Assert that code is only ever called from a GC callback, disable the static
rooting hazard analysis and assert if any allocation that could potentially
trigger a GC occurs while this guard object is live.
Diagnostic assert (see MOZ_DIAGNOSTIC_ASSERT) that GC cannot occur while this
class is live. This class does not disable the static rooting hazard
analysis.
Pass a subclass of this “abstract” class to callees to require that they
never GC. Subclasses can use assertions or the hazard analysis to ensure no
GC happens.
Save and later restore the current exception state of a given JSContext.
This is useful for implementing behavior in C++ that’s like try/catch
or try/finally in JS.
Supply an alternative stack to incorporate into captured SavedFrame
backtraces as the imputed caller of asynchronous JavaScript calls, like async
function resumptions and DOM callbacks.
Compilation options stored on the stack. An instance of this type
simply holds references to dynamically allocated resources (element;
filename; source map URL) that are owned by something else. If you
create an instance of this type, it’s up to you to guarantee that
everything you store in it will outlive it.
Capture the first frame with the given principals. By default, do not
consider self-hosted frames with the given principals as satisfying the stack
capture.
Reference to a T that has been rooted elsewhere. This is most useful
as a parameter type, which guarantees that the T lvalue is properly
rooted. See “Move GC Stack Rooting” above.
This hash policy avoids flattening ropes (which perturbs the site being
measured and requires a JSContext) at the expense of doing a FULL ROPE COPY
on every hash and match! Beware.
The C-style API calls to read and write structured clones are fragile –
they rely on the caller to properly handle ownership of the clone data, and
the handling of the input data as well as the interpretation of the contents
of the clone buffer are dependent on the callbacks passed in. If you
serialize and deserialize with different callbacks, the results are
questionable.
Wrapper to relace JSNative for JSPropertySpecs and JSFunctionSpecs. This will
allow us to pass one JSJitInfo per function with the property/function spec,
without additional field overhead.
Description of a property. JS_DefineProperties and JS_InitClass take arrays
of these and define many properties at once. JS_PSG, JS_PSGS and JS_PS_END
are helper macros for defining such arrays.
JSStructuredCloneData represents structured clone data together with the
information needed to read/write/transfer/free the records within it, in the
form of a set of callbacks.
A saved job queue, represented however the JobQueue implementation pleases.
Use AutoDebuggerJobQueueInterruption rather than trying to construct one of
these directly; see documentation there.
Holds data about a notable class (one whose combined object and shape
instances use more than a certain amount of memory) so we can report it
individually.
Holds data about a notable script source file (one whose combined
script sources use more than a certain amount of memory) so we can report it
individually.
The ConsumeStreamCallback is called from an active JSContext, passing a
StreamConsumer that wishes to consume the given host object as a stream of
bytes with the given MIME type. On failure, the embedding must report the
appropriate error on ‘cx’. On success, the embedding must call
consumer->consumeChunk() repeatedly on any thread until exactly one of:
Compilation options, with dynamic lifetime. An instance of this type
makes a copy of / holds / roots all dynamically allocated resources
(principals; elements; strings) that it refers to. Its destructor frees
/ drops / unroots them. This is heavier than CompileOptions, below, but
unlike CompileOptions, it can outlive any given stack frame.
A structure that represents a property on an object, or the absence of a
property. Use {,Mutable}Handle to interact with
instances of this structure rather than interacting directly with member
fields.
RealmCreationOptions specifies options relevant to creating a new realm, that
are either immutable characteristics of that realm or that are discarded
after the realm has been created.
RealmOptions specifies realm characteristics: both those that can’t be
changed on a realm once it’s been created (RealmCreationOptions), and those
that can be changed on an existing realm (RealmBehaviors).
Regular expression flag values, suitable for initializing a collection of
regular expression flags as defined below in |RegExpFlags|. Flags are listed
in alphabetical order by syntax – /d, /g, /i, /m, /s, /u, /v, /y.
SafelyInitialized::create() creates a safely-initialized |T|, suitable for
use as a default value in situations requiring a safe but arbitrary |T|
value. Implemented as a static method of a struct to allow partial
specialization for subclasses via the Enable template parameter.
PrepareScriptEnvironmentAndInvoke asserts the embedder has registered a
ScriptEnvironmentPreparer and then it calls the preparer’s ‘invoke’ method
with the given |closure|, with the assumption that the preparer will set up
any state necessary to run script in |global|, invoke |closure| with a valid
JSContext*, report any exceptions thrown from the closure, and return.
