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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.
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#include "config.h"
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static char rcsid[] not_used =
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{"$Id: ConstraintEvaluator.cc 24370 2011-03-28 16:21:32Z jimg $"
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#include "ServerFunctionsList.h"
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#include "ConstraintEvaluator.h"
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#include "ce_functions.h"
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#include "ce_parser.h"
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//#include "ce_expr.tab.hh"
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struct yy_buffer_state;
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yy_buffer_state *ce_expr_scan_string(const char *str);
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int ce_exprparse(void *arg);
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int ce_exprparse(libdap::ce_parser_arg *arg);
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// Glue routines declared in expr.lex
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void ce_expr_switch_to_buffer(void *new_buffer);
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void ce_expr_delete_buffer(void * buffer);
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void *ce_expr_string(const char *yy_str);
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extern int ce_exprdebug;
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ConstraintEvaluator::ConstraintEvaluator()
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register_functions(*this);
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// Functions are now held in BES modules. jhrg 1/30/13
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// modules load functions to this list; this class searches the list
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// instead of having it's own copy. This is very similar to the BES'
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// various List classes, but this one is part of libdap and not the
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// BES. The List class is a singleton, so each function module can
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// register it's functions to the list object.
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d_functions_list = ServerFunctionsList::TheList();
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ConstraintEvaluator::~ConstraintEvaluator()
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// delete all the constants created by the parser for CE evaluation
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for (Constants_iter j = constants.begin(); j != constants.end(); j++) {
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for (Clause_iter k = expr.begin(); k != expr.end(); k++) {
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/** Returns the first clause in a parsed constraint expression. */
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ConstraintEvaluator::Clause_iter
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ConstraintEvaluator::clause_begin()
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ConstraintEvaluator::Clause_iter ConstraintEvaluator::clause_begin()
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/** Returns a reference to the end of the list of clauses in a parsed
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constraint expression. It does not reference the last clause */
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ConstraintEvaluator::Clause_iter
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ConstraintEvaluator::clause_end()
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constraint expression. It does not reference the last clause */
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ConstraintEvaluator::Clause_iter ConstraintEvaluator::clause_end()
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/** Returns the value of the indicated clause of a constraint
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ConstraintEvaluator::clause_value(Clause_iter &iter, DDS &dds/*, const string &***/)
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bool ConstraintEvaluator::clause_value(Clause_iter &iter, DDS &dds/*, const string &***/)
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throw InternalErr(__FILE__, __LINE__,
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"There are no CE clauses for *this* DDS object.");
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throw InternalErr(__FILE__, __LINE__, "There are no CE clauses for *this* DDS object.");
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return (*iter)->value(dds);
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/** @brief Add a clause to a constraint expression.
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This function adds an operator clause to the constraint
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This function adds an operator clause to the constraint
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@param op An integer indicating the operator in use. These
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values are generated by \c bison.
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@param arg1 A pointer to the argument on the left side of the
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@param arg2 A pointer to a list of the arguments on the right
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side of the operator.
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ConstraintEvaluator::append_clause(int op, rvalue *arg1, rvalue_list *arg2)
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@param op An integer indicating the operator in use. These
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values are generated by \c bison.
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@param arg1 A pointer to the argument on the left side of the
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@param arg2 A pointer to a list of the arguments on the right
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side of the operator.
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void ConstraintEvaluator::append_clause(int op, rvalue *arg1, rvalue_list *arg2)
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Clause *clause = new Clause(op, arg1, arg2);
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/** The Constraint Evaluator maintains a list of BaseType pointers for all the
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constants that the constraint expression parser generates. These objects
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are deleted by the Constraint Evaluator destructor. Note that there are no
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list accessors; these constants are never accessed from the list. The list
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is simply a convenient way to make sure the constants are disposed of
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constants that the constraint expression parser generates. These objects
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are deleted by the Constraint Evaluator destructor. Note that there are no
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list accessors; these constants are never accessed from the list. The list
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is simply a convenient way to make sure the constants are disposed of
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ConstraintEvaluator::append_constant(BaseType *btp)
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void ConstraintEvaluator::append_constant(BaseType *btp)
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constants.push_back(btp);
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// This code was removed when I switched from CE having it's own internal
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// list of functions to using an external list.
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const string d_name;
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func_name_is(const string &name): d_name(name)
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func_name_is(const string &name) :
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bool operator()(const ConstraintEvaluator::function f)
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return f.name == d_name;
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/** The Constraint Evaluator carries with it a list of external functions it
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can use while evaluate a constraint expression. If a constraint contains
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any of these functions, the entries in the list allow the parser to evaluate
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it. The functions are of three types: those that return boolean values,
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those that return real (also called BaseType) values, and those that
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are applied during evaluation of the projection for side effect
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@note The add_function() methods will replace a function of the same name,
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so it is possible to overwrite functions in specific handlers if the
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handler need special behavior to implement one of the standard functions.
