I've got a native library which has a function with the following signature:
int git_remote_download(char **filename, git_remote *remote);
I'm trying to consume it from my managed code like this:
(blindly copied from some other code)
[DllImport(libgit2)]
public static extern int git_remote_download(
[MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof (Utf8Marshaler))] out string filename,
RemoteSafeHandle remote);
As I'm getting an AccessViolationException, looks like I'm doing something wrong. How do I declare it properly?
Related
I want to pass multiple optional objects in function as varags ?
Optional<ab> ab = Optional.of(ab);
Optional<cd> cd = Optional.of(cd);
Optional<dc> dc = Optional.of(dc);
Optional<ba> ba = Optional.of(ba);
data(ab, cd, dc, ba);
data(Optional<Object>... objects){...}
I am getting error if i don this, any suggestion how can be proceed?
It isn’t related to varargs. You can’t pass an Optional<SomeSpecificType> where an Optional<Object> is expected. They are not compatible.
Assume just (without varargs):
static void data(Optional<Object> object) {
// …
}
Now if we try
Optional<String> ab = Optional.of("");
data(ab);
In my Eclipse I get this error message:
The method data(Optional<Object>) in the type MyClass is not
applicable for the arguments (Optional<String>)
Java generics are defined with this restriction. You also cannot pass, for example a List<String> where a List<Object> is expected.
You can overcome the limitation by declaring the method generic too:
static <T> void data(Optional<T> object) {
// …
}
Or just like this:
static void data(Optional<?> object) {
// …
}
With any of these two declarations the call above is OK.
BTW, #HadiJ is correct in the comment: Optional is meant for return values for from methods that may or may not be there. They have very few other good uses, and as parameters is not one of them. It seems to me that for your use case you should just pass the arguments that are there and leave out those that aren’t. The your data method may receive a longer or shorter argument array, but will just have to handle all elements of the array without caring about Optional. And passing String, Integer, LocalDate, etc, to a method declared void data(Object... objs) is straightforward and poses no problem.
Here, or here for a complete version, you can find a sample GRPC "Hello World" project for Unity. Only the first version, that is built for Unity and wrapped in a DLL is working perfectly fine in Unity IDE and on Standalone build. The Raw Grpc.Core files are referencing everything correctly in IDE but they have Marshaling problem.
Unfortunately, it cannot get build for UWP with IL2CPP backend. Unity builds the project and creates a .sln project. But Visual Studio always gives LNK2001 for GRPC properties on the final compilation.
Here are first error codes:
LNK2001 unresolved external _grpccsharp_init#0
LNK2001 unresolved external _grpccsharp_shutdonw#0
LNK2001 unresolved external _grpccsharp_version_string#0
...
Ok, thanks to #Sunius, I digged into it a little bit more. There are some points, I am going to add to the question:
There are two methods regarding referencing extern methods in GRPC C# package. They are named static and shared libs.
internal class DllImportsFromStaticLib
{
private const string ImportName = "__Internal";
[DllImport(ImportName)]
public static extern void grpcsharp_init();
[DllImport(ImportName)]
public static extern void grpcsharp_shutdown();
...
}
and
internal class DllImportsFromSharedLib
{
private const string ImportName = "grpc_csharp_ext";
[DllImport(ImportName)]
public static extern void grpcsharp_init();
[DllImport(ImportName)]
public static extern void grpcsharp_shutdown();
...
}
I tried to test it with the shared one, I got another linking error file which is a little bit different.
LNK2001 unresolved external _dlopen#8
LNK2001 unresolved external _dlsym#8
...
In two separate methods, extern methods are getting connected to the internal interface:
public NativeMethods(DllImportsFromStaticLib unusedInstance)
{
this.grpccsharp_init = DllImportsFromStaticLib.grpccsharp_init;
this.grpccsharp_shutdown = DllImportsFromStaticLib.grpccsharp_shutdonw;
...
}
and
public NativeMethods(DllImportsFromSharedLib unusedInstance)
{
this.grpccsharp_init = DllImportsFromSharedLib.grpccsharp_init;
this.grpccsharp_shutdown = DllImportsFromSharedLib.grpccsharp_shutdonw;
...
}
And which method will get called is defined here:
private static NativMethods LoadNativeMethodsUnity()
{
switch(PlatformApis.GetUnityRuntimePlatform())
{
case "IPhonePlayer":
return new NativeMethods(new NativeMethods.DllImportsFromStaticLib());
default:
return new NativeMethods(new NativeMethods.DllImportsFromSharedLib());
}
}
Some updates:
Thanks to #jsmouret, there is Stub.c file in his Grpc Github with fake methods, so Linker does not complain about Grpc_init methods anymore.
