Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 313 insertions, 0 deletions

diff --git a/third_party/rust/libloading-0.5.2/src/os/windows/mod.rs b/third_party/rust/libloading-0.5.2/src/os/windows/mod.rs
new file mode 100644
index 0000000000..8157eaba1d
--- /dev/null
+++ b/third_party/rust/libloading-0.5.2/src/os/windows/mod.rs
@@ -0,0 +1,313 @@
+extern crate winapi;
+use self::winapi::shared::minwindef::{WORD, DWORD, HMODULE, FARPROC};
+use self::winapi::shared::ntdef::WCHAR;
+use self::winapi::shared::winerror;
+use self::winapi::um::{errhandlingapi, libloaderapi};
+
+use util::{ensure_compatible_types, cstr_cow_from_bytes};
+
+use std::ffi::{OsStr, OsString};
+use std::{fmt, io, marker, mem, ptr};
+use std::os::windows::ffi::{OsStrExt, OsStringExt};
+use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering};
+
+
+/// A platform-specific equivalent of the cross-platform `Library`.
+pub struct Library(HMODULE);
+
+unsafe impl Send for Library {}
+// Now, this is sort-of-tricky. MSDN documentation does not really make any claims as to safety of
+// the Win32 APIs. Sadly, whomever I asked, even current and former Microsoft employees, couldn’t
+// say for sure, whether the Win32 APIs used to implement `Library` are thread-safe or not.
+//
+// My investigation ended up with a question about thread-safety properties of the API involved
+// being sent to an internal (to MS) general question mailing-list. The conclusion of the mail is
+// as such:
+//
+// * Nobody inside MS (at least out of all the people who have seen the question) knows for
+//   sure either;
+// * However, the general consensus between MS developers is that one can rely on the API being
+//   thread-safe. In case it is not thread-safe it should be considered a bug on the Windows
+//   part. (NB: bugs filled at https://connect.microsoft.com/ against Windows Server)
+unsafe impl Sync for Library {}
+
+impl Library {
+    /// Find and load a shared library (module).
+    ///
+    /// Corresponds to `LoadLibraryW(filename)`.
+    #[inline]
+    pub fn new<P: AsRef<OsStr>>(filename: P) -> ::Result<Library> {
+        let wide_filename: Vec<u16> = filename.as_ref().encode_wide().chain(Some(0)).collect();
+        let _guard = ErrorModeGuard::new();
+
+        let ret = with_get_last_error(|| {
+            // Make sure no winapi calls as a result of drop happen inside this closure, because
+            // otherwise that might change the return value of the GetLastError.
+            let handle = unsafe { libloaderapi::LoadLibraryW(wide_filename.as_ptr()) };
+            if handle.is_null()  {
+                None
+            } else {
+                Some(Library(handle))
+            }
+        }).map_err(|e| e.unwrap_or_else(||
+            panic!("LoadLibraryW failed but GetLastError did not report the error")
+        ));
+
+        drop(wide_filename); // Drop wide_filename here to ensure it doesn’t get moved and dropped
+                             // inside the closure by mistake. See comment inside the closure.
+        ret
+    }
+
+    /// Get a pointer to function or static variable by symbol name.
+    ///
+    /// The `symbol` may not contain any null bytes, with an exception of last byte. A null
+    /// terminated `symbol` may avoid a string allocation in some cases.
+    ///
+    /// Symbol is interpreted as-is; no mangling is done. This means that symbols like `x::y` are
+    /// most likely invalid.
+    ///
+    /// ## Unsafety
+    ///
+    /// Pointer to a value of arbitrary type is returned. Using a value with wrong type is
+    /// undefined.
+    pub unsafe fn get<T>(&self, symbol: &[u8]) -> ::Result<Symbol<T>> {
+        ensure_compatible_types::<T, FARPROC>();
+        let symbol = try!(cstr_cow_from_bytes(symbol));
+        with_get_last_error(|| {
+            let symbol = libloaderapi::GetProcAddress(self.0, symbol.as_ptr());
+            if symbol.is_null() {
+                None
+            } else {
+                Some(Symbol {
+                    pointer: symbol,
+                    pd: marker::PhantomData
+                })
+            }
+        }).map_err(|e| e.unwrap_or_else(||
+            panic!("GetProcAddress failed but GetLastError did not report the error")
+        ))
+    }
+
+    /// Get a pointer to function or static variable by ordinal number.
+    ///
+    /// ## Unsafety
+    ///
+    /// Pointer to a value of arbitrary type is returned. Using a value with wrong type is
+    /// undefined.
