Generate the enums of jmeos-core from the catalog

codegen/src/main/java/FunctionsGenerator.java

@@ -23,6 +23,8 @@ public class FunctionsGenerator {
     // Enum names extracted from the JSON "enums" section.
     // These are mapped to int in Java (JNR-FFI represents C enums as int).
     private final Set<String> enumNames = new HashSet<>();
+    /** The enums of the catalog, in its order, each written as a Java enum by {@link #writeEnumClasses}. */
+    private final List<JsonNode> enumDefs = new ArrayList<>();
     /** Struct names the catalog defines, used to spot a by-value struct return. */
     private final Set<String> structNames = new HashSet<>();
     /** Fields of each struct the catalog defines, keyed by struct name. */
@@ -241,6 +243,7 @@ private void run(String inputPath, String outputPath) throws IOException {
         Files.createDirectories(out.getParent());
         Files.writeString(out, content);
         System.out.println("Written: " + out.toAbsolutePath());
+        writeEnumClasses(out.getParent());
         System.out.println("=== Done ===");
     }
 
@@ -481,11 +484,61 @@ private void collectEnumNames(JsonNode root) {
                 JsonNode nameNode = e.get("name");
                 if (nameNode != null) {
                     enumNames.add(nameNode.asText());
+                    enumDefs.add(e);
                 }
             }
         }
     }
 
+    /**
+     * Writes one Java enum per enum of the catalog a binding reaches, under its C name and with
+     * the values MEOS gives its constants, beside {@code GeneratedFunctions}: the enums of the
+     * public headers of an enabled family, neither those of {@code meos_internal.h} nor those of
+     * a vendored library.
+     */
+    private void writeEnumClasses(Path dir) throws IOException {
+        int written = 0;
+        for (JsonNode e : enumDefs) {
+            if (emitsEnum(e)) {
+                Files.writeString(dir.resolve(e.get("name").asText() + ".java"), enumSource(e));
+                written++;
+            }
+        }
+        System.out.println("Enums written: " + written + " of " + enumDefs.size());
+    }
+
+    /** Whether the enum belongs to the public surface this run generates. */
+    private boolean emitsEnum(JsonNode e) {
+        JsonNode file = e.get("file");
+        JsonNode vendored = e.get("vendored");
+        return (vendored == null || !vendored.asBoolean())
+                && (file == null || !file.asText().startsWith("meos_internal"))
+                && familyEnabled(familyOf(e));
+    }
+
+    /** The Java source of an enum of the catalog. */
+    static String enumSource(JsonNode e) {
+        String name = e.get("name").asText();
+        JsonNode file = e.get("file");
+        StringBuilder sb = new StringBuilder("package functions;\n\n");
+        sb.append("/** {@code ").append(name).append("} as ")
+                .append(file == null ? "MEOS" : "{@code " + file.asText() + "}")
+                .append(" declares it. */\n");
+        sb.append("public enum ").append(name).append(" {\n");
+        JsonNode values = e.get("values");
+        for (int i = 0; i < values.size(); i++) {
+            JsonNode v = values.get(i);
+            sb.append("\t").append(v.get("name").asText()).append("(").append(v.get("value").asLong())
+                    .append(i + 1 < values.size() ? "),\n" : ");\n");
+        }
+        sb.append("\n\tprivate final int value;\n\n");
+        sb.append("\t").append(name).append("(int value) {\n\t\tthis.value = value;\n\t}\n\n");
+        sb.append("\t/** The value MEOS gives this constant. */\n");
+        sb.append("\tpublic int getValue() {\n\t\treturn value;\n\t}\n");
+        sb.append("}\n");
+        return sb.toString();
+    }
+
     private FunctionDef parseFunctionDef(JsonNode fn) {
         String name = fn.get("name").asText();
 
@@ -609,10 +662,6 @@ private String mapCTypeToJava(String cType) {
             // becomes Pointer, breaking every h3index/th3index binding.
             case "H3Index"                          -> "long";
 
-            // Explicit enum names (in case not in JSON enums section)
-            case "interpType", "RTreeSearchOp",
-                 "tempSubtype", "spatialRel",
-                 "errorCode"                        -> "int";
             default                                 -> "Pointer";
         };
     }
@@ -781,8 +830,6 @@ private String generateFile(List<FunctionDef> functions) {
                 import jnr.ffi.byref.PointerByReference;
                 import jnr.ffi.Struct;
                 import utils.JarLibraryLoader;
-                import utils.meosCatalog.MeosEnums.meosType;
-                import utils.meosCatalog.MeosEnums.meosOper;
                 import functions.MeosErrorHandler;
 
                 import java.time.*;

codegen/src/test/java/FunctionsGeneratorTest.java

@@ -163,10 +163,10 @@ void unknownType() throws Exception {
         }
 
         @ParameterizedTest
-        @ValueSource(strings = {"interpType", "RTreeSearchOp", "tempSubtype", "spatialRel", "errorCode"})
-        @DisplayName("explicit enum names → int")
-        void explicitEnums(String cType) throws Exception {
-            assertEquals("int", mapJava(cType));
+        @ValueSource(strings = {"interpType", "IndexSearchOp", "tempSubtype", "spatialRel", "errorCode"})
+        @DisplayName("a name the catalog states no enum of is not an enum")
+        void enumOnlyFromCatalog(String cType) throws Exception {
+            assertEquals("Pointer", mapJava(cType));
         }
 
