1 files changed, 157 insertions, 0 deletions
diff --git a/third_party/rust/cc/src/windows/com.rs b/third_party/rust/cc/src/windows/com.rs
new file mode 100644
index 0000000000..e81bb1d3c3
--- /dev/null
+++ b/third_party/rust/cc/src/windows/com.rs
@@ -0,0 +1,157 @@
+// Copyright © 2017 winapi-rs developers
+// Licensed under the Apache License, Version 2.0
+// <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your option.
+// All files in the project carrying such notice may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(unused)]
+
+use crate::windows::{
+    winapi::{IUnknown, Interface},
+    windows_sys::{
+        CoInitializeEx, SysFreeString, SysStringLen, BSTR, COINIT_MULTITHREADED, HRESULT, S_FALSE,
+        S_OK,
+    },
+};
+use std::{
+    convert::TryInto,
+    ffi::{OsStr, OsString},
+    mem::ManuallyDrop,
+    ops::Deref,
+    os::windows::ffi::{OsStrExt, OsStringExt},
+    ptr::{null, null_mut},
+    slice::from_raw_parts,
+};
+
+pub fn initialize() -> Result<(), HRESULT> {
+    let err = unsafe { CoInitializeEx(null(), COINIT_MULTITHREADED.try_into().unwrap()) };
+    if err != S_OK && err != S_FALSE {
+        // S_FALSE just means COM is already initialized
+        Err(err)
+    } else {
+        Ok(())
+    }
+}
+
+pub struct ComPtr<T>(*mut T)
+where
+    T: Interface;
+impl<T> ComPtr<T>
+where
+    T: Interface,
+{
+    /// Creates a `ComPtr` to wrap a raw pointer.
+    /// It takes ownership over the pointer which means it does __not__ call `AddRef`.
+    /// `T` __must__ be a COM interface that inherits from `IUnknown`.
+    pub unsafe fn from_raw(ptr: *mut T) -> ComPtr<T> {
+        assert!(!ptr.is_null());
+        ComPtr(ptr)
+    }
+    /// Casts up the inheritance chain
+    pub fn up<U>(self) -> ComPtr<U>
+    where
+        T: Deref<Target = U>,
+        U: Interface,
+    {
+        ComPtr(self.into_raw() as *mut U)
+    }
+    /// Extracts the raw pointer.
+    /// You are now responsible for releasing it yourself.
+    pub fn into_raw(self) -> *mut T {
+        ManuallyDrop::new(self).0
+    }
+    /// For internal use only.
+    fn as_unknown(&self) -> &IUnknown {
+        unsafe { &*(self.0 as *mut IUnknown) }
+    }
+    /// Performs `QueryInterface` fun.
+    pub fn cast<U>(&self) -> Result<ComPtr<U>, i32>
+    where
+        U: Interface,
+    {
+        let mut obj = null_mut();
+        let err = unsafe { self.as_unknown().QueryInterface(&U::uuidof(), &mut obj) };
+        if err < 0 {
+            return Err(err);
+        }
+        Ok(unsafe { ComPtr::from_raw(obj as *mut U) })
+    }
+}
+impl<T> Deref for ComPtr<T>
+where
+    T: Interface,
+{
+    type Target = T;
+    fn deref(&self) -> &T {
+        unsafe { &*self.0 }
+    }
+}
+impl<T> Clone for ComPtr<T>
+where
+    T: Interface,
+{
+    fn clone(&self) -> Self {
+        unsafe {
+            self.as_unknown().AddRef();
+            ComPtr::from_raw(self.0)
+        }
+    }
+}
+impl<T> Drop for ComPtr<T>
+where
+    T: Interface,
+{
+    fn drop(&mut self) {
+        unsafe {
+            self.as_unknown().Release();
+        }
+    }
+}
+pub struct BStr(BSTR);
+impl BStr {
+    pub unsafe fn from_raw(s: BSTR) -> BStr {
+        BStr(s)
+    }
+    pub fn to_osstring(&self) -> OsString {
+        let len = unsafe { SysStringLen(self.0) };
+        let slice = unsafe { from_raw_parts(self.0, len as usize) };
+        OsStringExt::from_wide(slice)
+    }
+}
+impl Drop for BStr {
+    fn drop(&mut self) {
+        unsafe { SysFreeString(self.0) };
+    }
+}
+
+pub trait ToWide {
+    fn to_wide(&self) -> Vec<u16>;
+    fn to_wide_null(&self) -> Vec<u16>;
+}
+impl<T> ToWide for T
+where
+    T: AsRef<OsStr>,
+{
+    fn to_wide(&self) -> Vec<u16> {
+        self.as_ref().encode_wide().collect()
+    }
+    fn to_wide_null(&self) -> Vec<u16> {
+        self.as_ref().encode_wide().chain(Some(0)).collect()
+    }
+}
+pub trait FromWide
+where
+    Self: Sized,
+{
+    fn from_wide(wide: &[u16]) -> Self;
+    fn from_wide_null(wide: &[u16]) -> Self {
+        let len = wide.iter().take_while(|&&c| c != 0).count();
+        Self::from_wide(&wide[..len])
+    }
+}
+impl FromWide for OsString {
+    fn from_wide(wide: &[u16]) -> OsString {
+        OsStringExt::from_wide(wide)
+    }
+}