JS: Refactor metadata class a bit

javascript/extractor/src/com/semmle/js/parser/TypeScriptASTConverter.java

@@ -1599,7 +1599,7 @@ public class TypeScriptASTConverter {
   private Node convertMetaProperty(JsonObject node, SourceLocation loc) throws ParseError {
     Position metaStart = loc.getStart();
     String keywordKind =
-        metadata.getSyntaxKinds().get(node.getAsJsonPrimitive("keywordToken").getAsInt() + "").getAsString();
+        metadata.getSyntaxKindName(node.getAsJsonPrimitive("keywordToken").getAsInt());
     String identifier = keywordKind.equals("ImportKeyword") ? "import" : "new";
     Position metaEnd =
         new Position(
@@ -1977,7 +1977,7 @@ public class TypeScriptASTConverter {
 
   private String getOperator(JsonObject node) throws ParseError {
     int operatorId = node.get("operator").getAsInt();
-    switch (metadata.getSyntaxKindMap().get(operatorId)) {
+    switch (metadata.getSyntaxKindName(operatorId)) {
       case "PlusPlusToken":
         return "++";
       case "MinusMinusToken":
@@ -2201,7 +2201,7 @@ public class TypeScriptASTConverter {
   }
 
   private Node convertTypeOperator(JsonObject node, SourceLocation loc) throws ParseError {
-    String operator = metadata.getSyntaxKinds().get("" + node.get("operator").getAsInt()).getAsString();
+    String operator = metadata.getSyntaxKindName(node.get("operator").getAsInt());
     if (operator.equals("KeyOfKeyword")) {
       return new UnaryTypeExpr(loc, UnaryTypeExpr.Kind.Keyof, convertChildAsType(node, "type"));
     }
@@ -2519,12 +2519,7 @@ public class TypeScriptASTConverter {
    * <tt>ts.NodeFlags</tt> in enum.
    */
   private boolean hasFlag(JsonObject node, String flagName) {
-    JsonElement flagDescriptor = this.metadata.getNodeFlags().get(flagName);
-    if (flagDescriptor == null) {
-      throw new RuntimeException(
-          "Incompatible version of TypeScript installed. Missing node flag " + flagName);
-    }
-    int flagId = flagDescriptor.getAsInt();
+    int flagId = metadata.getNodeFlagId(flagName);
     JsonElement flags = node.get("flags");
     if (flags instanceof JsonPrimitive) {
       return (flags.getAsInt() & flagId) != 0;
@@ -2534,12 +2529,7 @@ public class TypeScriptASTConverter {
 
   /** Gets the numeric value of the syntax kind enum with the given name. */
   private int getSyntaxKind(String syntaxKind) {
-    JsonElement descriptor = this.metadata.getSyntaxKinds().get(syntaxKind);
-    if (descriptor == null) {
-      throw new RuntimeException(
-          "Incompatible version of TypeScript installed. Missing syntax kind " + syntaxKind);
-    }
-    return descriptor.getAsInt();
+    return metadata.getSyntaxKindId(syntaxKind);
   }
 
   /** Check whether a node has a child with a given name. */
@@ -2563,7 +2553,7 @@ public class TypeScriptASTConverter {
     if (node instanceof JsonObject) {
       JsonElement kind = ((JsonObject) node).get("kind");
       if (kind instanceof JsonPrimitive && ((JsonPrimitive) kind).isNumber())
-        return metadata.getSyntaxKindMap().get(kind.getAsInt());
+        return metadata.getSyntaxKindName(kind.getAsInt());
     }
     return null;
   }

javascript/extractor/src/com/semmle/js/parser/TypeScriptParserMetadata.java

@@ -17,14 +17,12 @@ import com.google.gson.JsonPrimitive;
 public class TypeScriptParserMetadata {
   private final JsonObject nodeFlags;
   private final JsonObject syntaxKinds;
-  private final Map<Integer, String> nodeFlagMap = new LinkedHashMap<>();
   private final Map<Integer, String> syntaxKindMap = new LinkedHashMap<>();
 
   public TypeScriptParserMetadata(JsonObject metadata) {
     this.nodeFlags = metadata.get("nodeFlags").getAsJsonObject();
     this.syntaxKinds = metadata.get("syntaxKinds").getAsJsonObject();
-    makeEnumIdMap(getNodeFlags(), getNodeFlagMap());
-    makeEnumIdMap(getSyntaxKinds(), getSyntaxKindMap());
+    makeEnumIdMap(syntaxKinds, syntaxKindMap);
   }
 
   /** Builds a mapping from ID to name given a TypeScript enum object. */
@@ -38,30 +36,41 @@ public class TypeScriptParserMetadata {
   }
 
   /**
-   * Returns the <code>NodeFlags</code> enum object from the TypeScript API.
+   * Returns the logical name associated with syntax kind ID <code>id</code>,
+   * or throws an exception if it does not exist.
    */
-  public JsonObject getNodeFlags() {
-    return nodeFlags;
+  String getSyntaxKindName(int id) {
+    String name = syntaxKindMap.get(id);
+    if (name == null) {
+      throw new RuntimeException(
+          "Incompatible version of TypeScript installed. Missing syntax kind ID " + id);
+    }
+    return name;
   }
 
   /**
-   * Returns the <code>SyntaxKind</code> enum object from the TypeScript API.
+   * Returns the syntax kind ID corresponding to the logical name <code>name</code>,
+   * or throws an exception if it does not exist.
    */
-  public JsonObject getSyntaxKinds() {
-    return syntaxKinds;
+  int getSyntaxKindId(String name) {
+    JsonElement elm = syntaxKinds.get(name);
+    if (elm == null) {
+      throw new RuntimeException(
+          "Incompatible version of TypeScript installed. Missing syntax kind " + name);
+    }
+    return elm.getAsInt();
   }
 
   /**
-   * Returns the mapping from node flag bit to its name.
+   * Returns the NodeFlag ID from the logical name <code>name</code>
+   * or throws an exception if it does not exist.
    */
-  public Map<Integer, String> getNodeFlagMap() {
-    return nodeFlagMap;
-  }
-
-  /**
-   * Returns the mapping from syntax kind ID to its name.
-   */
-  public Map<Integer, String> getSyntaxKindMap() {
-    return syntaxKindMap;
+  int getNodeFlagId(String name) {
+    JsonElement elm = nodeFlags.get(name);
+    if (elm == null) {
+      throw new RuntimeException(
+          "Incompatible version of TypeScript installed. Missing node flag " + name);
+    }
+    return elm.getAsInt();
   }
 }