YAMLFindUsagesProvider to allow find usages in YAML-based languages

plugins/yaml/resources/META-INF/plugin.xml

@@ -13,6 +13,7 @@
     <lang.syntaxHighlighterFactory language="yaml" implementationClass="org.jetbrains.yaml.YAMLSyntaxHighlighterFactory"/>
     <colorSettingsPage implementation="org.jetbrains.yaml.YAMLColorsPage"/>
     <lang.braceMatcher language="yaml" implementationClass="org.jetbrains.yaml.YAMLPairedBraceMatcher"/>
+    <lang.findUsagesProvider language="yaml" implementationClass="org.jetbrains.yaml.YAMLFindUsagesProvider"/>
     <lang.foldingBuilder language="yaml" implementationClass="org.jetbrains.yaml.folding.YAMLFoldingBuilder"/>
     <fileTypeFactory implementation="org.jetbrains.yaml.YAMLFileTypeLoader"/>
     <editor.backspaceModeOverride language="yaml" implementationClass="com.intellij.codeInsight.editorActions.SmartBackspaceDisabler"/>

plugins/yaml/src/org/jetbrains/yaml/YAMLFindUsagesProvider.java

@@ -0,0 +1,70 @@
+package org.jetbrains.yaml;
+
+import com.intellij.lang.HelpID;
+import com.intellij.lang.cacheBuilder.WordsScanner;
+import com.intellij.lang.findUsages.FindUsagesProvider;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiNamedElement;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.yaml.psi.YAMLMapping;
+import org.jetbrains.yaml.psi.YAMLScalar;
+import org.jetbrains.yaml.psi.YAMLScalarText;
+import org.jetbrains.yaml.psi.YAMLSequence;
+
+/**
+ * @author shalupov
+ */
+public class YAMLFindUsagesProvider implements FindUsagesProvider {
+  @Nullable
+  @Override
+  public WordsScanner getWordsScanner() {
+    return new YAMLWordsScanner();
+  }
+
+  @Override
+  public boolean canFindUsagesFor(@NotNull PsiElement psiElement) {
+    return psiElement instanceof PsiNamedElement || psiElement instanceof YAMLScalar;
+  }
+
+  @Nullable
+  @Override
+  public String getHelpId(@NotNull PsiElement psiElement) {
+    return HelpID.FIND_OTHER_USAGES;
+  }
+
+  @NotNull
+  @Override
+  public String getType(@NotNull PsiElement element) {
+    if (element instanceof YAMLScalarText) {
+      return "scalar";
+    } else if (element instanceof YAMLSequence) {
+      return "sequence";
+    } else if (element instanceof YAMLMapping) {
+      return "mapping";
+    } else {
+      return "";
+    }
+  }
+
+  @NotNull
+  @Override
+  public String getDescriptiveName(@NotNull PsiElement element) {
+    final String name = element instanceof PsiNamedElement ? ((PsiNamedElement)element).getName() : null;
+    if (name != null) {
+      return name;
+    }
+
+    if (element instanceof YAMLScalar) {
+      return ((YAMLScalar)element).getTextValue();
+    }
+
+    return "<unnamed>";
+  }
+
+  @NotNull
+  @Override
+  public String getNodeText(@NotNull PsiElement element, boolean useFullName) {
+    return getDescriptiveName(element);
+  }
+}

plugins/yaml/src/org/jetbrains/yaml/YAMLWordsScanner.java

@@ -0,0 +1,22 @@
+package org.jetbrains.yaml;
+
+import com.intellij.lang.cacheBuilder.DefaultWordsScanner;
+import com.intellij.psi.tree.TokenSet;
+import org.jetbrains.yaml.lexer.YAMLFlexLexer;
+
+/**
+ * @author shalupov
+ */
+public class YAMLWordsScanner extends DefaultWordsScanner {
+  public YAMLWordsScanner() {
+    super(
+      new YAMLFlexLexer(),
+      TokenSet.create(
+        YAMLElementTypes.SCALAR_TEXT_VALUE,
+        YAMLElementTypes.SCALAR_PLAIN_VALUE,
+        YAMLElementTypes.SCALAR_QUOTED_STRING),
+      TokenSet.create(YAMLTokenTypes.COMMENT),
+      TokenSet.EMPTY);
+    setMayHaveFileRefsInLiterals(true);
+  }
+}