get(enc_token));
 			enc = enc_buf;
 		} else {