This class holds information about the memory taken up by identical copies of
a particular string. Multiple JSStrings may have their sizes aggregated
together into one StringInfo object. Note that two strings with identical
chars will not be aggregated together if one is a short string and the other
is not.
The TenuredHeap class is similar to the Heap class above in that it
encapsulates the GC concerns of an on-heap reference to a JS object. However,
it has two important differences:
The WasmModule interface allows the embedding to hold a reference to the
underlying C++ implementation of a JS WebAssembly.Module object for purposes
of efficient postMessage() and (de)serialization from a random thread.
already_AddRefed cooperates with reference counting smart pointers to enable
you to assign in a pointer without |AddRef|ing it. You might want to use
this as a return type from a function that returns an already |AddRef|ed
pointer. Or, you might want to use this as a parameter type in a function
that wants to force a transfer-of-ownership from a RefPtr in the caller (for
example, if the function expects callers to pass in a newly-created object,
which the function then takes ownership of).
An enum that describes what this getter/setter/method aliases. This
determines what things can be hoisted past this call, and if this
call is movable what it can be hoisted past.
During global creation, we fire notifications to callbacks registered
via the Debugger API. These callbacks are arbitrary script, and can touch
the global in arbitrary ways. When that happens, the global should not be
in a half-baked state. But this creates a problem for consumers that need
to set slots on the global to put it in a consistent state.
If IsIncrementalGCInProgress(cx), this call aborts the ongoing collection and
performs whatever work needs to be done to return the collector to its idle
state. This may take an arbitrarily long time. When this function returns,
IsIncrementalGCInProgress(cx) will always be false.
Advise the GC of external memory owned by a JSObject. This is used to
determine when to collect zones. Calls must be matched by calls to
RemoveAssociatedMemory() when the memory is deallocated or no longer owned by
the object.
Convert the given BigInt to a Number value as if calling the Number
constructor on it
(https://tc39.es/ecma262/#sec-number-constructor-number-value). The value
may be rounded if it doesn’t fit without loss of precision.
Given a SavedFrame JSObject stack, stringify it in the same format as
Error.prototype.stack. The stringified stack out parameter is placed in the
cx’s compartment. Defaults to the empty string.
Create a Promise with the given fulfill/reject handlers, that will be
fulfilled/rejected with the value/reason that the promise promise is
fulfilled/rejected with.
Capture the current call stack as a chain of SavedFrame JSObjects, and set
|stackp| to the SavedFrame for the youngest stack frame, or nullptr if there
are no JS frames on the stack.
Check whether the given source is a valid regexp. If the regexp parses
successfully, returns true and sets |error| to undefined. If the regexp
has a syntax error, returns true, sets |error| to that error object, and
clears the exception. Returns false on OOM or over-recursion.
Compile a function with envChain plus the global as its scope chain.
envChain must contain objects in the current compartment of cx. The actual
scope chain used for the function will consist of With wrappers for those
objects, followed by the current global of the compartment cx is in. This
global must not be explicitly included in the scope chain.
Compile a function with envChain plus the global as its scope chain.
envChain must contain objects in the current compartment of cx. The actual
scope chain used for the function will consist of With wrappers for those
objects, followed by the current global of the compartment cx is in. This
global must not be explicitly included in the scope chain.
Parse the given source buffer as a JSON module in the scope of the current
global of cx and return a synthetic module record. An error is reported if a
UTF-8 encoding error is encountered.
Parse the given source buffer as a module in the scope of the current global
of cx and return a source text module record. An error is reported if a
UTF-8 encoding error is encountered.
Compile the UTF-8 contents of the given file into a script. It is an error
if the file contains invalid UTF-8. Return the script on success, or return
null on failure (usually with an error reported).
Compile the UTF-8 contents of the file at the given path into a script.
(The path itself is in the system encoding, not [necessarily] UTF-8.) It
is an error if the file’s contents are invalid UTF-8. Return the script on
success, or return null on failure (usually with an error reported).
Returns true if there are any live SharedArrayBuffer objects, including those
for wasm memories, associated with the context. This is conservative,
because it does not run GC. Some dead objects may not have been collected
yet and thus will be thought live.
Given a SavedFrame object, convert it and its transitive parents to plain
objects. Because SavedFrame objects store their properties on the prototype,
they cannot be usefully stringified to JSON. Assigning their properties to
plain objects allow those objects to be stringified and the saved frame stack
can be encoded as a string.
