Write out CacheStorageCache size to index file.

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/macros.h"
+#include "content/browser/cache_storage/cache_storage.h"
+
+namespace content {
+
+class CacheMetadata;
+
+// 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) {}
+    std::string name;
+    // The size (in bytes) of the cache. Set to CacheStorage::kSizeUnknown if
+    // size not known.
+    int64_t size;
+  };
+
+  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;
+
+  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();
+
+  // Mark the cache as doomed. This will remove the cache metadata from the

[jkarlin, 2016/12/19 17:48:15]

This needs a bit more documentation. For instance, once this is called you need
to either finalize or restore it before making any other modifications.

[cmumford, 2016/12/19 19:25:57]

Done.

+  // index. To completely delete the metadata via FinalizeDoomedCache, and use

[jkarlin, 2016/12/19 17:48:15]

s/via/call/ 

[cmumford, 2016/12/19 19:25:57]

Done.

+  // ResetDoomedCache to restore the metadata to the index at the original
+  // position.
+  void DoomCache(const std::string& cache_name);
+  void FinalizeDoomedCache();
+  void ResetDoomedCache();

[jkarlin, 2016/12/19 17:48:15]

RestoreDoomedCache? RevertDoomedCache?

[cmumford, 2016/12/19 19:25:57]

I went with RestoreDoomedCache.

+
+ private:
+  void UpdateStorageSize();
+  void ClearDoomedCache();
+
+  // 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.
+  int64_t storage_size_ = 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_