// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Histogram is an object that aggregates statistics, and can summarize them in
// various forms, including ASCII graphical, HTML, and numerically (as a
// vector of numbers corresponding to each of the aggregating buckets).
// See header file for details and examples.
#include "base/histogram.h"
#include <math.h>
#include <string>
#include "base/logging.h"
#include "base/pickle.h"
#include "base/string_util.h"
using base::TimeDelta;
typedef Histogram::Count Count;
scoped_refptr<Histogram> Histogram::FactoryGet(const std::string& name,
Sample minimum, Sample maximum, size_t bucket_count, Flags flags) {
scoped_refptr<Histogram> histogram(NULL);
// Defensive code.
if (minimum <= 0)
minimum = 1;
if (maximum >= kSampleType_MAX)
maximum = kSampleType_MAX - 1;
if (StatisticsRecorder::FindHistogram(name, &histogram)) {
DCHECK(histogram.get() != NULL);
} else {
histogram = new Histogram(name, minimum, maximum, bucket_count);
scoped_refptr<Histogram> registered_histogram(NULL);
StatisticsRecorder::FindHistogram(name, ®istered_histogram);
// Allow a NULL return to mean that the StatisticsRecorder was not started.
if (registered_histogram.get() != NULL &&
registered_histogram.get() != histogram.get())
histogram = registered_histogram;
}
DCHECK(HISTOGRAM == histogram->histogram_type());
DCHECK(histogram->HasConstructorArguments(minimum, maximum, bucket_count));
histogram->SetFlags(flags);
return histogram;
}
scoped_refptr<Histogram> Histogram::FactoryGet(const std::string& name,
base::TimeDelta minimum, base::TimeDelta maximum, size_t bucket_count,
Flags flags) {
return FactoryGet(name, minimum.InMilliseconds(), maximum.InMilliseconds(),
bucket_count, flags);
}
Histogram::Histogram(const std::string& name, Sample minimum,
Sample maximum, size_t bucket_count)
: histogram_name_(name),
declared_min_(minimum),
declared_max_(maximum),
bucket_count_(bucket_count),
flags_(kNoFlags),
ranges_(bucket_count + 1, 0),
sample_() {
Initialize();
}
Histogram::Histogram(const std::string& name, TimeDelta minimum,
TimeDelta maximum, size_t bucket_count)
: histogram_name_(name),
declared_min_(static_cast<int> (minimum.InMilliseconds())),
declared_max_(static_cast<int> (maximum.InMilliseconds())),
bucket_count_(bucket_count),
flags_(kNoFlags),
ranges_(bucket_count + 1, 0),
sample_() {
Initialize();
}
Histogram::~Histogram() {
if (StatisticsRecorder::dump_on_exit()) {
std::string output;
WriteAscii(true, "\n", &output);
LOG(INFO) << output;
}
// Just to make sure most derived class did this properly...
DCHECK(ValidateBucketRanges());
}
void Histogram::Add(int value) {
if (value >= kSampleType_MAX)
value = kSampleType_MAX - 1;
if (value < 0)
value = 0;
size_t index = BucketIndex(value);
DCHECK(value >= ranges(index));
DCHECK(value < ranges(index + 1));
Accumulate(value, 1, index);
}
void Histogram::AddSampleSet(const SampleSet& sample) {
sample_.Add(sample);
}
// The following methods provide a graphical histogram display.
void Histogram::WriteHTMLGraph(std::string* output) const {
// TBD(jar) Write a nice HTML bar chart, with divs an mouse-overs etc.
output->append("<PRE>");
WriteAscii(true, "<br>", output);
output->append("</PRE>");
}
void Histogram::WriteAscii(bool graph_it, const std::string& newline,
std::string* output) const {
// Get local (stack) copies of all effectively volatile class data so that we
// are consistent across our output activities.