Create a synthetic module record that exports a single value as its default
export. The caller is responsible for providing the already-constructed
value to export.
Attempt to disable Wasm’s usage of reserving a large virtual memory
allocation to avoid bounds checking overhead. This must be called before any
Wasm module or memory is created in this process, or else this function will
fail.
As above, but providing an explicit scope chain. envChain must not include
the global object on it; that’s implicit. It needs to contain the other
objects that should end up on the script’s scope chain.
Evaluate the provided UTF-8 data in the scope of the current global of |cx|,
and return the completion value in |rval|. If the data contains invalid
UTF-8, an error is reported.
Evaluate the UTF-8 contents of the file at the given path, and return the
completion value in |rval|. (The path itself is UTF-8 encoded, too.) If
the contents contain any malformed UTF-8, an error is reported.
If the given object is an exception object (or an unwrappable
cross-compartment wrapper for one), return the stack for that exception, if
any. Will return null if the given object is not an exception object
(including if it’s null or a security wrapper that can’t be unwrapped) or if
the exception has no stack.
Execute a regexp on a given input, starting from |indexp|.
This is the same as ExecuteRegExp, except it does not update the RegExp
statics and can be called without a global object.
If IsIncrementalGCInProgress(cx), this call finishes the ongoing collection
by performing an arbitrarily long slice. If !IsIncrementalGCInProgress(cx),
this is equivalent to NonIncrementalGC. When this function returns,
IsIncrementalGCInProgress(cx) will always be false.
Return a pointer to the start of the data referenced by a typed array. The
data is still owned by the typed array, and should not be modified on
another thread. Furthermore, the pointer can become invalid on GC (if the
data is small and fits inside the array’s GC header), so callers must take
care not to hold on across anything that could GC.
Determine the ECMAScript “class” – Date, String, RegExp, and all the other
builtin object types (described in ECMAScript in terms of an objecting having
“an [[ArrayBufferData]] internal slot” or similar language for other kinds of
object – of the provided object.
If args.get(0) is one of the strings “string”, “number”, or “default”, set
result to JSTYPE_STRING, JSTYPE_NUMBER, or JSTYPE_UNDEFINED accordingly and
return true. Otherwise, return false with a TypeError pending.
Get the first SavedFrame object in this SavedFrame stack whose principals are
subsumed by the given |principals|. If there is no such frame, return
nullptr.
Get or set function’s reserved slot value.
fun should be a function created with *WithReserved API above.
Such functions have 2 reserved slots, and which can be either 0 or 1.
Get the global object associated with an object’s realm. The object must not
be a cross-compartment wrapper (because CCWs are shared by all realms in the
compartment).
Returns the given Promise’s activation behavior state flag per above as a
JS::PromiseUserInputEventHandlingState value. All promises are created with
the DontCare state by default.
Given a SavedFrame JSObject, get its asyncParent SavedFrame object or nullptr
if there is no asyncParent. The asyncParentp out parameter is NOT
guaranteed to be in the cx’s compartment. Defaults to nullptr.
Given a SavedFrame JSObject, get its functionDisplayName string, or nullptr
if SpiderMonkey was unable to infer a name for the captured frame’s
function. Defaults to nullptr.
Given a SavedFrame JSObject, get its parent SavedFrame object or nullptr if
it is the oldest frame in the stack. The parentp out parameter is NOT
guaranteed to be in the cx’s compartment. Defaults to nullptr.
Informs the JS engine that the scripted caller should be hidden. This can be
used by the embedding to maintain an override of the scripted caller in its
calculations, by hiding the scripted caller in the JS engine and pushing data
onto a separate stack, which it inspects when DescribeScriptedCaller returns
null.
Return whether an incremental GC has work to do on the foreground thread and
would make progress if a slice was run now. If this returns false then the GC
is waiting for background threads to finish their work and a slice started
now would return immediately.
Perform a slice of an ongoing incremental collection. When this function
returns, the collection may not be complete. It must be called repeatedly
until !IsIncrementalGCInProgress(cx).
Initialize the async task callbacks. Embedders must use this or else call
js::UseInternalJobQueues to select a default implementation built into
SpiderMonkey. This latter depends on the embedding to call js::RunJobs on
the JavaScript thread to process queued Dispatchables at appropriate times.
Identical to IsArray above, but the nature of the object (if successfully
determined) is communicated via |*answer|. In particular this method
returns true and sets |*answer = IsArrayAnswer::RevokedProxy| when called on
a revoked proxy.
