// Copyright (c) 2010 The Chromium OS 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 METRICS_LIBRARY_H_ #define METRICS_LIBRARY_H_ #include #include #include // for FRIEND_TEST class MetricsLibraryInterface { public: virtual void Init() = 0; virtual bool SendToUMA(const std::string& name, int sample, int min, int max, int nbuckets) = 0; virtual bool SendEnumToUMA(const std::string& name, int sample, int max) = 0; virtual ~MetricsLibraryInterface() {} }; // Library used to send metrics to both Autotest and Chrome/UMA. class MetricsLibrary : public MetricsLibraryInterface { public: MetricsLibrary(); // Initializes the library. void Init(); // Returns whether or not metrics collection is enabled. bool AreMetricsEnabled(); // Sends histogram data to Chrome for transport to UMA and returns // true on success. This method results in the equivalent of an // asynchronous non-blocking RPC to UMA_HISTOGRAM_CUSTOM_COUNTS // inside Chrome (see base/histogram.h). // // |sample| is the sample value to be recorded (|min| <= |sample| < |max|). // |min| is the minimum value of the histogram samples (|min| > 0). // |max| is the maximum value of the histogram samples. // |nbuckets| is the number of histogram buckets. // [0,min) is the implicit underflow bucket. // [|max|,infinity) is the implicit overflow bucket. // // Note that the memory allocated in Chrome for each histogram is // proportional to the number of buckets. Therefore, it is strongly // recommended to keep this number low (e.g., 50 is normal, while // 100 is high). bool SendToUMA(const std::string& name, int sample, int min, int max, int nbuckets); // Sends linear histogram data to Chrome for transport to UMA and // returns true on success. This method results in the equivalent of // an asynchronous non-blocking RPC to UMA_HISTOGRAM_ENUMERATION // inside Chrome (see base/histogram.h). // // |sample| is the sample value to be recorded (1 <= |sample| < |max|). // |max| is the maximum value of the histogram samples. // 0 is the implicit underflow bucket. // [|max|,infinity) is the implicit overflow bucket. // // An enumaration histogram requires |max| + 1 number of // buckets. Note that the memory allocated in Chrome for each // histogram is proportional to the number of buckets. Therefore, it // is strongly recommended to keep this number low (e.g., 50 is // normal, while 100 is high). bool SendEnumToUMA(const std::string& name, int sample, int max); // Sends to Autotest and returns true on success. static bool SendToAutotest(const std::string& name, int value); private: friend class CMetricsLibraryTest; friend class MetricsLibraryTest; FRIEND_TEST(MetricsLibraryTest, AreMetricsEnabled); FRIEND_TEST(MetricsLibraryTest, FormatChromeMessage); FRIEND_TEST(MetricsLibraryTest, FormatChromeMessageTooLong); FRIEND_TEST(MetricsLibraryTest, SendMessageToChrome); FRIEND_TEST(MetricsLibraryTest, SendMessageToChromeUMAEventsBadFileLocation); // Sends message of size |length| to Chrome for transport to UMA and // returns true on success. bool SendMessageToChrome(int32_t length, const char* message); // Formats a name/value message for Chrome in |buffer| and returns the // length of the message or a negative value on error. // // Message format is: | LENGTH(binary) | NAME | \0 | VALUE | \0 | // // The arbitrary |format| argument covers the non-LENGTH portion of the // message. The caller is responsible to store the \0 character // between NAME and VALUE (e.g. "%s%c%d", name, '\0', value). int32_t FormatChromeMessage(int32_t buffer_size, char* buffer, const char* format, ...); // Time at which we last checked if metrics were enabled. static time_t cached_enabled_time_; // Cached state of whether or not metrics were enabled. static bool cached_enabled_; const char* uma_events_file_; const char* consent_file_; }; #endif // METRICS_LIBRARY_H_