Mercurial > jdk8-mips64-public > langtools / changeset

     1.1 --- a/src/share/classes/com/sun/tools/javac/comp/Lower.java	Fri Feb 18 16:17:44 2011 +0000
     1.2 +++ b/src/share/classes/com/sun/tools/javac/comp/Lower.java	Fri Feb 18 15:55:20 2011 -0800
     1.3 @@ -1425,25 +1425,55 @@
     1.4          }
     1.5      }
     1.6  
     1.7 -    /** Optionally replace a try statement with an automatic resource
     1.8 -     *  management (ARM) block.
     1.9 +    /**
    1.10 +     * Optionally replace a try statement with the desugaring of a
    1.11 +     * try-with-resources statement.  The canonical desugaring of
    1.12 +     *
    1.13 +     * try ResourceSpecification
    1.14 +     *   Block
    1.15 +     *
    1.16 +     * is
    1.17 +     *
    1.18 +     * {
    1.19 +     *   final VariableModifiers_minus_final R #resource = Expression;
    1.20 +     *   Throwable #primaryException = null;
    1.21 +     *
    1.22 +     *   try ResourceSpecificationtail
    1.23 +     *     Block
    1.24 +     *   catch (Throwable #t) {
    1.25 +     *     #primaryException = t;
    1.26 +     *     throw #t;
    1.27 +     *   } finally {
    1.28 +     *     if (#resource != null) {
    1.29 +     *       if (#primaryException != null) {
    1.30 +     *         try {
    1.31 +     *           #resource.close();
    1.32 +     *         } catch(Throwable #suppressedException) {
    1.33 +     *           #primaryException.addSuppressed(#suppressedException);
    1.34 +     *         }
    1.35 +     *       } else {
    1.36 +     *         #resource.close();
    1.37 +     *       }
    1.38 +     *     }
    1.39 +     *   }
    1.40 +     *
    1.41       * @param tree  The try statement to inspect.
    1.42 -     * @return      An ARM block, or the original try block if there are no
    1.43 -     *              resources to manage.
    1.44 +     * @return A a desugared try-with-resources tree, or the original
    1.45 +     * try block if there are no resources to manage.
    1.46       */
    1.47 -    JCTree makeArmTry(JCTry tree) {
    1.48 +    JCTree makeTwrTry(JCTry tree) {
    1.49          make_at(tree.pos());
    1.50          twrVars = twrVars.dup();
    1.51 -        JCBlock armBlock = makeArmBlock(tree.resources, tree.body, 0);
    1.52 +        JCBlock twrBlock = makeTwrBlock(tree.resources, tree.body, 0);
    1.53          if (tree.catchers.isEmpty() && tree.finalizer == null)
    1.54 -            result = translate(armBlock);
    1.55 +            result = translate(twrBlock);
    1.56          else
    1.57 -            result = translate(make.Try(armBlock, tree.catchers, tree.finalizer));
    1.58 +            result = translate(make.Try(twrBlock, tree.catchers, tree.finalizer));
    1.59          twrVars = twrVars.leave();
    1.60          return result;
    1.61      }
    1.62  
    1.63 -    private JCBlock makeArmBlock(List<JCTree> resources, JCBlock block, int depth) {
    1.64 +    private JCBlock makeTwrBlock(List<JCTree> resources, JCBlock block, int depth) {
    1.65          if (resources.isEmpty())
    1.66              return block;
    1.67  
    1.68 @@ -1497,16 +1527,16 @@
    1.69  
    1.70          int oldPos = make.pos;
    1.71          make.at(TreeInfo.endPos(block));
    1.72 -        JCBlock finallyClause = makeArmFinallyClause(primaryException, expr);
    1.73 +        JCBlock finallyClause = makeTwrFinallyClause(primaryException, expr);
    1.74          make.at(oldPos);
    1.75 -        JCTry outerTry = make.Try(makeArmBlock(resources.tail, block, depth + 1),
    1.76 +        JCTry outerTry = make.Try(makeTwrBlock(resources.tail, block, depth + 1),
    1.77                                    List.<JCCatch>of(catchClause),
    1.78                                    finallyClause);
    1.79          stats.add(outerTry);
    1.80          return make.Block(0L, stats.toList());
    1.81      }
    1.82  
    1.83 -    private JCBlock makeArmFinallyClause(Symbol primaryException, JCExpression resource) {
    1.84 +    private JCBlock makeTwrFinallyClause(Symbol primaryException, JCExpression resource) {
    1.85          // primaryException.addSuppressed(catchException);
    1.86          VarSymbol catchException =
    1.87              new VarSymbol(0, make.paramName(2),
    1.88 @@ -1525,22 +1555,30 @@
    1.89          List<JCCatch> catchClauses = List.<JCCatch>of(make.Catch(catchExceptionDecl, catchBlock));
    1.90          JCTry tryTree = make.Try(tryBlock, catchClauses, null);
    1.91  
    1.92 -        // if (resource != null) resourceClose;
    1.93 -        JCExpression nullCheck = makeBinary(JCTree.NE,
    1.94 -                                            make.Ident(primaryException),
    1.95 -                                            makeNull());
    1.96 -        JCIf closeIfStatement = make.If(nullCheck,
    1.97 +        // if (primaryException != null) {try...} else resourceClose;
    1.98 +        JCIf closeIfStatement = make.If(makeNonNullCheck(make.Ident(primaryException)),
    1.99                                          tryTree,
   1.100                                          makeResourceCloseInvocation(resource));
