Convert CFXJSE_Value::ToString to return.

Convert CFXJSE_Value::ToString to return.

ThiS Cl updates CFXJSE_Value::ToString() to return a CFX_ByteString instead
of taking an out parameter. It also adds a ToStringC() and ToWideString()
to hide the common conversions that are done on the string value.

Committed: https://pdfium.googlesource.com/pdfium/+/2f5582f46dce2abfe9d75ea5f885a2ce0a4c10d2

[dsinclair, 2016-06-09 16:30:38]

dsinclair@chromium.org changed reviewers:
+ thestig@chromium.org, tsepez@chromium.org

[dsinclair, 2016-06-09 16:30:38]

PTAL.

https://codereview.chromium.org/2044293004/diff/1/xfa/fxfa/parser/xfa_object_...
File xfa/fxfa/parser/xfa_object_imp.cpp (left):

https://codereview.chromium.org/2044293004/diff/1/xfa/fxfa/parser/xfa_object_...
xfa/fxfa/parser/xfa_object_imp.cpp:1438: CFX_WideString wsUseVal = wsValue,
wsID, wsSOM;
This syntax is bonkers.

[Tom Sepez, 2016-06-09 16:43:56]

https://codereview.chromium.org/2044293004/diff/1/xfa/fxjse/value.h
File xfa/fxjse/value.h (right):

https://codereview.chromium.org/2044293004/diff/1/xfa/fxjse/value.h#newcode184
xfa/fxjse/value.h:184: V8_INLINE CFX_ByteStringC ToStringC() const { return
ToString().AsStringC(); }
Nope. The call to ToString() creates a temporary bytestring that lives up until
the semicolon at the end of this statement.  AsStringC doesn't do any copying,
returning pointers into the temporary's buffers.  So we're returing pointers
into something on the stack that gets destructed and popped.

We'll have to put the calls to ToString().AsStringC() into the callers so that
the temporary result of ToString() lives for the duration of what the caller
intends to do with it.

[Tom Sepez, 2016-06-09 16:47:56]

https://codereview.chromium.org/2044293004/diff/1/xfa/fxjse/value.h
File xfa/fxjse/value.h (right):

https://codereview.chromium.org/2044293004/diff/1/xfa/fxjse/value.h#newcode186
xfa/fxjse/value.h:186: return CFX_WideString::FromUTF8(ToStringC());
Note that ToWideString() will be fine (once we fix its ToStringC usage) because
CFX_WideString() allocs and copies.

[dsinclair, 2016-06-09 17:26:54]

https://codereview.chromium.org/2044293004/diff/1/xfa/fxjse/value.h
File xfa/fxjse/value.h (right):

https://codereview.chromium.org/2044293004/diff/1/xfa/fxjse/value.h#newcode184
xfa/fxjse/value.h:184: V8_INLINE CFX_ByteStringC ToStringC() const { return
ToString().AsStringC(); }
On 2016/06/09 16:43:56, Tom Sepez wrote:
> Nope. The call to ToString() creates a temporary bytestring that lives up
until
> the semicolon at the end of this statement.  AsStringC doesn't do any copying,
> returning pointers into the temporary's buffers.  So we're returing pointers
> into something on the stack that gets destructed and popped.
> 
> We'll have to put the calls to ToString().AsStringC() into the callers so that
> the temporary result of ToString() lives for the duration of what the caller
> intends to do with it.

Done.

[Tom Sepez, 2016-06-09 18:02:16]

lgtm

[dsinclair, 2016-06-09 18:48:04]

The CQ bit was checked by dsinclair@chromium.org

[commit-bot: I haz the power, 2016-06-09 18:48:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2044293004/20001

[commit-bot: I haz the power, 2016-06-09 18:48:25]

Description was changed from

==========
Convert CFXJSE_Value::ToString to return.

ThiS Cl updates CFXJSE_Value::ToString() to return a CFX_ByteString instead
of taking an out parameter. It also adds a ToStringC() and ToWideString()
to hide the common conversions that are done on the string value.
==========

to

==========
Convert CFXJSE_Value::ToString to return.

ThiS Cl updates CFXJSE_Value::ToString() to return a CFX_ByteString instead
of taking an out parameter. It also adds a ToStringC() and ToWideString()
to hide the common conversions that are done on the string value.

Committed:
https://pdfium.googlesource.com/pdfium/+/2f5582f46dce2abfe9d75ea5f885a2ce0a4c...
==========

[commit-bot: I haz the power, 2016-06-09 18:48:26]

Committed patchset #2 (id:20001) as
https://pdfium.googlesource.com/pdfium/+/2f5582f46dce2abfe9d75ea5f885a2ce0a4c...