SampleSet snapshot;
SnapshotSample(&snapshot);
Count sample_count = snapshot.TotalCount();
WriteAsciiHeader(snapshot, sample_count, output);
output->append(newline);
// Prepare to normalize graphical rendering of bucket contents.
double max_size = 0;
if (graph_it)
max_size = GetPeakBucketSize(snapshot);
// Calculate space needed to print bucket range numbers. Leave room to print
// nearly the largest bucket range without sliding over the histogram.
size_t largest_non_empty_bucket = bucket_count() - 1;
while (0 == snapshot.counts(largest_non_empty_bucket)) {
if (0 == largest_non_empty_bucket)
break; // All buckets are empty.
--largest_non_empty_bucket;
}
// Calculate largest print width needed for any of our bucket range displays.
size_t print_width = 1;
for (size_t i = 0; i < bucket_count(); ++i) {
if (snapshot.counts(i)) {
size_t width = GetAsciiBucketRange(i).size() + 1;
if (width > print_width)
print_width = width;
}
}
int64 remaining = sample_count;
int64 past = 0;
// Output the actual histogram graph.
for (size_t i = 0; i < bucket_count(); ++i) {
Count current = snapshot.counts(i);
if (!current && !PrintEmptyBucket(i))
continue;
remaining -= current;
std::string range = GetAsciiBucketRange(i);
output->append(range);
for (size_t j = 0; range.size() + j < print_width + 1; ++j)
output->push_back(' ');
if (0 == current && i < bucket_count() - 1 && 0 == snapshot.counts(i + 1)) {
while (i < bucket_count() - 1 && 0 == snapshot.counts(i + 1))
++i;
output->append("... ");
output->append(newline);
continue; // No reason to plot emptiness.
}
double current_size = GetBucketSize(current, i);
if (graph_it)
WriteAsciiBucketGraph(current_size, max_size, output);
WriteAsciiBucketContext(past, current, remaining, i, output);
output->append(newline);
past += current;
}
DCHECK(past == sample_count);
}
bool Histogram::ValidateBucketRanges() const {
// Standard assertions that all bucket ranges should satisfy.
DCHECK(ranges_.size() == bucket_count_ + 1);
DCHECK_EQ(0, ranges_[0]);
DCHECK(declared_min() == ranges_[1]);
DCHECK(declared_max() == ranges_[bucket_count_ - 1]);
DCHECK(kSampleType_MAX == ranges_[bucket_count_]);
return true;
}
void Histogram::Initialize() {
sample_.Resize(*this);
if (declared_min_ <= 0)
declared_min_ = 1;
if (declared_max_ >= kSampleType_MAX)
declared_max_ = kSampleType_MAX - 1;
DCHECK(declared_min_ <= declared_max_);
DCHECK_LT(1u, bucket_count_);
size_t maximal_bucket_count = declared_max_ - declared_min_ + 2;
DCHECK(bucket_count_ <= maximal_bucket_count);
DCHECK_EQ(0, ranges_[0]);
ranges_[bucket_count_] = kSampleType_MAX;
InitializeBucketRange();
DCHECK(ValidateBucketRanges());
StatisticsRecorder::Register(this);
}
// Calculate what range of values are held in each bucket.
// We have to be careful that we don't pick a ratio between starting points in
// consecutive buckets that is sooo small, that the integer bounds are the same
// (effectively making one bucket get no values). We need to avoid:
// (ranges_[i] == ranges_[i + 1]
// To avoid that, we just do a fine-grained bucket width as far as we need to
// until we get a ratio that moves us along at least 2 units at a time. From
// that bucket onward we do use the exponential growth of buckets.
void Histogram::InitializeBucketRange() {
double log_max = log(static_cast<double>(declared_max()));
double log_ratio;
double log_next;
size_t bucket_index = 1;
Sample current = declared_min();
SetBucketRange(bucket_index, current);
while (bucket_count() > ++bucket_index) {
double log_current;
log_current = log(static_cast<double>(current));
// Calculate the count'th root of the range.
log_ratio = (log_max - log_current) / (bucket_count() - bucket_index);
// See where the next bucket would start.
log_next = log_current + log_ratio;
int next;
next = static_cast<int>(floor(exp(log_next) + 0.5));
if (next > current)
current = next;
else
++current; // Just do a narrow bucket, and keep trying.
