[mojo] Support native types with mojom wire format

[mojo] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1524613002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=569669
TBR=yzshen@chromium.org

Committed: https://crrev.com/770743799f563212a30682ec1a3d464cb7a89eae
Cr-Commit-Position: refs/heads/master@{#365998}

[Ken Rockot(use gerrit already), 2015-12-14 07:17:47]

Description was changed from

==========
[mojo] Support native types with mojom wire format

BUG=
==========

to

==========
[mojo,WIP] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1524613002
  2. https://codereview.chromium.org/1515423002
  3. https://codereview.chromium.org/1517043004
  4. https://codereview.chromium.org/1524693002
  5. https://codereview.chromium.org/1520153002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=
==========

[Ken Rockot(use gerrit already), 2015-12-14 18:46:58]

Description was changed from

==========
[mojo,WIP] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1524613002
  2. https://codereview.chromium.org/1515423002
  3. https://codereview.chromium.org/1517043004
  4. https://codereview.chromium.org/1524693002
  5. https://codereview.chromium.org/1520153002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=
==========

to

==========
[mojo,WIP] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1526533002
  6. This CL

BUG=
==========

[Ken Rockot(use gerrit already), 2015-12-14 20:20:00]

Description was changed from

==========
[mojo,WIP] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1526533002
  6. This CL

BUG=
==========

to

==========
[mojo,WIP] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1524613002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=
==========

[Ken Rockot(use gerrit already), 2015-12-14 21:09:08]

Description was changed from

==========
[mojo,WIP] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1524613002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=
==========

to

==========
[mojo,WIP] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1524613002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=569669
==========

[Ken Rockot(use gerrit already), 2015-12-15 03:06:12]

Description was changed from

==========
[mojo,WIP] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1524613002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=569669
==========

to

==========
[mojo] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1524613002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=569669
==========

[Ken Rockot(use gerrit already), 2015-12-16 01:39:23]

rockot@chromium.org changed reviewers:
+ yzshen@chromium.org

[Ken Rockot(use gerrit already), 2015-12-16 01:39:24]

Here's a really basic starting point for serializing mojom-defined structs from
native type traits. It only handles POD fields at the moment, and I'm not crazy
about the naming of things.

WDYT about the general approach? Namely:

 - bindings expecting to find a Foo_Traits<T> specific to mojom type Foo (as
opposed to a generic StructTraits<Foo, T>. 
 - generating a Foo_Reader interface as opposed to a generic mojo::Reader<T>
which would just have to be specialized for each type anyway

[Ken Rockot(use gerrit already), 2015-12-18 02:06:08]

Description was changed from

==========
[mojo] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1524613002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=569669
==========

to

==========
[mojo] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1524613002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=569669
TBR=yzshen@chromium.org
==========

[Ken Rockot(use gerrit already), 2015-12-18 02:50:14]

TBRing yzshen based on our offline discussion before he went OOO. This shouldn't
have any effect on existing Mojo users (other than generating some extra dead
code), and it would be nice to land some version of it to see how well it works
in practice.

[Ken Rockot(use gerrit already), 2015-12-18 02:50:26]

The CQ bit was checked by rockot@chromium.org

[commit-bot: I haz the power, 2015-12-18 02:50:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1524703002/200001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1524703002/200001

[commit-bot: I haz the power, 2015-12-18 03:00:23]

Committed patchset #11 (id:200001)

[commit-bot: I haz the power, 2015-12-18 03:01:54]

Description was changed from

==========
[mojo] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1524613002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=569669
TBR=yzshen@chromium.org
==========

to

==========
[mojo] Support native types with mojom wire format

Add support for defining custom serialization routines to go between
arbitrary C++ types and mojom struct types with no extra copying
and no manual buffer management.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1524613002
  6. https://codereview.chromium.org/1526533002
  7. This CL

BUG=569669
TBR=yzshen@chromium.org

Committed: https://crrev.com/770743799f563212a30682ec1a3d464cb7a89eae
Cr-Commit-Position: refs/heads/master@{#365998}
==========

[commit-bot: I haz the power, 2015-12-18 03:01:54]

Patchset 11 (id:??) landed as
https://crrev.com/770743799f563212a30682ec1a3d464cb7a89eae
Cr-Commit-Position: refs/heads/master@{#365998}

[Jeffrey Yasskin, 2016-01-28 18:01:40]

jyasskin@chromium.org changed reviewers:
+ jyasskin@chromium.org

[Jeffrey Yasskin, 2016-01-28 18:01:40]

Thanks!

https://codereview.chromium.org/1524703002/diff/200001/mojo/public/cpp/bindin...
File mojo/public/cpp/bindings/struct_traits.h (right):

https://codereview.chromium.org/1524703002/diff/200001/mojo/public/cpp/bindin...
mojo/public/cpp/bindings/struct_traits.h:25: //        static bool
Read(MojomType::Reader r, T* out);
Could you document whether a 'true' or 'false' return is a failure?

