Googletest export
Fix Theta(N^2) memory usage of EXPECT_EQ(string) when the strings don't match.
The underlying CalculateOptimalEdits() implementation used a simple
dynamic-programming approach that always used N^2 memory and time. This meant
that tests for equality of large strings were ticking time bombs: They'd work
fine as long as the test passed, but as soon as the strings differed the test
would OOM, which is very hard to debug.
I switched it out for a Dijkstra search, which is still worst-case O(N^2), but
in the usual case of mostly-matching strings, it is much closer to linear.
PiperOrigin-RevId: 210405025
diff --git a/googletest/include/gtest/internal/gtest-internal.h b/googletest/include/gtest/internal/gtest-internal.h
index 9593a45..1c2824d 100644
--- a/googletest/include/gtest/internal/gtest-internal.h
+++ b/googletest/include/gtest/internal/gtest-internal.h
@@ -159,15 +159,15 @@
#endif // GTEST_HAS_EXCEPTIONS
-namespace edit_distance {
// Returns the optimal edits to go from 'left' to 'right'.
// All edits cost the same, with replace having lower priority than
-// add/remove.
-// Simple implementation of the Wagner-Fischer algorithm.
-// See http://en.wikipedia.org/wiki/Wagner-Fischer_algorithm
-enum EditType { kMatch, kAdd, kRemove, kReplace };
+// add/remove. Returns an approximation of the maximum memory used in
+// 'memory_usage' if non-null.
+// Uses a Dijkstra search, with a couple of simple bells and whistles added on.
+enum EditType { kEditMatch, kEditAdd, kEditRemove, kEditReplace };
GTEST_API_ std::vector<EditType> CalculateOptimalEdits(
- const std::vector<size_t>& left, const std::vector<size_t>& right);
+ const std::vector<size_t>& left, const std::vector<size_t>& right,
+ size_t* memory_usage = NULL);
// Same as above, but the input is represented as strings.
GTEST_API_ std::vector<EditType> CalculateOptimalEdits(
@@ -179,8 +179,6 @@
const std::vector<std::string>& right,
size_t context = 2);
-} // namespace edit_distance
-
// Calculate the diff between 'left' and 'right' and return it in unified diff
// format.
// If not null, stores in 'total_line_count' the total number of lines found
diff --git a/googletest/src/gtest-all.cc b/googletest/src/gtest-all.cc
index b217a18..3363d39 100644
--- a/googletest/src/gtest-all.cc
+++ b/googletest/src/gtest-all.cc
@@ -38,10 +38,11 @@
#include "gtest/gtest.h"
// The following lines pull in the real gtest *.cc files.
-#include "src/gtest.cc"
#include "src/gtest-death-test.cc"
+#include "src/gtest-edit-distance.cc"
#include "src/gtest-filepath.cc"
#include "src/gtest-port.cc"
#include "src/gtest-printers.cc"
#include "src/gtest-test-part.cc"
#include "src/gtest-typed-test.cc"
+#include "src/gtest.cc"
diff --git a/googletest/src/gtest-edit-distance.cc b/googletest/src/gtest-edit-distance.cc
new file mode 100644
index 0000000..331a3b9
--- /dev/null
+++ b/googletest/src/gtest-edit-distance.cc
@@ -0,0 +1,507 @@
+// Copyright 2018, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// Internal helper functions for finding optimal edit transformations
+// between strings.
+
+#include "gtest/gtest.h"
+
+#include <functional>
+#include <list>
+#include <ostream> // NOLINT
+#include <queue>
+#include <vector>
+
+namespace testing {
+namespace internal {
+namespace {
+
+// The following implement data structures and code for a Dijkstra-search
+// based implementation of optimal edit distance.
+
+// Posible states a node can be in. Either a node is unsettled (it hasn't been
+// drawn from the priority queue yet), or it is settled and a back-link to its
+// parent node is fixed.
+enum EditSearchState {
+ kUnsettled,
+ kMatchParent,
+ kAddParent,
+ kRemoveParent,
+ kReplaceParent
+};
+
+// Custom container for search states. This is smaller and faster than a hash
+// map, because the used states are dense along diagonals.
+// Specifically, each state requires only 1 byte, whereas a hash_map would
+// require storing the key, which would come to at least 8 bytes. std::map has
+// an extra 32 bytes per node (3 pointers + 1 byte, padded), so even though
+// there are circumstances where this class can have kBlockSize overhead per
+// state, on average it does better than 40 bytes of overhead per state.
+// In addition, in unopt builds (the usual way tests are run) the fewer
+// allocations + better locality has this method running 10-50x faster than
+// std::map for inputs that are large enough to measure.