SetBucketRange(bucket_index, current);
}
DCHECK(bucket_count() == bucket_index);
}
size_t Histogram::BucketIndex(Sample value) const {
// Use simple binary search. This is very general, but there are better
// approaches if we knew that the buckets were linearly distributed.
DCHECK(ranges(0) <= value);
DCHECK(ranges(bucket_count()) > value);
size_t under = 0;
size_t over = bucket_count();
size_t mid;
do {
DCHECK(over >= under);
mid = (over + under)/2;
if (mid == under)
break;
if (ranges(mid) <= value)
under = mid;
else
over = mid;
} while (true);
DCHECK(ranges(mid) <= value && ranges(mid+1) > value);
return mid;
}
// Use the actual bucket widths (like a linear histogram) until the widths get
// over some transition value, and then use that transition width. Exponentials
// get so big so fast (and we don't expect to see a lot of entries in the large
// buckets), so we need this to make it possible to see what is going on and
// not have 0-graphical-height buckets.
double Histogram::GetBucketSize(Count current, size_t i) const {
DCHECK(ranges(i + 1) > ranges(i));
static const double kTransitionWidth = 5;
double denominator = ranges(i + 1) - ranges(i);
if (denominator > kTransitionWidth)
denominator = kTransitionWidth; // Stop trying to normalize.
return current/denominator;
}
//------------------------------------------------------------------------------
// The following two methods can be overridden to provide a thread safe
// version of this class. The cost of locking is low... but an error in each
// of these methods has minimal impact. For now, I'll leave this unlocked,
// and I don't believe I can loose more than a count or two.
// The vectors are NOT reallocated, so there is no risk of them moving around.
// Update histogram data with new sample.
void Histogram::Accumulate(Sample value, Count count, size_t index) {
// Note locking not done in this version!!!
sample_.Accumulate(value, count, index);
}
// Do a safe atomic snapshot of sample data.
// This implementation assumes we are on a safe single thread.
void Histogram::SnapshotSample(SampleSet* sample) const {
// Note locking not done in this version!!!
*sample = sample_;
}
//------------------------------------------------------------------------------
// Accessor methods
void Histogram::SetBucketRange(size_t i, Sample value) {
DCHECK(bucket_count_ > i);
ranges_[i] = value;
}
//------------------------------------------------------------------------------
// Private methods
double Histogram::GetPeakBucketSize(const SampleSet& snapshot) const {
double max = 0;
for (size_t i = 0; i < bucket_count() ; ++i) {
double current_size = GetBucketSize(snapshot.counts(i), i);
if (current_size > max)
max = current_size;
}
return max;
}
void Histogram::WriteAsciiHeader(const SampleSet& snapshot,
Count sample_count,
std::string* output) const {
StringAppendF(output,
"Histogram: %s recorded %d samples",
histogram_name().c_str(),
sample_count);
if (0 == sample_count) {
DCHECK_EQ(0, snapshot.sum());
} else {
double average = static_cast<float>(snapshot.sum()) / sample_count;
double variance = static_cast<float>(snapshot.square_sum())/sample_count
- average * average;
double standard_deviation = sqrt(variance);
StringAppendF(output,
", average = %.1f, standard deviation = %.1f",
average, standard_deviation);
}
if (flags_ & ~kHexRangePrintingFlag )
StringAppendF(output, " (flags = 0x%x)", flags_ & ~kHexRangePrintingFlag);
}
void Histogram::WriteAsciiBucketContext(const int64 past,
const Count current,
const int64 remaining,
const size_t i,
std::string* output) const {
double scaled_sum = (past + current + remaining) / 100.0;
WriteAsciiBucketValue(current, scaled_sum, output);
if (0 < i) {
double percentage = past / scaled_sum;
StringAppendF(output, " {%3.1f%%}", percentage);
}
}
const std::string Histogram::GetAsciiBucketRange(size_t i) const {
std::string result;
if (kHexRangePrintingFlag & flags_)
StringAppendF(&result, "%#x", ranges(i));
else
StringAppendF(&result, "%d", ranges(i));
return result;
}
void Histogram::WriteAsciiBucketValue(Count current, double scaled_sum,
std::string* output) const {
StringAppendF(output, " (%d = %3.1f%%)", current, current/scaled_sum);
}
void Histogram::WriteAsciiBucketGraph(double current_size, double max_size,
std::string* output) const {
const int k_line_length = 72; // Maximal horizontal width of graph.
