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29//
30// Author: wan@google.com (Zhanyong Wan)
31
32// Google Mock - a framework for writing C++ mock classes.
33//
34// This file implements Matcher<const string&>, Matcher<string>, and
35// utilities for defining matchers.
36
37#include "gmock/gmock-matchers.h"
38#include "gmock/gmock-generated-matchers.h"
39
40#include <string.h>
41#include <sstream>
42#include <string>
43
44namespace testing {
45
46// Constructs a matcher that matches a const string& whose value is
47// equal to s.
48Matcher<const internal::string&>::Matcher(const internal::string& s) {
49  *this = Eq(s);
50}
51
52// Constructs a matcher that matches a const string& whose value is
53// equal to s.
54Matcher<const internal::string&>::Matcher(const char* s) {
55  *this = Eq(internal::string(s));
56}
57
58// Constructs a matcher that matches a string whose value is equal to s.
59Matcher<internal::string>::Matcher(const internal::string& s) { *this = Eq(s); }
60
61// Constructs a matcher that matches a string whose value is equal to s.
62Matcher<internal::string>::Matcher(const char* s) {
63  *this = Eq(internal::string(s));
64}
65
66#if GTEST_HAS_STRING_PIECE_
67// Constructs a matcher that matches a const StringPiece& whose value is
68// equal to s.
69Matcher<const StringPiece&>::Matcher(const internal::string& s) {
70  *this = Eq(s);
71}
72
73// Constructs a matcher that matches a const StringPiece& whose value is
74// equal to s.
75Matcher<const StringPiece&>::Matcher(const char* s) {
76  *this = Eq(internal::string(s));
77}
78
79// Constructs a matcher that matches a const StringPiece& whose value is
80// equal to s.
81Matcher<const StringPiece&>::Matcher(StringPiece s) {
82  *this = Eq(s.ToString());
83}
84
85// Constructs a matcher that matches a StringPiece whose value is equal to s.
86Matcher<StringPiece>::Matcher(const internal::string& s) {
87  *this = Eq(s);
88}
89
90// Constructs a matcher that matches a StringPiece whose value is equal to s.
91Matcher<StringPiece>::Matcher(const char* s) {
92  *this = Eq(internal::string(s));
93}
94
95// Constructs a matcher that matches a StringPiece whose value is equal to s.
96Matcher<StringPiece>::Matcher(StringPiece s) {
97  *this = Eq(s.ToString());
98}
99#endif  // GTEST_HAS_STRING_PIECE_
100
101namespace internal {
102
103// Joins a vector of strings as if they are fields of a tuple; returns
104// the joined string.
105GTEST_API_ string JoinAsTuple(const Strings& fields) {
106  switch (fields.size()) {
107    case 0:
108      return "";
109    case 1:
110      return fields[0];
111    default:
112      string result = "(" + fields[0];
113      for (size_t i = 1; i < fields.size(); i++) {
114        result += ", ";
115        result += fields[i];
116      }
117      result += ")";
118      return result;
119  }
120}
121
122// Returns the description for a matcher defined using the MATCHER*()
123// macro where the user-supplied description string is "", if
124// 'negation' is false; otherwise returns the description of the
125// negation of the matcher.  'param_values' contains a list of strings
126// that are the print-out of the matcher's parameters.
127GTEST_API_ string FormatMatcherDescription(bool negation,
128                                           const char* matcher_name,
129                                           const Strings& param_values) {
130  string result = ConvertIdentifierNameToWords(matcher_name);
131  if (param_values.size() >= 1)
132    result += " " + JoinAsTuple(param_values);
133  return negation ? "not (" + result + ")" : result;
134}
135
136// FindMaxBipartiteMatching and its helper class.
137//
138// Uses the well-known Ford-Fulkerson max flow method to find a maximum
139// bipartite matching. Flow is considered to be from left to right.
140// There is an implicit source node that is connected to all of the left
141// nodes, and an implicit sink node that is connected to all of the
142// right nodes. All edges have unit capacity.
143//
144// Neither the flow graph nor the residual flow graph are represented
145// explicitly. Instead, they are implied by the information in 'graph' and
146// a vector<int> called 'left_' whose elements are initialized to the
147// value kUnused. This represents the initial state of the algorithm,
148// where the flow graph is empty, and the residual flow graph has the
149// following edges:
150//   - An edge from source to each left_ node
151//   - An edge from each right_ node to sink
152//   - An edge from each left_ node to each right_ node, if the
153//     corresponding edge exists in 'graph'.
