Preparation CL for adding crash metrics UMA counters to ChromeFrame. Basicall...

chrome/common/metrics_helpers.h

+// Copyright (c) 2010 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.
+
+// This file defines a set of user experience metrics data recorded by
+// the MetricsService.  This is the unit of data that is sent to the server.
+
+#ifndef CHROME_COMMON_METRICS_HELPERS_H_
+#define CHROME_COMMON_METRICS_HELPERS_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/histogram.h"
+#include "base/time.h"
+#include "chrome/common/page_transition_types.h"
+
+#include "libxml/xmlwriter.h"
+
+class GURL;
+class MetricsLog;
+
+// This class provides base functionality for logging metrics data.
+class MetricsLogBase {
+ public:
+  // Creates a new metrics log
+  // client_id is the identifier for this profile on this installation
+  // session_id is an integer that's incremented on each application launch
+  MetricsLogBase(const std::string& client_id, int session_id,
+                 const std::string& version_string);
+  virtual ~MetricsLogBase();
+
+  // Records a user-initiated action.
+  void RecordUserAction(const char* key);
+
+  enum WindowEventType {
+    WINDOW_CREATE = 0,
+    WINDOW_OPEN,
+    WINDOW_CLOSE,
+    WINDOW_DESTROY
+  };
+
+  void RecordWindowEvent(WindowEventType type, int window_id, int parent_id);
+
+  // Records a page load.
+  // window_id - the index of the tab in which the load took place
+  // url - which URL was loaded
+  // origin - what kind of action initiated the load
+  // load_time - how long it took to load the page
+  void RecordLoadEvent(int window_id,
+                       const GURL& url,
+                       PageTransition::Type origin,
+                       int session_index,
+                       base::TimeDelta load_time);
+
+  // Record any changes in a given histogram for transmission.
+  void RecordHistogramDelta(const Histogram& histogram,
+                            const Histogram::SampleSet& snapshot);
+
+  // Stop writing to this record and generate the encoded representation.
+  // None of the Record* methods can be called after this is called.
+  void CloseLog();
+
+  // These methods allow retrieval of the encoded representation of the
+  // record.  They can only be called after CloseLog() has been called.
+  // GetEncodedLog returns false if buffer_size is less than
+  // GetEncodedLogSize();
+  int GetEncodedLogSize();
+  bool GetEncodedLog(char* buffer, int buffer_size);
+  // Returns an empty string on failure.
+  std::string GetEncodedLogString();
+
+  // Returns the amount of time in seconds that this log has been in use.
+  int GetElapsedSeconds();
+
+  int num_events() { return num_events_; }
+
+  // Creates an MD5 hash of the given value, and returns hash as a byte
+  // buffer encoded as a std::string.
+  static std::string CreateHash(const std::string& value);
+
+  // Return a base64-encoded MD5 hash of the given string.
+  static std::string CreateBase64Hash(const std::string& string);
+
+  // Get the GMT buildtime for the current binary, expressed in seconds since
+  // Januray 1, 1970 GMT.
+  // The value is used to identify when a new build is run, so that previous
+  // reliability stats, from other builds, can be abandoned.
+  static int64 GetBuildTime();
+
+  // Use |extension| in all uploaded appversions in addition to the standard
+  // version string.
+  static void set_version_extension(const std::string& extension) {
+    version_extension_ = extension;
+  }
+
+  virtual MetricsLog* AsMetricsLog() {
+    return NULL;
+  }
+
+ protected:
+  // Returns a string containing the current time.
+  // Virtual so that it can be overridden for testing.
+  virtual std::string GetCurrentTimeString();
+  // Helper class that invokes StartElement from constructor, and EndElement
+  // from destructor.
+  //
+  // Use the macro OPEN_ELEMENT_FOR_SCOPE to help avoid usage problems.
+  class ScopedElement {
+   public:
+    ScopedElement(MetricsLogBase* log, const std::string& name) : log_(log) {
+      DCHECK(log);
+      log->StartElement(name.c_str());
+    }
+
+    ScopedElement(MetricsLogBase* log, const char* name) : log_(log) {
+      DCHECK(log);
+      log->StartElement(name);
+    }
+
+    ~ScopedElement() {
+      log_->EndElement();
+    }
+
+   private:
+     MetricsLogBase* log_;
+  };
+  friend class ScopedElement;
+
+  static const char* WindowEventTypeToString(WindowEventType type);
+
+  // Convenience versions of xmlWriter functions
+  void StartElement(const char* name);
+  void EndElement();
+  void WriteAttribute(const std::string& name, const std::string& value);
+  void WriteIntAttribute(const std::string& name, int value);
+  void WriteInt64Attribute(const std::string& name, int64 value);
+
+  // Write the attributes that are common to every metrics event type.
+  void WriteCommonEventAttributes();
+
+  // An extension that is appended to the appversion in each log.
+  static std::string version_extension_;
+
+  base::Time start_time_;
+  base::Time end_time_;
+
+  std::string client_id_;
+  std::string session_id_;
+
+  // locked_ is true when record has been packed up for sending, and should
+  // no longer be written to.  It is only used for sanity checking and is
+  // not a real lock.
+  bool locked_;
+
+  xmlBufferPtr buffer_;
+  xmlTextWriterPtr writer_;
+  int num_events_;  // the number of events recorded in this log
+
+  DISALLOW_COPY_AND_ASSIGN(MetricsLogBase);
+};
+
+// This class provides base functionality for logging metrics data.
+// TODO(ananta)
+// Factor out more common code from chrome and chrome frame metrics service
+// into this class.
+class MetricsServiceBase {
+ protected:
+  MetricsServiceBase();
+  virtual ~MetricsServiceBase();
+
+  // Check to see if there is a log that needs to be, or is being, transmitted.
+  bool pending_log() const {
+    return pending_log_ || !pending_log_text_.empty();
+  }
+
+  // Compress the report log in input using bzip2, store the result in output.
+  bool Bzip2Compress(const std::string& input, std::string* output);
+
+  // Discard pending_log_, and clear pending_log_text_. Called after processing
+  // of this log is complete.
+  void DiscardPendingLog();
+
+  // Record complete list of histograms into the current log.
+  // Called when we close a log.
+  void RecordCurrentHistograms();
+
+  // Record a specific histogram .
+  void RecordHistogram(const Histogram& histogram);
+
+  // A log that we are currently transmiting, or about to try to transmit.
+  MetricsLogBase* pending_log_;
+
+  // An alternate form of pending_log_.  We persistently save this text version
+  // into prefs if we can't transmit it.  As a result, sometimes all we have is
+  // the text version (recalled from a previous session).
+  std::string pending_log_text_;
+
+  // The log that we are still appending to.
+  MetricsLogBase* current_log_;
+
+  // Maintain a map of histogram names to the sample stats we've sent.
+  typedef std::map<std::string, Histogram::SampleSet> LoggedSampleMap;
+
+  // For histograms, record what we've already logged (as a sample for each
+  // histogram) so that we can send only the delta with the next log.
+  LoggedSampleMap logged_samples_;
+};
+
+#endif  // CHROME_COMMON_METRICS_HELPERS_H_
+