The Tor Browser: storage/src/mozStorageConnection.h@b8a032363ba2 (annotated)

storage/src/mozStorageConnection.h@b8a032363ba2 (annotated)

storage/src/mozStorageConnection.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
  * 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 mozilla_storage_Connection_h
 #define mozilla_storage_Connection_h
 #include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "mozilla/Mutex.h"
 #include "nsProxyRelease.h"
 #include "nsThreadUtils.h"
 #include "nsIInterfaceRequestor.h"
 #include "nsDataHashtable.h"
 #include "mozIStorageProgressHandler.h"
 #include "SQLiteMutex.h"
 #include "mozIStorageConnection.h"
 #include "mozStorageService.h"
 #include "mozIStorageAsyncConnection.h"
 #include "mozIStorageCompletionCallback.h"
 #include "nsIMutableArray.h"
 #include "mozilla/Attributes.h"
 #include "sqlite3.h"
 struct PRLock;
 class nsIFile;
 class nsIFileURL;
 class nsIEventTarget;
 class nsIThread;
 namespace mozilla {
 namespace storage {
 class Connection MOZ_FINAL : public mozIStorageConnection
                            , public nsIInterfaceRequestor
 {
 public:
   NS_DECL_THREADSAFE_ISUPPORTS
   NS_DECL_MOZISTORAGEASYNCCONNECTION
   NS_DECL_MOZISTORAGECONNECTION
   NS_DECL_NSIINTERFACEREQUESTOR
   /**
    * Structure used to describe user functions on the database connection.
    */
   struct FunctionInfo {
     enum FunctionType {
       SIMPLE,
       AGGREGATE
     };
     nsCOMPtr<nsISupports> function;
     FunctionType type;
     int32_t numArgs;
   };
   /**
    * @param aService
    *        Pointer to the storage service.  Held onto for the lifetime of the
    *        connection.
    * @param aFlags
    *        The flags to pass to sqlite3_open_v2.
    * @param aAsyncOnly
    *        If |true|, the Connection only implements asynchronous interface:
    *        - |mozIStorageAsyncConnection|;
    *        If |false|, the result also implements synchronous interface:
    *        - |mozIStorageConnection|.
    */
   Connection(Service *aService, int aFlags, bool aAsyncOnly);
   /**
    * Creates the connection to an in-memory database.
    */
   nsresult initialize();
   /**
    * Creates the connection to the database.
    *
    * @param aDatabaseFile
    *        The nsIFile of the location of the database to open, or create if it
    *        does not exist.
    */
   nsresult initialize(nsIFile *aDatabaseFile);
   /**
    * Creates the connection to the database.
    *
    * @param aFileURL
    *        The nsIFileURL of the location of the database to open, or create if it
    *        does not exist.
    */
   nsresult initialize(nsIFileURL *aFileURL);
   /**
    * Fetches runtime status information for this connection.
    *
    * @param aStatusOption One of the SQLITE_DBSTATUS options defined at
    *        http://www.sqlite.org/c3ref/c_dbstatus_options.html
    * @param [optional] aMaxValue if provided, will be set to the highest
    *        istantaneous value.
    * @return the current value for the specified option.
    */
   int32_t getSqliteRuntimeStatus(int32_t aStatusOption,
                                  int32_t* aMaxValue=nullptr);
   /**
    * Registers/unregisters a commit hook callback.
    *
    * @param aCallbackFn a callback function to be invoked on transactions
    *        commit.  Pass nullptr to unregister the current callback.
    * @param [optional] aData if provided, will be passed to the callback.
    * @see http://sqlite.org/c3ref/commit_hook.html
    */
   void setCommitHook(int (*aCallbackFn)(void *) , void *aData=nullptr) {
     MOZ_ASSERT(mDBConn, "A connection must exist at this point");
     ::sqlite3_commit_hook(mDBConn, aCallbackFn, aData);
   };
   /**
    * Lazily creates and returns a background execution thread.  In the future,
    * the thread may be re-claimed if left idle, so you should call this
    * method just before you dispatch and not save the reference.
    *
    * @returns an event target suitable for asynchronous statement execution.
    */
   nsIEventTarget *getAsyncExecutionTarget();
