chrome/browser/budget_service/budget_database.cc - chromium/src - Git at Google

 // Copyright 2016 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.

 #include "chrome/browser/budget_service/budget_database.h"

 #include "base/containers/adapters.h"
 #include "base/time/clock.h"
 #include "base/time/default_clock.h"
 #include "chrome/browser/budget_service/budget.pb.h"
 #include "components/leveldb_proto/proto_database_impl.h"
 #include "content/public/browser/browser_thread.h"
 #include "url/gurl.h"

 using content::BrowserThread;

 namespace {

 // UMA are logged for the database with this string as part of the name.
 // They will be LevelDB.*.BudgetManager. Changes here should be synchronized
 // with histograms.xml.
 const char kDatabaseUMAName[] = "BudgetManager";

 // The default amount of time during which a budget will be valid.
 // This is 3 days = 72 hours.
 constexpr double kBudgetDurationInHours = 72;

 }  // namespace

 BudgetDatabase::BudgetInfo::BudgetInfo() {}

 BudgetDatabase::BudgetInfo::BudgetInfo(const BudgetInfo&& other)
     : last_engagement_award(other.last_engagement_award) {
   chunks = std::move(other.chunks);
 }

 BudgetDatabase::BudgetInfo::~BudgetInfo() {}

 BudgetDatabase::BudgetDatabase(
     const base::FilePath& database_dir,
     const scoped_refptr<base::SequencedTaskRunner>& task_runner)
     : db_(new leveldb_proto::ProtoDatabaseImpl<budget_service::Budget>(
           task_runner)),
       clock_(base::WrapUnique(new base::DefaultClock)),
       weak_ptr_factory_(this) {
   db_->Init(kDatabaseUMAName, database_dir,
             base::Bind(&BudgetDatabase::OnDatabaseInit,
                        weak_ptr_factory_.GetWeakPtr()));
 }

 BudgetDatabase::~BudgetDatabase() {}

 void BudgetDatabase::GetBudgetDetails(
     const GURL& origin,
     const GetBudgetDetailsCallback& callback) {
   DCHECK_EQ(origin.GetOrigin(), origin);

   // If this origin is already in the cache, immediately return the data.
   if (IsCached(origin)) {
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
                             base::Bind(&BudgetDatabase::DidGetBudget,
                                        weak_ptr_factory_.GetWeakPtr(), origin,
                                        callback, true /* success */));
     return;
   }

   // Otherwise, query for the data, add it to the cache, then return the result.
   AddToCacheCallback cache_callback =
       base::Bind(&BudgetDatabase::DidGetBudget, weak_ptr_factory_.GetWeakPtr(),
                  origin, callback);
   db_->GetEntry(origin.spec(), base::Bind(&BudgetDatabase::AddToCache,
                                           weak_ptr_factory_.GetWeakPtr(),
                                           origin, cache_callback));
 }

 void BudgetDatabase::AddBudget(const GURL& origin,
                                double amount,
                                const StoreBudgetCallback& callback) {
   DCHECK_EQ(origin.GetOrigin(), origin);

   // Add a new chunk of budget for the origin at the default expiration time.
   base::Time expiration =
       clock_->Now() + base::TimeDelta::FromHours(kBudgetDurationInHours);
   budget_map_[origin.spec()].chunks.emplace_back(amount, expiration);

   // Now that the cache is updated, write the data to the database.
   WriteCachedValuesToDatabase(origin, callback);
 }

 void BudgetDatabase::AddEngagementBudget(const GURL& origin,
                                          double score,
                                          const StoreBudgetCallback& callback) {
   DCHECK_EQ(origin.GetOrigin(), origin);

   // By default we award the "full" award. Then that ratio is decreased if
   // there have been other awards recently.
   double ratio = 1.0;

   // Calculate how much budget should be awarded. If the origin is not cached,
   // then we award a full amount.
   if (IsCached(origin)) {
     base::TimeDelta elapsed =
         clock_->Now() - budget_map_[origin.spec()].last_engagement_award;
     int elapsed_hours = elapsed.InHours();
     if (elapsed_hours == 0) {
       // Don't give engagement awards for periods less than an hour.
       callback.Run(true);
       return;
     }
     if (elapsed_hours < kBudgetDurationInHours)
       ratio = elapsed_hours / kBudgetDurationInHours;
   }

