SampleSet -> HistogramSamples (will be reused by SparseHistogram)

base/metrics/histogram_unittest.cc

Index: base/metrics/histogram_unittest.cc
===================================================================
--- base/metrics/histogram_unittest.cc	(revision 152603)
+++ base/metrics/histogram_unittest.cc	(working copy)
@@ -4,6 +4,7 @@
 
 // Test of Histogram class
 
+#include <climits>
 #include <algorithm>
 #include <vector>
 
@@ -19,6 +20,237 @@
 
 namespace base {
 
+TEST(BucketHistogramSamplesTest, AccumulateTest) {
+  // Custom buckets: [1, 5) [5, 10)
+  BucketRanges ranges(3);
+  ranges.set_range(0, 1);
+  ranges.set_range(1, 5);
+  ranges.set_range(2, 10);
+  BucketHistogramSamples samples(&ranges);
+
+  samples.Accumulate(1, 200);
+  samples.Accumulate(2, -300);
+  EXPECT_EQ(-100, samples.GetCountFromBucketIndex(0));
+
+  samples.Accumulate(5, 200);
+  EXPECT_EQ(200, samples.GetCountFromBucketIndex(1));
+
+  EXPECT_EQ(600, samples.sum());
+  EXPECT_EQ(100, samples.redundant_count());
+  EXPECT_EQ(samples.TotalCount(), samples.redundant_count());
+
+  samples.Accumulate(5, -100);
+  EXPECT_EQ(100, samples.GetCountFromBucketIndex(1));
+
+  EXPECT_EQ(100, samples.sum());
+  EXPECT_EQ(0, samples.redundant_count());
+  EXPECT_EQ(samples.TotalCount(), samples.redundant_count());
+}
+
+TEST(BucketHistogramSamplesDeathTest, BucketIndexTest) {
+  // 8 buckets with exponential layout:
+  // [0, 1) [1, 2) [2, 4) [4, 8) [8, 16) [16, 32) [32, 64) [64, INT_MAX)
+  BucketRanges ranges(9);
+  Histogram::InitializeBucketRanges(1, 64, 8, &ranges);
+  BucketHistogramSamples samples(&ranges);
+
+  // Normal case
+  samples.Accumulate(0, 1);
+  samples.Accumulate(3, 2);
+  samples.Accumulate(64, 3);
+  EXPECT_EQ(1, samples.GetCount(0));
+  EXPECT_EQ(2, samples.GetCount(2));
+  EXPECT_EQ(3, samples.GetCount(65));
+
+  // Extreme case.
+  EXPECT_DEATH(samples.Accumulate(INT_MIN, 100), "");
+  EXPECT_DEATH(samples.Accumulate(-1, 100), "");
+  EXPECT_DEATH(samples.Accumulate(INT_MAX, 100), "");
+
+  // Custom buckets: [1, 5) [5, 10)
+  // Note, this is not a valid BucketRanges for Histogram because it does not
+  // have overflow buckets.
+  BucketRanges ranges2(3);
+  ranges2.set_range(0, 1);
+  ranges2.set_range(1, 5);
+  ranges2.set_range(2, 10);
+  BucketHistogramSamples samples2(&ranges2);
+
+  // Normal case.
+  samples2.Accumulate(1, 1);
+  samples2.Accumulate(4, 1);
+  samples2.Accumulate(5, 2);
+  samples2.Accumulate(9, 2);
+  EXPECT_EQ(2, samples2.GetCount(1));
+  EXPECT_EQ(4, samples2.GetCount(5));
+
+  // Extreme case.
+  EXPECT_DEATH(samples2.Accumulate(0, 100), "");
+  EXPECT_DEATH(samples2.Accumulate(10, 100), "");
+}
+
+TEST(BucketHistogramSamplesTest, AddSubtractTest) {
+  // Custom buckets: [0, 1) [1, 2) [2, 3) [3, INT_MAX)
+  BucketRanges ranges(5);
+  ranges.set_range(0, 0);
+  ranges.set_range(1, 1);
+  ranges.set_range(2, 2);
+  ranges.set_range(3, 3);
+  ranges.set_range(4, INT_MAX);
+
+  BucketHistogramSamples samples1(&ranges);
+  samples1.Accumulate(0, 100);
+  samples1.Accumulate(2, 100);
+  samples1.Accumulate(4, 100);
+  EXPECT_EQ(600, samples1.sum());
+  EXPECT_EQ(300, samples1.TotalCount());
+  EXPECT_EQ(samples1.redundant_count(), samples1.TotalCount());
+
+  BucketHistogramSamples samples2(&ranges);
+  samples2.Accumulate(1, 200);
+  samples2.Accumulate(2, 200);
+  samples2.Accumulate(4, 200);
+  EXPECT_EQ(1400, samples2.sum());
+  EXPECT_EQ(600, samples2.TotalCount());
+  EXPECT_EQ(samples2.redundant_count(), samples2.TotalCount());
+
+  samples1.Add(samples2);
+  EXPECT_EQ(100, samples1.GetCountFromBucketIndex(0));
+  EXPECT_EQ(200, samples1.GetCountFromBucketIndex(1));
+  EXPECT_EQ(300, samples1.GetCountFromBucketIndex(2));
+  EXPECT_EQ(300, samples1.GetCountFromBucketIndex(3));
+  EXPECT_EQ(2000, samples1.sum());
+  EXPECT_EQ(900, samples1.TotalCount());