int x_count = static_cast<int>(k_line_length * (current_size / max_size)
+ 0.5);
int x_remainder = k_line_length - x_count;
while (0 < x_count--)
output->append("-");
output->append("O");
while (0 < x_remainder--)
output->append(" ");
}
// static
std::string Histogram::SerializeHistogramInfo(const Histogram& histogram,
const SampleSet& snapshot) {
DCHECK(histogram.histogram_type() != NOT_VALID_IN_RENDERER);
Pickle pickle;
pickle.WriteString(histogram.histogram_name());
pickle.WriteInt(histogram.declared_min());
pickle.WriteInt(histogram.declared_max());
pickle.WriteSize(histogram.bucket_count());
pickle.WriteInt(histogram.histogram_type());
pickle.WriteInt(histogram.flags());
snapshot.Serialize(&pickle);
return std::string(static_cast<const char*>(pickle.data()), pickle.size());
}
// static
bool Histogram::DeserializeHistogramInfo(const std::string& histogram_info) {
if (histogram_info.empty()) {
return false;
}
Pickle pickle(histogram_info.data(),
static_cast<int>(histogram_info.size()));
void* iter = NULL;
size_t bucket_count;
int declared_min;
int declared_max;
int histogram_type;
int pickle_flags;
std::string histogram_name;
SampleSet sample;
if (!pickle.ReadString(&iter, &histogram_name) ||
!pickle.ReadInt(&iter, &declared_min) ||
!pickle.ReadInt(&iter, &declared_max) ||
!pickle.ReadSize(&iter, &bucket_count) ||
!pickle.ReadInt(&iter, &histogram_type) ||
!pickle.ReadInt(&iter, &pickle_flags) ||
!sample.Histogram::SampleSet::Deserialize(&iter, pickle)) {
LOG(ERROR) << "Pickle error decoding Histogram: " << histogram_name;
return false;
}
DCHECK(pickle_flags & kIPCSerializationSourceFlag);
// Since these fields may have come from an untrusted renderer, do additional
// checks above and beyond those in Histogram::Initialize()
if (declared_max <= 0 || declared_min <= 0 || declared_max < declared_min ||
INT_MAX / sizeof(Count) <= bucket_count || bucket_count < 2) {
LOG(ERROR) << "Values error decoding Histogram: " << histogram_name;
return false;
}
Flags flags = static_cast<Flags>(pickle_flags & ~kIPCSerializationSourceFlag);
DCHECK(histogram_type != NOT_VALID_IN_RENDERER);
scoped_refptr<Histogram> render_histogram(NULL);
if (histogram_type == HISTOGRAM) {
render_histogram = Histogram::FactoryGet(
histogram_name, declared_min, declared_max, bucket_count, flags);
} else if (histogram_type == LINEAR_HISTOGRAM) {
render_histogram = LinearHistogram::FactoryGet(
histogram_name, declared_min, declared_max, bucket_count, flags);
} else if (histogram_type == BOOLEAN_HISTOGRAM) {
render_histogram = BooleanHistogram::FactoryGet(histogram_name, flags);
} else {
LOG(ERROR) << "Error Deserializing Histogram Unknown histogram_type: " <<
histogram_type;
return false;
}
DCHECK(declared_min == render_histogram->declared_min());
DCHECK(declared_max == render_histogram->declared_max());
DCHECK(bucket_count == render_histogram->bucket_count());
DCHECK(histogram_type == render_histogram->histogram_type());
