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Split StructuredCloneHolder into Reader and Writer structs (servo#34792)
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Signed-off-by: webbeef <[email protected]>
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@webbeef
webbeef authored Dec 30, 2024
1 parent 9156ee3 commit 1296c71
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Showing 5 changed files with 67 additions and 111 deletions.
6 changes: 3 additions & 3 deletions components/script/dom/bindings/serializable.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@
//! (<https://html.spec.whatwg.org/multipage/#serializable-objects>).
use crate::dom::bindings::reflector::DomObject;
use crate::dom::bindings::structuredclone::StructuredDataHolder;
use crate::dom::bindings::structuredclone::{StructuredDataReader, StructuredDataWriter};
use crate::dom::globalscope::GlobalScope;
use crate::script_runtime::CanGc;

Expand All @@ -22,11 +22,11 @@ pub struct StorageKey {
/// <https://html.spec.whatwg.org/multipage/#serializable>
pub trait Serializable: DomObject {
/// <https://html.spec.whatwg.org/multipage/#serialization-steps>
fn serialize(&self, sc_holder: &mut StructuredDataHolder) -> Result<StorageKey, ()>;
fn serialize(&self, sc_writer: &mut StructuredDataWriter) -> Result<StorageKey, ()>;
/// <https://html.spec.whatwg.org/multipage/#deserialization-steps>
fn deserialize(
owner: &GlobalScope,
sc_holder: &mut StructuredDataHolder,
sc_reader: &mut StructuredDataReader,
extra_data: StorageKey,
can_gc: CanGc,
) -> Result<(), ()>;
Expand Down
107 changes: 44 additions & 63 deletions components/script/dom/bindings/structuredclone.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@ pub(super) enum StructuredCloneTags {
unsafe fn read_blob(
owner: &GlobalScope,
r: *mut JSStructuredCloneReader,
sc_holder: &mut StructuredDataHolder,
sc_reader: &mut StructuredDataReader,
can_gc: CanGc,
) -> *mut JSObject {
let mut name_space: u32 = 0;
Expand All @@ -67,12 +67,8 @@ unsafe fn read_blob(
&mut index as *mut u32
));
let storage_key = StorageKey { index, name_space };
if <Blob as Serializable>::deserialize(owner, sc_holder, storage_key, can_gc).is_ok() {
let blobs = match sc_holder {
StructuredDataHolder::Read { blobs, .. } => blobs,
_ => panic!("Unexpected variant of StructuredDataHolder"),
};
if let Some(blobs) = blobs {
if <Blob as Serializable>::deserialize(owner, sc_reader, storage_key, can_gc).is_ok() {
if let Some(blobs) = &sc_reader.blobs {
let blob = blobs
.get(&storage_key)
.expect("No blob found at storage key.");
Expand All @@ -90,9 +86,9 @@ unsafe fn write_blob(
owner: &GlobalScope,
blob: DomRoot<Blob>,
w: *mut JSStructuredCloneWriter,
sc_holder: &mut StructuredDataHolder,
sc_writer: &mut StructuredDataWriter,
) -> bool {
if let Ok(storage_key) = blob.serialize(sc_holder) {
if let Ok(storage_key) = blob.serialize(sc_writer) {
assert!(JS_WriteUint32Pair(
w,
StructuredCloneTags::DomBlob as u32,
Expand Down Expand Up @@ -133,7 +129,7 @@ unsafe extern "C" fn read_callback(
return read_blob(
&GlobalScope::from_context(cx, InRealm::Already(&in_realm_proof)),
r,
&mut *(closure as *mut StructuredDataHolder),
&mut *(closure as *mut StructuredDataReader),
CanGc::note(),
);
}
Expand All @@ -153,7 +149,7 @@ unsafe extern "C" fn write_callback(
&GlobalScope::from_context(cx, InRealm::Already(&in_realm_proof)),
blob,
w,
&mut *(closure as *mut StructuredDataHolder),
&mut *(closure as *mut StructuredDataWriter),
);
}
false
Expand All @@ -170,12 +166,12 @@ unsafe extern "C" fn read_transfer_callback(
return_object: RawMutableHandleObject,
) -> bool {
if tag == StructuredCloneTags::MessagePort as u32 {
let sc_holder = &mut *(closure as *mut StructuredDataHolder);
let sc_reader = &mut *(closure as *mut StructuredDataReader);
let in_realm_proof = AlreadyInRealm::assert_for_cx(SafeJSContext::from_ptr(cx));
let owner = GlobalScope::from_context(cx, InRealm::Already(&in_realm_proof));
if <MessagePort as Transferable>::transfer_receive(
&owner,
sc_holder,
sc_reader,
extra_data,
return_object,
)
Expand All @@ -200,8 +196,8 @@ unsafe extern "C" fn write_transfer_callback(
if let Ok(port) = root_from_object::<MessagePort>(*obj, cx) {
*tag = StructuredCloneTags::MessagePort as u32;
*ownership = TransferableOwnership::SCTAG_TMO_CUSTOM;
let sc_holder = &mut *(closure as *mut StructuredDataHolder);
if let Ok(data) = port.transfer(sc_holder) {
let sc_writer = &mut *(closure as *mut StructuredDataWriter);
if let Ok(data) = port.transfer(sc_writer) {
*extra_data = data;
return true;
}
Expand Down Expand Up @@ -257,31 +253,30 @@ static STRUCTURED_CLONE_CALLBACKS: JSStructuredCloneCallbacks = JSStructuredClon
sabCloned: Some(sab_cloned_callback),
};