+class EditSearchMap {
+ public:
+ EditSearchMap(size_t left_size, size_t right_size)
+ : left_size_(left_size), right_size_(right_size) {
+ GTEST_CHECK_(left_size_ == left_size && right_size_ == right_size)
+ << "Overflow in size: Arguments too large";
+ }
+
+ // Gets a mutable reference to a state - this is actually of type
+ // EditSearchState - inserting if it does not exist.
+ unsigned char& insert(UInt32 left, UInt32 right) {
+ std::vector<UInt32>* vec;
+ size_t index1;
+ size_t index2;
+ if (left > right) {
+ vec = &left_nodes_;
+ index1 = left - right - 1;
+ index2 = right;
+ } else {
+ vec = &right_nodes_;
+ index1 = right - left;
+ index2 = left;
+ }
+ if (vec->size() <= index1) {
+ GTEST_CHECK_(vec->size() == index1)
+ << "Array diagonals should only grow by one " << vec->size() << " vs "
+ << index1;
+ vec->push_back(block_indices_.size());
+ // Round up
+ block_indices_.resize(
+ block_indices_.size() +
+ (DiagonalLength(left, right) + kBlockSize - 1) / kBlockSize,
+ kUnallocatedBlock);
+ }
+ const size_t bucket = index2 / kBlockSize;
+ const size_t pos_in_bucket = index2 % kBlockSize;
+ UInt32& level2 = block_indices_[(*vec)[index1] + bucket];
+ if (level2 == kUnallocatedBlock) {
+ level2 = nodes_.size();
+ size_t diagonal_length = DiagonalLength(left, right);
+ GTEST_CHECK_(diagonal_length > index2)
+ << diagonal_length << " " << index2;
+ size_t block_size = kBlockSize;
+ if (diagonal_length / kBlockSize == bucket) {
+ // We can never get here if diagonal_length is a multiple of
+ // kBlockSize, which is what we want, since this would evaluate to 0.
+ block_size = diagonal_length % kBlockSize;
+ }
+ nodes_.resize(nodes_.size() + block_size);
+ }
+ return nodes_[level2 + pos_in_bucket];
+ }
+
+ size_t MemoryUsage() const {
+ return nodes_.capacity() +
+ sizeof(UInt32) * (left_nodes_.capacity() + right_nodes_.capacity() +
+ block_indices_.capacity());
+ }
+
+ private:
+ enum { kBlockSize = 1024, kUnallocatedBlock = 0xFFFFFFFFul };
+
+ size_t DiagonalLength(UInt32 left, UInt32 right) const {
+ return std::min(left_size_ - left, right_size_ - right) +
+ (left < right ? left : right);
+ }
+
+ // The state space is conceptually a left_size_ by right_size_ sparse matrix
+ // of EditSearchStates. However, due to the access pattern of the search, it
+ // is much better to store the nodes per diagonal rather than per row.
+ UInt32 left_size_;
+ UInt32 right_size_;
+ // The nodes are stored by diagonals, split in two: Those to the left of the
+ // main diagonal are in left_nodes_, and everything else is in right_nodes_.
+ // The values are indices into block_indices_.
+ std::vector<UInt32> left_nodes_;
+ std::vector<UInt32> right_nodes_;
+ // Every entry here is an offset into the beginning of a kBlockSize-sized
+ // block in nodes_. An entire diagonal is allocated together here; for a
+ // diagonal of length <= kBlockSize, that's just a single entry, but for
+ // longer diagonals multiple contiguous index entries will be reserved at
+ // once. Unused entries will be assigned kUnallocatedBlock; this
+ // double-indirect scheme is used to save memory in the cases when an entire
+ // diagonal isn't needed.
+ std::vector<UInt32> block_indices_;
+ // This stores the actual EditSearchState data, pointed to by block_indices_.
+ std::vector<unsigned char> nodes_;
+};
+
+struct EditHeapEntry {
+ EditHeapEntry(UInt32 l, UInt32 r, UInt64 c, EditSearchState s)
+ : left(l), right(r), cost(c), state(s) {}
+
+ UInt32 left;
+ UInt32 right;
+ UInt64 cost : 61;
+ // The state that the node will get when this entry is settled. Therefore,
+ // this can never be kUnsettled.
+ UInt64 state : 3;
+
+ bool operator>(const EditHeapEntry& other) const { return cost > other.cost; }
+};
+
+// Need a min-queue, so invert the comparator.
+typedef std::priority_queue<EditHeapEntry, std::vector<EditHeapEntry>,
+ std::greater<EditHeapEntry>>
+ EditHeap;
+
+} // namespace
+
+std::vector<EditType> CalculateOptimalEdits(const std::vector<size_t>& left,
+ const std::vector<size_t>& right,
+ size_t* memory_usage) {
+ const UInt64 kBaseCost = 100000;
+ // We make replace a little more expensive than add/remove to lower
+ // their priority.
