使用 JNA 和 Ada 的 Interface.C 包将 Ada 动态库与 Java 接口 [英] Interface Ada dynamic Library with Java using JNA and Ada's Interface.C packages
问题描述
我必须写一个 DLL 应该提供一个简单的服务，需要:
I have to write a DLL is supposed to provide a simple service that takes:
- 在字符串或字节数组中(相当于 char*)
- IN 整数，显式 in char* 的大小
- IN 相当于库用于写入数据的 char* 缓冲区
- 用于写入的可用 char* 缓冲区的 IN 大小
- OUT 有效写入大小到 out char* 缓冲区
从 C 的角度来看，签名应该是这样的:
Using a C point of view, the signature should look like:
void myService (char* inBuffer, // as in string
int anInteger, // as in param
char* outBuffer, // used as out buffer, but initalized by calling code
int outBufferSize, // the initaliaed size
int usedBufferSize // used as out param, the actually used size
);
该库被选择在 Ada 中编码有几个原因(几个 Ada 包重复使用，我们不想再次编码，也不想重新设计(遗留)).该库应该在 Java 项目中使用(我们不想从 Java 端重新编码 lib 提供的服务).(这样做的主要原因是该库隐藏了复杂的 Ada 类型转换为 JSON + 一个协议库.)
The library is chosen to be coded in Ada for several reasons (several Ada packages reuse that we do no want to code again nor redesign (legacy)). The library is supposed to be used in a Java project (and we do not want to recode from Java side the services provided by lib). (The main reason for this is that the library hides complex Ada types conversion to JSON + a protocol library.)
该库未来也会与C或C++接口，所以主要思想是依赖于基本类型.
The library shall also be interfaced with C or C++ in the future, so the main idea is to rely on basic types.
如何同时实现与 C 和 Java 的接口?
(我找到了一个解决方案，所以我想在下面分享详细信息；请参阅我自己的答案.由于旧的工作场所网络浏览器有很多错误，因此无法使用复选框进行操作...)
(I found one solution, so I wanted to share the details below ; see my own answer. Couldn't do it using the checkbox due to old workplace webbrowser being very buggy ...)
推荐答案
这里是我如何使用 JNA 和 Ada 的 Interface.C 包设法将 Java 与 Ada 库连接起来.
Here is how I managed to interface Java with an Ada Library using the JNA and Ada's Interface.C packages.
dll 相当简单，这里提供的 Ada 和 Java 代码显示了 char* 作为输入或输出参数的至少 2 种用法.
The dll is rather simple, and the Ada and Java code provided here show at least 2 usages of char* as in or out parameters.
可以阅读以下文档:JNA 文档、这个 Ada wiki，Ada 标准文档 和 其他一些 Ada 标准文档.
One can read the following docs : JNA documentation, this Ada wiki, Ada standard doc and some other Ada standard doc.
注意:请注意，以下 Java 代码适用于任何匹配的 C 接口声明.请参阅帖子结尾处建议的 .h 文件.当然，Java 控制台结果将取决于 DLL 实现.
N.B.: Note that the following Java code would work with any matching C interface declaration. See the proposed .h file at end of post. Of course Java console result would depend on DLL implementation.
您需要在 Java 项目中包含 JNA.jar jar 和 JNA-Platform.jar.请参阅 JNA GitHub 下载.
You'll need to include in your java project the JNA.jar jar and the JNA-Platform.jar.
see JNA GitHub for downloads.
确保使用一致的 Java 和 Ada lib 架构:即 32 位或 64 位.否则，JNA/Java 将无法加载库.
Be sure to use a consistent Java and Ada lib architecture : i.e. both 32 bits or both 64 bits. Otherwise, JNA/Java won't be able to load the library.
不要忘记使用以下 VM 选项 -Djna.debug_load=true 在控制台中查看 JNA 的日志！
Don't also forget to use the following VM option -Djna.debug_load=true to see the JNA's log in console !