/// A data holder for results from, and inputs to, structured-data read/write operations.
/// Reader and writer structs for results from, and inputs to, structured-data read/write operations.
/// <https://html.spec.whatwg.org/multipage/#safe-passing-of-structured-data>
pub enum StructuredDataHolder {
Read {
/// A map of deserialized blobs, stored temporarily here to keep them rooted.
blobs: Option<HashMap<StorageKey, DomRoot<Blob>>>,
/// A vec of transfer-received DOM ports,
/// to be made available to script through a message event.
message_ports: Option<Vec<DomRoot<MessagePort>>>,
/// A map of port implementations,
/// used as part of the "transfer-receiving" steps of ports,
/// to produce the DOM ports stored in `message_ports` above.
port_impls: Option<HashMap<MessagePortId, MessagePortImpl>>,
/// A map of blob implementations,
/// used as part of the "deserialize" steps of blobs,
/// to produce the DOM blobs stored in `blobs` above.
blob_impls: Option<HashMap<BlobId, BlobImpl>>,
},
/// A data holder for transferred and serialized objects.
Write {
/// Transferred ports.
ports: Option<HashMap<MessagePortId, MessagePortImpl>>,
/// Serialized blobs.
blobs: Option<HashMap<BlobId, BlobImpl>>,
},
pub struct StructuredDataReader {
/// A map of deserialized blobs, stored temporarily here to keep them rooted.
pub blobs: Option<HashMap<StorageKey, DomRoot<Blob>>>,
/// A vec of transfer-received DOM ports,
/// to be made available to script through a message event.
pub message_ports: Option<Vec<DomRoot<MessagePort>>>,
/// A map of port implementations,
/// used as part of the "transfer-receiving" steps of ports,
/// to produce the DOM ports stored in `message_ports` above.
pub port_impls: Option<HashMap<MessagePortId, MessagePortImpl>>,
/// A map of blob implementations,
/// used as part of the "deserialize" steps of blobs,
/// to produce the DOM blobs stored in `blobs` above.
pub blob_impls: Option<HashMap<BlobId, BlobImpl>>,
}

/// A data holder for transferred and serialized objects.
pub struct StructuredDataWriter {
/// Transferred ports.
pub ports: Option<HashMap<MessagePortId, MessagePortImpl>>,
/// Serialized blobs.
pub blobs: Option<HashMap<BlobId, BlobImpl>>,
}

/// Writes a structured clone. Returns a `DataClone` error if that fails.
Expand All @@ -295,11 +290,11 @@ pub fn write(
if let Some(transfer) = transfer {
transfer.to_jsval(*cx, val.handle_mut());
}
let mut sc_holder = StructuredDataHolder::Write {
let mut sc_writer = StructuredDataWriter {
ports: None,
blobs: None,
};
let sc_holder_ptr = &mut sc_holder as *mut _;
let sc_writer_ptr = &mut sc_writer as *mut _;

let scbuf = NewJSAutoStructuredCloneBuffer(
StructuredCloneScope::DifferentProcess,
Expand All @@ -317,7 +312,7 @@ pub fn write(
StructuredCloneScope::DifferentProcess,
&policy,
&STRUCTURED_CLONE_CALLBACKS,
sc_holder_ptr as *mut raw::c_void,
sc_writer_ptr as *mut raw::c_void,
val.handle(),
);
if !result {
Expand All @@ -332,15 +327,10 @@ pub fn write(

DeleteJSAutoStructuredCloneBuffer(scbuf);

let (mut blob_impls, mut port_impls) = match sc_holder {
StructuredDataHolder::Write { blobs, ports } => (blobs, ports),
_ => panic!("Unexpected variant of StructuredDataHolder"),
};

let data = StructuredSerializedData {
serialized: data,
ports: port_impls.take(),
blobs: blob_impls.take(),
ports: sc_writer.ports.take(),
blobs: sc_writer.blobs.take(),
};

Ok(data)
Expand All @@ -356,13 +346,13 @@ pub fn read(
) -> Result<Vec<DomRoot<MessagePort>>, ()> {
let cx = GlobalScope::get_cx();
let _ac = enter_realm(global);
let mut sc_holder = StructuredDataHolder::Read {
let mut sc_reader = StructuredDataReader {
blobs: None,
message_ports: None,
port_impls: data.ports.take(),
blob_impls: data.blobs.take(),
};
let sc_holder_ptr = &mut sc_holder as *mut _;
let sc_reader_ptr = &mut sc_reader as *mut _;
unsafe {
let scbuf = NewJSAutoStructuredCloneBuffer(
StructuredCloneScope::DifferentProcess,
Expand All @@ -387,25 +377,16 @@ pub fn read(
allowSharedMemoryObjects_: false,
},
&STRUCTURED_CLONE_CALLBACKS,
sc_holder_ptr as *mut raw::c_void,
sc_reader_ptr as *mut raw::c_void,
);

