Migrate common shm size checking logic to helper

apposed · Jul 17, 2024 · 33f7cdd · 33f7cdd
1 parent 0ed6112
commit 33f7cdd
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Showing 4 changed files with 12 additions and 21 deletions.
diff --git a/src/main/java/org/apposed/appose/shm/ShmLinux.java b/src/main/java/org/apposed/appose/shm/ShmLinux.java
@@ -93,13 +93,8 @@ private SharedMemoryLinux(final String name, final boolean create, final int siz
 				shm_name = withLeadingSlash(name);
 				prevSize = getSHMSize(shm_name);
 			}
+			ShmUtils.checkSize(shm_name, prevSize, size);
 
-			final boolean alreadyExists = prevSize >= 0;
-			if (alreadyExists && prevSize < size) {
-				throw new RuntimeException("Shared memory segment already exists with smaller dimensions, data type or format. "
-								+ "Size of the existing shared memory segment cannot be smaller than the size of the proposed object. "
-								+ "Size of existing shared memory segment: " + prevSize + ", size of proposed object: " + size);
-			}
 			final int shmFd = LibRtOrC.shm_open(shm_name, O_CREAT | O_RDWR, 0666);
 			if (shmFd < 0) {
 				throw new RuntimeException("shm_open failed, errno: " + Native.getLastError());

diff --git a/src/main/java/org/apposed/appose/shm/ShmMacOS.java b/src/main/java/org/apposed/appose/shm/ShmMacOS.java
@@ -64,13 +64,8 @@ private SharedMemoryMacOS(final String name, final boolean create, final int siz
 				shm_name = withLeadingSlash(name);
 				prevSize = getSHMSize(shm_name);
 			}
+			ShmUtils.checkSize(shm_name, prevSize, size);
 
-			final boolean alreadyExists = prevSize >= 0;
-			if (alreadyExists && prevSize < size) {
-				throw new RuntimeException("Shared memory segment already exists with smaller dimensions, data type or format. "
-								+ "Size of the existing shared memory segment cannot be smaller than the size of the proposed object. "
-								+ "Size of existing shared memory segment: " + prevSize + ", size of proposed object: " + size);
-			}
 			//		shmFd = INSTANCE.shm_open(this.memoryName, O_RDWR, 0666);
 			final int shmFd = MacosHelpers.INSTANCE.create_shared_memory(shm_name, size);
 			if (shmFd < 0) {

diff --git a/src/main/java/org/apposed/appose/shm/ShmUtils.java b/src/main/java/org/apposed/appose/shm/ShmUtils.java
@@ -112,6 +112,15 @@ static String make_filename(int maxLength, String prefix) {
 		return name;
 	}
 
+	static void checkSize(String shmName, long prevSize, int size) {
+		final boolean alreadyExists = prevSize >= 0;
+		if (alreadyExists && prevSize < size) {
+			throw new RuntimeException("Shared memory segment '" + shmName + "' already exists with smaller size. "
+				+ "Size of the existing shared memory segment cannot be smaller than the size of the proposed object. "
+				+ "Size of existing shared memory segment: " + prevSize + ", size of proposed object: " + size);
+		}
+	}
+
 	private static String token_hex(int nbytes) {
 		final byte[] bytes = new byte[nbytes];
 		new Random().nextBytes(bytes);

diff --git a/src/main/java/org/apposed/appose/shm/ShmWindows.java b/src/main/java/org/apposed/appose/shm/ShmWindows.java
@@ -65,15 +65,7 @@ private SharedMemoryWindows(final String name, final boolean create, final int s
 				shm_name = nameMangle_TODO(name);
 				prevSize = getSHMSize(shm_name);
 			}
-
-			final boolean alreadyExists = prevSize >= 0;
-			if(alreadyExists &&prevSize<size)
-
-			{
-				throw new RuntimeException("Shared memory segment already exists with smaller dimensions, data type or format. "
-								+ "Size of the existing shared memory segment cannot be smaller than the size of the proposed object. "
-								+ "Size of existing shared memory segment: " + prevSize + ", size of proposed object: " + size);
-			}
+			ShmUtils.checkSize(shm_name, prevSize, size);
 
 			final WinNT.HANDLE shm_hMapFile = Kernel32.INSTANCE.CreateFileMapping(
 							WinBase.INVALID_HANDLE_VALUE,