Shorten the path length to get under MAX_PATH on windows.

Shorten the path length to get under MAX_PATH on windows.

Some of the nested directories in each partition have variable length path names. Prepending our isolated storage path structure used to take us over the to MAX_PATH for chrome-extension:// origins when creating the database files for subsystems like Local Storage.

With this change, on XP, assuming a 10-character user name, the Local Storage database file representing the chrome-extension: origin in the Default profile for user "abcdefghij" has this path:

 C:\Documents and Settings\abcedfghij\Local Settings\Application Data\
 Google\Chrome SxS\User Data\Default\Storage\
 ext\bdlahefabekefwlefaancobndodocndn\def\Local Storage\
 chrome-extension_bdlahefabekefwlefaancobndodocndn_0.localstorage-journal

which is 241 characters. This gives 19 characters of headroom from the 260 MAX_PATH.

Previously, when we used "Storage Partitions", "extensions", and "default" instead of "Storage, "ext", and "def", the same database file would have a path length of 263 characters.

This change doesn't completely solve the problem.  If Local Storage is used on a super-long domain, we can still exceed MAX_PATH.  However, using my own profile as an example, of 342 domains, none created paths longer than those of the chrome-extensions so this should be a pretty solid mitigation.

BUG=151450
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=158136

[awong, 2012-09-21 01:07:07]

Charlie: this should be a pretty straightforward review.  If it looks okay,
could you please CQ it for me? :D

[awong, 2012-09-21 03:35:36]

Actually, I'm CQing so there's some chance for this to bake.  Charlie, let me
know if you want me to change anything.

[commit-bot: I haz the power, 2012-09-21 03:36:33]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ajwong@chromium.org/10967030/1

[Charlie Reis, 2012-09-21 16:38:45]

The change LGTM, but the CL description is confusing.

The example you give is missing "ext\", so it should actually be 241 characters.
 And it's not clear that this is the fixed state, after your CL.  Currently,
that path would be 263 characters (over the limit):

C:\Documents and Settings\<username>\Local Settings\Application
Data\Google\Chrome SxS\User Data\Default\Storage
Partitions\extensions\bdlahefabekefwlefaancobndodocndn\default\Local
Storage\chrome-extension_bdlahefabekefwlefaancobndodocndn_0.localstorage-journal

[awong, 2012-09-21 23:27:05]

Ooops..you're right about the miscount to be 241 characters.

Though where are you getting 263?

-Albert


On Fri, Sep 21, 2012 at 9:38 AM, <creis@chromium.org> wrote:

> The change LGTM, but the CL description is confusing.
>
> The example you give is missing "ext\", so it should actually be 241
> characters.
>  And it's not clear that this is the fixed state, after your CL.
>  Currently,
> that path would be 263 characters (over the limit):
>
>
> C:\Documents and Settings\<username>\Local Settings\Application
> Data\Google\Chrome SxS\User Data\Default\Storage
> Partitions\extensions\**bdlahefabekefwlefaancobndodocn**dn\default\Local
> Storage\chrome-extension_**bdlahefabekefwlefaancobndodocn**
> dn_0.localstorage-journal
>
>
https://codereview.chromium.**org/10967030/<https://codereview.chromium.org/1...
>

[Charlie Reis, 2012-09-21 23:40:11]

263 is length of the path before this CL, when it was still "Storage
Partitions", "extensions", and "default":
C:\Documents and Settings\<username>\Local Settings\Application
Data\Google\Chrome SxS\User Data\Default\Storage
Partitions\extensions\bdlahefabekefwlefaancobndodocndn\default\Local
Storage\chrome-extension_bdlahefabekefwlefaancobndodocndn_0.localstorage-journal

The way your description phrases it, it sounds like this CL fixes the
"dangerously close" problem, when really it goes from "already over the limit"
down to "dangerously close to the limit".  Am I correct?

Charlie


On 2012/09/21 23:27:05, awong wrote:
> Ooops..you're right about the miscount to be 241 characters.
> 
> Though where are you getting 263?
> 
> -Albert
> 
> 
> On Fri, Sep 21, 2012 at 9:38 AM, <mailto:creis@chromium.org> wrote:
> 
> > The change LGTM, but the CL description is confusing.
> >
> > The example you give is missing "ext\", so it should actually be 241
> > characters.
> >  And it's not clear that this is the fixed state, after your CL.
> >  Currently,
> > that path would be 263 characters (over the limit):
> >
> >
> > C:\Documents and Settings\<username>\Local Settings\Application
> > Data\Google\Chrome SxS\User Data\Default\Storage
> > Partitions\extensions\**bdlahefabekefwlefaancobndodocn**dn\default\Local
> > Storage\chrome-extension_**bdlahefabekefwlefaancobndodocn**
> > dn_0.localstorage-journal
> >
> >
>
https://codereview.chromium.**org/10967030/%3Chttps://codereview.chromium.org...>
> >

[awong, 2012-09-21 23:50:14]

Ah, I see what you're saying.  I reworded the description. Let me know what you
think.

