Convert references to FileSystem & Co. into shared pointers (avoid use after free)

Also simplified the JsEngine constructor signature while at it.

[Felix Dahlke, 2013-04-18 13:30:12]

http://codereview.adblockplus.org/10310030/diff/1/src/JsEngine.cpp
File src/JsEngine.cpp (right):

http://codereview.adblockplus.org/10310030/diff/1/src/JsEngine.cpp#newcode138
src/JsEngine.cpp:138: fileSystem.reset(new DefaultFileSystem());
I'd rather have this in the constructor and make the getter const. But we should
throw an exception here if it's null.

Likewise for WebRequest and ErrorCallback below.

[Wladimir Palant, 2013-04-18 13:59:55]

http://codereview.adblockplus.org/10310030/diff/1/src/JsEngine.cpp
File src/JsEngine.cpp (right):

http://codereview.adblockplus.org/10310030/diff/1/src/JsEngine.cpp#newcode138
src/JsEngine.cpp:138: fileSystem.reset(new DefaultFileSystem());
On 2013/04/18 13:30:12, Felix H. Dahlke wrote:
> I'd rather have this in the constructor and make the getter const.

The reason for not doing it in the constructor was to avoid creating unnecessary
objects that will be replaced immediately. Are you sure you want this?

> But we should
> throw an exception here if it's null.

I would rather throw an exception in SetFileSystem() - how else can we get an
empty pointer?

[Felix Dahlke, 2013-04-18 14:03:49]

LGTM

[Felix Dahlke, 2013-04-18 14:04:12]

LGTM

http://codereview.adblockplus.org/10310030/diff/1/src/JsEngine.cpp
File src/JsEngine.cpp (right):

http://codereview.adblockplus.org/10310030/diff/1/src/JsEngine.cpp#newcode138
src/JsEngine.cpp:138: fileSystem.reset(new DefaultFileSystem());
On 2013/04/18 13:59:55, Wladimir Palant wrote:
> On 2013/04/18 13:30:12, Felix H. Dahlke wrote:
> > I'd rather have this in the constructor and make the getter const.
> 
> The reason for not doing it in the constructor was to avoid creating
unnecessary
> objects that will be replaced immediately. Are you sure you want this?
> 
> > But we should
> > throw an exception here if it's null.
> 
> I would rather throw an exception in SetFileSystem() - how else can we get an
> empty pointer?

Oh right, was still thinking we pass them in to the constructor. Throwing an
exception in the setters sounds good.

[Wladimir Palant, 2013-04-18 14:42:42]

Added the exceptions in
https://hg.adblockplus.org/libadblockplus/rev/3cb09772d10d