// Copyright (c) 2012 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.

#ifndef CHROME_BROWSER_MEMORY_DETAILS_H_
#define CHROME_BROWSER_MEMORY_DETAILS_H_

#include <map>
#include <vector>

#include "base/memory/ref_counted.h"
#include "base/process/process_handle.h"
#include "base/process/process_metrics.h"
#include "base/strings/string16.h"
#include "base/time/time.h"
#include "chrome/browser/site_details.h"
#include "content/public/common/process_type.h"

// We collect data about each browser process.  A browser may
// have multiple processes (of course!).  Even IE has multiple
// processes these days.
struct ProcessMemoryInformation {
  // NOTE: Do not remove or reorder the elements in this enum, and only add new
  // items at the end. We depend on these specific values in a histogram.
  enum RendererProcessType {
    RENDERER_UNKNOWN = 0,
    RENDERER_NORMAL,
    RENDERER_CHROME,        // WebUI (chrome:// URL)
    RENDERER_EXTENSION,     // chrome-extension://
    RENDERER_DEVTOOLS,      // Web inspector
    RENDERER_INTERSTITIAL,  // malware/phishing interstitial
    RENDERER_BACKGROUND_APP // hosted app background page
  };

  static std::string GetRendererTypeNameInEnglish(RendererProcessType type);
  static std::string GetFullTypeNameInEnglish(
      int process_type,
      RendererProcessType rtype);

  ProcessMemoryInformation();
  ~ProcessMemoryInformation();

  // Default ordering is by private memory consumption.
  bool operator<(const ProcessMemoryInformation& rhs) const;

  // The process id.
  base::ProcessId pid;
  // The working set information.
  base::WorkingSetKBytes working_set;
  // The committed bytes.
  base::CommittedKBytes committed;
  // The process version
  base::string16 version;
  // The process product name.
  base::string16 product_name;
  // The number of processes which this memory represents.
  int num_processes;
  // A process is a diagnostics process if it is rendering about:memory.
  // Mark this specially so that it can avoid counting it in its own
  // results.
  bool is_diagnostics;
  // If this is a child process of Chrome, what type (i.e. plugin) it is.
  int process_type;
  // If this is a renderer process, what type it is.
  RendererProcessType renderer_type;
  // A collection of titles used, i.e. for a tab it'll show all the page titles.
  std::vector<base::string16> titles;
};

typedef std::vector<ProcessMemoryInformation> ProcessMemoryInformationList;

// Browser Process Information.
struct ProcessData {
  ProcessData();
  ProcessData(const ProcessData& rhs);
  ~ProcessData();
  ProcessData& operator=(const ProcessData& rhs);

  base::string16 name;
  base::string16 process_name;
  ProcessMemoryInformationList processes;

  // Track site data for predicting process counts with out-of-process iframes.
  // See site_details.h.
  BrowserContextSiteDataMap site_data;
};

// MemoryGrowthTracker tracks latest metrics about record time and memory usage
// at that time per process.
class MemoryGrowthTracker {
 public:
  MemoryGrowthTracker();
  ~MemoryGrowthTracker();

  // If 30 minutes have passed since last UMA record, UpdateSample() computes
  // a difference between current memory usage |sample| of process |pid| and
  // stored memory usage at the time of last UMA record. Then, it updates the
  // stored memory usage to |sample|, stores the difference in |diff| and
  // returns true.
  // If no memory usage of |pid| has not been recorded so far or 30 minutes
  // have not passed since last record, it just returns false.
  // |sample| is memory usage in kB.
  bool UpdateSample(base::ProcessId pid, int sample, int* diff);

 private:
  // Latest metrics about record time and memory usage at that time per process.
  // The second values of |memory_sizes_| are in kB.
  std::map<base::ProcessId, base::TimeTicks> times_;
  std::map<base::ProcessId, int> memory_sizes_;

  DISALLOW_COPY_AND_ASSIGN(MemoryGrowthTracker);
};

