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mariadb/sql/item_xmlfunc.cc
unknown 64d6d8334f merge 5.3 -> 5.5
2013-09-25 17:16:13 +03:00

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/* Copyright (c) 2005, 2011, Oracle and/or its affiliates.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#ifdef __GNUC__
#pragma implementation
#endif
#include "sql_priv.h"
/*
It is necessary to include set_var.h instead of item.h because there
are dependencies on include order for set_var.h and item.h. This
will be resolved later.
*/
#include "sql_class.h" // set_var.h: THD
#include "set_var.h"
#include "my_xml.h"
#include "sp_pcontext.h"
#include "sql_class.h" // THD
/*
TODO: future development directions:
1. add real constants for XPATH_NODESET_CMP and XPATH_NODESET
into enum Type in item.h.
2. add nodeset_to_nodeset_comparator
3. add lacking functions:
- name()
- lang()
- string()
- id()
- translate()
- local-name()
- starts-with()
- namespace-uri()
- substring-after()
- normalize-space()
- substring-before()
4. add lacking axis:
- following-sibling
- following,
- preceding-sibling
- preceding
*/
/* Structure to store a parsed XML tree */
typedef struct my_xml_node_st
{
uint level; /* level in XML tree, 0 means root node */
enum my_xml_node_type type; /* node type: node, or attribute, or text */
uint parent; /* link to the parent */
const char *beg; /* beginning of the name or text */
const char *end; /* end of the name or text */
const char *tagend; /* where this tag ends */
} MY_XML_NODE;
/* Lexical analizer token */
typedef struct my_xpath_lex_st
{
int term; /* token type, see MY_XPATH_LEX_XXXXX below */
const char *beg; /* beginnign of the token */
const char *end; /* end of the token */
} MY_XPATH_LEX;
/* Structure to store nodesets */
typedef struct my_xpath_flt_st
{
uint num; /* absolute position in MY_XML_NODE array */
uint pos; /* relative position in context */
uint size; /* context size */
} MY_XPATH_FLT;
/* XPath function creator */
typedef struct my_xpath_function_names_st
{
const char *name; /* function name */
size_t length; /* function name length */
size_t minargs; /* min number of arguments */
size_t maxargs; /* max number of arguments */
Item *(*create)(struct my_xpath_st *xpath, Item **args, uint nargs);
} MY_XPATH_FUNC;
/* XPath query parser */
typedef struct my_xpath_st
{
int debug;
MY_XPATH_LEX query; /* Whole query */
MY_XPATH_LEX lasttok; /* last scanned token */
MY_XPATH_LEX prevtok; /* previous scanned token */
int axis; /* last scanned axis */
int extra; /* last scanned "extra", context dependent */
MY_XPATH_FUNC *func; /* last scanned function creator */
Item *item; /* current expression */
Item *context; /* last scanned context */
Item *rootelement; /* The root element */
String *context_cache; /* last context provider */
String *pxml; /* Parsed XML, an array of MY_XML_NODE */
CHARSET_INFO *cs; /* character set/collation string comparison */
int error;
} MY_XPATH;
/* Dynamic array of MY_XPATH_FLT */
class XPathFilter :public String
{
public:
XPathFilter() :String() {}
inline bool append_element(MY_XPATH_FLT *flt)
{
String *str= this;
return str->append((const char*)flt, (uint32) sizeof(MY_XPATH_FLT));
}
inline bool append_element(uint32 num, uint32 pos)
{
MY_XPATH_FLT add;
add.num= num;
add.pos= pos;
add.size= 0;
return append_element(&add);
}
inline bool append_element(uint32 num, uint32 pos, uint32 size)
{
MY_XPATH_FLT add;
add.num= num;
add.pos= pos;
add.size= size;
return append_element(&add);
}
inline MY_XPATH_FLT *element(uint i)
{
return (MY_XPATH_FLT*) (ptr() + i * sizeof(MY_XPATH_FLT));
}
inline uint32 numelements()
{
return length() / sizeof(MY_XPATH_FLT);
}
};
/*
Common features of the functions returning a node set.
*/
class Item_nodeset_func :public Item_str_func
{
protected:
String tmp_value, tmp2_value;
MY_XPATH_FLT *fltbeg, *fltend;
MY_XML_NODE *nodebeg, *nodeend;
uint numnodes;
public:
String *pxml;
String context_cache;
Item_nodeset_func(String *pxml_arg) :Item_str_func(), pxml(pxml_arg) {}
Item_nodeset_func(Item *a, String *pxml_arg)
:Item_str_func(a), pxml(pxml_arg) {}
Item_nodeset_func(Item *a, Item *b, String *pxml_arg)
:Item_str_func(a, b), pxml(pxml_arg) {}
Item_nodeset_func(Item *a, Item *b, Item *c, String *pxml_arg)
:Item_str_func(a,b,c), pxml(pxml_arg) {}
void prepare_nodes()
{
nodebeg= (MY_XML_NODE*) pxml->ptr();
nodeend= (MY_XML_NODE*) (pxml->ptr() + pxml->length());
numnodes= nodeend - nodebeg;
}
void prepare(String *nodeset)
{
prepare_nodes();
String *res= args[0]->val_nodeset(&tmp_value);
fltbeg= (MY_XPATH_FLT*) res->ptr();
fltend= (MY_XPATH_FLT*) (res->ptr() + res->length());
nodeset->length(0);
}
enum Type type() const { return XPATH_NODESET; }
String *val_str(String *str)
{
prepare_nodes();
String *res= val_nodeset(&tmp2_value);
fltbeg= (MY_XPATH_FLT*) res->ptr();
fltend= (MY_XPATH_FLT*) (res->ptr() + res->length());
String active;
active.alloc(numnodes);
bzero((char*) active.ptr(), numnodes);
for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++)
{
MY_XML_NODE *node;
uint j;
for (j=0, node= nodebeg ; j < numnodes; j++, node++)
{
if (node->type == MY_XML_NODE_TEXT &&
node->parent == flt->num)
active[j]= 1;
}
}
str->length(0);
str->set_charset(collation.collation);
for (uint i=0 ; i < numnodes; i++)
{
if(active[i])
{
if (str->length())
str->append(" ", 1, &my_charset_latin1);
str->append(nodebeg[i].beg, nodebeg[i].end - nodebeg[i].beg);
}
}
return str;
}
enum Item_result result_type () const { return STRING_RESULT; }
void fix_length_and_dec()
{
max_length= MAX_BLOB_WIDTH;
collation.collation= pxml->charset();
}
const char *func_name() const { return "nodeset"; }
bool check_vcol_func_processor(uchar *int_arg)
{
return trace_unsupported_by_check_vcol_func_processor(func_name());
}
};
/* Returns an XML root */
class Item_nodeset_func_rootelement :public Item_nodeset_func
{
public:
Item_nodeset_func_rootelement(String *pxml): Item_nodeset_func(pxml) {}
const char *func_name() const { return "xpath_rootelement"; }
String *val_nodeset(String *nodeset);
};
/* Returns a Union of two node sets */
class Item_nodeset_func_union :public Item_nodeset_func
{
public:
Item_nodeset_func_union(Item *a, Item *b, String *pxml)
:Item_nodeset_func(a, b, pxml) {}
const char *func_name() const { return "xpath_union"; }
String *val_nodeset(String *nodeset);
};
/* Makes one step towards the given axis */
class Item_nodeset_func_axisbyname :public Item_nodeset_func
{
const char *node_name;
uint node_namelen;
public:
Item_nodeset_func_axisbyname(Item *a, const char *n_arg, uint l_arg,
String *pxml):
Item_nodeset_func(a, pxml), node_name(n_arg), node_namelen(l_arg) { }
const char *func_name() const { return "xpath_axisbyname"; }
bool validname(MY_XML_NODE *n)
{
if (node_name[0] == '*')
return 1;
return (node_namelen == (uint) (n->end - n->beg)) &&
!memcmp(node_name, n->beg, node_namelen);
}
};
/* Returns self */
class Item_nodeset_func_selfbyname: public Item_nodeset_func_axisbyname
{
public:
Item_nodeset_func_selfbyname(Item *a, const char *n_arg, uint l_arg,
String *pxml):
Item_nodeset_func_axisbyname(a, n_arg, l_arg, pxml) {}
const char *func_name() const { return "xpath_selfbyname"; }
String *val_nodeset(String *nodeset);
};
/* Returns children */
class Item_nodeset_func_childbyname: public Item_nodeset_func_axisbyname
{
public:
Item_nodeset_func_childbyname(Item *a, const char *n_arg, uint l_arg,
String *pxml):
Item_nodeset_func_axisbyname(a, n_arg, l_arg, pxml) {}
const char *func_name() const { return "xpath_childbyname"; }
String *val_nodeset(String *nodeset);
};
/* Returns descendants */
class Item_nodeset_func_descendantbyname: public Item_nodeset_func_axisbyname
{
bool need_self;
public:
Item_nodeset_func_descendantbyname(Item *a, const char *n_arg, uint l_arg,
String *pxml, bool need_self_arg):
Item_nodeset_func_axisbyname(a, n_arg, l_arg, pxml),
need_self(need_self_arg) {}
const char *func_name() const { return "xpath_descendantbyname"; }
String *val_nodeset(String *nodeset);
};
/* Returns ancestors */
class Item_nodeset_func_ancestorbyname: public Item_nodeset_func_axisbyname
{
bool need_self;
public:
Item_nodeset_func_ancestorbyname(Item *a, const char *n_arg, uint l_arg,
String *pxml, bool need_self_arg):
Item_nodeset_func_axisbyname(a, n_arg, l_arg, pxml),
need_self(need_self_arg) {}
const char *func_name() const { return "xpath_ancestorbyname"; }
String *val_nodeset(String *nodeset);
};
/* Returns parents */
class Item_nodeset_func_parentbyname: public Item_nodeset_func_axisbyname
{
public:
Item_nodeset_func_parentbyname(Item *a, const char *n_arg, uint l_arg,
String *pxml):
Item_nodeset_func_axisbyname(a, n_arg, l_arg, pxml) {}
const char *func_name() const { return "xpath_parentbyname"; }
String *val_nodeset(String *nodeset);
};
/* Returns attributes */
class Item_nodeset_func_attributebyname: public Item_nodeset_func_axisbyname
{
public:
Item_nodeset_func_attributebyname(Item *a, const char *n_arg, uint l_arg,
String *pxml):
Item_nodeset_func_axisbyname(a, n_arg, l_arg, pxml) {}
const char *func_name() const { return "xpath_attributebyname"; }
String *val_nodeset(String *nodeset);
};
/*
Condition iterator: goes through all nodes in the current
context and checks a condition, returning those nodes
giving TRUE condition result.
