1 files changed, 102 insertions, 0 deletions
diff --git a/js/rust/src/sc.rs b/js/rust/src/sc.rs
new file mode 100644
index 0000000000..590c87b421
--- /dev/null
+++ b/js/rust/src/sc.rs
@@ -0,0 +1,102 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+//! Nicer, Rust-y APIs for structured cloning.
+
+use glue;
+use jsapi;
+use rust::Runtime;
+use std::ptr;
+
+/// An RAII owned buffer for structured cloning into and out of.
+pub struct StructuredCloneBuffer {
+    raw: *mut jsapi::JSAutoStructuredCloneBuffer,
+}
+
+impl StructuredCloneBuffer {
+    /// Construct a new `StructuredCloneBuffer`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the underlying JSAPI calls fail.
+    pub fn new(
+        scope: jsapi::JS::StructuredCloneScope,
+        callbacks: &jsapi::JSStructuredCloneCallbacks,
+    ) -> StructuredCloneBuffer {
+        let raw = unsafe { glue::NewJSAutoStructuredCloneBuffer(scope, callbacks) };
+        assert!(!raw.is_null());
+        StructuredCloneBuffer { raw: raw }
+    }
+
+    /// Get the raw `*mut JSStructuredCloneData` owned by this buffer.
+    pub fn data(&self) -> *mut jsapi::JSStructuredCloneData {
+        unsafe { &mut (*self.raw).data_ }
+    }
+
+    /// Copy this buffer's data into a vec.
+    pub fn copy_to_vec(&self) -> Vec<u8> {
+        let len = unsafe { glue::GetLengthOfJSStructuredCloneData(self.data()) };
+        let mut vec = Vec::with_capacity(len);
+        unsafe {
+            glue::CopyJSStructuredCloneData(self.data(), vec.as_mut_ptr());
+        }
+        vec
+    }
+
+    /// Read a JS value out of this buffer.
+    pub fn read(
+        &mut self,
+        vp: jsapi::JS::MutableHandleValue,
+        callbacks: &jsapi::JSStructuredCloneCallbacks,
+    ) -> Result<(), ()> {
+        if unsafe {
+            (*self.raw).read(
+                Runtime::get(),
+                vp,
+                &jsapi::JS::CloneDataPolicy {
+                    allowIntraClusterClonableSharedObjects_: false,
+                    allowSharedMemoryObjects_: false,
+                },
+                callbacks,
+                ptr::null_mut(),
+            )
+        } {
+            Ok(())
+        } else {
+            Err(())
+        }
+    }
+
+    /// Write a JS value into this buffer.
+    pub fn write(
+        &mut self,
+        v: jsapi::JS::HandleValue,
+        callbacks: &jsapi::JSStructuredCloneCallbacks,
+    ) -> Result<(), ()> {
+        if unsafe { (*self.raw).write(Runtime::get(), v, callbacks, ptr::null_mut()) } {
+            Ok(())
+        } else {
+            Err(())
+        }
+    }
+
+    /// Copy the given slice into this buffer.
+    pub fn write_bytes(&mut self, bytes: &[u8]) -> Result<(), ()> {
+        let len = bytes.len();
+        let src = bytes.as_ptr();
+        if unsafe { glue::WriteBytesToJSStructuredCloneData(src, len, self.data()) } {
+            Ok(())
+        } else {
+            Err(())
+        }
+    }
+}
+
+impl Drop for StructuredCloneBuffer {
+    fn drop(&mut self) {
+        unsafe {
+            glue::DeleteJSAutoStructuredCloneBuffer(self.raw);
+        }
+    }
+}