Add @Owning and @NotOwning

Author: Earthcomputer

gradle.properties

@@ -14,7 +14,7 @@
 # limitations under the License.
 #
 
-projectVersion=26.0.2
+projectVersion=27.0.0
 kotlin.code.style=official
 kotlin.mpp.stability.nowarn=true
 kotlin.stdlib.default.dependency=false

src/jvmMain/java/org/jetbrains/annotations/NotOwning.java

@@ -0,0 +1,47 @@
+package org.jetbrains.annotations;
+
+import java.io.Closeable;
+import java.io.InputStream;
+import java.io.StringWriter;
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.util.Properties;
+
+/**
+ * Indicates that responsibility for closing a {@link Closeable} resource is <em>not</em> transferred.
+ *
+ * <p>
+ * When marked on a method, the return value of the method is still owned and managed by the callee and therefore the
+ * caller must <em>not</em> close it. For example, a class may encapsulate an {@code OutputStream}, and expose it via a
+ * getter. The getter does not transfer responsibility for closing the stream.
+ *
+ * <p>
+ * When marked on a parameter, the callee does not take responsibility for closing the {@code Closeable}, and
+ * responsibility for closing it stays with the caller. For example, {@link Properties#load(InputStream)} doesn't close
+ * its parameter, and relying on that method to close the {@code InputStream} would be a mistake.
+ *
+ * <p>
+ * When marked on a class or interface implementing {@code Closeable}, indicates that this class and its subclasses do
+ * <em>not</em> contain resources which must be closed, and therefore not closing them won't lead to any resource leak.
+ * For example, {@link StringWriter} does not hold any external resources despite implementing {@code Closeable}, and
+ * closing it has no effect. Note that this does <em>not</em> mean that the class <em>cannot</em> be closed, only that
+ * it does not <em>have</em> to be closed.
+ *
+ * <p>
+ * This annotation also could be used as a meta-annotation, to define other annotations for convenience.
+ *
+ * <p>
+ * This annotation may be used by tools to check when a closeable resource hasn't been closed or closed by the wrong
+ * party. Note that this annotation has no effect when used for types that don't implement {@link Closeable}.
+ *
+ * @see Owning
+ */
+@Documented
+@Retention(RetentionPolicy.CLASS)
+@Target({ElementType.METHOD, ElementType.PARAMETER, ElementType.TYPE})
+@ApiStatus.Experimental
+public @interface NotOwning {
+}

src/jvmMain/java/org/jetbrains/annotations/Owning.java

@@ -0,0 +1,57 @@
+package org.jetbrains.annotations;
+
+import java.io.BufferedWriter;
+import java.io.Closeable;
+import java.io.Writer;
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.nio.file.Files;
+
+/**
+ * Indicates a transfer of responsibility for closing a {@link Closeable} resource.
+ *
+ * <p>
+ * When marked on a method, the responsibility for closing the return value of this method is transferred to the caller.
+ * For example, the {@link Files#newInputStream} method constructs an {@code InputStream} and returns it, then the
+ * caller is responsible for closing this {@code InputStream}.
+ *
+ * <p>
+ * When marked on a parameter, the responsibility for closing is transferred from the caller to the callee. For example,
+ * the following method's parameter may be annotated with {@code @Owning}:
+ * <pre>
+ * {@code
+ * public static void closeQuietly(@Owning Closeable resource) {
+ *     try {
+ *         resource.close();
+ *     } catch (IOException ignored) {
+ *     }
+ * }
+ * }
+ * </pre>
+ * Another example is {@link BufferedWriter#BufferedWriter(Writer)} which wraps a {@code Writer}, as the responsibility
+ * for closing the wrapped writer is transferred away from the caller (to the {@code BufferedWriter}).
+ *
+ * <p>
+ * When marked on a class or interface implementing {@code Closeable}, indicates that this class and its subclasses
+ * contain resources which must be closed, and therefore {@link Closeable#close close()} <em>must</em> be called at some
+ * point. This is the default assumption for most closeable classes; this annotation may be used to override a
+ * {@link NotOwning} annotation in a superclass.
+ *
+ * <p>
+ * This annotation also could be used as a meta-annotation, to define other annotations for convenience.
+ *
+ * <p>
+ * This annotation may be used by tools to check when a closeable resource hasn't been closed or closed by the wrong
+ * party. Note that this annotation has no effect when used for types that don't implement {@link Closeable}.
+ *
+ * @see NotOwning
+ */
+@Documented
+@Retention(RetentionPolicy.CLASS)
+@Target({ElementType.METHOD, ElementType.PARAMETER, ElementType.TYPE})
+@ApiStatus.Experimental
+public @interface Owning {
+}