libdap  Updated for version 3.20.1
libdap4 is an implementation of OPeNDAP's DAP protocol.
D4ConstraintEvaluator.cc
1 // -*- mode: c++; c-basic-offset:4 -*-
2 
3 // This file is part of libdap, A C++ implementation of the OPeNDAP Data
4 // Access Protocol.
5 
6 // Copyright (c) 2002,2003 OPeNDAP, Inc.
7 // Author: James Gallagher <jgallagher@opendap.org>
8 //
9 // This library is free software; you can redistribute it and/or
10 // modify it under the terms of the GNU Lesser General Public
11 // License as published by the Free Software Foundation; either
12 // version 2.1 of the License, or (at your option) any later version.
13 //
14 // This library is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 // Lesser General Public License for more details.
18 //
19 // You should have received a copy of the GNU Lesser General Public
20 // License along with this library; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 //
23 // You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.
24 
25 #include <string>
26 #include <sstream>
27 #include <iterator>
28 
29 //#define DODS_DEBUG
30 
31 #include "D4CEScanner.h"
32 #include "D4ConstraintEvaluator.h"
33 #include "d4_ce_parser.tab.hh"
34 
35 #include "DMR.h"
36 #include "D4Group.h"
37 #include "D4Dimensions.h"
38 #include "D4Maps.h"
39 #include "BaseType.h"
40 #include "Array.h"
41 #include "Constructor.h"
42 #include "D4Sequence.h"
43 
44 #include "D4RValue.h"
45 #include "D4FilterClause.h"
46 
47 #include "escaping.h"
48 #include "parser.h" // for get_ull()
49 #include "debug.h"
50 
51 namespace libdap {
52 
53 bool D4ConstraintEvaluator::parse(const std::string &expr)
54 {
55  d_expr = expr; // set for error messages. See the %initial-action section of .yy
56 
57  std::istringstream iss(expr);
58  D4CEScanner scanner(iss);
59  D4CEParser parser(scanner, *this /* driver */);
60 
61  if (trace_parsing()) {
62  parser.set_debug_level(1);
63  parser.set_debug_stream(std::cerr);
64  }
65 
66  return parser.parse() == 0;
67 }
68 
69 void D4ConstraintEvaluator::throw_not_found(const string &id, const string &ident)
70 {
71  throw Error(no_such_variable, d_expr + ": The variable " + id + " was not found in the dataset (" + ident + ").");
72 }
73 
74 void D4ConstraintEvaluator::throw_not_array(const string &id, const string &ident)
75 {
76  throw Error(no_such_variable, d_expr + ": The variable '" + id + "' is not an Array variable (" + ident + ").");
77 }
78 
79 void D4ConstraintEvaluator::search_for_and_mark_arrays(BaseType *btp)
80 {
81  DBG(cerr << "Entering D4ConstraintEvaluator::search_for_and_mark_arrays...(" << btp->name() << ")" << endl);
82 
83  assert(btp->is_constructor_type());
84 
85  Constructor *ctor = static_cast<Constructor*>(btp);
86  for (Constructor::Vars_iter i = ctor->var_begin(), e = ctor->var_end(); i != e; ++i) {
87  switch ((*i)->type()) {
88  case dods_array_c:
89  DBG(cerr << "Found an array: " << (*i)->name() << endl);
90  mark_array_variable(*i);
91  break;
92  case dods_structure_c:
93  case dods_sequence_c:
94  DBG(cerr << "Found a ctor: " << (*i)->name() << endl);
95  search_for_and_mark_arrays(*i);
96  break;
97  default:
98  break;
99  }
100  }
101 }
102 
112 BaseType *
113 D4ConstraintEvaluator::mark_variable(BaseType *btp)
114 {
115  assert(btp);
116 
117  DBG(cerr << "In D4ConstraintEvaluator::mark_variable... (" << btp->name() << "; " << btp->type_name() << ")" << endl);
118 
119  btp->set_send_p(true);
120 
121  if (btp->type() == dods_array_c) {
122  mark_array_variable(btp);
123  }
124 
125  // Test for Constructors and marks arrays they contain
126  if (btp->is_constructor_type()) {
127  search_for_and_mark_arrays(btp);
128  }
129  else if (btp->type() == dods_array_c && btp->var() && btp->var()->is_constructor_type()) {
130  search_for_and_mark_arrays(btp->var());
131  }
132 
133  // Now set the parent variables
134  BaseType *parent = btp->get_parent();
135  while (parent) {
136  parent->BaseType::set_send_p(true); // Just set the parent using BaseType's impl.
