implement the jsdIContext interface.
create only one jsdValue wrapper per unique jsval.
add executionContext property to jsdIStackFrame.
add enumerateContexts to jsdIDebuggerService.
add jsdIContextEnumerator interface.
adds jsdIDebugHook interface, change the meaning of jsdIErrorHook.
error hook is called when an error occurs, and is given information about the error report.
debug hook is called when/if the error hook returns false, and is given information about the ececution state.
Thanks!
As promised, I tried the debugger this afternoon and I had a problem with the '-f' option.
We use -f to run a standard "startup" script before executing the "main" script. For
example, we run the Rhino shell with the options "-f startup.js main.js".
When running the debugger's shell with the same options the debugger exits after the
startup.js completes; i.e., I can single step starting from startup.js but the debugger
exits at the end of startup.js without letting me single step into main.js. This worked
fine in the 1.5R2 release of Rhino and the debugger.
I have not had a chance to look into the problem closely, but a cursory look at the code
suggests (to me) that the problem can be in either the debugger or the shell (since the
debugger basically runs the shell after creating the right "hooks".) Of course, it could
also be a problem with my embedding.
So ... my question is, has anyone tried single stepping when the options to the debugger
include a '-f' option. If so, I'll continue to look for a problem in my embedding.
Any suggestions would be appreciated.
Thanks,
dave
Norris,
I realize this is probably a nuisance, but the following problem causes our
regression test suite to fail:
js> foo = new Error("bar")
undefined: bar
js> foo.name Error
js> foo.toString()
undefined: bar
Our test suite expects:
js> foo = new Error("bar")
Error: bar
js> foo.name Error
js> foo.toString()
Error: bar
I have not yet tried the debugger with the RC2 release, but I expect to get
to that later today.
I hope I'm not to late to influence the 1.5R3 release.
Thanks,
dave
understand exactly what the problem is here, and it does not seem to
happen on gcc 2.96, and 2.95 doesn't have the alias optimizations that
called for the new code in the first place, just make 2.95 use the old
code. r=timeless, sr=brendan.
We have found a problem in string.replace() when replacing a regular
expression with a dollar sign. The following code works right when the
replacement string does not contain "$":
$ java -jar js.jar
js> var re = new RegExp("%%%");
js> var price = "%%% 1.99";
js> price.replace(re, "USD");
USD 1.99
js> price.replace(re, "$");
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException
at
org.mozilla.javascript.regexp.ReplaceData.interpretDollar(RegExpImpl.java:40 0)
at
org.mozilla.javascript.regexp.ReplaceData.findReplen(RegExpImpl.java:502)
at
org.mozilla.javascript.regexp.RegExpImpl.replace(RegExpImpl.java:116)
at
org.mozilla.javascript.NativeString.execMethod(NativeString.java:266)
at org.mozilla.javascript.IdFunction.call(IdFunction.java:78)
at org.mozilla.javascript.ScriptRuntime.call(ScriptRuntime.java:1222)
at org.mozilla.javascript.Interpreter.interpret(Interpreter.java:1940)
at
org.mozilla.javascript.InterpretedScript.call(InterpretedScript.java:68)
at
org.mozilla.javascript.InterpretedScript.exec(InterpretedScript.java:59)
at org.mozilla.javascript.Context.evaluateReader(Context.java:773)
at
org.mozilla.javascript.tools.shell.Main.evaluateReader(Main.java:312)
at
org.mozilla.javascript.tools.shell.Main.processSource(Main.java:219)
at org.mozilla.javascript.tools.shell.Main.exec(Main.java:106)
at org.mozilla.javascript.tools.shell.Main.main(Main.java:68)
We are converting from spidermonkey to rhino and it appears that the
name property for the constructor function returns "constructor" for
all builtin types. Spidermonkey would return "Date" or "Array" or
whatever. Is there a workaround? This code needs to work with both
interpreters.
