String output must either (a) eval() back as an equivalent object, OR
(b) eval() to a SyntaxError.
Previous Duktape output, conformant to ES5/ES5.1, matched FunctionDeclaration
syntax but didn't parse back as an equivalent function.
These can be used whenever we're 100% certain that the value stack index
exists and the type matches expected type. When these are true, a
duk_hstring, duk_hbuffer, or duk_hobject pointer fetch can be inlined to
small code.
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.
Saves a few hundred bytes of footprint:
* duk_dup_0() = duk_dup(ctx, 0), duk_dup_1() = duk_dup(ctx, 1), etc.
* duk_dup_m2() = duk_dup(ctx, -2), etc.
* duk_dup_m1() is not added, because duk_dup_top() is the same thing
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.
Eval code doesn't need an automatic prototype object, so avoid creating one.
This also avoids making the internal function which eval compiles to part of
a reference loop so that eval functions collect immediately.
Emscripten depends on a Function's .toString() having a certain format
(beyond what is guaranteed by the E5 specification). In particular, it
won't parse Duktape's current format where the function body is replaced
with a comment indicating the function type, e.g.:
function foo() {/* ecmascript */}
Change this format to indicate the function type using a string literal
(similarly to how directive prologue works):
function foo() {"ecmascript"}
This is equally informational and will work directly with Emscripten.
Also change handling for anonymous functions: substituting "anon" for an
anonymous function in an Ecmascript function's .toString() output is a bit
misleading. It also causes an Emscripten issue when a source regexp expects
there to be no name for an anonymous function in the .toString() output.
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()
* Fix outstanding FIXME issues for lightfunc semantics.
* Improve API and Ecmascript testcases to match.
* Clarify lightfunc limitations, e.g. finalizer limitations.
* Guide and API documentation changes for lightfuncs.
* Fix compile warning: duk_str_not_object unused.
A lot of changes to add preliminary lightfunc support:
* Add LIGHTFUNC tagged type to duk_tval.h and API.
* Internal changes for preliminary to support lightfuncs in call handling
and other operations (FIXMEs left in obvious places where support is
still missing after this commit)
* Preliminary Ecmascript and API testcases for lightfuncs
Detailed notes:
* Because magic is signed, reading it back involves sign extension which is
quite verbose to do in C. Use macros for reading the magic value and other
bit fields encoded in the flags.
* Function.prototype.bind(): the 'length' property of a bound function now
comes out wrong. We could simply look up the virtual 'length' property
even if h_target is NULL: no extra code and binding is relatively rare in
hot paths. Rewrite more cleanly in any case.
* The use flag DUK_USE_LIGHTFUNC_BUILTINS controls the forced lightfunc
conversion of built-ins. This results in non-compliant built-ins but
significant memory savings in very memory poor environments.
* Reject eval(), Thread.yield/resume as lightfuncs. These functions have
current assertions that they must be called as fully fledged functions.
* Lightfuncs are serialized like ordinary functions for JSON, JX, and JC
by this diff.
* Add 'magic' to activation for lightfuncs. It will be needed for lightweight
functions: we don't have the duk_tval related to the lightfunc, so we must
copy the magic value to the activation when a call is made.
* When lightfuncs are used as property lookup base values, continue property
lookup from the Function.prototype object. This is necessary to allow e.g.
``func.call()`` and ``func.apply()`` to be used.
* Call handling had to be reworked for lightfuncs, especially how bound
function chains are handled. This is a relatively large change but is
necessary to support lightweight functions properly in bound function
resolution.
The current solution is not ideal. The bytecode executor will first try an
ecma-to-ecma call setup which resolves the bound function chain first. If
the final, unbound function is not viable (a native function) the call setup
returns with an error code. The caller will then perform a normal call.
Although bound function resolution has already been done, the normal call
handling code will re-do it (and detect there is nothing to do).
This situation could be avoided by decoupling bound function handling and
effective this binding computation from the actual call setup. The caller
could then to do this prestep first, and only then decide whether to use an
ecma-to-ecma call or an ordinary heavyweight call.
Remove duk__find_nonbound_function as unused.
* Use indirect magic to allow LIGHTFUNCs for Date. Most of the built-in
functions not directly eligible as lightfuncs are the Date built-in methods,
whose magic values contain too much information to fit into the 8-bit magic
of a LIGHTFUNC value.
To work around this, add an array (duk__date_magics[]) containing the
actual control flags needed by the built-ins, and make the Date built-in
magic value an index into this table. With this change Date built-ins are
successfully converted to lightfuncs.
Testcase fixes:
- Whitespace fixes
- Print error for indirect eval error to make diagnosis easier
- Fix error string to match errmsg updated in this branch
When a base object has the special [[Get]] behavior described in E5.1
Section 15.3.5.4 or 10.6 for the "caller" property, there is a question
whether a TypeError is thrown when the "caller" property value is a
bound strict function (or only when the value is a non-bound strict
function).
This commit changes the behavior so that a TypeError is also thrown
when the "caller" value is a bound function, by ensuring that strict
bound functions have the "strict" internal flag set.
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