137  parent = parent->get_parent();
138  }
139 
140  return btp;
141 }
142 
143 static bool array_uses_shared_dimension(Array *map, D4Dimension *source_dim)
144 {
145  for (Array::Dim_iter d = map->dim_begin(), e = map->dim_end(); d != e; ++d) {
146  if (source_dim->name() == (*d).name) return true;
147  }
148 
149  return false;
150 }
151 
165 // Note: If a Map is not part of the current projection, do not include mention of it
166 // in the response DMR (CDMR)
167 BaseType *
168 D4ConstraintEvaluator::mark_array_variable(BaseType *btp)
169 {
170  assert(btp->type() == dods_array_c);
171 
172  Array *a = static_cast<Array*>(btp);
173 
174  // If an array appears in a CE without the slicing operators ([]) we still have to
175  // call add_constraint(...) for all of it's sdims for them to appear in
176  // the Constrained DMR.
177  if (d_indexes.empty()) {
178  for (Array::Dim_iter d = a->dim_begin(), de = a->dim_end(); d != de; ++d) {
179  D4Dimension *dim = a->dimension_D4dim(d);
180  if (dim) {
181  a->add_constraint(d, dim);
182  }
183  }
184  }
185  else {
186  // Test that the indexes and dimensions match in number
187  if (d_indexes.size() != a->dimensions())
188  throw Error(malformed_expr, "The index constraint for '" + btp->name() + "' does not match its rank.");
189 
190  Array::Dim_iter d = a->dim_begin();
191  for (vector<index>::iterator i = d_indexes.begin(), e = d_indexes.end(); i != e; ++i) {
192  if ((*i).stride > (unsigned long long) (a->dimension_stop(d, false) - a->dimension_start(d, false)) + 1)
193  throw Error(malformed_expr,
194  "For '" + btp->name()
195  + "', the index stride value is greater than the number of elements in the Array");
196  if (!(*i).rest
197  && ((*i).stop) > (unsigned long long) (a->dimension_stop(d, false) - a->dimension_start(d, false)) + 1)
198  throw Error(malformed_expr,
199  "For '" + btp->name()
200  + "', the index stop value is greater than the number of elements in the Array");
201 
202  D4Dimension *dim = a->dimension_D4dim(d);
203 
204  // In a DAP4 CE, specifying '[]' as an array dimension slice has two meanings.
205  // It can mean 'all the elements' of the dimension or 'apply the slicing inherited
206  // from the shared dimension'. The latter might be provide 'all the elements'
207  // but regardless, the Array object must record the CE correctly.
208 
209  if (dim && (*i).empty) {
210  // This case corresponds to a CE that uses the '[]' notation for a
211  // particular dimension - meaning, use the Shared Dimension size for
212  // this dimension's 'slice'.
213  a->add_constraint(d, dim); // calls set_used_by_projected_var(true) + more
214  }
215  else {
216  // This case corresponds to a 'local dimension slice' (See sections 8.6.2 and
217  // 8.7 of the spec as of 4/12/16). When a local dimension slice is used, drop
218  // the Map(s) that include that dimension. This enables people to constrain
219  // an Array when some of the Array's dimensions don't use Shared Dimensions
220  // but others do.
