Check length of list

1 files changed, 19 insertions, 0 deletions

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
index 1999cc8..6bbd93b 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
@@ -916,11 +916,30 @@ public class JavaTransient0Generator implements Generator {
 
         statements.addAll(generateDecode(size, NativeTypes.INT_64));
 
+        statements.add(new JavaIfStatement(
+            new JavaBinaryOperation(
+                JavaBinaryOperator.GREATER_THAN,
+                new JavaRef(size),
+                new JavaStaticFieldAccess(JavaTypeRef.INT_BOXED, JavaIdentifier.of("MAX_VALUE"))
+            ),
+            new JavaBlock(List.of(
+                new JavaThrowStatement(new JavaNewExpression(
+                    JavaTypeRef.IO_EXCEPTION,
+                    List.of(new JavaStringLiteral("Lists longer than Integer.MAX_VALUE are not supported"))
+                ))
+            )),
+            new JavaBlock(List.of())
+        ));
+
         statements.add(new JavaLocalVariableDeclaration(
             Optional.empty(),
             target,
             Optional.of(new JavaNewExpression(
                 JavaTypeRef.arrayList(this.javaGenerator.generateReferenceTypeRef(elementType)),
+                // We've checked above that the size is less than
+                // Integer.MAX_VALUE, so casting to an int is safe.
+                // (This doesn't check for negatives, but ArrayList::new() fails
+                // for negative values anyway.)
                 List.of(new JavaCast(JavaTypeRef.INT, new JavaRef(size)))
             ))
         ));