您的 Java 项目/bin 文件夹应包含以下内容:
Your Java's project /bin folder shall contain the following:
- 生成的 Ada DLL(使用给定的代码，它将是
libadalib.dll) - 你的
libgnat-version.dll - 您的
libgcc_s_seh-1.dll
请注意，您可能需要在自己的 DLL 附近放置一些 gnat DLL.我目前还没有设法将所有东西都打包到我自己的 DLL 中.
Please note that you may need to put some gnat DLLs near your own one. I currently have not yet managed to pack everything in my own DLL.
因此，您可能需要在生成的 dll 的同一文件夹中具有以下内容(即您的 Java 项目的 /bin 目录):
So you may need to have the following in same folder of the produced dll (I.e. your Java project's /bin directory):
- 你的 libgnat-version.dll
- 你的 libgcc_s_seh-1.dll
如果需要解决这个问题，请使用 DependancyWalker.(参见 http://www.dependencywalker.com/)
Use DependancyWalker if needed to figure this out. (see http://www.dependencywalker.com/)
有一个 GPR 选项来激活/停用自动 DLL 精化，但我还没有测试过.
There is a GPR option to activate / deactivate automatic DLL elaboration, but I do not have tested it yet.
Ada 代码
Ada 库项目:
project adalib is
for Languages use ("Ada");
for Source_Dirs use (project'Project_Dir & "./src");
for Library_Kind use "dynamic"; -- for DLL
for Library_Name use project'Name; -- will produce "libadalib.dll"
for Library_Interface use ("ada_interface");
for Library_Dir use project'Project_Dir & "./dll";
for Library_Src_Dir use project'Project_Dir & "./dll";
-- include other DLL / .a here if needed
-- for Library_Options use ("-L" & path_to_lib,
-- "-l" & path_to_lib
-- );
-- define your favorite compiler, builder, binder, linker options
end adalib;
<小时>
./src ada 文件
./src ada files
ada_interface.ads
ada_interface.ads
pragma Ada_2012;
with Interfaces.C;
with Interfaces.C.Strings;
package ada_interface is
procedure myService (
inBuffer : in Interfaces.C.Strings.chars_ptr; -- as in
anInteger : in Interfaces.C.int;
outBuffer : in Interfaces.C.Strings.chars_ptr; -- as out buffer
outBufferSize : in Interfaces.C.int; -- max out buffer size
usedBufferSize : out Interfaces.C.int
);
pragma Export (Convention => C,
Entity => myService,
External_Name => "Renamed_myService");
end ada_interface;
ada_interface.adb
ada_interface.adb
pragma Ada_2012;
with Ada.Text_IO;
with Interfaces.C.Strings;
package body ada_interface is
procedure myService (
inBuffer : in Interfaces.C.Strings.chars_ptr; -- as in
anInteger : in Interfaces.C.int;
outBuffer : in Interfaces.C.Strings.chars_ptr; -- as out buffer
outBufferSize : in Interfaces.C.int; -- max out buffer size
usedBufferSize : out Interfaces.C.int
)
is
-- if elaboration needs to be explicitly called
procedure ada_elaboration;
pragma import (C, ada_elaboration, "adalibinit"); -- "<name of lib>init". May not be needed with proper options in GPR
Required_Length : Natural := Natural (outBufferSize);
myString : String := "This is a sample string";
use type Interfaces.C.size_t;
begin
ada_elaboration;
--
Ada.Text_IO.Put_Line ("======= inside myService");
-- print the string given by char*
Ada.Text_IO.Put_Line (Interfaces.C.Strings.Value (inBuffer));
-- the int
Ada.Text_IO.Put_Line (Natural'Image (Natural (anInteger)));
-- current value of the char* to be used as OUT buffer
Ada.Text_IO.Put_Line (Interfaces.C.Strings.Value (outBuffer));
-- use the char* to be used as out
Interfaces.C.Strings.Update
(Item => outBuffer,
Offset => 0,
Str => myString & Interfaces.C.To_Ada (Interfaces.C.nul), -- "& Interfaces.C.To_Ada(Interfaces.C.nul)" is equivalent to "& Character'Val(0)"
Check => false);
usedBufferSize := Interfaces.C.int (Interfaces.C.Strings.Strlen (outBuffer) - 1); -- see later java code and traces
end myService;