+ const UInt64 kReplaceCost = 100001;
+ // In the common case where the vectors are the same (or almost the same)
+ // size, we know that an add will have to be followed by some later remove
+ // (or vice versa) in order to get the lengths to balance. We "borrow" some
+ // of the cost of the later operation and bring it forward into the earlier
+ // operation, to increase the cost of exploring (usually fruitlessly) around
+ // the beginning of the graph.
+ // However, there is a trade-off: This cheapens the cost of exploring around
+ // the beginning of the graph (in one direction) when the vectors are
+ // unequal in length. So we don't steal *all* the cost.
+ // You can view this as a form of A*, using an admissable heuristic that has
+ // been re-cast as a cost function that can be used in Dijkstra.
+ const UInt64 kTowardsGoalCost = 50003;
+ const UInt64 kAwayFromGoalCost = 2 * kBaseCost - kTowardsGoalCost;
+
+ EditSearchMap node_map(left.size() + 1, right.size() + 1);
+ EditHeap heap;
+ heap.push(EditHeapEntry(0, 0, 0, kReplaceParent));
+
+ while (!heap.empty()) {
+ const EditHeapEntry current_entry = heap.top();
+ heap.pop();
+
+ UInt32 left_pos = current_entry.left;
+ UInt32 right_pos = current_entry.right;
+ unsigned char& current_state = node_map.insert(left_pos, right_pos);
+ if (current_state != kUnsettled) {
+ // Node was already settled by a previous entry in the priority queue,
+ // this is a suboptimal path that should be ignored.
+ continue;
+ }
+ current_state = current_entry.state;
+
+ if (left_pos == left.size() && right_pos == right.size()) {
+ // This is the normal exit point; if we terminate due to the heap being
+ // empty, we'll fail a check later.
+ break;
+ }
+
+ // Special case: Since the cost of a match is zero, we can immediately
+ // settle the new node without putting it in the queue, since nothing can
+ // have a smaller cost than it. Furthermore, we don't need to relax the
+ // other two edges, since we know we don't need them: Any path from this
+ // node that would use them has an path via the match that is at least as
+ // cheap. Together, this means we can loop here until we stop matching.
+ while (left_pos < left.size() && right_pos < right.size() &&
+ left[left_pos] == right[right_pos]) {
+ left_pos++;
+ right_pos++;
+ unsigned char& fast_forward_state = node_map.insert(left_pos, right_pos);
+ if (fast_forward_state != kUnsettled) {
+ // The search reached around and settled this node before settling the
+ // base node. This means we're completely done with this iteration;
+ // abort to the outer loop.
+ goto outer_loop_bottom;
+ // Otherwise, when can settle this node, even if it was created from
+ // another state - we know the cost of settling it now is optimal.
+ }
+ fast_forward_state = kMatchParent;
+ }
+
+ // Relax adjacent nodes. We have no way to find or lower the cost of
+ // existing entries in the heap, so we just push new entries and throw
+ // them out at the top if the node is already settled. We *could* check to
+ // see if they're already settled before pushing, but it turns out to be
+ // ~not any faster, and more complicated to do so.
+ //
+ // If we're at an edge, there's only one node to relax.
+ if (left_pos >= left.size()) {
+ if (right_pos >= right.size()) {
+ break; // Can happen due to the fast-path loop above.
+ }
+ heap.push(EditHeapEntry(left_pos, right_pos + 1,
+ current_entry.cost + kTowardsGoalCost,
+ kAddParent));
+ continue;
+ }
+ if (right_pos >= right.size()) {
+ heap.push(EditHeapEntry(left_pos + 1, right_pos,
+ current_entry.cost + kTowardsGoalCost,
+ kRemoveParent));
+ continue;
+ }
+ // General case: Relax 3 edges.
+ heap.push(EditHeapEntry(
+ left_pos, right_pos + 1,
+ current_entry.cost + (right.size() + left_pos > right_pos + left.size()
+ ? kTowardsGoalCost
+ : kAwayFromGoalCost),
+ kAddParent));
+ heap.push(EditHeapEntry(
+ left_pos + 1, right_pos,
+ current_entry.cost + (right.size() + left_pos < right_pos + left.size()
+ ? kTowardsGoalCost
+ : kAwayFromGoalCost),
+ kRemoveParent));
+ heap.push(EditHeapEntry(left_pos + 1, right_pos + 1,
+ current_entry.cost + kReplaceCost, kReplaceParent));
+ outer_loop_bottom : {} // Need the curlies to form a statement.
+ }
+
+ // Reconstruct the best path. We do it in reverse order.
