1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146

use crate::external_references::ExternalReferences;
use crate::scope::data::ScopeData;
use crate::support::char;
use crate::support::int;
use crate::support::intptr_t;
use crate::Context;
use crate::Isolate;
use crate::Local;
use crate::OwnedIsolate;

use std::borrow::Borrow;
use std::convert::TryFrom;
use std::mem::MaybeUninit;
use std::ops::Deref;

extern "C" {
  fn v8__SnapshotCreator__CONSTRUCT(
    buf: *mut MaybeUninit<SnapshotCreator>,
    external_references: *const intptr_t,
  );
  fn v8__SnapshotCreator__DESTRUCT(this: *mut SnapshotCreator);
  fn v8__SnapshotCreator__GetIsolate(
    this: *mut SnapshotCreator,
  ) -> *mut Isolate;
  fn v8__SnapshotCreator__CreateBlob(
    this: *mut SnapshotCreator,
    function_code_handling: FunctionCodeHandling,
  ) -> StartupData;
  fn v8__SnapshotCreator__SetDefaultContext(
    this: *mut SnapshotCreator,
    context: *const Context,
  );
  fn v8__StartupData__DESTRUCT(this: *mut StartupData);
}

#[repr(C)]
pub struct StartupData {
  data: *const char,
  raw_size: int,
}

impl Deref for StartupData {
  type Target = [u8];
  fn deref(&self) -> &Self::Target {
    let data = self.data as *const u8;
    let len = usize::try_from(self.raw_size).unwrap();
    unsafe { std::slice::from_raw_parts(data, len) }
  }
}

impl AsRef<[u8]> for StartupData {
  fn as_ref(&self) -> &[u8] {
    &**self
  }
}

impl Borrow<[u8]> for StartupData {
  fn borrow(&self) -> &[u8] {
    &**self
  }
}

impl Drop for StartupData {
  fn drop(&mut self) {
    unsafe { v8__StartupData__DESTRUCT(self) }
  }
}

#[repr(C)]
pub enum FunctionCodeHandling {
  Clear,
  Keep,
}

/// Helper class to create a snapshot data blob.
#[repr(C)]
pub struct SnapshotCreator([usize; 1]);

impl SnapshotCreator {
  /// Create and enter an isolate, and set it up for serialization.
  /// The isolate is created from scratch.
  pub fn new(external_references: Option<&'static ExternalReferences>) -> Self {
    let mut snapshot_creator: MaybeUninit<Self> = MaybeUninit::uninit();
    let external_references_ptr = if let Some(er) = external_references {
      er.as_ptr()
    } else {
      std::ptr::null()
    };
    unsafe {
      v8__SnapshotCreator__CONSTRUCT(
        &mut snapshot_creator,
        external_references_ptr,
      );
      snapshot_creator.assume_init()
    }
  }
}

impl Drop for SnapshotCreator {
  fn drop(&mut self) {
    unsafe { v8__SnapshotCreator__DESTRUCT(self) };
  }
}

impl SnapshotCreator {
  /// Set the default context to be included in the snapshot blob.
  /// The snapshot will not contain the global proxy, and we expect one or a
  /// global object template to create one, to be provided upon deserialization.
  pub fn set_default_context<'s>(&mut self, context: Local<'s, Context>) {
    unsafe { v8__SnapshotCreator__SetDefaultContext(self, &*context) };
  }

  /// Creates a snapshot data blob.
  /// This must not be called from within a handle scope.
  pub fn create_blob(
    &mut self,
    function_code_handling: FunctionCodeHandling,
  ) -> Option<StartupData> {
    {
      let isolate = unsafe { &mut *v8__SnapshotCreator__GetIsolate(self) };
      ScopeData::get_root_mut(isolate);
    }
    let blob =
      unsafe { v8__SnapshotCreator__CreateBlob(self, function_code_handling) };
    if blob.data.is_null() {
      debug_assert!(blob.raw_size == 0);
      None
    } else {
      debug_assert!(blob.raw_size > 0);
      Some(blob)
    }
  }

  /// This is marked unsafe because it should be called at most once per
  /// snapshot creator.
  // TODO Because the SnapshotCreator creates its own isolate, we need a way to
  // get an owned handle to it. This is a questionable design which ought to be
  // revisited after the libdeno integration is complete.
  pub unsafe fn get_owned_isolate(&mut self) -> OwnedIsolate {
    let isolate_ptr = v8__SnapshotCreator__GetIsolate(self);
    let mut owned_isolate = OwnedIsolate::new(isolate_ptr);
    ScopeData::new_root(&mut owned_isolate);
    owned_isolate.create_annex(Box::new(()));
    owned_isolate
  }
}