*/
class Item_nodeset_func_predicate :public Item_nodeset_func
{
public:
Item_nodeset_func_predicate(Item *a, Item *b, String *pxml):
Item_nodeset_func(a, b, pxml) {}
const char *func_name() const { return "xpath_predicate"; }
String *val_nodeset(String *nodeset);
};
/* Selects nodes with a given position in context */
class Item_nodeset_func_elementbyindex :public Item_nodeset_func
{
public:
Item_nodeset_func_elementbyindex(Item *a, Item *b, String *pxml):
Item_nodeset_func(a, b, pxml) { }
const char *func_name() const { return "xpath_elementbyindex"; }
String *val_nodeset(String *nodeset);
};
/*
We need to distinguish a number from a boolean:
a[1] and a[true] are different things in XPath.
*/
class Item_bool :public Item_int
{
public:
Item_bool(int32 i): Item_int(i) {}
const char *func_name() const { return "xpath_bool"; }
bool is_bool_func() { return 1; }
};
/*
Converts its argument into a boolean value.
* a number is true if it is non-zero
* a node-set is true if and only if it is non-empty
* a string is true if and only if its length is non-zero
*/
class Item_xpath_cast_bool :public Item_int_func
{
String *pxml;
String tmp_value;
public:
Item_xpath_cast_bool(Item *a, String *pxml_arg)
:Item_int_func(a), pxml(pxml_arg) {}
const char *func_name() const { return "xpath_cast_bool"; }
bool is_bool_func() { return 1; }
longlong val_int()
{
if (args[0]->type() == XPATH_NODESET)
{
String *flt= args[0]->val_nodeset(&tmp_value);
return flt->length() == sizeof(MY_XPATH_FLT) ? 1 : 0;
}
return args[0]->val_real() ? 1 : 0;
}
};
/*
Converts its argument into a number
*/
class Item_xpath_cast_number :public Item_real_func
{
public:
Item_xpath_cast_number(Item *a): Item_real_func(a) {}
const char *func_name() const { return "xpath_cast_number"; }
virtual double val_real() { return args[0]->val_real(); }
};
/*
Context cache, for predicate
*/
class Item_nodeset_context_cache :public Item_nodeset_func
{
public:
String *string_cache;
Item_nodeset_context_cache(String *str_arg, String *pxml):
Item_nodeset_func(pxml), string_cache(str_arg) { }
String *val_nodeset(String *res)
{ return string_cache; }
void fix_length_and_dec() { max_length= MAX_BLOB_WIDTH; }
};
class Item_func_xpath_position :public Item_int_func
{
String *pxml;
String tmp_value;
public:
Item_func_xpath_position(Item *a, String *p)
:Item_int_func(a), pxml(p) {}
const char *func_name() const { return "xpath_position"; }
void fix_length_and_dec() { max_length=10; }
longlong val_int()
{
String *flt= args[0]->val_nodeset(&tmp_value);
if (flt->length() == sizeof(MY_XPATH_FLT))
return ((MY_XPATH_FLT*)flt->ptr())->pos + 1;
return 0;
}
};
class Item_func_xpath_count :public Item_int_func
{
String *pxml;
String tmp_value;
public:
Item_func_xpath_count(Item *a, String *p)
:Item_int_func(a), pxml(p) {}
const char *func_name() const { return "xpath_count"; }
void fix_length_and_dec() { max_length=10; }
longlong val_int()
{
uint predicate_supplied_context_size;
String *res= args[0]->val_nodeset(&tmp_value);
if (res->length() == sizeof(MY_XPATH_FLT) &&
(predicate_supplied_context_size= ((MY_XPATH_FLT*)res->ptr())->size))
return predicate_supplied_context_size;
return res->length() / sizeof(MY_XPATH_FLT);
}
};
class Item_func_xpath_sum :public Item_real_func
{
String *pxml;
String tmp_value;
public:
Item_func_xpath_sum(Item *a, String *p)
:Item_real_func(a), pxml(p) {}
const char *func_name() const { return "xpath_sum"; }
double val_real()
{
double sum= 0;
String *res= args[0]->val_nodeset(&tmp_value);
MY_XPATH_FLT *fltbeg= (MY_XPATH_FLT*) res->ptr();
MY_XPATH_FLT *fltend= (MY_XPATH_FLT*) (res->ptr() + res->length());
uint numnodes= pxml->length() / sizeof(MY_XML_NODE);
MY_XML_NODE *nodebeg= (MY_XML_NODE*) pxml->ptr();
for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++)
{
MY_XML_NODE *self= &nodebeg[flt->num];
for (uint j= flt->num + 1; j < numnodes; j++)
{
MY_XML_NODE *node= &nodebeg[j];
if (node->level <= self->level)
break;
if ((node->parent == flt->num) &&
(node->type == MY_XML_NODE_TEXT))
{
char *end;
int err;
double add= my_strntod(collation.collation, (char*) node->beg,
node->end - node->beg, &end, &err);
if (!err)
sum+= add;
}
}
}
return sum;
}
};
class Item_nodeset_to_const_comparator :public Item_bool_func
{
String *pxml;
String tmp_nodeset;
public:
Item_nodeset_to_const_comparator(Item *nodeset, Item *cmpfunc, String *p)
:Item_bool_func(nodeset,cmpfunc), pxml(p) {}
enum Type type() const { return XPATH_NODESET_CMP; };
const char *func_name() const { return "xpath_nodeset_to_const_comparator"; }
bool is_bool_func() { return 1; }
bool check_vcol_func_processor(uchar *int_arg)
{
return trace_unsupported_by_check_vcol_func_processor(func_name());
}
longlong val_int()
{
Item_func *comp= (Item_func*)args[1];
Item_string *fake= (Item_string*)(comp->arguments()[0]);
String *res= args[0]->val_nodeset(&tmp_nodeset);
MY_XPATH_FLT *fltbeg= (MY_XPATH_FLT*) res->ptr();
MY_XPATH_FLT *fltend= (MY_XPATH_FLT*) (res->ptr() + res->length());
MY_XML_NODE *nodebeg= (MY_XML_NODE*) pxml->ptr();
uint numnodes= pxml->length() / sizeof(MY_XML_NODE);
for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++)
{
MY_XML_NODE *self= &nodebeg[flt->num];
for (uint j= flt->num + 1; j < numnodes; j++)
{
MY_XML_NODE *node= &nodebeg[j];
if (node->level <= self->level)
break;
if ((node->parent == flt->num) &&
(node->type == MY_XML_NODE_TEXT))
{
fake->str_value.set(node->beg, node->end - node->beg,
collation.collation);
if (args[1]->val_int())
return 1;
}
}
}
return 0;
}
};
String *Item_nodeset_func_rootelement::val_nodeset(String *nodeset)
{
nodeset->length(0);
((XPathFilter*)nodeset)->append_element(0, 0);
return nodeset;
}
String * Item_nodeset_func_union::val_nodeset(String *nodeset)
{
uint num_nodes= pxml->length() / sizeof(MY_XML_NODE);
String set0, *s0= args[0]->val_nodeset(&set0);
String set1, *s1= args[1]->val_nodeset(&set1);
String both_str;
both_str.alloc(num_nodes);
char *both= (char*) both_str.ptr();
bzero((void*)both, num_nodes);
MY_XPATH_FLT *flt;
fltbeg= (MY_XPATH_FLT*) s0->ptr();
fltend= (MY_XPATH_FLT*) (s0->ptr() + s0->length());
for (flt= fltbeg; flt < fltend; flt++)
both[flt->num]= 1;
fltbeg= (MY_XPATH_FLT*) s1->ptr();
fltend= (MY_XPATH_FLT*) (s1->ptr() + s1->length());
for (flt= fltbeg; flt < fltend; flt++)
both[flt->num]= 1;
nodeset->length(0);
for (uint i= 0, pos= 0; i < num_nodes; i++)
{
if (both[i])
((XPathFilter*)nodeset)->append_element(i, pos++);
}
return nodeset;
}
String *Item_nodeset_func_selfbyname::val_nodeset(String *nodeset)
{
prepare(nodeset);
for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++)
{
uint pos= 0;
MY_XML_NODE *self= &nodebeg[flt->num];
if (validname(self))
((XPathFilter*)nodeset)->append_element(flt->num,pos++);
}
return nodeset;
}
String *Item_nodeset_func_childbyname::val_nodeset(String *nodeset)
{
prepare(nodeset);
for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++)
{
MY_XML_NODE *self= &nodebeg[flt->num];
for (uint pos= 0, j= flt->num + 1 ; j < numnodes; j++)
{
MY_XML_NODE *node= &nodebeg[j];
if (node->level <= self->level)
break;
if ((node->parent == flt->num) &&
(node->type == MY_XML_NODE_TAG) &&
validname(node))
((XPathFilter*)nodeset)->append_element(j, pos++);
}
}
return nodeset;
}
String *Item_nodeset_func_descendantbyname::val_nodeset(String *nodeset)
{
prepare(nodeset);
for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++)
{
uint pos= 0;
MY_XML_NODE *self= &nodebeg[flt->num];
if (need_self && validname(self))
((XPathFilter*)nodeset)->append_element(flt->num,pos++);
for (uint j= flt->num + 1 ; j < numnodes ; j++)
{
MY_XML_NODE *node= &nodebeg[j];
if (node->level <= self->level)
break;
if ((node->type == MY_XML_NODE_TAG) && validname(node))
((XPathFilter*)nodeset)->append_element(j,pos++);
}
}
return nodeset;
}
String *Item_nodeset_func_ancestorbyname::val_nodeset(String *nodeset)
{
char *active;
String active_str;
prepare(nodeset);
active_str.alloc(numnodes);
active= (char*) active_str.ptr();
bzero((void*)active, numnodes);
uint pos= 0;
for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++)
{
/*
Go to the root and add all nodes on the way.
Don't add the root if context is the root itelf
*/
MY_XML_NODE *self= &nodebeg[flt->num];
if (need_self && validname(self))
{
active[flt->num]= 1;
pos++;
}
for (uint j= self->parent; nodebeg[j].parent != j; j= nodebeg[j].parent)
{
if (flt->num && validname(&nodebeg[j]))
{
active[j]= 1;
pos++;
}
}
}
for (uint j= 0; j < numnodes ; j++)
{
if (active[j])
((XPathFilter*)nodeset)->append_element(j, --pos);
}
return nodeset;
}
String *Item_nodeset_func_parentbyname::val_nodeset(String *nodeset)
{
char *active;
String active_str;
prepare(nodeset);
active_str.alloc(numnodes);
active= (char*) active_str.ptr();
bzero((void*)active, numnodes);
for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++)
{
uint j= nodebeg[flt->num].parent;
if (flt->num && validname(&nodebeg[j]))
active[j]= 1;
}
for (uint j= 0, pos= 0; j < numnodes ; j++)
{
if (active[j])
((XPathFilter*)nodeset)->append_element(j, pos++);
}
return nodeset;
}
String *Item_nodeset_func_attributebyname::val_nodeset(String *nodeset)
{
prepare(nodeset);
for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++)
{
MY_XML_NODE *self= &nodebeg[flt->num];
for (uint pos=0, j= flt->num + 1 ; j < numnodes; j++)
{
MY_XML_NODE *node= &nodebeg[j];
if (node->level <= self->level)
break;
if ((node->parent == flt->num) &&
(node->type == MY_XML_NODE_ATTR) &&
validname(node))
((XPathFilter*)nodeset)->append_element(j, pos++);
}
}
return nodeset;
}
String *Item_nodeset_func_predicate::val_nodeset(String *str)
{
Item_nodeset_func *nodeset_func= (Item_nodeset_func*) args[0];
Item_func *comp_func= (Item_func*)args[1];
uint pos= 0, size;
prepare(str);
size= fltend - fltbeg;
for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++)
{
nodeset_func->context_cache.length(0);
((XPathFilter*)(&nodeset_func->context_cache))->append_element(flt->num,
flt->pos,
size);
if (comp_func->val_int())
((XPathFilter*)str)->append_element(flt->num, pos++);
}
return str;
}
String *Item_nodeset_func_elementbyindex::val_nodeset(String *nodeset)
{
Item_nodeset_func *nodeset_func= (Item_nodeset_func*) args[0];
prepare(nodeset);
MY_XPATH_FLT *flt;
uint pos, size= fltend - fltbeg;
for (pos= 0, flt= fltbeg; flt < fltend; flt++)
{
nodeset_func->context_cache.length(0);
((XPathFilter*)(&nodeset_func->context_cache))->append_element(flt->num,
flt->pos,
size);
int index= (int) (args[1]->val_int()) - 1;
if (index >= 0 && (flt->pos == (uint) index || args[1]->is_bool_func()))
((XPathFilter*)nodeset)->append_element(flt->num, pos++);
}
return nodeset;
}
/*
If item is a node set, then casts it to boolean,
otherwise returns the item itself.
*/
static Item* nodeset2bool(MY_XPATH *xpath, Item *item)
{
if (item->type() == Item::XPATH_NODESET)
return new Item_xpath_cast_bool(item, xpath->pxml);
return item;
}
/*
XPath lexical tokens
*/
#define MY_XPATH_LEX_DIGITS 'd'
#define MY_XPATH_LEX_IDENT 'i'
#define MY_XPATH_LEX_STRING 's'
#define MY_XPATH_LEX_SLASH '/'
#define MY_XPATH_LEX_LB '['
#define MY_XPATH_LEX_RB ']'
#define MY_XPATH_LEX_LP '('
#define MY_XPATH_LEX_RP ')'
#define MY_XPATH_LEX_EQ '='
#define MY_XPATH_LEX_LESS '<'
#define MY_XPATH_LEX_GREATER '>'
#define MY_XPATH_LEX_AT '@'
#define MY_XPATH_LEX_COLON ':'
#define MY_XPATH_LEX_ASTERISK '*'
#define MY_XPATH_LEX_DOT '.'
#define MY_XPATH_LEX_VLINE '|'
#define MY_XPATH_LEX_MINUS '-'
#define MY_XPATH_LEX_PLUS '+'
#define MY_XPATH_LEX_EXCL '!'
#define MY_XPATH_LEX_COMMA ','
#define MY_XPATH_LEX_DOLLAR '$'
#define MY_XPATH_LEX_ERROR 'A'
#define MY_XPATH_LEX_EOF 'B'
#define MY_XPATH_LEX_AND 'C'
#define MY_XPATH_LEX_OR 'D'
#define MY_XPATH_LEX_DIV 'E'
#define MY_XPATH_LEX_MOD 'F'
#define MY_XPATH_LEX_FUNC 'G'
#define MY_XPATH_LEX_NODETYPE 'H'
#define MY_XPATH_LEX_AXIS 'I'
#define MY_XPATH_LEX_LE 'J'
#define MY_XPATH_LEX_GE 'K'
/*
XPath axis type
*/
#define MY_XPATH_AXIS_ANCESTOR 0
#define MY_XPATH_AXIS_ANCESTOR_OR_SELF 1
#define MY_XPATH_AXIS_ATTRIBUTE 2
#define MY_XPATH_AXIS_CHILD 3
#define MY_XPATH_AXIS_DESCENDANT 4
#define MY_XPATH_AXIS_DESCENDANT_OR_SELF 5
#define MY_XPATH_AXIS_FOLLOWING 6
#define MY_XPATH_AXIS_FOLLOWING_SIBLING 7
#define MY_XPATH_AXIS_NAMESPACE 8
#define MY_XPATH_AXIS_PARENT 9
#define MY_XPATH_AXIS_PRECEDING 10
#define MY_XPATH_AXIS_PRECEDING_SIBLING 11
#define MY_XPATH_AXIS_SELF 12
/*
Create scalar comparator
SYNOPSYS
Create a comparator function for scalar arguments,
for the given arguments and operation.
RETURN
The newly created item.
*/
static Item *eq_func(int oper, Item *a, Item *b)
{
switch (oper)
{
case '=': return new Item_func_eq(a, b);
case '!': return new Item_func_ne(a, b);
case MY_XPATH_LEX_GE: return new Item_func_ge(a, b);
case MY_XPATH_LEX_LE: return new Item_func_le(a, b);
case MY_XPATH_LEX_GREATER: return new Item_func_gt(a, b);
case MY_XPATH_LEX_LESS: return new Item_func_lt(a, b);
}
return 0;
}
/*
Create scalar comparator
SYNOPSYS
Create a comparator function for scalar arguments,
for the given arguments and reverse operation, e.g.
A > B is converted into B < A
RETURN
The newly created item.
*/
static Item *eq_func_reverse(int oper, Item *a, Item *b)
{
switch (oper)
{
case '=': return new Item_func_eq(a, b);
case '!': return new Item_func_ne(a, b);
case MY_XPATH_LEX_GE: return new Item_func_le(a, b);
case MY_XPATH_LEX_LE: return new Item_func_ge(a, b);
case MY_XPATH_LEX_GREATER: return new Item_func_lt(a, b);
case MY_XPATH_LEX_LESS: return new Item_func_gt(a, b);
}
return 0;
}
/*
Create a comparator
SYNOPSYS
Create a comparator for scalar or non-scalar arguments,
for the given arguments and operation.
RETURN
The newly created item.
*/
static Item *create_comparator(MY_XPATH *xpath,
int oper, MY_XPATH_LEX *context,
Item *a, Item *b)
{
if (a->type() != Item::XPATH_NODESET &&
b->type() != Item::XPATH_NODESET)
{
return eq_func(oper, a, b); // two scalar arguments
}
else if (a->type() == Item::XPATH_NODESET &&
b->type() == Item::XPATH_NODESET)
{
uint len= xpath->query.end - context->beg;
set_if_smaller(len, 32);
my_printf_error(ER_UNKNOWN_ERROR,
"XPATH error: "
"comparison of two nodesets is not supported: '%.*s'",
MYF(0), len, context->beg);
return 0; // TODO: Comparison of two nodesets
}
else
{
/*
Compare a node set to a scalar value.
We just create a fake Item_string() argument,
which will be filled to the partular value
in a loop through all of the nodes in the node set.
*/
Item_string *fake= new Item_string("", 0, xpath->cs);
/* Don't cache fake because its value will be changed during comparison.*/
fake->set_used_tables(RAND_TABLE_BIT);
Item_nodeset_func *nodeset;
Item *scalar, *comp;
if (a->type() == Item::XPATH_NODESET)
{
nodeset= (Item_nodeset_func*) a;
scalar= b;
comp= eq_func(oper, (Item*)fake, scalar);
}
else
{
nodeset= (Item_nodeset_func*) b;
scalar= a;
comp= eq_func_reverse(oper, fake, scalar);
}
return new Item_nodeset_to_const_comparator(nodeset, comp, xpath->pxml);
}
}
/*
Create a step
SYNOPSYS
Create a step function for the given argument and axis.
RETURN
The newly created item.
