8 Commits

Author SHA1 Message Date
Damien Neil
97e7f57dbb reflect/protoreflect: replace Mutable with NewMessage
Remove the Mutable methods from KnownFields, List, and Map, replacing
them with methods which return a new, empty message value without adding
that value to the collection.

The new API is simpler, since it clearly applies only to message values,
and more orthogonal, since it provides a way to create a value without
mutating the collection. This latter point is particularly useful in
map deserialization, where the key may be unknown at the time the value
is deserialized.

Drop the Mutable interface, since it is no longer necessary.

Change-Id: Ic5f3d06a2aa331a5d5cd2b4e670a3dba4a74f77c
Reviewed-on: https://go-review.googlesource.com/c/153278
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
2018-12-10 21:17:16 +00:00
Joe Tsai
9667c4816d cmd/protoc-gen-go: reduce technical debt
The following TODOs were addressed:
* Consistently collect all enums, messages, and extensions in a breadth-first order.
The practical affect of this is that the declaration order in a Go file may change.
This simplifies reflection generation, which relies on consistent ordering.
* Removal of placeholder declarations (e.g., "var _ = proto.Marshal") since
protogen is intelligent about including imports as necessary.
* Always generate a default variable or constant for explicit empty strings.
The practical effect of this is the addition of new declarations in some cases.
However, it simplifies our logic such that it matches the protobuf data model.
* Generate the registration statements in a consistent order.

Change-Id: I627bb72589432bb65d53b50965ea88e5f7983977
Reviewed-on: https://go-review.googlesource.com/c/152778
Reviewed-by: Damien Neil <dneil@google.com>
2018-12-07 03:13:48 +00:00
Joe Tsai
b6405bd782 cmd/protoc-gen-go: add support for protobuf reflection
Implement support in protoc-gen-go for generating messages and enums
that satisfy the v2 protobuf reflection interfaces. Specifically, the following
are added:
* top-level variable representing the file descriptor
* ProtoReflect method on enums (to implement protoV2.Enum)
* ProtoReflect method on messages (to implement protoV2.Message)

The following are not supported yet:
* resolving transitive dependencies for file imports
* Extension descriptors
* Service descriptors

The implementation approach creates a single array for all the message and enum
declarations and references sections of that array to complete dependencies.
Since protobuf declarations can form a graph (a message may depend on itself),
it is difficult to construct a graph as a single literal. One way is to use
placeholder descriptors, but that is not efficient as it requires encoding
the full name of each dependent enum and message and then later resolving it;
thus, both expanding the binary size and also increasing initialization cost.
Instead, we add a prototype.{Enum,Message}.Reference method to obtain a
descriptor reference for the purposes for satisfying dependencies.
As such, nested declarations and dependencies are populated in an init function.

Other changes to support the implementation:
* Added a protoimpl package to expose the MessageType type and also the
MessageTypeOf and EnumTypeOf helper functions.
* Added a protogen.File.GoIdent field to provide a suggested variable name
for the file descriptor.
* Added prototype.{Enum,Message}.Reference that provides a descriptor reference
for the purposes for satisfying cyclic dependencies.
* Added protoreflect.{Syntax,Cardinality,Kind}.GoString to obtain a Go source
identifier that represents the given constant.

Change-Id: I9455764882dee6ad10f251901e7d419091e8bf1d
Reviewed-on: https://go-review.googlesource.com/c/150074
Reviewed-by: Damien Neil <dneil@google.com>
2018-12-05 19:32:12 +00:00
Joe Tsai
d7e97bc71b cmd/protoc-gen-go: generate XXX_OneofWrappers instead of XXX_OneofFuncs
The marshaler, unmarshaler, and sizer functions are unused ever since
the underlying implementation was switched to be table-driven.
Change the function to only return the wrapper structs.

This change:
* enables generated protos to drop dependencies on certain proto types
* reduces the size of generated protos
* simplifies the implementation of oneofs in protoc-gen-go

Updates #708

Change-Id: I845c9009bc0236d1b51d34b014dc3e184303c0f2
Reviewed-on: https://go-review.googlesource.com/c/151357
Reviewed-by: Damien Neil <dneil@google.com>
2018-11-27 19:36:27 +00:00
Damien Neil
44000a1bea cmd/protoc-gen-go: treat extensions fields as proto2 in some places
The v1 generator doesn't include a "proto3" tag on extension fields,
even when the field is defined in a proto3 file. Match that behavior for
consistency. We can probably change this later if we want to; it's
unlikely anyone is depending on this behavior.

The v1 generator uses pointer types for extension fields, even when the
field is defined in a proto3 file. (e.g., *FooEnum instead of FooEnum.)
Match this behavior. We can't change this without breaking compatibility
in the generated code.

Change-Id: I4072f3dd1c915bf9ab89f1d5198e0144cb4de20f
Reviewed-on: https://go-review.googlesource.com/c/144282
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
2018-10-24 19:46:45 +00:00
Damien Neil
154da98aa5 cmd/protoc-gen-go: special cases for MessageSet extensions
Add special-case handling for extension fields named
"message_set_extension" that extend a message_set_wire_format message.

Support special cases for a proto1 feature that was superseded by proto2
extensions.

Change-Id: Icbdb711111c66be547bf8d6f37ab3079c320e2a1
Reviewed-on: https://go-review.googlesource.com/136536
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
2018-09-24 17:25:31 +00:00
Joe Tsai
01ab29648e go.mod: rename google.golang.org/proto as github.com/golang/protobuf/v2
This change was created by running:
	git ls-files | xargs sed -i "s|google.golang.org/proto|github.com/golang/protobuf/v2|g"

This change is *not* an endorsement of "github.com/golang/protobuf/v2" as the
final import path when the v2 API is eventually released as stable.
We continue to reserve the right to make breaking changes as we see fit.

This change enables us to host the v2 API on a repository that is go-gettable
(since go.googlesource.com is not a known host by the "go get" tool;
and google.golang.org/proto was just a stub URL that is not currently served).
Thus, we can start work on a forked version of the v1 API that explores
what it would take to implement v1 in terms of v2 in a backwards compatible way.

Change-Id: Ia3ebc41ac4238af62ee140200d3158b53ac9ec48
Reviewed-on: https://go-review.googlesource.com/136736
Reviewed-by: Damien Neil <dneil@google.com>
2018-09-24 16:11:50 +00:00
Damien Neil
a6c374a8f1 cmd/protoc-gen-go: add test data for proto3 extensions
Change-Id: I2d47db2c177553dc2a3dacc66c70db579c1145fd
Reviewed-on: https://go-review.googlesource.com/136535
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
2018-09-20 19:56:44 +00:00