if (render_histogram->flags() & kIPCSerializationSourceFlag) {
DLOG(INFO) << "Single process mode, histogram observed and not copied: " <<
histogram_name;
} else {
DCHECK(flags == (flags & render_histogram->flags()));
render_histogram->AddSampleSet(sample);
}
return true;
}
//------------------------------------------------------------------------------
// Methods for the Histogram::SampleSet class
//------------------------------------------------------------------------------
Histogram::SampleSet::SampleSet()
: counts_(),
sum_(0),
square_sum_(0) {
}
void Histogram::SampleSet::Resize(const Histogram& histogram) {
counts_.resize(histogram.bucket_count(), 0);
}
void Histogram::SampleSet::CheckSize(const Histogram& histogram) const {
DCHECK(counts_.size() == histogram.bucket_count());
}
void Histogram::SampleSet::Accumulate(Sample value, Count count,
size_t index) {
DCHECK(count == 1 || count == -1);
counts_[index] += count;
sum_ += count * value;
square_sum_ += (count * value) * static_cast<int64>(value);
DCHECK_GE(counts_[index], 0);
DCHECK_GE(sum_, 0);
DCHECK_GE(square_sum_, 0);
}
Count Histogram::SampleSet::TotalCount() const {
Count total = 0;
for (Counts::const_iterator it = counts_.begin();
it != counts_.end();
++it) {
total += *it;
}
return total;
}
void Histogram::SampleSet::Add(const SampleSet& other) {
DCHECK(counts_.size() == other.counts_.size());
sum_ += other.sum_;
square_sum_ += other.square_sum_;
for (size_t index = 0; index < counts_.size(); ++index)
counts_[index] += other.counts_[index];
}
void Histogram::SampleSet::Subtract(const SampleSet& other) {
DCHECK(counts_.size() == other.counts_.size());
// Note: Race conditions in snapshotting a sum or square_sum may lead to
// (temporary) negative values when snapshots are later combined (and deltas
// calculated). As a result, we don't currently CHCEK() for positive values.
sum_ -= other.sum_;
square_sum_ -= other.square_sum_;
for (size_t index = 0; index < counts_.size(); ++index) {
counts_[index] -= other.counts_[index];
DCHECK_GE(counts_[index], 0);
}
}
bool Histogram::SampleSet::Serialize(Pickle* pickle) const {
pickle->WriteInt64(sum_);
pickle->WriteInt64(square_sum_);
pickle->WriteSize(counts_.size());
for (size_t index = 0; index < counts_.size(); ++index) {
pickle->WriteInt(counts_[index]);
}
return true;
}
bool Histogram::SampleSet::Deserialize(void** iter, const Pickle& pickle) {
DCHECK_EQ(counts_.size(), 0u);
DCHECK_EQ(sum_, 0);
DCHECK_EQ(square_sum_, 0);
size_t counts_size;
if (!pickle.ReadInt64(iter, &sum_) ||
!pickle.ReadInt64(iter, &square_sum_) ||
!pickle.ReadSize(iter, &counts_size)) {
return false;
}
if (counts_size == 0)
return false;
for (size_t index = 0; index < counts_size; ++index) {
int i;
if (!pickle.ReadInt(iter, &i))
return false;
counts_.push_back(i);
}
return true;
}
//------------------------------------------------------------------------------
// LinearHistogram: This histogram uses a traditional set of evenly spaced
// buckets.