end ada_interface;
<小时>
现在是Java代码:
加载和映射服务到库的类:
Now the Java code:
Class to load and map services to the library:
package tst;
import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.Pointer;
import com.sun.jna.ptr.IntByReference;
public class Ada_Lib {
public interface My_Ada_Lib extends Library {
My_Ada_Lib instance = (My_Ada_Lib) Native.loadLibrary("libadalib", My_Ada_Lib.class);
My_Ada_Lib synchronizedInstance = (My_Ada_Lib) Native.synchronizedLibrary(instance);
void Renamed_myService (
Pointer inBuffer,
int anInteger,
byte[] outBuffer,
int outBufferSize,
IntByReference usedBufferSize
);
}
}
调用库的类
package tst;
import com.sun.jna.Memory;
import com.sun.jna.Native;
import com.sun.jna.Pointer;
import com.sun.jna.ptr.IntByReference;
import tst.Ada_Lib.My_Ada_Lib;
public class TestMyLib {
private static My_Ada_Lib theLib = Ada_Lib.My_Ada_Lib.synchronizedInstance;
public static void main(String[] args) {
String lorem = "Sin autem ad adulescentiam perduxissent, dirimi tamen interdum contentione vel uxoriae condicionis vel commodi alicuius, quod idem adipisci uterque non posset. Quod si qui longius in amicitia provecti essent, tamen saepe labefactari, si in honoris contentionem incidissent; pestem enim nullam maiorem esse amicitiis quam in plerisque pecuniae cupiditatem, in optimis quibusque honoris certamen et gloriae; ex quo inimicitias maximas saepe inter amicissimos exstitisse." +
"
" +
"Quanta autem vis amicitiae sit, ex hoc intellegi maxime potest, quod ex infinita societate generis humani, quam conciliavit ipsa natura, ita contracta res est et adducta in angustum ut omnis caritas aut inter duos aut inter paucos iungeretur." +
"
" +
"Haec subinde Constantius audiens et quaedam referente Thalassio doctus, quem eum odisse iam conpererat lege communi, scribens ad Caesarem blandius adiumenta paulatim illi subtraxit, sollicitari se simulans ne, uti est militare otium fere tumultuosum, in eius perniciem conspiraret, solisque scholis iussit esse contentum palatinis et protectorum cum Scutariis et Gentilibus, et mandabat Domitiano, ex comite largitionum, praefecto ut cum in Syriam venerit, Gallum, quem crebro acciverat, ad Italiam properare blande hortaretur et verecunde.
";
// in params
int inputInt = 25;
Pointer p_Lorem = new Memory(lorem.length()+1); // +1 for C's
p_Lorem.setString(0, lorem); // offset 0, no need to start at another offset
// in param but to used for out buffer
String stubOut = "Hello World ! 0123456789 ";
int maxBufferSize = (stubOut.length());
byte[] buffer = new byte[maxBufferSize];
buffer = stubOut.getBytes();
IntByReference usedBufferSize = new IntByReference(0); // any value works, since it is used as out param
System.out.println("-------------------- Call to Lib ----------------------------");
// call the lib !
theLib.Renamed_myService(p_Lorem, inputInt, buffer, maxBufferSize, usedBufferSize);
System.out.println("--------------------- Back to java --------------------------");
System.out.println("In Java: used buffer size = " + usedBufferSize.getValue());
System.out.println("In Java: read outBuffer as String = " + Native.toString(buffer));
System.out.println("In Java: read outBuffer as String with returned used buffer size = " + new String(buffer,0,usedBufferSize.getValue()));
}
}
<小时>
Java 控制台输出(JNA 调试为真)
Output from a java console (with JNA debug to true)
Looking in classpath from sun.misc.Launcher$AppClassLoader@4e0e2f2a for /com/sun/jna/win32-x86-64/jnidispatch.dll
Found library resource at jar:file:/ [...]
