chromium/src/third_party/blink/renderer/platform/fonts/font_matching_metrics.h - manifest_repos/chromium_src - Git at Google

 // Copyright 2019 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 THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_MATCHING_METRICS_H_
 #define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_MATCHING_METRICS_H_

 #include "services/metrics/public/cpp/ukm_source_id.h"
 #include "third_party/blink/public/common/privacy_budget/identifiable_token.h"
 #include "third_party/blink/public/common/privacy_budget/identifiable_token_builder.h"
 #include "third_party/blink/renderer/platform/fonts/font_description.h"
 #include "third_party/blink/renderer/platform/fonts/font_fallback_priority.h"
 #include "third_party/blink/renderer/platform/fonts/simple_font_data.h"
 #include "third_party/blink/renderer/platform/platform_export.h"
 #include "third_party/blink/renderer/platform/timer.h"
 #include "third_party/blink/renderer/platform/wtf/hash_functions.h"
 #include "third_party/blink/renderer/platform/wtf/hash_set.h"
 #include "third_party/blink/renderer/platform/wtf/text/atomic_string.h"

 namespace ukm {
 class UkmRecorder;
 }  // namespace ukm

 namespace blink {

 // A (generic) wrapper around IdentifiableToken to enable its use as a HashMap
 // key. The |token| represents the parameters by which a font was looked up.
 // However, if |is_deleted_value| or |is_empty_value|, this key represents an
 // object for HashMap's internal use only. In that case, |token| is left as a
 // default value.
 struct IdentifiableTokenKey {
   IdentifiableToken token;
   bool is_deleted_value = false;
   bool is_empty_value = false;

   IdentifiableTokenKey() : is_empty_value(true) {}
   explicit IdentifiableTokenKey(const IdentifiableToken& token)
       : token(token) {}
   explicit IdentifiableTokenKey(WTF::HashTableDeletedValueType)
       : is_deleted_value(true) {}

   bool IsHashTableDeletedValue() const { return is_deleted_value; }

   bool operator==(const IdentifiableTokenKey& other) const {
     return token == other.token && is_deleted_value == other.is_deleted_value &&
            is_empty_value == other.is_empty_value;
   }
   bool operator!=(const IdentifiableTokenKey& other) const {
     return !(*this == other);
   }
 };

 // A helper that defines the hash and equality functions that HashMap should use
 // internally for comparing IdentifiableTokenKeys.
 struct IdentifiableTokenKeyHash {
   STATIC_ONLY(IdentifiableTokenKeyHash);
   static unsigned GetHash(const IdentifiableTokenKey& key) {
     IntHash<int64_t> hasher;
     return hasher.GetHash(key.token.ToUkmMetricValue()) ^
            hasher.GetHash((key.is_deleted_value << 1) + key.is_empty_value);
   }
   static bool Equal(const IdentifiableTokenKey& a,
                     const IdentifiableTokenKey& b) {
     return a == b;
   }
   static const bool safe_to_compare_to_empty_or_deleted = true;
 };

 // A helper that defines the invalid 'empty value' that HashMap should use
 // internally.
 struct IdentifiableTokenKeyHashTraits
     : WTF::SimpleClassHashTraits<IdentifiableTokenKey> {
   STATIC_ONLY(IdentifiableTokenKeyHashTraits);
   static const bool kEmptyValueIsZero = false;
   static IdentifiableTokenKey EmptyValue() { return IdentifiableTokenKey(); }
 };

 // Tracks and reports UKM metrics of attempted font family match attempts (both
 // successful and not successful) by the current frame.
 //
 // The number of successful / not successful font family match attempts are
 // reported to UKM. The class de-dupes attempts to match the same font family
 // name such that they are counted as one attempt.
 //
 // Each local font lookup is also reported as is each mapping of generic font
 // family name to its corresponding actual font family names. Local font lookups
 // are deduped according to the family name looked up in the FontCache and the
 // FontSelectionRequest parameters (i.e. weight, width and slope). Generic font
 // family lookups are de-duped according to the generic name, the
 // GenericFamilyType and the script. Both types of lookup events are reported
 // regularly.
 class PLATFORM_EXPORT FontMatchingMetrics {
  public:
   enum FontLoadContext { kTopLevelFrame = 0, kSubframe, kWorker };