   /**
    * Mutex used by asynchronous statements to protect state.  The mutex is
    * declared on the connection object because there is no contention between
    * asynchronous statements (they are serialized on mAsyncExecutionThread).
    * Currently protects:
    *  - Connection.mAsyncExecutionThreadShuttingDown
    *  - Connection.mAsyncExecutionThread
    *  - Connection.mConnectionClosed
    *  - AsyncExecuteStatements.mCancelRequested
    */
   Mutex sharedAsyncExecutionMutex;
   /**
    * Wraps the mutex that SQLite gives us from sqlite3_db_mutex.  This is public
    * because we already expose the sqlite3* native connection and proper
    * operation of the deadlock detector requires everyone to use the same single
    * SQLiteMutex instance for correctness.
    */
   SQLiteMutex sharedDBMutex;
   /**
    * References the thread this database was opened on.  This MUST be thread it is
    * closed on.
    */
   const nsCOMPtr<nsIThread> threadOpenedOn;
   /**
    * Closes the SQLite database, and warns about any non-finalized statements.
    */
   nsresult internalClose(sqlite3 *aDBConn);
   /**
    * Obtains the filename of the connection.  Useful for logging.
    */
   nsCString getFilename();
   /**
    * Creates an sqlite3 prepared statement object from an SQL string.
    *
    * @param aNativeConnection
    *        The underlying Sqlite connection to prepare the statement with.
    * @param aSQL
    *        The SQL statement string to compile.
    * @param _stmt
    *        New sqlite3_stmt object.
    * @return the result from sqlite3_prepare_v2.
    */
   int prepareStatement(sqlite3* aNativeConnection,
                        const nsCString &aSQL, sqlite3_stmt **_stmt);
   /**
    * Performs a sqlite3_step on aStatement, while properly handling SQLITE_LOCKED
    * when not on the main thread by waiting until we are notified.
    *
    * @param aNativeConnection
    *        The underlying Sqlite connection to step the statement with.
    * @param aStatement
    *        A pointer to a sqlite3_stmt object.
    * @return the result from sqlite3_step.
    */
   int stepStatement(sqlite3* aNativeConnection, sqlite3_stmt* aStatement);
   /**
    * Raw connection transaction management.
    *
    * @see BeginTransactionAs, CommitTransaction, RollbackTransaction.
    */
   nsresult beginTransactionInternal(sqlite3 *aNativeConnection,
                                     int32_t aTransactionType=TRANSACTION_DEFERRED);
   nsresult commitTransactionInternal(sqlite3 *aNativeConnection);
   nsresult rollbackTransactionInternal(sqlite3 *aNativeConnection);
   bool connectionReady();
   /**
    * True if this connection is shutting down but not yet closed.
    */
   bool isClosing();
   /**
    * True if the underlying connection is closed.
    * Any sqlite resources may be lost when this returns true, so nothing should
    * try to use them.
    */
   bool isClosed();
   nsresult initializeClone(Connection *aClone, bool aReadOnly);
 private:
   ~Connection();
   nsresult initializeInternal(nsIFile *aDatabaseFile);
   /**
    * Sets the database into a closed state so no further actions can be
    * performed.
    *
    * @note mDBConn is set to nullptr in this method.
    */
   nsresult setClosedState();
   /**
    * Helper for calls to sqlite3_exec. Reports long delays to Telemetry.
    *
    * @param aNativeConnection
    *        The underlying Sqlite connection to execute the query with.
    * @param aSqlString
    *        SQL string to execute
    * @return the result from sqlite3_exec.
    */
   int executeSql(sqlite3 *aNativeConnection, const char *aSqlString);
   /**
    * Describes a certain primitive type in the database.
    *
    * Possible Values Are:
    *  INDEX - To check for the existence of an index
    *  TABLE - To check for the existence of a table
    */
   enum DatabaseElementType {
     INDEX,
     TABLE
   };
   /**
    * Determines if the specified primitive exists.
    *
    * @param aElementType
    *        The type of element to check the existence of
