bug#51712: 29.0.50; [PATCH] New function `xwidget-webkit-load-html'

[Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

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Eli Zaretskii <eliz@gnu.org> writes:

> Then I'd suggest not to have it defined on non-GTK builds for now.  It
> is confusing to have a function that silently does nothing (after
> wasting some cycles).

Thanks, I'll keep that in mind.

> I'd say that TEXT should be a string.  The name itself doesn't
> necessarily say so.

Fixed, thanks.
>> +Optional argument @var{base-uri}, which should be a string, specifies
>> +the location of web resources, such as the resource @samp{foo.png} in
>> +the HTML tag @samp{<img src="foo.png">}.  It defaults to
>> +@samp{about:blank}.

> Hmm... this is better, but at least I am still in the dark regarding
> the need for this optional argument.  E.g., what would happen if you
> use that tag, but don't specify the URI?

I'm in the dark too.  I am not a web developer, and browser engines are
remarkably lax about these things, but hopefully Lars can explain better
(after all, shr must deal with these things too), so I added him to the
Ccs.

> This still leaves me wondering why the entry talks about temporary
> files.

Previously, loading custom markup into a widget required using a
temporary file to store the markup.

>> +DEFUN ("xwidget-webkit-load-html", Fxwidget_webkit_load_html,
>> +       Sxwidget_webkit_load_html, 2, 3, 0,
>> +       doc: /* Make XWIDGET's WebKit widget render text.
>                                                       ^^^^
> "text" should be in CAPS.

Thanks.

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From 8877c57a09dce06f6b1b64294ce8a632f862cc6e Mon Sep 17 00:00:00 2001
From: Po Lu <luangruo@yahoo.com>
Date: Tue, 9 Nov 2021 21:36:40 +0800
Subject: [PATCH] Add `xwidget-webkit-load-html'

* doc/lispref/display.texi (Xwidgets): Document new function.
* etc/NEWS: Announce new function.
* src/xwidget.c (Fxwidget_webkit_load_html): New function.
(syms_of_xwidget): Define new subr.
---
 doc/lispref/display.texi | 11 +++++++++++
 etc/NEWS                 |  5 +++++
 src/xwidget.c            | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+)

diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index b6bd14f887..0b6dc05267 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -6943,6 +6943,17 @@ Xwidgets
 signals an error.
 @end defun
 
+@defun xwidget-webkit-load-html xwidget text &optional base-uri
+Load @var{text}, a string, into @var{xwidget}, which should be a
+WebKit xwidget.  It treats @var{text} as HTML markup, which will be
+rendered by @var{xwidget}.
+
+Optional argument @var{base-uri}, which should be a string, specifies
+the location of web resources, such as the resource @samp{foo.png} in
+the HTML tag @samp{<img src="foo.png">}.  It defaults to
+@samp{about:blank}.
+@end defun
+
 @node Buttons
 @section Buttons
 @cindex buttons in buffers
diff --git a/etc/NEWS b/etc/NEWS
index 807f31fa33..b55630336e 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -792,6 +792,11 @@ what the widget will actually receive.
 
 On GTK+, only key and function key events are implemented.
 
++++
+*** New function 'xwidget-webkit-load-html'.
+This function is used to load HTML text into WebKit xwidgets, without
+having to create a temporary file to store the markup.
+
 +++
 *** New functions for performing searches on WebKit xwidgets.
 Some new functions, such as 'xwidget-webkit-search', have been added
diff --git a/src/xwidget.c b/src/xwidget.c
index fc76ce307e..2587b658e7 100644
--- a/src/xwidget.c
+++ b/src/xwidget.c
@@ -2139,6 +2139,43 @@ DEFUN ("xwidget-webkit-finish-search", Fxwidget_webkit_finish_search,
   return Qnil;
 }
 
+#ifdef USE_GTK
+DEFUN ("xwidget-webkit-load-html", Fxwidget_webkit_load_html,
+       Sxwidget_webkit_load_html, 2, 3, 0,
+       doc: /* Make XWIDGET's WebKit widget render TEXT.
+XWIDGET should be a WebKit xwidget, that will receive TEXT.  TEXT
+should be a string that will be displayed by XWIDGET as HTML markup.
+BASE_URI should be a string containing a URI that is used to fetch
+resources, and if not specified, defaults to `about:blank'.  */)
+  (Lisp_Object xwidget, Lisp_Object text, Lisp_Object base_uri)
+{
+  struct xwidget *xw;
+  WebKitWebView *webview;
+  char *data, *uri;
+
+  CHECK_XWIDGET (xwidget);
+  CHECK_STRING (text);
+  if (NILP (base_uri))
+    base_uri = build_string ("about:blank");
+  else
+    CHECK_STRING (base_uri);
+
+  base_uri = ENCODE_UTF_8 (base_uri);
+  text = ENCODE_UTF_8 (text);
+  xw = XXWIDGET (xwidget);
+
+  data = SSDATA (text);
+  uri = SSDATA (base_uri);
+  webview = WEBKIT_WEB_VIEW (xw->widget_osr);
+
+  block_input ();
+  webkit_web_view_load_html (webview, data, uri);
+  unblock_input ();
+
+  return Qnil;
+}
+#endif
+
 void
 syms_of_xwidget (void)
 {
@@ -2177,6 +2214,9 @@ syms_of_xwidget (void)
   defsubr (&Sxwidget_webkit_next_result);
   defsubr (&Sxwidget_webkit_previous_result);
   defsubr (&Sset_xwidget_buffer);
+#ifdef USE_GTK
+  defsubr (&Sxwidget_webkit_load_html);
+#endif
 
   DEFSYM (QCxwidget, ":xwidget");
   DEFSYM (QCtitle, ":title");
-- 
2.31.1