   // Create a FontMatchingMetrics objects for a frame, with |top_level|
   // indicating whether it is a mainframe.
   FontMatchingMetrics(bool top_level,
                       ukm::UkmRecorder* ukm_recorder,
                       ukm::SourceId source_id,
                       scoped_refptr<base::SingleThreadTaskRunner> task_runner);

   // Create a FontMatchingMetrics objects for a worker.
   FontMatchingMetrics(ukm::UkmRecorder* ukm_recorder,
                       ukm::SourceId source_id,
                       scoped_refptr<base::SingleThreadTaskRunner> task_runner);

   // Called when a page attempts to match a font family, and the font family is
   // available.
   void ReportSuccessfulFontFamilyMatch(const AtomicString& font_family_name);

   // Called when a page attempts to match a font family, and the font family is
   // not available.
   void ReportFailedFontFamilyMatch(const AtomicString& font_family_name);

   // Called when a page attempts to match a system font family.
   void ReportSystemFontFamily(const AtomicString& font_family_name);

   // Called when a page attempts to match a web font family.
   void ReportWebFontFamily(const AtomicString& font_family_name);

   // Reports a font listed in a @font-face src:local rule that successfully
   // matched.
   void ReportSuccessfulLocalFontMatch(const AtomicString& font_name);

   // Reports a font listed in a @font-face src:local rule that didn't
   // successfully match.
   void ReportFailedLocalFontMatch(const AtomicString& font_name);

   // Reports a local font was looked up by a name and font description. This
   // only includes lookups where the name is allowed to match family names,
   // PostScript names and full font names.
   void ReportFontLookupByUniqueOrFamilyName(
       const AtomicString& name,
       const FontDescription& font_description,
       SimpleFontData* resulting_font_data);

   // Reports a local font was looked up by a name and font description. This
   // only includes lookups where the name is allowed to match PostScript names
   // and full font names, but not family names.
   void ReportFontLookupByUniqueNameOnly(const AtomicString& name,
                                         const FontDescription& font_description,
                                         SimpleFontData* resulting_font_data,
                                         bool is_loading_fallback = false);

   // Reports a font was looked up by a fallback character, fallback priority,
   // and a font description.
   void ReportFontLookupByFallbackCharacter(
       UChar32 fallback_character,
       FontFallbackPriority fallback_priority,
       const FontDescription& font_description,
       SimpleFontData* resulting_font_data);

   // Reports a last-resort fallback font was looked up by a font description.
   void ReportLastResortFallbackFontLookup(
       const FontDescription& font_description,
       SimpleFontData* resulting_font_data);

   // Reports a generic font family name was matched according to the script and
   // the user's preferences to a font family name.
   void ReportFontFamilyLookupByGenericFamily(
       const AtomicString& generic_font_family_name,
       UScriptCode script,
       FontDescription::GenericFamilyType generic_family_type,
       const AtomicString& resulting_font_name);

   // Called on page unload and forces metrics to be flushed.
   void PublishAllMetrics();

   // Called whenever a font lookup event that will be saved in |font_tracker| or
   // |user_font_preference_mapping| occurs.
   void OnFontLookup();

   // Publishes the font lookup events. Recorded on document shutdown/worker
   // destruction and every minute, as long as additional lookups are occurring.
   void PublishIdentifiabilityMetrics();

   // Publishes the number of font family matches attempted (both successful
   // and otherwise) to UKM. Recorded on page unload.
   void PublishUkmMetrics();

  private:
   void IdentifiabilityMetricsTimerFired(TimerBase*);

   // This HashMap generically stores details of font lookups, i.e. what was used
   // to search for the font, and what the resulting font was. The key is an
   // IdentifiableTokenKey representing a wrapper around a digest of the lookup
   // parameters. The value is an IdentifiableToken representing either a digest
   // of the returned typeface or 0, if no valid typeface was found.
   using TokenToTokenHashMap = HashMap<IdentifiableTokenKey,
                                       IdentifiableToken,
                                       IdentifiableTokenKeyHash,
                                       IdentifiableTokenKeyHashTraits>;

   // Adds a digest of the |font_data|'s typeface to |hash_map| using the key
   // |input_key|, unless that key is already present. If |font_data| is not
   // nullptr, then the typeface digest will also be saved with its PostScript
   // name in |font_load_postscript_name_|.
   void InsertFontHashIntoMap(IdentifiableTokenKey input_key,
                              SimpleFontData* font_data,
                              TokenToTokenHashMap& hash_map);