Looking for library 'libadalib'
Adding paths from jna.library.path: null
Trying libadalib.dll
Adding system paths: []
Trying libadalib.dll
Looking for lib- prefix
Trying liblibadalib.dll
Looking in classpath from sun.misc.Launcher$AppClassLoader@4e0e2f2a for libadalib
Found library resource at file:/<path>/TestMyLib/bin/libadalib.dll
Looking in <path>TestMyLibinlibadalib.dll
Found library 'libadalib' at <path>TestMyLibinlibadalib.dll
-------------------- Call to Lib ----------------------------
======= inside myService
Sin autem ad adulescentiam perduxissent, dirimi tamen interdum contentione vel uxoriae condicionis vel commodi alicuius, quod idem adipisci uterque non posset. Quod si qui longius in amicitia provecti essent, tamen saepe labefactari, si in honoris contentionem incidissent; pestem enim nullam maiorem esse amicitiis quam in plerisque pecuniae cupiditatem, in optimis quibusque honoris certamen et gloriae; ex quo inimicitias maximas saepe inter amicissimos exstitisse.
Quanta autem vis amicitiae sit, ex hoc intellegi maxime potest, quod ex infinita societate generis humani, quam conciliavit ipsa natura, ita contracta res est et adducta in angustum ut omnis caritas aut inter duos aut inter paucos iungeretur.
Haec subinde Constantius audiens et quaedam referente Thalassio doctus, quem eum odisse iam conpererat lege communi, scribens ad Caesarem blandius adiumenta paulatim illi subtraxit, sollicitari se simulans ne, uti est militare otium fere tumultuosum, in eius perniciem conspiraret, solisque scholis iussit esse contentum palatinis et protectorum cum Scutariis et Gentilibus, et mandabat Domitiano, ex comite largitionum, praefecto ut cum in Syriam venerit, Gallum, quem crebro acciverat, ad Italiam properare blande hortaretur et verecunde.
25
Hello World ! 0123456789
--------------------- Back to java --------------------------
In Java: used buffer size = 22
In Java: read outBuffer as String = This is a sample string // reads the full buffer
In Java: read outBuffer as String with returned used buffer size = This is a sample strin // reads a length of 22 (so the 'g' is missing)
<小时>
现在，Ada 库也可以使用匹配的 .h 文件轻松地与 C 或 C++ 接口:
Now the Ada library can also be easily interfaced with C or C++, using a matching .h file:
void myService (char* inBuffer, // as in string
int anInteger, // as in param
char* outBuffer, // used as out buffer, but initalized by calling code
int outBufferSize, // the initaliaed size
int usedBufferSize // used as out param, the actually used size
);
<小时>
如何在从 Eclipse 调用时调试库?
How to debug the lib while called from Eclipse ?
使用 Gnat Pro Studio (GPS)，您可以进入调试器视图并将 gdb 附加到您的 java 应用程序进程的 PID(对于 Windows).但是，如果没有以下技巧，您将无法设置断点.
Using Gnat Pro Studio (GPS), you can go in the debugger view and attach gdb to the PID (for windows) of your java application process. However, without the following trick, you won't be able to set breakpoints.
诀窍是在 DLL 内有一个无限循环(用于开发目的).
The trick is to have an infinite loop inside the DLL (for dev purposes).
正文:
while flag loop
null;
end loop;
广告文件:
flag : boolean := true; -- in private part
一旦 gdb 设法附加到正在运行的 DLL 代码(无限循环)，gdb 就会中断.
Once the gdb manages to attach to the running DLL code (infinite loop), the gdb will break.
在循环中放置一个断点，并在 gdb c 中输入类型.它会打断你的循环.
Put a breakpoint in your loop, and the type in gdb c.
It will break in your loop.
在代码中的其他地方放置另一个断点，然后输入以下 set flag := false，然后输入 c.
Put another breakpoint elsewhere in code, then type the follwong set flag := false, and then c.
现在 gdb 应该继续下一个断点.
Now the gdb should continue to next breakpoint.
(或使用n"(下一个)gdb 指令随意调试.)
(Or use the "n" (next) gdb instruction to debug at your own will.)
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