constellation: Re-split structured data types into separate files (#36615)

In #36364 I moved both serializable and transferable implementations
from the `script_traits` crate into a single file called
`message_ports.rs`. Gregory raised the point that this was a bit of a
inaccurate grouping. This change attempts to fix it according to the
division in the specification.

See [the relevant thread on zulip][thread].

[thread]:
510864104.

Testing: Covered by existing test as this is just code movement.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

components/shared/constellation/structured_data/serializable.rs

@@ -0,0 +1,314 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! This module contains implementations in script that are serializable,
+//! as per <https://html.spec.whatwg.org/multipage/#serializable-objects>.
+//! The implementations are here instead of in script as they need to
+//! be passed through the Constellation.
+
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::path::PathBuf;
+
+use base::id::{BlobId, DomExceptionId, DomPointId};
+use malloc_size_of_derive::MallocSizeOf;
+use net_traits::filemanager_thread::RelativePos;
+use serde::{Deserialize, Serialize};
+use servo_url::ImmutableOrigin;
+use strum::EnumIter;
+use uuid::Uuid;
+
+use super::StructuredSerializedData;
+
+pub(crate) trait BroadcastClone
+where
+    Self: Sized,
+{
+    /// The ID type that uniquely identify each value.
+    type Id: Eq + std::hash::Hash + Copy;
+    /// Clone this value so that it can be reused with a broadcast channel.
+    /// Only return None if cloning is impossible.
+    fn clone_for_broadcast(&self) -> Option<Self>;
+    /// The field from which to clone values.
+    fn source(data: &StructuredSerializedData) -> &Option<HashMap<Self::Id, Self>>;
+    /// The field into which to place cloned values.
+    fn destination(data: &mut StructuredSerializedData) -> &mut Option<HashMap<Self::Id, Self>>;
+}
+
+/// All the DOM interfaces that can be serialized.
+#[derive(Clone, Copy, Debug, EnumIter)]
+pub enum Serializable {
+    /// The `Blob` interface.
+    Blob,
+    /// The `DOMPoint` interface.
+    DomPoint,
+    /// The `DOMPointReadOnly` interface.
+    DomPointReadOnly,
+    /// The `DOMException` interface.
+    DomException,
+}
+
+impl Serializable {
+    pub(super) fn clone_values(
+        &self,
+    ) -> fn(&StructuredSerializedData, &mut StructuredSerializedData) {
+        match self {
+            Serializable::Blob => StructuredSerializedData::clone_all_of_type::<BlobImpl>,
+            Serializable::DomPointReadOnly => {
+                StructuredSerializedData::clone_all_of_type::<DomPoint>
+            },
+            Serializable::DomPoint => StructuredSerializedData::clone_all_of_type::<DomPoint>,
+            Serializable::DomException => {
+                StructuredSerializedData::clone_all_of_type::<DomException>
+            },
+        }
+    }
+}
+
+/// Message for communication between the constellation and a global managing broadcast channels.
+#[derive(Debug, Deserialize, Serialize)]
+pub struct BroadcastMsg {
+    /// The origin of this message.
+    pub origin: ImmutableOrigin,
+    /// The name of the channel.
+    pub channel_name: String,
+    /// A data-holder for serialized data.
+    pub data: StructuredSerializedData,
+}
+
+impl Clone for BroadcastMsg {
+    fn clone(&self) -> BroadcastMsg {
+        BroadcastMsg {
+            data: self.data.clone_for_broadcast(),
+            origin: self.origin.clone(),
+            channel_name: self.channel_name.clone(),
+        }
+    }
+}
+
+/// File-based blob
+#[derive(Debug, Deserialize, MallocSizeOf, Serialize)]
+pub struct FileBlob {
+    #[ignore_malloc_size_of = "Uuid are hard(not really)"]
+    id: Uuid,
+    #[ignore_malloc_size_of = "PathBuf are hard"]
+    name: Option<PathBuf>,
+    cache: RefCell<Option<Vec<u8>>>,
+    size: u64,
+}
+
+impl FileBlob {
+    /// Create a new file blob.
+    pub fn new(id: Uuid, name: Option<PathBuf>, cache: Option<Vec<u8>>, size: u64) -> FileBlob {
+        FileBlob {
+            id,
+            name,
+            cache: RefCell::new(cache),
+            size,
+        }
+    }
+
+    /// Get the size of the file.
+    pub fn get_size(&self) -> u64 {
+        self.size
+    }
+
+    /// Get the cached file data, if any.
+    pub fn get_cache(&self) -> Option<Vec<u8>> {
+        self.cache.borrow().clone()
+    }
+
+    /// Cache data.
+    pub fn cache_bytes(&self, bytes: Vec<u8>) {
+        *self.cache.borrow_mut() = Some(bytes);
+    }
+
+    /// Get the file id.
+    pub fn get_id(&self) -> Uuid {
+        self.id
+    }
+}
+
+impl BroadcastClone for BlobImpl {
+    type Id = BlobId;
+
+    fn source(
+        data: &StructuredSerializedData,
+    ) -> &Option<std::collections::HashMap<Self::Id, Self>> {
+        &data.blobs
+    }
+
+    fn destination(
+        data: &mut StructuredSerializedData,
