All Reflect functions specified in ECMAScript 2016 are implemented, and
most share Duktape/C helpers with their ES5 twins from Object.
* Reflect.apply()
* Reflect.construct()
* Reflect.defineProperty()
* Reflect.deleteProperty()
* Reflect.get()
* Reflect.getOwnPropertyDescriptor()
* Reflect.getPrototypeOf()
* Reflect.has()
* Reflect.isExtensible()
* Reflect.ownKeys()
* Reflect.preventExtensions()
* Reflect.set()
* Reflect.setPrototypeOf()
Presence of the Reflect object is controlled by DUK_USE_REFLECT_BUILTIN
and enabled by default in the standard configuration.
note: Reflect.enumerate() was retroactively removed in ES7, so it will
not be implemented in Duktape.
* Plain buffers still inherit from ArrayBuffer.prototype.
* Plain buffers won't object coerce, so Object(plainBuffer) fails.
* All buffer object related methods throw an error; their function bodies
are essentially empty. Note that this includes bindings such as
String.fromBuffer(), ArrayBuffer.allocPlain(), ArrayBuffer.plainOf(),
and so on. In essence, you can index plain buffers in Ecmascript but
the buffer values must be created via the C API.
* Duktape custom bindings like Duktape.dec('hex', 'deadbeef') still work
and produce plain buffers.
Change handling of plain buffers so that they behave like ArrayBuffer
instances to Ecmascript code, with limitations such as not being
extensible and all properties being virtualized. This simplifies
Ecmascript code as plain buffers are just lightweight ArrayBuffers
(similarly to how lightfuncs appear as function objects). There are
a lot of small changes in how the built-in objects and methods, and
the C API deals with plain buffer values.
Also make a few small changes to plain pointer and lightfunc handling
to improve consistency with how plain buffers are now handled.
Improve readability by doing the following renames:
* duk_hcompiledfunction -> duk_hcompfunc
* duk_hnativefunction -> duk_hnatfunc
* duk_hbufferobject -> duk_hbufobj
Corresponding renames for all caps defines.
Cast through "void *" when casting from e.g. a duk_uint8_t pointer
to a pointer with more alignment requirements (such as a struct pointer).
This is probably the best fix for cases where one also needs to do
pointer arithmetic (for which a char pointer is preferable). In cases
where pointer arithmetic is not necessarily, the original pointer could
in some cases be changed from a char pointer to a void pointer.
- Disable JSON.stringify() fastpath by default
- Rework to use DUK_USE_ALIGN_BY config option
- Replace previous DUK_USE_ALIGN_4 and DUK_USE_ALIGN_8 with a cleaner
DUK_USE_ALIGN_BY config option (allowed values 1, 4, 8)
- Add fastpath tag in anticipation of automatic fastpath suggestions
or warnings
Add support for handling Proxy instanceof correctly, without support for
'getPrototypeOf' trap. The instanceof check traverses through the Proxy
target.
Also remove mostly unused old debug code.
Debug code doesn't have access to 'heap' so it cannot decode pointers.
Cause an #error for now if both debug prints and pointer compression
are enabled at the same time.
Remove duk_debug_hobject.c from make and dist. It was out of date and
not used in practice anymore.
Add a C API binding for Object.defineProperty(): duk_def_prop().
In addition to Object.defineProperty() features, the API call provides a
"force" flag which allows properties to be added to non-extensible objects
and non-configurable properties to be changed (except virtual properties
which are immutable).
Because the name duk_def_prop() conflicts with internal calls, rename them
from duk_def_prop*() to duk_xdef_prop*(). This rename also makes it clearer
that the internal duk_xdef_prop*() calls have non-compliant, internal
semantics.
Also reimplement Object.defineProperty() and Object.defineProperties() (and
duk_def_prop()) so that they share the same internal helpers, and there is
no need for a temporary property descriptor object which is unnecessary churn.
Detailed changes:
- New helper to prepare (validate and normalize) property descriptors
- New helper to implement Object.defineProperty() internals, leaving
out validation of the property descriptor
- Reimplement Object.defineProperty() using the new helpers
- Reimplement Object.defineProperties() using the new helpers
- Reimplement duk_define_property() using the new helpers, so that a
temporary property descriptor object is no longer created
- Add support for "force" flag to Object.defineProperty()
Memory optimization work for very low memory devices (96 to 256kB system RAM).
Overall changes are:
- 16-bit fields for various internal structures to reduce their size
- Heap pointer compression to reduce pointer size to 16 bits
When DUK_OPT_LIGHTFUNC_BUILTINS and the new low memory options are enabled,
Duktape initial heap memory usage is about 23kB (compared to baseline of
about 45kB) on x86.
Unless low memory feature options are enabled, there should be no visible
changes to Duktape behavior.
More detailed changes:
- 16-bit changes for duk_heaphdr: pointer compression, refcount
- 16-bit changes for duk_hstring: hash, blen, and clen can all be 16 bits,
use 0xFFFF as string byte length limit (call sites ensure this limit is
never exceeded)
- 16-bit changes for duk_hbuffer, use 0xFFFF as buffer length limit
- 16-bit fields for hobject size (entry part, array part), drop hash part
since it's not usually needed for extremely low memory environments
- 16-bit changes for duk_hcompiledfunction
- Heap pointer packing for stringtable
- Heap pointer packing for 'strs' built-in strings list (saves around 600
to 700 bytes but may not be a good tradeoff because call site size will
increase)
Other changes:
- Heaphdr NULL init fix. The original macros were broken: the double/single
linked macro variants were the wrong way around. Now sets through macro
to work properly with compressed pointers.
- Rename duk_hbuffer CURR_DATA_PTR -> DATA_PTR to reduce macro length
(previous name was tediously long)
- Rename buffer "usable_size" to "alloc_size" throughout as they have been
the same for a while now (they used to differ when buffer had an extra NUL).
- Add memory optimization markers to Duktape.env (pointer compression and
individual 16-bit field options)
- Rename a few internal fields for clarity: duk_hobject 'p' to 'props',
heap->st to heap->strtable
- Add a safety check for buffer alloc size (should not be triggered but
prevents wrapping if call sites don't properly check for sizes)
- Other minor cleanups
When doing a single file build, drop DUK_INTERNAL_DECL declarations which
would otherwise be mapped to "static". This avoids the problem with C++
where a static data symbol is both forward declared and defined.
With this change static definitions must appear before their first use in
the single file build. This requires a change in combine_src.py which is
done in a separate commit.
Add an ignore_loop argument to duk_hobject_prototype_chain_contains() to
support this behavior. It depends on the context whether a prototype loop
should cause an error to be thrown or not.
e_used is actually used to track the number of entry part entries currently
GC reachable. Some of the entries may be NULL, indicating deleted keys.
The e_used value is also used as the index where the next insertion of a new
property key happens, so e_next is probably a more appropriate name and
doesn't incorrectly imply that the e_used count indicates actually used,
non-NULL key entries.
Lots of minor string format cleanups (casts mainly).
Add a special check to detect NULL pointers with %s/%p formats in debug
logging to avoid calling the platform sprintf() with a NULL value. This
is especially important for %s + NULL, which is not portable and may crash
on some platforms. Debug logging will now format these specially as "NULL"
and avoid calling the platform for formatting, so debug log call sites don't
need to be careful with NULL pointers any more.
Sami Vaarala
Bruce Pascoe