On 2012/09/21 23:40:11, creis wrote:
> 263 is length of the path before this CL, when it was still "Storage
> Partitions", "extensions", and "default":
> C:\Documents and Settings\<username>\Local Settings\Application
> Data\Google\Chrome SxS\User Data\Default\Storage
> Partitions\extensions\bdlahefabekefwlefaancobndodocndn\default\Local
>
Storage\chrome-extension_bdlahefabekefwlefaancobndodocndn_0.localstorage-journal
> 
> The way your description phrases it, it sounds like this CL fixes the
> "dangerously close" problem, when really it goes from "already over the limit"
> down to "dangerously close to the limit".  Am I correct?
> 
> Charlie
> 
> 
> On 2012/09/21 23:27:05, awong wrote:
> > Ooops..you're right about the miscount to be 241 characters.
> > 
> > Though where are you getting 263?
> > 
> > -Albert
> > 
> > 
> > On Fri, Sep 21, 2012 at 9:38 AM, <mailto:creis@chromium.org> wrote:
> > 
> > > The change LGTM, but the CL description is confusing.
> > >
> > > The example you give is missing "ext\", so it should actually be 241
> > > characters.
> > >  And it's not clear that this is the fixed state, after your CL.
> > >  Currently,
> > > that path would be 263 characters (over the limit):
> > >
> > >
> > > C:\Documents and Settings\<username>\Local Settings\Application
> > > Data\Google\Chrome SxS\User Data\Default\Storage
> > > Partitions\extensions\**bdlahefabekefwlefaancobndodocn**dn\default\Local
> > > Storage\chrome-extension_**bdlahefabekefwlefaancobndodocn**
> > > dn_0.localstorage-journal
> > >
> > >
> >
>
https://codereview.chromium.**org/10967030/%253Chttps://codereview.chromium.o...>
> > >

[Charlie Reis, 2012-09-22 00:18:05]

On 2012/09/21 23:50:14, awong wrote:
> Ah, I see what you're saying.  I reworded the description. Let me know what
you
> think.
> 
> On 2012/09/21 23:40:11, creis wrote:
> > 263 is length of the path before this CL, when it was still "Storage
> > Partitions", "extensions", and "default":
> > C:\Documents and Settings\<username>\Local Settings\Application
> > Data\Google\Chrome SxS\User Data\Default\Storage
> > Partitions\extensions\bdlahefabekefwlefaancobndodocndn\default\Local
> >
>
Storage\chrome-extension_bdlahefabekefwlefaancobndodocndn_0.localstorage-journal
> > 
> > The way your description phrases it, it sounds like this CL fixes the
> > "dangerously close" problem, when really it goes from "already over the
limit"
> > down to "dangerously close to the limit".  Am I correct?
> > 
> > Charlie
> > 
> > 
> > On 2012/09/21 23:27:05, awong wrote:
> > > Ooops..you're right about the miscount to be 241 characters.
> > > 
> > > Though where are you getting 263?
> > > 
> > > -Albert
> > > 
> > > 
> > > On Fri, Sep 21, 2012 at 9:38 AM, <mailto:creis@chromium.org> wrote:
> > > 
> > > > The change LGTM, but the CL description is confusing.
> > > >
> > > > The example you give is missing "ext\", so it should actually be 241
> > > > characters.
> > > >  And it's not clear that this is the fixed state, after your CL.
> > > >  Currently,
> > > > that path would be 263 characters (over the limit):
> > > >
> > > >
> > > > C:\Documents and Settings\<username>\Local Settings\Application
> > > > Data\Google\Chrome SxS\User Data\Default\Storage
> > > > Partitions\extensions\**bdlahefabekefwlefaancobndodocn**dn\default\Local
> > > > Storage\chrome-extension_**bdlahefabekefwlefaancobndodocn**
> > > > dn_0.localstorage-journal
> > > >
> > > >
> > >
> >
>
https://codereview.chromium.**org/10967030/%25253Chttps://codereview.chromium...>
> > > >

Thanks, LGTM.