+ std::vector<EditType> best_path;
+ UInt32 left_pos = left.size();
+ UInt32 right_pos = right.size();
+ while (left_pos != 0 || right_pos != 0) {
+ GTEST_CHECK_(left_pos <= left.size() && right_pos <= right.size());
+ // The node must already exist, but if it somehow doesn't, it will be
+ // added as kUnsettled, which will crash below.
+ const unsigned char state = node_map.insert(left_pos, right_pos);
+ switch (state) {
+ case kAddParent:
+ right_pos--;
+ break;
+ case kRemoveParent:
+ left_pos--;
+ break;
+ case kMatchParent:
+ case kReplaceParent:
+ left_pos--;
+ right_pos--;
+ break;
+ default:
+ GTEST_LOG_(FATAL) << "Unsettled node at " << left_pos << ","
+ << right_pos;
+ }
+ best_path.push_back(static_cast<EditType>(state - 1));
+ }
+ std::reverse(best_path.begin(), best_path.end());
+ if (memory_usage != NULL) {
+ *memory_usage = node_map.MemoryUsage();
+ }
+ return best_path;
+}
+
+namespace {
+
+// Helper class to convert string into ids with deduplication.
+class InternalStrings {
+ public:
+ size_t GetId(const std::string* str) {
+ IdMap::iterator it = ids_.find(str);
+ if (it != ids_.end()) return it->second;
+ size_t id = ids_.size();
+ return ids_[str] = id;
+ }
+
+ private:
+ struct IdMapCmp {
+ bool operator()(const std::string* first, const std::string* second) const {
+ return *first < *second;
+ }
+ };
+ typedef std::map<const std::string*, size_t, IdMapCmp> IdMap;
+ IdMap ids_;
+};
+
+} // namespace
+
+std::vector<EditType> CalculateOptimalEdits(
+ const std::vector<std::string>& left,
+ const std::vector<std::string>& right) {
+ std::vector<size_t> left_ids, right_ids;
+ {
+ InternalStrings intern_table;
+ for (size_t i = 0; i < left.size(); ++i) {
+ left_ids.push_back(intern_table.GetId(&left[i]));
+ }
+ for (size_t i = 0; i < right.size(); ++i) {
+ right_ids.push_back(intern_table.GetId(&right[i]));
+ }
+ }
+ return CalculateOptimalEdits(left_ids, right_ids);
+}
+
+namespace {
+
+// Helper class that holds the state for one hunk and prints it out to the
+// stream.
+// It reorders adds/removes when possible to group all removes before all
+// adds. It also adds the hunk header before printing into the stream.
+class Hunk {
+ public:
+ Hunk(size_t left_start, size_t right_start)
+ : left_start_(left_start),
+ right_start_(right_start),
+ adds_(),
+ removes_(),
+ common_() {}
+
+ void PushLine(char edit, const char* line) {
+ switch (edit) {
+ case ' ':
+ ++common_;
+ FlushEdits();
+ hunk_.push_back(std::make_pair(' ', line));
+ break;
+ case '-':
+ ++removes_;
+ hunk_removes_.push_back(std::make_pair('-', line));
+ break;
+ case '+':
+ ++adds_;
+ hunk_adds_.push_back(std::make_pair('+', line));
+ break;
+ }
+ }
+
+ void PrintTo(std::ostream* os) {
+ PrintHeader(os);
+ FlushEdits();
+ for (std::list<std::pair<char, const char*> >::const_iterator it =
+ hunk_.begin();
+ it != hunk_.end(); ++it) {
+ *os << it->first << it->second << "\n";
+ }
+ }
+
+ bool has_edits() const { return adds_ || removes_; }
+
+ private:
+ void FlushEdits() {
+ hunk_.splice(hunk_.end(), hunk_removes_);
+ hunk_.splice(hunk_.end(), hunk_adds_);
+ }
+
+ // Print a unified diff header for one hunk.
+ // The format is
+ // "@@ -<left_start>,<left_length> +<right_start>,<right_length> @@"
+ // where the left/right parts are omitted if unnecessary.
+ void PrintHeader(std::ostream* ss) const {
+ *ss << "@@ ";
+ if (removes_) {
+ *ss << "-" << left_start_ << "," << (removes_ + common_);
+ }
+ if (removes_ && adds_) {
+ *ss << " ";
+ }
+ if (adds_) {
+ *ss << "+" << right_start_ << "," << (adds_ + common_);
+ }
+ *ss << " @@\n";
+ }
+
+ size_t left_start_, right_start_;
+ size_t adds_, removes_, common_;
+ std::list<std::pair<char, const char*> > hunk_, hunk_adds_, hunk_removes_;
+};
+
+} // namespace
+
+// Create a list of diff hunks in Unified diff format.
+// Each hunk has a header generated by PrintHeader above plus a body with
+// lines prefixed with ' ' for no change, '-' for deletion and '+' for
+// addition.
+// 'context' represents the desired unchanged prefix/suffix around the diff.