   // Reports a local font's existence was looked up by a name, but its actual
   // font data may or may not have been loaded. This only includes lookups where
   // the name is allowed to match PostScript names and full font names, but not
   // family names.
   void ReportLocalFontExistenceByUniqueNameOnly(const AtomicString& font_name,
                                                 bool font_exists);

   // Constructs a builder with a hash of the FontSelectionRequest already added.
   IdentifiableTokenBuilder GetTokenBuilderWithFontSelectionRequest(
       const FontDescription& font_description);

   // Get a hash that uniquely represents the font data. Returns 0 if |font_data|
   // is nullptr.
   int64_t GetHashForFontData(SimpleFontData* font_data);

   void Initialize();

   // Get a token that uniquely represents the typeface's PostScript name. May
   // represent the empty string if no PostScript name was found.
   IdentifiableToken GetPostScriptNameTokenForFontData(
       SimpleFontData* font_data);

   // Font family names successfully matched.
   HashSet<AtomicString> successful_font_families_;

   // Font family names that weren't successfully matched.
   HashSet<AtomicString> failed_font_families_;

   // System font families the page attempted to match.
   HashSet<AtomicString> system_font_families_;

   // Web font families the page attempted to match.
   HashSet<AtomicString> web_font_families_;

   // @font-face src:local fonts that successfully matched.
   HashSet<AtomicString> local_fonts_succeeded_;

   // @font-face src:local fonts that didn't successfully match.
   HashSet<AtomicString> local_fonts_failed_;

   // Indicates whether this FontMatchingMetrics instance is for a top-level
   // frame, a subframe or a worker.
   const FontLoadContext load_context_;

   TokenToTokenHashMap font_lookups_by_unique_or_family_name_;
   TokenToTokenHashMap font_lookups_by_unique_name_only_;
   TokenToTokenHashMap font_lookups_by_fallback_character_;
   TokenToTokenHashMap font_lookups_as_last_resort_;
   TokenToTokenHashMap generic_font_lookups_;
   TokenToTokenHashMap font_load_postscript_name_;
   TokenToTokenHashMap local_font_existence_by_unique_name_only_;

   ukm::UkmRecorder* const ukm_recorder_;
   const ukm::SourceId source_id_;

   TaskRunnerTimer<FontMatchingMetrics> identifiability_metrics_timer_;
 };

 }  // namespace blink

 #endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_MATCHING_METRICS_H_
	// Copyright 2019 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 THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_MATCHING_METRICS_H_
	#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_MATCHING_METRICS_H_

	#include "services/metrics/public/cpp/ukm_source_id.h"
	#include "third_party/blink/public/common/privacy_budget/identifiable_token.h"
	#include "third_party/blink/public/common/privacy_budget/identifiable_token_builder.h"
	#include "third_party/blink/renderer/platform/fonts/font_description.h"
	#include "third_party/blink/renderer/platform/fonts/font_fallback_priority.h"
	#include "third_party/blink/renderer/platform/fonts/simple_font_data.h"
	#include "third_party/blink/renderer/platform/platform_export.h"
	#include "third_party/blink/renderer/platform/timer.h"
	#include "third_party/blink/renderer/platform/wtf/hash_functions.h"
	#include "third_party/blink/renderer/platform/wtf/hash_set.h"
	#include "third_party/blink/renderer/platform/wtf/text/atomic_string.h"

	namespace ukm {
	class UkmRecorder;
	} // namespace ukm

	namespace blink {

	// A (generic) wrapper around IdentifiableToken to enable its use as a HashMap
	// key. The \|token\| represents the parameters by which a font was looked up.
	// However, if \|is_deleted_value\| or \|is_empty_value\|, this key represents an
	// object for HashMap's internal use only. In that case, \|token\| is left as a
	// default value.
	struct IdentifiableTokenKey {
	IdentifiableToken token;
	bool is_deleted_value = false;
	bool is_empty_value = false;

	IdentifiableTokenKey() : is_empty_value(true) {}
	explicit IdentifiableTokenKey(const IdentifiableToken& token)
	: token(token) {}
	explicit IdentifiableTokenKey(WTF::HashTableDeletedValueType)
	: is_deleted_value(true) {}

	bool IsHashTableDeletedValue() const { return is_deleted_value; }

	bool operator==(const IdentifiableTokenKey& other) const {
	return token == other.token && is_deleted_value == other.is_deleted_value &&
	is_empty_value == other.is_empty_value;
	}
	bool operator!=(const IdentifiableTokenKey& other) const {
	return !(*this == other);
	}
	};