*/
static Item* nametestfunc(MY_XPATH *xpath,
int type, Item *arg, const char *beg, uint len)
{
DBUG_ASSERT(arg != 0);
DBUG_ASSERT(arg->type() == Item::XPATH_NODESET);
DBUG_ASSERT(beg != 0);
DBUG_ASSERT(len > 0);
Item *res;
switch (type)
{
case MY_XPATH_AXIS_ANCESTOR:
res= new Item_nodeset_func_ancestorbyname(arg, beg, len, xpath->pxml, 0);
break;
case MY_XPATH_AXIS_ANCESTOR_OR_SELF:
res= new Item_nodeset_func_ancestorbyname(arg, beg, len, xpath->pxml, 1);
break;
case MY_XPATH_AXIS_PARENT:
res= new Item_nodeset_func_parentbyname(arg, beg, len, xpath->pxml);
break;
case MY_XPATH_AXIS_DESCENDANT:
res= new Item_nodeset_func_descendantbyname(arg, beg, len, xpath->pxml, 0);
break;
case MY_XPATH_AXIS_DESCENDANT_OR_SELF:
res= new Item_nodeset_func_descendantbyname(arg, beg, len, xpath->pxml, 1);
break;
case MY_XPATH_AXIS_ATTRIBUTE:
res= new Item_nodeset_func_attributebyname(arg, beg, len, xpath->pxml);
break;
case MY_XPATH_AXIS_SELF:
res= new Item_nodeset_func_selfbyname(arg, beg, len, xpath->pxml);
break;
default:
res= new Item_nodeset_func_childbyname(arg, beg, len, xpath->pxml);
}
return res;
}
/*
Tokens consisting of one character, for faster lexical analizer.
*/
static char simpletok[128]=
{
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
/*
! " # $ % & ' ( ) * + , - . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ?
@ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ \ ] ^ _
` a b c d e f g h i j k l m n o p q r s t u v w x y z { | } ~ <20>
*/
0,1,0,0,1,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,1,0,1,1,1,0,
1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0
};
/*
XPath keywords
*/
struct my_xpath_keyword_names_st
{
int tok;
const char *name;
size_t length;
int extra;
};
static struct my_xpath_keyword_names_st my_keyword_names[] =
{
{MY_XPATH_LEX_AND , "and" , 3, 0 },
{MY_XPATH_LEX_OR , "or" , 2, 0 },
{MY_XPATH_LEX_DIV , "div" , 3, 0 },
{MY_XPATH_LEX_MOD , "mod" , 3, 0 },
{0,NULL,0,0}
};
static struct my_xpath_keyword_names_st my_axis_names[]=
{
{MY_XPATH_LEX_AXIS,"ancestor" , 8,MY_XPATH_AXIS_ANCESTOR },
{MY_XPATH_LEX_AXIS,"ancestor-or-self" ,16,MY_XPATH_AXIS_ANCESTOR_OR_SELF },
{MY_XPATH_LEX_AXIS,"attribute" , 9,MY_XPATH_AXIS_ATTRIBUTE },
{MY_XPATH_LEX_AXIS,"child" , 5,MY_XPATH_AXIS_CHILD },
{MY_XPATH_LEX_AXIS,"descendant" ,10,MY_XPATH_AXIS_DESCENDANT },
{MY_XPATH_LEX_AXIS,"descendant-or-self",18,MY_XPATH_AXIS_DESCENDANT_OR_SELF},
{MY_XPATH_LEX_AXIS,"following" , 9,MY_XPATH_AXIS_FOLLOWING },
{MY_XPATH_LEX_AXIS,"following-sibling" ,17,MY_XPATH_AXIS_FOLLOWING_SIBLING },
{MY_XPATH_LEX_AXIS,"namespace" , 9,MY_XPATH_AXIS_NAMESPACE },
{MY_XPATH_LEX_AXIS,"parent" , 6,MY_XPATH_AXIS_PARENT },
{MY_XPATH_LEX_AXIS,"preceding" , 9,MY_XPATH_AXIS_PRECEDING },
{MY_XPATH_LEX_AXIS,"preceding-sibling" ,17,MY_XPATH_AXIS_PRECEDING_SIBLING },
{MY_XPATH_LEX_AXIS,"self" , 4,MY_XPATH_AXIS_SELF },
{0,NULL,0,0}
};
static struct my_xpath_keyword_names_st my_nodetype_names[]=
{
{MY_XPATH_LEX_NODETYPE, "comment" , 7, 0 },
{MY_XPATH_LEX_NODETYPE, "text" , 4, 0 },
{MY_XPATH_LEX_NODETYPE, "processing-instruction" , 22,0 },
{MY_XPATH_LEX_NODETYPE, "node" , 4, 0 },
{0,NULL,0,0}
};
/*
Lookup a keyword
SYNOPSYS
Check that the last scanned identifier is a keyword.
RETURN
- Token type, on lookup success.
- MY_XPATH_LEX_IDENT, on lookup failure.
*/
static int
my_xpath_keyword(MY_XPATH *x,
struct my_xpath_keyword_names_st *keyword_names,
const char *beg, const char *end)
{
struct my_xpath_keyword_names_st *k;
size_t length= end-beg;
for (k= keyword_names; k->name; k++)
{
if (length == k->length && !strncasecmp(beg, k->name, length))
{
x->extra= k->extra;
return k->tok;
}
}
return MY_XPATH_LEX_IDENT;
}
/*
Functions to create an item, a-la those in item_create.cc
*/
static Item *create_func_true(MY_XPATH *xpath, Item **args, uint nargs)
{
return new Item_bool(1);
}
static Item *create_func_false(MY_XPATH *xpath, Item **args, uint nargs)
{
return new Item_bool(0);
}
static Item *create_func_not(MY_XPATH *xpath, Item **args, uint nargs)
{
return new Item_func_not(nodeset2bool(xpath, args[0]));
}
static Item *create_func_ceiling(MY_XPATH *xpath, Item **args, uint nargs)
{
return new Item_func_ceiling(args[0]);
}
static Item *create_func_floor(MY_XPATH *xpath, Item **args, uint nargs)
{
return new Item_func_floor(args[0]);
}
static Item *create_func_bool(MY_XPATH *xpath, Item **args, uint nargs)
{
return new Item_xpath_cast_bool(args[0], xpath->pxml);
}
static Item *create_func_number(MY_XPATH *xpath, Item **args, uint nargs)
{
return new Item_xpath_cast_number(args[0]);
}
static Item *create_func_string_length(MY_XPATH *xpath, Item **args, uint nargs)
{
Item *arg= nargs ? args[0] : xpath->context;
return arg ? new Item_func_char_length(arg) : 0;
}
static Item *create_func_round(MY_XPATH *xpath, Item **args, uint nargs)
{
return new Item_func_round(args[0], new Item_int((char*)"0",0,1),0);
}
static Item *create_func_last(MY_XPATH *xpath, Item **args, uint nargs)
{
return xpath->context ?
new Item_func_xpath_count(xpath->context, xpath->pxml) : NULL;
}
static Item *create_func_position(MY_XPATH *xpath, Item **args, uint nargs)
{
return xpath->context ?
new Item_func_xpath_position(xpath->context, xpath->pxml) : NULL;
}
static Item *create_func_contains(MY_XPATH *xpath, Item **args, uint nargs)
{
return new Item_xpath_cast_bool(new Item_func_locate(args[0], args[1]),
xpath->pxml);
}
static Item *create_func_concat(MY_XPATH *xpath, Item **args, uint nargs)
{
return new Item_func_concat(args[0], args[1]);
}
static Item *create_func_substr(MY_XPATH *xpath, Item **args, uint nargs)
{
if (nargs == 2)
return new Item_func_substr(args[0], args[1]);
else
return new Item_func_substr(args[0], args[1], args[2]);
}
static Item *create_func_count(MY_XPATH *xpath, Item **args, uint nargs)
{
if (args[0]->type() != Item::XPATH_NODESET)
return 0;
return new Item_func_xpath_count(args[0], xpath->pxml);
}
static Item *create_func_sum(MY_XPATH *xpath, Item **args, uint nargs)
{
if (args[0]->type() != Item::XPATH_NODESET)
return 0;
return new Item_func_xpath_sum(args[0], xpath->pxml);
}
/*
Functions names. Separate lists for names with
lengths 3,4,5 and 6 for faster lookups.
*/
static MY_XPATH_FUNC my_func_names3[]=
{
{"sum", 3, 1 , 1 , create_func_sum},
{"not", 3, 1 , 1 , create_func_not},
{0 , 0, 0 , 0, 0}
};
static MY_XPATH_FUNC my_func_names4[]=
{
{"last", 4, 0, 0, create_func_last},
{"true", 4, 0, 0, create_func_true},
{"name", 4, 0, 1, 0},
{"lang", 4, 1, 1, 0},
{0 , 0, 0, 0, 0}
};
static MY_XPATH_FUNC my_func_names5[]=
{
{"count", 5, 1, 1, create_func_count},
{"false", 5, 0, 0, create_func_false},
{"floor", 5, 1, 1, create_func_floor},
{"round", 5, 1, 1, create_func_round},
{0 , 0, 0, 0, 0}
};
static MY_XPATH_FUNC my_func_names6[]=
{
{"concat", 6, 2, 255, create_func_concat},
{"number", 6, 0, 1 , create_func_number},
{"string", 6, 0, 1 , 0},
{0 , 0, 0, 0 , 0}
};
/* Other functions, with name longer than 6, all together */
static MY_XPATH_FUNC my_func_names[] =
{
{"id" , 2 , 1 , 1 , 0},
{"boolean" , 7 , 1 , 1 , create_func_bool},
{"ceiling" , 7 , 1 , 1 , create_func_ceiling},
{"position" , 8 , 0 , 0 , create_func_position},
{"contains" , 8 , 2 , 2 , create_func_contains},
{"substring" , 9 , 2 , 3 , create_func_substr},
{"translate" , 9 , 3 , 3 , 0},
{"local-name" , 10 , 0 , 1 , 0},
{"starts-with" , 11 , 2 , 2 , 0},
{"namespace-uri" , 13 , 0 , 1 , 0},
{"string-length" , 13 , 0 , 1 , create_func_string_length},
{"substring-after" , 15 , 2 , 2 , 0},
{"normalize-space" , 15 , 0 , 1 , 0},
{"substring-before" , 16 , 2 , 2 , 0},
{NULL,0,0,0,0}
};
/*
Lookup a function by name
SYNOPSYS
Lookup a function by its name.
RETURN
Pointer to a MY_XPATH_FUNC variable on success.
0 - on failure.