+    ) -> &mut Option<std::collections::HashMap<Self::Id, Self>> {
+        &mut data.blobs
+    }
+
+    fn clone_for_broadcast(&self) -> Option<Self> {
+        let type_string = self.type_string();
+
+        if let BlobData::Memory(bytes) = self.blob_data() {
+            let blob_clone = BlobImpl::new_from_bytes(bytes.clone(), type_string);
+
+            // Note: we insert the blob at the original id,
+            // otherwise this will not match the storage key as serialized by SM in `serialized`.
+            // The clone has it's own new Id however.
+            return Some(blob_clone);
+        } else {
+            // Not panicking only because this is called from the constellation.
+            log::warn!("Serialized blob not in memory format(should never happen).");
+        }
+        None
+    }
+}
+
+/// The data backing a DOM Blob.
+#[derive(Debug, Deserialize, MallocSizeOf, Serialize)]
+pub struct BlobImpl {
+    /// UUID of the blob.
+    blob_id: BlobId,
+    /// Content-type string
+    type_string: String,
+    /// Blob data-type.
+    blob_data: BlobData,
+    /// Sliced blobs referring to this one.
+    slices: Vec<BlobId>,
+}
+
+/// Different backends of Blob
+#[derive(Debug, Deserialize, MallocSizeOf, Serialize)]
+pub enum BlobData {
+    /// File-based blob, whose content lives in the net process
+    File(FileBlob),
+    /// Memory-based blob, whose content lives in the script process
+    Memory(Vec<u8>),
+    /// Sliced blob, including parent blob-id and
+    /// relative positions of current slicing range,
+    /// IMPORTANT: The depth of tree is only two, i.e. the parent Blob must be
+    /// either File-based or Memory-based
+    Sliced(BlobId, RelativePos),
+}
+
+impl BlobImpl {
+    /// Construct memory-backed BlobImpl
+    pub fn new_from_bytes(bytes: Vec<u8>, type_string: String) -> BlobImpl {
+        let blob_id = BlobId::new();
+        let blob_data = BlobData::Memory(bytes);
+        BlobImpl {
+            blob_id,
+            type_string,
+            blob_data,
+            slices: vec![],
+        }
+    }
+
+    /// Construct file-backed BlobImpl from File ID
+    pub fn new_from_file(file_id: Uuid, name: PathBuf, size: u64, type_string: String) -> BlobImpl {
+        let blob_id = BlobId::new();
+        let blob_data = BlobData::File(FileBlob {
+            id: file_id,
+            name: Some(name),
+            cache: RefCell::new(None),
+            size,
+        });
+        BlobImpl {
+            blob_id,
+            type_string,
+            blob_data,
+            slices: vec![],
+        }
+    }
+
+    /// Construct a BlobImpl from a slice of a parent.
+    pub fn new_sliced(rel_pos: RelativePos, parent: BlobId, type_string: String) -> BlobImpl {
+        let blob_id = BlobId::new();
+        let blob_data = BlobData::Sliced(parent, rel_pos);
+        BlobImpl {
+            blob_id,
+            type_string,
+            blob_data,
+            slices: vec![],
+        }
+    }
+
+    /// Get a clone of the blob-id
+    pub fn blob_id(&self) -> BlobId {
+        self.blob_id
+    }
+
+    /// Get a clone of the type-string
+    pub fn type_string(&self) -> String {
+        self.type_string.clone()
+    }
+
+    /// Get a mutable ref to the data
+    pub fn blob_data(&self) -> &BlobData {
+        &self.blob_data
+    }
+
+    /// Get a mutable ref to the data
+    pub fn blob_data_mut(&mut self) -> &mut BlobData {
+        &mut self.blob_data
+    }
+}
+
+#[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
+/// A serializable version of the DOMPoint/DOMPointReadOnly interface.
+pub struct DomPoint {
+    /// The x coordinate.
+    pub x: f64,
+    /// The y coordinate.
+    pub y: f64,
+    /// The z coordinate.
+    pub z: f64,
+    /// The w coordinate.
+    pub w: f64,
+}
+
+impl BroadcastClone for DomPoint {
+    type Id = DomPointId;
+
+    fn source(
+        data: &StructuredSerializedData,
+    ) -> &Option<std::collections::HashMap<Self::Id, Self>> {
+        &data.points
+    }
+
+    fn destination(
+        data: &mut StructuredSerializedData,
+    ) -> &mut Option<std::collections::HashMap<Self::Id, Self>> {
+        &mut data.points
+    }
+
+    fn clone_for_broadcast(&self) -> Option<Self> {
+        Some(self.clone())
+    }
+}
+
+#[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
+/// A serializable version of the DOMException interface.
+pub struct DomException {
+    pub message: String,
+    pub name: String,
+}
+
+impl BroadcastClone for DomException {
+    type Id = DomExceptionId;
+
+    fn source(
+        data: &StructuredSerializedData,
+    ) -> &Option<std::collections::HashMap<Self::Id, Self>> {
+        &data.exceptions
+    }
+
+    fn destination(
+        data: &mut StructuredSerializedData,
+    ) -> &mut Option<std::collections::HashMap<Self::Id, Self>> {
+        &mut data.exceptions
+    }
+
+    fn clone_for_broadcast(&self) -> Option<Self> {
+        Some(self.clone())
+    }
+}