[BlobAsync] Disk support for blob storage

storage/browser/blob/internal_blob_data.h

 // Copyright 2015 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 STORAGE_BROWSER_BLOB_INTERNAL_BLOB_DATA_H_
 #define STORAGE_BROWSER_BLOB_INTERNAL_BLOB_DATA_H_
 
 #include <stddef.h>
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "storage/browser/blob/shareable_blob_data_item.h"
 
 namespace storage {
 class ViewBlobInternalsJob;
 
-// This class represents a blob in the BlobStorageContext.  It is constructed
-// using the internal Builder class.
+// This class represents a blob in the BlobStorageContext.
 class InternalBlobData {
  public:
   ~InternalBlobData();
 
  protected:
   friend class BlobStorageContext;
   friend class BlobStorageRegistry;
   friend class ViewBlobInternalsJob;
+  friend class BlobFlattener;
+  friend class BlobSlice;
+
+  InternalBlobData();
+
+  // Appends
+  void AppendSharedBlobItem(const std::string& my_uuid,
+                            scoped_refptr<ShareableBlobDataItem> item);
 
   // Removes the given blob uuid from the internal ShareableBlobDataItems.
   // This is called when this blob is being destroyed.
   void RemoveBlobFromShareableItems(const std::string& blob_uuid);
 
   const std::vector<scoped_refptr<ShareableBlobDataItem>>& items() const;
+  const std::vector<size_t>& offsets() const { return offsets_; }
 
   // Gets the memory used by this blob that is not shared by other blobs. This
   // also doesn't count duplicate items.
   size_t GetUnsharedMemoryUsage() const;
 
-  // Gets the memory used by this blob.  Total memory includes memory of items
-  // possibly shared with other blobs, or items that appear multiple times in
-  // this blob. Unshared memory is memory used by this blob that is not shared
-  // by other blobs.
-  void GetMemoryUsage(size_t* total_memory, size_t* unshared_memory);
+  // Total size of this blob in bytes.
+  uint64_t total_size() { return size_; };
+
+  // Size of this blob that isn't shared from another blob.
+  uint64_t unique_size() { return size_; };
 
  private:
   friend class Builder;
-  InternalBlobData();
+  friend class BlobStorageContext;
 
-  std::string content_type_;
-  std::string content_disposition_;
   std::vector<scoped_refptr<ShareableBlobDataItem>> items_;
 
-  class Builder {
-   public:
-    Builder();
-    ~Builder();
+  // Size in bytes. If we're a single file then this can be uint64_max.
+  uint64_t size_ = 0;
+  // Size of the data copying from other blobs.
+  uint64_t copying_size_ = 0;
 
-    void AppendSharedBlobItem(scoped_refptr<ShareableBlobDataItem> item);
-
-    // Gets the memory used by this builder that is not shared with other blobs.
-    size_t GetNonsharedMemoryUsage() const;
-
-    // Removes the given blob uuid from the internal ShareableBlobDataItems.
-    // This is called on destruction of the blob if we're still building it.
-    void RemoveBlobFromShareableItems(const std::string& blob_uuid);
-
-    // The builder is invalid after calling this method.
-    std::unique_ptr<::storage::InternalBlobData> Build();
-
-   private:
-    std::unique_ptr<::storage::InternalBlobData> data_;
-
-    DISALLOW_COPY_AND_ASSIGN(Builder);
-  };
+  // Only populated if len(items_) > 1.  Used for binary search.
+  // Since the offset of the first item is always 0, we exclude this.
+  std::vector<uint64_t> offsets_;
 
   DISALLOW_COPY_AND_ASSIGN(InternalBlobData);
 };
 
 }  // namespace storage
 #endif  // STORAGE_BROWSER_BLOB_INTERNAL_BLOB_DATA_H_