+// If two hunks are close enough that their contexts overlap, then they are
+// joined into one hunk.
+std::string CreateUnifiedDiff(const std::vector<std::string>& left,
+ const std::vector<std::string>& right,
+ size_t context) {
+ const std::vector<EditType> edits = CalculateOptimalEdits(left, right);
+
+ size_t l_i = 0, r_i = 0, edit_i = 0;
+ std::stringstream ss;
+ while (edit_i < edits.size()) {
+ // Find first edit.
+ while (edit_i < edits.size() && edits[edit_i] == kEditMatch) {
+ ++l_i;
+ ++r_i;
+ ++edit_i;
+ }
+
+ // Find the first line to include in the hunk.
+ const size_t prefix_context = std::min(l_i, context);
+ Hunk hunk(l_i - prefix_context + 1, r_i - prefix_context + 1);
+ for (size_t i = prefix_context; i > 0; --i) {
+ hunk.PushLine(' ', left[l_i - i].c_str());
+ }
+
+ // Iterate the edits until we found enough suffix for the hunk or the input
+ // is over.
+ size_t n_suffix = 0;
+ for (; edit_i < edits.size(); ++edit_i) {
+ if (n_suffix >= context) {
+ // Continue only if the next hunk is very close.
+ std::vector<EditType>::const_iterator it = edits.begin() + edit_i;
+ while (it != edits.end() && *it == kEditMatch) ++it;
+ if (it == edits.end() || (it - edits.begin()) - edit_i >= context) {
+ // There is no next edit or it is too far away.
+ break;
+ }
+ }
+
+ EditType edit = edits[edit_i];
+ // Reset count when a non match is found.
+ n_suffix = edit == kEditMatch ? n_suffix + 1 : 0;
+
+ if (edit == kEditMatch || edit == kEditRemove || edit == kEditReplace) {
+ hunk.PushLine(edit == kEditMatch ? ' ' : '-', left[l_i].c_str());
+ }
+ if (edit == kEditAdd || edit == kEditReplace) {
+ hunk.PushLine('+', right[r_i].c_str());
+ }
+
+ // Advance indices, depending on edit type.
+ l_i += edit != kEditAdd;
+ r_i += edit != kEditRemove;
+ }
+
+ if (!hunk.has_edits()) {
+ // We are done. We don't want this hunk.
+ break;
+ }
+
+ hunk.PrintTo(&ss);
+ }
+ return ss.str();
+}
+
+} // namespace internal
+} // namespace testing
diff --git a/googletest/src/gtest.cc b/googletest/src/gtest.cc
index 9796637..ba706c1 100644
--- a/googletest/src/gtest.cc
+++ b/googletest/src/gtest.cc
@@ -46,7 +46,6 @@
#include <algorithm>
#include <iomanip>
#include <limits>
-#include <list>
#include <map>
#include <ostream> // NOLINT
#include <sstream>
@@ -1068,246 +1067,6 @@
namespace internal {
-namespace edit_distance {
-std::vector<EditType> CalculateOptimalEdits(const std::vector<size_t>& left,
- const std::vector<size_t>& right) {
- std::vector<std::vector<double> > costs(
- left.size() + 1, std::vector<double>(right.size() + 1));
- std::vector<std::vector<EditType> > best_move(
- left.size() + 1, std::vector<EditType>(right.size() + 1));
-
- // Populate for empty right.
- for (size_t l_i = 0; l_i < costs.size(); ++l_i) {
- costs[l_i][0] = static_cast<double>(l_i);
- best_move[l_i][0] = kRemove;
- }
- // Populate for empty left.
- for (size_t r_i = 1; r_i < costs[0].size(); ++r_i) {
- costs[0][r_i] = static_cast<double>(r_i);
- best_move[0][r_i] = kAdd;
- }
-
- for (size_t l_i = 0; l_i < left.size(); ++l_i) {
- for (size_t r_i = 0; r_i < right.size(); ++r_i) {
- if (left[l_i] == right[r_i]) {
- // Found a match. Consume it.
- costs[l_i + 1][r_i + 1] = costs[l_i][r_i];
- best_move[l_i + 1][r_i + 1] = kMatch;
- continue;
- }
-
- const double add = costs[l_i + 1][r_i];
- const double remove = costs[l_i][r_i + 1];
- const double replace = costs[l_i][r_i];
- if (add < remove && add < replace) {
- costs[l_i + 1][r_i + 1] = add + 1;
- best_move[l_i + 1][r_i + 1] = kAdd;
- } else if (remove < add && remove < replace) {
- costs[l_i + 1][r_i + 1] = remove + 1;
- best_move[l_i + 1][r_i + 1] = kRemove;
- } else {
- // We make replace a little more expensive than add/remove to lower
- // their priority.