*/
MY_XPATH_FUNC *
my_xpath_function(const char *beg, const char *end)
{
MY_XPATH_FUNC *k, *function_names;
uint length= end-beg;
switch (length)
{
case 1: return 0;
case 3: function_names= my_func_names3; break;
case 4: function_names= my_func_names4; break;
case 5: function_names= my_func_names5; break;
case 6: function_names= my_func_names6; break;
default: function_names= my_func_names;
}
for (k= function_names; k->name; k++)
if (k->create && length == k->length && !strncasecmp(beg, k->name, length))
return k;
return NULL;
}
/* Initialize a lex analizer token */
static void
my_xpath_lex_init(MY_XPATH_LEX *lex,
const char *str, const char *strend)
{
lex->beg= str;
lex->end= strend;
}
/* Initialize an XPath query parser */
static void
my_xpath_init(MY_XPATH *xpath)
{
bzero((void*)xpath, sizeof(xpath[0]));
}
static int
my_xdigit(int c)
{
return ((c) >= '0' && (c) <= '9');
}
/*
Scan the next token
SYNOPSYS
Scan the next token from the input.
lex->term is set to the scanned token type.
lex->beg and lex->end are set to the beginnig
and to the end of the token.
RETURN
N/A
*/
static void
my_xpath_lex_scan(MY_XPATH *xpath,
MY_XPATH_LEX *lex, const char *beg, const char *end)
{
int ch, ctype, length;
for ( ; beg < end && *beg == ' ' ; beg++) ; // skip leading spaces
lex->beg= beg;
if (beg >= end)
{
lex->end= beg;
lex->term= MY_XPATH_LEX_EOF; // end of line reached
return;
}
// Check ident, or a function call, or a keyword
if ((length= xpath->cs->cset->ctype(xpath->cs, &ctype,
(const uchar*) beg,
(const uchar*) end)) > 0 &&
((ctype & (_MY_L | _MY_U)) || *beg == '_'))
{
// scan untill the end of the idenfitier
for (beg+= length;
(length= xpath->cs->cset->ctype(xpath->cs, &ctype,
(const uchar*) beg,
(const uchar*) end)) > 0 &&
((ctype & (_MY_L | _MY_U | _MY_NMR)) ||
*beg == '_' || *beg == '-' || *beg == '.') ;
beg+= length) /* no op */;
lex->end= beg;
if (beg < end)
{
if (*beg == '(')
{
/*
check if a function call, e.g.: count(/a/b)
or a nodetype test, e.g.: /a/b/text()
*/
if ((xpath->func= my_xpath_function(lex->beg, beg)))
lex->term= MY_XPATH_LEX_FUNC;
else
lex->term= my_xpath_keyword(xpath, my_nodetype_names,
lex->beg, beg);
return;
}
// check if an axis specifier, e.g.: /a/b/child::*
else if (*beg == ':' && beg + 1 < end && beg[1] == ':')
{
lex->term= my_xpath_keyword(xpath, my_axis_names,
lex->beg, beg);
return;
}
}
// check if a keyword
lex->term= my_xpath_keyword(xpath, my_keyword_names,
lex->beg, beg);
return;
}
ch= *beg++;
if (ch > 0 && ch < 128 && simpletok[ch])
{
// a token consisting of one character found
lex->end= beg;
lex->term= ch;
return;
}
if (my_xdigit(ch)) // a sequence of digits
{
for ( ; beg < end && my_xdigit(*beg) ; beg++) ;
lex->end= beg;
lex->term= MY_XPATH_LEX_DIGITS;
return;
}
if (ch == '"' || ch == '\'') // a string: either '...' or "..."
{
for ( ; beg < end && *beg != ch ; beg++) ;
if (beg < end)
{
lex->end= beg+1;
lex->term= MY_XPATH_LEX_STRING;
return;
}
else
{
// unexpected end-of-line, without closing quot sign
lex->end= end;
lex->term= MY_XPATH_LEX_ERROR;
return;
}
}
lex->end= beg;
lex->term= MY_XPATH_LEX_ERROR; // unknown character
return;
}
/*
Scan the given token
SYNOPSYS
Scan the given token and rotate lasttok to prevtok on success.
RETURN
1 - success
0 - failure
*/
static int
my_xpath_parse_term(MY_XPATH *xpath, int term)
{
if (xpath->lasttok.term == term && !xpath->error)
{
xpath->prevtok= xpath->lasttok;
my_xpath_lex_scan(xpath, &xpath->lasttok,
xpath->lasttok.end, xpath->query.end);
return 1;
}
return 0;
}
/*
Scan AxisName
SYNOPSYS
Scan an axis name and store the scanned axis type into xpath->axis.
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_AxisName(MY_XPATH *xpath)
{
int rc= my_xpath_parse_term(xpath, MY_XPATH_LEX_AXIS);
xpath->axis= xpath->extra;
return rc;
}
/*********************************************
** Grammar rules, according to http://www.w3.org/TR/xpath
** Implemented using recursive descendant method.
** All the following grammar processing functions accept
** a signle "xpath" argument and return 1 on success and 0 on error.
** They also modify "xpath" argument by creating new items.
*/
/* [9] PredicateExpr ::= Expr */
#define my_xpath_parse_PredicateExpr(x) my_xpath_parse_Expr((x))
/* [14] Expr ::= OrExpr */
#define my_xpath_parse_Expr(x) my_xpath_parse_OrExpr((x))
static int my_xpath_parse_LocationPath(MY_XPATH *xpath);
static int my_xpath_parse_AbsoluteLocationPath(MY_XPATH *xpath);
static int my_xpath_parse_RelativeLocationPath(MY_XPATH *xpath);
static int my_xpath_parse_AbbreviatedStep(MY_XPATH *xpath);
static int my_xpath_parse_Step(MY_XPATH *xpath);
static int my_xpath_parse_AxisSpecifier(MY_XPATH *xpath);
static int my_xpath_parse_NodeTest(MY_XPATH *xpath);
static int my_xpath_parse_AbbreviatedAxisSpecifier(MY_XPATH *xpath);
static int my_xpath_parse_NameTest(MY_XPATH *xpath);
static int my_xpath_parse_FunctionCall(MY_XPATH *xpath);
static int my_xpath_parse_Number(MY_XPATH *xpath);
static int my_xpath_parse_FilterExpr(MY_XPATH *xpath);
static int my_xpath_parse_PathExpr(MY_XPATH *xpath);
static int my_xpath_parse_OrExpr(MY_XPATH *xpath);
static int my_xpath_parse_UnaryExpr(MY_XPATH *xpath);
static int my_xpath_parse_MultiplicativeExpr(MY_XPATH *xpath);
static int my_xpath_parse_AdditiveExpr(MY_XPATH *xpath);
static int my_xpath_parse_RelationalExpr(MY_XPATH *xpath);
static int my_xpath_parse_AndExpr(MY_XPATH *xpath);
static int my_xpath_parse_EqualityExpr(MY_XPATH *xpath);
static int my_xpath_parse_VariableReference(MY_XPATH *xpath);
/*
Scan LocationPath
SYNOPSYS
[1] LocationPath ::= RelativeLocationPath
| AbsoluteLocationPath
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_LocationPath(MY_XPATH *xpath)
{
Item *context= xpath->context;
if (!xpath->context)
xpath->context= xpath->rootelement;
int rc= my_xpath_parse_RelativeLocationPath(xpath) ||
my_xpath_parse_AbsoluteLocationPath(xpath);
xpath->item= xpath->context;
xpath->context= context;
return rc;
}
/*
Scan Absolute Location Path
SYNOPSYS
[2] AbsoluteLocationPath ::= '/' RelativeLocationPath?
| AbbreviatedAbsoluteLocationPath
[10] AbbreviatedAbsoluteLocationPath ::= '//' RelativeLocationPath
We combine these two rules into one rule for better performance:
[2,10] AbsoluteLocationPath ::= '/' RelativeLocationPath?
| '//' RelativeLocationPath
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_AbsoluteLocationPath(MY_XPATH *xpath)
{
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_SLASH))
return 0;
xpath->context= xpath->rootelement;
if (my_xpath_parse_term(xpath, MY_XPATH_LEX_SLASH))
{
xpath->context= new Item_nodeset_func_descendantbyname(xpath->context,
"*", 1,
xpath->pxml, 1);
return my_xpath_parse_RelativeLocationPath(xpath);
}
my_xpath_parse_RelativeLocationPath(xpath);
return (xpath->error == 0);
}
/*
Scan Relative Location Path
SYNOPSYS
For better performance we combine these two rules
[3] RelativeLocationPath ::= Step
| RelativeLocationPath '/' Step
| AbbreviatedRelativeLocationPath
[11] AbbreviatedRelativeLocationPath ::= RelativeLocationPath '//' Step
Into this one:
[3-11] RelativeLocationPath ::= Step
| RelativeLocationPath '/' Step
| RelativeLocationPath '//' Step
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_RelativeLocationPath(MY_XPATH *xpath)
{
if (!my_xpath_parse_Step(xpath))
return 0;
while (my_xpath_parse_term(xpath, MY_XPATH_LEX_SLASH))
{
if (my_xpath_parse_term(xpath, MY_XPATH_LEX_SLASH))
xpath->context= new Item_nodeset_func_descendantbyname(xpath->context,
"*", 1,
xpath->pxml, 1);
if (!my_xpath_parse_Step(xpath))
{
xpath->error= 1;
return 0;
}
}
return 1;
}
/*
Scan non-abbreviated or abbreviated Step
SYNOPSYS
[4] Step ::= AxisSpecifier NodeTest Predicate*
| AbbreviatedStep
[8] Predicate ::= '[' PredicateExpr ']'
RETURN
1 - success
0 - failure
*/
static int
my_xpath_parse_AxisSpecifier_NodeTest_opt_Predicate_list(MY_XPATH *xpath)
{
if (!my_xpath_parse_AxisSpecifier(xpath))
return 0;
if (!my_xpath_parse_NodeTest(xpath))
return 0;
while (my_xpath_parse_term(xpath, MY_XPATH_LEX_LB))
{
Item *prev_context= xpath->context;
String *context_cache;
context_cache= &((Item_nodeset_func*)xpath->context)->context_cache;
xpath->context= new Item_nodeset_context_cache(context_cache, xpath->pxml);
xpath->context_cache= context_cache;
if(!my_xpath_parse_PredicateExpr(xpath))
{
xpath->error= 1;
return 0;
}
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_RB))
{
xpath->error= 1;
return 0;
}
xpath->item= nodeset2bool(xpath, xpath->item);
if (xpath->item->is_bool_func())
{
xpath->context= new Item_nodeset_func_predicate(prev_context,
xpath->item,
xpath->pxml);
}
else
{
xpath->context= new Item_nodeset_func_elementbyindex(prev_context,
xpath->item,
xpath->pxml);
}
}
return 1;
}
static int my_xpath_parse_Step(MY_XPATH *xpath)
{
return
my_xpath_parse_AxisSpecifier_NodeTest_opt_Predicate_list(xpath) ||
my_xpath_parse_AbbreviatedStep(xpath);
}
/*
Scan Abbreviated Axis Specifier
SYNOPSYS
[5] AxisSpecifier ::= AxisName '::'
| AbbreviatedAxisSpecifier
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_AbbreviatedAxisSpecifier(MY_XPATH *xpath)
{
if (my_xpath_parse_term(xpath, MY_XPATH_LEX_AT))
xpath->axis= MY_XPATH_AXIS_ATTRIBUTE;
else
xpath->axis= MY_XPATH_AXIS_CHILD;
return 1;
}
/*
Scan non-abbreviated axis specifier
SYNOPSYS
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_AxisName_colon_colon(MY_XPATH *xpath)
{
return my_xpath_parse_AxisName(xpath) &&
my_xpath_parse_term(xpath, MY_XPATH_LEX_COLON) &&
my_xpath_parse_term(xpath, MY_XPATH_LEX_COLON);
}
/*
Scan Abbreviated AxisSpecifier
SYNOPSYS
[13] AbbreviatedAxisSpecifier ::= '@'?