221 
222  // First apply the constraint to the Array's dimension
223  a->add_constraint(d, (*i).start, (*i).stride, (*i).rest ? -1 : (*i).stop);
224 
225  // Then, if the Array has Maps, scan those Maps for any that use dimensions
226  // that match the name of this particular dimension. If any such Maps are found
227  // remove them. This ensure that the Array can be constrained using the 'local
228  // dimension slice' without the constrained DMR containing references to Maps
229  // that don't exist (or are otherwise nonsensical).
230  //
231  // This code came about as a fix for problems discovered during testing of
232  // local dimension slices. See https://opendap.atlassian.net/browse/HYRAX-98
233  // jhrg 4/12/16
234  if (!a->maps()->empty()) {
235  for (D4Maps::D4MapsIter m = a->maps()->map_begin(), e = a->maps()->map_end(); m != e; ++m) {
236  if ((*m)->array() == 0)
237  throw Error(malformed_expr,
238  "An array with Maps was found, but one of the Maps was not defined correctly.");
239 
240  Array *map = const_cast<Array*>((*m)->array()); // Array lacks const iterator support
241  // Added a test to ensure 'dim' is not null. This could be the case if
242  // execution gets here and the index *i was not empty. jhrg 4/18/17
243  if (dim && array_uses_shared_dimension(map, dim)) {
244  D4Map *map_to_be_removed = *m;
245  a->maps()->remove_map(map_to_be_removed); // Invalidates the iterator
246  delete map_to_be_removed; // removed from container; delete
247  break; // must leave the for loop because 'm' is now invalid
248  }
249  }
250  }
251  }
252 
253  ++d;
254  }
255  }
256 
257  d_indexes.clear(); // Clear the info so the next slice expression can be parsed.
258 
259  return btp;
260 }
261 
270 D4Dimension *
271 D4ConstraintEvaluator::slice_dimension(const std::string &id, const index &i)
272 {
273  D4Dimension *dim = dmr()->root()->find_dim(id);
274 
275  if (i.stride > dim->size())
276  throw Error(malformed_expr,
277  "For '" + id + "', the index stride value is greater than the size of the dimension");
278  if (!i.rest && (i.stop > dim->size() - 1))
279  throw Error(malformed_expr, "For '" + id + "', the index stop value is greater than the size of the dimension");
280 
281  dim->set_constraint(i.start, i.stride, i.rest ? dim->size() - 1 : i.stop);
282 
283  return dim;
284 }
285 
286 D4ConstraintEvaluator::index D4ConstraintEvaluator::make_index(const std::string &i)
287 {
288  unsigned long long v = get_int64(i.c_str());
289  return index(v, 1, v, false, false /*empty*/, "");
290 }
291 
292 D4ConstraintEvaluator::index D4ConstraintEvaluator::make_index(const std::string &i, const std::string &s,
293  const std::string &e)
294 {
295  return index(get_int64(i.c_str()), get_int64(s.c_str()), get_int64(e.c_str()), false, false /*empty*/, "");
296 }
297 
298 D4ConstraintEvaluator::index D4ConstraintEvaluator::make_index(const std::string &i, unsigned long long s,
299  const std::string &e)
300 {
301  return index(get_int64(i.c_str()), s, get_int64(e.c_str()), false, false /*empty*/, "");
302 }
303 
304 D4ConstraintEvaluator::index D4ConstraintEvaluator::make_index(const std::string &i, const std::string &s)
305 {
306  return index(get_int64(i.c_str()), get_int64(s.c_str()), 0, true, false /*empty*/, "");
307 }
308 
309 D4ConstraintEvaluator::index D4ConstraintEvaluator::make_index(const std::string &i, unsigned long long s)
310 {
