structured_sources: Allow build_tgt to be added as source

In some cases, there is a need to use a built library as a "source" for
another target. Specifically Java JAR might want to contain their own
native JNI libraries in order to provide a single file "executable".

mesonbuild/interpreter/interpreter.py

@@ -2367,7 +2367,7 @@ def func_structured_sources(
             self, node: mparser.BaseNode,
             args: T.Tuple[object, T.Optional[T.Dict[str, object]]],
             kwargs: 'TYPE_kwargs') -> build.StructuredSources:
-        valid_types = (str, mesonlib.File, build.GeneratedList, build.CustomTarget, build.CustomTargetIndex, build.GeneratedList)
+        valid_types = (str, mesonlib.File, build.GeneratedList, build.CustomTarget, build.CustomTargetIndex, build.GeneratedList, build.BuildTarget)
         sources: T.Dict[str, T.List[T.Union[mesonlib.File, 'build.GeneratedTypes']]] = collections.defaultdict(list)
 
         for arg in mesonlib.listify(args[0]):

test cases/java/9 jni/meson.build

@@ -21,18 +21,14 @@ cc.has_header('jni.h', dependencies: [jni_dep], required: true)
 # Assert that the platform-specific include directory is included in the compiler arguments.
 cc.has_header('jni_md.h', dependencies: [jni_dep], required: true)
 
-# generate native headers
 subdir('src')
-subdir('lib')
 
 test(
   'jnitest',
   java,
   args: [
-    '-Djava.library.path=@0@'.format(fs.parent(jnijava.full_path())),
     '-jar',
     jnijar,
   ],
   protocol : 'exitcode',
-  depends : [jnijava],
 )

test cases/java/9 jni/src/com/mesonbuild/JniTest.java

@@ -1,15 +1,43 @@
 package com.mesonbuild;
 
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.InputStream;
+import java.io.IOException;
+
 public final class JniTest {
+    private static String libname = "jnijava";
+    static {
+        String fullname = System.mapLibraryName(libname);
+        // this is somewhat hacky, but attempt to split off the extension
+        int ext = fullname.indexOf(".");
+        if (ext < 0)
+            ext = fullname.length();
+        try {
+            File fslib = File.createTempFile(fullname.substring(0, ext), fullname.substring(ext));
+            fslib.setReadable(true);
+            fslib.setWritable(true, true);
+            fslib.setExecutable(true);
+
+            InputStream istream = JniTest.class.getResourceAsStream("/" + fullname);
+            FileOutputStream ostream = new FileOutputStream(fslib);
+            istream.transferTo(ostream);
+            istream.close();
+            ostream.close();
+
+            System.load(fslib.getAbsolutePath());
+
+            fslib.deleteOnExit();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     private static native int jni_test();
 
     public static void main(String[] args) {
         if (jni_test() != Configured.FINGERPRINT) {
             throw new RuntimeException("jdk_test() did not return 0");
         }
     }
-
-    static {
-        System.loadLibrary("jnijava");
-    }
 }

test cases/java/9 jni/src/com/mesonbuild/meson.build

@@ -9,3 +9,5 @@ sources += configured
 native_headers = javamod.native_headers(
   sources, package: 'com.mesonbuild', classes: ['JniTest'])
 native_header_includes = include_directories('.')
+
+subdir('native')

test cases/java/9 jni/lib/meson.build → test cases/java/9 jni/src/com/mesonbuild/native/meson.build

@@ -1,4 +1,4 @@
-sources = [
+native_sources = [
   files(
     'native.c',
     'com_mesonbuild_JniTest.c',
@@ -8,11 +8,7 @@ sources = [
 
 jnijava = shared_module(
   'jnijava',
-  sources,
+  native_sources,
   dependencies : [jni_dep],
   include_directories : [native_header_includes]
 )
-
-jnijava_dep = declare_dependency(
-  link_with : jnijava
-)

test cases/java/9 jni/src/meson.build

@@ -6,4 +6,5 @@ jnijar = jar(
   'jnijar',
   sources,
   main_class : 'com.mesonbuild.JniTest',
+  java_resources : structured_sources(jnijava)
 )