- costs[l_i + 1][r_i + 1] = replace + 1.00001;
- best_move[l_i + 1][r_i + 1] = kReplace;
- }
- }
- }
-
- // Reconstruct the best path. We do it in reverse order.
- std::vector<EditType> best_path;
- for (size_t l_i = left.size(), r_i = right.size(); l_i > 0 || r_i > 0;) {
- EditType move = best_move[l_i][r_i];
- best_path.push_back(move);
- l_i -= move != kAdd;
- r_i -= move != kRemove;
- }
- std::reverse(best_path.begin(), best_path.end());
- return best_path;
-}
-
-namespace {
-
-// Helper class to convert string into ids with deduplication.
-class InternalStrings {
- public:
- size_t GetId(const std::string& str) {
- IdMap::iterator it = ids_.find(str);
- if (it != ids_.end()) return it->second;
- size_t id = ids_.size();
- return ids_[str] = id;
- }
-
- private:
- typedef std::map<std::string, size_t> IdMap;
- IdMap ids_;
-};
-
-} // namespace
-
-std::vector<EditType> CalculateOptimalEdits(
- const std::vector<std::string>& left,
- const std::vector<std::string>& right) {
- std::vector<size_t> left_ids, right_ids;
- {
- InternalStrings intern_table;
- for (size_t i = 0; i < left.size(); ++i) {
- left_ids.push_back(intern_table.GetId(left[i]));
- }
- for (size_t i = 0; i < right.size(); ++i) {
- right_ids.push_back(intern_table.GetId(right[i]));
- }
- }
- return CalculateOptimalEdits(left_ids, right_ids);
-}
-
-namespace {
-
-// Helper class that holds the state for one hunk and prints it out to the
-// stream.
-// It reorders adds/removes when possible to group all removes before all
-// adds. It also adds the hunk header before printint into the stream.
-class Hunk {
- public:
- Hunk(size_t left_start, size_t right_start)
- : left_start_(left_start),
- right_start_(right_start),
- adds_(),
- removes_(),
- common_() {}
-
- void PushLine(char edit, const char* line) {
- switch (edit) {
- case ' ':
- ++common_;
- FlushEdits();
- hunk_.push_back(std::make_pair(' ', line));
- break;
- case '-':
- ++removes_;
- hunk_removes_.push_back(std::make_pair('-', line));
- break;
- case '+':
- ++adds_;
- hunk_adds_.push_back(std::make_pair('+', line));
- break;
- }
- }
-
- void PrintTo(std::ostream* os) {
- PrintHeader(os);
- FlushEdits();
- for (std::list<std::pair<char, const char*> >::const_iterator it =
- hunk_.begin();
- it != hunk_.end(); ++it) {
- *os << it->first << it->second << "\n";
- }
- }
-
- bool has_edits() const { return adds_ || removes_; }
-
- private:
- void FlushEdits() {
- hunk_.splice(hunk_.end(), hunk_removes_);
- hunk_.splice(hunk_.end(), hunk_adds_);
- }
-
- // Print a unified diff header for one hunk.
- // The format is
- // "@@ -<left_start>,<left_length> +<right_start>,<right_length> @@"
- // where the left/right parts are omitted if unnecessary.
- void PrintHeader(std::ostream* ss) const {
- *ss << "@@ ";
- if (removes_) {
- *ss << "-" << left_start_ << "," << (removes_ + common_);
- }
- if (removes_ && adds_) {
- *ss << " ";
- }
- if (adds_) {
- *ss << "+" << right_start_ << "," << (adds_ + common_);
- }
- *ss << " @@\n";
- }
-
- size_t left_start_, right_start_;
- size_t adds_, removes_, common_;
- std::list<std::pair<char, const char*> > hunk_, hunk_adds_, hunk_removes_;
-};
-
-} // namespace
-
-// Create a list of diff hunks in Unified diff format.
-// Each hunk has a header generated by PrintHeader above plus a body with
-// lines prefixed with ' ' for no change, '-' for deletion and '+' for
-// addition.
-// 'context' represents the desired unchanged prefix/suffix around the diff.
-// If two hunks are close enough that their contexts overlap, then they are
-// joined into one hunk.
-std::string CreateUnifiedDiff(const std::vector<std::string>& left,
- const std::vector<std::string>& right,
- size_t context) {
- const std::vector<EditType> edits = CalculateOptimalEdits(left, right);
-
- size_t l_i = 0, r_i = 0, edit_i = 0;
- std::stringstream ss;
- while (edit_i < edits.size()) {
- // Find first edit.
- while (edit_i < edits.size() && edits[edit_i] == kMatch) {
- ++l_i;
- ++r_i;
- ++edit_i;
- }
-
- // Find the first line to include in the hunk.