	// A helper that defines the hash and equality functions that HashMap should use
	// internally for comparing IdentifiableTokenKeys.
	struct IdentifiableTokenKeyHash {
	STATIC_ONLY(IdentifiableTokenKeyHash);
	static unsigned GetHash(const IdentifiableTokenKey& key) {
	IntHash<int64_t> hasher;
	return hasher.GetHash(key.token.ToUkmMetricValue()) ^
	hasher.GetHash((key.is_deleted_value << 1) + key.is_empty_value);
	}
	static bool Equal(const IdentifiableTokenKey& a,
	const IdentifiableTokenKey& b) {
	return a == b;
	}
	static const bool safe_to_compare_to_empty_or_deleted = true;
	};

	// A helper that defines the invalid 'empty value' that HashMap should use
	// internally.
	struct IdentifiableTokenKeyHashTraits
	: WTF::SimpleClassHashTraits<IdentifiableTokenKey> {
	STATIC_ONLY(IdentifiableTokenKeyHashTraits);
	static const bool kEmptyValueIsZero = false;
	static IdentifiableTokenKey EmptyValue() { return IdentifiableTokenKey(); }
	};

	// Tracks and reports UKM metrics of attempted font family match attempts (both
	// successful and not successful) by the current frame.
	//
	// The number of successful / not successful font family match attempts are
	// reported to UKM. The class de-dupes attempts to match the same font family
	// name such that they are counted as one attempt.
	//
	// Each local font lookup is also reported as is each mapping of generic font
	// family name to its corresponding actual font family names. Local font lookups
	// are deduped according to the family name looked up in the FontCache and the
	// FontSelectionRequest parameters (i.e. weight, width and slope). Generic font
	// family lookups are de-duped according to the generic name, the
	// GenericFamilyType and the script. Both types of lookup events are reported
	// regularly.
	class PLATFORM_EXPORT FontMatchingMetrics {
	public:
	enum FontLoadContext { kTopLevelFrame = 0, kSubframe, kWorker };

	// Create a FontMatchingMetrics objects for a frame, with \|top_level\|
	// indicating whether it is a mainframe.
	FontMatchingMetrics(bool top_level,
	ukm::UkmRecorder* ukm_recorder,
	ukm::SourceId source_id,
	scoped_refptr<base::SingleThreadTaskRunner> task_runner);

	// Create a FontMatchingMetrics objects for a worker.
	FontMatchingMetrics(ukm::UkmRecorder* ukm_recorder,
	ukm::SourceId source_id,
	scoped_refptr<base::SingleThreadTaskRunner> task_runner);

	// Called when a page attempts to match a font family, and the font family is
	// available.
	void ReportSuccessfulFontFamilyMatch(const AtomicString& font_family_name);

	// Called when a page attempts to match a font family, and the font family is
	// not available.
	void ReportFailedFontFamilyMatch(const AtomicString& font_family_name);

	// Called when a page attempts to match a system font family.
	void ReportSystemFontFamily(const AtomicString& font_family_name);

	// Called when a page attempts to match a web font family.
	void ReportWebFontFamily(const AtomicString& font_family_name);

	// Reports a font listed in a @font-face src:local rule that successfully
	// matched.
	void ReportSuccessfulLocalFontMatch(const AtomicString& font_name);

	// Reports a font listed in a @font-face src:local rule that didn't
	// successfully match.
	void ReportFailedLocalFontMatch(const AtomicString& font_name);

	// Reports a local font was looked up by a name and font description. This
	// only includes lookups where the name is allowed to match family names,
	// PostScript names and full font names.
	void ReportFontLookupByUniqueOrFamilyName(
	const AtomicString& name,
	const FontDescription& font_description,
	SimpleFontData* resulting_font_data);

	// Reports a local font was looked up by a name and font description. This
	// only includes lookups where the name is allowed to match PostScript names
	// and full font names, but not family names.
	void ReportFontLookupByUniqueNameOnly(const AtomicString& name,
	const FontDescription& font_description,
	SimpleFontData* resulting_font_data,
	bool is_loading_fallback = false);

	// Reports a font was looked up by a fallback character, fallback priority,
	// and a font description.
	void ReportFontLookupByFallbackCharacter(
	UChar32 fallback_character,
	FontFallbackPriority fallback_priority,
	const FontDescription& font_description,
	SimpleFontData* resulting_font_data);

