feat: Refactor the references support

References collect by appearance position in text, not just a
name.

Closes #702

Signed-off-by: Anton Grigorev <[email protected]>

Author: grianbrcom

server/src/main/java/com/broadcom/lsp/cobol/domain/modules/ServiceModule.java

@@ -62,10 +62,10 @@ protected void configure() {
     bind(WatcherService.class).to(WatcherServiceImpl.class);
     bind(FileSystemService.class).to(WorkspaceFileService.class);
     bind(SubroutineService.class).to(SubroutineServiceImpl.class);
+    bind(Occurrences.class).to(ElementOccurrences.class);
 
     bindFormations();
     bindCompletions();
-    bindReferences();
     bindCodeActions();
 
     bindInterceptor(
@@ -103,18 +103,6 @@ private void bindCompletions() {
     bind(CompletionStorage.class).annotatedWith(named("Snippets")).to(Snippets.class);
   }
 
-  private void bindReferences() {
-    bind(Occurrences.class).to(SemanticElementOccurrences.class);
-    Multibinder<SemanticLocations> referenceBinding =
-        newSetBinder(binder(), SemanticLocations.class);
-    referenceBinding.addBinding().to(VariableLocations.class);
-    referenceBinding.addBinding().to(ParagraphLocations.class);
-    referenceBinding.addBinding().to(SectionLocations.class);
-    referenceBinding.addBinding().to(CopybookLocations.class);
-    referenceBinding.addBinding().to(ConstantLocations.class);
-    referenceBinding.addBinding().to(SubroutineLocations.class);
-  }
-
   private void bindCodeActions() {
     bind(CodeActions.class);
     Multibinder<CodeActionProvider> codeActionBinding =

server/src/main/java/com/broadcom/lsp/cobol/service/delegates/references/ConstantLocations.java

@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2020 Broadcom.
+ * The term "Broadcom" refers to Broadcom Inc. and/or its subsidiaries.
+ *
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *    Broadcom, Inc. - initial API and implementation
+ *
+ */
+package com.broadcom.lsp.cobol.service.delegates.references;
+
+import com.broadcom.lsp.cobol.core.semantics.outline.RangeUtils;
+import com.broadcom.lsp.cobol.service.CobolDocumentModel;
+import com.broadcom.lsp.cobol.service.delegates.validations.AnalysisResult;
+import lombok.NonNull;
+import lombok.Value;
+import org.eclipse.lsp4j.*;
+
+import javax.annotation.Nullable;
+import java.util.*;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * This occurrences provider resolves the requests for the semantic elements based on its positions.
+ */
+public class ElementOccurrences implements Occurrences {
+    @Override
+    public @NonNull List<Location> findDefinitions(@Nullable CobolDocumentModel document, @NonNull TextDocumentPositionParams position) {
+        if (document == null) return Collections.emptyList();
+        return findElementByPosition(document, position).definitions;
+    }
+
+    @Override
+    public @NonNull List<Location> findReferences(@Nullable CobolDocumentModel document, @NonNull TextDocumentPositionParams position, @NonNull ReferenceContext context) {
+        if (document == null) return Collections.emptyList();
+        Element element = findElementByPosition(document, position);
+        List<Location> references = element.usages;
+        if (context.isIncludeDeclaration()) {
+            references = new ArrayList<>(references);
+            references.addAll(element.definitions);
+        }
+        return references;
+    }
+
+    @Override
+    public @NonNull List<DocumentHighlight> findHighlights(@Nullable CobolDocumentModel document, @NonNull TextDocumentPositionParams position) {
+        if (document == null) return Collections.emptyList();
+        return findReferences(document, position, new ReferenceContext(true)).stream()
+                .filter(byUri(position))
+                .map(toDocumentHighlight())
+                .collect(Collectors.toList());
+    }
+
+    private static Element findElementByPosition(CobolDocumentModel document, TextDocumentPositionParams position) {
+        AnalysisResult result = document.getAnalysisResult();
+        return findElementByPosition(result.getVariableDefinitions(), result.getVariableUsages(), position)
+                .or(() -> findElementByPosition(result.getParagraphDefinitions(), result.getParagraphUsages(), position))
+                .or(() -> findElementByPosition(result.getSectionDefinitions(), result.getSectionUsages(), position))
+                .or(() -> findElementByPosition(result.getConstantDefinitions(), result.getConstantUsages(), position))
+                .or(() -> findElementByPosition(result.getCopybookDefinitions(), result.getCopybookUsages(), position))
+                .or(() -> findElementByPosition(result.getSubroutineDefinitions(), result.getSubroutineUsages(), position))
+                .orElseGet(() -> new Element(List.of(), List.of()));
+    }
+
+    @Value
+    private static class Element {
+        List<Location> definitions;
+        List<Location> usages;
+    }
+
+    private static Optional<Element> findElementByPosition(
+            Map<String, List<Location>> definitions,
+            Map<String, List<Location>> usages,
+            TextDocumentPositionParams position) {
+        return Stream.concat(definitions.entrySet().stream(), usages.entrySet().stream())
+                .filter(entry -> entry.getValue().stream().anyMatch(location -> isInside(position, location)))
+                .findFirst()
+                .map(Map.Entry::getKey)
+                .map(name -> new Element(definitions.getOrDefault(name, List.of()), usages.getOrDefault(name, List.of())));
+    }
+
+    static boolean isInside(TextDocumentPositionParams position, Location location) {
+        return position.getTextDocument().getUri().equals(location.getUri())
+                && !RangeUtils.isBefore(position.getPosition(), location.getRange().getStart())
+                && !RangeUtils.isAfter(position.getPosition(), location.getRange().getEnd());
+    }
+
+    @NonNull
+    private static Predicate<Location> byUri(@NonNull TextDocumentPositionParams position) {
+        return location -> location.getUri().equals(position.getTextDocument().getUri());
+    }
+
+    @NonNull
+    private static Function<Location, DocumentHighlight> toDocumentHighlight() {
+        return location -> new DocumentHighlight(location.getRange(), DocumentHighlightKind.Text);
+    }
+}