Here is an example of the rhino behavior:
js> var i=new Date;
js> i.constructor.name
constructor
js> Date.name
constructor
js> function bob(){}
js> bob.name
bob
js> var i = new Array();
js> i.constructor.name
constructor
js>
a) create a new nsIComponentManager with only four functions on it:
CreateInstance CreateInstanceByContractID GetClassInfo GetClassInfoByContractID.
b) rename the old nsIComponentManager to nsIComponentManagerObsolete.
c) fixes callers which use to access the nsIComponentManager for component
registration functionality. These callers will temporary use the
nsIComponentManagerObsolete interface.
d) Create a new API NS_GetComponentManager() which mirrors the
NS_GetServiceManager()
e) Perserves the old NS_GetGlobalComponentManager(). Note the cast usage.
r/sr = rpotts@netscape.comalecf@netscape.combrendan@mozilla.org
* Adds Makefile.ins to win32 specific dirs
* Adds WINNT ifdefs to Makefile.ins
* Causes NSPR to be compiled with --with-mozilla
* Misc general Makefile.in cleanup
Bug #58981 r=mcafee
I'm the maintainer of JPackage project rhino package (see
jpackage.sourceforge.net). I just found two problems for building it (version
1.52 from cvs):
- the property src.debugger is badly initialised in toolsrc/build.xml. See
patch attached for correction. Moreover, this was a real pain to make offline
building possible. I guess it's a licensing problem that prevents you
including those files in rhino sources ?
- the produced javadoc has an empty (0 sized) package-list file. Have you got
any idea why ?
-- Guillaume Rousse <rousse@ccr.jussieu.fr>
GPG key http://lis.snv.jussieu.fr/~rousse/gpgkey.html
In our browser we need to support scripts that use as an identifier name future reserved keywords such as interface. The scripts are rather old and perfectly legal under previous revisions of EcmaScript which does not included the list of almost every Java keyword to the future reserve.
To support this I added an option to query Context.hasFeature for FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER:
/**
* if hasFeature(RESERVED_KEYWORD_AS_IDENTIFIER) returns true,
* treat future reserved keyword (see Ecma-262, section 7.5.3) as ordinary
* identifiers but warn about this usage
*/
public static final int FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER = 3;
The corresponding code in TokenStream checks for it and issues just a warning when this feature is enabled.
I also think that it would be better not to return RESERVED as a token from TokenStream.getToken but report the specific syntax error immediately because it is very unclear from the error message:
js> x.interface = 1
js: "<stdin>", line 1: uncaught JavaScript exception: SyntaxError: missing name after . operator (<stdin>; line 1)
js: x.interface = 1
js: ..........^
what exactly went wrong. I can send a patch later for that.
Regards, Igor
I'm working on a project which uses rhino. I wanted to have finer
control over class generation and saving so I've done some patching
and clean up on the current rhino tip.
The biggest change I've made is the replacement of ClassOutput with
ClassRepository that has the single method:
public boolean storeClass(String className, byte[] classBytes,
boolean isTopLevel) throws IOException;
This interface allows any arbitary storage method, such as a
Hashtable/Map. In addition it also allows you to specify whether a
class should be loaded, via returning true or false. You can still use
ClassOutput as I've coded an internal wrapper.
With this interface it has also been possible to strip out the file
saving code from Codegen and OptClassNameHelper. The file
saving code is now an inner class FileClassRepository in Context. As
a consequence of this I've stripped out some methods from ClassNameHelper.
The resulting code is much more cleaner then before hand and everything
still works as per usual.
Other small additions are:
o Annonymous functions are now named class$1 instead of class1
o get/setClassName added to ClassNameHelper exposed in Context.
My final thoughts are, since all methods in ClassNameHelper except reset()
are now exposed whould n't it be much more "cleaner" to simply to some
how work around to eliminate reset() and provide getClassNameHelper()
via Context? You could then remove the numerous ClassNameHelper shadow
methods from Context.
Likewise, FileClassRepository could be made a public class very easily
and combined with the above result in a dozen or so less public methods in
Context.
Anyway, the changes can be found on http://www.cins.co.uk/rhino.zip
Hope it is of use to some
Kemal Bayram
I'm working on a project which uses rhino. I wanted to have finer
control over class generation and saving so I've done some patching
and clean up on the current rhino tip.
The biggest change I've made is the replacement of ClassOutput with
ClassRepository that has the single method:
public boolean storeClass(String className, byte[] classBytes,
boolean isTopLevel) throws IOException;
This interface allows any arbitary storage method, such as a
Hashtable/Map. In addition it also allows you to specify whether a
class should be loaded, via returning true or false. You can still use
ClassOutput as I've coded an internal wrapper.
With this interface it has also been possible to strip out the file
saving code from Codegen and OptClassNameHelper. The file
saving code is now an inner class FileClassRepository in Context. As
a consequence of this I've stripped out some methods from ClassNameHelper.
The resulting code is much more cleaner then before hand and everything
still works as per usual.
