747409 - Cannot launch multiple different native applications - All apps launched re-launch the 1st app launched

Status: VERIFIED FIXED

(Firefox Graveyard :: Web Apps, defect)

Description

[Jason Smith [:jsmith]]

Steps:

1. Go to https://apps.mozillalabs.com/appdir/
2. Install 2 different applications
3. Launch each application from the desktop shortcut

Expected:

Each application should start-up separately and be different. For example, if I installed BarFight and Dave's Galaxy, launching both of them should start BarFight and Dave's Galaxy in separate windows.

Actual:

Launching any application after launching the first application will re-launch the 1st application. For example, if I launch BarFight, the BarFight application starts up. If I then launch Dave's Galaxy, another BarFight application starts up.

Comment 1

[Tim Abraldes [:TimAbraldes] [:tabraldes]]

After the stub calls XRE_main, code is hit that checks whether an instance of the app is already running.  On Windows, it checks for previous instances of the app by looking for a specifically-named window.

This is where the name of the window is built:
  https://mxr.mozilla.org/mozilla-central/source/toolkit/xre/nsNativeAppSupportWin.cpp#494

Note that the name of the window searched is "gAppData->name" + "MessageWindow".  The app data for our apps used to contain the name of the app, but now every app has the value "Webapp Runtime" as its "gAppData->name" value.

Comment 2

[Tim Abraldes [:TimAbraldes] [:tabraldes]]

Attachment: Patch v1 - Sets the name of the app in the gAppData structure

The attached patch fixes the issue in my local testing.  However, this won't work if two apps happen to have the same name.  Additionally, this patch doesn't check that the name contains only ASCII characters, which is a requirement according to this comment: https://mxr.mozilla.org/mozilla-central/source/xpcom/build/nsXREAppData.h?rev=a771e4924188#76

To fix the first issue, we could consider using the profile instead of the app name.  These are guaranteed to be unique (the profile dir is the same as the app's install dir).  I'm not yet sure how to approach the second issue.

Comment 3

[Tim Abraldes [:TimAbraldes] [:tabraldes]]

Attachment: Patch v2 - Set the "name" field of the nsXREAppData to the name of the profile dir (equivalent to the name of the webapp's install dir)

This patch sets the "name" of the nsXREAppData struct to be the name of the profile dir of the webapp (which is also the install dir of the app).

No two webapps will have the same value for this.  Also, this value is based on scheme (always ASCII?), port (always ASCII since it's a number), and domain (which, if we're not already, we will soon be using the ASCII version of).

One outstanding issue: What happens when the profile dir has a name that is really long?  The code that checks for existing windows uses this function, which uses a buffer of size 128 for the app name: https://mxr.mozilla.org/mozilla-central/source/toolkit/xre/nsNativeAppSupportWin.cpp?rev=e1bef8037d36#494

Comment 4

[Myk Melez [:myk] [@mykmelez]]

Comment on attachment 617153 [details] [diff] [review]
Patch v2 - Set the "name" field of the nsXREAppData to the name of the profile dir (equivalent to the name of the webapp's install dir)

(In reply to Tim Abraldes from comment #3)
> This patch sets the "name" of the nsXREAppData struct to be the name of the
> profile dir of the webapp (which is also the install dir of the app).

This seems like a reasonable enough solution, although I'm worried about unintended side-effects.  But in any case it's an improvement over the current situation.  r=myk


> One outstanding issue: What happens when the profile dir has a name that is
> really long?  The code that checks for existing windows uses this function,
> which uses a buffer of size 128 for the app name:
> https://mxr.mozilla.org/mozilla-central/source/toolkit/xre/
> nsNativeAppSupportWin.cpp?rev=e1bef8037d36#494

The DNS spec limits domain names to 255 characters.  Given the schemes we accept (just http and https?) and the maximum size of a port number (5), we can determine the largest possible size of one of these identifying strings.  So we could update nsNativeAppSupportWin to use a large enough buffer.  But I'd want feedback from a toolkit peer on that change.

Comment 5

[Tim Abraldes [:TimAbraldes] [:tabraldes]]

Comment on attachment 617153 [details] [diff] [review]
Patch v2 - Set the "name" field of the nsXREAppData to the name of the profile dir (equivalent to the name of the webapp's install dir)

https://hg.mozilla.org/integration/mozilla-inbound/rev/4c1aa39b85a9

Comment 6

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/4c1aa39b85a9