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_AxisSpecifier(MY_XPATH *xpath)
{
return my_xpath_parse_AxisName_colon_colon(xpath) ||
my_xpath_parse_AbbreviatedAxisSpecifier(xpath);
}
/*
Scan NodeType followed by parens
SYNOPSYS
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_NodeTest_lp_rp(MY_XPATH *xpath)
{
return my_xpath_parse_term(xpath, MY_XPATH_LEX_NODETYPE) &&
my_xpath_parse_term(xpath, MY_XPATH_LEX_LP) &&
my_xpath_parse_term(xpath, MY_XPATH_LEX_RP);
}
/*
Scan NodeTest
SYNOPSYS
[7] NodeTest ::= NameTest
| NodeType '(' ')'
| 'processing-instruction' '(' Literal ')'
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_NodeTest(MY_XPATH *xpath)
{
return my_xpath_parse_NameTest(xpath) ||
my_xpath_parse_NodeTest_lp_rp(xpath);
}
/*
Scan Abbreviated Step
SYNOPSYS
[12] AbbreviatedStep ::= '.' | '..'
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_AbbreviatedStep(MY_XPATH *xpath)
{
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_DOT))
return 0;
if (my_xpath_parse_term(xpath, MY_XPATH_LEX_DOT))
xpath->context= new Item_nodeset_func_parentbyname(xpath->context, "*", 1,
xpath->pxml);
return 1;
}
/*
Scan Primary Expression
SYNOPSYS
[15] PrimaryExpr ::= VariableReference
| '(' Expr ')'
| Literal
| Number
| FunctionCall
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_lp_Expr_rp(MY_XPATH *xpath)
{
return my_xpath_parse_term(xpath, MY_XPATH_LEX_LP) &&
my_xpath_parse_Expr(xpath) &&
my_xpath_parse_term(xpath, MY_XPATH_LEX_RP);
}
static int my_xpath_parse_PrimaryExpr_literal(MY_XPATH *xpath)
{
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_STRING))
return 0;
xpath->item= new Item_string(xpath->prevtok.beg + 1,
xpath->prevtok.end - xpath->prevtok.beg - 2,
xpath->cs);
return 1;
}
static int my_xpath_parse_PrimaryExpr(MY_XPATH *xpath)
{
return
my_xpath_parse_lp_Expr_rp(xpath) ||
my_xpath_parse_VariableReference(xpath) ||
my_xpath_parse_PrimaryExpr_literal(xpath) ||
my_xpath_parse_Number(xpath) ||
my_xpath_parse_FunctionCall(xpath);
}
/*
Scan Function Call
SYNOPSYS
[16] FunctionCall ::= FunctionName '(' ( Argument ( ',' Argument )* )? ')'
[17] Argument ::= Expr
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_FunctionCall(MY_XPATH *xpath)
{
Item *args[256];
uint nargs;
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_FUNC))
return 0;
MY_XPATH_FUNC *func= xpath->func;
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_LP))
return 0;
for (nargs= 0 ; nargs < func->maxargs; )
{
if (!my_xpath_parse_Expr(xpath))
{
if (nargs < func->minargs)
return 0;
goto right_paren;
}
args[nargs++]= xpath->item;
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_COMMA))
{
if (nargs < func->minargs)
return 0;
else
break;
}
}
right_paren:
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_RP))
return 0;
return ((xpath->item= func->create(xpath, args, nargs))) ? 1 : 0;
}
/*
Scan Union Expression
SYNOPSYS
[18] UnionExpr ::= PathExpr
| UnionExpr '|' PathExpr
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_UnionExpr(MY_XPATH *xpath)
{
if (!my_xpath_parse_PathExpr(xpath))
return 0;
while (my_xpath_parse_term(xpath, MY_XPATH_LEX_VLINE))
{
Item *prev= xpath->item;
if (prev->type() != Item::XPATH_NODESET)
return 0;
if (!my_xpath_parse_PathExpr(xpath)
|| xpath->item->type() != Item::XPATH_NODESET)
{
xpath->error= 1;
return 0;
}
xpath->item= new Item_nodeset_func_union(prev, xpath->item, xpath->pxml);
}
return 1;
}
/*
Scan Path Expression
SYNOPSYS
[19] PathExpr ::= LocationPath
| FilterExpr
| FilterExpr '/' RelativeLocationPath
| FilterExpr '//' RelativeLocationPath
RETURN
1 - success
0 - failure
*/
static int
my_xpath_parse_FilterExpr_opt_slashes_RelativeLocationPath(MY_XPATH *xpath)
{
Item *context= xpath->context;
int rc;
if (!my_xpath_parse_FilterExpr(xpath))
return 0;
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_SLASH))
return 1;
if (xpath->item->type() != Item::XPATH_NODESET)
{
xpath->lasttok= xpath->prevtok;
xpath->error= 1;
return 0;
}
/*
The context for the next relative path is the nodeset
returned by FilterExpr
*/
xpath->context= xpath->item;
/* treat double slash (//) as /descendant-or-self::node()/ */
if (my_xpath_parse_term(xpath, MY_XPATH_LEX_SLASH))
xpath->context= new Item_nodeset_func_descendantbyname(xpath->context,
"*", 1, xpath->pxml, 1);
rc= my_xpath_parse_RelativeLocationPath(xpath);
/* push back the context and restore the item */
xpath->item= xpath->context;
xpath->context= context;
return rc;
}
static int my_xpath_parse_PathExpr(MY_XPATH *xpath)
{
return my_xpath_parse_LocationPath(xpath) ||
my_xpath_parse_FilterExpr_opt_slashes_RelativeLocationPath(xpath);
}
/*
Scan Filter Expression
SYNOPSYS
[20] FilterExpr ::= PrimaryExpr
| FilterExpr Predicate
or in other words:
[20] FilterExpr ::= PrimaryExpr Predicate*
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_FilterExpr(MY_XPATH *xpath)
{
return my_xpath_parse_PrimaryExpr(xpath);
}
/*
Scan Or Expression
SYNOPSYS
[21] OrExpr ::= AndExpr
| OrExpr 'or' AndExpr
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_OrExpr(MY_XPATH *xpath)
{
if (!my_xpath_parse_AndExpr(xpath))
return 0;
while (my_xpath_parse_term(xpath, MY_XPATH_LEX_OR))
{
Item *prev= xpath->item;
if (!my_xpath_parse_AndExpr(xpath))
{
xpath->error= 1;
return 0;
}
xpath->item= new Item_cond_or(nodeset2bool(xpath, prev),
nodeset2bool(xpath, xpath->item));
}
return 1;
}
/*
Scan And Expression
SYNOPSYS
[22] AndExpr ::= EqualityExpr
| AndExpr 'and' EqualityExpr
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_AndExpr(MY_XPATH *xpath)
{
if (!my_xpath_parse_EqualityExpr(xpath))
return 0;
while (my_xpath_parse_term(xpath, MY_XPATH_LEX_AND))
{
Item *prev= xpath->item;
if (!my_xpath_parse_EqualityExpr(xpath))
{
xpath->error= 1;
return 0;
}
xpath->item= new Item_cond_and(nodeset2bool(xpath,prev),
nodeset2bool(xpath,xpath->item));
}
return 1;
}
/*
Scan Equality Expression
SYNOPSYS
[23] EqualityExpr ::= RelationalExpr
| EqualityExpr '=' RelationalExpr
| EqualityExpr '!=' RelationalExpr
or in other words:
[23] EqualityExpr ::= RelationalExpr ( EqualityOperator EqualityExpr )*
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_ne(MY_XPATH *xpath)
{
MY_XPATH_LEX prevtok= xpath->prevtok;
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_EXCL))
return 0;
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_EQ))
{
/* Unget the exclamation mark */
xpath->lasttok= xpath->prevtok;
xpath->prevtok= prevtok;
return 0;
}
return 1;
}
static int my_xpath_parse_EqualityOperator(MY_XPATH *xpath)
{
if (my_xpath_parse_ne(xpath))
{
xpath->extra= '!';
return 1;
}
if (my_xpath_parse_term(xpath, MY_XPATH_LEX_EQ))
{
xpath->extra= '=';
return 1;
}
return 0;
}
static int my_xpath_parse_EqualityExpr(MY_XPATH *xpath)
{
MY_XPATH_LEX operator_context;
if (!my_xpath_parse_RelationalExpr(xpath))
return 0;
operator_context= xpath->lasttok;
while (my_xpath_parse_EqualityOperator(xpath))
{
Item *prev= xpath->item;
int oper= xpath->extra;
if (!my_xpath_parse_RelationalExpr(xpath))
{
xpath->error= 1;
return 0;
}
if (!(xpath->item= create_comparator(xpath, oper, &operator_context,
prev, xpath->item)))
return 0;
operator_context= xpath->lasttok;
}
return 1;
}
/*
Scan Relational Expression
SYNOPSYS
[24] RelationalExpr ::= AdditiveExpr
| RelationalExpr '<' AdditiveExpr
| RelationalExpr '>' AdditiveExpr
| RelationalExpr '<=' AdditiveExpr
| RelationalExpr '>=' AdditiveExpr
or in other words:
[24] RelationalExpr ::= AdditiveExpr (RelationalOperator RelationalExpr)*
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_RelationalOperator(MY_XPATH *xpath)
{
if (my_xpath_parse_term(xpath, MY_XPATH_LEX_LESS))
{
xpath->extra= my_xpath_parse_term(xpath, MY_XPATH_LEX_EQ) ?