Other small additions are:
o Annonymous functions are now named class$1 instead of class1
o get/setClassName added to ClassNameHelper exposed in Context.
My final thoughts are, since all methods in ClassNameHelper except reset()
are now exposed whould n't it be much more "cleaner" to simply to some
how work around to eliminate reset() and provide getClassNameHelper()
via Context? You could then remove the numerous ClassNameHelper shadow
methods from Context.
Likewise, FileClassRepository could be made a public class very easily
and combined with the above result in a dozen or so less public methods in
Context.
Anyway, the changes can be found on http://www.cins.co.uk/rhino.zip
Hope it is of use to some
Kemal Bayram <rhino@cins.co.uk>
I suggest to move the code in ScriptableObject.get/put that deals with getter/setter
into separated methods so it would be easy to follow the code and the attached patch
does just that.
The following test case case leads to a compilation error in Rhino. In this
script alert is an user defined
function in the global object and it shows the value of the specified
parameter in a popup window. Save the script as a html file and run it under
Netscape and IE. The output via their JS engines is that alert(1)
executes but the execution of line fails as blks variable is undefined. The
Fix bug:
Rhino engine fails at compilation time itself and cannot excute the script.
It doesn't like the syntax of line.
Steven
/// **************** test case ************** ///
<script>
alert(1);
blks[ 10 << 2 ] |= true;
alert(2);
</script>
/// ********************** Error Message ************************** ////
evaluating script: null
java.lang.NullPointerException
at org.mozilla.javascript.Interpreter.generateICode(Compiled Code)
at org.mozilla.javascript.Interpreter.generateICode(Compiled Code)
at org.mozilla.javascript.Interpreter.generateICode(Compiled Code)
at org.mozilla.javascript.Interpreter.generateICode(Compiled Code)
at org.mozilla.javascript.Interpreter.generateICode(Compiled Code)
at org.mozilla.javascript.Interpreter.generateICodeFromTree(Compiled Code)
at
org.mozilla.javascript.Interpreter.generateScriptICode(Interpreter.java)
at org.mozilla.javascript.Interpreter.compile(Interpreter.java)
at org.mozilla.javascript.Context.compile(Context.java)
at org.mozilla.javascript.Context.compile(Context.java)
large addition to the jsd_xpc component allows arbitrary filtering of debug hooks by url pattern, line range, and global object. also adds ability to begin instrumenting jsscripts at app startup.
I must admit this is very subtitle, but still...
Here are the lines from
public void defineProperty(String propertyName, Object delegateTo,
Method getter, Method setter, int attributes)
GetterSlot slot = (GetterSlot)getSlotToSet(propertyName,
propertyName.hashCode(),
true);
slot.delegateTo = delegateTo;
slot.getter = getter;
slot.setter = setter;
slot.setterReturnsValue = setter != null && setter.getReturnType() != Void.TYPE;
slot.value = null;
slot.attributes = (short) attributes;
slot.flags = (byte)flags;
Now suppose that after the new slot is added, another thread is accessing it. Then it would see not yet ready slot with all nasty consequences! For example, SMP computer can re-arrange writes so the new value of slot.flags would be visible before slot.getter then another thread would generate null pointer exception.
race2_fix.diff fixes that by using the explicit Slot argument to addSlot instead of boolean flag so the new slot can be fully initialized and then inserted under synchronization to the table. I also call addSlot directly because it is supposed to be used with not-yet existed properties and split addSlot to addSlot and addSlotImpl so in case of table growth there is no need to re-enter already synchronized monitor.
This changes also allows to explicitly throw RuntimeException if defineProperty is called for the property that is already exists instead of either throwing cast exception in "GetterSlot slot = (GetterSlot)getSlotToSet(propertyName," or worth yet re-initializing already existed slot.
Regards, Igor
Unsynchronized ScriptableObject.getSlotToSet contains references/modifications
to the slots array which is no go under multithreading. The attached patch
replaces references to slots by references to its local copy and moves code
to allocate the initial array to synchronized addSlot.
The patch also replace throwing of RuntimeException in case of broken code by
if (Context.check && badCondition) Context.codeBug();
Regards, Igor
also has a significant regression introduced in it. The default compiler
not only works, but also is noticably faster. Ant takes care of the
selection of the compiler automatically based on the JDK level, so the
following patch should make things better all around.