154//
155// When the TryAugment() method adds a flow, it sets left_[l] = r for some
156// nodes l and r. This induces the following changes:
157//   - The edges (source, l), (l, r), and (r, sink) are added to the
158//     flow graph.
159//   - The same three edges are removed from the residual flow graph.
160//   - The reverse edges (l, source), (r, l), and (sink, r) are added
161//     to the residual flow graph, which is a directional graph
162//     representing unused flow capacity.
163//
164// When the method augments a flow (moving left_[l] from some r1 to some
165// other r2), this can be thought of as "undoing" the above steps with
166// respect to r1 and "redoing" them with respect to r2.
167//
168// It bears repeating that the flow graph and residual flow graph are
169// never represented explicitly, but can be derived by looking at the
170// information in 'graph' and in left_.
171//
172// As an optimization, there is a second vector<int> called right_ which
173// does not provide any new information. Instead, it enables more
174// efficient queries about edges entering or leaving the right-side nodes
175// of the flow or residual flow graphs. The following invariants are
176// maintained:
177//
178// left[l] == kUnused or right[left[l]] == l
179// right[r] == kUnused or left[right[r]] == r
180//
181// . [ source ]                                        .
182// .   |||                                             .
183// .   |||                                             .
184// .   ||\--> left[0]=1  ---\    right[0]=-1 ----\     .
185// .   ||                   |                    |     .
186// .   |\---> left[1]=-1    \--> right[1]=0  ---\|     .
187// .   |                                        ||     .
188// .   \----> left[2]=2  ------> right[2]=2  --\||     .
189// .                                           |||     .
190// .         elements           matchers       vvv     .
191// .                                         [ sink ]  .
192//
193// See Also:
194//   [1] Cormen, et al (2001). "Section 26.2: The Ford–Fulkerson method".
195//       "Introduction to Algorithms (Second ed.)", pp. 651–664.
196//   [2] "Ford–Fulkerson algorithm", Wikipedia,
197//       'http://en.wikipedia.org/wiki/Ford%E2%80%93Fulkerson_algorithm'
198class MaxBipartiteMatchState {
199 public:
200  explicit MaxBipartiteMatchState(const MatchMatrix& graph)
201      : graph_(&graph),
202        left_(graph_->LhsSize(), kUnused),
203        right_(graph_->RhsSize(), kUnused) {
204  }
205
206  // Returns the edges of a maximal match, each in the form {left, right}.
207  ElementMatcherPairs Compute() {
208    // 'seen' is used for path finding { 0: unseen, 1: seen }.
209    ::std::vector<char> seen;
210    // Searches the residual flow graph for a path from each left node to
211    // the sink in the residual flow graph, and if one is found, add flow
212    // to the graph. It's okay to search through the left nodes once. The
213    // edge from the implicit source node to each previously-visited left
214    // node will have flow if that left node has any path to the sink
215    // whatsoever. Subsequent augmentations can only add flow to the
216    // network, and cannot take away that previous flow unit from the source.
217    // Since the source-to-left edge can only carry one flow unit (or,
218    // each element can be matched to only one matcher), there is no need
219    // to visit the left nodes more than once looking for augmented paths.
220    // The flow is known to be possible or impossible by looking at the
221    // node once.
222    for (size_t ilhs = 0; ilhs < graph_->LhsSize(); ++ilhs) {
223      // Reset the path-marking vector and try to find a path from
224      // source to sink starting at the left_[ilhs] node.
225      GTEST_CHECK_(left_[ilhs] == kUnused)
226          << "ilhs: " << ilhs << ", left_[ilhs]: " << left_[ilhs];
227      // 'seen' initialized to 'graph_->RhsSize()' copies of 0.
228      seen.assign(graph_->RhsSize(), 0);
229      TryAugment(ilhs, &seen);
230    }
231    ElementMatcherPairs result;
232    for (size_t ilhs = 0; ilhs < left_.size(); ++ilhs) {
233      size_t irhs = left_[ilhs];
234      if (irhs == kUnused) continue;
235      result.push_back(ElementMatcherPair(ilhs, irhs));
236    }
237    return result;
238  }
239
240 private:
241  static const size_t kUnused = static_cast<size_t>(-1);
242
243  // Perform a depth-first search from left node ilhs to the sink.  If a
244  // path is found, flow is added to the network by linking the left and
245  // right vector elements corresponding each segment of the path.
246  // Returns true if a path to sink was found, which means that a unit of
247  // flow was added to the network. The 'seen' vector elements correspond
248  // to right nodes and are marked to eliminate cycles from the search.
249  //
250  // Left nodes will only be explored at most once because they
251  // are accessible from at most one right node in the residual flow
252  // graph.
