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// Copyright (c) 2013 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_CONTEXT_H_
#define STORAGE_BROWSER_BLOB_BLOB_STORAGE_CONTEXT_H_
#include <map>
#include <string>
#include <vector>
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "storage/browser/blob/blob_data_handle.h"
#include "storage/browser/blob/blob_data_item.h"
#include "storage/browser/blob/blob_data_snapshot.h"
#include "storage/browser/blob/internal_blob_data.h"
#include "storage/browser/blob/shareable_blob_data_item.h"
#include "storage/browser/storage_browser_export.h"
#include "storage/common/data_element.h"
class GURL;
namespace base {
class FilePath;
class Time;
}
namespace content {
class BlobStorageHost;
}
namespace storage {
class BlobDataBuilder;
class InternalBlobData;
// This class handles the logistics of blob Storage within the browser process,
// and maintains a mapping from blob uuid to the data. The class is single
// threaded and should only be used on the IO thread.
// In chromium, there is one instance per profile.
class STORAGE_EXPORT BlobStorageContext
: public base::SupportsWeakPtr<BlobStorageContext> {
public:
BlobStorageContext();
~BlobStorageContext();
scoped_ptr<BlobDataHandle> GetBlobDataFromUUID(const std::string& uuid);
scoped_ptr<BlobDataHandle> GetBlobDataFromPublicURL(const GURL& url);
// Useful for coining blobs from within the browser process. If the
// blob cannot be added due to memory consumption, returns NULL.
// A builder should not be used twice to create blobs, as the internal
// resources are refcounted instead of copied for memory efficiency.
// To cleanly use a builder multiple times, please call Clone() on the
// builder, or even better for memory savings, clear the builder and append
// the previously constructed blob.
scoped_ptr<BlobDataHandle> AddFinishedBlob(BlobDataBuilder* builder);
// Useful for coining blob urls from within the browser process.
bool RegisterPublicBlobURL(const GURL& url, const std::string& uuid);
void RevokePublicBlobURL(const GURL& url);
size_t memory_usage() const { return memory_usage_; }
size_t blob_count() const { return blob_map_.size(); }
private:
friend class content::BlobStorageHost;
friend class BlobDataHandle::BlobDataHandleShared;
friend class ViewBlobInternalsJob;
enum EntryFlags {
EXCEEDED_MEMORY = 1 << 1,
};
struct BlobMapEntry {
int refcount;
int flags;
// data and data_builder are mutually exclusive.
scoped_ptr<InternalBlobData> data;
scoped_ptr<InternalBlobData::Builder> data_builder;
BlobMapEntry();
BlobMapEntry(int refcount, InternalBlobData::Builder* data);
~BlobMapEntry();
bool IsBeingBuilt();
};
typedef std::map<std::string, BlobMapEntry*> BlobMap;
typedef std::map<GURL, std::string> BlobURLMap;
// Called by BlobDataHandle.
scoped_ptr<BlobDataSnapshot> CreateSnapshot(const std::string& uuid);
// ### Methods called by BlobStorageHost ###
void StartBuildingBlob(const std::string& uuid);
void AppendBlobDataItem(const std::string& uuid,
const DataElement& data_item);
void FinishBuildingBlob(const std::string& uuid, const std::string& type);
void CancelBuildingBlob(const std::string& uuid);
void IncrementBlobRefCount(const std::string& uuid);
void DecrementBlobRefCount(const std::string& uuid);
// #########################################
// Flags the entry for exceeding memory, and resets the builder.
void BlobEntryExceededMemory(BlobMapEntry* entry);
// Allocates memory to hold the given data element and copies the data over.
scoped_refptr<BlobDataItem> AllocateBlobItem(const std::string& uuid,
const DataElement& data_item);
// Appends the given blob item to the blob builder. The new blob
// retains ownership of data_item if applicable, and returns false if there
// wasn't enough memory to hold the item.
bool AppendAllocatedBlobItem(const std::string& target_blob_uuid,
scoped_refptr<BlobDataItem> data_item,
InternalBlobData::Builder* target_blob_data);
// Deconstructs the blob and appends it's contents to the target blob. Items
// are shared if possible, and copied if the given offset and length
// have to split an item.
bool AppendBlob(const std::string& target_blob_uuid,
const InternalBlobData& blob,
uint64_t offset,
uint64_t length,
InternalBlobData::Builder* target_blob_data);
bool IsInUse(const std::string& uuid);
bool IsBeingBuilt(const std::string& uuid);
bool IsUrlRegistered(const GURL& blob_url);
BlobMap blob_map_;
BlobURLMap public_blob_urls_;
// Used to keep track of how much memory is being utilized for blob data,
// we count only the items of TYPE_DATA which are held in memory and not
// items of TYPE_FILE.
size_t memory_usage_;
DISALLOW_COPY_AND_ASSIGN(BlobStorageContext);
};
} // namespace storage
#endif // STORAGE_BROWSER_BLOB_BLOB_STORAGE_CONTEXT_H_
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