   // Update the last_engagement_award to the current time. If the origin wasn't
   // already in the map, this adds a new entry for it.
   budget_map_[origin.spec()].last_engagement_award = clock_->Now();

   // Pass to the base AddBudget to update the cache and write to the database.
   AddBudget(origin, score * ratio, callback);
 }

 void BudgetDatabase::SpendBudget(const GURL& origin,
                                  double amount,
                                  const StoreBudgetCallback& callback) {
   DCHECK_EQ(origin.GetOrigin(), origin);

   // First, cleanup any expired budget chunks for the origin.
   CleanupExpiredBudget(origin);

   if (!IsCached(origin)) {
     callback.Run(false);
     return;
   }

   // Walk the list of budget chunks to see if the origin has enough budget.
   double total = 0;
   BudgetInfo& info = budget_map_[origin.spec()];
   for (const BudgetChunk& chunk : info.chunks)
     total += chunk.amount;

   if (total < amount) {
     callback.Run(false);
     return;
   }

   // Walk the chunks and remove enough budget to cover the needed amount.
   double bill = amount;
   for (auto iter = info.chunks.begin(); iter != info.chunks.end();) {
     if (iter->amount > bill) {
       iter->amount -= bill;
       bill = 0;
       ++iter;
       break;
     }
     bill -= iter->amount;
     iter = info.chunks.erase(iter);
   }

   // There should have been enough budget to cover the entire bill.
   DCHECK_EQ(0, bill);

   // Now that the cache is updated, write the data to the database.
   // TODO(harkness): Consider adding a second parameter to the callback so the
   // caller can distinguish between not enough budget and a failed database
   // write.
   // TODO(harkness): If the database write fails, the cache will be out of sync
   // with the database. Consider ways to mitigate this.
   WriteCachedValuesToDatabase(origin, callback);
 }

 void BudgetDatabase::OnDatabaseInit(bool success) {
   // TODO(harkness): Consider caching the budget database now?
 }

 bool BudgetDatabase::IsCached(const GURL& origin) const {
   return budget_map_.find(origin.spec()) != budget_map_.end();
 }

 void BudgetDatabase::AddToCache(
     const GURL& origin,
     const AddToCacheCallback& callback,
     bool success,
     std::unique_ptr<budget_service::Budget> budget_proto) {
   // If the database read failed, there's nothing to add to the cache.
   if (!success || !budget_proto) {
     callback.Run(success);
     return;
   }

   // Add the data to the cache, converting from the proto format to an STL
   // format which is better for removing things from the list.
   BudgetInfo& info = budget_map_[origin.spec()];
   for (const auto& chunk : budget_proto->budget()) {
     info.chunks.emplace_back(chunk.amount(),
                              base::Time::FromInternalValue(chunk.expiration()));
   }

   info.last_engagement_award =
       base::Time::FromInternalValue(budget_proto->engagement_last_updated());

   callback.Run(success);
 }

 void BudgetDatabase::DidGetBudget(const GURL& origin,
                                   const GetBudgetDetailsCallback& callback,
                                   bool success) {
   // If the database wasn't able to read the information, return the
   // failure and an empty BudgetPrediction.
   if (!success) {
     callback.Run(success, BudgetPrediction());
     return;
   }

   // First, cleanup any expired budget chunks for the origin.
   CleanupExpiredBudget(origin);

   // Now, build up the BudgetExpection. This is different from the format
   // in which the cache stores the data. The cache stores chunks of budget and
   // when that budget expires. The BudgetPrediction describes a set of times
   // and the budget at those times.
   BudgetPrediction prediction;
   double total = 0;

   if (IsCached(origin)) {
     // Starting with the chunks that expire the farthest in the future, build up
     // the budget predictions for those future times.
     const BudgetChunks& chunks = budget_map_[origin.spec()].chunks;
     for (const auto& chunk : base::Reversed(chunks)) {
       prediction.emplace_front(total, chunk.expiration);
       total += chunk.amount;
     }
   }

   // Always add one entry at the front of the list for the total budget now.
   prediction.emplace_front(total, clock_->Now());

   callback.Run(true /* success */, prediction);
 }

 void BudgetDatabase::SetClockForTesting(std::unique_ptr<base::Clock> clock) {
   clock_ = std::move(clock);
 }

 void BudgetDatabase::WriteCachedValuesToDatabase(
     const GURL& origin,
     const StoreBudgetCallback& callback) {
   // First, cleanup any expired budget chunks for the origin.
   CleanupExpiredBudget(origin);

