Support slashes in rule names

jni/internal/cc_jni_library.bzl

@@ -176,9 +176,10 @@ def cc_jni_library(
         [`cc_library`](https://docs.bazel.build/versions/main/be/c-cpp.html#cc_library), except for:
         `linkshared` (always `True`), `linkstatic` (always `True`), `data` (runfiles are not supported)
     """
-    macos_library_name = "lib%s.dylib" % name
-    unix_library_name = "lib%s.so" % name
-    windows_library_name = "%s.dll" % name
+    path, sep, basename = name.rpartition("/")
+    macos_library_name = "%s%slib%s.dylib" % (path, sep, basename)
+    unix_library_name = "%s%slib%s.so" % (path, sep, basename)
+    windows_library_name = "%s%s%s.dll" % (path, sep, basename)
 
     # Arguments to set on the visible target, not the intermediate cc_binary.
     tags = cc_binary_args.pop("tags", default = None)
@@ -190,13 +191,13 @@ def cc_jni_library(
     java_coverage_helper_name = "%s_java_coverage_helper" % name
     java_jni_coverage_helper_library(
         name = java_coverage_helper_name,
-        library_name = name,
+        library_name = basename,
     )
 
     cc_coverage_helper_name = "%s_cc_coverage_helper" % name
     cc_jni_coverage_helper_library(
         name = cc_coverage_helper_name,
-        library_name = name,
+        library_name = basename,
     )
 
     # Simple concatenation is compatible with select, append is not.

jni/tools/native_loader/src/main/java/com/github/fmeum/rules_jni/RulesJni.java

@@ -94,29 +94,31 @@ public static void loadLibrary(String name, String absolutePathToPackage) {
   }
 
   synchronized private static void loadLibrary(String name, URL libraryResource) {
-    if (LOADED_LIBS.containsKey(name)) {
-      if (!libraryResource.toString().equals(LOADED_LIBS.get(name).canonicalPath)) {
+    String basename = libraryBasename(name);
+    if (LOADED_LIBS.containsKey(basename)) {
+      if (!libraryResource.toString().equals(LOADED_LIBS.get(basename).canonicalPath)) {
         throw new UnsatisfiedLinkError(String.format(
             "Cannot load two native libraries with same basename ('%s') from different paths\nFirst library: %s\nSecond library: %s\n",
-            name, LOADED_LIBS.get(name).canonicalPath, libraryResource));
+            basename, LOADED_LIBS.get(basename).canonicalPath, libraryResource));
       }
       return;
     }
     try {
       Path tempDir = getOrCreateTempDir();
-      String mappedName = System.mapLibraryName(name);
+      String mappedName = System.mapLibraryName(basename);
       int lastDot = mappedName.lastIndexOf('.');
       Path tempFile = Files.createTempFile(
           tempDir, mappedName.substring(0, lastDot) + "_", mappedName.substring(lastDot));
-      LOADED_LIBS.put(name, new NativeLibraryInfo(libraryResource.toString(), tempFile.toFile()));
+      LOADED_LIBS.put(
+          basename, new NativeLibraryInfo(libraryResource.toString(), tempFile.toFile()));
       try (InputStream in = libraryResource.openStream()) {
         Files.copy(in, tempFile, StandardCopyOption.REPLACE_EXISTING);
         System.load(tempFile.toAbsolutePath().toString());
       }
     } catch (IOException e) {
       throw new UnsatisfiedLinkError(e.getMessage());
     }
-    CoverageHelper.initCoverage(name);
+    CoverageHelper.initCoverage(basename);
   }
 
   private static Path getOrCreateTempDir() throws IOException {
@@ -126,12 +128,18 @@ private static Path getOrCreateTempDir() throws IOException {
     return tempDir;
   }
 
+  private static String libraryBasename(String name) {
+    return name.substring(name.lastIndexOf('/') + 1);
+  }
+
   private static String libraryRelativePath(String name) {
     if (name == null) {
       throw new NullPointerException("name must not be null");
     }
-    return String.format("%s_%s_%s/%s", name, OsCpuUtils.CANONICAL_OS, OsCpuUtils.CANONICAL_CPU,
-        System.mapLibraryName(name));
+    String basename = libraryBasename(name);
+    String path = name.substring(0, name.length() - basename.length());
+    return String.format("%s%s_%s_%s/%s", path, basename, OsCpuUtils.CANONICAL_OS,
+        OsCpuUtils.CANONICAL_CPU, System.mapLibraryName(basename));
   }
 
   private static void failOnNullResource(URL resource, String name) {

tests/native_loader/src/main/java/com/example/os/BUILD.bazel

@@ -7,7 +7,7 @@ java_jni_library(
         "OsUtils.java",
     ],
     native_libs = [
-        "//native_loader/src/main/native/com/example/os",
+        "//native_loader/src/main/native/com/example/os:impl/os",
     ],
     visibility = [
         "//native_loader/src/main/native/com/example/os:__subpackages__",

tests/native_loader/src/main/java/com/example/os/OsUtils.java

@@ -21,9 +21,9 @@ public class OsUtils {
 
   static {
     String packagePath = OsUtils.class.getPackage().getName().replace(".", "/");
-    RulesJni.loadLibrary("os", "/" + packagePath);
+    RulesJni.loadLibrary("impl/os", "/" + packagePath);
     // Verify that loading the library twice does not result in errors.
-    RulesJni.loadLibrary("os", OsUtils.class);
+    RulesJni.loadLibrary("impl/os", OsUtils.class);
   }
 
   public static native int setenv(String name, String value);

tests/native_loader/src/main/native/com/example/os/BUILD.bazel

@@ -1,7 +1,7 @@
 load("@fmeum_rules_jni//jni:defs.bzl", "cc_jni_library")
 
 cc_jni_library(
-    name = "os",
+    name = "impl/os",
     testonly = True,
     srcs = [
         "onload.cpp",