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Allow null operands in compiled SpEL numeric operator expressions

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Closes gh-22358
This commit is contained in:
Juergen Hoeller
2019-05-02 17:27:49 +02:00
parent 9d55884a86
commit 8a48c5ad86
2 changed files with 241 additions and 9 deletions
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97
spring-expression/src/main/java/org/springframework/expression/spel/ast/Operator.java
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@@ -1,5 +1,5 @@
/*
* Copyright 2002-2018 the original author or authors.
* Copyright 2002-2019 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -113,7 +113,8 @@ public abstract class Operator extends SpelNodeImpl {
SpelNodeImpl right = getRightOperand();
String leftDesc = left.exitTypeDescriptor;
String rightDesc = right.exitTypeDescriptor;
Label elseTarget = new Label();
Label endOfIf = new Label();
boolean unboxLeft = !CodeFlow.isPrimitive(leftDesc);
boolean unboxRight = !CodeFlow.isPrimitive(rightDesc);
DescriptorComparison dc = DescriptorComparison.checkNumericCompatibility(
@@ -123,20 +124,104 @@ public abstract class Operator extends SpelNodeImpl {
cf.enterCompilationScope();
left.generateCode(mv, cf);
cf.exitCompilationScope();
if (unboxLeft) {
CodeFlow.insertUnboxInsns(mv, targetType, leftDesc);
if (CodeFlow.isPrimitive(leftDesc)) {
CodeFlow.insertBoxIfNecessary(mv, leftDesc);
unboxLeft = true;
}
cf.enterCompilationScope();
right.generateCode(mv, cf);
cf.exitCompilationScope();
if (CodeFlow.isPrimitive(rightDesc)) {
CodeFlow.insertBoxIfNecessary(mv, rightDesc);
unboxRight = true;
}
// This code block checks whether the left or right operand is null and handles
// those cases before letting the original code (that only handled actual numbers) run
Label rightIsNonNull = new Label();
mv.visitInsn(DUP); // stack: left/right/right
mv.visitJumpInsn(IFNONNULL, rightIsNonNull); // stack: left/right
// here: RIGHT==null LEFT==unknown
mv.visitInsn(SWAP); // right/left
Label leftNotNullRightIsNull = new Label();
mv.visitJumpInsn(IFNONNULL, leftNotNullRightIsNull); // stack: right
// here: RIGHT==null LEFT==null
mv.visitInsn(POP); // stack: <nothing>
// load 0 or 1 depending on comparison instruction
switch (compInstruction1) {
case IFGE: // OpLT
case IFLE: // OpGT
mv.visitInsn(ICONST_0); // false - null is not < or > null
break;
case IFGT: // OpLE
case IFLT: // OpGE
mv.visitInsn(ICONST_1); // true - null is <= or >= null
break;
default:
throw new IllegalStateException("Unsupported: " + compInstruction1);
}
mv.visitJumpInsn(GOTO, endOfIf);
mv.visitLabel(leftNotNullRightIsNull); // stack: right
// RIGHT==null LEFT!=null
mv.visitInsn(POP); // stack: <nothing>
// load 0 or 1 depending on comparison instruction
switch (compInstruction1) {
case IFGE: // OpLT
case IFGT: // OpLE
mv.visitInsn(ICONST_0); // false - something is not < or <= null
break;
case IFLE: // OpGT
case IFLT: // OpGE
mv.visitInsn(ICONST_1); // true - something is > or >= null
break;
default:
throw new IllegalStateException("Unsupported: " + compInstruction1);
}
mv.visitJumpInsn(GOTO, endOfIf);
mv.visitLabel(rightIsNonNull); // stack: left/right
// here: RIGHT!=null LEFT==unknown
mv.visitInsn(SWAP); // stack: right/left
mv.visitInsn(DUP); // stack: right/left/left
Label neitherRightNorLeftAreNull = new Label();
mv.visitJumpInsn(IFNONNULL, neitherRightNorLeftAreNull); // stack: right/left
// here: RIGHT!=null LEFT==null
mv.visitInsn(POP2); // stack: <nothing>
switch (compInstruction1) {
case IFGE: // OpLT
case IFGT: // OpLE
mv.visitInsn(ICONST_1); // true - null is < or <= something
break;
case IFLE: // OpGT
case IFLT: // OpGE
mv.visitInsn(ICONST_0); // false - null is not > or >= something
break;
default:
throw new IllegalStateException("Unsupported: " + compInstruction1);
}
mv.visitJumpInsn(GOTO, endOfIf);
mv.visitLabel(neitherRightNorLeftAreNull); // stack: right/left
// neither were null so unbox and proceed with numeric comparison
if (unboxLeft) {
CodeFlow.insertUnboxInsns(mv, targetType, leftDesc);
}
// What we just unboxed might be a double slot item (long/double)
// so can't just use SWAP
// stack: right/left(1or2slots)
if (targetType == 'D' || targetType == 'J') {
mv.visitInsn(DUP2_X1);
mv.visitInsn(POP2);
}
else {
mv.visitInsn(SWAP);
}
// stack: left(1or2)/right
if (unboxRight) {
CodeFlow.insertUnboxInsns(mv, targetType, rightDesc);
}
// assert: SpelCompiler.boxingCompatible(leftDesc, rightDesc)
Label elseTarget = new Label();
Label endOfIf = new Label();
if (targetType == 'D') {
mv.visitInsn(DCMPG);
mv.visitJumpInsn(compInstruction1, elseTarget);