   // Create the data structures that are passed to the ProtoDatabase.
   std::unique_ptr<
       leveldb_proto::ProtoDatabase<budget_service::Budget>::KeyEntryVector>
       entries(new leveldb_proto::ProtoDatabase<
               budget_service::Budget>::KeyEntryVector());
   std::unique_ptr<std::vector<std::string>> keys_to_remove(
       new std::vector<std::string>());

   // Each operation can either update the existing budget or remove the origin's
   // budget information.
   if (IsCached(origin)) {
     // Build the Budget proto object.
     budget_service::Budget budget;
     const BudgetInfo& info = budget_map_[origin.spec()];
     for (const auto& chunk : info.chunks) {
       budget_service::BudgetChunk* budget_chunk = budget.add_budget();
       budget_chunk->set_amount(chunk.amount);
       budget_chunk->set_expiration(chunk.expiration.ToInternalValue());
     }
     budget.set_engagement_last_updated(
         info.last_engagement_award.ToInternalValue());
     entries->push_back(std::make_pair(origin.spec(), budget));
   } else {
     // If the origin doesn't exist in the cache, this is a remove operation.
     keys_to_remove->push_back(origin.spec());
   }

   // Send the updates to the database.
   db_->UpdateEntries(std::move(entries), std::move(keys_to_remove), callback);
 }

 void BudgetDatabase::CleanupExpiredBudget(const GURL& origin) {
   if (!IsCached(origin))
     return;

   base::Time now = clock_->Now();

   BudgetChunks& chunks = budget_map_[origin.spec()].chunks;
   auto cleanup_iter = chunks.begin();

   // This relies on the list of chunks being in timestamp order.
   while (cleanup_iter != chunks.end() && cleanup_iter->expiration <= now)
     cleanup_iter = chunks.erase(cleanup_iter);

   // If the entire budget is empty now AND there have been no engagements
   // in the last kBudgetDurationInHours hours, remove this from the cache.
   if (chunks.empty() &&
       budget_map_[origin.spec()].last_engagement_award <
           clock_->Now() - base::TimeDelta::FromHours(kBudgetDurationInHours))
     budget_map_.erase(origin.spec());
 }
	// Copyright 2016 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.

	#include "chrome/browser/budget_service/budget_database.h"

	#include "base/containers/adapters.h"
	#include "base/time/clock.h"
	#include "base/time/default_clock.h"
	#include "chrome/browser/budget_service/budget.pb.h"
	#include "components/leveldb_proto/proto_database_impl.h"
	#include "content/public/browser/browser_thread.h"
	#include "url/gurl.h"

	using content::BrowserThread;

	namespace {

	// UMA are logged for the database with this string as part of the name.
	// They will be LevelDB.*.BudgetManager. Changes here should be synchronized
	// with histograms.xml.
	const char kDatabaseUMAName[] = "BudgetManager";

	// The default amount of time during which a budget will be valid.
	// This is 3 days = 72 hours.
	constexpr double kBudgetDurationInHours = 72;

	} // namespace

	BudgetDatabase::BudgetInfo::BudgetInfo() {}

	BudgetDatabase::BudgetInfo::BudgetInfo(const BudgetInfo&& other)
	: last_engagement_award(other.last_engagement_award) {
	chunks = std::move(other.chunks);
	}

	BudgetDatabase::BudgetInfo::~BudgetInfo() {}

	BudgetDatabase::BudgetDatabase(
	const base::FilePath& database_dir,
	const scoped_refptr<base::SequencedTaskRunner>& task_runner)
	: db_(new leveldb_proto::ProtoDatabaseImpl<budget_service::Budget>(
	task_runner)),
	clock_(base::WrapUnique(new base::DefaultClock)),
	weak_ptr_factory_(this) {
	db_->Init(kDatabaseUMAName, database_dir,
	base::Bind(&BudgetDatabase::OnDatabaseInit,
	weak_ptr_factory_.GetWeakPtr()));
	}

	BudgetDatabase::~BudgetDatabase() {}

	void BudgetDatabase::GetBudgetDetails(
	const GURL& origin,
	const GetBudgetDetailsCallback& callback) {
	DCHECK_EQ(origin.GetOrigin(), origin);