   1.101 -        return make.Block(0L, List.<JCStatement>of(closeIfStatement));
   1.102 +
   1.103 +        // if (#resource != null) { if (primaryException ...  }
   1.104 +        return make.Block(0L,
   1.105 +                          List.<JCStatement>of(make.If(makeNonNullCheck(resource),
   1.106 +                                                       closeIfStatement,
   1.107 +                                                       null)));
   1.108      }
   1.109  
   1.110      private JCStatement makeResourceCloseInvocation(JCExpression resource) {
   1.111          // create resource.close() method invocation
   1.112 -        JCExpression resourceClose = makeCall(resource, names.close, List.<JCExpression>nil());
   1.113 +        JCExpression resourceClose = makeCall(resource,
   1.114 +                                              names.close,
   1.115 +                                              List.<JCExpression>nil());
   1.116          return make.Exec(resourceClose);
   1.117      }
   1.118  
   1.119 +    private JCExpression makeNonNullCheck(JCExpression expression) {
   1.120 +        return makeBinary(JCTree.NE, expression, makeNull());
   1.121 +    }
   1.122 +
   1.123      /** Construct a tree that represents the outer instance
   1.124       *  <C.this>. Never pick the current `this'.
   1.125       *  @param pos           The source code position to be used for the tree.
   1.126 @@ -3573,7 +3611,7 @@
   1.127          if (tree.resources.isEmpty()) {
   1.128              super.visitTry(tree);
   1.129          } else {
   1.130 -            result = makeArmTry(tree);
   1.131 +            result = makeTwrTry(tree);
   1.132          }
   1.133      }
   1.134  

     2.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     2.2 +++ b/test/tools/javac/TryWithResources/TwrNullTests.java	Fri Feb 18 15:55:20 2011 -0800
     2.3 @@ -0,0 +1,72 @@
     2.4 +/*
     2.5 + * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
     2.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     2.7 + *
     2.8 + * This code is free software; you can redistribute it and/or modify it
     2.9 + * under the terms of the GNU General Public License version 2 only, as
    2.10 + * published by the Free Software Foundation.
    2.11 + *
    2.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
    2.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    2.14 + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    2.15 + * version 2 for more details (a copy is included in the LICENSE file that
    2.16 + * accompanied this code).
    2.17 + *
    2.18 + * You should have received a copy of the GNU General Public License version
    2.19 + * 2 along with this work; if not, write to the Free Software Foundation,
    2.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    2.21 + *
    2.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    2.23 + * or visit www.oracle.com if you need additional information or have any
    2.24 + * questions.
    2.25 + */
    2.26 +
    2.27 +/*
    2.28 + * @test
    2.29 + * @bug 7020047
    2.30 + * @summary Test null handling of try-with-resources statement
    2.31 + */
    2.32 +
    2.33 +public class TwrNullTests {
    2.34 +    /*
    2.35 +     * Each try-with-resources statement generates two calls to the
    2.36 +     * close method for each resource: one for when there is a primary
    2.37 +     * exception present and the second for when a primary exception
    2.38 +     * is absent.  The null handling of both cases needs to be
    2.39 +     * checked.
    2.40 +     */
    2.41 +    public static void main(String... args) {
    2.42 +        testNormalCompletion();
    2.43 +        testNoSuppression();
    2.44 +    }
    2.45 +
    2.46 +    /*
    2.47 +     * Verify empty try-with-resources on a null resource completes
    2.48 +     * normally; no NPE from the generated close call.
    2.49 +     */
    2.50 +    private static void testNormalCompletion() {
    2.51 +        try(AutoCloseable resource = null) {
    2.52 +            return; // Nothing to see here, move along.
    2.53 +        } catch (Exception e) {
    2.54 +            throw new AssertionError("Should not be reached", e);
    2.55 +        }
    2.56 +    }
    2.57 +
    2.58 +    /*
    2.59 +     * Verify that a NPE on a null resource is <em>not</em> added as a
    2.60 +     * suppressed exception to an exception from try block.
    2.61 +     */
    2.62 +    private static void testNoSuppression() {
    2.63 +        try(AutoCloseable resource = null) {
    2.64 +            throw new java.io.IOException();
    2.65 +        } catch(java.io.IOException ioe) {
    2.66 +            Throwable[] suppressed = ioe.getSuppressed();
    2.67 +            if (suppressed.length != 0) {
    2.68 +                throw new AssertionError("Non-empty suppressed exceptions",
    2.69 +                                         ioe);
    2.70 +            }
    2.71 +        } catch (Exception e) {
    2.72 +            throw new AssertionError("Should not be reached", e);
    2.73 +        }
    2.74 +    }
    2.75 +}