From 620247ac205b80ceb142ee70500ab2c3ffa46fe2 Mon Sep 17 00:00:00 2001 From: Robert Pluim Date: Fri, 3 Nov 2017 11:33:06 +0200 Subject: [PATCH] New function '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. (GnuTLS Cryptography, Format of GnuTLS Cryptography Inputs) (Document Object Model): Fix indentation of the first paragraph. * etc/NEWS (libxml-available-p): Mention libxml-available-p. --- doc/lispref/text.texi | 25 ++++++++++++++++--------- etc/NEWS | 8 ++++++++ src/emacs.c | 2 -- src/lisp.h | 2 +- src/xml.c | 37 ++++++++++++++++++++++++++++++++----- 5 files changed, 57 insertions(+), 17 deletions(-) diff --git a/doc/lispref/text.texi b/doc/lispref/text.texi index baa3c708e90..6094a41c473 100644 --- a/doc/lispref/text.texi +++ b/doc/lispref/text.texi @@ -4536,9 +4536,9 @@ It should be somewhat more efficient on larger buffers than @cindex symmetric cipher @cindex cipher, symmetric -If compiled with GnuTLS, Emacs offers built-in cryptographic support. -Following the GnuTLS API terminology, the available tools are digests, -MACs, symmetric ciphers, and AEAD ciphers. + If compiled with GnuTLS, Emacs offers built-in cryptographic +support. Following the GnuTLS API terminology, the available tools +are digests, MACs, symmetric ciphers, and AEAD ciphers. The terms used herein, such as IV (Initialization Vector), require some familiarity with cryptography and will not be defined in detail. @@ -4556,7 +4556,7 @@ structure of the GnuTLS library. @cindex format of gnutls cryptography inputs @cindex gnutls cryptography inputs format -The inputs to GnuTLS cryptographic functions can be specified in + The inputs to GnuTLS cryptographic functions can be specified in several ways, both as primitive Emacs Lisp types or as lists. The list form is currently similar to how @code{md5} and @@ -4723,8 +4723,15 @@ IV used. @section Parsing HTML and XML @cindex parsing html -When Emacs is compiled with libxml2 support, the following functions -are available to parse HTML or XML text into Lisp object trees. + Emacs can be compiled with built-in libxml2 support. + +@defun libxml-available-p +This function returns non-@code{nil} if built-in libxml2 support is +available in this Emacs session. +@end defun + +When libxml2 support is available, the following functions can be used +to parse HTML or XML text into Lisp object trees. @defun libxml-parse-html-region start end &optional base-url discard-comments This function parses the text between @var{start} and @var{end} as @@ -4791,9 +4798,9 @@ about syntax). @cindex DOM @cindex Document Object Model -The @acronym{DOM} returned by @code{libxml-parse-html-region} (and the -other @acronym{XML} parsing functions) is a tree structure where each -node has a node name (called a @dfn{tag}), and optional key/value + The @acronym{DOM} returned by @code{libxml-parse-html-region} (and +the other @acronym{XML} parsing functions) is a tree structure where +each node has a node name (called a @dfn{tag}), and optional key/value @dfn{attribute} list, and then a list of @dfn{child nodes}. The child nodes are either strings or @acronym{DOM} objects. diff --git a/etc/NEWS b/etc/NEWS index 9ae36bdb032..f9481405e4e 100644 --- a/etc/NEWS +++ b/etc/NEWS @@ -39,6 +39,14 @@ text. +++ ** New function 'logcount' calculates an integer's Hamming weight. ++++ +** New function 'libxml-available-p'. +This function returns non-nil if libxml support is both compiled in +and available at run time. Lisp programs should use this function to +detect built-in libxml support, instead of testing for that +indirectly, e.g., by checking that functions like +'libxml-parse-html-region' return nil. + * Editing Changes in Emacs 27.1 diff --git a/src/emacs.c b/src/emacs.c index 0fe7d9113b4..808abcd9aa2 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 78843483edc..1ce32f33420 100644 --- a/src/lisp.h +++ b/src/lisp.h @@ -4391,9 +4391,9 @@ 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 d087a34a5e0..7afaa63c421 100644 --- a/src/xml.c +++ b/src/xml.c @@ -18,15 +18,15 @@ along with GNU Emacs. If not, see . */ #include +#include "lisp.h" +#include "buffer.h" + #ifdef HAVE_LIBXML2 #include #include #include -#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 */ -- 2.39.2