1 files changed, 92 insertions, 0 deletions

diff --git a/subprojects/language/src/main/java/tools/refinery/language/library/ClasspathBasedLibrary.java b/subprojects/language/src/main/java/tools/refinery/language/library/ClasspathBasedLibrary.java
new file mode 100644
index 00000000..56bb8b96
--- /dev/null
+++ b/subprojects/language/src/main/java/tools/refinery/language/library/ClasspathBasedLibrary.java
@@ -0,0 +1,92 @@
+/*
+ * SPDX-FileCopyrightText: 2024 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package tools.refinery.language.library;
+
+import org.eclipse.emf.common.util.URI;
+import org.eclipse.xtext.naming.QualifiedName;
+
+import java.nio.file.Path;
+import java.util.*;
+
+public abstract class ClasspathBasedLibrary implements RefineryLibrary {
+        private final Class<?> context;
+        private final QualifiedName prefix;
+        private final URI rootUri;
+
+        protected ClasspathBasedLibrary(Class<?> context, QualifiedName prefix) {
+        this.context = context == null ? getClass() : context;
+        this.prefix = prefix;
+                var contextPath = this.context.getCanonicalName().replace('.', '/') + ".class";
+                var contextResource = this.context.getClassLoader().getResource(contextPath);
+                if (contextResource == null) {
+                        throw new IllegalStateException("Failed to find library context");
+                }
+                var contextUri = URI.createURI(contextResource.toString());
+                var segments = Arrays.copyOf(contextUri.segments(), contextUri.segmentCount() - 1);
+                rootUri = URI.createHierarchicalURI(contextUri.scheme(), contextUri.authority(), contextUri.device(),
+                                segments, null, null);
+        }
+
+        protected ClasspathBasedLibrary(QualifiedName prefix) {
+                this(null, prefix);
+        }
+
+        @Override
+        public Optional<URI> resolveQualifiedName(QualifiedName qualifiedName, List<Path> libraryPaths) {
+                if (qualifiedName.startsWith(prefix)) {
+                        return getLibraryUri(context, qualifiedName);
+                }
+                return Optional.empty();
+        }
+
+        @Override
+        public Optional<QualifiedName> getQualifiedName(URI uri, List<Path> libraryPaths) {
+                if (!uri.isHierarchical() ||
+                                !Objects.equals(rootUri.scheme(), uri.scheme()) ||
+                                !Objects.equals(rootUri.authority(), uri.authority()) ||
+                                !Objects.equals(rootUri.device(), uri.device()) ||
+                                rootUri.segmentCount() >= uri.segmentCount()) {
+                        return Optional.empty();
+                }
+                int rootSegmentCount = rootUri.segmentCount();
+                int uriSegmentCount = uri.segmentCount();
+                if (!uri.segment(uriSegmentCount - 1).endsWith(RefineryLibrary.FILE_NAME_SUFFIX)) {
+                        return Optional.empty();
+                }
+                var segments = new ArrayList<String>();
+                int i = 0;
+                while (i < rootSegmentCount) {
+                        if (!rootUri.segment(i).equals(uri.segment(i))) {
+                                return Optional.empty();
+                        }
+                        i++;
+                }
+                while (i < uriSegmentCount) {
+                        var segment = uri.segment(i);
+                        if (i == uriSegmentCount - 1) {
+                                segment = segment.substring(0, segment.length() - RefineryLibrary.FILE_NAME_SUFFIX.length());
+                        }
+                        segments.add(segment);
+                        i++;
+                }
+                var qualifiedName = QualifiedName.create(segments);
+                if (!qualifiedName.startsWith(prefix)) {
+                        return Optional.empty();
+                }
+                return Optional.of(qualifiedName);
+        }
+
+        public static Optional<URI> getLibraryUri(Class<?> context, QualifiedName qualifiedName) {
+                var packagePath = context.getPackageName().replace('.', '/');
+                var libraryPath = String.join("/", qualifiedName.getSegments());
+                var resourceName = "%s/%s%s".formatted(packagePath, libraryPath, RefineryLibrary.FILE_NAME_SUFFIX);
+                var resource = context.getClassLoader().getResource(resourceName);
+                if (resource == null) {
+                        return Optional.empty();
+                }
+                return Optional.of(URI.createURI(resource.toString()));
+        }
+}