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Avoid unnecessary arrayCopy in Kit.readStream #1033

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merged 2 commits into from
Sep 29, 2021
+141 −108
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Avoid unnecessary arrayCopy in Kit.readStream #1033

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Avoid unnecessary arrayCopy in Kit.readStream, when initialBufferCapa…
rPraml Sep 20, 2021
85eb05a
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rPraml Sep 20, 2021
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191 changes: 83 additions & 108 deletions src/org/mozilla/javascript/Kit.java
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Original file line number Diff line number Diff line change
Expand Up @@ -12,32 +12,23 @@
import java.io.Reader;
import java.util.Map;

/**
* Collection of utilities
*/

public class Kit
{
public static Class<?> classOrNull(String className)
{
/** Collection of utilities */
public class Kit {
public static Class<?> classOrNull(String className) {
try {
return Class.forName(className);
} catch (ClassNotFoundException ex) {
} catch (SecurityException ex) {
} catch (LinkageError ex) {
} catch (ClassNotFoundException ex) {
} catch (SecurityException ex) {
} catch (LinkageError ex) {
} catch (IllegalArgumentException e) {
// Can be thrown if name has characters that a class name
// can not contain
}
return null;
}

/**
* Attempt to load the class of the given name. Note that the type parameter
* isn't checked.
*/
public static Class<?> classOrNull(ClassLoader loader, String className)
{
/** Attempt to load the class of the given name. Note that the type parameter isn't checked. */
public static Class<?> classOrNull(ClassLoader loader, String className) {
try {
return loader.loadClass(className);
} catch (ClassNotFoundException ex) {
Expand All @@ -50,23 +41,19 @@ public static Class<?> classOrNull(ClassLoader loader, String className)
return null;
}

static Object newInstanceOrNull(Class<?> cl)
{
static Object newInstanceOrNull(Class<?> cl) {
try {
return cl.newInstance();
} catch (SecurityException x) {
} catch (LinkageError ex) {
} catch (LinkageError ex) {
} catch (InstantiationException x) {
} catch (IllegalAccessException x) {
}
return null;
}

/**
* Check that testClass is accessible from the given loader.
*/
static boolean testIfCanLoadRhinoClasses(ClassLoader loader)
{
/** Check that testClass is accessible from the given loader. */
static boolean testIfCanLoadRhinoClasses(ClassLoader loader) {
Class<?> testClass = ScriptRuntime.ContextFactoryClass;
Class<?> x = Kit.classOrNull(loader, testClass.getName());
if (x != testClass) {
Expand All @@ -80,17 +67,18 @@ static boolean testIfCanLoadRhinoClasses(ClassLoader loader)
}

/**
* If character <code>c</code> is a hexadecimal digit, return
* <code>accumulator</code> * 16 plus corresponding
* number. Otherise return -1.
* If character <code>c</code> is a hexadecimal digit, return <code>accumulator</code> * 16 plus
* corresponding number. Otherise return -1.
*/
public static int xDigitToInt(int c, int accumulator)
{
check: {
public static int xDigitToInt(int c, int accumulator) {
check:
{
// Use 0..9 < A..Z < a..z
if (c <= '9') {
c -= '0';
if (0 <= c) { break check; }
if (0 <= c) {
break check;
}
} else if (c <= 'F') {
if ('A' <= c) {
c -= ('A' - 10);
Expand All @@ -108,12 +96,12 @@ public static int xDigitToInt(int c, int accumulator)
}

/**
* Add <i>listener</i> to <i>bag</i> of listeners.
* The function does not modify <i>bag</i> and return a new collection
* containing <i>listener</i> and all listeners from <i>bag</i>.
* Bag without listeners always represented as the null value.
* <p>
* Usage example:
* Add <i>listener</i> to <i>bag</i> of listeners. The function does not modify <i>bag</i> and
* return a new collection containing <i>listener</i> and all listeners from <i>bag</i>. Bag
* without listeners always represented as the null value.
*
* <p>Usage example:
*
* <pre>
* private volatile Object changeListeners;
*
Expand Down Expand Up @@ -150,22 +138,20 @@ public static int xDigitToInt(int c, int accumulator)
*
* @param listener Listener to add to <i>bag</i>
* @param bag Current collection of listeners.
* @return A new bag containing all listeners from <i>bag</i> and
* <i>listener</i>.
* @return A new bag containing all listeners from <i>bag</i> and <i>listener</i>.
* @see #removeListener(Object bag, Object listener)
* @see #getListener(Object bag, int index)
*/
public static Object addListener(Object bag, Object listener)
{
public static Object addListener(Object bag, Object listener) {
if (listener == null) throw new IllegalArgumentException();
if (listener instanceof Object[]) throw new IllegalArgumentException();

