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Diffstat (limited to '')
| -rw-r--r-- | sql/item_xmlfunc.cc | 3072 |
1 files changed, 3072 insertions, 0 deletions
diff --git a/sql/item_xmlfunc.cc b/sql/item_xmlfunc.cc new file mode 100644 index 00000000..6e863b1f --- /dev/null +++ b/sql/item_xmlfunc.cc @@ -0,0 +1,3072 @@ +/* Copyright (c) 2005, 2019, Oracle and/or its affiliates. + Copyright (c) 2009, 2020, MariaDB + + 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 02110-1335 USA */ + +#include "mariadb.h" +#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 nodeset_to_nodeset_comparator + 2. add lacking functions: + - name() + - lang() + - string() + - id() + - translate() + - local-name() + - starts-with() + - namespace-uri() + - substring-after() + - normalize-space() + - substring-before() + 3. 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 analyzer 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; + + +/* 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 +{ + THD *thd; + 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 */ + Native *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; + + +static Type_handler_long_blob type_handler_xpath_nodeset; + + +/* + Common features of the functions returning a node set. +*/ +class Item_nodeset_func :public Item_str_func +{ +protected: + NativeNodesetBuffer tmp_native_value, tmp2_native_value; + MY_XPATH_FLT *fltbeg, *fltend; + MY_XML_NODE *nodebeg, *nodeend; + uint numnodes; +public: + String *pxml; + NativeNodesetBuffer context_cache; + Item_nodeset_func(THD *thd, String *pxml_arg): + Item_str_func(thd), pxml(pxml_arg) {} + Item_nodeset_func(THD *thd, Item *a, String *pxml_arg): + Item_str_func(thd, a), pxml(pxml_arg) {} + Item_nodeset_func(THD *thd, Item *a, Item *b, String *pxml_arg): + Item_str_func(thd, a, b), pxml(pxml_arg) {} + Item_nodeset_func(THD *thd, Item *a, Item *b, Item *c, String *pxml_arg): + Item_str_func(thd, a, b, c), pxml(pxml_arg) {} + void prepare_nodes() + { + nodebeg= (MY_XML_NODE*) pxml->ptr(); + nodeend= (MY_XML_NODE*) (pxml->ptr() + pxml->length()); + numnodes= (uint)(nodeend - nodebeg); + } + void prepare(THD *thd, Native *nodeset) + { + prepare_nodes(); + args[0]->val_native(thd, &tmp_native_value); + fltbeg= (MY_XPATH_FLT*) tmp_native_value.ptr(); + fltend= (MY_XPATH_FLT*) tmp_native_value.end(); + nodeset->length(0); + } + const Type_handler *type_handler() const + { + return &type_handler_xpath_nodeset; + } + const Type_handler *fixed_type_handler() const + { + return &type_handler_xpath_nodeset; + } + Field *create_tmp_field_ex(MEM_ROOT *root, TABLE *table, Tmp_field_src *src, + const Tmp_field_param *param) + { + DBUG_ASSERT(0); + return NULL; + } + String *val_str(String *str) + { + prepare_nodes(); + val_native(current_thd, &tmp2_native_value); + fltbeg= (MY_XPATH_FLT*) tmp2_native_value.ptr(); + fltend= (MY_XPATH_FLT*) tmp2_native_value.end(); + 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; + } + bool fix_length_and_dec() + { + max_length= MAX_BLOB_WIDTH; + collation.collation= pxml->charset(); + // To avoid premature evaluation, mark all nodeset functions as non-const. + used_tables_cache= RAND_TABLE_BIT; + const_item_cache= false; + return FALSE; + } + const char *func_name() const { return "nodeset"; } + bool check_vcol_func_processor(void *arg) + { + return mark_unsupported_function(func_name(), arg, VCOL_IMPOSSIBLE); + } + +}; + + +/* Returns an XML root */ +class Item_nodeset_func_rootelement :public Item_nodeset_func +{ +public: + Item_nodeset_func_rootelement(THD *thd, String *pxml): + Item_nodeset_func(thd, pxml) {} + const char *func_name() const { return "xpath_rootelement"; } + bool val_native(THD *thd, Native *nodeset); + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_func_rootelement>(thd, this); } +}; + + +/* Returns a Union of two node sets */ +class Item_nodeset_func_union :public Item_nodeset_func +{ +public: + Item_nodeset_func_union(THD *thd, Item *a, Item *b, String *pxml): + Item_nodeset_func(thd, a, b, pxml) {} + const char *func_name() const { return "xpath_union"; } + bool val_native(THD *thd, Native *nodeset); + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_func_union>(thd, this); } +}; + + +/* 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(THD *thd, Item *a, const char *n_arg, uint l_arg, + String *pxml): + Item_nodeset_func(thd, 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(THD *thd, Item *a, const char *n_arg, uint l_arg, + String *pxml): + Item_nodeset_func_axisbyname(thd, a, n_arg, l_arg, pxml) {} + const char *func_name() const { return "xpath_selfbyname"; } + bool val_native(THD *thd, Native *nodeset); + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_func_selfbyname>(thd, this); } +}; + + +/* Returns children */ +class Item_nodeset_func_childbyname: public Item_nodeset_func_axisbyname +{ +public: + Item_nodeset_func_childbyname(THD *thd, Item *a, const char *n_arg, uint l_arg, + String *pxml): + Item_nodeset_func_axisbyname(thd, a, n_arg, l_arg, pxml) {} + const char *func_name() const { return "xpath_childbyname"; } + bool val_native(THD *thd, Native *nodeset); + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_func_childbyname>(thd, this); } +}; + + +/* Returns descendants */ +class Item_nodeset_func_descendantbyname: public Item_nodeset_func_axisbyname +{ + bool need_self; +public: + Item_nodeset_func_descendantbyname(THD *thd, Item *a, const char *n_arg, uint l_arg, + String *pxml, bool need_self_arg): + Item_nodeset_func_axisbyname(thd, a, n_arg, l_arg, pxml), + need_self(need_self_arg) {} + const char *func_name() const { return "xpath_descendantbyname"; } + bool val_native(THD *thd, Native *nodeset); + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_func_descendantbyname>(thd, this); } +}; + + +/* Returns ancestors */ +class Item_nodeset_func_ancestorbyname: public Item_nodeset_func_axisbyname +{ + bool need_self; +public: + Item_nodeset_func_ancestorbyname(THD *thd, Item *a, const char *n_arg, uint l_arg, + String *pxml, bool need_self_arg): + Item_nodeset_func_axisbyname(thd, a, n_arg, l_arg, pxml), + need_self(need_self_arg) {} + const char *func_name() const { return "xpath_ancestorbyname"; } + bool val_native(THD *thd, Native *nodeset); + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_func_ancestorbyname>(thd, this); } +}; + + +/* Returns parents */ +class Item_nodeset_func_parentbyname: public Item_nodeset_func_axisbyname +{ +public: + Item_nodeset_func_parentbyname(THD *thd, Item *a, const char *n_arg, uint l_arg, + String *pxml): + Item_nodeset_func_axisbyname(thd, a, n_arg, l_arg, pxml) {} + const char *func_name() const { return "xpath_parentbyname"; } + bool val_native(THD *thd, Native *nodeset); + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_func_parentbyname>(thd, this); } +}; + + +/* Returns attributes */ +class Item_nodeset_func_attributebyname: public Item_nodeset_func_axisbyname +{ +public: + Item_nodeset_func_attributebyname(THD *thd, Item *a, const char *n_arg, + uint l_arg, String *pxml): + Item_nodeset_func_axisbyname(thd, a, n_arg, l_arg, pxml) {} + const char *func_name() const { return "xpath_attributebyname"; } + bool val_native(THD *thd, Native *nodeset); + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_func_attributebyname>(thd, this); } +}; + + +/* + 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(THD *thd, Item *a, Item *b, String *pxml): + Item_nodeset_func(thd, a, b, pxml) {} + const char *func_name() const { return "xpath_predicate"; } + bool val_native(THD *thd, Native *nodeset); + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_func_predicate>(thd, this); } +}; + + +/* Selects nodes with a given position in context */ +class Item_nodeset_func_elementbyindex :public Item_nodeset_func +{ +public: + Item_nodeset_func_elementbyindex(THD *thd, Item *a, Item *b, String *pxml): + Item_nodeset_func(thd, a, b, pxml) { } + const char *func_name() const { return "xpath_elementbyindex"; } + bool val_native(THD *thd, Native *nodeset); + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_func_elementbyindex>(thd, this); } +}; + + +/* + 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_bool_func +{ + String *pxml; + NativeNodesetBuffer tmp_native_value; +public: + Item_xpath_cast_bool(THD *thd, Item *a, String *pxml_arg): + Item_bool_func(thd, a), pxml(pxml_arg) {} + const char *func_name() const { return "xpath_cast_bool"; } + longlong val_int() + { + if (args[0]->fixed_type_handler() == &type_handler_xpath_nodeset) + { + args[0]->val_native(current_thd, &tmp_native_value); + return tmp_native_value.elements() == 1 ? 1 : 0; + } + return args[0]->val_real() ? 