src/share/classes/com/sun/tools/javac/comp/Lower.java
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*** 1398,1407 ****
--- 1398,1523 ----
// need to go via this$n
return makeOuterThis(pos, c);
}
}
+ /** Optionally replace a try statement with an automatic resource management
+ * (ARM) block.
+ * @param tree The try statement to inspect.
+ * @return An ARM block, or the original try block if there are no
+ * resources to manage.
+ */
+ JCTree makeTry(JCTry tree) {
+ if (tree.resources.isEmpty()) {
+ return tree;
+ }
+ make_at(tree.pos());
+ JCBlock armBlock = makeArmBlock(tree.resources, tree.body, 0);
+ if (tree.catchers.isEmpty() && tree.finalizer == null)
+ result = translate(armBlock);
+ else
+ result = translate(make.Try(armBlock, tree.catchers, tree.finalizer));
+ return result;
+ }
+
+ private JCBlock makeArmBlock(List<JCTree> resources, JCBlock block, int depth) {
+ if (resources.isEmpty())
+ return block;
+
+ // Add resource declaration or expression to block statements
+ ListBuffer<JCStatement> stats = new ListBuffer<JCStatement>();
+ JCTree resource = resources.head;
+ JCExpression expr = null;
+ if (resource instanceof JCVariableDecl) {
+ JCVariableDecl var = (JCVariableDecl) resource;
+ expr = make.Ident(var.sym).setType(resource.type);
+ stats.add(var);
+ } else {
+ assert resource instanceof JCExpression;
+ VarSymbol syntheticArmVar =
+ new VarSymbol(SYNTHETIC | FINAL,
+ names.fromString("armVar" +
+ resource.pos +
+ target.syntheticNameChar()),
+ resource.type,
+ currentMethodSym);
+ JCVariableDecl syntheticArmVarDecl = make.VarDef(syntheticArmVar, (JCExpression)resource);
+ expr = (JCExpression)make.Ident(syntheticArmVar);
+ stats.add(syntheticArmVarDecl);
+ }
+
+ // Add primaryException declaration
+ VarSymbol primaryException =
+ new VarSymbol(SYNTHETIC,
+ names.fromString("primaryException" +
+ resource.pos +
+ target.syntheticNameChar()),
+ syms.throwableType,
+ currentMethodSym);
+ JCVariableDecl primaryExceptionTreeDecl = make.VarDef(primaryException, makeNull());
+ stats.add(primaryExceptionTreeDecl);
+
+ // Create catch clause that saves exception and then rethrows it
+ VarSymbol param =
+ new VarSymbol(FINAL|SYNTHETIC,
+ names.fromString("t" +
+ resource.pos +
+ target.syntheticNameChar()),
+ syms.throwableType,
+ currentMethodSym);
+ JCVariableDecl paramTree = make.VarDef(param, null);
+ JCStatement assign = make.Assignment(primaryException, make.Ident(param));
+ JCStatement rethrowStat = make.Throw(make.Ident(param));
+ JCBlock catchBlock = make.Block(0L, List.<JCStatement>of(assign, rethrowStat));
+ JCCatch catchClause = make.Catch(paramTree, catchBlock);
+
+ int oldPos = make.pos;
+ make.at(TreeInfo.endPos(block));
+ JCBlock finallyClause = makeArmFinallyClause(primaryException, expr);
+ make.at(oldPos);
+ JCTry outerTry = make.Try(makeArmBlock(resources.tail, block, depth + 1),
+ List.<JCCatch>of(catchClause),
+ finallyClause);
+ stats.add(outerTry);
+ return make.Block(0L, stats.toList());
+ }
+
+ private JCBlock makeArmFinallyClause(Symbol primaryException, JCExpression resource) {
+ // primaryException.addSuppressedException(catchException);
+ VarSymbol catchException =
+ new VarSymbol(0, make.paramName(2),
+ syms.throwableType,
+ currentMethodSym);
+ JCStatement addSuppressionStatement =
+ make.Exec(makeCall(make.Ident(primaryException),
+ names.fromString("addSuppressedException"),
+ List.<JCExpression>of(make.Ident(catchException))));
+
+ // try { resource.close(); } catch (e) { primaryException.addSuppressedException(e); }
+ JCBlock tryBlock =
+ make.Block(0L, List.<JCStatement>of(makeResourceCloseInvocation(resource)));
+ JCVariableDecl catchExceptionDecl = make.VarDef(catchException, null);
+ JCBlock catchBlock = make.Block(0L, List.<JCStatement>of(addSuppressionStatement));
+ List<JCCatch> catchClauses = List.<JCCatch>of(make.Catch(catchExceptionDecl, catchBlock));
+ JCTry tryTree = make.Try(tryBlock, catchClauses, null);
+
+ // if (resource != null) resourceClose;
+ JCExpression nullCheck = makeBinary(JCTree.NE,
+ make.Ident(primaryException),
+ makeNull());
+ JCIf closeIfStatement = make.If(nullCheck,
+ tryTree,
+ makeResourceCloseInvocation(resource));
+ return make.Block(0L, List.<JCStatement>of(closeIfStatement));
+ }
+
+ private JCStatement makeResourceCloseInvocation(JCExpression resource) {
+ // create resource.close() method invocation
+ JCExpression resourceClose = makeCall(resource, names.close, List.<JCExpression>nil());
+ return make.Exec(resourceClose);
+ }
+
/** Construct a tree that represents the outer instance
* <C.this>. Never pick the current `this'.
* @param pos The source code position to be used for the tree.
* @param c The qualifier class.
*/
*** 3403,3412 ****
--- 3519,3534 ----
// we don't generate code.
public void visitAnnotation(JCAnnotation tree) {
result = tree;
}
+ @Override
+ public void visitTry(JCTry tree) {
+ super.visitTry(tree);
+ result = makeTry(tree);
+ }
+
/**************************************************************************
* main method
*************************************************************************/
/** Translate a toplevel class and return a list consisting of