         @Test
@@ -376,7 +376,7 @@ void enumsPresent() throws Exception {
             String json = """
                 {
                   "enums": [
-                    {"name": "RTreeSearchOp"},
+                    {"name": "IndexSearchOp"},
                     {"name": "interpType"}
                   ],
                   "functions": []
@@ -396,7 +396,7 @@ void enumsPresent() throws Exception {
             @SuppressWarnings("unchecked")
             Set<String> names = (Set<String>) enumNamesField.get(generator);
 
-            assertTrue(names.contains("RTreeSearchOp"));
+            assertTrue(names.contains("IndexSearchOp"));
             assertTrue(names.contains("interpType"));
             assertEquals(2, names.size());
         }
@@ -418,6 +418,76 @@ void noEnumsSection() throws Exception {
         }
     }
 
+    // =========================================================================
+    // The Java enums of the catalog
+    // =========================================================================
+
+    @Nested
+    @DisplayName("enum classes")
+    class EnumClassTests {
+
+        private JsonNode enumNode(String json) throws Exception {
+            return new ObjectMapper().readTree(json);
+        }
+
+        private boolean emits(JsonNode e) throws Exception {
+            Method m = FunctionsGenerator.class.getDeclaredMethod("emitsEnum", JsonNode.class);
+            m.setAccessible(true);
+            return (boolean) m.invoke(generator, e);
+        }
+
+        @Test
+        @DisplayName("an enum keeps its C name and the value MEOS gives each constant")
+        void enumSourceKeepsNamesAndValues() throws Exception {
+            String src = FunctionsGenerator.enumSource(enumNode("""
+                {"name": "MeosType", "file": "meos_catalog.h", "family": "CORE",
+                 "values": [{"name": "T_UNKNOWN", "value": 0}, {"name": "T_DOUBLE2", "value": 8},
+                            {"name": "T_FLOAT8", "value": 11}]}
+                """));
+            assertTrue(src.startsWith("package functions;"));
+            assertTrue(src.contains("public enum MeosType {"));
+            assertTrue(src.contains("\tT_UNKNOWN(0),\n\tT_DOUBLE2(8),\n\tT_FLOAT8(11);\n"));
+            assertTrue(src.contains("public int getValue()"));
+        }
+
+        @Test
+        @DisplayName("the enums of a public header are written, internal and vendored ones are not")
+        void emitsPublicEnumsOnly() throws Exception {
+            assertTrue(emits(enumNode("""
+                {"name": "IndexSearchOp", "file": "meos.h", "family": "CORE", "vendored": false,
+                 "values": [{"name": "INDEX_OVERLAPS", "value": 0}]}
+                """)));
+            assertFalse(emits(enumNode("""
+                {"name": "SkipListType", "file": "meos_internal.h", "family": "CORE", "vendored": false,
+                 "values": [{"name": "TIMESTAMPTZ", "value": 0}]}
+                """)));
+            assertFalse(emits(enumNode("""
+                {"name": "ENDIANS", "file": "pc_api.h", "family": "POINTCLOUD", "vendored": true,
+                 "values": [{"name": "PC_XDR", "value": 0}]}
+                """)));
+        }
+
+        @Test
+        @DisplayName("run writes each enum beside the generated functions")
+        void runWritesEnumFiles() throws Exception {
+            Path input = tempDir.resolve("idl.json");
+            Files.writeString(input, """
+                {"enums": [{"name": "IndexSearchOp", "file": "meos.h", "family": "CORE",
+                            "values": [{"name": "INDEX_OVERLAPS", "value": 0},
+                                       {"name": "INDEX_ADJACENT", "value": 20}]},
+                           {"name": "SkipListType", "file": "meos_internal.h", "family": "CORE",
+                            "values": [{"name": "TIMESTAMPTZ", "value": 0}]}],
+                 "functions": []}
+                """);
+            Path out = tempDir.resolve("functions/GeneratedFunctions.java");
+            run.invoke(generator, input.toString(), out.toString());
+            Path written = tempDir.resolve("functions/IndexSearchOp.java");
+            assertTrue(Files.exists(written));
+            assertTrue(Files.readString(written).contains("INDEX_ADJACENT(20);"));
+            assertFalse(Files.exists(tempDir.resolve("functions/SkipListType.java")));
+        }
+    }
+
     // =========================================================================
     // run(): end-to-end / integration
     // =========================================================================
@@ -940,7 +1010,7 @@ void fileHeaderCorrect() throws Exception {
         void enumFromJsonSection() throws Exception {
             String json = """
                 {
-                  "enums": [{"name": "MyOp"}],
+                  "enums": [{"name": "MyOp", "file": "meos.h", "family": "CORE", "values": [{"name": "MY_OP", "value": 0}]}],
                   "functions": [{
                     "name": "do_op",
                     "returnType": {"c": "void"},