1 : 0; + } + Item *get_copy(THD *thd) + { return get_item_copy<Item_xpath_cast_bool>(thd, this); } +}; + + +/* + Converts its argument into a number +*/ +class Item_xpath_cast_number :public Item_real_func +{ +public: + Item_xpath_cast_number(THD *thd, Item *a): Item_real_func(thd, a) {} + const char *func_name() const { return "xpath_cast_number"; } + virtual double val_real() { return args[0]->val_real(); } + Item *get_copy(THD *thd) + { return get_item_copy<Item_xpath_cast_number>(thd, this); } +}; + + +/* + Context cache, for predicate +*/ +class Item_nodeset_context_cache :public Item_nodeset_func +{ +public: + Native *native_cache; + Item_nodeset_context_cache(THD *thd, Native *native_arg, String *pxml): + Item_nodeset_func(thd, pxml), native_cache(native_arg) { } + bool val_native(THD *thd, Native *nodeset) + { + return nodeset->copy(*native_cache); + } + bool fix_length_and_dec() { max_length= MAX_BLOB_WIDTH;; return FALSE; } + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_context_cache>(thd, this); } +}; + + +class Item_func_xpath_position :public Item_long_func +{ + String *pxml; + NativeNodesetBuffer tmp_native_value; +public: + Item_func_xpath_position(THD *thd, Item *a, String *p): + Item_long_func(thd, a), pxml(p) {} + const char *func_name() const { return "xpath_position"; } + bool fix_length_and_dec() { max_length=10; return FALSE; } + longlong val_int() + { + args[0]->val_native(current_thd, &tmp_native_value); + if (tmp_native_value.elements() == 1) + return tmp_native_value.element(0).pos + 1; + return 0; + } + Item *get_copy(THD *thd) + { return get_item_copy<Item_func_xpath_position>(thd, this); } +}; + + +class Item_func_xpath_count :public Item_long_func +{ + String *pxml; + NativeNodesetBuffer tmp_native_value; +public: + Item_func_xpath_count(THD *thd, Item *a, String *p): + Item_long_func(thd, a), pxml(p) {} + const char *func_name() const { return "xpath_count"; } + bool fix_length_and_dec() { max_length=10; return FALSE; } + longlong val_int() + { + uint predicate_supplied_context_size; + args[0]->val_native(current_thd, &tmp_native_value); + if (tmp_native_value.elements() == 1 && + (predicate_supplied_context_size= tmp_native_value.element(0).size)) + return predicate_supplied_context_size; + return tmp_native_value.elements(); + } + Item *get_copy(THD *thd) + { return get_item_copy<Item_func_xpath_count>(thd, this); } +}; + + +class Item_func_xpath_sum :public Item_real_func +{ + String *pxml; + NativeNodesetBuffer tmp_native_value; +public: + Item_func_xpath_sum(THD *thd, Item *a, String *p): + Item_real_func(thd, a), pxml(p) {} + + const char *func_name() const { return "xpath_sum"; } + double val_real() + { + double sum= 0; + args[0]->val_native(current_thd, &tmp_native_value); + MY_XPATH_FLT *fltbeg= (MY_XPATH_FLT*) tmp_native_value.ptr(); + MY_XPATH_FLT *fltend= (MY_XPATH_FLT*) tmp_native_value.end(); + 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= collation.collation->strntod((char*) node->beg, + node->end - node->beg, &end, &err); + if (!err) + sum+= add; + } + } + } + return sum; + } + Item *get_copy(THD *thd) + { return get_item_copy<Item_func_xpath_sum>(thd, this); } +}; + + +/** + A string whose value may be changed during execution. +*/ +class Item_string_xml_non_const: public Item_string +{ +public: + Item_string_xml_non_const(THD *thd, const char *str, uint length, + CHARSET_INFO *cs): + Item_string(thd, str, length, cs) + { } + bool const_item() const { return false ; } + bool basic_const_item() const { return false; } + void set_value(const char *str, uint length, CHARSET_INFO *cs) + { + str_value.set(str, length, cs); + } + Item *safe_charset_converter(THD *thd, CHARSET_INFO *tocs) + { + /* + Item_string::safe_charset_converter() does not accept non-constants. + Note, conversion is not really needed here anyway. + */ + return this; + } +}; + + +class Item_nodeset_to_const_comparator :public Item_bool_func +{ + String *pxml; + NativeNodesetBuffer tmp_nodeset; +public: + Item_nodeset_to_const_comparator(THD *thd, Item *nodeset, Item *cmpfunc, + String *p): + Item_bool_func(thd, nodeset, cmpfunc), pxml(p) {} + const char *func_name() const { return "xpath_nodeset_to_const_comparator"; } + bool check_vcol_func_processor(void *arg) + { + return mark_unsupported_function(func_name(), arg, VCOL_IMPOSSIBLE); + } + Field *create_tmp_field_ex(MEM_ROOT *root, TABLE *table, Tmp_field_src *src, + const Tmp_field_param *param) + { + DBUG_ASSERT(0); + return NULL; + } + longlong val_int() + { + Item_func *comp= (Item_func*)args[1]; + Item_string_xml_non_const *fake= + (Item_string_xml_non_const*)(comp->arguments()[0]); + args[0]->val_native(current_thd, &tmp_nodeset); + MY_XPATH_FLT *fltbeg= (MY_XPATH_FLT*) tmp_nodeset.ptr(); + MY_XPATH_FLT *fltend= (MY_XPATH_FLT*) tmp_nodeset.end(); + 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->set_value(node->beg, (uint)(node->end - node->beg), + collation.collation); + if (args[1]->val_int()) + return 1; + } + } + } + return 0; + } + Item *get_copy(THD *thd) + { return get_item_copy<Item_nodeset_to_const_comparator>(thd, this); } +}; + + +bool Item_nodeset_func_rootelement::val_native(THD *thd, Native *nodeset) +{ + nodeset->length(0); + return MY_XPATH_FLT(0, 0).append_to(nodeset); +} + + +bool Item_nodeset_func_union::val_native(THD *thd, Native *nodeset) +{ + uint num_nodes= pxml->length() / sizeof(MY_XML_NODE); + NativeNodesetBuffer set0, set1; + args[0]->val_native(thd, &set0); + args[1]->val_native(thd, &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*) set0.ptr(); + fltend= (MY_XPATH_FLT*) set0.end(); + for (flt= fltbeg; flt < fltend; flt++) + both[flt->num]= 1; + + fltbeg= (MY_XPATH_FLT*) set1.ptr(); + fltend= (MY_XPATH_FLT*) set1.end(); + 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]) + MY_XPATH_FLT(i, pos++).append_to(nodeset); + } + return false; +} + + +bool Item_nodeset_func_selfbyname::val_native(THD *thd, Native *nodeset) +{ + prepare(thd, nodeset); + for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++) + { + uint pos= 0; + MY_XML_NODE *self= &nodebeg[flt->num]; + if (validname(self)) + MY_XPATH_FLT(flt->num, pos++).append_to(nodeset); + } + return false; +} + + +bool Item_nodeset_func_childbyname::val_native(THD *thd, Native *nodeset) +{ + prepare(thd, 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)) + MY_XPATH_FLT(j, pos++).append_to(nodeset); + } + } + return false; +} + + +bool Item_nodeset_func_descendantbyname::val_native(THD *thd, Native *nodeset) +{ + prepare(thd, 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)) + MY_XPATH_FLT(flt->num, pos++).append_to(nodeset); + 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)) + MY_XPATH_FLT(j, pos++).append_to(nodeset); + } + } + return false; +} + + +bool Item_nodeset_func_ancestorbyname::val_native(THD *thd, Native *nodeset) +{ + char *active; + String active_str; + prepare(thd, 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]) + MY_XPATH_FLT(j, --pos).append_to(nodeset); + } + return false; +} + + +bool Item_nodeset_func_parentbyname::val_native(THD *thd, Native *nodeset) +{ + char *active; + String active_str; + prepare(thd, 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]) + MY_XPATH_FLT(j, pos++).append_to(nodeset); + } + return false; +} + + +bool Item_nodeset_func_attributebyname::val_native(THD *thd, Native *nodeset) +{ + prepare(thd, 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)) + MY_XPATH_FLT(j, pos++).append_to(nodeset); + } + } + return false; +} + + +bool Item_nodeset_func_predicate::val_native(THD *thd, Native *str) +{ + Item_nodeset_func *nodeset_func= (Item_nodeset_func*) args[0]; + uint pos= 0, size; + prepare(thd, str); + size= (uint)(fltend - fltbeg); + for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++) + { + nodeset_func->context_cache.length(0); + MY_XPATH_FLT(flt->num, flt->pos, size). + append_to(&nodeset_func->context_cache); + if (args[1]->val_int()) + MY_XPATH_FLT(flt->num, pos++).append_to(str); + } + return false; +} + + +bool Item_nodeset_func_elementbyindex::val_native(THD *thd, Native *nodeset) +{ + Item_nodeset_func *nodeset_func= (Item_nodeset_func*) args[0]; + prepare(thd, nodeset); + MY_XPATH_FLT *flt; + uint pos, size= (uint)(fltend - fltbeg); + for (pos= 0, flt= fltbeg; flt < fltend; flt++) + { + nodeset_func->context_cache.length(0); + MY_XPATH_FLT(flt->num, flt->pos, size). + append_to(&nodeset_func->context_cache); + int index= (int) (args[1]->val_int()) - 1; + if (index >= 0 && + (flt->pos == (uint) index || + (args[1]->type_handler()->is_bool_type()))) + MY_XPATH_FLT(flt->num, pos++).append_to(nodeset); + } + return false; +} + + +/* + 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->fixed_type_handler() == &type_handler_xpath_nodeset) + return new (xpath->thd->mem_root) + Item_xpath_cast_bool(xpath->thd, 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(THD *thd, int oper, Item *a, Item *b) +{ + MEM_ROOT *mem_root= thd->mem_root; + switch (oper) + { + case '=': return new (mem_root) Item_func_eq(thd, a, b); + case '!': return new (mem_root) Item_func_ne(thd, a, b); + case MY_XPATH_LEX_GE: return new (mem_root) Item_func_ge(thd, a, b); + case MY_XPATH_LEX_LE: return new (mem_root) Item_func_le(thd, a, b); + case MY_XPATH_LEX_GREATER: