feat(engine-ecs): add Error::from_system_defined_win32_error fn

2 files changed, 43 insertions, 1 deletions

diff --git a/engine-ecs/Cargo.toml b/engine-ecs/Cargo.toml
index 001cf54..e9ce85c 100644
--- a/engine-ecs/Cargo.toml
+++ b/engine-ecs/Cargo.toml
@@ -21,7 +21,11 @@ vizoxide = { version = "1.0.5", optional = true }
 
 [target.'cfg(windows)'.dependencies.windows-sys]
 version = "0.61.2"
-features = ["Win32_System_Threading"]
+features = [
+	"Win32_System_Threading",
+	"Win32_System_Diagnostics_Debug",
+	"Win32_Foundation"
+]
 
 [target.'cfg(target_os = "linux")'.dependencies.libc]
 version = "0.2.186"
diff --git a/engine-ecs/src/error.rs b/engine-ecs/src/error.rs
index 2654dde..5ce5632 100644
--- a/engine-ecs/src/error.rs
+++ b/engine-ecs/src/error.rs
@@ -44,6 +44,44 @@ impl Error
     {
         Self { inner: self.inner.context(context) }
     }
+
+    /// Retrieves the message text of a system-defined Windows Win32 error code and
+    /// returns it as a `Error`. If this fails (for example if the error code is invalid),
+    /// the returned `Error` contains the error code number.
+    #[cfg(windows)]
+    pub fn from_system_defined_win32_error(error: u32) -> Self
+    {
+        use std::ffi::CStr;
+        use std::ptr::null;
+
+        use windows_sys::Win32::System::Diagnostics::Debug::{
+            FormatMessageA,
+            FORMAT_MESSAGE_FROM_SYSTEM,
+            FORMAT_MESSAGE_IGNORE_INSERTS,
+        };
+
+        let mut buffer = vec![0u8; 256];
+
+        let len = unsafe {
+            FormatMessageA(
+                FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+                null(),
+                error,
+                0,
+                buffer.as_mut_ptr(),
+                (buffer.len() - 1) as u32,
+                null(),
+            )
+        } as usize;
+
+        if len == 0 {
+            return Self::message(format!("Win32 error {error}"));
+        }
+
+        let buf = unsafe { CStr::from_bytes_with_nul_unchecked(&buffer[..len + 1]) };
+
+        Self::message(buf.to_string_lossy().trim().to_owned())
+    }
 }
 
 impl Debug for Error