[Addition] Added IniRenderer and IniRenderer test cases #137

pkl-core/src/main/java/org/pkl/core/IniRenderer.java

@@ -0,0 +1,247 @@
+/**
+ * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.pkl.core;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.io.Writer;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.regex.Pattern;
+import org.pkl.core.util.Nullable;
+import org.pkl.core.util.ini.IniUtils;
+
+// To instantiate this class, use ValueRenderers.properties().
+final class IniRenderer implements ValueRenderer {
+
+  private final Writer writer;
+  private final boolean omitNullProperties;
+  private final boolean restrictCharset;
+
+  public IniRenderer(Writer writer, boolean omitNullProperties, boolean restrictCharset) {
+    this.writer = writer;
+    this.omitNullProperties = omitNullProperties;
+    this.restrictCharset = restrictCharset;
+  }
+
+  @Override
+  public void renderDocument(Object value) {
+    new Visitor().renderDocument(value);
+  }
+
+  @Override
+  public void renderValue(Object value) {
+    new Visitor().renderValue(value);
+  }
+
+  public class Visitor implements ValueConverter<String> {
+
+    public void renderValue(Object value) {
+      write(convert(value), false, restrictCharset);
+    }
+
+    public void renderDocument(Object value) {
+      if (value instanceof Composite) {
+        doVisitMap(null, ((Composite) value).getProperties());
+      } else if (value instanceof Map) {
+        doVisitMap(null, (Map<?, ?>) value);
+      } else if (value instanceof Pair) {
+        Pair<?, ?> pair = (Pair<?, ?>) value;
+        doVisitKeyAndValue(null, pair.getFirst(), pair.getSecond());
+      } else {
+        throw new RendererException(
+            String.format(
+                "The top-level value of a Java properties file must have type `Composite`, `Map`, or `Pair`, but got type `%s`.",
+                value.getClass().getTypeName()));
+      }
+    }
+
+    private void doVisitMap(@Nullable String keyPrefix, Map<?, ?> map) {
+      for (Map.Entry<?, ?> entry : map.entrySet()) {
+        doVisitKeyAndValue(keyPrefix, entry.getKey(), entry.getValue());
+      }
+    }
+
+    private void doVisitKeyAndValue(@Nullable String keyPrefix, Object key, Object value) {
+      if (omitNullProperties && value instanceof PNull) {
+        return;
+      }
+      var baseKey = convert(key);
+      // gets existing key and appends the existing keypreifx if it's not null
+      var keyString = keyPrefix == null ? baseKey : keyPrefix + "." + baseKey;
+      // discovered a new section and writes key then writes the child values
+      // e.g. [example.dog]
+      if (value instanceof Composite) {
+        writeIniKey(keyString);
+        doVisitMap(keyString, ((Composite) value).getProperties());
+      } else if (value instanceof Map) {
+        writeIniKey(keyString);
+        doVisitMap(keyString, (Map<?, ?>) value);
+      } else {
+        writeIniValue(baseKey, convert(value));
+      }
+    }
+
+    @Override
+    public String convertNull() {
+      return "";
+    }
+
+    @Override
+    public String convertString(String value) {
+      return value;
+    }
+
+    @Override
+    public String convertBoolean(Boolean value) {
+      return value.toString();
+    }
+
+    @Override
+    public String convertInt(Long value) {
+      return value.toString();
+    }
+
+    @Override
+    public String convertFloat(Double value) {
+      return value.toString();
+    }
+
+    @Override
+    public String convertDuration(Duration value) {
+      throw new RendererException(
+          String.format(
+              "Values of type `Duration` cannot be rendered as Properties. Value: %s", value));
