Question

我尝试使用Djinni为Android和iOS实现共享的业务逻辑。我不断收到返回自定义记录的方法的错误。我使用以下IDL定义和实现。

audio_book.djinni

audio_book = record {
    id: i32;
    title: string;
}

audio_book_service = interface +c {
    static create(): audio_book_service;
    fetch_audio_book(id: i32): audio_book;
}

生成了以下文件：

audio_book.hpp

#pragma once

#include <cstdint>
#include <string>
#include <utility>

struct AudioBook final {
    int32_t id;
    std::string title;

    AudioBook(int32_t id_,
              std::string title_)
    : id(std::move(id_))
    , title(std::move(title_))
    {}
};

audio_book_service.hpp

#pragma once

#include <cstdint>
#include <memory>

struct AudioBook;

class AudioBookService {
public:
    virtual ~AudioBookService() {}

    static std::shared_ptr<AudioBookService> create();

    virtual AudioBook fetch_audio_book(int32_t id) = 0;
};

我的实施方式

：

audio_book_service_impl.h

#pragma once

#include <iostream>

#include "audio_book_service.hpp"
#include "audio_book.hpp"

class AudioBookServiceImpl : public AudioBookService {

public:
   AudioBook fetch_audio_book(int32_t id) override ;
};

audio_book_service_impl.cpp

#include "audio_book_service_impl.h"

std::shared_ptr<AudioBookService> AudioBookService::create() {
    return std::make_shared<AudioBookServiceImpl>();
}

AudioBook AudioBookServiceImpl::fetch_audio_book(int32_t id) {
    AudioBook audioBook(1, "TEST");
    return audioBook;
}

当我尝试将其编译为Android项目时，它将引发此错误：

app/src/djinni/generated/jni/NativeAudioBookService.cpp:38: error: undefined reference to 'djinni_generated::NativeAudioBook::fromCpp(_JNIEnv*, lynen::AudioBook const&)'
  clang++: error: linker command failed with exit code 1 (use -v to see invocation)
  ninja: build stopped: subcommand failed.

为什么ist说它是未定义的？对于本机类型，它可以毫无问题地进行编译。有没有人有示例返回djinni中的自定义记录或遇到相同的问题？

Answer 1

缺少的功能应该已经生成到NativeAudioBook.cpp中。确保您已将该文件包含在构建规则中。

Answer 2

我忘记了包含生成的.hpp文件。我的CMakeLists.txt仅包含生成的cpp文件，但不包含任何hpp标头。由于Djinni只为定义的常量生成cpp。至于接口和记录djinni，则生成hpp文件。

这是我的CMakeLists.txt解决的问题：

cmake_minimum_required(VERSION 3.4.1)

set(support_dir src/djinni/support-lib/jni)

set(include_dirs src/djinni/generated/cpp/ src/djinni/generated/jni/ src/main/cpp/)

file(
    GLOB_RECURSE support_srcs
    ${support_dir}/*.cpp)

file(
    GLOB_RECURSE lib_srcs
    src/djinni/generated/cpp/*.cpp
    src/djinni/generated/cpp/*.hpp // forgot to include. This fixed the issue.
    src/djinni/generated/jni/*.cpp
    src/main/cpp/*.cpp)

set(complete_src ${support_srcs} ${lib_srcs})

add_library(lynen-shared SHARED ${complete_src})

target_include_directories(
    lynen-shared
    PUBLIC
    ${include_dirs}
    ${support_dir})

感谢@ atwyman，@ mkk的提示。

C ++ Djinni返回记录。未定义对djinni_genic的引用

2 个答案: