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/* 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/. */
/**
* Message DB Cache manager
*/
/* :::::::: Constants and Helpers ::::::::::::::: */
const EXPORTED_SYMBOLS = ["msgDBCacheManager"];
var { MailServices } = ChromeUtils.import(
"resource:///modules/MailServices.jsm"
);
var log = console.createInstance({
prefix: "mailnews.database.dbcache",
maxLogLevel: "Warn",
maxLogLevelPref: "mailnews.database.dbcache.loglevel",
});
/**
*/
var DBCACHE_INTERVAL_DEFAULT_MS = 60000; // 1 minute
/* :::::::: The Module ::::::::::::::: */
var msgDBCacheManager = {
_initialized: false,
_msgDBCacheTimer: null,
_msgDBCacheTimerIntervalMS: DBCACHE_INTERVAL_DEFAULT_MS,
_dbService: null,
/**
* This is called on startup
*/
init() {
if (this._initialized) {
return;
}
this._dbService = Cc["@mozilla.org/msgDatabase/msgDBService;1"].getService(
Ci.nsIMsgDBService
);
// we listen for "quit-application-granted" instead of
// "quit-application-requested" because other observers of the
// latter can cancel the shutdown.
Services.obs.addObserver(this, "quit-application-granted");
this.startPeriodicCheck();
this._initialized = true;
},
/* ........ Timer Callback ................*/
_dbCacheCheckTimerCallback() {
msgDBCacheManager.checkCachedDBs();
},
/* ........ Observer Notification Handler ................*/
observe(aSubject, aTopic, aData) {
switch (aTopic) {
// This is observed before any windows start unloading if something other
// than the last 3pane window closing requested the application be
// shutdown. For example, when the user quits via the file menu.
case "quit-application-granted":
Services.obs.removeObserver(this, "quit-application-granted");
this.stopPeriodicCheck();
break;
}
},
/* ........ Public API ................*/
/**
* Stops db cache check
*/
stopPeriodicCheck() {
if (this._dbCacheCheckTimer) {
this._dbCacheCheckTimer.cancel();
delete this._dbCacheCheckTimer;
this._dbCacheCheckTimer = null;
}
},
/**
* Starts periodic db cache check
*/
startPeriodicCheck() {
if (!this._dbCacheCheckTimer) {
this._dbCacheCheckTimer = Cc["@mozilla.org/timer;1"].createInstance(
Ci.nsITimer
);
this._dbCacheCheckTimer.initWithCallback(
this._dbCacheCheckTimerCallback,
this._msgDBCacheTimerIntervalMS,
Ci.nsITimer.TYPE_REPEATING_SLACK
);
}
},
/**
* Checks if any DBs need to be closed due to inactivity or too many of them open.
*/
checkCachedDBs() {
let idleLimit = Services.prefs.getIntPref("mail.db.idle_limit");
let maxOpenDBs = Services.prefs.getIntPref("mail.db.max_open");
// db.lastUseTime below is in microseconds while Date.now and idleLimit pref
// is in milliseconds.
let closeThreshold = (Date.now() - idleLimit) * 1000;
let cachedDBs = this._dbService.openDBs;
log.info(
"Periodic check of cached folder databases (DBs), count=" +
cachedDBs.length
);
// Count databases that are already closed or get closed now due to inactivity.
let numClosing = 0;
// Count databases whose folder is open in a window.
let numOpenInWindow = 0;
let dbs = [];
for (let db of cachedDBs) {
if (!db.folder?.databaseOpen) {
// The DB isn't really open anymore.
log.debug("Skipping, DB not open for folder: " + db.folder?.name);
numClosing++;
continue;
}
if (MailServices.mailSession.IsFolderOpenInWindow(db.folder)) {
// The folder is open in a window so this DB must not be closed.
log.debug("Skipping, DB open in window for folder: " + db.folder.name);
numOpenInWindow++;
continue;
}
if (db.lastUseTime < closeThreshold) {
// DB open too log without activity.
log.debug("Closing expired DB for folder: " + db.folder.name);
db.folder.msgDatabase = null;
numClosing++;
continue;
}
// Database eligible for closing.
dbs.push(db);
}
log.info(
"DBs open in a window: " +
numOpenInWindow +
", DBs open: " +
dbs.length +
", DBs already closing: " +
numClosing
);
let dbsToClose = Math.max(
dbs.length - Math.max(maxOpenDBs - numOpenInWindow, 0),
0
);
if (dbsToClose > 0) {
// Close some DBs so that we do not have more than maxOpenDBs.
// However, we skipped DBs for folders that are open in a window
// so if there are so many windows open, it may be possible for
// more than maxOpenDBs folders to stay open after this loop.
log.info("Need to close " + dbsToClose + " more DBs");
// Order databases by lowest lastUseTime (oldest) at the end.
dbs.sort((a, b) => b.lastUseTime - a.lastUseTime);
while (dbsToClose > 0) {
let db = dbs.pop();
log.debug("Closing DB for folder: " + db.folder.name);
db.folder.msgDatabase = null;
dbsToClose--;
}
}
},
};
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