From e36e1e1fbb35f80850e672eeba51a9ac0ee954d5 Mon Sep 17 00:00:00 2001
From: adumbidiot <nathaniel.daniel23@outlook.com>
Date: Fri, 30 Oct 2020 18:24:19 -0700
Subject: [PATCH] Copy win_delay_load_hook from Neon

---
 napi/Cargo.toml                 |  3 ++
 napi/src/lib.rs                 |  2 +
 napi/src/win_delay_load_hook.rs | 79 +++++++++++++++++++++++++++++++++
 3 files changed, 84 insertions(+)
 create mode 100644 napi/src/win_delay_load_hook.rs

diff --git a/napi/Cargo.toml b/napi/Cargo.toml
index ab9a8357..0628c8fb 100644
--- a/napi/Cargo.toml
+++ b/napi/Cargo.toml
@@ -18,6 +18,9 @@ tokio_rt = ["futures", "tokio", "once_cell"]
 [dependencies]
 napi-sys = {version = "0.4", path = "../sys"}
 
+[target.'cfg(windows)'.dependencies]
+winapi = "0.3.9"
+
 [dependencies.encoding_rs]
 optional = true
 version = "0.8"
diff --git a/napi/src/lib.rs b/napi/src/lib.rs
index 8ce80c4e..442194de 100644
--- a/napi/src/lib.rs
+++ b/napi/src/lib.rs
@@ -110,6 +110,8 @@ mod tokio_rt;
 #[cfg(all(feature = "libuv", napi4))]
 mod uv;
 mod version;
+#[cfg(target_os = "windows")]
+mod win_delay_load_hook;
 
 pub use napi_sys as sys;
 
diff --git a/napi/src/win_delay_load_hook.rs b/napi/src/win_delay_load_hook.rs
new file mode 100644
index 00000000..712cbc54
--- /dev/null
+++ b/napi/src/win_delay_load_hook.rs
@@ -0,0 +1,79 @@
+//! The following directly was copied from [neon][].
+//!
+//! Rust port of [win_delay_load_hook.cc][].
+//!
+//! When the addon tries to load the "node.exe" DLL module, this module gives it the pointer to the
+//! .exe we are running in instead. Typically, that will be the same value. But if the node executable
+//! was renamed, you would not otherwise get the correct DLL.
+//!
+//! [neon]: https://github.com/neon-bindings/neon/blob/5ffa2d282177b63094c46e92b20b8e850d122e65/src/win_delay_load_hook.rs
+//! [win_delay_load_hook.cc]: https://github.com/nodejs/node-gyp/blob/e18a61afc1669d4897e6c5c8a6694f4995a0f4d6/src/win_delay_load_hook.cc
+
+use std::ffi::CStr;
+use std::ptr::null_mut;
+use winapi::shared::minwindef::{BOOL, DWORD, FARPROC, HMODULE, LPVOID};
+use winapi::shared::ntdef::LPCSTR;
+use winapi::um::libloaderapi::GetModuleHandleA;
+
+// Structures hand-copied from
+// https://docs.microsoft.com/en-us/cpp/build/reference/structure-and-constant-definitions
+
+#[repr(C)]
+#[allow(non_snake_case)]
+struct DelayLoadProc {
+  fImportByName: BOOL,
+  // Technically this is `union{LPCSTR; DWORD;}` but we don't access it anyways.
+  szProcName: LPCSTR,
+}
+
+#[repr(C)]
+#[allow(non_snake_case)]
+struct DelayLoadInfo {
+  /// size of structure
+  cb: DWORD,
+  /// raw form of data (everything is there)
+  /// Officially a pointer to ImgDelayDescr but we don't access it.
+  pidd: LPVOID,
+  /// points to address of function to load
+  ppfn: *mut FARPROC,
+  /// name of dll
+  szDll: LPCSTR,
+  /// name or ordinal of procedure
+  dlp: DelayLoadProc,
+  /// the hInstance of the library we have loaded
+  hmodCur: HMODULE,
+  /// the actual function that will be called
+  pfnCur: FARPROC,
+  /// error received (if an error notification)
+  dwLastError: DWORD,
+}
+
+#[allow(non_snake_case)]
+type PfnDliHook = unsafe extern "C" fn(dliNotify: usize, pdli: *const DelayLoadInfo) -> FARPROC;
+
+const HOST_BINARIES: &[&[u8]] = &[b"node.exe", b"electron.exe"];
+
+unsafe extern "C" fn load_exe_hook(event: usize, info: *const DelayLoadInfo) -> FARPROC {
+  if event != 0x01
+  /* dliNotePreLoadLibrary */
+  {
+    return null_mut();
+  }
+
+  let dll_name = CStr::from_ptr((*info).szDll);
+  if !HOST_BINARIES
+    .iter()
+    .any(|&host_name| host_name == dll_name.to_bytes())
+  {
+    return null_mut();
+  }
+
+  let exe_handle = GetModuleHandleA(null_mut());
+
+  // PfnDliHook sometimes has to return a FARPROC, sometimes an HMODULE, but only one
+  // of them could be specified in the header, so we have to cast our HMODULE to that.
+  exe_handle as FARPROC
+}
+
+#[no_mangle]
+static mut __pfnDliNotifyHook2: *mut PfnDliHook = load_exe_hook as *mut PfnDliHook;