MY_XPATH_LEX_LE : MY_XPATH_LEX_LESS;
return 1;
}
else if (my_xpath_parse_term(xpath, MY_XPATH_LEX_GREATER))
{
xpath->extra= my_xpath_parse_term(xpath, MY_XPATH_LEX_EQ) ?
MY_XPATH_LEX_GE : MY_XPATH_LEX_GREATER;
return 1;
}
return 0;
}
static int my_xpath_parse_RelationalExpr(MY_XPATH *xpath)
{
MY_XPATH_LEX operator_context;
if (!my_xpath_parse_AdditiveExpr(xpath))
return 0;
operator_context= xpath->lasttok;
while (my_xpath_parse_RelationalOperator(xpath))
{
Item *prev= xpath->item;
int oper= xpath->extra;
if (!my_xpath_parse_AdditiveExpr(xpath))
{
xpath->error= 1;
return 0;
}
if (!(xpath->item= create_comparator(xpath, oper, &operator_context,
prev, xpath->item)))
return 0;
operator_context= xpath->lasttok;
}
return 1;
}
/*
Scan Additive Expression
SYNOPSYS
[25] AdditiveExpr ::= MultiplicativeExpr
| AdditiveExpr '+' MultiplicativeExpr
| AdditiveExpr '-' MultiplicativeExpr
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_AdditiveOperator(MY_XPATH *xpath)
{
return my_xpath_parse_term(xpath, MY_XPATH_LEX_PLUS) ||
my_xpath_parse_term(xpath, MY_XPATH_LEX_MINUS);
}
static int my_xpath_parse_AdditiveExpr(MY_XPATH *xpath)
{
if (!my_xpath_parse_MultiplicativeExpr(xpath))
return 0;
while (my_xpath_parse_AdditiveOperator(xpath))
{
int oper= xpath->prevtok.term;
Item *prev= xpath->item;
if (!my_xpath_parse_MultiplicativeExpr(xpath))
{
xpath->error= 1;
return 0;
}
if (oper == MY_XPATH_LEX_PLUS)
xpath->item= new Item_func_plus(prev, xpath->item);
else
xpath->item= new Item_func_minus(prev, xpath->item);
};
return 1;
}
/*
Scan Multiplicative Expression
SYNOPSYS
[26] MultiplicativeExpr ::= UnaryExpr
| MultiplicativeExpr MultiplyOperator UnaryExpr
| MultiplicativeExpr 'div' UnaryExpr
| MultiplicativeExpr 'mod' UnaryExpr
or in other words:
[26] MultiplicativeExpr ::= UnaryExpr (MulOper MultiplicativeExpr)*
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_MultiplicativeOperator(MY_XPATH *xpath)
{
return
my_xpath_parse_term(xpath, MY_XPATH_LEX_ASTERISK) ||
my_xpath_parse_term(xpath, MY_XPATH_LEX_DIV) ||
my_xpath_parse_term(xpath, MY_XPATH_LEX_MOD);
}
static int my_xpath_parse_MultiplicativeExpr(MY_XPATH *xpath)
{
if (!my_xpath_parse_UnaryExpr(xpath))
return 0;
while (my_xpath_parse_MultiplicativeOperator(xpath))
{
int oper= xpath->prevtok.term;
Item *prev= xpath->item;
if (!my_xpath_parse_UnaryExpr(xpath))
{
xpath->error= 1;
return 0;
}
switch (oper)
{
case MY_XPATH_LEX_ASTERISK:
xpath->item= new Item_func_mul(prev, xpath->item);
break;
case MY_XPATH_LEX_DIV:
xpath->item= new Item_func_int_div(prev, xpath->item);
break;
case MY_XPATH_LEX_MOD:
xpath->item= new Item_func_mod(prev, xpath->item);
break;
}
}
return 1;
}
/*
Scan Unary Expression
SYNOPSYS
[27] UnaryExpr ::= UnionExpr
| '-' UnaryExpr
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_UnaryExpr(MY_XPATH *xpath)
{
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_MINUS))
return my_xpath_parse_UnionExpr(xpath);
if (!my_xpath_parse_UnaryExpr(xpath))
return 0;
xpath->item= new Item_func_neg(xpath->item);
return 1;
}
/*
Scan Number
SYNOPSYS
[30] Number ::= Digits ('.' Digits?)? | '.' Digits)
or in other words:
[30] Number ::= Digits
| Digits '.'
| Digits '.' Digits
| '.' Digits
Note: the last rule is not supported yet,
as it is in conflict with abbreviated step.
1 + .123 does not work,
1 + 0.123 does.
Perhaps it is better to move this code into lex analizer.
RETURN
1 - success
0 - failure
*/
static int my_xpath_parse_Number(MY_XPATH *xpath)
{
const char *beg;
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_DIGITS))
return 0;
beg= xpath->prevtok.beg;
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_DOT))
{
xpath->item= new Item_int(xpath->prevtok.beg,
xpath->prevtok.end - xpath->prevtok.beg);
return 1;
}
my_xpath_parse_term(xpath, MY_XPATH_LEX_DIGITS);
xpath->item= new Item_float(beg, xpath->prevtok.end - beg);
return 1;
}
/*
Scan NCName.
SYNOPSYS
The keywords AND, OR, MOD, DIV are valid identitiers
when they are in identifier context:
SELECT
ExtractValue('<and><or><mod><div>VALUE</div></mod></or></and>',
'/and/or/mod/div')
-> VALUE
RETURN
1 - success
0 - failure
*/
static int
my_xpath_parse_NCName(MY_XPATH *xpath)
{
return
my_xpath_parse_term(xpath, MY_XPATH_LEX_IDENT) ||
my_xpath_parse_term(xpath, MY_XPATH_LEX_AND) ||
my_xpath_parse_term(xpath, MY_XPATH_LEX_OR) ||
my_xpath_parse_term(xpath, MY_XPATH_LEX_MOD) ||
my_xpath_parse_term(xpath, MY_XPATH_LEX_DIV) ? 1 : 0;
}
/*
QName grammar can be found in a separate document
http://www.w3.org/TR/REC-xml-names/#NT-QName
[6] QName ::= (Prefix ':')? LocalPart
[7] Prefix ::= NCName
[8] LocalPart ::= NCName
*/
static int
my_xpath_parse_QName(MY_XPATH *xpath)
{
const char *beg;
if (!my_xpath_parse_NCName(xpath))
return 0;
beg= xpath->prevtok.beg;
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_COLON))
return 1; /* Non qualified name */
if (!my_xpath_parse_NCName(xpath))
return 0;
xpath->prevtok.beg= beg;
return 1;
}
/**
Scan Variable reference
@details Implements parsing of two syntax structures:
1. Standard XPath syntax [36], for SP variables:
VariableReference ::= '$' QName
Finds a SP variable with the given name.
If outside of a SP context, or variable with
the given name doesn't exists, then error is returned.
2. Non-standard syntax - MySQL extension for user variables:
VariableReference ::= '$' '@' QName
Item, corresponding to the variable, is returned
in xpath->item in both cases.
@param xpath pointer to XPath structure
@return Operation status
@retval 1 Success
@retval 0 Failure
*/
static int
my_xpath_parse_VariableReference(MY_XPATH *xpath)
{
LEX_STRING name;
int user_var;
const char *dollar_pos;
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_DOLLAR) ||
(!(dollar_pos= xpath->prevtok.beg)) ||
(!((user_var= my_xpath_parse_term(xpath, MY_XPATH_LEX_AT) &&
my_xpath_parse_term(xpath, MY_XPATH_LEX_IDENT))) &&
!my_xpath_parse_term(xpath, MY_XPATH_LEX_IDENT)))
return 0;
name.length= xpath->prevtok.end - xpath->prevtok.beg;
name.str= (char*) xpath->prevtok.beg;
if (user_var)
xpath->item= new Item_func_get_user_var(name);
else
{
sp_variable_t *spv;
sp_pcontext *spc;
LEX *lex;
if ((lex= current_thd->lex) &&
(spc= lex->spcont) &&
(spv= spc->find_variable(&name)))
{
Item_splocal *splocal= new Item_splocal(name, spv->offset, spv->type, 0);
#ifndef DBUG_OFF
if (splocal)
splocal->m_sp= lex->sphead;
#endif
xpath->item= (Item*) splocal;
}
else
{
xpath->item= NULL;
DBUG_ASSERT(xpath->query.end > dollar_pos);
uint len= xpath->query.end - dollar_pos;
set_if_smaller(len, 32);
my_printf_error(ER_UNKNOWN_ERROR, "Unknown XPATH variable at: '%.*s'",
MYF(0), len, dollar_pos);
}
}
return xpath->item ? 1 : 0;
}
/*
Scan Name Test
SYNOPSYS
[37] NameTest ::= '*'
| NCName ':' '*'
| QName
RETURN
1 - success
0 - failure
*/
static int
my_xpath_parse_NodeTest_QName(MY_XPATH *xpath)
{
if (!my_xpath_parse_QName(xpath))
return 0;
DBUG_ASSERT(xpath->context);
uint len= xpath->prevtok.end - xpath->prevtok.beg;
xpath->context= nametestfunc(xpath, xpath->axis, xpath->context,
xpath->prevtok.beg, len);
return 1;
}
static int
my_xpath_parse_NodeTest_asterisk(MY_XPATH *xpath)
{
if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_ASTERISK))
return 0;
DBUG_ASSERT(xpath->context);
xpath->context= nametestfunc(xpath, xpath->axis, xpath->context, "*", 1);
return 1;
}
static int
my_xpath_parse_NameTest(MY_XPATH *xpath)
{
return my_xpath_parse_NodeTest_asterisk(xpath) ||
my_xpath_parse_NodeTest_QName(xpath);
}
/*
Scan an XPath expression
SYNOPSYS
Scan xpath expression.
