WebStorageArea.h

/*
 * Copyright (C) 2009 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 */

#ifndef WebStorageArea_h
#define WebStorageArea_h

#include "WebCommon.h"
#include "WebString.h"

namespace WebKit {

class WebURL;

class WebStorageArea {
public:
    virtual ~WebStorageArea() { }

    enum Result {
        ResultOK = 0,
        ResultBlockedByQuota
    };

    // The number of key/value pairs in the storage area.
    virtual unsigned length() = 0;

    // Get a value for a specific key. Valid key indices are 0 through length() - 1.
    // Indexes may change on any set/removeItem call. Will return null if the index
    // provided is out of range.
    virtual WebString key(unsigned index) = 0;

    // Get the value that corresponds to a specific key. This returns null if there is
    // no entry for that key.
    virtual WebString getItem(const WebString& key) = 0;

    // Set the value that corresponds to a specific key. Result will either be ResultOK
    // or some particular error. The value is NOT set when there's an error. |pageUrl| is the
    // url that should be used if a storage event fires.
    virtual void setItem(const WebString& key, const WebString& newValue, const WebURL& pageUrl, Result& result)
    {
        WebString unused;
        setItem(key, newValue, pageUrl, result, unused);
    }


    // Remove the value associated with a particular key. |pageUrl| is the url that should be used
    // if a storage event fires.
    virtual void removeItem(const WebString& key, const WebURL& pageUrl)
    {
        WebString unused;
        removeItem(key, pageUrl, unused);
    }

    // Clear all key/value pairs. |pageUrl| is the url that should be used if a storage event fires.
    virtual void clear(const WebURL& pageUrl)
    {
        bool unused;
        clear(pageUrl, unused);
    }

    // Returns amount of bytes occupied by the storage cache in physical memory.
    virtual size_t memoryBytesUsedByCache() const { return 0; }

    // DEPRECATED - being replaced by the async variants above which do not return oldValues or block until completion.
    virtual void setItem(const WebString& key, const WebString& newValue, const WebURL&, Result&, WebString& oldValue) { }
    virtual void removeItem(const WebString& key, const WebURL& pageUrl, WebString& oldValue)  { }
    virtual void clear(const WebURL& pageUrl, bool& somethingCleared)  { }
};

} // namespace WebKit

#endif // WebStorageArea_h