+  EXPECT_EQ(samples1.redundant_count(), samples1.TotalCount());
+
+  samples1.Subtract(samples2);
+  EXPECT_EQ(100, samples1.GetCountFromBucketIndex(0));
+  EXPECT_EQ(0, samples1.GetCountFromBucketIndex(1));
+  EXPECT_EQ(100, samples1.GetCountFromBucketIndex(2));
+  EXPECT_EQ(100, samples1.GetCountFromBucketIndex(3));
+  EXPECT_EQ(600, samples1.sum());
+  EXPECT_EQ(300, samples1.TotalCount());
+  EXPECT_EQ(samples1.redundant_count(), samples1.TotalCount());
+}
+
+TEST(BucketHistogramSamplesDeathTest, AddSubtractBucketNotMatchTest) {
+  // Custom buckets 1: [1, 3) [3, 5)
+  BucketRanges ranges1(3);
+  ranges1.set_range(0, 1);
+  ranges1.set_range(1, 3);
+  ranges1.set_range(2, 5);
+  BucketHistogramSamples samples1(&ranges1);
+
+  // Custom buckets 2: [0, 1) [1, 3) [3, 6) [6, 7)
+  BucketRanges ranges2(5);
+  ranges2.set_range(0, 0);
+  ranges2.set_range(1, 1);
+  ranges2.set_range(2, 3);
+  ranges2.set_range(3, 6);
+  ranges2.set_range(4, 7);
+  BucketHistogramSamples samples2(&ranges2);
+
+  samples2.Accumulate(1, 100);
+  samples1.Add(samples2);
+  EXPECT_EQ(100, samples1.GetCountFromBucketIndex(0));
+
+  // Extra bucket in the beginning.
+  samples2.Accumulate(0, 100);
+  EXPECT_DEATH(samples1.Add(samples2), "");
+  EXPECT_DEATH(samples1.Subtract(samples2), "");
+
+  // Extra bucket in the end.
+  samples2.Accumulate(0, -100);
+  samples2.Accumulate(6, 100);
+  EXPECT_DEATH(samples1.Add(samples2), "");
+  EXPECT_DEATH(samples1.Subtract(samples2), "");
+
+  // Bucket not match: [3, 5) VS [3, 6)
+  samples2.Accumulate(6, -100);
+  samples2.Accumulate(3, 100);
+  EXPECT_DEATH(samples1.Add(samples2), "");
+  EXPECT_DEATH(samples1.Subtract(samples2), "");
+}
+
+TEST(BucketHistogramSamplesTest, SerializationTest) {
+}
+
+TEST(BucketHistogramSamplesIteratorTest, IterateTest) {
+  BucketRanges ranges(5);
+  ranges.set_range(0, 0);
+  ranges.set_range(1, 1);
+  ranges.set_range(2, 2);
+  ranges.set_range(3, 3);
+  ranges.set_range(4, 4);
+
+  vector<HistogramBase::Count> counts(3);
+  counts[0] = 1;
+  counts[1] = 0;  // Iterator will bypass this empty bucket.
+  counts[2] = 2;
+
+  // BucketRanges can have larger size than counts.
+  BucketHistogramSamplesIterator it(&counts, &ranges);
+
+  HistogramBase::Sample min;
+  HistogramBase::Sample max;
+  HistogramBase::Count count;
+  it.Get(&min, &max, &count);
+  EXPECT_EQ(0, min);
+  EXPECT_EQ(1, max);
+  EXPECT_EQ(1, count);
+
+  it.Next();
+  it.Get(&min, &max, &count);
+  EXPECT_EQ(2, min);
+  EXPECT_EQ(3, max);
+  EXPECT_EQ(2, count);
+
+  it.Next();
+  EXPECT_TRUE(it.Done());
+
+  // Create iterator from BucketHistogramSamples.
+  BucketHistogramSamples samples(&ranges);
+  samples.Accumulate(0, 0);
+  samples.Accumulate(1, 1);
+  samples.Accumulate(2, 2);
+  samples.Accumulate(3, 3);
+  scoped_ptr<SampleCountIterator> it2 = samples.Iterator();
+
+  int i;
+  for (i = 1; !it2->Done(); i++, it2->Next()) {
+    it2->Get(&min, &max, &count);
+    EXPECT_EQ(i, min);
+    EXPECT_EQ(i + 1, max);
+    EXPECT_EQ(i, count);
+  }
+  EXPECT_EQ(4, i);
+}
+
+TEST(BucketHistogramSamplesIteratorDeathTest, IterateDoneTest) {
+  BucketRanges ranges(5);
+  ranges.set_range(0, 0);
+  ranges.set_range(1, 1);
+  ranges.set_range(2, 2);
+  ranges.set_range(3, 3);
+  ranges.set_range(4, INT_MAX);
+  BucketHistogramSamples samples(&ranges);
+
+  scoped_ptr<SampleCountIterator> it = samples.Iterator();
+
+  EXPECT_TRUE(it->Done());
+
+  HistogramBase::Sample min;
+  HistogramBase::Sample max;
+  HistogramBase::Count count;
+  EXPECT_DEATH(it->Get(&min, &max, &count), "");
+
+  EXPECT_DEATH(it->Next(), "");
+
+  samples.Accumulate(2, 100);
+  it = samples.Iterator();
+  EXPECT_FALSE(it->Done());
+}
+
 // Check for basic syntax and use.
 TEST(HistogramTest, BasicTest) {
   // Try basic construction
@@ -206,14 +438,13 @@
   histogram->Add(10000);
 