Check whether obj supports the JS::GetArrayBufferMaybeShared* APIs. Note
that this may return false if a security wrapper is encountered that denies
the unwrapping. If this test succeeds, then it is safe to call the various
predicate and accessor JSAPI calls defined below.
Determine whether |value| is an Array object or a wrapper around one. (An
ES6 proxy whose target is an Array object, e.g.
|var target = [], handler = {}; Proxy.revocable(target, handler).proxy|, is
not considered to be an Array.)
Determine whether |obj| is an Array object or a wrapper around one. (An
ES6 proxy whose target is an Array object, e.g.
|var target = [], handler = {}; Proxy.revocable(target, handler).proxy|, is
not considered to be an Array.)
Return true if the given object is a constructor. In ES6 terms, an object is
a constructor if it has a [Construct] internal method. The expression
new obj() throws a TypeError if obj is not a constructor.
Check whether the obj is a detached ArrayBufferObject. Note that this may
return false if a security wrapper is encountered that denies the
unwrapping.
Whether we are poisoning unused/released data for error detection. Governed
by the JS_GC_ALLOW_EXTRA_POISONING #ifdef as well as the
javascript.options.extra_gc_poisoning pref.
Returns true if incremental GC is enabled. Simply having incremental GC
enabled is not sufficient to ensure incremental collections are happening.
See the comment “Incremental GC” above for reasons why incremental GC may be
suppressed. Inspection of the “nonincremental reason” field of the
GCDescription returned by GCSliceCallback may help narrow down the cause if
collections are not happening incrementally when expected.
Check whether the obj is ArrayBufferObject and memory mapped. Note that this
may return false if a security wrapper is encountered that denies the
unwrapping.
Returns true if |obj| is a plain object: a standard JS object with no exotic
behavior, such as one created from a ‘{}’ object literal or ‘Object.create’.
Unlike |GetBuiltinClass|, this does not unwrap proxies and tests |obj|
directly.
Check whether obj supports the JS::GetSharedArrayBuffer* APIs. Note that
this may return false if a security wrapper is encountered that denies the
unwrapping. If this test succeeds, then it is safe to call the various
accessor JSAPI calls defined below.
This function calls |realmCallback| on every realm. Beware that there is no
guarantee that the realm will survive after the callback returns. Also,
barriers are disabled via the TraceSession.
A JS context always has an “owner thread”. The owner thread is set when the
context is created (to the current thread) and practically all entry points
into the JS engine check that a context (or anything contained in the
context: runtime, compartment, object, etc) is only touched by its owner
thread. Embeddings may check this invariant outside the JS engine by calling
JS_AbortIfWrongThread (which will abort if not on the owner thread, even for
non-debug builds).
For JS_DecodeBytes, set *dstlenp to the size of the destination buffer before
the call; on return, *dstlenp contains the number of characters actually
stored. To determine the necessary destination buffer size, make a sizing
call that passes nullptr for dst.
Freeze obj, and all objects it refers to, recursively. This will not recurse
through non-extensible objects, on the assumption that those are already
deep-frozen.
Encode string into a buffer. The function does not stores an additional
zero byte. The function returns (size_t) -1 if the string can not be
encoded into bytes with no error reported. Otherwise it returns the number
of bytes that are necessary to encode the string. If that exceeds the
length parameter, the string will be cut and only length bytes will be
written into the buffer.
If the given object is an exception object, the exception will have (or be
able to lazily create) an error report struct, and this function will
populate |errorReport| with it and return true. Otherwise, returns false.
As above, but providing an explicit scope chain. envChain must not include
the global object on it; that’s implicit. It needs to contain the other
objects that should end up on the script’s scope chain.
Return the ArrayBuffer or SharedArrayBuffer underlying an ArrayBufferView.
This may return a detached buffer. |obj| must be an object that would
return true for JS_IsArrayBufferViewObject().
Return a “fixed” pointer (one that will not move during a GC) to the
ArrayBufferView’s data. Note that this will not keep the object alive; the
holding object should be rooted or traced. If the view is storing the data
inline, this will copy the data to the provided buffer, returning nullptr if
bufSize is inadequate.
Return the ‘callbacks’ arg passed to JS_NewExternalStringLatin1,
JS_NewExternalUCString, JS_NewMaybeExternalStringLatin1,
or JS_NewMaybeExternalUCString.