//------------------------------------------------------------------------------
scoped_refptr<Histogram> LinearHistogram::FactoryGet(
const std::string& name, Sample minimum, Sample maximum,
size_t bucket_count, Flags flags) {
scoped_refptr<Histogram> histogram(NULL);
if (minimum <= 0)
minimum = 1;
if (maximum >= kSampleType_MAX)
maximum = kSampleType_MAX - 1;
if (StatisticsRecorder::FindHistogram(name, &histogram)) {
DCHECK(histogram.get() != NULL);
} else {
histogram = new LinearHistogram(name, minimum, maximum, bucket_count);
scoped_refptr<Histogram> registered_histogram(NULL);
StatisticsRecorder::FindHistogram(name, ®istered_histogram);
if (registered_histogram.get() != NULL &&
registered_histogram.get() != histogram.get())
histogram = registered_histogram;
}
DCHECK(LINEAR_HISTOGRAM == histogram->histogram_type());
DCHECK(histogram->HasConstructorArguments(minimum, maximum, bucket_count));
histogram->SetFlags(flags);
return histogram;
}
scoped_refptr<Histogram> LinearHistogram::FactoryGet(const std::string& name,
base::TimeDelta minimum, base::TimeDelta maximum, size_t bucket_count,
Flags flags) {
return FactoryGet(name, minimum.InMilliseconds(), maximum.InMilliseconds(),
bucket_count, flags);
}
LinearHistogram::LinearHistogram(const std::string& name, Sample minimum,
Sample maximum, size_t bucket_count)
: Histogram(name, minimum >= 1 ? minimum : 1, maximum, bucket_count) {
InitializeBucketRange();
DCHECK(ValidateBucketRanges());
}
LinearHistogram::LinearHistogram(const std::string& name,
TimeDelta minimum, TimeDelta maximum, size_t bucket_count)
: Histogram(name, minimum >= TimeDelta::FromMilliseconds(1) ?
minimum : TimeDelta::FromMilliseconds(1),
maximum, bucket_count) {
// Do a "better" (different) job at init than a base classes did...
InitializeBucketRange();
DCHECK(ValidateBucketRanges());
}
void LinearHistogram::SetRangeDescriptions(
const DescriptionPair descriptions[]) {
for (int i =0; descriptions[i].description; ++i) {
bucket_description_[descriptions[i].sample] = descriptions[i].description;
}
}
const std::string LinearHistogram::GetAsciiBucketRange(size_t i) const {
int range = ranges(i);
BucketDescriptionMap::const_iterator it = bucket_description_.find(range);
if (it == bucket_description_.end())
return Histogram::GetAsciiBucketRange(i);
return it->second;
}
bool LinearHistogram::PrintEmptyBucket(size_t index) const {
return bucket_description_.find(ranges(index)) == bucket_description_.end();
}
void LinearHistogram::InitializeBucketRange() {
DCHECK_LT(0, declared_min()); // 0 is the underflow bucket here.
double min = declared_min();
double max = declared_max();
size_t i;
for (i = 1; i < bucket_count(); ++i) {
double linear_range = (min * (bucket_count() -1 - i) + max * (i - 1)) /
(bucket_count() - 2);
SetBucketRange(i, static_cast<int> (linear_range + 0.5));
}
}
double LinearHistogram::GetBucketSize(Count current, size_t i) const {
DCHECK(ranges(i + 1) > ranges(i));
// Adjacent buckets with different widths would have "surprisingly" many (few)
// samples in a histogram if we didn't normalize this way.
double denominator = ranges(i + 1) - ranges(i);
return current/denominator;
}
//------------------------------------------------------------------------------
// This section provides implementation for BooleanHistogram.
//------------------------------------------------------------------------------
scoped_refptr<Histogram> BooleanHistogram::FactoryGet(const std::string& name,
Flags flags) {
scoped_refptr<Histogram> histogram(NULL);
if (StatisticsRecorder::FindHistogram(name, &histogram)) {
DCHECK(histogram.get() != NULL);
} else {
histogram = new BooleanHistogram(name);
scoped_refptr<Histogram> registered_histogram(NULL);
StatisticsRecorder::FindHistogram(name, ®istered_histogram);
if (registered_histogram.get() != NULL &&
registered_histogram.get() != histogram.get())
histogram = registered_histogram;
}
DCHECK(BOOLEAN_HISTOGRAM == histogram->histogram_type());
histogram->SetFlags(flags);
return histogram;
}
//------------------------------------------------------------------------------
// The next section handles global (central) support for all histograms, as well
// as startup/teardown of this service.
