gecko-dev/dom/storage/DOMStorageDBThread.h

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/* -*- Mode: C++; tab-width: 2; 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 DOMStorageDBThread_h___
#define DOMStorageDBThread_h___
#include "prthread.h"
#include "prinrval.h"
#include "nsTArray.h"
#include "mozilla/Monitor.h"
#include "mozilla/storage/StatementCache.h"
#include "nsString.h"
#include "nsCOMPtr.h"
#include "nsClassHashtable.h"
#include "nsIFile.h"
#include "nsIThreadInternal.h"
class mozIStorageConnection;
namespace mozilla {
namespace dom {
class DOMStorageCacheBridge;
class DOMStorageUsageBridge;
class DOMStorageUsage;
typedef mozilla::storage::StatementCache<mozIStorageStatement> StatementCache;
// Interface used by the cache to post operations to the asynchronous
// database thread or process.
class DOMStorageDBBridge
{
public:
DOMStorageDBBridge();
virtual ~DOMStorageDBBridge() {}
// Ensures the database engine is started
virtual nsresult Init() = 0;
// Releases the database and disallows its usage
virtual nsresult Shutdown() = 0;
// Asynchronously fills the cache with data from the database for first use.
// When |aPriority| is true, the preload operation is scheduled as the first one.
// This method is responsible to keep hard reference to the cache for the time of
// the preload or, when preload cannot be performed, call LoadDone() immediately.
virtual void AsyncPreload(DOMStorageCacheBridge* aCache, bool aPriority = false) = 0;
// Asynchronously fill the |usage| object with actual usage of data by its scope.
// The scope is eTLD+1 tops, never deeper subdomains.
virtual void AsyncGetUsage(DOMStorageUsageBridge* aUsage) = 0;
// Synchronously fills the cache, when |aForceSync| is false and cache already got some
// data before, the method waits for the running preload to finish
virtual void SyncPreload(DOMStorageCacheBridge* aCache, bool aForceSync = false) = 0;
// Called when an existing key is modified in the storage, schedules update to the database
virtual nsresult AsyncAddItem(DOMStorageCacheBridge* aCache, const nsAString& aKey, const nsAString& aValue) = 0;
// Called when an existing key is modified in the storage, schedules update to the database
virtual nsresult AsyncUpdateItem(DOMStorageCacheBridge* aCache, const nsAString& aKey, const nsAString& aValue) = 0;
// Called when an item is removed from the storage, schedules delete of the key
virtual nsresult AsyncRemoveItem(DOMStorageCacheBridge* aCache, const nsAString& aKey) = 0;
// Called when the whole storage is cleared by the DOM API, schedules delete of the scope
virtual nsresult AsyncClear(DOMStorageCacheBridge* aCache) = 0;
// Called when chrome deletes e.g. cookies, schedules delete of the whole database
virtual void AsyncClearAll() = 0;
// Called when only a domain and its subdomains or an app data is about to clear
virtual void AsyncClearMatchingScope(const nsACString& aScope) = 0;
// Forces scheduled DB operations to be early flushed to the disk
virtual void AsyncFlush() = 0;
// Check whether the scope has any data stored on disk and is thus allowed to preload
virtual bool ShouldPreloadScope(const nsACString& aScope) = 0;
// Get the complete list of scopes having data
virtual void GetScopesHavingData(InfallibleTArray<nsCString>* aScopes) = 0;
};
// The implementation of the the database engine, this directly works
// with the sqlite or any other db API we are based on
// This class is resposible for collecting and processing asynchronous
// DB operations over caches (DOMStorageCache) communicating though
// DOMStorageCacheBridge interface class
class DOMStorageDBThread final : public DOMStorageDBBridge
{
public:
class PendingOperations;
// Representation of a singe database task, like adding and removing keys,
// (pre)loading the whole origin data, cleaning.