If |obj| (underneath any functionally-transparent wrapper proxies) has as
its [[GetPrototypeOf]] trap the ordinary [[GetPrototypeOf]] behavior defined
for ordinary objects, set |*isOrdinary = true| and store |obj|’s prototype
in |result|. Otherwise set |*isOrdinary = false|. In case of error, both
outparams have unspecified value.
Get number of bytes in the string encoding (without accounting for a
terminating zero bytes. The function returns (size_t) -1 if the string
can not be encoded into bytes and reports an error using cx accordingly.
Spidermonkey does not have a good way of keeping track of what compartments
should be marked on their own. We can mark the roots unconditionally, but
marking GC things only relevant in live compartments is hard. To mitigate
this, we create a static trace hook, installed on each global object, from
which we can be sure the compartment is relevant, and mark it.
Copy the own properties of src to dst in a fast way. src and dst must both
be native and must be in the compartment of cx. They must have the same
class, the same parent, and the same prototype. Class reserved slots will
NOT be copied.
Check whether obj supports JS_GetArrayBufferView* APIs. Note that this may
return false if a security wrapper is encountered that denies the
unwrapping. If this test or one of the more specific tests succeeds, then it
is safe to call the various ArrayBufferView accessor JSAPI calls defined
below.
Determine whether obj is extensible. Extensible objects can have new
properties defined on them. Inextensible objects can’t, and their
[[Prototype]] slot is fixed as well.
Test whether the given chars + length are a valid ECMAScript identifier.
This version is infallible, so just returns whether the chars are an
identifier.
Check whether obj supports JS_GetTypedArray* APIs. Note that this may return
false if a security wrapper is encountered that denies the unwrapping. If
this test or one of the JS_Is*Array tests succeeds, then it is safe to call
the various accessor JSAPI calls defined below.
This function calls |compartmentCallback| on every compartment until either
all compartments have been iterated or CompartmentIterResult::Stop is
returned. Beware that there is no guarantee that the compartment will survive
after the callback returns. Also, barriers are disabled via the TraceSession.
This function calls |compartmentCallback| on every compartment in the given
zone until either all compartments have been iterated or
CompartmentIterResult::Stop is returned. Beware that there is no guarantee
that the compartment will survive after the callback returns. Also, barriers
are disabled via the TraceSession.
Mark a jsid after entering a new compartment. Different zones separately
mark the ids in a runtime, and this must be used any time an id is obtained
from one compartment and then used in another compartment, unless the two
compartments are guaranteed to be in the same zone.
If the bufSize passed to JS_GetArrayBufferViewFixedData is at least this
many bytes, then any copied data is guaranteed to fit into the provided
buffer.
Create a new DataView using the given buffer for storage. The given buffer
must be an ArrayBuffer or SharedArrayBuffer (or a cross-compartment wrapper
of either type), and the offset and length must fit within the bounds of the
buffer. Currently, nullptr will be returned and an exception will be thrown
if these conditions do not hold, but do not depend on that behavior.
Create a dependent string, i.e., a string that owns no character storage,
but that refers to a slice of another string’s chars. Dependent strings
are mutable by definition, so the thread safety comments above apply.
Fill “properties” with a list of standard class names that have not yet been
resolved on “obj”. This can be used as (part of) a newEnumerate class hook
on a global. Already-resolved things are excluded because they might have
been deleted by script after being resolved and enumeration considers
already-defined properties anyway.
Fill “properties” with a list of standard class names. This can be used for
proxies that want to define behavior that looks like enumerating a global
without touching the global itself.
Create a new JSString whose chars member may refer to external memory.
If a new external string is allocated, |*allocatedExternal| is set to true.
Otherwise the returned string is either not an external string or an
external string allocated by a previous call and |*allocatedExternal| is set
to false. If |*allocatedExternal| is false, |fin| won’t be called.
A constructor can request that the JS engine create a default new ‘this’
object of the given class, using the callee to determine parentage and
[[Prototype]].
Allocate an object in exactly the same way as JS_NewObjectWithGivenProto, but
without invoking the metadata callback on it. This allows creation of
internal bookkeeping objects that are guaranteed to not have metadata
attached to them.
Infallible predicate to test whether obj is a function object (faster than
comparing obj’s class name to “Function”, but equivalent unless someone has
overwritten the “Function” identifier with a different constructor and then
created instances using that constructor that might be passed in as obj).
Performs the JSON.parse operation as specified by ECMAScript, using the
given |reviver| argument as the corresponding optional argument to that
function.