#if defined(OS_MACOSX)
class ProcessInfoSnapshot;
#endif

// MemoryDetails fetches memory details about current running browsers.
// Because this data can only be fetched asynchronously, callers use
// this class via a callback.
//
// Example usage:
//
//    class MyMemoryDetailConsumer : public MemoryDetails {
//
//      MyMemoryDetailConsumer() {
//        // Anything but |StartFetch()|.
//      }
//
//      // (Or just call |StartFetch()| explicitly if there's nothing else to
//      // do.)
//      void StartDoingStuff() {
//        StartFetch();  // Starts fetching details.
//        // Etc.
//      }
//
//      // Your other class stuff here
//
//      virtual void OnDetailsAvailable() {
//        // do work with memory info here
//      }
//    }
class MemoryDetails : public base::RefCountedThreadSafe<MemoryDetails> {
 public:
  enum UserMetricsMode {
    UPDATE_USER_METRICS,  // Update UMA memory histograms with results.
    SKIP_USER_METRICS
  };

  // Constructor.
  MemoryDetails();

  // Access to the process detail information.  This data is only available
  // after OnDetailsAvailable() has been called.
  const std::vector<ProcessData>& processes() { return process_data_; }

  // Initiate updating the current memory details.  These are fetched
  // asynchronously because data must be collected from multiple threads.
  // Updates UMA memory histograms if |mode| is UPDATE_USER_METRICS.
  // OnDetailsAvailable will be called when this process is complete.
  void StartFetch(UserMetricsMode user_metrics_mode);

  virtual void OnDetailsAvailable() = 0;

  // Returns a string summarizing memory usage of the Chrome browser process
  // and all sub-processes, suitable for logging.
  std::string ToLogString();

 protected:
  friend class base::RefCountedThreadSafe<MemoryDetails>;

  virtual ~MemoryDetails();

  // Set MemoryGrowthTracker into MemoryDetails.
  void SetMemoryGrowthTracker(MemoryGrowthTracker* memory_growth_tracker);

 private:
  // Collect child process information on the IO thread.  This is needed because
  // information about some child process types (i.e. plugins) can only be taken
  // on that thread.  The data will be used by about:memory.  When finished,
  // invokes back to the file thread to run the rest of the about:memory
  // functionality.
  void CollectChildInfoOnIOThread();

  // Collect current process information from the OS and store it
  // for processing.  If data has already been collected, clears old
  // data and re-collects the data.
  // Note - this function enumerates memory details from many processes
  // and is fairly expensive to run, hence it's run on the file thread.
  // The parameter holds information about processes from the IO thread.
  void CollectProcessData(const std::vector<ProcessMemoryInformation>&);

#if defined(OS_MACOSX)
  // A helper for |CollectProcessData()|, collecting data on the Chrome/Chromium
  // process with PID |pid|. The collected data is added to the state of the
  // object (in |process_data_|).
  void CollectProcessDataChrome(
      const std::vector<ProcessMemoryInformation>& child_info,
      base::ProcessId pid,
      const ProcessInfoSnapshot& process_info);
#endif

  // Collect child process information on the UI thread.  Information about
  // renderer processes is only available there.
  void CollectChildInfoOnUIThread();

  // Updates the global histograms for tracking memory usage.
  void UpdateHistograms();

#if defined(OS_CHROMEOS)
  void UpdateSwapHistograms();
#endif

  // Returns a pointer to the ProcessData structure for Chrome.
  ProcessData* ChromeBrowser();

  std::vector<ProcessData> process_data_;

  UserMetricsMode user_metrics_mode_;

  // A pointer to MemoryGrowthTracker which is contained in a longer-lived
  // owner of MemoryDetails, for example, ChromeMetricsServiceClient.
  // The pointer is NULL by default and set by SetMemoryGrowthTracker().
  // If it is NULL, nothing is tracked.
  MemoryGrowthTracker* memory_growth_tracker_;

#if defined(OS_CHROMEOS)
  base::SwapInfo swap_info_;
#endif

  DISALLOW_COPY_AND_ASSIGN(MemoryDetails);
};

#endif  // CHROME_BROWSER_MEMORY_DETAILS_H_