Next Error: dlopen, dlsym, dlerror:
First, I tried to use the same, Stub technique, but it did not help in this case, or maybe I did it wrong.
Thanks to #Sunius, I commented out all of "__Internal" dll import codes. So I am not getting any dlopen, dlsym, and dlerror errors.
Next Error: It happens from inside application, not the visual studio debugger. It tells me: "exception: to marshal a managed method, please add an attribute named 'MonoPInvokeCallback' to the method definition."
exception: error loading the embedded resource "Grpc.Core.roots.pem"
and
exception: To marshal a managed method, please add an attribute named 'MonoPInvokeCallback' to the method definition.
After I googled it, I know my options, but the question it, for which method should I do that?!
Thanks to my colleague Alice, #Sunius and #jsmouret, at the end, grpc works on UWP on Unity Platform through this steps:
Download Grpc.Core folder from Google Grpc Github.
Download Grpc Unity plugin from their official site.
Copy the runtime folder to your Grpc.Core folder. Please remove Grpc.Core.dll that you get from Grpc Unity Plugin, since we are using their source code.
Grpc should be in a folder called, Plugins in Unity, otherwise it will not be recognized.
Include this file in your runtime folder.
Include the Stub also from the Unity Plugin Inspector for WSA.
Find runtime .dll for Windows and include them in WSA from Unity Plugin Inspector.
By now, you should be getting _dlopen error.
Search through your Unity Solution with an IDE for "__Internal". There are not so many places, but comment them out. Also some methods that are depended on "__Internal"s, like dlopen and dlsym.
By now, you are not getting anymore build error but you need to make Grpc work.
Search for something like "DefaultSslRootsOverride" and comment out like below:
internal static class DefaultSslRootsOverride
{
const string RootsPemResourceName = "Grpc.Core.roots.pem";
static object staticLock = new object();
/// <summary>
/// Overrides C core's default roots with roots.pem loaded as embedded resource.
/// </summary>
public static void Override(NativeMethods native)
{
lock (staticLock)
{
//var stream = typeof(DefaultSslRootsOverride).GetTypeInfo().Assembly.GetManifestResourceStream(RootsPemResourceName);
//if (stream == null)
//{
// throw new IOException(string.Format("Error loading the embedded resource \"{0}\"", RootsPemResourceName));
//}
//using (var streamReader = new StreamReader(stream))
//{
// var pemRootCerts = streamReader.ReadToEnd();
// native.grpcsharp_override_default_ssl_roots(pemRootCerts);
//}
}
}
}
Search for something like "static void HandWrite" and add an attribute like something in below:
[MonoPInvokeCallback(typeof(GprLogDelegate))]
private static void HandleWrite(IntPtr fileStringPtr, int line, ulong threadId, IntPtr severityStringPtr, IntPtr msgPtr)
{
try
{
var logger = GrpcEnvironment.Logger;
string severityString = Marshal.PtrToStringAnsi(severityStringPtr);
string message = string.Format("{0} {1}:{2}: {3}",
threadId,
Marshal.PtrToStringAnsi(fileStringPtr),
line,
Marshal.PtrToStringAnsi(msgPtr));
switch (severityString)
{
case "D":
logger.Debug(message);
break;
case "I":
logger.Info(message);
break;
case "E":
logger.Error(message);
break;
default:
// severity not recognized, default to error.
logger.Error(message);
break;
}
}
catch (Exception e)
{
Console.WriteLine("Caught exception in native callback " + e);
}
}
I guess, you are done. In case, it did not work for your UWP, let me know, maybe I can help. :)
It looks like your plugin uses "__Internal" P/Invoke to call those native functions:
https://github.com/grpc/grpc/blob/befc7220cadb963755de86763a04ab6f9dc14200/src/csharp/Grpc.Core/Internal/NativeMethods.Generated.cs#L542
However, the linker cannot locate those functions and thus fails. You should change that code to either specify the DLL file name where the functions are implemented, or drop the source files with definitions for those functions into your Unity project. Or, if that code path isn't actually invoked (since you said it works on the standalone player), #ifdef it out from UWP build.
You can find more information about "__Internal" P/Invoke here:
https://docs.unity3d.com/Manual/windowsstore-plugins-il2cpp.html
I have a protobuf message like this:
message Update {
Path path = 1; // The path (key) for the update.
Value value = 2 [deprecated=true]; // The value (value) for the update.
TypedValue val = 3; // The explicitly typed update value.