    * @param aElementName
    *        The name of the element to check for
    * @returns true if element exists, false otherwise
    */
   nsresult databaseElementExists(enum DatabaseElementType aElementType,
                                  const nsACString& aElementName,
                                  bool *_exists);
   bool findFunctionByInstance(nsISupports *aInstance);
   static int sProgressHelper(void *aArg);
   // Generic progress handler
   // Dispatch call to registered progress handler,
   // if there is one. Do nothing in other cases.
   int progressHandler();
   sqlite3 *mDBConn;
   nsCOMPtr<nsIFileURL> mFileURL;
   nsCOMPtr<nsIFile> mDatabaseFile;
   /**
    * Lazily created thread for asynchronous statement execution.  Consumers
    * should use getAsyncExecutionTarget rather than directly accessing this
    * field.
    */
   nsCOMPtr<nsIThread> mAsyncExecutionThread;
   /**
    * Set to true by Close() or AsyncClose() prior to shutdown.
    *
    * If false, we guarantee both that the underlying sqlite3 database
    * connection is still open and that getAsyncExecutionTarget() can
    * return a thread. Once true, either the sqlite3 database
    * connection is being shutdown or it has been
    * shutdown. Additionally, once true, getAsyncExecutionTarget()
    * returns null.
    *
    * This variable should be accessed while holding the
    * sharedAsyncExecutionMutex.
    */
   bool mAsyncExecutionThreadShuttingDown;
   /**
    * Set to true just prior to calling sqlite3_close on the
    * connection.
    *
    * This variable should be accessed while holding the
    * sharedAsyncExecutionMutex.
    */
   bool mConnectionClosed;
   /**
    * Tracks if we have a transaction in progress or not.  Access protected by
    * sharedDBMutex.
    */
   bool mTransactionInProgress;
   /**
    * Stores the mapping of a given function by name to its instance.  Access is
    * protected by sharedDBMutex.
    */
   nsDataHashtable<nsCStringHashKey, FunctionInfo> mFunctions;
   /**
    * Stores the registered progress handler for the database connection.  Access
    * is protected by sharedDBMutex.
    */
   nsCOMPtr<mozIStorageProgressHandler> mProgressHandler;
   /**
    * Stores the flags we passed to sqlite3_open_v2.
    */
   const int mFlags;
   // This is here for two reasons: 1) It's used to make sure that the
   // connections do not outlive the service.  2) Our custom collating functions
   // call its localeCompareStrings() method.
   nsRefPtr<Service> mStorageService;
   /**
    * If |false|, this instance supports synchronous operations
    * and it can be cast to |mozIStorageConnection|.
    */
   const bool mAsyncOnly;
 };
 /**
  * A Runnable designed to call a mozIStorageCompletionCallback on
  * the appropriate thread.
  */
 class CallbackComplete MOZ_FINAL : public nsRunnable
 {
 public:
   /**
    * @param aValue The result to pass to the callback. It must
    *               already be owned by the main thread.
    * @param aCallback The callback. It must already be owned by the
    *                  main thread.
    */
   CallbackComplete(nsresult aStatus,
                    nsISupports* aValue,
                    already_AddRefed<mozIStorageCompletionCallback> aCallback)
     : mStatus(aStatus)
     , mValue(aValue)
     , mCallback(aCallback)
   {
   }
   NS_IMETHOD Run() {
     MOZ_ASSERT(NS_IsMainThread());
     nsresult rv = mCallback->Complete(mStatus, mValue);
     // Ensure that we release on the main thread
     mValue = nullptr;
     mCallback = nullptr;
     return rv;
   }
 private:
   nsresult mStatus;
   nsCOMPtr<nsISupports> mValue;
   // This is a nsRefPtr<T> and not a nsCOMPtr<T> because
   // nsCOMP<T> would cause an off-main thread QI, which
   // is not a good idea (and crashes XPConnect).
   nsRefPtr<mozIStorageCompletionCallback> mCallback;
 };
 } // namespace storage
 } // namespace mozilla
 #endif // mozilla_storage_Connection_h

The Tor Browser / annotate

storage/src/mozStorageConnection.h@b8a032363ba2 (annotated)

storage/src/mozStorageConnection.h