Implement rb_check_symbol_cstr()

Author: eregon

CHANGELOG.md

@@ -40,6 +40,7 @@ Compatibility:
 * Implemented `keyword_init: true` for `Struct.new` (#1789, @XrXr).
 * Implemented `MatchData#dup` (#1792, @XrXr).
 * Implemented a native storage strategy for arrays to allow better C extension compatibility.
+* Implemented `rb_check_symbol_cstr` (#1814).
 
 Performance:
 

src/main/c/cext/ruby.c

@@ -3283,7 +3283,8 @@ ID rb_check_id_cstr(const char *ptr, long len, rb_encoding *enc) {
 }
 
 VALUE rb_check_symbol_cstr(const char *ptr, long len, rb_encoding *enc) {
-  rb_tr_error("rb_check_symbol_cstr not implemented");
+  VALUE str = rb_enc_str_new(ptr, len, enc);
+  return RUBY_CEXT_INVOKE("rb_check_symbol_cstr", str);
 }
 
 int rb_econv_has_convpath_p(const char* from_encoding, const char* to_encoding) {

src/main/java/org/truffleruby/cext/CExtNodes.java

@@ -1589,4 +1589,15 @@ protected Object unwrapFunction() {
             return new ValueWrapperManager.WrapperFunction();
         }
     }
+
+    @CoreMethod(names = "rb_check_symbol_cstr", onSingleton = true, required = 1)
+    public abstract static class RbCheckSymbolCStrNode extends CoreMethodArrayArgumentsNode {
+
+        @Specialization
+        protected DynamicObject checkSymbolCStr(DynamicObject str) {
+            final DynamicObject sym = getContext().getSymbolTable().getSymbolIfExists(rope(str));
+            return sym == null ? nil() : sym;
+        }
+
+    }
 }

src/main/java/org/truffleruby/core/symbol/SymbolTable.java

@@ -105,29 +105,38 @@ public DynamicObject getSymbol(String string) {
 
     @TruffleBoundary
     public DynamicObject getSymbol(Rope rope) {
-        if (rope instanceof NativeRope) {
-            rope = ((NativeRope) rope).toLeafRope();
-        }
-
-        if (rope.isAsciiOnly() && rope.getEncoding() != USASCIIEncoding.INSTANCE) {
-            rope = rope.withEncoding(USASCIIEncoding.INSTANCE, CodeRange.CR_7BIT);
-        }
-
-        final RopeKey ropeKey = new RopeKey(rope, hashing);
-
+        final RopeKey ropeKey = createRopeKey(rope);
         final DynamicObject symbol = symbolMap.get(ropeKey);
         if (symbol != null) {
             return symbol;
         }
 
-        final Rope cachedRope = ropeCache.getRope(rope);
+        final Rope cachedRope = ropeCache.getRope(ropeKey.getRope());
         final DynamicObject newSymbol = createSymbol(cachedRope);
         // Use a RopeKey with the cached Rope in symbolMap, since the Symbol refers to it and so we
         // do not keep rope alive unnecessarily.
         final RopeKey cachedRopeKey = new RopeKey(cachedRope, hashing);
         return symbolMap.addInCacheIfAbsent(cachedRopeKey, newSymbol);
     }
 
+    @TruffleBoundary
+    public DynamicObject getSymbolIfExists(Rope rope) {
+        final RopeKey ropeKey = createRopeKey(rope);
+        return symbolMap.get(ropeKey);
+    }
+
+    private RopeKey createRopeKey(Rope rope) {
+        if (rope instanceof NativeRope) {
+            rope = ((NativeRope) rope).toLeafRope();
+        }
+
+        if (rope.isAsciiOnly() && rope.getEncoding() != USASCIIEncoding.INSTANCE) {
+            rope = rope.withEncoding(USASCIIEncoding.INSTANCE, CodeRange.CR_7BIT);
+        }
+
+        return new RopeKey(rope, hashing);
+    }
+
     private DynamicObject createSymbol(Rope cachedRope) {
         final String string = RopeOperations.decodeOrEscapeBinaryRope(cachedRope);
         return Layouts.SYMBOL.createSymbol(