253  //
254  // Note that left_[ilhs] is the only element of left_ that TryAugment will
255  // potentially transition from kUnused to another value. Any other
256  // left_ element holding kUnused before TryAugment will be holding it
257  // when TryAugment returns.
258  //
259  bool TryAugment(size_t ilhs, ::std::vector<char>* seen) {
260    for (size_t irhs = 0; irhs < graph_->RhsSize(); ++irhs) {
261      if ((*seen)[irhs])
262        continue;
263      if (!graph_->HasEdge(ilhs, irhs))
264        continue;
265      // There's an available edge from ilhs to irhs.
266      (*seen)[irhs] = 1;
267      // Next a search is performed to determine whether
268      // this edge is a dead end or leads to the sink.
269      //
270      // right_[irhs] == kUnused means that there is residual flow from
271      // right node irhs to the sink, so we can use that to finish this
272      // flow path and return success.
273      //
274      // Otherwise there is residual flow to some ilhs. We push flow
275      // along that path and call ourselves recursively to see if this
276      // ultimately leads to sink.
277      if (right_[irhs] == kUnused || TryAugment(right_[irhs], seen)) {
278        // Add flow from left_[ilhs] to right_[irhs].
279        left_[ilhs] = irhs;
280        right_[irhs] = ilhs;
281        return true;
282      }
283    }
284    return false;
285  }
286
287  const MatchMatrix* graph_;  // not owned
288  // Each element of the left_ vector represents a left hand side node
289  // (i.e. an element) and each element of right_ is a right hand side
290  // node (i.e. a matcher). The values in the left_ vector indicate
291  // outflow from that node to a node on the the right_ side. The values
292  // in the right_ indicate inflow, and specify which left_ node is
293  // feeding that right_ node, if any. For example, left_[3] == 1 means
294  // there's a flow from element #3 to matcher #1. Such a flow would also
295  // be redundantly represented in the right_ vector as right_[1] == 3.
296  // Elements of left_ and right_ are either kUnused or mutually
297  // referent. Mutually referent means that left_[right_[i]] = i and
298  // right_[left_[i]] = i.
299  ::std::vector<size_t> left_;
300  ::std::vector<size_t> right_;
301
302  GTEST_DISALLOW_ASSIGN_(MaxBipartiteMatchState);
303};
304
305const size_t MaxBipartiteMatchState::kUnused;
306
307GTEST_API_ ElementMatcherPairs
308FindMaxBipartiteMatching(const MatchMatrix& g) {
309  return MaxBipartiteMatchState(g).Compute();
310}
311
312static void LogElementMatcherPairVec(const ElementMatcherPairs& pairs,
313                                     ::std::ostream* stream) {
314  typedef ElementMatcherPairs::const_iterator Iter;
315  ::std::ostream& os = *stream;
316  os << "{";
317  const char *sep = "";
318  for (Iter it = pairs.begin(); it != pairs.end(); ++it) {
319    os << sep << "\n  ("
320       << "element #" << it->first << ", "
321       << "matcher #" << it->second << ")";
322    sep = ",";
323  }
324  os << "\n}";
325}
326
327// Tries to find a pairing, and explains the result.
328GTEST_API_ bool FindPairing(const MatchMatrix& matrix,
329                            MatchResultListener* listener) {
330  ElementMatcherPairs matches = FindMaxBipartiteMatching(matrix);
331
332  size_t max_flow = matches.size();
333  bool result = (max_flow == matrix.RhsSize());
334
335  if (!result) {
336    if (listener->IsInterested()) {
337      *listener << "where no permutation of the elements can "
338                   "satisfy all matchers, and the closest match is "
339                << max_flow << " of " << matrix.RhsSize()
340                << " matchers with the pairings:\n";
341      LogElementMatcherPairVec(matches, listener->stream());
342    }
343    return false;
344  }
345
346  if (matches.size() > 1) {
347    if (listener->IsInterested()) {
348      const char *sep = "where:\n";
349      for (size_t mi = 0; mi < matches.size(); ++mi) {
350        *listener << sep << " - element #" << matches[mi].first
351                  << " is matched by matcher #" << matches[mi].second;
352        sep = ",\n";
353      }
354    }
355  }
356  return true;
357}
358
359bool MatchMatrix::NextGraph() {
360  for (size_t ilhs = 0; ilhs < LhsSize(); ++ilhs) {
361    for (size_t irhs = 0; irhs < RhsSize(); ++irhs) {
