jvm: Enforce max stack, add more string tests

gkbrk · gkbrk · commit f92d35ba3cc8 · 2018-12-26T20:51:29.000Z
diff --git a/example/StringTest.java b/example/StringTest.java
@@ -1,8 +1,8 @@
 package jvmtest;
 
-class Rot13 {
-    public static void main(String[] args) {
-        System.out.println(rot13("Gb trg gb gur bgure fvqr!"));
+class StringTest {
+    public static String reverseString(String s) {
+        return new StringBuilder(s).reverse().toString();
     }
 
     public static String rot13(String str) {
@@ -23,4 +23,4 @@ private static char rot13(char ch) {
         }
         return ch;
     }
-}
+}
diff --git a/pyjvm/Machine.py b/pyjvm/Machine.py
@@ -353,8 +353,9 @@ def execute_code(self, frame):
             inst = Inst(code[frame.ip])
             #print(frame.ip, inst)
 
-            #if len(frame.stack) > frame.max_stack + 1:
-            #    print("MAX STACK")
+            if len(frame.stack) > frame.max_stack + 1:
+                print("MAX STACK")
+                break
 
             if inst in OPCODES:
                 OPCODES[inst](frame)
@@ -582,8 +583,9 @@ def execute_code(self, frame):
                     cl = self.class_files[name]
                     if cl.canHandleMethod(nat.name, nat.desc):
                         ret = cl.handleMethod(nat.name, nat.desc, frame)
-                        if not nat.desc.endswith('V'):
-                            frame.push(ret)
+                    else:
+                        frame.stack.pop()
+                        
             elif inst == Inst.INVOKESTATIC:
                 index = read_unsigned_short(frame)
 
diff --git a/pyjvm/jstdlib/JavaClass.py b/pyjvm/jstdlib/JavaClass.py
@@ -17,7 +17,7 @@ def python_initialize(self, *args):
         pass
 
     def __repr__(self):
-        return '<{} - {}>'.format(self.name(), self.instance_fields)
+        return f'<{self.name()} - {self.instance_fields}>'
 
     def get_field(self, name):
         return self.instance_fields[name]
@@ -32,4 +32,4 @@ def handleMethod(self, name, desc, frame):
         pass
 
     def handleStatic(self, name, desc, frame):
-        pass
+        pass
diff --git a/pyjvm/jstdlib/Rng.py b/pyjvm/jstdlib/Rng.py
@@ -11,4 +11,4 @@ def canHandleMethod(self, name, desc):
 
     def handleMethod(self, name, desc, frame, code, machine, ip):
         if name == 'generate':
-            frame.stack.append(random.randint(0, 100))
+            frame.stack.append(random.randint(0, 100))
diff --git a/pyjvm/jstdlib/String.py b/pyjvm/jstdlib/String.py
@@ -12,10 +12,8 @@ def handleMethod(self, name, desc, frame):
         super().handleMethod(name, desc, frame)
         if name == 'length':
             val = frame.pop()
-            #frame.push(len(val))
             return len(val)
         elif name == 'charAt':
             index = frame.pop()
             s = frame.pop()
-            #frame.push(s[index])
-            return s[index]
+            return s[index]
diff --git a/pyjvm/jstdlib/StringBuilder.py b/pyjvm/jstdlib/StringBuilder.py
@@ -9,7 +9,10 @@ def python_initialize(self, *args):
         self.string = ''
 
     def canHandleMethod(self, name, desc):
-        return name in ['append', 'toString']
+        if name == '<init>' and desc == '(Ljava/lang/String;)V':
+            return True
+        
+        return name in ['append', 'toString', 'reverse']
 
     def handleMethod(self, name, desc, frame):
         super().handleMethod(name, desc, frame)
@@ -18,9 +21,14 @@ def handleMethod(self, name, desc, frame):
             v1 = frame.stack.pop()
             v1.string += v2
             return v1
-            #frame.stack.append(v1)
         elif name == 'toString':
             v1 = frame.stack.pop()
-            frame.stack.pop()
-            #frame.stack.append(v1.string)
-            return v1.string
+            return v1.string
+        elif name == 'reverse':
+            v1 = frame.stack.pop()
+            v1.string = v1.string[::-1]
+            return v1
+        elif name == '<init>' and desc == '(Ljava/lang/String;)V':
+            s = frame.stack.pop()
+            v1 = frame.stack.pop()
+            v1.string = s
diff --git a/run_unittest.py b/run_unittest.py
@@ -49,16 +49,20 @@ def test_recursive_fibonacci(self):
         self.assertEqual(self.jvm
             .call_function('jvmtest/IntegerTest/recursiveFibonacci', 7), 13)
 
-class Rot13Test(unittest.TestCase):
+class StringTest(unittest.TestCase):
     def setUp(self):
         self.jvm = Machine()
         load_stdlib_classes(self.jvm)
-        self.jvm.load_class_file('example/Rot13.class')
+        self.jvm.load_class_file('example/StringTest.class')
 
     def test_rot13_hello_world(self):
         self.assertEqual(self.jvm
-            .call_function('jvmtest/Rot13/rot13', 'Hello World!')
-                                                , 'Uryyb Jbeyq!')
+            .call_function('jvmtest/StringTest/rot13', 'Hello World!')
+                                                     , 'Uryyb Jbeyq!')
+
+    def test_reverse_string(self):
+        r = self.jvm.call_function('jvmtest/StringTest/reverseString', 'Test message!')
+        self.assertEqual(r, '!egassem tseT')
 
 class InstanceTest(unittest.TestCase):
     def setUp(self):

Original file line number	Diff line number	Diff line change
`@@ -1,8 +1,8 @@`
`1`	`1`	`package jvmtest;`
`2`	`2`
`3`		`-class Rot13 {`
`4`		`- public static void main(String[] args) {`
`5`		`- System.out.println(rot13("Gb trg gb gur bgure fvqr!"));`
	`3`	`+class StringTest {`
	`4`	`+ public static String reverseString(String s) {`
	`5`	`+ return new StringBuilder(s).reverse().toString();`
`6`	`6`	`}`
`7`	`7`
`8`	`8`	`public static String rot13(String str) {`
`@@ -23,4 +23,4 @@ private static char rot13(char ch) {`
`23`	`23`	`}`
`24`	`24`	`return ch;`
`25`	`25`	`}`
`26`		`-}`
	`26`	`+}`