	// Reports a last-resort fallback font was looked up by a font description.
	void ReportLastResortFallbackFontLookup(
	const FontDescription& font_description,
	SimpleFontData* resulting_font_data);

	// Reports a generic font family name was matched according to the script and
	// the user's preferences to a font family name.
	void ReportFontFamilyLookupByGenericFamily(
	const AtomicString& generic_font_family_name,
	UScriptCode script,
	FontDescription::GenericFamilyType generic_family_type,
	const AtomicString& resulting_font_name);

	// Called on page unload and forces metrics to be flushed.
	void PublishAllMetrics();

	// Called whenever a font lookup event that will be saved in \|font_tracker\| or
	// \|user_font_preference_mapping\| occurs.
	void OnFontLookup();

	// Publishes the font lookup events. Recorded on document shutdown/worker
	// destruction and every minute, as long as additional lookups are occurring.
	void PublishIdentifiabilityMetrics();

	// Publishes the number of font family matches attempted (both successful
	// and otherwise) to UKM. Recorded on page unload.
	void PublishUkmMetrics();

	private:
	void IdentifiabilityMetricsTimerFired(TimerBase*);

	// This HashMap generically stores details of font lookups, i.e. what was used
	// to search for the font, and what the resulting font was. The key is an
	// IdentifiableTokenKey representing a wrapper around a digest of the lookup
	// parameters. The value is an IdentifiableToken representing either a digest
	// of the returned typeface or 0, if no valid typeface was found.
	using TokenToTokenHashMap = HashMap<IdentifiableTokenKey,
	IdentifiableToken,
	IdentifiableTokenKeyHash,
	IdentifiableTokenKeyHashTraits>;

	// Adds a digest of the \|font_data\|'s typeface to \|hash_map\| using the key
	// \|input_key\|, unless that key is already present. If \|font_data\| is not
	// nullptr, then the typeface digest will also be saved with its PostScript
	// name in \|font_load_postscript_name_\|.
	void InsertFontHashIntoMap(IdentifiableTokenKey input_key,
	SimpleFontData* font_data,
	TokenToTokenHashMap& hash_map);

	// Reports a local font's existence was looked up by a name, but its actual
	// font data may or may not have been loaded. This only includes lookups where
	// the name is allowed to match PostScript names and full font names, but not
	// family names.
	void ReportLocalFontExistenceByUniqueNameOnly(const AtomicString& font_name,
	bool font_exists);

	// Constructs a builder with a hash of the FontSelectionRequest already added.
	IdentifiableTokenBuilder GetTokenBuilderWithFontSelectionRequest(
	const FontDescription& font_description);

	// Get a hash that uniquely represents the font data. Returns 0 if \|font_data\|
	// is nullptr.
	int64_t GetHashForFontData(SimpleFontData* font_data);

	void Initialize();

	// Get a token that uniquely represents the typeface's PostScript name. May
	// represent the empty string if no PostScript name was found.
	IdentifiableToken GetPostScriptNameTokenForFontData(
	SimpleFontData* font_data);

	// Font family names successfully matched.
	HashSet<AtomicString> successful_font_families_;

	// Font family names that weren't successfully matched.
	HashSet<AtomicString> failed_font_families_;

	// System font families the page attempted to match.
	HashSet<AtomicString> system_font_families_;

	// Web font families the page attempted to match.
	HashSet<AtomicString> web_font_families_;

	// @font-face src:local fonts that successfully matched.
	HashSet<AtomicString> local_fonts_succeeded_;

	// @font-face src:local fonts that didn't successfully match.
	HashSet<AtomicString> local_fonts_failed_;

	// Indicates whether this FontMatchingMetrics instance is for a top-level
	// frame, a subframe or a worker.
	const FontLoadContext load_context_;

	TokenToTokenHashMap font_lookups_by_unique_or_family_name_;
	TokenToTokenHashMap font_lookups_by_unique_name_only_;
	TokenToTokenHashMap font_lookups_by_fallback_character_;
	TokenToTokenHashMap font_lookups_as_last_resort_;
	TokenToTokenHashMap generic_font_lookups_;
	TokenToTokenHashMap font_load_postscript_name_;
	TokenToTokenHashMap local_font_existence_by_unique_name_only_;

	ukm::UkmRecorder* const ukm_recorder_;
	const ukm::SourceId source_id_;

	TaskRunnerTimer<FontMatchingMetrics> identifiability_metrics_timer_;
	};

	} // namespace blink

	#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_MATCHING_METRICS_H_