[CacheStorage] Pad and bin opaque resource sizes.

content/browser/cache_storage/cache_storage_index.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 CONTENT_BROWSER_CACHE_STORAGE_CACHE_STORAGE_INDEX_H_
 #define CONTENT_BROWSER_CACHE_STORAGE_CACHE_STORAGE_INDEX_H_
 
 #include <list>
 #include <string>
 #include <unordered_map>
 
+#include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "content/browser/cache_storage/cache_storage.h"
 
 namespace content {
 
 // CacheStorageIndex maintains an ordered list of metadata (CacheMetadata)
 // for each cache owned by a CacheStorage object. This class is not thread safe,
 // and is owned by the CacheStorage.
 class CONTENT_EXPORT CacheStorageIndex {
  public:
   struct CacheMetadata {
-    CacheMetadata(const std::string& name, int64_t size)
-        : name(name), size(size) {}
+    CacheMetadata(const std::string& name,
+                  int64_t size,
+                  int64_t padding,
+                  const std::string& padding_key)
+        : name(name), size(size), padding(padding), padding_key(padding_key) {}
     std::string name;
     // The size (in bytes) of the cache. Set to CacheStorage::kSizeUnknown if
     // size not known.
     int64_t size;
+
+    // The padding (in bytes) of the cache. Set to CacheStorage::kSizeUnknown
+    // if padding not known.
+    int64_t padding;
+
+    // The HMAC key used to calculate padding for some cache entries.
+    std::string padding_key;
   };
 
   CacheStorageIndex();
   ~CacheStorageIndex();
 
   CacheStorageIndex& operator=(CacheStorageIndex&& rhs);
 
   void Insert(const CacheMetadata& cache_metadata);
   void Delete(const std::string& cache_name);
 
   // Sets the cache size. Returns true if the new size is different than the
   // current size else false.
   bool SetCacheSize(const std::string& cache_name, int64_t size);
 
-  // Return the size (in bytes) of the specified cache. Will return
-  // CacheStorage::kSizeUnknown if the specified cache does not exist.
-  int64_t GetCacheSize(const std::string& cache_name) const;
+  // Find the cache metadata for a given cache name. If not found nullptr is
+  // returned.
+  const CacheMetadata* FindMetadata(const std::string& cache_name) const;
+
+  // Sets the cache padding. Returns true if the new padding is different than
+  // the current padding else false.
+  bool SetCachePadding(const std::string& cache_name, int64_t padding);
 
   const std::list<CacheMetadata>& ordered_cache_metadata() const {
     return ordered_cache_metadata_;
   }
 
   size_t num_entries() const { return ordered_cache_metadata_.size(); }
 
   // Will calculate (if necessary), and return the total sum of all cache sizes.
-  int64_t GetStorageSize();
+  int64_t GetPaddedStorageSize();
 
   // Mark the cache as doomed. This removes the cache metadata from the index.
   // All const methods (eg: num_entries) will behave as if the doomed cache is
   // not present in the index. Prior to calling any non-const method the doomed
   // cache must either be finalized (by calling FinalizeDoomedCache) or restored
   // (by calling RestoreDoomedCache).
   //
   // RestoreDoomedCache restores the metadata to the index at the original
   // position prior to calling DoomCache.
   void DoomCache(const std::string& cache_name);
   void FinalizeDoomedCache();
   void RestoreDoomedCache();
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(CacheStorageIndexTest, TestSetCacheSize);
+  FRIEND_TEST_ALL_PREFIXES(CacheStorageIndexTest, TestSetCachePadding);
+
   void UpdateStorageSize();
+  void UpdateStoragePadding();
   void ClearDoomedCache();
 
+  // Return the size (in bytes) of the specified cache. Will return
+  // CacheStorage::kSizeUnknown if the specified cache does not exist.
+  int64_t GetCacheSize(const std::string& cache_name) const;
+
+  // Return the padding (in bytes) of the specified cache. Will return
+  // CacheStorage::kSizeUnknown if the specified cache does not exist.
+  int64_t GetCachePadding(const std::string& cache_name) const;
+
   // Use a list to keep saved iterators valid during insert/erase.
   // Note: ordered by cache creation.
   std::list<CacheMetadata> ordered_cache_metadata_;
   std::unordered_map<std::string, std::list<CacheMetadata>::iterator>
       cache_metadata_map_;
 
-  // The total size of all caches in this store.
+  // The total unpadded size of all caches in this store.
   int64_t storage_size_ = CacheStorage::kSizeUnknown;
 
+  // The total padding of all caches in this store.
+  int64_t storage_padding_ = CacheStorage::kSizeUnknown;
+
   // The doomed cache metadata saved when calling DoomCache.
   CacheMetadata doomed_cache_metadata_;
   std::list<CacheMetadata>::iterator after_doomed_cache_metadata_;
   bool has_doomed_cache_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(CacheStorageIndex);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_CACHE_STORAGE_CACHE_STORAGE_INDEX_H_