DeleteJSAutoStructuredCloneBuffer(scbuf);

if result {
let (mut message_ports, port_impls) = match sc_holder {
StructuredDataHolder::Read {
message_ports,
port_impls,
..
} => (message_ports, port_impls),
_ => panic!("Unexpected variant of StructuredDataHolder"),
};

// Any transfer-received port-impls should have been taken out.
assert!(port_impls.is_none());
assert!(sc_reader.port_impls.is_none());

match message_ports.take() {
match sc_reader.message_ports.take() {
Some(ports) => return Ok(ports),
None => return Ok(Vec::with_capacity(0)),
}
Expand Down
6 changes: 3 additions & 3 deletions components/script/dom/bindings/transferable.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,14 +8,14 @@
use js::jsapi::MutableHandleObject;

use crate::dom::bindings::reflector::DomObject;
use crate::dom::bindings::structuredclone::StructuredDataHolder;
use crate::dom::bindings::structuredclone::{StructuredDataReader, StructuredDataWriter};
use crate::dom::globalscope::GlobalScope;

pub trait Transferable: DomObject {
fn transfer(&self, sc_holder: &mut StructuredDataHolder) -> Result<u64, ()>;
fn transfer(&self, sc_writer: &mut StructuredDataWriter) -> Result<u64, ()>;
fn transfer_receive(
owner: &GlobalScope,
sc_holder: &mut StructuredDataHolder,
sc_reader: &mut StructuredDataReader,
extra_data: u64,
return_object: MutableHandleObject,
) -> Result<(), ()>;
Expand Down
27 changes: 8 additions & 19 deletions components/script/dom/blob.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@ use crate::dom::bindings::reflector::{reflect_dom_object_with_proto, DomObject,
use crate::dom::bindings::root::DomRoot;
use crate::dom::bindings::serializable::{Serializable, StorageKey};
use crate::dom::bindings::str::DOMString;
use crate::dom::bindings::structuredclone::StructuredDataHolder;
use crate::dom::bindings::structuredclone::{StructuredDataReader, StructuredDataWriter};
use crate::dom::globalscope::GlobalScope;
use crate::dom::promise::Promise;
use crate::dom::readablestream::ReadableStream;
Expand Down Expand Up @@ -93,12 +93,7 @@ impl Blob {

impl Serializable for Blob {
/// <https://w3c.github.io/FileAPI/#ref-for-serialization-steps>
fn serialize(&self, sc_holder: &mut StructuredDataHolder) -> Result<StorageKey, ()> {
let blob_impls = match sc_holder {
StructuredDataHolder::Write { blobs, .. } => blobs,
_ => panic!("Unexpected variant of StructuredDataHolder"),
};

fn serialize(&self, sc_writer: &mut StructuredDataWriter) -> Result<StorageKey, ()> {
let blob_id = self.blob_id;

// 1. Get a clone of the blob impl.
Expand All @@ -108,7 +103,7 @@ impl Serializable for Blob {
let new_blob_id = blob_impl.blob_id();

// 2. Store the object at a given key.
let blobs = blob_impls.get_or_insert_with(HashMap::new);
let blobs = sc_writer.blobs.get_or_insert_with(HashMap::new);
blobs.insert(new_blob_id, blob_impl);

let PipelineNamespaceId(name_space) = new_blob_id.namespace_id;
Expand All @@ -130,7 +125,7 @@ impl Serializable for Blob {
/// <https://w3c.github.io/FileAPI/#ref-for-deserialization-steps>
fn deserialize(
owner: &GlobalScope,
sc_holder: &mut StructuredDataHolder,
sc_reader: &mut StructuredDataReader,
storage_key: StorageKey,
can_gc: CanGc,
) -> Result<(), ()> {
Expand All @@ -145,27 +140,21 @@ impl Serializable for Blob {
index,
};

let (blobs, blob_impls) = match sc_holder {
StructuredDataHolder::Read {
blobs, blob_impls, ..
} => (blobs, blob_impls),
_ => panic!("Unexpected variant of StructuredDataHolder"),
};

// 2. Get the transferred object from its storage, using the key.
let blob_impls_map = blob_impls
let blob_impls_map = sc_reader
.blob_impls
.as_mut()
.expect("The SC holder does not have any blob impls");
let blob_impl = blob_impls_map
.remove(&id)
.expect("No blob to be deserialized found.");
if blob_impls_map.is_empty() {
*blob_impls = None;
sc_reader.blob_impls = None;
}

let deserialized_blob = Blob::new(owner, blob_impl, can_gc);

let blobs = blobs.get_or_insert_with(HashMap::new);
let blobs = sc_reader.blobs.get_or_insert_with(HashMap::new);
blobs.insert(storage_key, deserialized_blob);

Ok(())
Expand Down
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