From 1341a2f8d51c22a5e7f11459301ab330f61476e2 Mon Sep 17 00:00:00 2001
From: Curtis Rueden <ctrueden@wisc.edu>
Date: Wed, 10 Jul 2024 15:31:05 -0500
Subject: [PATCH] Add simpler SharedMemory creation methods

There are only two cases: create or attach.
---
 src/main/java/org/apposed/appose/NDArray.java |  2 +-
 .../java/org/apposed/appose/SharedMemory.java | 27 ++++++++++++++++---
 src/main/java/org/apposed/appose/Types.java   |  2 +-
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/src/main/java/org/apposed/appose/NDArray.java b/src/main/java/org/apposed/appose/NDArray.java
index 61b21cb..5bcc956 100644
--- a/src/main/java/org/apposed/appose/NDArray.java
+++ b/src/main/java/org/apposed/appose/NDArray.java
@@ -76,7 +76,7 @@ public NDArray(final SharedMemory sharedMemory, final DType dType, final Shape s
 	 * @param shape array shape
 	 */
 	public NDArray(final DType dType, final Shape shape) {
-		this(SharedMemory.create(null, true,
+		this(SharedMemory.create(null,
 			safeInt(shape.numElements() * dType.bytesPerElement())), dType, shape);
 	}
 
diff --git a/src/main/java/org/apposed/appose/SharedMemory.java b/src/main/java/org/apposed/appose/SharedMemory.java
index 9a8a841..d68d13b 100644
--- a/src/main/java/org/apposed/appose/SharedMemory.java
+++ b/src/main/java/org/apposed/appose/SharedMemory.java
@@ -42,6 +42,28 @@
  */
 public interface SharedMemory extends AutoCloseable {
 
+	/**
+	 * Creates a new shared memory block.
+	 *
+	 * @param name   the unique name for the requested shared memory, specified
+	 *               as a string. If {@code null} is supplied for the name, a novel
+	 *               name will be generated.
+	 * @param size   size in bytes.
+	 */
+	static SharedMemory create(String name, int size) {
+		return createOrAttach(name, true, size);
+	}
+
+	/**
+	 * Attaches to an existing shared memory block.
+	 *
+	 * @param name   the unique name for the requested shared memory, specified
+	 *               as a string.
+	 */
+	static SharedMemory attach(String name, int size) {
+		return createOrAttach(name, false, size);
+	}
+
 	/**
 	 * Creates a new shared memory block or attaches to an existing shared
 	 * memory block.
@@ -52,9 +74,9 @@ public interface SharedMemory extends AutoCloseable {
 	 *               name will be generated.
 	 * @param create whether a new shared memory block is created ({@code true})
 	 *               or an existing one is attached to ({@code false}).
-	 * @param size   size in bytes
+	 * @param size   size in bytes, or 0 if create==false
 	 */
-	static SharedMemory create(String name, boolean create, int size) {
+	static SharedMemory createOrAttach(String name, boolean create, int size) {
 		if (size < 0) {
 			throw new IllegalArgumentException("'size' must be a positive integer");
 		}
@@ -64,7 +86,6 @@ static SharedMemory create(String name, boolean create, int size) {
 		if (!create && name == null) {
 			throw new IllegalArgumentException("'name' can only be null if create=true");
 		}
-
 		ServiceLoader<ShmFactory> loader = ServiceLoader.load(ShmFactory.class);
 		for (ShmFactory factory: loader) {
 			SharedMemory shm = factory.create(name, create, size);
diff --git a/src/main/java/org/apposed/appose/Types.java b/src/main/java/org/apposed/appose/Types.java
index 2b495f8..4a869ef 100644
--- a/src/main/java/org/apposed/appose/Types.java
+++ b/src/main/java/org/apposed/appose/Types.java
@@ -161,7 +161,7 @@ private static Object processValue(Object value) {
 					case "shm":
 						final String name = (String) map.get("name");
 						final int size = (int) map.get("size");
-						return SharedMemory.create(name, false, size);
+						return SharedMemory.attach(name, size);
 					case "ndarray":
 						final SharedMemory shm = (SharedMemory) map.get("shm");
 						final DType dType = toDType((String) map.get("dtype"));