1 /*
2  *
3   ***** BEGIN LICENSE BLOCK *****
4 
5   Copyright (C) 2009-2016 Olof Hagsand and Benny Holmgren
6   Copyright (C) 2017-2020 Olof Hagsand
7 
8   This file is part of CLIXON.
9 
10   Licensed under the Apache License, Version 2.0 (the "License");
11   you may not use this file except in compliance with the License.
12   You may obtain a copy of the License at
13 
14     http://www.apache.org/licenses/LICENSE-2.0
15 
16   Unless required by applicable law or agreed to in writing, software
17   distributed under the License is distributed on an "AS IS" BASIS,
18   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19   See the License for the specific language governing permissions and
20   limitations under the License.
21 
22   Alternatively, the contents of this file may be used under the terms of
23   the GNU General Public License Version 3 or later (the "GPL"),
24   in which case the provisions of the GPL are applicable instead
25   of those above. If you wish to allow use of your version of this file only
26   under the terms of the GPL, and not to allow others to
27   use your version of this file under the terms of Apache License version 2,
28   indicate your decision by deleting the provisions above and replace them with
29   the  notice and other provisions required by the GPL. If you do not delete
30   the provisions above, a recipient may use your version of this file under
31   the terms of any one of the Apache License version 2 or the GPL.
32 
33   ***** END LICENSE BLOCK *****
34 
35  * Clixon XML XPATH 1.0 according to https://www.w3.org/TR/xpath-10
36  * This file defines XPATH contexts using in traversing the XPATH parse tree.
37  */
38 #ifndef _CLIXON_XPATH_CTX_H
39 #define _CLIXON_XPATH_CTX_H
40 
41 /*
42  * Types
43  */
44 
45 /*! XPATH expression type
46  * An expression is evaluated to yield an object, which has one of the following four basic types:
47  *  node-set (an unordered collection of nodes without duplicates)
48  *  boolean (true or false)
49  *  number (a floating-point number)
50  *  string (a sequence of UCS characters)
51  */
52 enum xp_objtype{
53     XT_NODESET,
54     XT_BOOL,
55     XT_NUMBER,
56     XT_STRING
57 };
58 
59 /* Expression evaluation occurs with respect to a context. XSLT and XPointer specify how the
60  * context is determined for XPath expressions used in XSLT and XPointer respectively. The
61  * context consists of:
62  *  a node (the context node)
63  *  a pair of non-zero positive integers (the context position and the context size)
64  *  a set of variable bindings
65  *  a function library
66  *  the set of namespace declarations in scope for the expression
67 
68  * For each node in the node-set to be filtered, the PredicateExpr is
69  * evaluated with that node as the context node, with the number of nodes
70  * in the node-set as the context size, and with the proximity position
71  * of the node in the node-set with respect to the axis as the context
72  * position; if PredicateExpr evaluates to true for that node, the node
73  * is included in the new node-set; otherwise, it is not included.
74  */
75 struct xp_ctx{
76     enum xp_objtype xc_type;
77     cxobj         **xc_nodeset; /* if type XT_NODESET */
78     int             xc_size;    /* Length of nodeset */
79     int             xc_bool;    /* if xc_type XT_BOOL */
80     double          xc_number;  /* if xc_type XT_NUMBER */
81     char           *xc_string;  /* if xc_type XT_STRING */
82     cxobj          *xc_node;    /* Node in nodeset XXX maybe not needed*/
83     cxobj          *xc_initial; /* RFC 7960 10.1.1 extension: for current() */
84     int             xc_descendant;  /* // */
85     /* NYI: a set of variable bindings, set of namespace declarations */
86 };
87 typedef struct xp_ctx xp_ctx;
88 
89 /*
90  * Variables
91  */
92 extern const map_str2int ctxmap[];
93 
94 /*
95  * Prototypes
96  */
97 int ctx_free(xp_ctx *xc);
98 xp_ctx *ctx_dup(xp_ctx *xc);
99 int ctx_nodeset_replace(xp_ctx *xc, cxobj **vec, size_t veclen);
100 int ctx_print_cb(cbuf *cb, xp_ctx *xc, int indent, char *str);
101 int ctx_print(FILE *f, xp_ctx *xc, char *str);
102 int ctx2boolean(xp_ctx *xc);
103 int ctx2string(xp_ctx *xc, char **str0);
104 int ctx2number(xp_ctx *xc, double *n0);
105 
106 #endif /* _CLIXON_XPATH_CTX_H */
107