From 567998c159a66bc8c2c3104e65b105b92234d869 Mon Sep 17 00:00:00 2001
From: Oliver Hamlet <git@ortham.net>
Date: Thu, 20 Mar 2025 22:51:43 +0000
Subject: [PATCH] Fix are_file_paths_equivalent on Windows

Trying to get an exclusive lock on the files was too flaky and also prone to false positives.
---
 Cargo.lock          |  1 +
 Cargo.toml          |  3 +++
 src/archive/find.rs | 48 ++++++++++++++++++++++++---------------------
 3 files changed, 30 insertions(+), 22 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 3ca6a175..3c7e598d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -451,6 +451,7 @@ dependencies = [
  "saphyr-parser",
  "tempfile",
  "unicase",
+ "windows",
 ]
 
 [[package]]
diff --git a/Cargo.toml b/Cargo.toml
index a47617d1..24ab2fcf 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,6 +17,9 @@ saphyr-parser = "0.0.3"
 unicase = "2.8.1"
 rayon = "1.10.0"
 
+[target.'cfg(windows)'.dependencies]
+windows = { version = "0.60.0", features = ["Win32_Storage_FileSystem"] }
+
 [dev-dependencies]
 rstest = "0.25.0"
 rstest_reuse = "0.7.0"
diff --git a/src/archive/find.rs b/src/archive/find.rs
index 7896224e..ae9fb1ac 100644
--- a/src/archive/find.rs
+++ b/src/archive/find.rs
@@ -1,7 +1,4 @@
-use std::{
-    fs::OpenOptions,
-    path::{Path, PathBuf},
-};
+use std::path::{Path, PathBuf};
 
 use crate::{GameType, game::GameCache, plugin::has_ascii_extension};
 
@@ -136,32 +133,39 @@ fn are_file_paths_equivalent(lhs: &Path, rhs: &Path) -> bool {
         return true;
     }
 
-    // See <https://learn.microsoft.com/en-us/windows/win32/debug/system-error-codes--0-499->
-    // Or windows::Win32::Foundation::ERROR_SHARING_VIOLATION in the "windows" crate.
-    const ERROR_SHARING_VIOLATION: i32 = 32;
-    use std::os::windows::fs::OpenOptionsExt;
+    use std::fs::File;
+    use std::os::windows::io::AsRawHandle;
+    use windows::Win32::{
+        Foundation::HANDLE,
+        Storage::FileSystem::{BY_HANDLE_FILE_INFORMATION, GetFileInformationByHandle},
+    };
 
-    let lhs_file = match OpenOptions::new().read(true).share_mode(0).open(lhs) {
+    let lhs_file = match File::open(lhs) {
         Ok(f) => f,
         Err(_) => return false,
     };
 
-    let result = match OpenOptions::new().read(true).share_mode(0).open(rhs) {
-        Ok(_) => {
-            false
-        }
-        Err(e) => {
-            if let Some(error_code) = e.raw_os_error() {
-                error_code == ERROR_SHARING_VIOLATION
-            } else {
-                false
-            }
-        }
+    let rhs_file = match File::open(rhs) {
+        Ok(f) => f,
+        Err(_) => return false,
     };
 
-    drop(lhs_file);
+    let mut lhs_info = BY_HANDLE_FILE_INFORMATION::default();
+    let mut rhs_info = BY_HANDLE_FILE_INFORMATION::default();
+    // SAFETY: This is safe because the file handles and the info struct pointers are all valid until this function exits.
+    unsafe {
+        if GetFileInformationByHandle(HANDLE(lhs_file.as_raw_handle()), &mut lhs_info).is_err() {
+            return false;
+        }
 
-    result
+        if GetFileInformationByHandle(HANDLE(rhs_file.as_raw_handle()), &mut rhs_info).is_err() {
+            return false;
+        }
+    }
+
+    lhs_info.dwVolumeSerialNumber == rhs_info.dwVolumeSerialNumber
+        && lhs_info.nFileIndexHigh == rhs_info.nFileIndexHigh
+        && lhs_info.nFileIndexLow == rhs_info.nFileIndexLow
 }
 
 #[cfg(not(windows))]