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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsMsgFolderCache_H
#define nsMsgFolderCache_H
#include "nsIMsgFolderCache.h"
#include "nsIFile.h"
#include "nsITimer.h"
namespace Json {
class Value;
};
/**
* nsMsgFolderCache implements the folder cache, which stores values which
* might be slow for the folder to calculate.
* It persists the cache data by dumping it out to a .json file when changes
* are made. To avoid huge numbers of writes, this autosaving is deferred -
* when a cached value is changed, it'll wait a minute or so before
* writing, to collect any other changes that occur during that time.
* If any changes are outstanding at destruction time, it'll perform an
* immediate save then.
*/
class nsMsgFolderCache : public nsIMsgFolderCache {
public:
friend class nsMsgFolderCacheElement;
nsMsgFolderCache();
NS_DECL_ISUPPORTS
NS_DECL_NSIMSGFOLDERCACHE
protected:
virtual ~nsMsgFolderCache();
nsresult LoadFolderCache(nsIFile* jsonFile);
nsresult SaveFolderCache(nsIFile* jsonFile);
// Flag that a save is required. It'll be deferred by kAutoSaveDelayMs.
void SetModified();
static constexpr uint32_t kSaveDelayMs = 1000 * 60 * 1; // 1 minute.
static void doSave(nsITimer*, void* closure);
// Path to the JSON file backing the cache.
nsCOMPtr<nsIFile> mCacheFile;
// This is our data store. Kept as a Json::Value for ease of saving, but
// it's actually not a bad format for access (it's basically a std::map).
// Using a pointer to allow forward declaration. The json headers aren't
// in the include path for other modules, so we don't want to expose them
// here.
Json::Value* mRoot;
bool mSavePending;
nsCOMPtr<nsITimer> mSaveTimer;
};
#endif
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