Also, is there documentation for the API of the Reader type? (I haven't looked
yet, so sorry if it's obvious.)

And, what's a "serializable form"?

[Ken Rockot(use gerrit already), 2016-01-28 20:35:26]

On 2016/01/28 at 18:01:40, jyasskin wrote:
> Thanks!
> 
>
https://codereview.chromium.org/1524703002/diff/200001/mojo/public/cpp/bindin...
> File mojo/public/cpp/bindings/struct_traits.h (right):
> 
>
https://codereview.chromium.org/1524703002/diff/200001/mojo/public/cpp/bindin...
> mojo/public/cpp/bindings/struct_traits.h:25: //        static bool
Read(MojomType::Reader r, T* out);
> Could you document whether a 'true' or 'false' return is a failure?
> 
> Also, is there documentation for the API of the Reader type? (I haven't looked
yet, so sorry if it's obvious.)
> 

No, no documentation yet, and there should be :)

> And, what's a "serializable form"?

A "serializable form" is any type which is understood by the bindings layer as
the given field's mojom definition.
Currently since only POD and struct fields are supported, a serializable form of
a field of type T is a value
that is either of type T, implicitly convertible to T, or a type U for which
there exists a definition of
mojo::StructTraits<T, U>.

[Ken Rockot(use gerrit already), 2016-01-28 20:37:10]

On 2016/01/28 at 20:35:26, Ken Rockot wrote:
> On 2016/01/28 at 18:01:40, jyasskin wrote:
> > Thanks!
> > 
> >
https://codereview.chromium.org/1524703002/diff/200001/mojo/public/cpp/bindin...
> > File mojo/public/cpp/bindings/struct_traits.h (right):
> > 
> >
https://codereview.chromium.org/1524703002/diff/200001/mojo/public/cpp/bindin...
> > mojo/public/cpp/bindings/struct_traits.h:25: //        static bool
Read(MojomType::Reader r, T* out);
> > Could you document whether a 'true' or 'false' return is a failure?
> > 
> > Also, is there documentation for the API of the Reader type? (I haven't
looked yet, so sorry if it's obvious.)
> > 
> 
> No, no documentation yet, and there should be :)
> 
> > And, what's a "serializable form"?
> 
> A "serializable form" is any type which is understood by the bindings layer as
the given field's mojom definition.

Err, that should read "understood by the bindings layer to be convertible to the
field's mojom-defined type"

> Currently since only POD and struct fields are supported, a serializable form
of a field of type T is a value
> that is either of type T, implicitly convertible to T, or a type U for which
there exists a definition of
> mojo::StructTraits<T, U>.

[Ken Rockot(use gerrit already), 2016-01-28 20:39:36]

On 2016/01/28 at 20:37:10, Ken Rockot wrote:
> On 2016/01/28 at 20:35:26, Ken Rockot wrote:
> > On 2016/01/28 at 18:01:40, jyasskin wrote:
> > > Thanks!
> > > 
> > >
https://codereview.chromium.org/1524703002/diff/200001/mojo/public/cpp/bindin...
> > > File mojo/public/cpp/bindings/struct_traits.h (right):
> > > 
> > >
https://codereview.chromium.org/1524703002/diff/200001/mojo/public/cpp/bindin...
> > > mojo/public/cpp/bindings/struct_traits.h:25: //        static bool
Read(MojomType::Reader r, T* out);
> > > Could you document whether a 'true' or 'false' return is a failure?
> > > 
> > > Also, is there documentation for the API of the Reader type? (I haven't
looked yet, so sorry if it's obvious.)
> > > 
> > 
> > No, no documentation yet, and there should be :)
> > 
> > > And, what's a "serializable form"?
> > 
> > A "serializable form" is any type which is understood by the bindings layer
as the given field's mojom definition.
> 
> Err, that should read "understood by the bindings layer to be convertible to
the field's mojom-defined type"
> 
> > Currently since only POD and struct fields are supported, a serializable
form of a field of type T is a value
> > that is either of type T, implicitly convertible to T, or a type U for which
there exists a definition of
> > mojo::StructTraits<T, U>.

And one more addendum... in the near future there should be adapters so that
things like std::vector<T> can be
implicitly viewed as a mojo::Array<T> or mojo::Array<U> when
mojo::StructTraits<U, T> is defined; so a StructTraits
field accessor could return a const ref to a std::vector and the bindings layer
can copy data from it directly
into a message buffer.