| /* |
| * Copyright 2011 Google Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| // Author: jmarantz@google.com (Joshua Marantz) |
| |
| #ifndef PAGESPEED_KERNEL_BASE_WAVEFORM_H_ |
| #define PAGESPEED_KERNEL_BASE_WAVEFORM_H_ |
| |
| #include <utility> // for pair |
| |
| #include "pagespeed/kernel/base/basictypes.h" |
| #include "pagespeed/kernel/base/scoped_ptr.h" |
| #include "pagespeed/kernel/base/string_util.h" |
| |
| namespace net_instaweb { |
| |
| class AbstractMutex; |
| class MessageHandler; |
| class ThreadSystem; |
| class Timer; |
| class UpDownCounter; |
| class Writer; |
| |
| // Displays a waveform of values over time. This can run |
| // continuously, in which case it will only display waveforms for a |
| // bounded number of samples. Or it can be run as a trigger. |
| // |
| // However the average, min, and max values will account for all the |
| // values seen by the waveform since it was cleared. |
| // |
| // This class is threadsafe. |
| class Waveform { |
| public: |
| Waveform(ThreadSystem* thread_system, Timer* timer, int capacity, |
| UpDownCounter* metric); |
| |
| void Clear(); |
| double Average(); |
| double Maximum(); |
| double Minimum(); |
| int Size(); |
| |
| // Records a value at the current time using the Timer. |
| void Add(double value); |
| |
| // Records a delta relative to the previous value using the Timer. |
| // This is equivalent to calling Add(previous_value + delta). |
| void AddDelta(double delta); |
| |
| // Write script and function to web page. Note that this function |
| // should be called only once for each HTML page, and should not be |
| // used for each waveform. |
| static void RenderHeader(Writer* writer, MessageHandler* handler); |
| |
| // Renders a waveform into HTML. |
| void Render(const StringPiece& title, const StringPiece& label, |
| Writer* writer, MessageHandler* handler); |
| |
| private: |
| typedef std::pair<int64, double> TimeValue; |
| |
| TimeValue* GetSample(int index); // Must be called with mutex held. |
| void AddHelper(double value); // Must be called with mutex held. |
| |
| Timer* timer_; |
| int capacity_; |
| scoped_array<TimeValue> samples_; |
| int start_index_; |
| int size_; |
| int64 first_sample_timestamp_us_; |
| double total_since_clear_; |
| double min_; |
| double max_; |
| double previous_value_; |
| scoped_ptr<AbstractMutex> mutex_; // protects all the above member variables. |
| |
| // Un-owned pointer to a variable to export current waveform values. |
| // May be NULL. |
| UpDownCounter* metric_; |
| |
| DISALLOW_COPY_AND_ASSIGN(Waveform); |
| }; |
| |
| } // namespace net_instaweb |
| |
| #endif // PAGESPEED_KERNEL_BASE_WAVEFORM_H_ |