return new (mem_root) Item_func_gt(thd, a, b); + case MY_XPATH_LEX_LESS: return new (mem_root) Item_func_lt(thd, 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(THD *thd, int oper, Item *a, Item *b) +{ + MEM_ROOT *mem_root= thd->mem_root; + switch (oper) + { + case '=': return new (mem_root) Item_func_eq(thd, a, b); + case '!': return new (mem_root) Item_func_ne(thd, a, b); + case MY_XPATH_LEX_GE: return new (mem_root) Item_func_le(thd, a, b); + case MY_XPATH_LEX_LE: return new (mem_root) Item_func_ge(thd, a, b); + case MY_XPATH_LEX_GREATER: return new (mem_root) Item_func_lt(thd, a, b); + case MY_XPATH_LEX_LESS: return new (mem_root) Item_func_gt(thd, 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->fixed_type_handler() != &type_handler_xpath_nodeset && + b->fixed_type_handler() != &type_handler_xpath_nodeset) + { + return eq_func(xpath->thd, oper, a, b); // two scalar arguments + } + else if (a->fixed_type_handler() == &type_handler_xpath_nodeset && + b->fixed_type_handler() == &type_handler_xpath_nodeset) + { + uint len= (uint)(xpath->query.end - context->beg); + if (len <= 32) + my_printf_error(ER_UNKNOWN_ERROR, + "XPATH error: " + "comparison of two nodesets is not supported: '%.*s'", + MYF(0), len, context->beg); + else + my_printf_error(ER_UNKNOWN_ERROR, + "XPATH error: " + "comparison of two nodesets is not supported: '%.32T'", + MYF(0), 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_xml_non_const() argument, + which will be filled to the partular value + in a loop through all of the nodes in the node set. + */ + + THD *thd= xpath->thd; + Item_string *fake= (new (thd->mem_root) + Item_string_xml_non_const(thd, "", 0, xpath->cs)); + Item_nodeset_func *nodeset; + Item *scalar, *comp; + if (a->fixed_type_handler() == &type_handler_xpath_nodeset) + { + nodeset= (Item_nodeset_func*) a; + scalar= b; + comp= eq_func(thd, oper, (Item*)fake, scalar); + } + else + { + nodeset= (Item_nodeset_func*) b; + scalar= a; + comp= eq_func_reverse(thd, oper, fake, scalar); + } + return (new (thd->mem_root) + Item_nodeset_to_const_comparator(thd, 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) +{ + THD *thd= xpath->thd; + MEM_ROOT *mem_root= thd->mem_root; + + DBUG_ASSERT(arg != 0); + DBUG_ASSERT(arg->fixed_type_handler() == &type_handler_xpath_nodeset); + DBUG_ASSERT(beg != 0); + DBUG_ASSERT(len > 0); + + Item *res; + switch (type) + { + case MY_XPATH_AXIS_ANCESTOR: + res= new (mem_root) Item_nodeset_func_ancestorbyname(thd, arg, beg, len, + xpath->pxml, 0); + break; + case MY_XPATH_AXIS_ANCESTOR_OR_SELF: + res= new (mem_root) Item_nodeset_func_ancestorbyname(thd, arg, beg, len, + xpath->pxml, 1); + break; + case MY_XPATH_AXIS_PARENT: + res= new (mem_root) Item_nodeset_func_parentbyname(thd, arg, beg, len, + xpath->pxml); + break; + case MY_XPATH_AXIS_DESCENDANT: + res= new (mem_root) Item_nodeset_func_descendantbyname(thd, arg, beg, len, + xpath->pxml, 0); + break; + case MY_XPATH_AXIS_DESCENDANT_OR_SELF: + res= new (mem_root) Item_nodeset_func_descendantbyname(thd, arg, beg, len, + xpath->pxml, 1); + break; + case MY_XPATH_AXIS_ATTRIBUTE: + res= new (mem_root) Item_nodeset_func_attributebyname(thd, arg, beg, len, + xpath->pxml); + break; + case MY_XPATH_AXIS_SELF: + res= new (mem_root) Item_nodeset_func_selfbyname(thd, arg, beg, len, + xpath->pxml); + break; + default: + res= new (mem_root) Item_nodeset_func_childbyname(thd, arg, beg, len, + xpath->pxml); + } + return res; +} + + +/* + Tokens consisting of one character, for faster lexical analyzer. +*/ +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 { | } ~ \200 +*/ + 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 (xpath->thd->mem_root) Item_bool(xpath->thd, "xpath_bool", 1); +} + + +static Item *create_func_false(MY_XPATH *xpath, Item **args, uint nargs) +{ + return new (xpath->thd->mem_root) Item_bool(xpath->thd, "xpath_bool", 0); +} + + +static Item *create_func_not(MY_XPATH *xpath, Item **args, uint nargs) +{ + return new (xpath->thd->mem_root) + Item_func_not(xpath->thd, nodeset2bool(xpath, args[0])); +} + + +static Item *create_func_ceiling(MY_XPATH *xpath, Item **args, uint nargs) +{ + return new (xpath->thd->mem_root) Item_func_ceiling(xpath->thd, args[0]); +} + + +static Item *create_func_floor(MY_XPATH *xpath, Item **args, uint nargs) +{ + return new (xpath->thd->mem_root) Item_func_floor(xpath->thd, args[0]); +} + + +static Item *create_func_bool(MY_XPATH *xpath, Item **args, uint nargs) +{ + return new (xpath->thd->mem_root) + Item_xpath_cast_bool(xpath->thd, args[0], xpath->pxml); +} + + +static Item *create_func_number(MY_XPATH *xpath, Item **args, uint nargs) +{ + return new (xpath->thd->mem_root) + Item_xpath_cast_number(xpath->thd, 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 (xpath->thd->mem_root) + Item_func_char_length(xpath->thd, arg) : 0; +} + + +static Item *create_func_round(MY_XPATH *xpath, Item **args, uint nargs) +{ + return new (xpath->thd->mem_root) + Item_func_round(xpath->thd, args[0], + new (xpath->thd->mem_root) + Item_int(xpath->thd, (char *) "0", 0, 1), 0); +} + + +static Item *create_func_last(MY_XPATH *xpath, Item **args, uint nargs) +{ + return (xpath->context ? + new (xpath->thd->mem_root) + Item_func_xpath_count(xpath->thd, xpath->context, xpath->pxml) : + NULL); +} + + +static Item *create_func_position(MY_XPATH *xpath, Item **args, uint nargs) +{ + return (xpath->context ? + new (xpath->thd->mem_root) + Item_func_xpath_position(xpath->thd, xpath->context, xpath->pxml) : + NULL); +} + + +static Item *create_func_contains(MY_XPATH *xpath, Item **args, uint nargs) +{ + return (new (xpath->thd->mem_root) + Item_xpath_cast_bool(xpath->thd, + new (xpath->thd->mem_root) + Item_func_locate(xpath->thd, args[0], args[1]), + xpath->pxml)); +} + + +static Item *create_func_concat(MY_XPATH *xpath, Item **args, uint nargs) +{ + return new (xpath->thd->mem_root) + Item_func_concat(xpath->thd, args[0], args[1]); +} + + +static Item *create_func_substr(MY_XPATH *xpath, Item **args, uint nargs) +{ + THD *thd= xpath->thd; + if (nargs == 2) + return new (thd->mem_root) Item_func_substr(thd, args[0], args[1]); + return new (thd->mem_root) Item_func_substr(thd, args[0], args[1], args[2]); +} + + +static Item *create_func_count(MY_XPATH *xpath, Item **args, uint nargs) +{ + if (args[0]->fixed_type_handler() != &type_handler_xpath_nodeset) + return 0; + return new (xpath->thd->mem_root) Item_func_xpath_count(xpath->thd, args[0], xpath->pxml); +} + + +static Item *create_func_sum(MY_XPATH *xpath, Item **args, uint nargs) +{ + if (args[0]->fixed_type_handler() != &type_handler_xpath_nodeset) + return 0; + return new (xpath->thd->mem_root) + Item_func_xpath_sum(xpath->thd, 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= (uint)(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 analyzer 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 beginning + 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->ctype(&ctype, + (const uchar*) beg, + (const uchar*) end)) > 0 && + ((ctype & (_MY_L | _MY_U)) || *beg == '_')) + { + // scan until the end of the identifier + for (beg+= length; + (length= xpath->cs->ctype(&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 single "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 (xpath->thd->mem_root) + Item_nodeset_func_descendantbyname(xpath->thd, + 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 (xpath->thd->mem_root) + Item_nodeset_func_descendantbyname(xpath->thd, + 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; + Native *context_cache; + context_cache= &((Item_nodeset_func*)xpath->context)->context_cache; + xpath->context= new (xpath->thd->mem_root) + Item_nodeset_context_cache(xpath->thd, 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); + + const Type_handler *fh; + if ((fh= xpath->item->fixed_type_handler()) && fh->is_bool_type()) + { + xpath->context= new (xpath->thd->mem_root) + Item_nodeset_func_predicate(xpath->thd, prev_context, + xpath->item, + xpath->pxml); + } + else + { + xpath->context= new (xpath->thd->mem_root) + Item_nodeset_func_elementbyindex(xpath->thd, + 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 (xpath->thd->mem_root) + Item_nodeset_func_parentbyname(xpath->thd, + 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 (xpath->thd->mem_root) + Item_string(xpath->thd, xpath->prevtok.beg + 1, + (uint)(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->fixed_type_handler() != &type_handler_xpath_nodeset) + return 0; + + if (!my_xpath_parse_PathExpr(xpath) + || xpath->item->fixed_type_handler() != &type_handler_xpath_nodeset) + { + xpath->error= 1; + return 0; + } + xpath->item= new (xpath->thd->mem_root) + Item_nodeset_func_union(xpath->thd, 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->fixed_type_handler() != &type_handler_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 (xpath->thd->mem_root) + Item_nodeset_func_descendantbyname(xpath->thd, + 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 (xpath->thd->mem_root) + Item_cond_or(xpath->thd, 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 (xpath->thd->mem_root) + Item_cond_and(xpath->thd, 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; + THD *thd= xpath->thd; + + if (!my_xpath_parse_MultiplicativeExpr(xpath)) + { + xpath->error= 1; + return 0; + } + + if (oper == MY_XPATH_LEX_PLUS) + xpath->item= new (thd->mem_root) + Item_func_plus(thd, prev, xpath->item); + else + xpath->item= new (thd->mem_root) + Item_func_minus(thd, 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; + + THD *thd= xpath->thd; + 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 (thd->mem_root) Item_func_mul(thd, prev, xpath->item); + break; + case MY_XPATH_LEX_DIV: + xpath->item= new (thd->mem_root) Item_func_int_div(thd, prev, xpath->item); + break; + case MY_XPATH_LEX_MOD: + xpath->item= new (thd->mem_root) Item_func_mod(thd, 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 (xpath->thd->mem_root) + Item_func_neg(xpath->thd, xpath->item); + return 1; +} + + +/** + A helper class to make a null-terminated string from XPath fragments. + The string is allocated on the THD memory root. +*/ +class XPath_cstring_null_terminated: public LEX_CSTRING +{ +public: + XPath_cstring_null_terminated(THD *thd, const char *str, size_t length) + { + if (thd->make_lex_string(this, str, length)) + static_cast<LEX_CSTRING>(*this)= empty_clex_str; + } +}; + + +/* + 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 analyzer. + + RETURN + 1 - success + 0 - failure +*/ +static int my_xpath_parse_Number(MY_XPATH *xpath) +{ + const char *beg; + THD *thd; + if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_DIGITS)) + return 0; + beg= xpath->prevtok.beg; + thd= xpath->thd; + if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_DOT)) + { + XPath_cstring_null_terminated nr(thd, beg, xpath->prevtok.end - beg); + xpath->item= new (thd->mem_root) Item_int(thd, nr.str, (uint) nr.length); + } + else + { + my_xpath_parse_term(xpath, MY_XPATH_LEX_DIGITS); + XPath_cstring_null_terminated nr(thd, beg, xpath->prevtok.end - beg); + xpath->item= new (thd->mem_root) Item_float(thd, nr.str, (uint) nr.length); + } + 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_CSTRING name; + int user_var; + const char *dollar_pos; + THD *thd= xpath->thd; + 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 (thd->mem_root) Item_func_get_user_var(thd, &name); + else + { + sp_variable *spv; + const Sp_rcontext_handler *rh; + LEX *lex; + /* + We call lex->find_variable() rather than thd->lex->spcont->find_variable() + to make sure package body variables are properly supported. + */ + if ((lex= thd->lex) && + (spv= lex->find_variable(&name, &rh))) + { + Item_splocal *splocal= new (thd->mem_root) + Item_splocal(thd, rh, &name, spv->offset, spv->type_handler(), 0); +#ifdef DBUG_ASSERT_EXISTS + 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= (uint)(xpath->query.end - dollar_pos); + if (len <= 32) + my_printf_error(ER_UNKNOWN_ERROR, "Unknown XPATH variable at: '%.*s'", + MYF(0), len, dollar_pos); + else + my_printf_error(ER_UNKNOWN_ERROR, "Unknown XPATH variable at: '%.32T'", + MYF(0), 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= (uint)(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 (xpath->thd->mem_root) + Item_nodeset_func_rootelement(xpath->thd, + xpath->pxml); + + return (my_xpath_parse_Expr(xpath) && + my_xpath_parse_term(xpath, MY_XPATH_LEX_EOF)); +} + + +bool Item_xml_str_func::fix_length_and_dec() +{ + max_length= MAX_BLOB_WIDTH; + return agg_arg_charsets_for_comparison(collation, args, arg_count); +} + + +bool Item_xml_str_func::fix_fields(THD *thd, Item **ref) +{ + String *xp; + MY_XPATH xpath; + int rc; + + if (Item_str_func::fix_fields(thd, ref)) + return true; + + status_var_increment(current_thd->status_var.feature_xml); + + nodeset_func= 0; + + + 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 true; + } + + if (!args[1]->const_item()) + { + my_printf_error(ER_UNKNOWN_ERROR, + "Only constant XPATH queries are supported", MYF(0)); + return true; + } + + /* + Get the XPath query text from args[1] and cache it in m_xpath_query. + Its fragments will be referenced by items created during my_xpath_parse(), + e.g. by Item_nodeset_func_axisbyname::node_name. + */ + if (!