   // Verify they landed in the underflow, and overflow buckets.
-  Histogram::SampleSet sample;
-  histogram->SnapshotSample(&sample);
-  EXPECT_EQ(2, sample.counts(0));
-  EXPECT_EQ(0, sample.counts(1));
+  scoped_ptr<BucketHistogramSamples> samples = histogram->SnapshotSamples();
+  EXPECT_EQ(2, samples->GetCountFromBucketIndex(0));
+  EXPECT_EQ(0, samples->GetCountFromBucketIndex(1));
   size_t array_size = histogram->bucket_count();
   EXPECT_EQ(kBucketCount, array_size);
-  EXPECT_EQ(0, sample.counts(array_size - 2));
-  EXPECT_EQ(2, sample.counts(array_size - 1));
+  EXPECT_EQ(0, samples->GetCountFromBucketIndex(array_size - 2));
+  EXPECT_EQ(2, samples->GetCountFromBucketIndex(array_size - 1));
 
   vector<int> custom_ranges;
   custom_ranges.push_back(10);
@@ -227,15 +458,16 @@
   test_custom_histogram->Add(-50);
   test_custom_histogram->Add(100);
   test_custom_histogram->Add(1000);
+  test_custom_histogram->Add(INT_MAX);
 
   // Verify they landed in the underflow, and overflow buckets.
-  Histogram::SampleSet custom_sample;
-  test_custom_histogram->SnapshotSample(&custom_sample);
-  EXPECT_EQ(2, custom_sample.counts(0));
-  EXPECT_EQ(0, custom_sample.counts(1));
-  size_t custom_array_size = test_custom_histogram->bucket_count();
-  EXPECT_EQ(0, custom_sample.counts(custom_array_size - 2));
-  EXPECT_EQ(2, custom_sample.counts(custom_array_size - 1));
+  scoped_ptr<BucketHistogramSamples> custom_samples =
+      test_custom_histogram->SnapshotSamples();
+  EXPECT_EQ(2, custom_samples->GetCountFromBucketIndex(0));
+  EXPECT_EQ(0, custom_samples->GetCountFromBucketIndex(1));
+  size_t bucket_count = test_custom_histogram->bucket_count();
+  EXPECT_EQ(0, custom_samples->GetCountFromBucketIndex(bucket_count - 2));
+  EXPECT_EQ(3, custom_samples->GetCountFromBucketIndex(bucket_count - 1));
 }
 
 // Check to be sure samples land as expected is "correct" buckets.
@@ -253,45 +485,45 @@
   }
 
   // Check to see that the bucket counts reflect our additions.
-  Histogram::SampleSet sample;
-  histogram->SnapshotSample(&sample);
+  scoped_ptr<BucketHistogramSamples> samples = histogram->SnapshotSamples();
   for (int i = 0; i < 8; i++)
-    EXPECT_EQ(i + 1, sample.counts(i));
+    EXPECT_EQ(i + 1, samples->GetCountFromBucketIndex(i));
 }
 
 TEST(HistogramTest, CorruptSampleCounts) {
   Histogram* histogram(Histogram::FactoryGet(
       "Histogram", 1, 64, 8, Histogram::kNoFlags));  // As per header file.
 
