hi Kenton Varda * when I do this:* kj::ArrayPtr<const kj::ArrayPtr<const capnp::word>> segments = message. getSegmentsForOutput();
the segments size Always 1，so in protobuf I use bytes field to send the segments[0].asChars(); *Is there any problem in using it like this* 在 2019年10月8日星期二 UTC+8上午12:31:10，Kenton Varda写道： > > messageToFlatArray() involves an extra copy compared to > getSegmentsForOutput(). > > However, you are putting the bytes into a protobuf anyway. Protobuf will > make many copies. So I don't think you should worry too much about this one > extra copy. > > If you really want to use getSegmentsForOutput(), then you need to use a > `repeated bytes` field in protobuf and you need to add each segment to the > repeated bytes. > > -Kenton > > On Sun, Oct 6, 2019 at 8:00 PM 张小 <[email protected] <javascript:>> wrote: > >> hi Kenton： >> getSegmentsForOutput() performance better than messageToFlatArray >> right? These two interfaces What scenarios are applied to? >> >> best wish >> whutbd >> >> 在 2019年10月7日星期一 UTC+8上午3:41:23，Kenton Varda写道： >>> >>> Your code only handles the case of a single segment. I recommend using >>> the methods in capnp/serialize.h and org.capnproto.Serialize. I do not >>> recommend using getSegmentsForOutput() nor constructing a MessageReader >>> directly from a segment array, as these are advanced functions that can >>> more easily go wrong. >>> >>> That said, in your example case, only a single segment should be needed, >>> so something else is wrong too. >>> >>> I don't see any other obvious problems with the code you provided. I >>> suspect a bug exists in the code you didn't show. I recommend you try to >>> verify that the bytes on the receiving end are actually exactly the bytes >>> from the sending end. Try logging the byte values and the size of the >>> segment at each end to make sure everything matches. >>> >>> I think the most likely problem is that somewhere your `char*` is being >>> interpreted as a NUL-terminated string, and is therefore being truncated at >>> the first zero-valued byte. Most likely, the very first byte in the segment >>> is a zero, so probably your ByteBuffer on the Java end ends up being >>> zero-length. This probably leads to the struct appearing to contain only >>> default values, hence goodsId is 0. >>> >>> -Kenton >>> >>> On Sat, Oct 5, 2019 at 11:28 PM 张小 <[email protected]> wrote: >>> >>>> hi Kenton： >>>> I need your help,This problem has been bothering me for many days. >>>> >>>> In c++ server ,code like this >>>> capnp::MallocMessageBuilder message; >>>> FullInfo::Builder fullInfo = message.initRoot<FullInfo>(); >>>> fullInfo.setGoodsId(919731) >>>> >>>> kj::ArrayPtr<const kj::ArrayPtr<const capnp::word>> segments >>>> = message.getSegmentsForOutput(); >>>> kj::ArrayPtr<const capnp::word> segment = segments[0]; >>>> kj::ArrayPtr<const char> chars = segment.asChars(); >>>> const char* mem_buf = chars.begin(); >>>> int32_t mem_buf_len = chars.size(); >>>> >>>> and c++ server send the mem_buf to java_client by rpc call(bytes field) >>>> >>>> *Client and server communicate through protobuf rpc* >>>> >>>> In java_client code like this:() >>>> >>>> com.google.protobuf.ByteString capn_object_bytes = >>>> response.getCapnObject(); >>>> ByteBuffer[] bytes_buffer = new ByteBuffer[1]; >>>> bytes_buffer[0] = capn_object_bytes.asReadOnlyByteBuffer(); >>>> MessageReader message = new MessageReader(bytes_buffer, >>>> ReaderOptions.DEFAULT_READER_OPTIONS); >>>> Display.FullInfo.Reader fullInfo = >>>> message.getRoot(Display.FullInfo.factory); >>>> System.out.println("goodsId:" + fullInfo.getGoodsId()); >>>> >>>> but in java_client ，print goodsId is 0, however in c++ server, I >>>> setGoodsId(919731) ,What's wrong with my method of use? @Kenton >>>> >>>> the fullinfo.capnp code is: >>>> @0xcb70f505c89d1634; >>>> >>>> using Java = import "./compiler/src/main/schema/capnp/java.capnp"; >>>> $Java.package("org.capnproto.examples"); >>>> $Java.outerClassname("Display"); >>>> >>>> struct FullInfo{ >>>> goodsId @1 :Int64; >>>> } >>>> >>>> >>>> >>>> >>>> >>>> 在 2019年10月1日星期二 UTC+8上午3:23:37，Kenton Varda写道： >>>>> >>>>> Are you transmitting one big buffer containing all the segments, or >>>>> are you transmitting each segment separately? >>>>> >>>>> It looks like you're trying to do the latter, but in that case you >>>>> cannot use Serialize.read() to read it. You need to use `new >>>>> MessageReader(segments)`. >>>>> >>>>> -Kenton >>>>> >>>>> On Mon, Sep 30, 2019 at 5:52 AM 张小 <[email protected]> wrote: >>>>> >>>>>> First Time: >>>>>> In C++ server,I Use capnp::DynamicStruct, code like this: >>>>>> capnp::MallocMessageBuilder msg; >>>>>> capnp::DynamicStruct::Builder fullinfo_builder >>>>>> = msg.initRoot<capnp::DynamicStruct>(g_schema); >>>>>> capnp::DynamicStruct::Builder fullInfo = >>>>>> msg.initRoot<capnp::DynamicStruct>(g_schema); >>>>>> >>>>>> capnp::messageToFlatArray(msg); ---->convert it to char* send to >>>>>> java_cliet >>>>>> >>>>>> Java Client ,code like this: >>>>>> MessageReader message >>>>>> = >>>>>> org.capnproto.Serialize.read(capn_object_bytes.asReadOnlyByteBuffer());, >>>>>> Info.Reader adInfo = message.getRoot(Info.factory); >>>>>> >>>>>> Above ， My First Time do work , but The Second Time, I do like this >>>>>> ,it do not work: >>>>>> In C++ server, code like this: >>>>>> >>>>>> capnp::MallocMessageBuilder message; >>>>>> Info::Builder info = message.initRoot<Info>(); >>>>>> info.setId(123); >>>>>> kj::ArrayPtr<const kj::ArrayPtr<const capnp::word>> segments = >>>>>> message.getSegmentsForOutput(); >>>>>> >>>>>> then I convert the segments object to char* send to java_client by >>>>>> proto rpc_call (bytes field) >>>>>> >>>>>> >>>>>> Java Client ,code like this: >>>>>> MessageReader message >>>>>> = >>>>>> org.capnproto.Serialize.read(capn_object_bytes.asReadOnlyByteBuffer());, >>>>>> Info.Reader adInfo = message.getRoot(Info.factory); >>>>>> >>>>>> >>>>>> In Second Time, happen Error like this: >>>>>> >>>>>> Exception in thread "main" java.lang.IllegalArgumentException >>>>>> at java.nio.Buffer.limit(Buffer.java:275) >>>>>> at org.capnproto.Serialize.read(Serialize.java:140) >>>>>> at org.capnproto.Serialize.read(Serialize.java:111) >>>>>> >>>>>> How Can I do , In Second Time ,thanks >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> 在 2019年9月30日星期一 UTC+8下午8:29:41，David Renshaw写道： >>>>>>> >>>>>>> On the Java side, you need to first read the bytes into a >>>>>>> `MessageReader`. That's typically done via one of the >>>>>>> `Serialize.read()` >>>>>>> methods. >>>>>>> >>>>>>> The `AnyPointer.Reader()` is not intended for external use. Probably >>>>>>> we should make it private. >>>>>>> >>>>>>> >>>>>>> On Mon, Sep 30, 2019 at 6:25 AM 张小 <[email protected]> wrote: >>>>>>> >>>>>>>> C++ server send Capn Object to JavaClient like this >>>>>>>> >>>>>>>> capnp::MallocMessageBuilder message; >>>>>>>> Info::Builder info = message.initRoot<Info>(); >>>>>>>> info.setId(123); >>>>>>>> kj::ArrayPtr<const kj::ArrayPtr<const capnp::word>> segments = >>>>>>>> message.getSegmentsForOutput(); >>>>>>>> >>>>>>>> then I convert the segments object to char* send to java_client >>>>>>>> by proto rpc_call (bytes field) >>>>>>>> >>>>>>>> >>>>>>>> Then In java_client, I do like this to read the capn object >>>>>>>> com.google.protobuf.ByteString capn_object_bytes = >>>>>>>> response.getCapnObject() >>>>>>>> SegmentReader segment = new >>>>>>>> SegmentReader(capn_object_bytes.asReadOnlyByteBuffer(), null); >>>>>>>> AnyPointer.Reader any = new AnyPointer.Reader(segment, 0, >>>>>>>> 64*1024*1024); >>>>>>>> Info.Reader info = any.getAs(Info.factory); >>>>>>>> System.out.println("Id:" + info.getId()); >>>>>>>> >>>>>>>> >>>>>>>> run java_cliet ,happend error like this : >>>>>>>> Exception in thread "main" java.lang.NullPointerException >>>>>>>> at org.capnproto.WireHelpers.readStructPointer(WireHelpers.java:918) >>>>>>>> at >>>>>>>> org.capnproto.StructFactory.fromPointerReaderRefDefault(StructFactory.java:34) >>>>>>>> at >>>>>>>> org.capnproto.StructFactory.fromPointerReader(StructFactory.java:41) >>>>>>>> at >>>>>>>> org.capnproto.StructFactory.fromPointerReader(StructFactory.java:24) >>>>>>>> at org.capnproto.AnyPointer$Reader.getAs(AnyPointer.java:56) >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "Cap'n Proto" group. >>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>> send an email to [email protected]. >>>>>>>> To view this discussion on the web visit >>>>>>>> https://groups.google.com/d/msgid/capnproto/081ab20b-5eae-43d5-a4fc-8230ef39d4a5%40googlegroups.com >>>>>>>> >>>>>>>> <https://groups.google.com/d/msgid/capnproto/081ab20b-5eae-43d5-a4fc-8230ef39d4a5%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>>>> . >>>>>>>> >>>>>>> -- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "Cap'n Proto" group. >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>> send an email to [email protected]. >>>>>> To view this discussion on the web visit >>>>>> https://groups.google.com/d/msgid/capnproto/816c3227-c2b2-4b72-8ead-e707759a257c%40googlegroups.com >>>>>> >>>>>> <https://groups.google.com/d/msgid/capnproto/816c3227-c2b2-4b72-8ead-e707759a257c%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>> . >>>>>> >>>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Cap'n Proto" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/capnproto/1e177ff5-e49f-4d4a-b5f3-1c096604bb29%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/capnproto/1e177ff5-e49f-4d4a-b5f3-1c096604bb29%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "Cap'n Proto" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/capnproto/222eed4a-8f6a-48e7-828e-09235b228253%40googlegroups.com >> >> <https://groups.google.com/d/msgid/capnproto/222eed4a-8f6a-48e7-828e-09235b228253%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "Cap'n Proto" group. 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