Patch from Igor:
The 2 attached patches allow to avoid wrapping of array indexes to Double object
when Interpreter knows that the index is an integer number. It speed up array
benchmark by 5-10%
array_access.diff adds to ScriptRuntime getStrIdElem and setStrIdElem to get/set
properties which known to be strings plus it modifies NativeArray to use these methods.
interpreter.diff contains the Interpreter modifications to call get/setElem for
integer or string properties when the property type is known for sure.
errors, etc.''):
We now ReportStatementTooLarge only if
- a jump offset overflows 32 bits, signed;
- there are 2**32 or more span dependencies in a script;
- a backpatch chain link is more than (2**30 - 1) bytecodes long;
- a source note's distance from the last note, or from script main entry
point, is > 0x7fffff bytes.
Narrative of the patch, by file:
- js.c
The js_SrcNoteName array of const char * is now a js_SrcNoteSpec array of
"specifiers", structs that include a const char *name member. Also, due to
span-dependent jumps at the ends of basic blocks where the decompiler knows
the basic block length, but not the jump format, we need an offset operand
for SRC_COND, SRC_IF_ELSE, and SRC_WHILE (to tell the distance from the
branch bytecode after the condition expression to the span-dependent jump).
- jsarena.[ch]
JS arenas are used mainly for last-in-first-out allocation with _en masse_
release to the malloc pool (or, optionally, to a private freelist). But
the code generator needs to allocate and grow (by doubling, to avoid O(n^2)
growth) allocations that hold bytecode, source notes, and span-dependency
records. This exception to LIFO allocation works by claiming an entire
arena from the pool and realloc'ing it, as soon as the allocation size
reaches the pool's default arena size. Call such an allocation a "large
single allocation".
This patch adds a new arena API, JS_ArenaFreeAllocation, which can be used
to free a large single allocation. If called with an allocation that's not
a large single allocation, it will nevertheless attempt to retract the arena
containing that allocation, if the allocation is last within its arena.
Thus JS_ArenaFreeAllocation adds a non-LIFO "free" special case to match the
non-LIFO "grow" special case already implemented under JS_ARENA_GROW for
large single allocations.
The code generator still benefits via this extension to arenas, over purely
manual malloc/realloc/free, by virtue of _en masse_ free (JS_ARENA_RELEASE
after code generation has completed, successfully or not).
To avoid searching for the previous arena, in order to update its next
member upon reallocation of the arena containing a large single allocation,
the oversized arena has a back-pointer to that next member stored (but not
as allocable space within the arena) in a (JSArena **) footer at its end.
- jscntxt.c
I've observed for many scripts that the bytes of source notes and bytecode
are of comparable lengths, but only now am I fixing the default arena size
for cx->notePool to match the size for cx->codePool (1024 instead of 256).
- jsemit.c
Span-dependent instructions in JS bytecode consist of the jump (JOF_JUMP)
and switch (JOF_LOOKUPSWITCH, JOF_TABLESWITCH) format opcodes, subdivided
into unconditional (gotos and gosubs), and conditional jumps or branches
(which pop a value, test it, and jump depending on its value). Most jumps
have just one immediate operand, a signed offset from the jump opcode's pc
to the target bytecode. The lookup and table switch opcodes may contain
many jump offsets.
This patch adds "X" counterparts to the opcodes/formats (X is suffixed, btw,
to prefer JSOP_ORX and thereby to avoid colliding on the JSOP_XOR name for
the extended form of the JSOP_OR branch opcode). The unextended or short
formats have 16-bit signed immediate offset operands, the extended or long
formats have 32-bit signed immediates. The span-dependency problem consists
of selecting as few long instructions as possible, or about as few -- since
jumps can span other jumps, extending one jump may cause another to need to
be extended.
Most JS scripts are short, so need no extended jumps. We optimize for this
case by generating short jumps until we know a long jump is needed. After
that point, we keep generating short jumps, but each jump's 16-bit immediate
offset operand is actually an unsigned index into cg->spanDeps, an array of
JSSpanDep structs. Each struct tells the top offset in the script of the
opcode, the "before" offset of the jump (which will be the same as top for
simplex jumps, but which will index further into the bytecode array for a
non-initial jump offset in a lookup or table switch), the after "offset"
adjusted during span-dependent instruction selection (initially the same
value as the "before" offset), and the jump target (more below).
Since we generate cg->spanDeps lazily, from within js_SetJumpOffset, we must
ensure that all bytecode generated so far can be inspected to discover where
the jump offset immediate operands lie within CG_CODE(cg). But the bonus is
that we generate span-dependency records sorted by their offsets, so we can
binary-search when trying to find a JSSpanDep for a given bytecode offset,
or the nearest JSSpanDep at or above a given pc.