- const size_t prefix_context = std::min(l_i, context);
- Hunk hunk(l_i - prefix_context + 1, r_i - prefix_context + 1);
- for (size_t i = prefix_context; i > 0; --i) {
- hunk.PushLine(' ', left[l_i - i].c_str());
- }
-
- // Iterate the edits until we found enough suffix for the hunk or the input
- // is over.
- size_t n_suffix = 0;
- for (; edit_i < edits.size(); ++edit_i) {
- if (n_suffix >= context) {
- // Continue only if the next hunk is very close.
- std::vector<EditType>::const_iterator it = edits.begin() + edit_i;
- while (it != edits.end() && *it == kMatch) ++it;
- if (it == edits.end() || (it - edits.begin()) - edit_i >= context) {
- // There is no next edit or it is too far away.
- break;
- }
- }
-
- EditType edit = edits[edit_i];
- // Reset count when a non match is found.
- n_suffix = edit == kMatch ? n_suffix + 1 : 0;
-
- if (edit == kMatch || edit == kRemove || edit == kReplace) {
- hunk.PushLine(edit == kMatch ? ' ' : '-', left[l_i].c_str());
- }
- if (edit == kAdd || edit == kReplace) {
- hunk.PushLine('+', right[r_i].c_str());
- }
-
- // Advance indices, depending on edit type.
- l_i += edit != kAdd;
- r_i += edit != kRemove;
- }
-
- if (!hunk.has_edits()) {
- // We are done. We don't want this hunk.
- break;
- }
-
- hunk.PrintTo(&ss);
- }
- return ss.str();
-}
-
-} // namespace edit_distance
-
namespace {
// The string representation of the values received in EqFailure() are already
@@ -1379,8 +1138,7 @@
const std::vector<std::string> rhs_lines =
SplitEscapedString(rhs_value);
if (lhs_lines.size() > 1 || rhs_lines.size() > 1) {
- msg << "\nWith diff:\n"
- << edit_distance::CreateUnifiedDiff(lhs_lines, rhs_lines);
+ msg << "\nWith diff:\n" << CreateUnifiedDiff(lhs_lines, rhs_lines);
}
}
diff --git a/googletest/test/gtest_unittest.cc b/googletest/test/gtest_unittest.cc
index f7213fb..7f6a2ac 100644
--- a/googletest/test/gtest_unittest.cc
+++ b/googletest/test/gtest_unittest.cc
@@ -215,6 +215,7 @@
using testing::GTEST_FLAG(throw_on_failure);
using testing::IsNotSubstring;
using testing::IsSubstring;
+using testing::kMaxStackTraceDepth;
using testing::Message;
using testing::ScopedFakeTestPartResultReporter;
using testing::StaticAssertTypeEq;
@@ -234,16 +235,18 @@
using testing::internal::AppendUserMessage;
using testing::internal::ArrayAwareFind;
using testing::internal::ArrayEq;
+using testing::internal::CalculateOptimalEdits;
using testing::internal::CodePointToUtf8;
using testing::internal::CompileAssertTypesEqual;
using testing::internal::CopyArray;
using testing::internal::CountIf;
+using testing::internal::CreateUnifiedDiff;
+using testing::internal::EditType;
using testing::internal::EqFailure;
using testing::internal::FloatingPoint;
using testing::internal::ForEach;
using testing::internal::FormatEpochTimeInMillisAsIso8601;
using testing::internal::FormatTimeInMillisAsSeconds;
-using testing::internal::GTestFlagSaver;
using testing::internal::GetCurrentOsStackTraceExceptTop;
using testing::internal::GetElementOr;
using testing::internal::GetNextRandomSeed;
@@ -252,6 +255,7 @@
using testing::internal::GetTimeInMillis;
using testing::internal::GetTypeId;
using testing::internal::GetUnitTestImpl;
+using testing::internal::GTestFlagSaver;
using testing::internal::ImplicitlyConvertible;
using testing::internal::Int32;
using testing::internal::Int32FromEnvOrDie;
@@ -259,6 +263,8 @@
using testing::internal::IsContainer;
using testing::internal::IsContainerTest;
using testing::internal::IsNotContainer;
+using testing::internal::kMaxRandomSeed;
+using testing::internal::kTestTypeIdInGoogleTest;
using testing::internal::NativeArray;
using testing::internal::OsStackTraceGetter;
using testing::internal::OsStackTraceGetterInterface;
@@ -280,12 +286,6 @@
using testing::internal::UInt32;
using testing::internal::UnitTestImpl;
using testing::internal::WideStringToUtf8;
-using testing::internal::edit_distance::CalculateOptimalEdits;
-using testing::internal::edit_distance::CreateUnifiedDiff;
-using testing::internal::edit_distance::EditType;
-using testing::internal::kMaxRandomSeed;
-using testing::internal::kTestTypeIdInGoogleTest;
-using testing::kMaxStackTraceDepth;
#if GTEST_HAS_STREAM_REDIRECTION
using testing::internal::CaptureStdout;
@@ -3517,14 +3517,14 @@
{__LINE__, "ABCD", "abcd", "////",
"@@ -1,4 +1,4 @@\n-A\n-B\n-C\n-D\n+a\n+b\n+c\n+d\n"},
// Path finding.