362      char& b = matched_[SpaceIndex(ilhs, irhs)];
363      if (!b) {
364        b = 1;
365        return true;
366      }
367      b = 0;
368    }
369  }
370  return false;
371}
372
373void MatchMatrix::Randomize() {
374  for (size_t ilhs = 0; ilhs < LhsSize(); ++ilhs) {
375    for (size_t irhs = 0; irhs < RhsSize(); ++irhs) {
376      char& b = matched_[SpaceIndex(ilhs, irhs)];
377      b = static_cast<char>(rand() & 1);  // NOLINT
378    }
379  }
380}
381
382string MatchMatrix::DebugString() const {
383  ::std::stringstream ss;
384  const char *sep = "";
385  for (size_t i = 0; i < LhsSize(); ++i) {
386    ss << sep;
387    for (size_t j = 0; j < RhsSize(); ++j) {
388      ss << HasEdge(i, j);
389    }
390    sep = ";";
391  }
392  return ss.str();
393}
394
395void UnorderedElementsAreMatcherImplBase::DescribeToImpl(
396    ::std::ostream* os) const {
397  if (matcher_describers_.empty()) {
398    *os << "is empty";
399    return;
400  }
401  if (matcher_describers_.size() == 1) {
402    *os << "has " << Elements(1) << " and that element ";
403    matcher_describers_[0]->DescribeTo(os);
404    return;
405  }
406  *os << "has " << Elements(matcher_describers_.size())
407      << " and there exists some permutation of elements such that:\n";
408  const char* sep = "";
409  for (size_t i = 0; i != matcher_describers_.size(); ++i) {
410    *os << sep << " - element #" << i << " ";
411    matcher_describers_[i]->DescribeTo(os);
412    sep = ", and\n";
413  }
414}
415
416void UnorderedElementsAreMatcherImplBase::DescribeNegationToImpl(
417    ::std::ostream* os) const {
418  if (matcher_describers_.empty()) {
419    *os << "isn't empty";
420    return;
421  }
422  if (matcher_describers_.size() == 1) {
423    *os << "doesn't have " << Elements(1)
424        << ", or has " << Elements(1) << " that ";
425    matcher_describers_[0]->DescribeNegationTo(os);
426    return;
427  }
428  *os << "doesn't have " << Elements(matcher_describers_.size())
429      << ", or there exists no permutation of elements such that:\n";
430  const char* sep = "";
431  for (size_t i = 0; i != matcher_describers_.size(); ++i) {
432    *os << sep << " - element #" << i << " ";
433    matcher_describers_[i]->DescribeTo(os);
434    sep = ", and\n";
435  }
436}
437
438// Checks that all matchers match at least one element, and that all
439// elements match at least one matcher. This enables faster matching
440// and better error reporting.
441// Returns false, writing an explanation to 'listener', if and only
442// if the success criteria are not met.
443bool UnorderedElementsAreMatcherImplBase::
444VerifyAllElementsAndMatchersAreMatched(
445    const ::std::vector<string>& element_printouts,
446    const MatchMatrix& matrix,
447    MatchResultListener* listener) const {
448  bool result = true;
449  ::std::vector<char> element_matched(matrix.LhsSize(), 0);
450  ::std::vector<char> matcher_matched(matrix.RhsSize(), 0);
451
452  for (size_t ilhs = 0; ilhs < matrix.LhsSize(); ilhs++) {
453    for (size_t irhs = 0; irhs < matrix.RhsSize(); irhs++) {
454      char matched = matrix.HasEdge(ilhs, irhs);
455      element_matched[ilhs] |= matched;
456      matcher_matched[irhs] |= matched;
457    }
458  }
459
460  {
461    const char* sep =
462        "where the following matchers don't match any elements:\n";
463    for (size_t mi = 0; mi < matcher_matched.size(); ++mi) {
464      if (matcher_matched[mi])
465        continue;
466      result = false;
467      if (listener->IsInterested()) {
468        *listener << sep << "matcher #" << mi << ": ";
469        matcher_describers_[mi]->DescribeTo(listener->stream());
470        sep = ",\n";
471      }
472    }
473  }
474
475  {
476    const char* sep =
477        "where the following elements don't match any matchers:\n";
478    const char* outer_sep = "";
479    if (!result) {
480      outer_sep = "\nand ";
481    }
482    for (size_t ei = 0; ei < element_matched.size(); ++ei) {
483      if (element_matched[ei])
484        continue;
485      result = false;
486      if (listener->IsInterested()) {
487        *listener << outer_sep << sep << "element #" << ei << ": "
488                  << element_printouts[ei];
489        sep = ",\n";
490        outer_sep = "";
491      }
492    }
493  }
494  return result;
495}
496
497}  // namespace internal
498}  // namespace testing
499