+    }
+
+    @Override
+    public String convertDataSize(DataSize value) {
+      throw new RendererException(
+          String.format(
+              "Values of type `DateSize` cannot be rendered as Properties. Value: %s", value));
+    }
+
+    @Override
+    public String convertPair(Pair<?, ?> value) {
+      throw new RendererException(
+          String.format(
+              "Values of type `Pair` cannot be rendered as Properties. Value: %s", value));
+    }
+
+    @Override
+    public String convertList(List<?> value) {
+      throw new RendererException(
+          String.format(
+              "Values of type `List` cannot be rendered as Properties. Value: %s", value));
+    }
+
+    @Override
+    public String convertSet(Set<?> value) {
+      throw new RendererException(
+          String.format("Values of type `Set` cannot be rendered as Properties. Value: %s", value));
+    }
+
+    @Override
+    public String convertMap(Map<?, ?> value) {
+      throw new RendererException(
+          String.format("Values of type `Map` cannot be rendered as Properties. Value: %s", value));
+    }
+
+    @Override
+    public String convertObject(PObject value) {
+      throw new RendererException(
+          String.format(
+              "Values of type `Object` cannot be rendered as Properties. Value: %s", value));
+    }
+
+    @Override
+    public String convertModule(PModule value) {
+      throw new RendererException(
+          String.format(
+              "Values of type `Module` cannot be rendered as Properties. Value: %s", value));
+    }
+
+    @Override
+    public String convertClass(PClass value) {
+      throw new RendererException(
+          String.format(
+              "Values of type `Class` cannot be rendered as Properties. Value: %s",
+              value.getSimpleName()));
+    }
+
+    @Override
+    public String convertTypeAlias(TypeAlias value) {
+      throw new RendererException(
+          String.format(
+              "Values of type `TypeAlias` cannot be rendered as Properties. Value: %s",
+              value.getSimpleName()));
+    }
+
+    @Override
+    public String convertRegex(Pattern value) {
+      throw new RendererException(
+          String.format(
+              "Values of type `Regex` cannot be rendered as Properties. Value: %s", value));
+    }
+
+    private void write(String value, boolean escapeSpace, boolean restrictCharset) {
+      try {
+        writer.write(IniUtils.renderPropertiesKeyOrValue(value, escapeSpace, restrictCharset));
+      } catch (IOException e) {
+        throw new RuntimeException(e);
+      }
+    }
+
+    private void writeIniValue(String key, String value) {
+      write(key, true, restrictCharset);
+      writeSeparator();
+      write(value, false, restrictCharset);
+      writeLineBreak();
+    }
+
+    private void writeIniKey(String keyValue) {
+      try {
+        // inserts a line break to make sure ini file is correct format
+        writeLineBreak();
+        writer.write('[');
+        write(keyValue, true, restrictCharset);
+        writer.write(']');
+        writeLineBreak();
+      } catch (IOException e) {
+        throw new UncheckedIOException(e);
+      }
+    }
+
+    private void writeSeparator() {
+      try {
+        writer.write(' ');
+        writer.write('=');
+        writer.write(' ');
+      } catch (IOException e) {
+        throw new RuntimeException(e);
+      }
+    }
+
+    private void writeLineBreak() {
+      try {
+        writer.write('\n');
+      } catch (IOException e) {
+        throw new UncheckedIOException(e);
+      }
+    }
+  }
+}