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@see ce_functions for the standard functions
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These methods are used to manipulate this list of known
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@name External Function Accessors
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can use while evaluate a constraint expression. If a constraint contains
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any of these functions, the entries in the list allow the parser to evaluate
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it. The functions are of three types: those that return boolean values,
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those that return real (also called BaseType) values, and those that
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are applied during evaluation of the projection for side effect
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@note The add_function() methods will replace a function of the same name,
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so it is possible to overwrite functions in specific handlers if the
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handler need special behavior to implement one of the standard functions.
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@see ce_functions for the standard functions
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These methods are used to manipulate this list of known
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@name External Function Accessors
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/** @brief Add a boolean function to the list. */
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ConstraintEvaluator::add_function(const string &name, bool_func f)
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void ConstraintEvaluator::add_function(const string &name, bool_func f)
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functions.remove_if(func_name_is(name));
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function func(name, f);
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/** @brief Does the current constraint expression return a BaseType
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This method does not evaluate the clause, it provides information to the
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evaluator regarding _how_ to evaluate the clause.
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@return True if the clause is a function that returns a BaseType* and
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ConstraintEvaluator::functional_expression()
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This method does not evaluate the clause, it provides information to the
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evaluator regarding _how_ to evaluate the clause.
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@return True if the clause is a function that returns a BaseType* and
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bool ConstraintEvaluator::functional_expression()
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if (expr.empty())
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Clause *cp = expr[0] ;
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Clause *cp = expr[0];
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return cp->value_clause();
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/** @brief Evaluate a function-valued constraint expression. */
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/** @brief Evaluate a function-valued constraint expression.
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ConstraintEvaluator::eval_function(DDS &dds, const string &)
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if (expr.size() != 1)
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throw InternalErr(__FILE__, __LINE__,
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"The length of the list of CE clauses is not 1.");
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throw InternalErr(__FILE__, __LINE__, "The length of the list of CE clauses is not 1.");
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Clause *cp = expr[0] ;
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Clause *cp = expr[0];
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BaseType *result;
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if (cp->value(dds, &result))
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/** @brief Does the current constraint expression return a DDS pointer?
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This method does not evaluate the clauses, it provides information to the
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evaluator regarding _how_ to evaluate the clause.
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@note Added for libdap 3.11
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@return True if the clause is a function that returns a DDS* and
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/** @brief Does the current constraint expression contain function clauses
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This method does not evaluate the clauses, it provides information to the
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evaluator regarding _how_ to evaluate the clause.
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@note Added for libdap 3.11
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@return True if the current constraint contains function clauses,
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otherwise returns False */
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bool ConstraintEvaluator::function_clauses()
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if (expr.empty())
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for (unsigned int i = 0; i < expr.size(); ++i) {
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Clause *cp = expr[i];
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if (!cp->value_clause())
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Clause *cp = expr[i];
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if (!cp->value_clause())
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/** @brief Evaluate a function-valued constraint expression that contains
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several function calls.
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This method can be called for any function-valued constraint expression.
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Unlike eval_function(), it will package the return value in a new DDS
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object. The server should free this object once it has been serialized
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@note While there is another type of function that can appear in a CE (a
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'projection function') those are evaluated by the ce parser - they are used
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to insert new variables into the DDS as a side effect of CE evaluation.
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That kind of function can never appear here; these are all functions that
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return BaseType pointers.
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@note Added for libdap 3.11 */
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several function calls.
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This method can be called for any function-valued constraint expression.
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Unlike eval_function(), it will package the return value in a new DDS
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object. The server should free this object once it has been serialized
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@note While there is another type of function that can appear in a CE (a
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'projection function') those are evaluated by the ce parser - they are used
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to insert new variables into the DDS as a side effect of CE evaluation.
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That kind of function can never appear here; these are all functions that
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return BaseType pointers.
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@note Added for libdap 3.11 */
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ConstraintEvaluator::eval_function_clauses(DDS &dds)
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if (expr.empty())
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throw InternalErr(__FILE__, __LINE__, "The constraint expression is empty.");
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throw InternalErr(__FILE__, __LINE__, "The constraint expression is empty.");
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DDS *fdds = new DDS(dds.get_factory(), "function_result_" + dds.get_dataset_name());
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for (unsigned int i = 0; i < expr.size(); ++i) {
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Clause *cp = expr[i];
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if (cp->value(dds, &result)) {
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result->set_send_p(true);
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fdds->add_var(result);
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throw Error("A function was called but failed to return a value.");
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Clause *cp = expr[i];
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if (cp->value(dds, &result)) {
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// This is correct: The function must allocate the memory for the result
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// variable. 11/30/12 jhrg
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fdds->add_var_nocopy(result);
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throw Error("A function was called but failed to return a value.");
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/** @brief Evaluate a function-valued constraint expression that contains
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several function calls. Takes and returns a DataDDS.