}
// TypedValue is used to encode a value being sent between the client and
// target (originated by either entity).
message TypedValue {
oneof value {
string string_val = 1; // String value.
int64 int_val = 2; // Integer
....
google.protobuf.Any any_val = 9; // protobuf.Any encoded bytes.
....
}
}
On the server side (C++), we are setting this field as follows (LLDP is the outer class and Interfaces is inside that):
openconfig_lldp::Lldp out;
GetLldpProto(&out);
update->mutable_val()->mutable_any_val()->PackFrom(out.interfaces());
On the client side (Java), we are extracting this field like this:
OpenconfigLldp.Lldp.Interfaces interfaces = update.getVal().getAnyVal().unpack(OpenconfigLldp.Lldp.Interfaces.class);
This is throwing a InvalidProtocolBufferException exception. When I dump the "update" in my Java client, I see this:
path {
elem {
name: "lldp"
}
elem {
name: "interfaces"
}
}
val {
any_val {
type_url: "type.googleapis.com/openconfig_lldp.Lldp.Interfaces"
value: "\212\207\237\334\v\374\001\022\371\001\262\211\267l\031\342\367\304\260\002\v\n\tEth 1/1/1\242\340\247\230\017\002\b\001\352\316\234\250\017\324\001\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh1\342\253\214\353\001\v\n\tEth 1/1/1\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh2\342\253\214\353\001\v\n\tEth 1/1/2\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh3\342\253\214\353\001\v\n\tEth 1/1/3\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh4\342\253\214\353\001\v\n\tEth 1/1/4\242\364\301\261\a\002\b\n\212\207\237\334\v\374\001\022\371\001\262\211\267l\031\342\367\304\260\002\v\n\tEth 1/1/2\242\340\247\230\017\002\b\001\352\316\234\250\017\324\001\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh1\342\253\214\353\001\v\n\tEth 1/1/1\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh2\342\253\214\353\001\v\n\tEth 1/1/2\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh3\342\253\214\353\001\v\n\tEth 1/1/3\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh4\342\253\214\353\001\v\n\tEth 1/1/4\242\364\301\261\a\002\b\n\212\207\237\334\v\374\001\022\371\001\262\211\267l\031\342\367\304\260\002\v\n\tEth 1/1/3\242\340\247\230\017\002\b\001\352\316\234\250\017\324\001\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh1\342\253\214\353\001\v\n\tEth 1/1/1\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh2\342\253\214\353\001\v\n\tEth 1/1/2\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh3\342\253\214\353\001\v\n\tEth 1/1/3\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh4\342\253\214\353\001\v\n\tEth 1/1/4\242\364\301\261\a\002\b\n\212\207\237\334\v\374\001\022\371\001\262\211\267l\031\342\367\304\260\002\v\n\tEth 1/1/4\242\340\247\230\017\002\b\001\352\316\234\250\017\324\001\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh1\342\253\214\353\001\v\n\tEth 1/1/1\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh2\342\253\214\353\001\v\n\tEth 1/1/2\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh3\342\253\214\353\001\v\n\tEth 1/1/3\242\364\301\261\a\002\b\n\262\217\304\272\017/\022-\302\340\317\247\001\'\202\225\377\302\001\b\n\006Neigh4\342\253\214\353\001\v\n\tEth 1/1/4\242\364\301\261\a\002\b\n"
}
}
The type_url seems correct to me. What am I doing wrong here?
Thanks for your time.
EDIT #1:
I looked at the exception string. It is "Type of the Any message does not match the given class."
The same proto file is used for C++ and Java, but I see "openconfig_lldp.Lldp.Interfaces" in C++, where as, it is "OpenconfigLldp.Lldp.Interfaces" in Java. Need to find out why..
EDIT #2:
The same .proto file is used. In this case, it is:
openconfig_lldp.proto
---------------------
syntax = "proto3";
package openconfig.openconfig_lldp;
message Lldp {
message Config {
....
....
}
....
....
}
In case of Java, I see the parent class as OpenconfigLldp in a package called openconfig_lldp.
package openconfig.openconfig_lldp;
public final class OpenconfigLldp {
private OpenconfigLldp() {}
....
....
/**
* Protobuf type {#code openconfig.openconfig_lldp.Lldp}
*/
public static final class Lldp extends com.google.protobuf.GeneratedMessageV3 implements
// ##protoc_insertion_point(message_implements:openconfig.openconfig_lldp.Lldp)
....
....