311  return index(get_uint64(i.c_str()), s, 0, true, false /*empty*/, "");
312 }
313 
314 static string expr_msg(const std::string &op, const std::string &arg1, const std::string &arg2)
315 {
316  return "(" + arg1 + " " + op + " " + arg2 + ").";
317 }
318 
336 static D4FilterClause::ops get_op_code(const std::string &op)
337 {
338  DBGN(cerr << "Entering " << __PRETTY_FUNCTION__ << endl << "op: " << op << endl);
339 
340  if (op == "<")
341  return D4FilterClause::less;
342  else if (op == ">")
343  return D4FilterClause::greater;
344  else if (op == "<=")
345  return D4FilterClause::less_equal;
346  else if (op == ">=")
347  return D4FilterClause::greater_equal;
348  else if (op == "==")
349  return D4FilterClause::equal;
350  else if (op == "!=")
351  return D4FilterClause::not_equal;
352  else if (op == "~=")
353  return D4FilterClause::match;
354  else
355  throw Error(malformed_expr, "The opertator '" + op + "' is not supported.");
356 }
357 
379 void D4ConstraintEvaluator::add_filter_clause(const std::string &op, const std::string &arg1, const std::string &arg2)
380 {
381  DBG(cerr << "Entering: " << __PRETTY_FUNCTION__ << endl);
382 
383  // Check that there really is a D4Sequence associated with this filter clause.
384  D4Sequence *s = dynamic_cast<D4Sequence*>(top_basetype());
385  if (!s)
386  throw Error(malformed_expr,
387  "When a filter expression is used, it must be bound to a Sequence variable: " + expr_msg(op, arg1, arg2));
388 
389  DBG(cerr << "s->name(): " << s->name() << endl);
390 
391  // Check that arg1 and 2 are valid
392  BaseType *a1 = s->var(arg1);
393  BaseType *a2 = s->var(arg2);
394  DBG(cerr << "a1: " << a1 << ", a2: " << a2 << endl);
395 
396  if (a1 && a2)
397  throw Error(malformed_expr,
398  "One of the arguments in a filter expression must be a constant: " + expr_msg(op, arg1, arg2));
399  if (!(a1 || a2))
400  throw Error(malformed_expr,
401  "One of the arguments in a filter expression must be a variable in a Sequence: "
402  + expr_msg(op, arg1, arg2));
403 
404  // Now we know a1 XOR a2 is true
405  if (a1) {
406  s->clauses().add_clause(new D4FilterClause(get_op_code(op), new D4RValue(a1), D4RValueFactory(arg2)));
407  }
408  else {
409  s->clauses().add_clause(new D4FilterClause(get_op_code(op), D4RValueFactory(arg1), new D4RValue(a2)));
410  }
411 }
412 
419 string &
420 D4ConstraintEvaluator::remove_quotes(string &s)
421 {
422  if (*s.begin() == '\"' && *(s.end() - 1) == '\"') {
423  s.erase(s.begin());
424  s.erase(s.end() - 1);
425  }
426 
427  return s;
428 }
429 
430 // This method is called from the parser (see d4_ce_parser.yy, down in the code
431 // section). This will be called during the call to D4CEParser::parse(), that
432 // is inside D4ConstraintEvaluator::parse(...)
433 void D4ConstraintEvaluator::error(const libdap::location &l, const std::string &m)
434 {
435  ostringstream oss;
436  oss << l << ": " << m << ends;
437  throw Error(malformed_expr, oss.str());
438 }
439 
440 } /* namespace libdap */
D4Dimension * find_dim(const string &path)
Find the dimension using a path. Using the DAP4 name syntax, lookup a dimension. The dimension must b...
Definition: D4Group.cc:275
D4Group * root()
Definition: DMR.cc:360
top level DAP object to house generic methods
Definition: AlarmHandler.h:35
std::vector< dimension >::iterator Dim_iter
Definition: Array.h:206
D4RValue * D4RValueFactory(std::string cpps)
Build an appropriate RValue.
Definition: D4RValue.cc:218