Cleanup budget_database based on evolving API.

chrome/browser/budget_service/budget_database.h

 // 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.
 
 #ifndef CHROME_BROWSER_BUDGET_SERVICE_BUDGET_DATABASE_H_
 #define CHROME_BROWSER_BUDGET_SERVICE_BUDGET_DATABASE_H_
 
 #include <list>
 #include <memory>
 #include <unordered_map>
@@ skipping 13 matching lines @@
 namespace budget_service {
 class Budget;
 }
 
 class GURL;
 
 // A class used to asynchronously read and write details of the budget
 // assigned to an origin. The class uses an underlying LevelDB.
 class BudgetDatabase {
  public:
+  // Data structure to hold information about the budget at particular points in
+  // time in the future.
+  struct BudgetStatus {
+    BudgetStatus(double budget_at, base::Time time)
+        : budget_at(budget_at), time(time) {}
+    BudgetStatus(const BudgetStatus& other)
+        : budget_at(other.budget_at), time(other.time) {}
+
+    double budget_at;
+    base::Time time;
+  };
+
   // Data structure for returing the budget decay expectations to the caller.
-  using BudgetExpectation = std::list<std::pair<double, base::Time>>;
+  using BudgetExpectation = std::list<BudgetStatus>;
 
   // Callback for setting a budget value.
   using StoreBudgetCallback = base::Callback<void(bool success)>;
 
   // Callback for getting a list of all budget chunks.
-  using GetBudgetDetailsCallback = base::Callback<
-      void(bool success, double debt, const BudgetExpectation& expectation)>;
+  using GetBudgetDetailsCallback =
+      base::Callback<void(bool success, const BudgetExpectation& expectation)>;
 
   // The database_dir specifies the location of the budget information on
   // disk. The task_runner is used by the ProtoDatabase to handle all blocking
   // calls and disk access.
   BudgetDatabase(const base::FilePath& database_dir,
                  const scoped_refptr<base::SequencedTaskRunner>& task_runner);
   ~BudgetDatabase();
 
-  // Get the full budget expectation for the origin. This will return any
-  // debt as well as a sequence of time points and the expected budget at
-  // those times.
+  // Get the full budget expectation for the origin. This will return a
+  // sequence of time points and the expected budget at those times.
   void GetBudgetDetails(const GURL& origin,
                         const GetBudgetDetailsCallback& callback);
 
   // Add budget for an origin. The caller specifies the amount, and the method
   // adds the amount to the cache with the correct expiration. Callback is
   // invoked only after the newly cached value is written to storage. This
   // should only be called after the budget has been read from the database.
   void AddBudget(const GURL& origin,
                  double amount,
                  const StoreBudgetCallback& callback);
 
  private:
   friend class BudgetDatabaseTest;
 
   // Used to allow tests to change time for testing.
   void SetClockForTesting(std::unique_ptr<base::Clock> clock);
 
+  // Holds information about individual pieces of awarded budget. There is a
+  // one-to-one mapping of these to the chunks in the underlying database.
+  struct BudgetChunk {

[Peter Beverloo, 2016/08/10 15:36:45]

I think it would be good to be very explicit in documenting how BudgetStatus and
BudgetChunk differ, since they *seem* to contain the same information.

[harkness, 2016/08/10 16:41:55]

Agreed. I expanded the description of BudgetStatus which should clarify things.

+    BudgetChunk(double amount, base::Time expiration)
+        : amount(amount), expiration(expiration) {}
+    BudgetChunk(const BudgetChunk& other)
+        : amount(other.amount), expiration(other.expiration) {}
+
+    double amount;
+    base::Time expiration;
+  };
+
   // Data structure for caching budget information.
-  using BudgetChunks = std::vector<std::pair<double, base::Time>>;
-  using BudgetInfo = std::pair<double, BudgetChunks>;
+  using BudgetChunks = std::vector<BudgetChunk>;
 
   using AddToCacheCallback = base::Callback<void(bool success)>;
 
   void OnDatabaseInit(bool success);
 
   bool IsCached(const GURL& origin) const;
 
   void AddToCache(const GURL& origin,
                   const AddToCacheCallback& callback,
                   bool success,
                   std::unique_ptr<budget_service::Budget> budget);
 
   void DidGetBudget(const GURL& origin,
                     const GetBudgetDetailsCallback& callback,
                     bool success);
 
   void WriteCachedValuesToDatabase(const GURL& origin,
                                    const StoreBudgetCallback& callback);
 
   void CleanupExpiredBudget(const GURL& origin);
 
   // The database for storing budget information.
   std::unique_ptr<leveldb_proto::ProtoDatabase<budget_service::Budget>> db_;
 
   // Cached data for the origins which have been loaded.
-  std::unordered_map<std::string, BudgetInfo> budget_map_;
+  std::unordered_map<std::string, BudgetChunks> budget_map_;
 
   // The clock used to vend times.
   std::unique_ptr<base::Clock> clock_;
 
   base::WeakPtrFactory<BudgetDatabase> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BudgetDatabase);
 };
 
 #endif  // CHROME_BROWSER_BUDGET_SERVICE_BUDGET_DATABASE_H_