if (bag == null) {
bag = listener;
} else if (!(bag instanceof Object[])) {
bag = new Object[] { bag, listener };
bag = new Object[] {bag, listener};
} else {
Object[] array = (Object[])bag;
Object[] array = (Object[]) bag;
int L = array.length;
// bag has at least 2 elements if it is array
if (L < 2) throw new IllegalArgumentException();
Expand All @@ -179,30 +165,26 @@ public static Object addListener(Object bag, Object listener)
}

/**
* Remove <i>listener</i> from <i>bag</i> of listeners.
* The function does not modify <i>bag</i> and return a new collection
* containing all listeners from <i>bag</i> except <i>listener</i>.
* If <i>bag</i> does not contain <i>listener</i>, the function returns
* <i>bag</i>.
* <p>
* For usage example, see {@link #addListener(Object bag, Object listener)}.
* Remove <i>listener</i> from <i>bag</i> of listeners. The function does not modify <i>bag</i>
* and return a new collection containing all listeners from <i>bag</i> except <i>listener</i>.
* If <i>bag</i> does not contain <i>listener</i>, the function returns <i>bag</i>.
*
* <p>For usage example, see {@link #addListener(Object bag, Object listener)}.
*
* @param listener Listener to remove from <i>bag</i>
* @param bag Current collection of listeners.
* @return A new bag containing all listeners from <i>bag</i> except
* <i>listener</i>.
* @return A new bag containing all listeners from <i>bag</i> except <i>listener</i>.
* @see #addListener(Object bag, Object listener)
* @see #getListener(Object bag, int index)
*/
public static Object removeListener(Object bag, Object listener)
{
public static Object removeListener(Object bag, Object listener) {
if (listener == null) throw new IllegalArgumentException();
if (listener instanceof Object[]) throw new IllegalArgumentException();

if (bag == listener) {
bag = null;
} else if (bag instanceof Object[]) {
Object[] array = (Object[])bag;
Object[] array = (Object[]) bag;
int L = array.length;
// bag has at least 2 elements if it is array
if (L < 2) throw new IllegalArgumentException();
Expand Down Expand Up @@ -231,25 +213,22 @@ public static Object removeListener(Object bag, Object listener)
}

/**
* Get listener at <i>index</i> position in <i>bag</i> or null if
* <i>index</i> equals to number of listeners in <i>bag</i>.
* <p>
* For usage example, see {@link #addListener(Object bag, Object listener)}.
* Get listener at <i>index</i> position in <i>bag</i> or null if <i>index</i> equals to number
* of listeners in <i>bag</i>.
*
* <p>For usage example, see {@link #addListener(Object bag, Object listener)}.
*
* @param bag Current collection of listeners.
* @param index Index of the listener to access.
* @return Listener at the given index or null.
* @see #addListener(Object bag, Object listener)
* @see #removeListener(Object bag, Object listener)
*/
public static Object getListener(Object bag, int index)
{
public static Object getListener(Object bag, int index) {
if (index == 0) {
if (bag == null)
return null;
if (!(bag instanceof Object[]))
return bag;
Object[] array = (Object[])bag;
if (bag == null) return null;
if (!(bag instanceof Object[])) return bag;
Object[] array = (Object[]) bag;
// bag has at least 2 elements if it is array
if (array.length < 2) throw new IllegalArgumentException();
return array[0];
Expand All @@ -258,22 +237,20 @@ public static Object getListener(Object bag, int index)
if (bag == null) throw new IllegalArgumentException();
return null;
}
Object[] array = (Object[])bag;
Object[] array = (Object[]) bag;
// the array access will check for index on its own
return array[1];
} else {
// bag has to array
Object[] array = (Object[])bag;
Object[] array = (Object[]) bag;
int L = array.length;
if (L < 2) throw new IllegalArgumentException();
if (index == L)
return null;
if (index == L) return null;
return array[index];
}
}

static Object initHash(Map<Object,Object> h, Object key, Object initialValue)
{
static Object initHash(Map<Object, Object> h, Object key, Object initialValue) {
synchronized (h) {
Object current = h.get(key);
if (current == null) {
Expand All @@ -285,46 +262,39 @@ static Object initHash(Map<Object,Object> h, Object key, Object initialValue)
return initialValue;
}

private final static class ComplexKey
{
private static final class ComplexKey {
private Object key1;
private Object key2;
private int hash;

