[BlobAsync] Disk support for blob storage

storage/browser/blob/blob_storage_registry.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_BLOB_STORAGE_REGISTRY_H_
 #define STORAGE_BROWSER_BLOB_BLOB_STORAGE_REGISTRY_H_
 
 #include <stddef.h>
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/macros.h"
+#include "storage/browser/blob/blob_data_handle.h"
+#include "storage/browser/blob/blob_memory_controller.h"
 #include "storage/browser/blob/internal_blob_data.h"
 #include "storage/browser/storage_browser_export.h"
 #include "storage/common/blob_storage/blob_storage_constants.h"
 
 class GURL;
 
 namespace storage {
 
 // This class stores the blob data in the various states of construction, as
 // well as URL mappings to blob uuids.
@@ skipping 13 matching lines @@
     // The blob is pending transportation from the renderer. This is the default
     // state on entry construction.
     PENDING,
     // The blob is complete and can be read from.
     COMPLETE,
     // The blob is broken and no longer holds data. This happens when there was
     // a problem constructing the blob, or we've run out of memory.
     BROKEN
   };
 
+  struct STORAGE_EXPORT ItemCopyEntry {
+    ItemCopyEntry(scoped_refptr<ShareableBlobDataItem> source_item,
+                  size_t source_item_offset,
+                  scoped_refptr<ShareableBlobDataItem> dest_item);
+    ~ItemCopyEntry();
+    ItemCopyEntry(const ItemCopyEntry&);
+
+    scoped_refptr<ShareableBlobDataItem> source_item;
+    size_t source_item_offset = 0;
+    scoped_refptr<ShareableBlobDataItem> dest_item;
+  };
+
   struct STORAGE_EXPORT Entry {
-    size_t refcount;
-    BlobState state;
+    size_t refcount = 1;
+    BlobState state = BlobState::PENDING;
     std::vector<BlobConstructedCallback> build_completion_callbacks;
 
     // Only applicable if the state == BROKEN.
     IPCBlobCreationCancelCode broken_reason =
         IPCBlobCreationCancelCode::UNKNOWN;
 
-    // data and data_builder are mutually exclusive.
-    std::unique_ptr<InternalBlobData> data;
-    std::unique_ptr<InternalBlobData::Builder> data_builder;
+    // Blob items. During construction these can be
+    InternalBlobData data;
+    bool waiting_until_user_population = false;
+    BlobConstructedCallback ready_for_user_population_callback;
 
+    // Metadata
     std::string content_type;
     std::string content_disposition;
 
-    Entry() = delete;
-    Entry(int refcount, BlobState state);
+    bool can_fit = true;
+    BlobMemoryController::PendingContructionEntry pending_copies_memory_entry;
+    // These are copies from a referenced blob item to our blob items. Some of
+    // these entries may have changed from bytes to files if they were paged.
+    // We must handle this case.
+    std::vector<ItemCopyEntry> copies;
+
+    std::vector<std::unique_ptr<BlobDataHandle>> dependent_blobs;
+    size_t dependent_blobs_building = 0;
+
+    Entry();
     ~Entry();
-
-    // Performs a test-and-set on the state of the given blob. If the state
-    // isn't as expected, we return false. Otherwise we set the new state and
-    // return true.
-    bool TestAndSetState(BlobState expected, BlobState set);
   };
 
   BlobStorageRegistry();
   ~BlobStorageRegistry();
 
   // Creates the blob entry with a refcount of 1 and a state of PENDING. If
   // the blob is already in use, we return null.
   Entry* CreateEntry(const std::string& uuid,
                      const std::string& content_type,
                      const std::string& content_disposition);
@@ skipping 33 matching lines @@
   using URLMap = std::map<GURL, std::string>;
 
   BlobMap blob_map_;
   URLMap url_to_uuid_;
 
   DISALLOW_COPY_AND_ASSIGN(BlobStorageRegistry);
 };
 
 }  // namespace storage
 #endif  // STORAGE_BROWSER_BLOB_BLOB_STORAGE_REGISTRY_H_