pkl-core/src/main/java/org/pkl/core/ValueRenderers.java

@@ -67,4 +67,15 @@ public static ValueRenderer properties(
       Writer writer, boolean omitNullProperties, boolean restrictCharset) {
     return new PropertiesRenderer(writer, omitNullProperties, restrictCharset);
   }
+
+  /**
+   * Creates a renderer for INI file format. If {@code omitNullProperties} is {@code true}, object
+   * properties and map entries whose value is {@code null} will not be rendered. If {@code
+   * restrictCharset} is {@code true} characters outside the printable US-ASCII charset range will
+   * be rendered as Unicode escapes
+   */
+  public static ValueRenderer ini(
+      Writer writer, boolean omitNullProperties, boolean restrictCharset) {
+    return new IniRenderer(writer, omitNullProperties, restrictCharset);
+  }
 }

pkl-core/src/main/java/org/pkl/core/util/ini/IniUtils.java

@@ -0,0 +1,65 @@
+/**
+ * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.pkl.core.util.ini;
+
+public class IniUtils {
+  // bitmap 32 bit need to escape ' ', ';'
+  private static final int[] bitmapEscapeSpace = new int[] {9728, 738197900, 268435456, 0};
+
+  private static final int[] bitmapNoEscapeSpace = new int[] {9728, 738197644, 268435456, 0};
+
+  private static final char[] hexDigitTable =
+      new char[] {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
+
+  private static final char[] hashTable =
+      new char[] {
+        ' ', 0, '"', '#', 0, 0, 0, '\'', 0, 't', 'n', 0, 0, 'r', 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        ':', ';', '\\', '=', 0, 0
+      };
+
+  public static String renderPropertiesKeyOrValue(
+      String value, boolean escapeSpace, boolean restrictCharset) {
+    if (value.isEmpty()) {
+      return "";
+    }
+    var builder = new StringBuilder();
+
+    if (!escapeSpace && value.charAt(0) == ' ') {
+      builder.append('\\');
+    }
+
+    for (var i = 0; i < value.length(); i++) {
+      var c = value.charAt(i);
+      var bitmap = escapeSpace ? bitmapEscapeSpace : bitmapNoEscapeSpace;
+      var isEscapeChar = c < 128 && (bitmap[c >> 5] & (1 << c)) != 0;
+
+      if (isEscapeChar) {
+        builder.append('\\').append(hashTable[c % 32]);
+      } else if (restrictCharset && (c < 32 || c > 126)) {
+        builder
+            .append('\\')
+            .append('u')
+            .append(hexDigitTable[c >> 12 & 0xF])
+            .append(hexDigitTable[c >> 8 & 0xF])
+            .append(hexDigitTable[c >> 4 & 0xF])
+            .append(hexDigitTable[c & 0xF]);
+      } else {
+        builder.append(c);
+      }
+    }
+    return builder.toString();
+  }
+}

pkl-core/src/test/kotlin/org/pkl/core/IniRendererTest.kt

@@ -0,0 +1,54 @@
+package org.pkl.core
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
+import org.pkl.core.util.IoUtils
+import java.io.StringWriter
+
+class IniRendererTest {
+  @Test
+  fun `render document`() {
+    val evaluator = Evaluator.preconfigured()
+    val module = evaluator.evaluate(ModuleSource.modulePath("org/pkl/core/iniRendererTest.pkl"))
+    val writer = StringWriter()
+    val renderer = ValueRenderers.ini(writer, true, false)
+
+    renderer.renderDocument(module)
+    val output = writer.toString()
+    val expected = IoUtils.readClassPathResourceAsString(javaClass, "iniRendererTest.ini")
+
+
+    assertThat(output).isEqualTo(expected)
+  }
+
+  @Test
+  fun `render unsupported document values`() {
+    val unsupportedValues = listOf(
+      "List()", "new Listing {}", "Map()", "new Mapping {}", "Set()",
+      "new PropertiesRenderer {}", "new Dynamic {}"
+    )
+
+    unsupportedValues.forEach {
+      val evaluator = Evaluator.preconfigured()
+      val renderer = ValueRenderers.ini(StringWriter(), true, false)
+
+      val module = evaluator.evaluate(ModuleSource.text("value = $it"))
+      assertThrows<RendererException> { renderer.renderValue(module) }
+    }
+  }
+
+  @Test
+  fun `rendered document ends in newline`() {
+    val module = Evaluator.preconfigured()
+      .evaluate(ModuleSource.text("foo { bar = 0 }"))
+
+    for (omitNullProperties in listOf(false, true)) {
+      for (restrictCharSet in listOf(false, true)) {
+        val writer = StringWriter()
+        ValueRenderers.ini(writer, omitNullProperties, restrictCharSet).renderDocument(module)
+        assertThat(writer.toString()).endsWith("\n")
+      }
+    }
+  }
+}