Class TryWithResourcesJavacFilter.Matcher

java.lang.Object

org.jacoco.core.internal.analysis.filter.AbstractMatcher

org.jacoco.core.internal.analysis.filter.TryWithResourcesJavacFilter.Matcher

Enclosing class:

TryWithResourcesJavacFilter

static class TryWithResourcesJavacFilter.Matcher
extends AbstractMatcher

javac from JDK 7 and 8 generates bytecode that is equivalent to the compilation of source code that is described in JLS 14.20.3. try-with-resources:

    Resource r = ...;
    Throwable primaryExc = null;
    try {
        ...
    } finally {
        if (r != null) {
            if (primaryExc != null) {
                try {
                    r.close();
                } catch (Throwable suppressedExc) {
                    primaryExc.addSuppressed(suppressedExc);
                }
            } else {
                r.close();
            }
        }
    }

Case of multiple resources looks like multiple nested try-with-resources statements. javac from JDK 9 EA b160 does the same, but with some optimizations (see JDK-7020499):

• null check for resource is omitted when it is initialized using new
• synthetic method $closeResource containing null check of primaryExc and calls to methods addSuppressed and close is used when number of copies of closing logic reaches threshold, null check of resource (if present) is done before call of this method

During matching association between resource and slot of variable is done on exceptional path and is used to find close of resource on normal path. Order of loading variables primaryExc and r is different in different cases, which implies that this order should be determined before association. So TryWithResourcesJavacFilter.Matcher.JavacPattern defines all possible variants that will be tried sequentially.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static enum	TryWithResourcesJavacFilter.Matcher.JavacPattern

Field Summary

Fields

Modifier and Type	Field	Description
private String	expectedOwner
private final IFilterOutput	output
private org.objectweb.asm.tree.AbstractInsnNode	start

Fields inherited from class AbstractMatcher

cursor, vars

Constructor Summary

Constructors

Constructor	Description
Matcher(IFilterOutput output)

Method Summary

Modifier and Type	Method	Description
private boolean	matchJavac(TryWithResourcesJavacFilter.Matcher.JavacPattern p)
private void	nextIsClose()
private boolean	nextIsJavacClose(TryWithResourcesJavacFilter.Matcher.JavacPattern p, String ctx)	On a first invocation will associate variables with names "r" and "primaryExc", on subsequent invocations will use those associations for checks.
private void	start(org.objectweb.asm.tree.AbstractInsnNode start)

Methods inherited from class AbstractMatcher

firstIsALoad0, next, nextIs, nextIsField, nextIsInvoke, nextIsSwitch, nextIsType, nextIsVar, skipNonOpcodes, skipNonOpcodes

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

output

private final IFilterOutput output

expectedOwner

private String expectedOwner

start

private org.objectweb.asm.tree.AbstractInsnNode start

Constructor Details

Matcher

Matcher(IFilterOutput output)

Method Details

start

private void start(org.objectweb.asm.tree.AbstractInsnNode start)

matchJavac

private boolean matchJavac(TryWithResourcesJavacFilter.Matcher.JavacPattern p)

nextIsJavacClose

private boolean nextIsJavacClose(TryWithResourcesJavacFilter.Matcher.JavacPattern p,
 String ctx)

On a first invocation will associate variables with names "r" and "primaryExc", on subsequent invocations will use those associations for checks.

nextIsClose

private void nextIsClose()