To avoid limiting scripts to 64K jumps, if the cg->spanDeps index overflows
65534, we store SPANDEP_INDEX_HUGE in the jump's immediate operand. This
tells us that we need to binary-search for the cg->spanDeps entry by the
jump opcode's bytecode offset (sd->before).
Jump targets need to be maintained in a data structure that lets us look
up an already-known target by its address (jumps may have a common target),
and that also lets us update the addresses (script-relative, a.k.a. absolute
offsets) of targets that come after a jump target (for when a jump below
that target needs to be extended). We use an AVL tree, implemented using
recursion, but with some tricky optimizations to its height-balancing code
(see http://www.enteract.com/~bradapp/ftp/src/libs/C++/AvlTrees.html).
A final wrinkle: backpatch chains are linked by jump-to-jump offsets with
positive sign, even though they link "backward" (i.e., toward lower bytecode
address). We don't want to waste space and search time in the AVL tree for
such temporary backpatch deltas, so we use a single-bit wildcard scheme to
tag true JSJumpTarget pointers and encode untagged, signed (positive) deltas
in JSSpanDep.target pointers, depending on whether the JSSpanDep has a known
target, or is still awaiting backpatching.
Note that backpatch chains would present a problem for BuildSpanDepTable,
which inspects bytecode to build cg->spanDeps on demand, when the first
short jump offset overflows. To solve this temporary problem, we emit a
proxy bytecode (JSOP_BACKPATCH; JSOP_BACKPATCH_PUSH for jumps that push a
result on the interpreter's stack, namely JSOP_GOSUB; or JSOP_BACKPATCH_POP
for branch ops) whose nuses/ndefs counts help keep the stack balanced, but
whose opcode format distinguishes its backpatch delta immediate operand from
a normal jump offset.
The cg->spanDeps array and JSJumpTarget structs are allocated from the
cx->tempPool arena-pool. This created a LIFO vs. non-LIFO conflict: there
were two places under the TOK_SWITCH case in js_EmitTree that used tempPool
to allocate and release a chunk of memory, during whose lifetime JSSpanDep
and/or JSJumpTarget structs might also be allocated from tempPool -- the
ensuing release would prove disastrous. These bitmap and table temporaries
are now allocated from the malloc heap.
- jsinterp.c
Straightforward cloning and JUMP => JUMPX mutating of the jump and switch
format bytecode cases.
- jsobj.c
Silence warnings about %p used without (void *) casts.
- jsopcode.c
Massive and scary decompiler whackage to cope with extended jumps, using
source note offsets to help find jumps whose format (short or long) can't
be discovered from properties of prior instructions in the script.
One cute hack here: long || and && expressions are broken up to wrap before
the 80th column, with the operator at the end of each non-terminal line.
- jsopcode.h, jsopcode.tbl
The new extended jump opcodes, formats, and fundamental parameterization
macros. Also, more comments.
- jsparse.c
Random and probably only aesthetic fix to avoid decorating a foo[i]++ or
--foo[i] parse tree node with JSOP_SETCALL, wrongly (only foo(i)++ or
--foo(i), or the other post- or prefix form operator, should have such an
opcode decoration on its parse tree).
- jsscript.h
Random macro naming sanity: use trailing _ rather than leading _ for macro
local variables in order to avoid invading the standard C global namespace.
We have a tool that looks for a scary noop case of assigning an instance field
to itself. this usually comes from a constructor that assigns a argument to a
instance field with the same name and then later the argument changes name. we
ran our tool on all of our classes we have in our classpath here and found this
problem in your code.
rhino1_5R2/src/org/mozilla/javascript/regexp/NativeRegExp.java line 159 it has:
this.flags = flags;
This seems to be a bad cut and paste from the CompilerState constructor on line
2155. or has some initialization that used to work been lost?
There is a bug in JavaScriptException which prevents it from being used with
out a Rhino Context. When the getMessage() method is invoked on it, the
exception goes to the ScriptRuntime to toString the value. If you have
already exited your context, the runtime will throw an error. The solution
is to simply remove the overridden getMessage method from
JavaScriptException. JavaScriptException's constructor calls the Exception
constructor with the toString'ed value. The default implementation of
getMessage will return the exception message.
Jeff
I'm having problems getting inner class objects with Rhino.
