Changes per discussion with Anton

Changes per discussion with Anton
- Add a new API call Dart_StringTolatin1 so that the contents of a
  string object that satisfies Dart_IsStringLatin1 can be gotten
- Tweak Dart_MakeExternalString to copy out the contents of the string
  for valid string objects that can not be externalized by the VM
  (e.g strings in the VM isolate)
Committed: https://code.google.com/p/dart/source/detail?r=16149

[cshapiro, 2012-12-14 00:00:36]

lgtm with comments

I really dislike the nomenclature and documentation and I think it is in the
best interest of our users to change that.  That aside, the functionality does
seem like what we want.

https://chromiumcodereview.appspot.com/11580003/diff/5001/include/dart_api.h
File include/dart_api.h (right):

https://chromiumcodereview.appspot.com/11580003/diff/5001/include/dart_api.h#...
include/dart_api.h:1466: * Gets the Latin-1 (ISO-8859-1) encoded representation
of a string.
This seems misleading, I would really like to see something change.

This API gets the contents of a OneByteString a.k.a. a Latin-1 string.  The
naming philosophy was to have To be reserved for conversions and this is not a
conversion, it will generate an error if the input cannot be encoded as Latin-1.

(Consider Dart_StringToUTF8 below.)

[antonm, 2012-12-14 01:31:59]

Thanks a lot, Siva.

https://chromiumcodereview.appspot.com/11580003/diff/5001/include/dart_api.h
File include/dart_api.h (right):

https://chromiumcodereview.appspot.com/11580003/diff/5001/include/dart_api.h#...
include/dart_api.h:1471: *   until the next call to Dart_ExitScope.
there are two flavours of string data fetching: Dart_StringToUTF16 which allows
caller to pass the buffer caller is managing and Dart_String~ToUTF8 where VM
allocates the buffer.

From my experience, _StringToUTF16 is by far more convenient as it least in my
case I need to copy those data away immediately anyway and hence I save on one
copy.

[siva, 2012-12-14 03:30:09]

addressed comments and changed the API to pass in uint8_t* instead of allocating
the buffer inside.

https://chromiumcodereview.appspot.com/11580003/diff/5001/include/dart_api.h
File include/dart_api.h (right):

https://chromiumcodereview.appspot.com/11580003/diff/5001/include/dart_api.h#...
include/dart_api.h:1466: * Gets the Latin-1 (ISO-8859-1) encoded representation
of a string.
I have changed the description here to word it to say it is not a conversion but
just a straight extraction of data and strings that are not latin1 strings will
get an error.

On 2012/12/14 00:00:36, cshapiro wrote:
> This seems misleading, I would really like to see something change.
> 
> This API gets the contents of a OneByteString a.k.a. a Latin-1 string.  The
> naming philosophy was to have To be reserved for conversions and this is not a
> conversion, it will generate an error if the input cannot be encoded as
Latin-1.
> 
> (Consider Dart_StringToUTF8 below.)

https://chromiumcodereview.appspot.com/11580003/diff/5001/include/dart_api.h#...
include/dart_api.h:1471: *   until the next call to Dart_ExitScope.
I have changed Dart_StringToLatin1 to use the API similar to Dart_StringToUTF16
which should be more convenient for you.

Will try and change Dart_StringToUTF8 to also follow the same pattern in another
CL.

On 2012/12/14 01:31:59, antonm wrote:
> there are two flavours of string data fetching: Dart_StringToUTF16 which
allows
> caller to pass the buffer caller is managing and Dart_String~ToUTF8 where VM
> allocates the buffer.
> 
> From my experience, _StringToUTF16 is by far more convenient as it least in my
> case I need to copy those data away immediately anyway and hence I save on one
> copy.

[antonm, 2012-12-14 03:31:30]

lgtm

https://chromiumcodereview.appspot.com/11580003/diff/5001/include/dart_api.h
File include/dart_api.h (right):

https://chromiumcodereview.appspot.com/11580003/diff/5001/include/dart_api.h#...
include/dart_api.h:1471: *   until the next call to Dart_ExitScope.
Thanks!

On 2012/12/14 03:30:09, siva wrote:
> I have changed Dart_StringToLatin1 to use the API similar to
Dart_StringToUTF16
> which should be more convenient for you.
> 
> Will try and change Dart_StringToUTF8 to also follow the same pattern in
another
> CL.
> 
> On 2012/12/14 01:31:59, antonm wrote:
> > there are two flavours of string data fetching: Dart_StringToUTF16 which
> allows
> > caller to pass the buffer caller is managing and Dart_String~ToUTF8 where VM
> > allocates the buffer.
> > 
> > From my experience, _StringToUTF16 is by far more convenient as it least in
my
> > case I need to copy those data away immediately anyway and hence I save on
one
> > copy.
>