Performs the JSON.parse operation as specified by ECMAScript, using the
given |reviver| argument as the corresponding optional argument to that
function.
Resolve id, which must contain either a string or an int, to a standard
class name in obj if possible, defining the class’s constructor and/or
prototype and storing true in *resolved. If id does not name a standard
class or a top-level property induced by initializing a standard class,
store false in *resolved and just return true. Return false on error,
as usual for bool result-typed API entry points.
This function can be used to track memory used by ICU. If it is called, it
must be called before JS_Init. Don’t use it unless you know what you’re
doing!
Attempt to make the [[Prototype]] of |obj| immutable, such that any attempt
to modify it will fail. If an error occurs during the attempt, return false
(with a pending exception set, depending upon the nature of the error). If
no error occurs, return true with |*succeeded| set to indicate whether the
attempt successfully made the [[Prototype]] immutable.
Performs the JSON.stringify operation, as specified by ECMAScript, except
writing stringified data by exactly one call of |callback|, passing |data| as
argument.
Given a buffer, return false if the buffer might become a valid JavaScript
script with the addition of more lines, or true if the validity of such a
script is conclusively known (because it’s the prefix of a valid script –
and possibly the entirety of such a script).
Same as JS_WriteUint32Pair but let implicit conversions from integers of a
wider range happen without performing bounds checks.
Using this function directly is not recommended: it is here mainly to allow
compiler optimizations in JS_WriteUint32Pair for cases where integer values
are known at compile time (in which case .isValid() calls can be elided)
Same as above, but for buffers that will be used with the BYOB
(Bring Your Own Buffer) JSString creation functions, such as
JS_NewLatin1String and JS_NewUCString
Inform the runtime that the job queue is empty and the embedding is going to
execute its last promise job. The runtime may now choose to skip creating
promise jobs for asynchronous execution and instead continue execution
synchronously. More specifically, this optimization is used to skip the
standard job queuing behavior for await operations in async functions.
Inform the runtime that job queue is no longer empty. The runtime can now no
longer skip creating promise jobs for asynchronous execution, because
pending jobs in the job queue must be executed first to preserve the FIFO
(first in - first out) property of the queue. This effectively undoes
JobQueueIsEmpty and re-enables the standard job queuing behavior.
In memory reporting, we have concept of “sundries”, line items which are too
small to be worth reporting individually. Under some circumstances, a memory
reporter gets tossed into the sundries bucket if it’s smaller than
MemoryReportingSundriesThreshold() bytes.
Create an Array from the current realm with the given length and allocate
memory for all its elements. (The elements nonetheless will not exist as
properties on the returned array until values have been assigned to them.)
Create a new function based on the given JSFunctionSpec, *fs.
id is the result of a successful call to
PropertySpecNameToId(cx, fs->name, &id) or
PropertySpecNameToPermanentId(cx, fs->name, &id).
Create a new mapped ArrayBuffer with the given memory mapped contents. It
must be legal to free the contents pointer by unmapping it. On success,
ownership is transferred to the new mapped ArrayBuffer.
Create a new SharedArrayBuffer with the given byte length. This
may only be called if
JS::RealmCreationOptionsRef(cx).getSharedMemoryAndAtomicsEnabled() is
true.
Like NewStringFromLatin1Buffer, but can be used to avoid refcounting overhead
in cases where the returned string doesn’t use the buffer. The caller must
ensure the buffer outlives this call.
Like NewStringFromUTF8Buffer, but can be used to avoid refcounting overhead
in cases where the returned string doesn’t use the buffer. The caller must
ensure the buffer outlives this call.
Create a BigInt from a floating-point value. If the number isn’t integral
(that is, if it’s NaN, an infinity, or contains a fractional component),
this function returns null and throws an exception.
On success, returns true, setting |*isRegExp| to true if |obj| is a RegExp
object or a wrapper around one, or to false if not. Returns false on
failure.
When performing an incremental GC, the zones that were selected for the
previous incremental slice must be selected in subsequent slices as well.
This function selects those slices automatically.
Release the allocated resource of mapped ArrayBuffer contents before the
object is created.
If a new object has been created by JS::NewMappedArrayBufferWithContents()
with this content, then JS::DetachArrayBuffer() should be used instead to
release the resource used by the object.
Advise the GC that external memory reported by JS::AddAssociatedMemory() is
no longer owned by a JSObject. Calls must match those to
AddAssociatedMemory().
An uncatchable exception is used to terminate execution by returning false
or nullptr without reporting a pending exception on the context. These
exceptions are called “uncatchable” because try-catch can’t be used to catch
them.