	// If this origin is already in the cache, immediately return the data.
	if (IsCached(origin)) {
	BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
	base::Bind(&BudgetDatabase::DidGetBudget,
	weak_ptr_factory_.GetWeakPtr(), origin,
	callback, true /* success */));
	return;
	}

	// Otherwise, query for the data, add it to the cache, then return the result.
	AddToCacheCallback cache_callback =
	base::Bind(&BudgetDatabase::DidGetBudget, weak_ptr_factory_.GetWeakPtr(),
	origin, callback);
	db_->GetEntry(origin.spec(), base::Bind(&BudgetDatabase::AddToCache,
	weak_ptr_factory_.GetWeakPtr(),
	origin, cache_callback));
	}

	void BudgetDatabase::AddBudget(const GURL& origin,
	double amount,
	const StoreBudgetCallback& callback) {
	DCHECK_EQ(origin.GetOrigin(), origin);

	// Add a new chunk of budget for the origin at the default expiration time.
	base::Time expiration =
	clock_->Now() + base::TimeDelta::FromHours(kBudgetDurationInHours);
	budget_map_[origin.spec()].chunks.emplace_back(amount, expiration);

	// Now that the cache is updated, write the data to the database.
	WriteCachedValuesToDatabase(origin, callback);
	}

	void BudgetDatabase::AddEngagementBudget(const GURL& origin,
	double score,
	const StoreBudgetCallback& callback) {
	DCHECK_EQ(origin.GetOrigin(), origin);

	// By default we award the "full" award. Then that ratio is decreased if
	// there have been other awards recently.
	double ratio = 1.0;

	// Calculate how much budget should be awarded. If the origin is not cached,
	// then we award a full amount.
	if (IsCached(origin)) {
	base::TimeDelta elapsed =
	clock_->Now() - budget_map_[origin.spec()].last_engagement_award;
	int elapsed_hours = elapsed.InHours();
	if (elapsed_hours == 0) {
	// Don't give engagement awards for periods less than an hour.
	callback.Run(true);
	return;
	}
	if (elapsed_hours < kBudgetDurationInHours)
	ratio = elapsed_hours / kBudgetDurationInHours;
	}

	// Update the last_engagement_award to the current time. If the origin wasn't
	// already in the map, this adds a new entry for it.
	budget_map_[origin.spec()].last_engagement_award = clock_->Now();

	// Pass to the base AddBudget to update the cache and write to the database.
	AddBudget(origin, score * ratio, callback);
	}

	void BudgetDatabase::SpendBudget(const GURL& origin,
	double amount,
	const StoreBudgetCallback& callback) {
	DCHECK_EQ(origin.GetOrigin(), origin);

	// First, cleanup any expired budget chunks for the origin.
	CleanupExpiredBudget(origin);

	if (!IsCached(origin)) {
	callback.Run(false);
	return;
	}

	// Walk the list of budget chunks to see if the origin has enough budget.
	double total = 0;
	BudgetInfo& info = budget_map_[origin.spec()];
	for (const BudgetChunk& chunk : info.chunks)
	total += chunk.amount;

	if (total < amount) {
	callback.Run(false);
	return;
	}

	// Walk the chunks and remove enough budget to cover the needed amount.
	double bill = amount;
	for (auto iter = info.chunks.begin(); iter != info.chunks.end();) {
	if (iter->amount > bill) {
	iter->amount -= bill;
	bill = 0;
	++iter;
	break;
	}
	bill -= iter->amount;
	iter = info.chunks.erase(iter);
	}

	// There should have been enough budget to cover the entire bill.
	DCHECK_EQ(0, bill);

	// Now that the cache is updated, write the data to the database.
	// TODO(harkness): Consider adding a second parameter to the callback so the
	// caller can distinguish between not enough budget and a failed database
	// write.
	// TODO(harkness): If the database write fails, the cache will be out of sync
	// with the database. Consider ways to mitigate this.
	WriteCachedValuesToDatabase(origin, callback);
	}

	void BudgetDatabase::OnDatabaseInit(bool success) {
	// TODO(harkness): Consider caching the budget database now?
	}

	bool BudgetDatabase::IsCached(const GURL& origin) const {
	return budget_map_.find(origin.spec()) != budget_map_.end();
	}

	void BudgetDatabase::AddToCache(
	const GURL& origin,
	const AddToCacheCallback& callback,
	bool success,
	std::unique_ptr<budget_service::Budget> budget_proto) {
	// If the database read failed, there's nothing to add to the cache.
	if (!success \|\| !budget_proto) {
	callback.Run(success);
	return;
	}

