[webkit-dev] Queries regarding indexed db implementation

Jiyeon Kim jiyeon0402.kim at samsung.com
Thu May 3 02:04:05 PDT 2012

On Thursday, May 03, 2012 at 1:59AM, Alec Flett alecflett at chromium.org wrote:

Hi all.


This is Jiyeon Kim recently joined webkit-dev mailing list.


Welcome - I'm somewhat new here myself, but I am working on IndexedDB support in WebKit..



I’ve got two questions on IndexedDB.

First, I wonder, while Web storage and Web SQL have tracker, why Indexed DB doesn’t have tracker.


What do you mean by "tracker" ?

è  Thank you for your reply.  I mean that when you refer to StorageTracker.cpp(for local storage)file and DatabaseTracker.cpp(for web sql) file, they have “tracker” for each functions.

So I would like to know why indexed database doesn’t have tracker.


Second, if you look at IDBFactory::open() method in IDBFactory.cpp file,

the fifth argument of m_backend->open(name, request.get(), context->securityOrigin(), frame, String()); is not about path information but a string (i.e., document->page()->group().groupSettings()->indexedDBDatabasePath();).

I also wonder why it is a string rather than a path.

The m_backend is an interface to the actual database implementation - that tends to deal with stuff at a slightly lower level (i.e. actual paths on disk, etc) - are you looking for a url path? All the IDB's for a security origin are accessable to each other, and not connected to the rest of the URL (i.e.  <http://foo.com/abc> http://foo.com/abc has the same security origin as  <http://foo.com/xyz> http://foo.com/xyz so they have access to the same set of IDB files, so indexedDBDatabasePath() is the same)

è  As you know, refer to IDBLevelDBBackingStore::open method  in IDBLevelDBBackingStore.cpp file, level DB will be opened in memory when “pathBase” is empty. 

è  If we open the level DB in the memory, its data might be lost when browser or other web application finishes using the level DB. The data persistency is not guaranteed in sys reboot. So I’d like to know why fifth argument is null string rather than a path.



Thanks for your time to look into my questions.

Best regards,
Jiyeon Kim


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