ComplexKey(Object key1, Object key2)
{
ComplexKey(Object key1, Object key2) {
this.key1 = key1;
this.key2 = key2;
}

@Override
public boolean equals(Object anotherObj)
{
if (!(anotherObj instanceof ComplexKey))
return false;
ComplexKey another = (ComplexKey)anotherObj;
public boolean equals(Object anotherObj) {
if (!(anotherObj instanceof ComplexKey)) return false;
ComplexKey another = (ComplexKey) anotherObj;
return key1.equals(another.key1) && key2.equals(another.key2);
}

@Override
public int hashCode()
{
public int hashCode() {
if (hash == 0) {
hash = key1.hashCode() ^ key2.hashCode();
}
return hash;
}
}

public static Object makeHashKeyFromPair(Object key1, Object key2)
{
public static Object makeHashKeyFromPair(Object key1, Object key2) {
if (key1 == null) throw new IllegalArgumentException();
if (key2 == null) throw new IllegalArgumentException();
return new ComplexKey(key1, key2);
}

public static String readReader(Reader reader) throws IOException
{
public static String readReader(Reader reader) throws IOException {
try (BufferedReader in = new BufferedReader(reader)) {
char[] cbuf = new char[1024];
StringBuilder sb = new StringBuilder(1024);
Expand All @@ -336,23 +306,34 @@ public static String readReader(Reader reader) throws IOException
}
}

public static byte[] readStream(InputStream is, int initialBufferCapacity)
throws IOException
{
public static byte[] readStream(InputStream is, int initialBufferCapacity) throws IOException {
if (initialBufferCapacity <= 0) {
throw new IllegalArgumentException(
"Bad initialBufferCapacity: "+initialBufferCapacity);
"Bad initialBufferCapacity: " + initialBufferCapacity);
}
byte[] buffer = new byte[initialBufferCapacity];
int cursor = 0;
for (;;) {
for (; ; ) {
int n = is.read(buffer, cursor, buffer.length - cursor);
if (n < 0) { break; }
if (n < 0) {
break;
}
cursor += n;
if (cursor == buffer.length) {
int readahead = -1;
if (cursor == initialBufferCapacity) {
readahead = is.read();
if (readahead < 0) { // Check for EOS
return buffer;
}
}
byte[] tmp = new byte[buffer.length * 2];
System.arraycopy(buffer, 0, tmp, 0, cursor);
buffer = tmp;
if (readahead != -1) {
buffer[cursor++] = (byte) readahead;
readahead = -1;
}
}
}
if (cursor != buffer.length) {
Expand All @@ -364,29 +345,23 @@ public static byte[] readStream(InputStream is, int initialBufferCapacity)
}

/**
* Throws RuntimeException to indicate failed assertion.
* The function never returns and its return type is RuntimeException
* only to be able to write <code>throw Kit.codeBug()</code> if plain
* <code>Kit.codeBug()</code> triggers unreachable code error.
* Throws RuntimeException to indicate failed assertion. The function never returns and its
* return type is RuntimeException only to be able to write <code>throw Kit.codeBug()</code> if
* plain <code>Kit.codeBug()</code> triggers unreachable code error.
*/
public static RuntimeException codeBug()
throws RuntimeException
{
public static RuntimeException codeBug() throws RuntimeException {
RuntimeException ex = new IllegalStateException("FAILED ASSERTION");
// Print stack trace ASAP
ex.printStackTrace(System.err);
throw ex;
}

/**
* Throws RuntimeException to indicate failed assertion.
* The function never returns and its return type is RuntimeException
* only to be able to write <code>throw Kit.codeBug()</code> if plain
* <code>Kit.codeBug()</code> triggers unreachable code error.
* Throws RuntimeException to indicate failed assertion. The function never returns and its
* return type is RuntimeException only to be able to write <code>throw Kit.codeBug()</code> if
* plain <code>Kit.codeBug()</code> triggers unreachable code error.
*/
public static RuntimeException codeBug(String msg)
throws RuntimeException
{
public static RuntimeException codeBug(String msg) throws RuntimeException {
msg = "FAILED ASSERTION: " + msg;
RuntimeException ex = new IllegalStateException(msg);
// Print stack trace ASAP
Expand Down
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