- {__LINE__, "ABCDEFGH", "ABXEGH1", " -/ - +",
+ {__LINE__, "ABCDEFGH", "ABXEGH1", " /- - +",
"@@ -1,8 +1,7 @@\n A\n B\n-C\n-D\n+X\n E\n-F\n G\n H\n+1\n"},
- {__LINE__, "AAAABCCCC", "ABABCDCDC", "- / + / ",
- "@@ -1,9 +1,9 @@\n-A\n A\n-A\n+B\n A\n B\n C\n+D\n C\n-C\n+D\n C\n"},
- {__LINE__, "ABCDE", "BCDCD", "- +/",
+ {__LINE__, "AAAABCCCC", "ABABCDCDC", " -/ + / ",
+ "@@ -1,9 +1,9 @@\n A\n-A\n-A\n+B\n A\n B\n C\n+D\n C\n-C\n+D\n C\n"},
+ {__LINE__, "ABCDE", "BCDCD", "- /+",
"@@ -1,5 +1,5 @@\n-A\n B\n C\n D\n-E\n+C\n+D\n"},
- {__LINE__, "ABCDEFGHIJKL", "BCDCDEFGJKLJK", "- ++ -- ++",
- "@@ -1,4 +1,5 @@\n-A\n B\n+C\n+D\n C\n D\n"
+ {__LINE__, "ABCDEFGHIJKL", "BGDCDEFGJKLJK", "- ++ -- ++",
+ "@@ -1,4 +1,5 @@\n-A\n B\n+G\n+D\n C\n D\n"
"@@ -6,7 +7,7 @@\n F\n G\n-H\n-I\n J\n K\n L\n+J\n+K\n"},
{}};
for (const Case* c = kCases; c->left; ++c) {
@@ -3542,6 +3542,57 @@
}
}
+// Tests that we can run CalculateOptimalEdits for a large vector, i.e. we can
+// compute diffs for large strings.
+TEST(EditDistance, LargeVectorWithDiffs) {
+ const int kSize = 300000;
+ std::vector<size_t> left;
+ std::vector<size_t> right;
+ std::vector<EditType> expected(kSize, testing::internal::kEditMatch);
+
+ left.reserve(kSize);
+ right.reserve(kSize);
+ for (int i = 0; i < kSize; ++i) {
+ // Make the contents of the vectors unique. This greatly speeds up
+ // the algorithm, since it doesn't spend time finding matches for
+ // different alignments.
+ left.push_back(i);
+ right.push_back(i);
+ }
+
+ for (int i = 0; i < 10; ++i) {
+ right[i] = kSize + i;
+ expected[i] = testing::internal::kEditReplace;
+ right[kSize - i - 1] = kSize * 2 + i;
+ expected[kSize - i - 1] = testing::internal::kEditReplace;
+ }
+ size_t memory_usage;
+ EXPECT_EQ(CalculateOptimalEdits(left, right, &memory_usage), expected);
+ EXPECT_GT(memory_usage, kSize);
+ EXPECT_LT(memory_usage, kSize * 2);
+}
+
+// Tests that we can run CalculateOptimalEdits for two vectors N and M, where
+// M = N plus additional junk at the end. The current algorithm only does O(M)
+// "real" work in this case, but allocates some extra memory. We test that this
+// is still fast enough for common cases, and we aren't allocating an
+// excessive amount of extra memory.
+TEST(EditDistance, LargeVectorWithTrailingJunk) {
+ const int kSize = 200000;
+ const int kAdditionalSize = 2000;
+ std::vector<size_t> left(kSize, 0);
+ std::vector<size_t> right(kSize + kAdditionalSize, 0);
+ std::vector<EditType> expected(kSize + kAdditionalSize,
+ testing::internal::kEditMatch);
+ for (int i = 0; i < kAdditionalSize; ++i) {
+ expected[i + kSize] = testing::internal::kEditAdd;
+ }
+ size_t memory_usage;
+ EXPECT_EQ(CalculateOptimalEdits(left, right, &memory_usage), expected);
+ EXPECT_GT(memory_usage, kSize);
+ EXPECT_LT(memory_usage, 6000000);
+}
+
// Tests EqFailure(), used for implementing *EQ* assertions.
TEST(AssertionTest, EqFailure) {
const std::string foo_val("5"), bar_val("6");