}
In C++, I don't see any class called "OpenconfigLldp" generated. Instead it is just "Lldp"
So, the type_url in the Any.protobuf is a mismatch. C++ side puts it as
type_url: "type.googleapis.com/openconfig_lldp.Lldp.Interfaces"
While in the Java side I use:
OpenconfigLldp.Lldp.Interfaces interfaces = update.getVal().getAnyVal().unpack(OpenconfigLldp.Lldp.Interfaces.class);
Anyone has thoughts on why there is a wrapper class in Java protoc output?
EDIT #3
Apparently looks like it is because of the "outer_class_name". In the Java code, I have an outer class "OpenconfigLldp".
The type_url format is:
type.googleapis.com/packagename.messagename
So, C++ code sets this to openconfig_lldp.Lldp.Interfaces.
But, this maps to OpenconfigLldp.Lldp.Interfaces in Java.
How could I work around this?
FINAL EDIT and FINAL QUESTION
After some digging around, this is what I found out.
By default, type_url is:
type_url: "type.googleapis.com/openconfig_lldp.Lldp.Interfaces"
On the Java side, I looked at the Any implementation. It tries to compare this with:
openconfig.openconfig_lldp.Lldp.Interfaces
I found this out by printing:
Lldp.Interfaces defaultInstance = (Lldp.Interfaces)Internal.getDefaultInstance(Lldp.Interfaces.class);
logger.info("full descriptor name: " + defaultInstance.getDescriptorForType().getFullName());
So, I hacked the C++ side to send:
update->mutable_val()->mutable_any_val()->set_type_url(std::string("type.googleapis.com/openconfig.openconfig_lldp.Lldp.Interfaces"));
So, I think I know what is happening here!
Thanks for reading through all the edits.
I am not sure if I understand correctly what's going wrong -- ideally the qualified names would be in protocol buffer namespaces -- language specific mappings shouldn't matter.
If the question is still open, I'd recommend to move the core of it to the top, preserving the edits as "what I have done so far".
Perhaps this is some kind of bug that could be worked around with on of these options:
java_multiple_files
java_outer_classname
More details about these options can be found here:
https://developers.google.com/protocol-buffers/docs/proto3
I have Base and Dervided classes. In the Base class I have a typedef for specific function pointer (I think this is function pointer, im not sure):
typedef void (responseHandler)(BaseClass* instance,int resultCode, char* resultString);
And in the same base class I have several functions which accepts this typedef:
unsigned sendDescribeCommand(responseHandler* responseHandler, Authenticator* authenticator = NULL);
In my custom derived class from this Base class I have my response handler function, like this:
void continueAfterDESCRIBE(RTSPClient* rtspClient, int resultCode, char* resultString);
How I can use this method as input for sendDescribeCommand?
I tried this:
DerivedClass->sendDescribeCommand(DerivedCLass->continueAfterDescribe, MyAuth), but this did not build with error:
"error C3867: 'DerivedClass::continueAfterDESCRIBE': non-standard syntax; use '&' to create a pointer to member"
I also tried to use std::bind:
auto responseCallback = std::bind(&DerivedClass::continueAfterDESCRIBE, DerivedClassInstance);
DerivedClass->sendDescribeCommand(responseCallback, ourAuthenticator);
It also give me an error: no suitable conversion from std::bind to my response handler.
I know there is a way to make my method static, but Im curious if there is another way?
In order to keep some code readable and avoid typos, I'm using the following statement in the public section of a class definition in a header file:
using Assembly_Tuple = std::tuple <std::vector <std::string>, Trigger_Map, Attribute_Map>;
I'm declaring a function in the header file with Assembly_Tuple as a return type:
Assembly_Tuple merge_node_attributes(const std::string& node_name, std::string tmpl_name="");
And I'm defining the function in the source file:
Widget_Server_Interface::Assembly_Tuple
Widget_Server_Interface::merge_node_attributes(const std::string& n, const std::string& t)
{
//...
}
But when I try to compile, I get the following error:
src/WidgetServer/WidgetServerInterface.cpp:31:1: error: ‘Assembly_Tuple’ in ‘class Widget_Server_Interface’ does not name a type
However, inside definitions, there aren't any problems.
If I change that line to the egregious:
std::tuple<std::vector<std::string>, Trigger_Map, std::map<int,Node_Value>>
Widget_Server_Interface::merge_node_attributes (...) {...}
it's fine. Clearly the problem is using the alias outside of scope, even though it's public
and I'm explicitly calling on the class namespace.
I looked in Bjarne's book but he doesn't mention anywhere whether or not this is legal.
This is using gcc 4.7.
Mostly, I would just like to know why this isn't valid.