use std::path::Path;
use std::path::PathBuf;
use std::time::Instant;
use crate::ExtModuleLoaderCb;
use crate::Extension;
use crate::JsRuntime;
use crate::RuntimeOptions;
use crate::Snapshot;
pub type CompressionCb = dyn Fn(&mut Vec<u8>, &[u8]);
pub struct CreateSnapshotOptions {
pub cargo_manifest_dir: &'static str,
pub snapshot_path: PathBuf,
pub startup_snapshot: Option<Snapshot>,
pub extensions: Vec<Extension>,
pub compression_cb: Option<Box<CompressionCb>>,
pub snapshot_module_load_cb: Option<ExtModuleLoaderCb>,
}
pub fn create_snapshot(create_snapshot_options: CreateSnapshotOptions) {
let mut mark = Instant::now();
let js_runtime = JsRuntime::new(RuntimeOptions {
will_snapshot: true,
startup_snapshot: create_snapshot_options.startup_snapshot,
extensions: create_snapshot_options.extensions,
snapshot_module_load_cb: create_snapshot_options.snapshot_module_load_cb,
..Default::default()
});
println!(
"JsRuntime for snapshot prepared, took {:#?} ({})",
Instant::now().saturating_duration_since(mark),
create_snapshot_options.snapshot_path.display()
);
mark = Instant::now();
let snapshot = js_runtime.snapshot();
let snapshot_slice: &[u8] = &snapshot;
println!(
"Snapshot size: {}, took {:#?} ({})",
snapshot_slice.len(),
Instant::now().saturating_duration_since(mark),
create_snapshot_options.snapshot_path.display()
);
mark = Instant::now();
let maybe_compressed_snapshot: Box<dyn AsRef<[u8]>> =
if let Some(compression_cb) = create_snapshot_options.compression_cb {
let mut vec = vec![];
vec.extend_from_slice(
&u32::try_from(snapshot.len())
.expect("snapshot larger than 4gb")
.to_le_bytes(),
);
(compression_cb)(&mut vec, snapshot_slice);
println!(
"Snapshot compressed size: {}, took {:#?} ({})",
vec.len(),
Instant::now().saturating_duration_since(mark),
create_snapshot_options.snapshot_path.display()
);
mark = std::time::Instant::now();
Box::new(vec)
} else {
Box::new(snapshot_slice)
};
std::fs::write(
&create_snapshot_options.snapshot_path,
&*maybe_compressed_snapshot,
)
.unwrap();
println!(
"Snapshot written, took: {:#?} ({})",
Instant::now().saturating_duration_since(mark),
create_snapshot_options.snapshot_path.display(),
);
}
pub type FilterFn = Box<dyn Fn(&PathBuf) -> bool>;
pub fn get_js_files(
cargo_manifest_dir: &'static str,
directory: &str,
filter: Option<FilterFn>,
) -> Vec<PathBuf> {
let manifest_dir = Path::new(cargo_manifest_dir);
let mut js_files = std::fs::read_dir(directory)
.unwrap()
.map(|dir_entry| {
let file = dir_entry.unwrap();
manifest_dir.join(file.path())
})
.filter(|path| {
path.extension().unwrap_or_default() == "js"
&& filter.as_ref().map(|filter| filter(path)).unwrap_or(true)
})
.collect::<Vec<PathBuf>>();
js_files.sort();
js_files
}
fn data_error_to_panic(err: v8::DataError) -> ! {
match err {
v8::DataError::BadType { actual, expected } => {
panic!(
"Invalid type for snapshot data: expected {expected}, got {actual}"
);
}
v8::DataError::NoData { expected } => {
panic!("No data for snapshot data: expected {expected}");
}
}
}
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub(crate) enum SnapshotOptions {
Load,
CreateFromExisting,
Create,
None,
}
impl SnapshotOptions {
pub fn loaded(&self) -> bool {
matches!(self, Self::Load | Self::CreateFromExisting)
}
pub fn will_snapshot(&self) -> bool {
matches!(self, Self::Create | Self::CreateFromExisting)
}
pub fn from_bools(snapshot_loaded: bool, will_snapshot: bool) -> Self {
match (snapshot_loaded, will_snapshot) {
(true, true) => Self::CreateFromExisting,
(false, true) => Self::Create,
(true, false) => Self::Load,
(false, false) => Self::None,
}
}
}
pub(crate) struct SnapshottedData {
pub module_map_data: v8::Global<v8::Array>,
pub module_handles: Vec<v8::Global<v8::Module>>,
}
static MODULE_MAP_CONTEXT_DATA_INDEX: usize = 0;
pub(crate) fn get_snapshotted_data(
scope: &mut v8::HandleScope<()>,
context: v8::Local<v8::Context>,
) -> SnapshottedData {
let mut scope = v8::ContextScope::new(scope, context);
let result = scope.get_context_data_from_snapshot_once::<v8::Array>(
MODULE_MAP_CONTEXT_DATA_INDEX,
);
let val = match result {
Ok(v) => v,
Err(err) => data_error_to_panic(err),
};
let next_module_id = {
let info_data: v8::Local<v8::Array> =
val.get_index(&mut scope, 1).unwrap().try_into().unwrap();
info_data.length()
};
let mut module_handles = Vec::with_capacity(next_module_id as usize + 16);
for i in 1..=next_module_id {
match scope.get_context_data_from_snapshot_once::<v8::Module>(i as usize) {
Ok(val) => {
let module_global = v8::Global::new(&mut scope, val);
module_handles.push(module_global);
}
Err(err) => data_error_to_panic(err),
}
}
SnapshottedData {
module_map_data: v8::Global::new(&mut scope, val),
module_handles,
}
}
pub(crate) fn set_snapshotted_data(
scope: &mut v8::HandleScope<()>,
context: v8::Global<v8::Context>,
snapshotted_data: SnapshottedData,
) {
let local_context = v8::Local::new(scope, context);
let local_data = v8::Local::new(scope, snapshotted_data.module_map_data);
let offset = scope.add_context_data(local_context, local_data);
assert_eq!(offset, MODULE_MAP_CONTEXT_DATA_INDEX);
for (index, handle) in snapshotted_data.module_handles.into_iter().enumerate()
{
let module_handle = v8::Local::new(scope, handle);
let offset = scope.add_context_data(local_context, module_handle);
assert_eq!(offset, index + 1);
}
}
pub(crate) fn create_snapshot_creator(
external_refs: &'static v8::ExternalReferences,
maybe_startup_snapshot: Option<Snapshot>,
) -> v8::OwnedIsolate {
if let Some(snapshot) = maybe_startup_snapshot {
match snapshot {
Snapshot::Static(data) => {
v8::Isolate::snapshot_creator_from_existing_snapshot(
data,
Some(external_refs),
)
}
Snapshot::JustCreated(data) => {
v8::Isolate::snapshot_creator_from_existing_snapshot(
data,
Some(external_refs),
)
}
Snapshot::Boxed(data) => {
v8::Isolate::snapshot_creator_from_existing_snapshot(
data,
Some(external_refs),
)
}
}
} else {
v8::Isolate::snapshot_creator(Some(external_refs))
}
}