I create a Hashmap, which is an implementation of Map. Map.Entry is an
inner interface of Map with key-value pairs. If I have a Map object,
"property", I should be able to get the key element with the expression
"property.key".
When I look at the "property" class name that Rhino returns I get:
"java.util.HashMap$Entry". I don't believe Rhino has a notion of the
inner Map.Entry object. The expression "property" succeeds. The
expression "property.key", which should retrieve the Map.Entry
keyValue(), fails with a "unexpected IllegalAccessException accessing
Java field".
I'm including a simple example that illustrates the problem. I hope you
can shed some light on this. Thanks!
Justyna
< Justyna.Horwat@Sun.com >
----
import java.io.*;
import java.util.*;
import org.mozilla.javascript.*;
public class MapTest {
public static void main(String argv[]) {
Test test = new Test();
test.testMap();
}
}
class Test {
Map map;
Set set;
Iterator it;
Map.Entry entry;
public void testMap() {
System.out.println("testMap");
map = new HashMap();
populate();
set = map.entrySet();
it = set.iterator();
// let's see if Map is populated correctly
while (it.hasNext()) {
entry = (Map.Entry) it.next();
System.out.println("entry: " + entry.getClass().getName());
System.out.println("key: " + entry.getKey());
System.out.println("value: " + entry.getValue());
}
evaluate();
}
void populate() {
map.put("firstKey", "firstValue");
map.put("secondKey", "secondValue");
map.put("thirdKey", "thirdValue");
map.put("fourthKey", "fourthValue");
}
public void evaluate() {
Context cx = Context.enter();
Scriptable scope = cx.initStandardObjects(null);
set = map.entrySet();
it = set.iterator();
while (it.hasNext()) {
entry = (Map.Entry) it.next();
scope.put("property", scope, cx.toObject(entry,scope));
}
Object eval = null;
try {
// attempt to get Map.Entry key value using Rhino
eval = cx.evaluateString(scope, "property.key", "", 0,
null);
// Unwrap scoped object
if (eval instanceof Wrapper)
eval = ((Wrapper) eval).unwrap();
} catch (JavaScriptException jse) {
System.out.println("EXCEPTION: " + jse.getMessage());
}
// DELETE
System.out.println("RHINO result: " + eval + ":");
System.out.println("RHINO class: " + eval.getClass().getName());
}
}
with JSRESOLVE_ASSIGNING, wrongly), plus a few miscellaneous bugfixes.
- Combine the JSStackFrame members constructing, special, overrides, and
reserved into a uint32 flags member.
- Separate JOF_ASSIGNING from the JOF_SET bytecode format flag, and impute
JSRESOLVE_ASSIGNING from the presence of JOF_ASSIGNING among the current
opcode's format flags. To handle the for-in loop opcodes, which do more
than simply assign -- in particular, they do property lookups whose resolve
hook outcalls should not be flagged with JSRESOLVE_ASSIGNING -- a new frame
flag, JSFRAME_ASSIGNING, has been added.
- Fix interpreter version selection to respect JS_SetVersion, whose effect on
cx->version is "sticky".
- Fix js_DecompileValueGenerator to deal with JSOP_ENUMELEM -- it never had,
as this testcase shows (it crashes without this patch):
version(120);
eval("function fe(s) { for (it[s] in this); }");
try { fe('rdonly'); } catch (e) { print(e); }
My optimization for PreorderNodeIterator has a bug that would cause an attempt
to access stack[-1] in
currentParent = (current == null) ? null : stack[stackTop - 1];
when current refers to a start node sibling. This is not visible in Rhino because
currently PreorderNodeIterator is always started from nodes with node.next == null.
iter.diff fixes that plus it removes currentParent field because it is always
available as stack[stackTop - 1] and code to access its value are executed less
frequently than the lines to update it in nextNode
Regarsd, Igor
As profiler data show, the execution time of the nextNode and replaceCurrent
methods in PreorderNodeIterator contribute quite significantly to the total
time to run Context.compileReader.
replaceCurrent is slow because it calls Node.replaceChild which have to
iterate through all previous siblings to find the nearest to the current.
But it is easy to avoid this search by caching the previous sibling of the
current while iterating over the node tree in nextNode.
nextNode slowness is attributed to the usage of java.lang.Stack which is
expensive due to its synchronized methods. In the attched patch I replaced
it by the explicit array management.
It allows to cut Context.compileReader time by 5%-30% when processing
20K-3MB sources assembled form JS files in the test suite.