Set module status to New and clear the [[LoadedModules]] slot and in a Cycloc
Module.
Used to reset modules that were preloaded earlier, in case the resolution of
their specifiers may have changed.
Re-query the system to determine the current time zone adjustment from UTC,
including any component due to DST. If the time zone has changed, this will
cause all Date object non-UTC methods and formatting functions to produce
appropriately adjusted results.
Stores |SameValue(v1, v2)| to |*equal| – using the SameValue operation
defined in ECMAScript, initially exposed to script as |Object.is|. SameValue
behaves identically to strict equality, except that it equates two NaN values
and does not equate differently-signed zeroes. It performs no conversions on
|v1| or |v2| before comparing.
Called when generating a GC slice budget. It allows the embedding to control
the duration of slices and potentially check an interrupt flag as well. For
internally triggered GCs, the given millis parameter is the JS engine’s
internal scheduling decision, which the embedding can choose to ignore.
(Otherwise, it will be the value that was passed to eg
JS::IncrementalGCSlice()).
The GC slice callback is called at the beginning and end of each slice. This
callback may be used for GC notifications as well as to perform additional
marking.
Tell JS engine whether Profile Timeline Recording is enabled or not.
If Profile Timeline Recording is enabled, data shown there like stack won’t
be optimized out.
This is global state and not associated with specific runtime or context.
Sets the callback that’s invoked whenever a Promise is rejected without
a rejection handler, and when a Promise that was previously rejected
without a handler gets a handler attached.
Begin an incremental collection and perform one slice worth of work. When
this function returns, the collection may not be complete.
IncrementalGCSlice() must be called repeatedly until
!IsIncrementalGCInProgress(cx).
Steal the contents of the given ArrayBuffer. The ArrayBuffer has its length
set to 0 and its contents array cleared. The caller takes ownership of the
return value and must free it or transfer ownership via
JS::NewArrayBufferWithContents when done using it.
Create a BigInt by parsing a string using the ECMAScript StringToBigInt
algorithm (https://tc39.es/ecma262/#sec-stringtobigint). Latin1 and two-byte
character ranges are supported. It may be convenient to use
JS::ConstLatin1Chars or JS::ConstTwoByteChars.
Performs the JSON.stringify operation, as specified by ECMAScript, except
writing stringified data by one call of |callback|, passing |data| as
argument.
An API akin to JS_Stringify but with the goal of not having observable
side-effects when the stringification is performed. This means it does not
allow a replacer or a custom space and has the following constraints on its
input:
Unsets the gray bit for anything reachable from |thing|. |kind| should not be
JS::TraceKind::Shape. |thing| should be non-null. The return value indicates
if anything was unmarked.
Callback to notify the embedder that a background task has finished. This can
be used to keep the JSContext’s thread alive if it’s subject to garbage
collection (e.g. as web workers are).
Callback to notify the embedder that a background task has begun. This can
be used to keep the JSContext’s thread alive if it’s subject to garbage
collection (e.g. as web workers are).
Return the buildId (represented as a sequence of characters) associated with
the currently-executing build. If the JS engine is embedded such that a
single cache entry can be observed by different compiled versions of the JS
engine, it is critical that the buildId shall change for each new build of
the JS engine.
Called when freeing a transferable handled by the embedding. Note that it
should never trigger a garbage collection (and will assert in a
debug build if it does.)
Reference to a T that has been rooted elsewhere. This is most useful
as a parameter type, which guarantees that the T lvalue is properly
rooted. See “Move GC Stack Rooting” above.
Reference to a T that has been rooted elsewhere. This is most useful
as a parameter type, which guarantees that the T lvalue is properly
rooted. See “Move GC Stack Rooting” above.
Reference to a T that has been rooted elsewhere. This is most useful
as a parameter type, which guarantees that the T lvalue is properly
rooted. See “Move GC Stack Rooting” above.
Reference to a T that has been rooted elsewhere. This is most useful
as a parameter type, which guarantees that the T lvalue is properly
rooted. See “Move GC Stack Rooting” above.
Reference to a T that has been rooted elsewhere. This is most useful
as a parameter type, which guarantees that the T lvalue is properly
rooted. See “Move GC Stack Rooting” above.
Finalize obj, which the garbage collector has determined to be unreachable
from other live objects or from GC roots. Obviously, finalizers must never
store a reference to obj.