//------------------------------------------------------------------------------
// This singleton instance should be started during the single threaded portion
// of main(), and hence it is not thread safe. It initializes globals to
// provide support for all future calls.
StatisticsRecorder::StatisticsRecorder() {
DCHECK(!histograms_);
lock_ = new Lock;
histograms_ = new HistogramMap;
}
StatisticsRecorder::~StatisticsRecorder() {
DCHECK(histograms_);
if (dump_on_exit_) {
std::string output;
WriteGraph("", &output);
LOG(INFO) << output;
}
// Clean up.
delete histograms_;
histograms_ = NULL;
delete lock_;
lock_ = NULL;
}
// static
bool StatisticsRecorder::WasStarted() {
return NULL != histograms_;
}
// Note: We can't accept a ref_ptr to |histogram| because we *might* not keep a
// reference, and we are called while in the Histogram constructor. In that
// scenario, a ref_ptr would have incremented the ref count when the histogram
// was passed to us, decremented it when we returned, and the instance would be
// destroyed before assignment (when value was returned by new).
// static
void StatisticsRecorder::Register(Histogram* histogram) {
if (!histograms_)
return;
const std::string name = histogram->histogram_name();
AutoLock auto_lock(*lock_);
DCHECK(histograms_->end() == histograms_->find(name));
(*histograms_)[name] = histogram;
return;
}
// static
void StatisticsRecorder::WriteHTMLGraph(const std::string& query,
std::string* output) {
if (!histograms_)
return;
output->append("<html><head><title>About Histograms");
if (!query.empty())
output->append(" - " + query);
output->append("</title>"
// We'd like the following no-cache... but it doesn't work.
// "<META HTTP-EQUIV=\"Pragma\" CONTENT=\"no-cache\">"
"</head><body>");
Histograms snapshot;
GetSnapshot(query, &snapshot);
for (Histograms::iterator it = snapshot.begin();
it != snapshot.end();
++it) {
(*it)->WriteHTMLGraph(output);
output->append("<br><hr><br>");
}
output->append("</body></html>");
}
// static
void StatisticsRecorder::WriteGraph(const std::string& query,
std::string* output) {
if (!histograms_)
return;
if (query.length())
StringAppendF(output, "Collections of histograms for %s\n", query.c_str());
else
output->append("Collections of all histograms\n");
Histograms snapshot;
GetSnapshot(query, &snapshot);
for (Histograms::iterator it = snapshot.begin();
it != snapshot.end();
++it) {
(*it)->WriteAscii(true, "\n", output);
output->append("\n");
}
}
// static
void StatisticsRecorder::GetHistograms(Histograms* output) {
if (!histograms_)
return;
AutoLock auto_lock(*lock_);
for (HistogramMap::iterator it = histograms_->begin();
histograms_->end() != it;
++it) {
output->push_back(it->second);
}
}
bool StatisticsRecorder::FindHistogram(const std::string& name,
scoped_refptr<Histogram>* histogram) {
if (!histograms_)
return false;
AutoLock auto_lock(*lock_);
HistogramMap::iterator it = histograms_->find(name);
if (histograms_->end() == it)
return false;
*histogram = it->second;
return true;
}
// private static
void StatisticsRecorder::GetSnapshot(const std::string& query,
Histograms* snapshot) {
AutoLock auto_lock(*lock_);
for (HistogramMap::iterator it = histograms_->begin();
histograms_->end() != it;
++it) {
if (it->first.find(query) != std::string::npos)
snapshot->push_back(it->second);
}
}
// static
StatisticsRecorder::HistogramMap* StatisticsRecorder::histograms_ = NULL;
// static
Lock* StatisticsRecorder::lock_ = NULL;
// static
bool StatisticsRecorder::dump_on_exit_ = false;