class DBOperation
{
public:
typedef enum {
// Only operation that reads data from the database
opPreload,
// The same as opPreload, just executed with highest priority
opPreloadUrgent,
// Load usage of a scope
opGetUsage,
// Operations invoked by the DOM content API
opAddItem,
opUpdateItem,
opRemoveItem,
opClear,
// Operations invoked by chrome
opClearAll,
opClearMatchingScope,
} OperationType;
explicit DBOperation(const OperationType aType,
DOMStorageCacheBridge* aCache = nullptr,
const nsAString& aKey = EmptyString(),
const nsAString& aValue = EmptyString());
DBOperation(const OperationType aType,
DOMStorageUsageBridge* aUsage);
DBOperation(const OperationType aType,
const nsACString& aScope);
~DBOperation();
// Executes the operation, doesn't necessarity have to be called on the I/O thread
void PerformAndFinalize(DOMStorageDBThread* aThread);
// Finalize the operation, i.e. do any internal cleanup and finish calls
void Finalize(nsresult aRv);
// The operation type
OperationType Type() { return mType; }
// The operation scope (=origin)
const nsCString Scope();
// |Scope + key| the operation is working with
const nsCString Target();
private:
// The operation implementation body
nsresult Perform(DOMStorageDBThread* aThread);
friend class PendingOperations;
OperationType mType;
nsRefPtr<DOMStorageCacheBridge> mCache;
nsRefPtr<DOMStorageUsageBridge> mUsage;
nsString mKey;
nsString mValue;
nsCString mScope;
};
// Encapsulation of collective and coalescing logic for all pending operations
// except preloads that are handled separately as priority operations
class PendingOperations {
public:
PendingOperations();
// Method responsible for coalescing redundant update operations with the same
// |Target()| or clear operations with the same or matching |Scope()|
void Add(DBOperation* aOperation);
// True when there are some scheduled operations to flush on disk
bool HasTasks();
// Moves collected operations to a local flat list to allow execution of the operation
// list out of the thread lock
bool Prepare();
// Executes the previously |Prepared()'ed| list of operations, retuns result, but doesn't
// handle it in any way in case of a failure
nsresult Execute(DOMStorageDBThread* aThread);
// Finalizes the pending operation list, returns false when too many operations failed
// to flush what indicates a long standing issue with the database access.
bool Finalize(nsresult aRv);
// true when a clear that deletes the given |scope| is among the pending operations;
// when a preload for that scope is being scheduled, it must be finished right away
bool IsScopeClearPending(const nsACString& aScope);
// Checks whether there is a pending update (or clear, actually) operation for this scope.
bool IsScopeUpdatePending(const nsACString& aScope);
private:
// Returns true iff new operation is of type newType and there is a pending
// operation of type pendingType for the same key (target).
bool CheckForCoalesceOpportunity(DBOperation* aNewOp,
DBOperation::OperationType aPendingType,
DBOperation::OperationType aNewType);
// List of all clearing operations, executed first
nsClassHashtable<nsCStringHashKey, DBOperation> mClears;
// List of all update/insert operations, executed as second
nsClassHashtable<nsCStringHashKey, DBOperation> mUpdates;
// Collection of all tasks, valid only between Prepare() and Execute()
nsTArray<nsAutoPtr<DBOperation> > mExecList;
// Number of failing flush attempts
uint32_t mFlushFailureCount;
};
class ThreadObserver final : public nsIThreadObserver
{
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSITHREADOBSERVER
ThreadObserver()
: mHasPendingEvents(false)
, mMonitor("DOMStorageThreadMonitor")
{
}
bool HasPendingEvents() {
mMonitor.AssertCurrentThreadOwns();
return mHasPendingEvents;
}
void ClearPendingEvents() {
mMonitor.AssertCurrentThreadOwns();
mHasPendingEvents = false;
}
Monitor& GetMonitor() { return mMonitor; }
private:
virtual ~ThreadObserver() {}
bool mHasPendingEvents;
// The monitor we drive the thread with
Monitor mMonitor;
};
public:
DOMStorageDBThread();
virtual ~DOMStorageDBThread() {}
virtual nsresult Init();
virtual nsresult Shutdown();
virtual void AsyncPreload(DOMStorageCacheBridge* aCache, bool aPriority = false)
