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// 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 CONTENT_CHILD_BLOB_STORAGE_BLOB_CONSOLIDATION_H_
#define CONTENT_CHILD_BLOB_STORAGE_BLOB_CONSOLIDATION_H_
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include <set>
#include <string>
#include <vector>
#include "base/logging.h"
#include "base/macros.h"
#include "content/common/content_export.h"
#include "storage/common/data_element.h"
#include "third_party/WebKit/public/platform/WebThreadSafeData.h"
namespace content {
// This class facilitates the consolidation of memory items in blobs. No memory
// is copied to store items in this object. Instead, the memory is copied into
// the external char* array given to the ReadMemory method.
// Features:
// * Add_Item methods for building the blob.
// * consolidated_items for getting the consolidated items. This is
// used to describe the blob to the browser.
// * total_memory to get the total memory size of the blob.
// * ReadMemory for reading arbitrary memory from any consolidated item.
//
// NOTE: this class does not do memory accounting or garbage collecting. The
// memory for the blob sticks around until this class is destructed.
class CONTENT_EXPORT BlobConsolidation {
public:
enum class ReadStatus {
ERROR_UNKNOWN,
ERROR_WRONG_TYPE,
ERROR_OUT_OF_BOUNDS,
OK
};
struct ConsolidatedItem {
ConsolidatedItem();
ConsolidatedItem(storage::DataElement::Type type,
uint64_t offset,
uint64_t length);
ConsolidatedItem(const ConsolidatedItem& other);
~ConsolidatedItem();
storage::DataElement::Type type;
uint64_t offset;
uint64_t length;
base::FilePath path; // For TYPE_FILE.
GURL filesystem_url; // For TYPE_FILE_FILESYSTEM.
double expected_modification_time; // For TYPE_FILE, TYPE_FILE_FILESYSTEM.
std::string blob_uuid; // For TYPE_BLOB.
// 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<size_t> offsets; // For TYPE_BYTES.
std::vector<blink::WebThreadSafeData> data; // For TYPE_BYTES.
};
BlobConsolidation();
~BlobConsolidation();
void AddDataItem(const blink::WebThreadSafeData& data);
void AddFileItem(const base::FilePath& path,
uint64_t offset,
uint64_t length,
double expected_modification_time);
void AddBlobItem(const std::string& uuid, uint64_t offset, uint64_t length);
void AddFileSystemItem(const GURL& url,
uint64_t offset,
uint64_t length,
double expected_modification_time);
// These are the resulting consolidated items, constructed from the Add*
// methods. This configuration is used to describe the data to the browser,
// even though one consolidated memory items can contain multiple data parts.
const std::vector<ConsolidatedItem>& consolidated_items() const {
return consolidated_items_;
}
// These are all of the blobs referenced in the construction of this blob.
const std::set<std::string> referenced_blobs() const {
return referenced_blobs_;
}
size_t total_memory() const { return total_memory_; }
// Reads memory from the given item into the given buffer. Returns:
// * ReadStatus::ERROR if the state or arguments are invalid (see error log),
// * ReadStatus::ERROR_WRONG_TYPE if the item at the index isn't memory,
// * ReadStatus::ERROR_OUT_OF_BOUNDS if index, offset, or size are invalid,
// * ReadStatus::DONE if the memory has been successfully read.
// Precondition: memory_out must be a valid pointer to memory with a size of
// at least consolidated_size.
ReadStatus ReadMemory(size_t consolidated_item_index,
size_t consolidated_offset,
size_t consolidated_size,
void* memory_out);
private:
size_t total_memory_;
std::set<std::string> referenced_blobs_;
std::vector<ConsolidatedItem> consolidated_items_;
DISALLOW_COPY_AND_ASSIGN(BlobConsolidation);
};
} // namespace content
#endif // CONTENT_CHILD_BLOB_STORAGE_BLOB_CONSOLIDATION_H_
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