The type of ObjectOps::funToString. This callback allows an object to
provide a custom string to use when Function.prototype.toString is invoked on
that object. A null return value means OOM.
A class with a resolve hook can optionally have a mayResolve hook. This hook
must have no side effects and must return true for a given id if the resolve
hook may resolve this id. This is useful when we’re doing a “pure” lookup: if
mayResolve returns false, we know we don’t have to call the effectful resolve
hook.
The type of ObjectOps::enumerate. This callback overrides a portion of
SpiderMonkey’s default [[Enumerate]] internal method. When an ordinary object
is enumerated, that object and each object on its prototype chain is tested
for an enumerate op, and those ops are called in order. The properties each
op adds to the ‘properties’ vector are added to the set of values the for-in
loop will iterate over. All of this is nonstandard.
Callback used by the wrap hook to ask the embedding to prepare an object
for wrapping in a context. This might include unwrapping other wrappers
or even finding a more suitable object for the new compartment. If |origObj|
is non-null, then it is the original object we are going to swap into during
a transplant.
Resolve a lazy property named by id in obj by defining it directly in obj.
Lazy properties are those reflected from some peer native property space
(e.g., the DOM attributes for a given node reflected as obj) on demand.
Function type for trace operation of the class called to enumerate all
traceable things reachable from obj’s private data structure. For each such
thing, a trace implementation must call JS::TraceEdge on the thing’s
location.
Callback used to ask the embedding for the cross compartment wrapper handler
that implements the desired prolicy for this kind of object in the
destination compartment. |obj| is the object to be wrapped. If |existing| is
non-nullptr, it will point to an existing wrapper object that should be
re-used if possible. |existing| is guaranteed to be a cross-compartment
wrapper with a lazily-defined prototype and the correct global. It is
guaranteed not to wrap a function.
If a large allocation fails when calling pod_{calloc,realloc}CanGC, the JS
engine may call the large-allocation-failure callback, if set, to allow the
embedding to flush caches, possibly perform shrinking GCs, etc. to make some
room. The allocation will then be retried (and may still fail.) This callback
can be called on any thread and must be set at most once in a process.
Unlike the error reporter, which is only called if the exception for an OOM
bubbles up and is not caught, the OutOfMemoryCallback is called immediately
at the OOM site to allow the embedding to capture the current state of heap
allocation before anything is freed. If the large-allocation-failure callback
is called at all (not all allocation sites call the large-allocation-failure
callback on failure), it is called before the out-of-memory callback; the
out-of-memory callback is only called if the allocation still fails after the
large-allocation-failure callback has returned.
This is called when JS_ReadStructuredClone receives a transferable object
not known to the engine. If this hook does not exist or returns false, the
JS engine calls the reportError op if set, otherwise it throws a
DATA_CLONE_ERR DOM Exception. This method is called before any other
callback and must return a non-null object in returnObject on success.
Result is intended to be the return type of JSAPI calls and internal
functions that can run JS code or allocate memory from the JS GC heap. Such
functions can:
Local variable of type T whose value is always rooted. This is typically
used for local variables, or for non-rooted values being passed to a
function that requires a handle, e.g. Foo(Root(cx, x)).
Local variable of type T whose value is always rooted. This is typically
used for local variables, or for non-rooted values being passed to a
function that requires a handle, e.g. Foo(Root(cx, x)).
Called when a SharedArrayBuffer (including one owned by a Wasm memory object)
has been processed in context cx by structured cloning. If receiving is
true then the SAB has been received from a channel and a new SAB object has
been created; if false then an existing SAB has been serialized onto a
channel.
This is called when serialization or deserialization encounters an error.
To follow HTML5, the application must throw a DATA_CLONE_ERR DOMException
with error set to one of the JS_SCERR_* values.
Called when JS_WriteStructuredClone receives a transferable object not
handled by the engine. If this hook does not exist or returns false, the JS
engine will call the reportError hook or fall back to throwing a
DATA_CLONE_ERR DOM Exception. This method is called before any other
callback.
Structured data serialization hook. The engine can write primitive values,
Objects, Arrays, Dates, RegExps, TypedArrays, ArrayBuffers, Sets, Maps,
and SharedTypedArrays. Any other type of object requires application support.
This callback must first use the JS_WriteUint32Pair API to write an object
header, passing a value greater than JS_SCTAG_USER to the tag parameter.
Then it can use the JS_Write* APIs to write any other relevant parts of
the value v to the writer w. closure is any value passed to the
JS_WriteStructuredClone function.