(xp= args[1]->val_str(&m_xpath_query)) || + (xp != &m_xpath_query && m_xpath_query.copy(*xp))) + return false; // Will return NULL + my_xpath_init(&xpath); + xpath.thd= thd; + xpath.cs= collation.collation; + xpath.debug= 0; + xpath.pxml= xml.parsed(); + xml.set_charset(collation.collation); + + rc= my_xpath_parse(&xpath, xp->ptr(), xp->ptr() + xp->length()); + + if (!rc) + { + uint clen= (uint)(xpath.query.end - xpath.lasttok.beg); + if (clen <= 32) + my_printf_error(ER_UNKNOWN_ERROR, "XPATH syntax error: '%.*s'", + MYF(0), clen, xpath.lasttok.beg); + else + my_printf_error(ER_UNKNOWN_ERROR, "XPATH syntax error: '%.32T'", + MYF(0), xpath.lasttok.beg); + + return true; + } + + /* + Parsing XML is a heavy operation, so if the first argument is constant, + then parse XML only one time and cache the parsed representation + together with raw text representation. + + Note, we cannot cache the entire function result even if + the first and the second arguments are constants, because + the XPath expression may have user and SP variable references, + so the function result can vary between executions. + */ + if ((args[0]->const_item() && get_xml(&xml, true)) || + !(nodeset_func= xpath.item)) + return false; // Will return NULL + + return nodeset_func->fix_fields(thd, &nodeset_func); +} + + +#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 attribute. + 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 - 1) + 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 attribute 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 attribute. + 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 + false on success + true on error +*/ +bool Item_xml_str_func::XML::parse() +{ + MY_XML_PARSER p; + MY_XML_USER_DATA user_data; + int rc; + + m_parsed_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= &m_parsed_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, m_raw_ptr->ptr(), 0); + + /* Execute XML parser */ + if ((rc= my_xml_parse(&p, m_raw_ptr->ptr(), m_raw_ptr->length())) != MY_XML_OK) + { + THD *thd= current_thd; + 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(thd, Sql_condition::WARN_LEVEL_WARN, + ER_WRONG_VALUE, + ER_THD(thd, ER_WRONG_VALUE), "XML", buf); + m_raw_ptr= (String *) 0; + } + my_xml_parser_free(&p); + + return rc != MY_XML_OK; +} + + +/* + Parse the raw XML from the given source, + optionally cache the raw XML, + remember the pointer to the raw XML. +*/ +bool Item_xml_str_func::XML::parse(String *raw_xml, bool cache) +{ + m_raw_ptr= raw_xml; + if (cache) + { + m_cached= true; + if (m_raw_ptr != &m_raw_buf && m_raw_buf.copy(*m_raw_ptr)) + { + m_raw_ptr= (String *) 0; + return true; + } + m_raw_ptr= &m_raw_buf; + } + return parse(); +} + + +const MY_XML_NODE *Item_xml_str_func::XML::node(uint idx) +{ + const MY_XML_NODE *nodebeg= (MY_XML_NODE*) m_parsed_buf.ptr(); + DBUG_ASSERT(idx < m_parsed_buf.length() / sizeof (MY_XML_NODE)); + return nodebeg + idx; +} + + +String *Item_func_xml_extractvalue::val_str(String *str) +{ + String *res; + null_value= 0; + if (!nodeset_func || get_xml(&xml) || + !(res= nodeset_func->val_str(str))) + { + null_value= 1; + return 0; + } + return res; +} + + +bool Item_func_xml_update::collect_result(String *str, + const MY_XML_NODE *cut, + const String *replace) +{ + uint offs= cut->type == MY_XML_NODE_TAG ? 1 : 0; + const char *end= cut->tagend + offs; + str->length(0); + str->set_charset(collation.collation); + return + /* Put the XML part preceding the replaced piece */ + str->append(xml.raw()->ptr(), cut->beg - xml.raw()->ptr() - offs) || + /* Put the replacement */ + str->append(replace->ptr(), replace->length()) || + /* Put the XML part following the replaced piece */ + str->append(end, xml.raw()->ptr() + xml.raw()->length() - end); +} + + +String *Item_func_xml_update::val_str(String *str) +{ + String *rep; + + null_value= 0; + if (!nodeset_func || get_xml(&xml) || + !(rep= args[2]->val_str(&tmp_value3)) || + nodeset_func->type_handler() != &type_handler_xpath_nodeset || + nodeset_func->val_native(current_thd, &tmp_native_value2)) + { + null_value= 1; + return 0; + } + + MY_XPATH_FLT *fltbeg= (MY_XPATH_FLT*) tmp_native_value2.ptr(); + MY_XPATH_FLT *fltend= (MY_XPATH_FLT*) tmp_native_value2.end(); + + /* Allow replacing of one tag only */ + if (fltend - fltbeg != 1) + { + /* TODO: perhaps add a warning that more than one tag selected */ + return xml.raw(); + } + + const MY_XML_NODE *nodebeg= xml.node(fltbeg->num); + + if (!nodebeg->level) + { + /* + Root element, without NameTest: + UpdateXML(xml, '/', 'replacement'); + Just return the replacement string. + */ + return rep; + } + + return collect_result(str, nodebeg, rep) ? (String *) NULL : str; +} |