Yes, just to expand on this - the descriptor protos aren't directly accessible, but the information contained within them is - via the public types in the Google.Protobuf.Reflection namespace.
We're able to do this because we've looked (very carefully!) at how descriptor.proto works in terms of proto3 - basically we generate code *as if* it were proto3 syntax, and have workarounds for couple of issues that throws up. Jon On Friday, 9 October 2015 19:18:42 UTC+1, Feng Xiao wrote: > > On Fri, Oct 9, 2015 at 10:51 AM, Walter Schulze <[email protected] > <javascript:>> wrote: > >> In other words C# and those new languages won't be able to serialize the >> descriptor? >> > descriptor.proto is an exception. It's allowed to be imported by proto3 > files to support custom options. I.e., the following is explicitly allowed: > syntax = "proto3"; > package test; > > *import "google/protobuf/descriptor.proto";* > > *extend google.protobuf.FieldOptions {* > * string my_field_option = 123456789;* > *}* > > message TestMessage { > int32 value = 1 [*(my_field_option) = "Some extra option data"*]; > } > > However, the ability to use these descriptor info at run-time may be > limited (or not present) in certain languages. It depends on what API is > provided by the specific language. +Jon Skeet could probably say more about > how to use/access descriptors in C#. > > > > >> >> On 9 October 2015 at 19:44, 'Feng Xiao' via Protocol Buffers < >> [email protected] <javascript:>> wrote: >> >>> The decision is not to support proto2 in C# (and probably also for all >>> other languages that are new in v3.0.0+). >>> >>> On Fri, Oct 9, 2015 at 10:42 AM, Teddy Zhang <[email protected] >>> <javascript:>> wrote: >>> >>>> Will the C# implementation support proto2 message as well? >>>> What is the compatibility story between proto2 and proto 3? I assume >>>> the wire format is compatible as long as no proto 3 exclusive features >>>> are used. >>>> >>>> >>>> On Tuesday, August 4, 2015 at 5:43:36 AM UTC-7, Jon Skeet wrote: >>>> >>>>> That looks like you're expecting a protobuf.net-style approach - to >>>>> which the answer is "no" and will continue to be "no". >>>>> >>>>> The C# support will continue to be based on generated code, but >>>>> there's a new code generator and runtime now in the master branch. The >>>>> main >>>>> changes from the previous code are: >>>>> >>>>> - proto3-only support (no proto2 at all) >>>>> - mutable generated types rather than the Java-style builders and >>>>> immutable messages >>>>> >>>>> Jon >>>>> >>>>> On Monday, 3 August 2015 22:50:06 UTC+1, The Nguyen Xuan wrote: >>>>>> >>>>>> Does this version support object type in C# ? >>>>>> >>>>>> ex: >>>>>> >>>>>> [ProtoMember(1)] >>>>>> public object A {get;set;} >>>>>> >>>>>> thank. >>>>>> >>>>>> Vào 11:51:01 UTC+7 Thứ Năm, ngày 11 tháng 12 năm 2014, Feng Xiao đã >>>>>> viết: >>>>>>> >>>>>>> Hi all, >>>>>>> >>>>>>> I just published protobuf v3.0.0-alpha-1 on our github site: >>>>>>> https://github.com/google/protobuf/releases/tag/v3.0.0-alpha-1 >>>>>>> >>>>>>> This is the first alpha release of protobuf v3.0.0. In protobuf >>>>>>> v3.0.0, we will add a new protobuf language version (aka proto3) and >>>>>>> support a wider range of programming languages (to name a few: ruby, >>>>>>> php, >>>>>>> node.js, objective-c). This alpha version contains C++ and Java >>>>>>> implementation with partial proto3 support (see below for details). In >>>>>>> future releases we will add support for more programming languages and >>>>>>> implement the full proto3 feature set. Besides proto3, this alpha >>>>>>> version >>>>>>> also includes two other new features: map fields and arena allocation. >>>>>>> They >>>>>>> are implemented for both proto3 and the old protobuf language version >>>>>>> (aka >>>>>>> proto2). >>>>>>> >>>>>>> We are currently working on the documentation of these new features >>>>>>> and when it's ready it will be updated to our protobuf developer >>>>>>> guide <https://developers.google.com/protocol-buffers/docs/overview>. >>>>>>> For the time being if you have any questions regarding proto3 or other >>>>>>> new >>>>>>> features, please post your question in the discussion group. >>>>>>> >>>>>>> CHANGS >>>>>>> ======= >>>>>>> Version 3.0.0-alpha-1 (C++/Java): >>>>>>> >>>>>>> General >>>>>>> * Introduced Protocol Buffers language version 3 (aka proto3). >>>>>>> >>>>>>> When protobuf was initially opensourced it implemented Protocol >>>>>>> Buffers >>>>>>> language version 2 (aka proto2), which is why the version number >>>>>>> started from v2.0.0. From v3.0.0, a new language version >>>>>>> (proto3) is >>>>>>> introduced while the old version (proto2) will continue to be >>>>>>> supported. >>>>>>> >>>>>>> The main intent of introducing proto3 is to clean up protobuf >>>>>>> before >>>>>>> pushing the language as the foundation of Google's new API >>>>>>> platform. >>>>>>> In proto3, the language is simplified, both for ease of use and >>>>>>> to >>>>>>> make it available in a wider range of programming languages. At >>>>>>> the >>>>>>> same time a few features are added to better support common >>>>>>> idioms >>>>>>> found in APIs. >>>>>>> >>>>>>> The following are the main new features in language version 3: >>>>>>> >>>>>>> 1. Removal of field presence logic for primitive value fields, >>>>>>> removal >>>>>>> of required fields, and removal of default values. This >>>>>>> makes proto3 >>>>>>> significantly easier to implement with open struct >>>>>>> representations, >>>>>>> as in languages like Android Java, Objective C, or Go. >>>>>>> 2. Removal of unknown fields. >>>>>>> 3. Removal of extensions, which are instead replaced by a new >>>>>>> standard >>>>>>> type called Any. >>>>>>> 4. Fix semantics for unknown enum values. >>>>>>> 5. Addition of maps. >>>>>>> 6. Addition of a small set of standard types for >>>>>>> representation of time, >>>>>>> dynamic data, etc. >>>>>>> 7. A well-defined encoding in JSON as an alternative to binary >>>>>>> proto >>>>>>> encoding. >>>>>>> >>>>>>> This release (v3.0.0-alpha-1) includes partial proto3 support >>>>>>> for C++ and >>>>>>> Java. Items 6 (well-known types) and 7 (JSON format) in the >>>>>>> above feature >>>>>>> list are not implemented. >>>>>>> >>>>>>> A new notion "syntax" is introduced to specify whether a .proto >>>>>>> file >>>>>>> uses proto2 or proto3: >>>>>>> >>>>>>> // foo.proto >>>>>>> syntax = "proto3"; >>>>>>> message Bar {...} >>>>>>> >>>>>>> If omitted, the protocol compiler will generate a warning and >>>>>>> "proto2" will >>>>>>> be used as the default. This warning will be turned into an >>>>>>> error in a >>>>>>> future release. >>>>>>> >>>>>>> We recommend that new Protocol Buffers users use proto3. >>>>>>> However, we do not >>>>>>> generally recommend that existing users migrate from proto2 from >>>>>>> proto3 due >>>>>>> to API incompatibility, and we will continue to support proto2 >>>>>>> for a long >>>>>>> time. >>>>>>> >>>>>>> * Added support for map fields (implemented in C++/Java for both >>>>>>> proto2 and >>>>>>> proto3). >>>>>>> >>>>>>> Map fields can be declared using the following syntax: >>>>>>> >>>>>>> message Foo { >>>>>>> map<string, string> values = 1; >>>>>>> } >>>>>>> >>>>>>> Data of a map field will be stored in memory as an unordered map >>>>>>> and it >>>>>>> can be accessed through generated accessors. >>>>>>> >>>>>>> C++ >>>>>>> * Added arena allocation support (for both proto2 and proto3). >>>>>>> >>>>>>> Profiling shows memory allocation and deallocation constitutes a >>>>>>> significant >>>>>>> fraction of CPU-time spent in protobuf code and arena allocation >>>>>>> is a >>>>>>> technique introduced to reduce this cost. With arena allocation, >>>>>>> new >>>>>>> objects will be allocated from a large piece of preallocated >>>>>>> memory and >>>>>>> deallocation of these objects is almost free. Early adoption >>>>>>> shows 20% to >>>>>>> 50% improvement in some Google binaries. >>>>>>> >>>>>>> To enable arena support, add the following option to your .proto >>>>>>> file: >>>>>>> >>>>>>> option cc_enable_arenas = true; >>>>>>> >>>>>>> Protocol compiler will generate additional code to make the >>>>>>> generated >>>>>>> message classes work with arenas. This does not change the >>>>>>> existing API >>>>>>> of protobuf messages and does not affect wire format. Your >>>>>>> existing code >>>>>>> should continue to work after adding this option. In the future >>>>>>> we will >>>>>>> make this option enabled by default. >>>>>>> >>>>>>> To actually take advantage of arena allocation, you need to use >>>>>>> the arena >>>>>>> APIs when creating messages. A quick example of using the arena >>>>>>> API: >>>>>>> >>>>>>> { >>>>>>> google::protobuf::Arena arena; >>>>>>> // Allocate a protobuf message in the arena. >>>>>>> MyMessage* message = Arena::CreateMessage<MyMessage>(&arena); >>>>>>> // All submessages will be allocated in the same arena. >>>>>>> if (!message->ParseFromString(data)) { >>>>>>> // Deal with malformed input data. >>>>>>> } >>>>>>> // Must not delete the message here. It will be deleted >>>>>>> automatically >>>>>>> // when the arena is destroyed. >>>>>>> } >>>>>>> >>>>>>> Currently arena does not work with map fields. Enabling arena in >>>>>>> a .proto >>>>>>> file containing map fields will result in compile errors in the >>>>>>> generated >>>>>>> code. This will be addressed in a future release. >>>>>>> ======= >>>>>>> >>>>>>> Thanks, >>>>>>> Feng >>>>>>> >>>>>> >>> -- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "Protocol Buffers" group. >>> To unsubscribe from this topic, visit >>> https://groups.google.com/d/topic/protobuf/ZRpcfmeGK6s/unsubscribe. >>> To unsubscribe from this group and all its topics, send an email to >>> [email protected] <javascript:>. >>> To post to this group, send email to [email protected] >>> <javascript:>. >>> Visit this group at http://groups.google.com/group/protobuf. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> > -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. 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