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Re: What's the right way to detect libxml2?
From: |
Robert Pluim |
Subject: |
Re: What's the right way to detect libxml2? |
Date: |
Wed, 25 Oct 2017 13:24:34 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.0.90 (gnu/linux) |
Andy Moreton <address@hidden> writes:
> On Tue 24 Oct 2017, Robert Pluim wrote:
>> Like thus? Very lightly tested on GNU/Linux only. Might need a NEWS
>> entry.
>>
> Works for me on a 64bit MinGW64/MSYS2 build of emacs-26 on Windows 10.
OK.
> I don't think you need to remove the HAVE_LIBXML2 conditionals, as lisp
> code can check (fboundp 'libxml-available-p) before calling it, and it
> may break builds without libxml2 support.
I'm following the gnutls model, where gnutls-available-p is always
available, so you don't have to do
(and (fboundp 'libxml-available-p) (libxml-available-p))
If a build without libxml2 support breaks, then we fix the code in
emacs. Actually, my patch breaks --without-xml2 :-)
> Also, the libxml-available-p doc string claims it returns a list of
> capabilities (which is true for gnutls-available-p), but it only returns
> nil or t.
Ah yes, too much cut & paste. Revised version attached. Compile and
run-tested with and without xml2 on GNU/Linux.
>From 10fe04edc5adf942c2bf9806eea5dd81edd2c9a5 Mon Sep 17 00:00:00 2001
From: Robert Pluim <address@hidden>
Date: Tue, 24 Oct 2017 19:01:28 +0200
Subject: [PATCH] Provide libxml-available-p
* src/emacs.c (main): Call syms_of_xml unconditionally
* src/lisp.h: Provide syms_of_xml prototype even when
HAVE_LIBXML2 is not defined
* src/xml.c (Flibxml_available_p): New function, cloned from
Fgnutls_available_p
(syms_of_xml): Provide Slibxml_available_p
* doc/lispref/text.texi (Parsing HTML/XML): Document libxml-available-p
---
doc/lispref/text.texi | 5 +++++
src/emacs.c | 2 --
src/lisp.h | 2 +-
src/xml.c | 37 ++++++++++++++++++++++++++++++++-----
4 files changed, 38 insertions(+), 8 deletions(-)
diff --git a/doc/lispref/text.texi b/doc/lispref/text.texi
index baa3c708e9..565d098069 100644
--- a/doc/lispref/text.texi
+++ b/doc/lispref/text.texi
@@ -4723,6 +4723,11 @@ Parsing HTML/XML
@section Parsing HTML and XML
@cindex parsing html
address@hidden libxml-available-p
+This function returns address@hidden if built-in libxml2 support is
+available.
address@hidden defun
+
When Emacs is compiled with libxml2 support, the following functions
are available to parse HTML or XML text into Lisp object trees.
diff --git a/src/emacs.c b/src/emacs.c
index 0fe7d9113b..808abcd9aa 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -1542,9 +1542,7 @@ Using an Emacs configured with --with-x-toolkit=lucid
does not have this problem
#endif
#endif /* HAVE_X_WINDOWS */
-#ifdef HAVE_LIBXML2
syms_of_xml ();
-#endif
#ifdef HAVE_LCMS2
syms_of_lcms2 ();
diff --git a/src/lisp.h b/src/lisp.h
index 266370333f..cc8d90cbf1 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -4399,9 +4399,9 @@ extern void syms_of_xterm (void);
extern char *x_get_keysym_name (int);
#endif /* HAVE_WINDOW_SYSTEM */
-#ifdef HAVE_LIBXML2
/* Defined in xml.c. */
extern void syms_of_xml (void);
+#ifdef HAVE_LIBXML2
extern void xml_cleanup_parser (void);
#endif
diff --git a/src/xml.c b/src/xml.c
index d087a34a5e..7afaa63c42 100644
--- a/src/xml.c
+++ b/src/xml.c
@@ -18,15 +18,15 @@ along with GNU Emacs. If not, see
<https://www.gnu.org/licenses/>. */
#include <config.h>
+#include "lisp.h"
+#include "buffer.h"
+
#ifdef HAVE_LIBXML2
#include <libxml/tree.h>
#include <libxml/parser.h>
#include <libxml/HTMLparser.h>
-#include "lisp.h"
-#include "buffer.h"
-
#ifdef WINDOWSNT
@@ -291,16 +291,43 @@ If DISCARD-COMMENTS is non-nil, all HTML comments are
discarded. */)
return parse_region (start, end, base_url, discard_comments, false);
return Qnil;
}
+#endif /* HAVE_LIBXML2 */
+
+DEFUN ("libxml-available-p", Flibxml_available_p, Slibxml_available_p, 0, 0, 0,
+ doc: /* Return t if libxml2 support is available in this instance of
Emacs.*/)
+ (void)
+{
+#ifdef HAVE_LIBXML2
+# ifdef WINDOWSNT
+ Lisp_Object found = Fassq (Qlibxml2, Vlibrary_cache);
+ if (CONSP (found))
+ return XCDR (found);
+ else
+ {
+ Lisp_Object status;
+ status = init_libxml2_functions () ? Qt : Qnil;
+ Vlibrary_cache = Fcons (Fcons (Qlibxml2, status), Vlibrary_cache);
+ return status;
+ }
+# else
+ return Qt;
+# endif /* WINDOWSNT */
+#else
+ return Qnil;
+#endif /* HAVE_LIBXML2 */
+}
+
/***********************************************************************
Initialization
***********************************************************************/
void
syms_of_xml (void)
{
+#ifdef HAVE_LIBXML2
defsubr (&Slibxml_parse_html_region);
defsubr (&Slibxml_parse_xml_region);
+#endif
+ defsubr (&Slibxml_available_p);
}
-
-#endif /* HAVE_LIBXML2 */
--
2.15.0.rc1
- What's the right way to detect libxml2?, Clément Pit-Claudel, 2017/10/22
- Re: What's the right way to detect libxml2?, Phillip Lord, 2017/10/22
- Re: What's the right way to detect libxml2?, Andy Moreton, 2017/10/24
- Re: What's the right way to detect libxml2?, Clément Pit-Claudel, 2017/10/24
- Re: What's the right way to detect libxml2?, Andy Moreton, 2017/10/24
- Re: What's the right way to detect libxml2?, Robert Pluim, 2017/10/24
- Re: What's the right way to detect libxml2?, Andy Moreton, 2017/10/24
- Re: What's the right way to detect libxml2?,
Robert Pluim <=
- Re: What's the right way to detect libxml2?, Eli Zaretskii, 2017/10/28
- Re: What's the right way to detect libxml2?, Robert Pluim, 2017/10/30
- Re: What's the right way to detect libxml2?, Eli Zaretskii, 2017/10/30
- Re: What's the right way to detect libxml2?, Eli Zaretskii, 2017/10/30
- Re: What's the right way to detect libxml2?, Richard Stallman, 2017/10/24
- Re: What's the right way to detect libxml2?, John Wiegley, 2017/10/24
- Re: What's the right way to detect libxml2?, Stefan Monnier, 2017/10/24
- Re: What's the right way to detect libxml2?, Paul Eggert, 2017/10/25
- Re: What's the right way to detect libxml2?, Richard Stallman, 2017/10/25
- Re: What's the right way to detect libxml2?, Werner LEMBERG, 2017/10/25