-  EXPECT_EQ(0, histogram->sample_.redundant_count());
-  histogram->Add(20);  // Add some samples.
+  // Add some samples.
+  histogram->Add(20);
   histogram->Add(40);
-  EXPECT_EQ(2, histogram->sample_.redundant_count());
 
-  Histogram::SampleSet snapshot;
-  histogram->SnapshotSample(&snapshot);
-  EXPECT_EQ(Histogram::NO_INCONSISTENCIES, 0);
-  EXPECT_EQ(0, histogram->FindCorruption(snapshot));  // No default corruption.
-  EXPECT_EQ(2, snapshot.redundant_count());
+  scoped_ptr<BucketHistogramSamples> snapshot = histogram->SnapshotSamples();
+  EXPECT_EQ(Histogram::NO_INCONSISTENCIES,
+            histogram->FindCorruption(*snapshot));
+  EXPECT_EQ(2, snapshot->redundant_count());
+  EXPECT_EQ(2, snapshot->TotalCount());
 
-  snapshot.counts_[3] += 100;  // Sample count won't match redundant count.
-  EXPECT_EQ(Histogram::COUNT_LOW_ERROR, histogram->FindCorruption(snapshot));
-  snapshot.counts_[2] -= 200;
-  EXPECT_EQ(Histogram::COUNT_HIGH_ERROR, histogram->FindCorruption(snapshot));
+  snapshot->counts_[3] += 100;  // Sample count won't match redundant count.
+  EXPECT_EQ(Histogram::COUNT_LOW_ERROR,
+            histogram->FindCorruption(*snapshot));
+  snapshot->counts_[2] -= 200;
+  EXPECT_EQ(Histogram::COUNT_HIGH_ERROR,
+            histogram->FindCorruption(*snapshot));
 
   // But we can't spot a corruption if it is compensated for.
-  snapshot.counts_[1] += 100;
-  EXPECT_EQ(0, histogram->FindCorruption(snapshot));
+  snapshot->counts_[1] += 100;
+  EXPECT_EQ(Histogram::NO_INCONSISTENCIES,
+            histogram->FindCorruption(*snapshot));
 }
 
 TEST(HistogramTest, CorruptBucketBounds) {
   Histogram* histogram(Histogram::FactoryGet(
       "Histogram", 1, 64, 8, Histogram::kNoFlags));  // As per header file.
 
-  Histogram::SampleSet snapshot;
-  histogram->SnapshotSample(&snapshot);
-  EXPECT_EQ(Histogram::NO_INCONSISTENCIES, 0);
-  EXPECT_EQ(0, histogram->FindCorruption(snapshot));  // No default corruption.
+  scoped_ptr<BucketHistogramSamples> snapshot = histogram->SnapshotSamples();
+  EXPECT_EQ(Histogram::NO_INCONSISTENCIES,
+            histogram->FindCorruption(*snapshot));
 
   BucketRanges* bucket_ranges =
       const_cast<BucketRanges*>(histogram->bucket_ranges());
@@ -299,20 +531,20 @@
   bucket_ranges->set_range(1, bucket_ranges->range(2));
   bucket_ranges->set_range(2, tmp);
   EXPECT_EQ(Histogram::BUCKET_ORDER_ERROR | Histogram::RANGE_CHECKSUM_ERROR,
-            histogram->FindCorruption(snapshot));
+            histogram->FindCorruption(*snapshot));
 
   bucket_ranges->set_range(2, bucket_ranges->range(1));
   bucket_ranges->set_range(1, tmp);
-  EXPECT_EQ(0, histogram->FindCorruption(snapshot));
+  EXPECT_EQ(0, histogram->FindCorruption(*snapshot));
 
+  // Show that two simple changes don't offset each other
   bucket_ranges->set_range(3, bucket_ranges->range(3) + 1);
   EXPECT_EQ(Histogram::RANGE_CHECKSUM_ERROR,
-            histogram->FindCorruption(snapshot));
+            histogram->FindCorruption(*snapshot));
 
-  // Show that two simple changes don't offset each other
   bucket_ranges->set_range(4, bucket_ranges->range(4) - 1);
   EXPECT_EQ(Histogram::RANGE_CHECKSUM_ERROR,
-            histogram->FindCorruption(snapshot));
+            histogram->FindCorruption(*snapshot));
 
   // Repair histogram so that destructor won't DCHECK().
   bucket_ranges->set_range(3, bucket_ranges->range(3) - 1);