{ InsertDBOp(new DBOperation(aPriority ? DBOperation::opPreloadUrgent : DBOperation::opPreload, aCache)); }
virtual void SyncPreload(DOMStorageCacheBridge* aCache, bool aForce = false);
virtual void AsyncGetUsage(DOMStorageUsageBridge * aUsage)
{ InsertDBOp(new DBOperation(DBOperation::opGetUsage, aUsage)); }
virtual nsresult AsyncAddItem(DOMStorageCacheBridge* aCache, const nsAString& aKey, const nsAString& aValue)
{ return InsertDBOp(new DBOperation(DBOperation::opAddItem, aCache, aKey, aValue)); }
virtual nsresult AsyncUpdateItem(DOMStorageCacheBridge* aCache, const nsAString& aKey, const nsAString& aValue)
{ return InsertDBOp(new DBOperation(DBOperation::opUpdateItem, aCache, aKey, aValue)); }
virtual nsresult AsyncRemoveItem(DOMStorageCacheBridge* aCache, const nsAString& aKey)
{ return InsertDBOp(new DBOperation(DBOperation::opRemoveItem, aCache, aKey)); }
virtual nsresult AsyncClear(DOMStorageCacheBridge* aCache)
{ return InsertDBOp(new DBOperation(DBOperation::opClear, aCache)); }
virtual void AsyncClearAll()
{ InsertDBOp(new DBOperation(DBOperation::opClearAll)); }
virtual void AsyncClearMatchingScope(const nsACString& aScope)
{ InsertDBOp(new DBOperation(DBOperation::opClearMatchingScope, aScope)); }
virtual void AsyncFlush();
virtual bool ShouldPreloadScope(const nsACString& aScope);
virtual void GetScopesHavingData(InfallibleTArray<nsCString>* aScopes);
private:
nsCOMPtr<nsIFile> mDatabaseFile;
PRThread* mThread;
// Used to observe runnables dispatched to our thread and to monitor it.
nsRefPtr<ThreadObserver> mThreadObserver;
// Flag to stop, protected by the monitor returned by
// mThreadObserver->GetMonitor().
bool mStopIOThread;
// Whether WAL is enabled
bool mWALModeEnabled;
// Whether DB has already been open, avoid races between main thread reads
// and pending DB init in the background I/O thread
bool mDBReady;
// State of the database initiation
nsresult mStatus;
// List of scopes having data, for optimization purposes only
nsTHashtable<nsCStringHashKey> mScopesHavingData;
StatementCache mWorkerStatements;
StatementCache mReaderStatements;
// Connection used by the worker thread for all read and write ops
nsCOMPtr<mozIStorageConnection> mWorkerConnection;
// Connection used only on the main thread for sync read operations
nsCOMPtr<mozIStorageConnection> mReaderConnection;
// Time the first pending operation has been added to the pending operations
// list
PRIntervalTime mDirtyEpoch;
// Flag to force immediate flush of all pending operations
bool mFlushImmediately;
// List of preloading operations, in chronological or priority order.
// Executed prioritly over pending update operations.
nsTArray<DBOperation*> mPreloads;
// Collector of pending update operations
PendingOperations mPendingTasks;
// Counter of calls for thread priority rising.
int32_t mPriorityCounter;
// Helper to direct an operation to one of the arrays above;
// also checks IsScopeClearPending for preloads
nsresult InsertDBOp(DBOperation* aOperation);
// Opens the database, first thing we do after start of the thread.
nsresult OpenDatabaseConnection();
nsresult InitDatabase();
nsresult ShutdownDatabase();
// Tries to establish WAL mode
nsresult SetJournalMode(bool aIsWal);
nsresult TryJournalMode();
// Sets the threshold for auto-checkpointing the WAL.
nsresult ConfigureWALBehavior();
void SetHigherPriority();
void SetDefaultPriority();
// Ensures we flush pending tasks in some reasonble time
void ScheduleFlush();
// Called when flush of pending tasks is being executed
void UnscheduleFlush();
// This method is used for two purposes:
// 1. as a value passed to monitor.Wait() method
// 2. as in indicator that flush has to be performed
//
// Return:
// - PR_INTERVAL_NO_TIMEOUT when no pending tasks are scheduled
// - larger then zero when tasks have been scheduled, but it is
// still not time to perform the flush ; it is actual interval
// time to wait until the flush has to happen
// - 0 when it is time to do the flush
PRIntervalTime TimeUntilFlush();
// Notifies to the main thread that flush has completed
void NotifyFlushCompletion();
// Thread loop
static void ThreadFunc(void* aArg);
void ThreadFunc();
};
} // ::dom
} // ::mozilla
#endif /* DOMStorageDBThread_h___ */