libcli/wsp: Add support for simplified Advanced Query Syntax

Add support to parse AQS-like (Advanced query syntax)

AQS - see https://learn.microsoft.com/en-gb/windows/win32/search/-search-3x-advancedquerysyntax

The basic (AQS) syntax is supported e.g. a query is built of a sequence of
queries connected by AND, OR and NOT where the query elements are
essentially restrictions defined by a property. There are some
limitations on the operators supported[1] and additionally some things
like enumerated ranges are not supported at all and range values are not
delimited as specified [2]. Some special cases that you see in the
windows search UI are exceptions [3] which are handled more or less as keywords

Some examples:

The following are all exactly the same query just expressed using
different variations of the syntax

'ALL:($<p403 OR $<p404) AND System.Kind:picture AND Scope:"FILE://somemachine/someshare" AND > System.Size:10241-102401'

'ALL:$<p403 OR ALL:$<p404 AND System.Kind:picture AND Scope:"FILE://somemachine/someshare" AND > System.Size:>=10241 AND System.Size:<102401'

'ALL:$<p403 OR ALL:$<p404 AND System.Kind:picture AND Scope:"FILE://somemachine/someshare" AND > System.Size:small'

The queries above by default select the property System.ItemUrl as the
one and only column returned, the query parameter however accepts a
variation to the AQS like syntax to allow arbitrary columns to be
selected e.g.

'SELECT System.ItemName, System.ItemURL, System.Size WHERE ALL:$<p403 OR ALL:$<p404 AND System.Kind:picture AND Scope:"FILE://somemachine/someshare" AND System.Size:small'

[1] supported operators
    -------------------
    =    Equals
    !=   Not Equals
    >    Greater than
    <    Less than
    >=   Greater than or equals
    <=   Less than or equals

    $=   equals
    $<   starts with
[2] ranges are specified as value-value instead of value..value (seems
    my flex/bison skills are not good enough and couldn't get that to
    work with '..'

[3] The windows UI has shortcut ranges (presumably represented as enumerated
    ranges) providing date ranges like 'today', 'tomorrow',
   'lastweek' etc. and similarly sizes like "empty, tiny, small, large..."

   These are supported (but implemented as keywords)

Signed-off-by: Noel Power <[email protected]>
Reviewed-by: Andrew Bartlett <[email protected]>

libcli/wsp/wscript_build

@@ -0,0 +1,33 @@
+#!/usr/bin/env python
+
+#default flex recepie doesn't create a header file
+bld.SAMBA_GENERATOR('wsp_flex',
+	source='wsp_aqs_lexer.l',
+	target='wsp_aqs_lexer.h wsp_aqs_lexer.c',
+	group='build_source',
+	rule='${FLEX} --header-file=${TGT[0].abspath(env)} --outfile=${TGT[1].abspath(env)} ${SRC[0].abspath(env)}',
+	enabled=bld.env.with_wsp
+	)
+
+# With centos7-o3 CI job (and gcc 4.8.5) we get
+# an error with -Wstrict-overflow.
+# Same code is good with gcc version
+# gcc 8.5.0 (centos8) and whatever versions of
+# gcc we have in the other XXXX-o3 images.
+# We turn off strict-overflow just for this generated
+# file
+parser_cflags=''
+if bld.CONFIG_SET('HAVE_WNO_STRICT_OVERFLOW'):
+    parser_cflags += ' -Wno-strict-overflow'
+
+bld.SAMBA_SUBSYSTEM('LIBSAMBA_WSP_PARSER',
+	source='wsp_aqs_parser.y',
+	deps='talloc wsp_flex',
+	cflags_end=parser_cflags,
+	enabled=bld.env.with_wsp
+	)
+bld.SAMBA_SUBSYSTEM('LIBSAMBA_WSP',
+	source='wsp_aqs.c wsp_aqs_lexer.c',
+	public_deps='LIBSAMBA_WSP_PARSER',
+	enabled=bld.env.with_wsp
+	)