implement std.os.deleteFile for windows

Author: andrewrk

std/os/index.zig

@@ -577,6 +577,35 @@ pub fn atomicSymLink(allocator: &Allocator, existing_path: []const u8, new_path:
 }
 
 pub fn deleteFile(allocator: &Allocator, file_path: []const u8) -> %void {
+    if (builtin.os == Os.windows) {
+        return deleteFileWindows(allocator, file_path);
+    } else {
+        return deleteFilePosix(allocator, file_path);
+    }
+}
+
+error FileNotFound;
+error AccessDenied;
+
+pub fn deleteFileWindows(allocator: &Allocator, file_path: []const u8) -> %void {
+    const buf = %return allocator.alloc(u8, file_path.len + 1);
+    defer allocator.free(buf);
+
+    mem.copy(u8, buf, file_path);
+    buf[file_path.len] = 0;
+
+    if (!windows.DeleteFileA(buf.ptr)) {
+        const err = windows.GetLastError();
+        return switch (err) {
+            windows.ERROR.FILE_NOT_FOUND => error.FileNotFound,
+            windows.ERROR.ACCESS_DENIED => error.AccessDenied,
+            windows.ERROR.FILENAME_EXCED_RANGE, windows.ERROR.INVALID_PARAMETER => error.NameTooLong,
+            else => error.Unexpected,
+        }
+    }
+}
+
+pub fn deleteFilePosix(allocator: &Allocator, file_path: []const u8) -> %void {
     const buf = %return allocator.alloc(u8, file_path.len + 1);
     defer allocator.free(buf);
 

std/os/windows/index.zig

@@ -7,13 +7,15 @@ pub extern "kernel32" stdcallcc fn CryptReleaseContext(hProv: HCRYPTPROV, dwFlag
 
 pub extern "kernel32" stdcallcc fn CryptGenRandom(hProv: HCRYPTPROV, dwLen: DWORD, pbBuffer: &BYTE) -> bool;
 
+pub extern "kernel32" stdcallcc fn DeleteFileA(lpFileName: LPCSTR) -> bool;
+
 pub extern "kernel32" stdcallcc fn ExitProcess(exit_code: UINT) -> noreturn;
 
 pub extern "kernel32" stdcallcc fn GetCommandLine() -> LPTSTR;
 
 pub extern "kernel32" stdcallcc fn GetConsoleMode(in_hConsoleHandle: HANDLE, out_lpMode: &DWORD) -> bool;
 
-pub extern "kernel32" stdcallcc fn GetCurrentDirectoryA(nBufferLength: WORD, lpBuffer: ?LPTSTR) -> DWORD;
+pub extern "kernel32" stdcallcc fn GetCurrentDirectoryA(nBufferLength: WORD, lpBuffer: ?LPSTR) -> DWORD;
 
 /// Retrieves the calling thread's last-error code value. The last-error code is maintained on a per-thread basis.
 /// Multiple threads do not overwrite each other's last-error code.
@@ -68,6 +70,7 @@ pub const HANDLE = &c_void;
 pub const HINSTANCE = &@OpaqueType();
 pub const HCRYPTPROV = ULONG_PTR;
 pub const LPCTSTR = &const TCHAR;
+pub const LPCSTR = &const CHAR;
 pub const LPDWORD = &DWORD;
 pub const LPVOID = &c_void;
 pub const PVOID = &c_void;