The expression is returned in xpath->expr.
RETURN
1 - success
0 - failure
*/
static int
my_xpath_parse(MY_XPATH *xpath, const char *str, const char *strend)
{
my_xpath_lex_init(&xpath->query, str, strend);
my_xpath_lex_init(&xpath->prevtok, str, strend);
my_xpath_lex_scan(xpath, &xpath->lasttok, str, strend);
xpath->rootelement= new Item_nodeset_func_rootelement(xpath->pxml);
return
my_xpath_parse_Expr(xpath) &&
my_xpath_parse_term(xpath, MY_XPATH_LEX_EOF);
}
void Item_xml_str_func::fix_length_and_dec()
{
String *xp, tmp;
MY_XPATH xpath;
int rc;
status_var_increment(current_thd->status_var.feature_xml);
nodeset_func= 0;
if (agg_arg_charsets_for_comparison(collation, args, arg_count))
return;
if (collation.collation->mbminlen > 1)
{
/* UCS2 is not supported */
my_printf_error(ER_UNKNOWN_ERROR,
"Character set '%s' is not supported by XPATH",
MYF(0), collation.collation->csname);
return;
}
if (!args[1]->const_item())
{
my_printf_error(ER_UNKNOWN_ERROR,
"Only constant XPATH queries are supported", MYF(0));
return;
}
if (!(xp= args[1]->val_str(&tmp)))
return;
my_xpath_init(&xpath);
xpath.cs= collation.collation;
xpath.debug= 0;
xpath.pxml= &pxml;
pxml.set_charset(collation.collation);
rc= my_xpath_parse(&xpath, xp->ptr(), xp->ptr() + xp->length());
if (!rc)
{
uint clen= xpath.query.end - xpath.lasttok.beg;
set_if_smaller(clen, 32);
my_printf_error(ER_UNKNOWN_ERROR, "XPATH syntax error: '%.*s'",
MYF(0), clen, xpath.lasttok.beg);
return;
}
nodeset_func= xpath.item;
if (nodeset_func)
nodeset_func->fix_fields(current_thd, &nodeset_func);
max_length= MAX_BLOB_WIDTH;
}
#define MAX_LEVEL 256
typedef struct
{
uint level;
String *pxml; // parsed XML
uint pos[MAX_LEVEL]; // Tag position stack
uint parent; // Offset of the parent of the current node
} MY_XML_USER_DATA;
static bool
append_node(String *str, MY_XML_NODE *node)
{
/*
If "str" doesn't have space for a new node,
it will allocate two times more space that it has had so far.
(2*len+512) is a heuristic value,
which gave the best performance during tests.
The ideas behind this formula are:
- It allows to have a very small number of reallocs:
about 10 reallocs on a 1Mb-long XML value.
- At the same time, it avoids excessive memory use.
*/
if (str->reserve(sizeof(MY_XML_NODE), 2 * str->length() + 512))
return TRUE;
str->q_append((const char*) node, sizeof(MY_XML_NODE));
return FALSE;
}
/*
Process tag beginning
SYNOPSYS
A call-back function executed when XML parser
is entering a tag or an attribue.
Appends the new node into data->pxml.
Increments data->level.
RETURN
Currently only MY_XML_OK
*/
extern "C" int xml_enter(MY_XML_PARSER *st,const char *attr, size_t len);
int xml_enter(MY_XML_PARSER *st,const char *attr, size_t len)
{
MY_XML_USER_DATA *data= (MY_XML_USER_DATA*)st->user_data;
uint numnodes= data->pxml->length() / sizeof(MY_XML_NODE);
MY_XML_NODE node;
node.parent= data->parent; // Set parent for the new node to old parent
data->parent= numnodes; // Remember current node as new parent
DBUG_ASSERT(data->level <= MAX_LEVEL);
data->pos[data->level]= numnodes;
if (data->level < MAX_LEVEL)
node.level= data->level++;
else
return MY_XML_ERROR;
node.type= st->current_node_type; // TAG or ATTR
node.beg= attr;
node.end= attr + len;
return append_node(data->pxml, &node) ? MY_XML_ERROR : MY_XML_OK;
}
/*
Process text node
SYNOPSYS
A call-back function executed when XML parser
is entering into a tag or an attribue textual value.
The value is appended into data->pxml.
RETURN
Currently only MY_XML_OK
*/
extern "C" int xml_value(MY_XML_PARSER *st,const char *attr, size_t len);
int xml_value(MY_XML_PARSER *st,const char *attr, size_t len)
{
MY_XML_USER_DATA *data= (MY_XML_USER_DATA*)st->user_data;
MY_XML_NODE node;
node.parent= data->parent; // Set parent for the new text node to old parent
node.level= data->level;
node.type= MY_XML_NODE_TEXT;
node.beg= attr;
node.end= attr + len;
return append_node(data->pxml, &node) ? MY_XML_ERROR : MY_XML_OK;
}
/*
Leave a tag or an attribute
SYNOPSYS
A call-back function executed when XML parser
is leaving a tag or an attribue.
Decrements data->level.
RETURN
Currently only MY_XML_OK
*/
extern "C" int xml_leave(MY_XML_PARSER *st,const char *attr, size_t len);
int xml_leave(MY_XML_PARSER *st,const char *attr, size_t len)
{
MY_XML_USER_DATA *data= (MY_XML_USER_DATA*)st->user_data;
DBUG_ASSERT(data->level > 0);
data->level--;
MY_XML_NODE *nodes= (MY_XML_NODE*) data->pxml->ptr();
data->parent= nodes[data->parent].parent;
nodes+= data->pos[data->level];
nodes->tagend= st->cur;
return MY_XML_OK;
}
/*
Parse raw XML
SYNOPSYS
RETURN
Currently pointer to parsed XML on success
0 on parse error
*/
String *Item_xml_str_func::parse_xml(String *raw_xml, String *parsed_xml_buf)
{
MY_XML_PARSER p;
MY_XML_USER_DATA user_data;
int rc;
parsed_xml_buf->length(0);
/* Prepare XML parser */
my_xml_parser_create(&p);
p.flags= MY_XML_FLAG_RELATIVE_NAMES | MY_XML_FLAG_SKIP_TEXT_NORMALIZATION;
user_data.level= 0;
user_data.pxml= parsed_xml_buf;
user_data.parent= 0;
my_xml_set_enter_handler(&p, xml_enter);
my_xml_set_value_handler(&p, xml_value);
my_xml_set_leave_handler(&p, xml_leave);
my_xml_set_user_data(&p, (void*) &user_data);
/* Add root node */
p.current_node_type= MY_XML_NODE_TAG;
xml_enter(&p, raw_xml->ptr(), 0);
/* Execute XML parser */
if ((rc= my_xml_parse(&p, raw_xml->ptr(), raw_xml->length())) != MY_XML_OK)
{
char buf[128];
my_snprintf(buf, sizeof(buf)-1, "parse error at line %d pos %lu: %s",
my_xml_error_lineno(&p) + 1,
(ulong) my_xml_error_pos(&p) + 1,
my_xml_error_string(&p));
push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
ER_WRONG_VALUE,
ER(ER_WRONG_VALUE), "XML", buf);
}
my_xml_parser_free(&p);
return rc == MY_XML_OK ? parsed_xml_buf : 0;
}
String *Item_func_xml_extractvalue::val_str(String *str)
{
String *res;
null_value= 0;
if (!nodeset_func ||
!(res= args[0]->val_str(str)) ||
!parse_xml(res, &pxml) ||
!(res= nodeset_func->val_str(&tmp_value)))
{
null_value= 1;
return 0;
}
return res;
}
String *Item_func_xml_update::val_str(String *str)
{
String *res, *nodeset, *rep;
null_value= 0;
if (!nodeset_func ||
!(res= args[0]->val_str(str)) ||
!(rep= args[2]->val_str(&tmp_value3)) ||
!parse_xml(res, &pxml) ||
!(nodeset= nodeset_func->val_nodeset(&tmp_value2)))
{
null_value= 1;
return 0;
}
MY_XML_NODE *nodebeg= (MY_XML_NODE*) pxml.ptr();
MY_XPATH_FLT *fltbeg= (MY_XPATH_FLT*) nodeset->ptr();
MY_XPATH_FLT *fltend= (MY_XPATH_FLT*) (nodeset->ptr() + nodeset->length());
/* Allow replacing of one tag only */
if (fltend - fltbeg != 1)
{
/* TODO: perhaps add a warning that more than one tag selected */
return res;
}
nodebeg+= fltbeg->num;
if (!nodebeg->level)
{
/*
Root element, without NameTest:
UpdateXML(xml, '/', 'replacement');
Just return the replacement string.
*/
return rep;
}
tmp_value.length(0);
tmp_value.set_charset(collation.collation);
uint offs= nodebeg->type == MY_XML_NODE_TAG ? 1 : 0;
tmp_value.append(res->ptr(), nodebeg->beg - res->ptr() - offs);
tmp_value.append(rep->ptr(), rep->length());
const char *end= nodebeg->tagend + offs;
tmp_value.append(end, res->ptr() + res->length() - end);
return &tmp_value;
}
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