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@see ConstraintEvaluator::eval_function_clauses(DataDDS &dds)
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@note Added for libdap 3.11 */
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several function calls. Takes and returns a DataDDS.
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@todo Change this so that the new variables are inserted into the
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original DDS object - this will allow constraints that mix simple
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projections with function calls. The function is responsible for
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setting the new variable's read_p property and this 'evaluator'
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sets the send_p property. The original variables would have to be
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removed from the original DDS for this to work or the names of
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the new variables would have to not clash with the original variables'
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@see ConstraintEvaluator::eval_function_clauses(DataDDS &dds)
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@note Added for libdap 3.11 */
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ConstraintEvaluator::eval_function_clauses(DataDDS &dds)
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if (expr.empty())
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throw InternalErr(__FILE__, __LINE__, "The constraint expression is empty.");
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throw InternalErr(__FILE__, __LINE__, "The constraint expression is empty.");
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DataDDS *fdds = new DataDDS(dds.get_factory(),
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"function_result_" + dds.get_dataset_name(),
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dds.get_version(), dds.get_protocol());
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DataDDS *fdds = new DataDDS(dds.get_factory(), "function_result_" + dds.get_dataset_name(), dds.get_version(),
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for (unsigned int i = 0; i < expr.size(); ++i) {
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Clause *cp = expr[i];
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if (cp->value(dds, &result)) {
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result->set_send_p(true);
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fdds->add_var(result);
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throw Error("A function was called but failed to return a value.");
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Clause *cp = expr[i];
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if (cp->value(dds, &result)) {
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fdds->add_var_nocopy(result);
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throw Error("A function was called but failed to return a value.");
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/** @brief Does the current constraint expression return a boolean value? */
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ConstraintEvaluator::boolean_expression()
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bool ConstraintEvaluator::boolean_expression()
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if (expr.empty())
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/** @brief Evaluate a boolean-valued constraint expression.
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This is main method for the evaluator ans is called by the
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BaseType::serialize() methods.
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This is main method for the evaluator ans is called by the
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BaseType::serialize() methods.
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@param dds Use these variables when evaluating the expressions.
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@param dataset This string is passed to the read() methods.
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@return True if the expression is true, false otherwise. */
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ConstraintEvaluator::eval_selection(DDS &dds, const string &)
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@param dds Use these variables when evaluating the expressions.
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@param dataset This string is passed to the read() methods.
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@return True if the expression is true, false otherwise. */
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bool ConstraintEvaluator::eval_selection(DDS &dds, const string &)
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if (expr.empty()) {
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DBG(cerr << "No selection recorded" << endl);
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/** @brief Parse the constraint expression given the current DDS.
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Evaluate the constraint expression; return the value of the expression.
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As a side effect, mark the DDS so that BaseType's mfuncs can be used to
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correctly read the variable's value and send it to the client.
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Evaluate the constraint expression; return the value of the expression.
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As a side effect, mark the DDS so that BaseType's mfuncs can be used to
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correctly read the variable's value and send it to the client.
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@param constraint A string containing the constraint expression.
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@param dds The DDS that provides the environment within which the
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constraint is evaluated.
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@exception Throws Error if the constraint does not parse. */
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ConstraintEvaluator::parse_constraint(const string &constraint, DDS &dds)
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@param constraint A string containing the constraint expression.
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@param dds The DDS that provides the environment within which the
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constraint is evaluated.
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@exception Throws Error if the constraint does not parse. */
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void ConstraintEvaluator::parse_constraint(const string &constraint, DDS &dds)
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void *buffer = ce_expr_string(constraint.c_str());
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// Toggle this to debug the parser. A last resort...
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ce_exprdebug = false;
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ce_expr_switch_to_buffer(buffer);
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ce_parser_arg arg(this, &dds);
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// For all errors, exprparse will throw Error.
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ce_exprparse((void *)&arg);
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ce_expr_delete_buffer(buffer);
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ce_expr_delete_buffer(buffer);
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// Make sure to remove the buffer when there's an error
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ce_expr_delete_buffer(buffer);
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} // namespace libdap
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removed
ConstraintEvaluator.cc