	// Add the data to the cache, converting from the proto format to an STL
	// format which is better for removing things from the list.
	BudgetInfo& info = budget_map_[origin.spec()];
	for (const auto& chunk : budget_proto->budget()) {
	info.chunks.emplace_back(chunk.amount(),
	base::Time::FromInternalValue(chunk.expiration()));
	}

	info.last_engagement_award =
	base::Time::FromInternalValue(budget_proto->engagement_last_updated());

	callback.Run(success);
	}

	void BudgetDatabase::DidGetBudget(const GURL& origin,
	const GetBudgetDetailsCallback& callback,
	bool success) {
	// If the database wasn't able to read the information, return the
	// failure and an empty BudgetPrediction.
	if (!success) {
	callback.Run(success, BudgetPrediction());
	return;
	}

	// First, cleanup any expired budget chunks for the origin.
	CleanupExpiredBudget(origin);

	// Now, build up the BudgetExpection. This is different from the format
	// in which the cache stores the data. The cache stores chunks of budget and
	// when that budget expires. The BudgetPrediction describes a set of times
	// and the budget at those times.
	BudgetPrediction prediction;
	double total = 0;

	if (IsCached(origin)) {
	// Starting with the chunks that expire the farthest in the future, build up
	// the budget predictions for those future times.
	const BudgetChunks& chunks = budget_map_[origin.spec()].chunks;
	for (const auto& chunk : base::Reversed(chunks)) {
	prediction.emplace_front(total, chunk.expiration);
	total += chunk.amount;
	}
	}

	// Always add one entry at the front of the list for the total budget now.
	prediction.emplace_front(total, clock_->Now());

	callback.Run(true /* success */, prediction);
	}

	void BudgetDatabase::SetClockForTesting(std::unique_ptr<base::Clock> clock) {
	clock_ = std::move(clock);
	}

	void BudgetDatabase::WriteCachedValuesToDatabase(
	const GURL& origin,
	const StoreBudgetCallback& callback) {
	// First, cleanup any expired budget chunks for the origin.
	CleanupExpiredBudget(origin);

	// Create the data structures that are passed to the ProtoDatabase.
	std::unique_ptr<
	leveldb_proto::ProtoDatabase<budget_service::Budget>::KeyEntryVector>
	entries(new leveldb_proto::ProtoDatabase<
	budget_service::Budget>::KeyEntryVector());
	std::unique_ptr<std::vector<std::string>> keys_to_remove(
	new std::vector<std::string>());

	// Each operation can either update the existing budget or remove the origin's
	// budget information.
	if (IsCached(origin)) {
	// Build the Budget proto object.
	budget_service::Budget budget;
	const BudgetInfo& info = budget_map_[origin.spec()];
	for (const auto& chunk : info.chunks) {
	budget_service::BudgetChunk* budget_chunk = budget.add_budget();
	budget_chunk->set_amount(chunk.amount);
	budget_chunk->set_expiration(chunk.expiration.ToInternalValue());
	}
	budget.set_engagement_last_updated(
	info.last_engagement_award.ToInternalValue());
	entries->push_back(std::make_pair(origin.spec(), budget));
	} else {
	// If the origin doesn't exist in the cache, this is a remove operation.
	keys_to_remove->push_back(origin.spec());
	}

	// Send the updates to the database.
	db_->UpdateEntries(std::move(entries), std::move(keys_to_remove), callback);
	}

	void BudgetDatabase::CleanupExpiredBudget(const GURL& origin) {
	if (!IsCached(origin))
	return;

	base::Time now = clock_->Now();

	BudgetChunks& chunks = budget_map_[origin.spec()].chunks;
	auto cleanup_iter = chunks.begin();

	// This relies on the list of chunks being in timestamp order.
	while (cleanup_iter != chunks.end() && cleanup_iter->expiration <= now)
	cleanup_iter = chunks.erase(cleanup_iter);

	// If the entire budget is empty now AND there have been no engagements
	// in the last kBudgetDurationInHours hours, remove this from the cache.
	if (chunks.empty() &&
	budget_map_[origin.spec()].last_engagement_award <
	clock_->Now() - base::TimeDelta::FromHours(kBudgetDurationInHours))
	budget_map_.erase(origin.spec());
	}