+    pub unsafe fn get_ordinal<T>(&self, ordinal: WORD) -> ::Result<Symbol<T>> {
+        ensure_compatible_types::<T, FARPROC>();
+        with_get_last_error(|| {
+            let ordinal = ordinal as usize as *mut _;
+            let symbol = libloaderapi::GetProcAddress(self.0, ordinal);
+            if symbol.is_null() {
+                None
+            } else {
+                Some(Symbol {
+                    pointer: symbol,
+                    pd: marker::PhantomData
+                })
+            }
+        }).map_err(|e| e.unwrap_or_else(||
+            panic!("GetProcAddress failed but GetLastError did not report the error")
+        ))
+    }
+
+    /// Convert the `Library` to a raw handle.
+    pub fn into_raw(self) -> HMODULE {
+        let handle = self.0;
+        mem::forget(self);
+        handle
+    }
+
+    /// Convert a raw handle to a `Library`.
+    ///
+    /// ## Unsafety
+    ///
+    /// The handle shall be a result of a successful call of `LoadLibraryW` or a
+    /// handle previously returned by the `Library::into_raw` call.
+    pub unsafe fn from_raw(handle: HMODULE) -> Library {
+        Library(handle)
+    }
+}
+
+impl Drop for Library {
+    fn drop(&mut self) {
+        with_get_last_error(|| {
+            if unsafe { libloaderapi::FreeLibrary(self.0) == 0 } {
+                None
+            } else {
+                Some(())
+            }
+        }).unwrap()
+    }
+}
+
+impl fmt::Debug for Library {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        unsafe {
+            let mut buf: [WCHAR; 1024] = mem::uninitialized();
+            let len = libloaderapi::GetModuleFileNameW(self.0,
+                                                   (&mut buf[..]).as_mut_ptr(), 1024) as usize;
+            if len == 0 {
+                f.write_str(&format!("Library@{:p}", self.0))
+            } else {
+                let string: OsString = OsString::from_wide(&buf[..len]);
+                f.write_str(&format!("Library@{:p} from {:?}", self.0, string))
+            }
+        }
+    }
+}
+
+/// Symbol from a library.
+///
+/// A major difference compared to the cross-platform `Symbol` is that this does not ensure the
+/// `Symbol` does not outlive `Library` it comes from.
+pub struct Symbol<T> {
+    pointer: FARPROC,
+    pd: marker::PhantomData<T>
+}
+
+impl<T> Symbol<T> {
+    /// Convert the loaded Symbol into a handle.
+    pub fn into_raw(self) -> FARPROC {
+        let pointer = self.pointer;
+        mem::forget(self);
+        pointer
+    }
+}
+
+impl<T> Symbol<Option<T>> {
+    /// Lift Option out of the symbol.
+    pub fn lift_option(self) -> Option<Symbol<T>> {
+        if self.pointer.is_null() {
+            None
+        } else {
+            Some(Symbol {
+                pointer: self.pointer,
+                pd: marker::PhantomData,
+            })
+        }
+    }
+}
+
+unsafe impl<T: Send> Send for Symbol<T> {}
+unsafe impl<T: Sync> Sync for Symbol<T> {}
+
+impl<T> Clone for Symbol<T> {
+    fn clone(&self) -> Symbol<T> {
+        Symbol { ..*self }
+    }
+}
+
+impl<T> ::std::ops::Deref for Symbol<T> {
+    type Target = T;
+    fn deref(&self) -> &T {
+        unsafe {
+            // Additional reference level for a dereference on `deref` return value.
+            mem::transmute(&self.pointer)
+        }
+    }
+}
+
+impl<T> fmt::Debug for Symbol<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.write_str(&format!("Symbol@{:p}", self.pointer))
+    }
+}
+
+
+static USE_ERRORMODE: AtomicBool = ATOMIC_BOOL_INIT;
+struct ErrorModeGuard(DWORD);
+
+impl ErrorModeGuard {
+    fn new() -> Option<ErrorModeGuard> {
+        const SEM_FAILCE: DWORD = 1;
+        unsafe {
+            if !USE_ERRORMODE.load(Ordering::Acquire) {
+                let mut previous_mode = 0;
+                let success = errhandlingapi::SetThreadErrorMode(SEM_FAILCE, &mut previous_mode) != 0;
+                if !success && errhandlingapi::GetLastError() == winerror::ERROR_CALL_NOT_IMPLEMENTED {
+                    USE_ERRORMODE.store(true, Ordering::Release);
+                } else if !success {
+                    // SetThreadErrorMode failed with some other error? How in the world is it
+                    // possible for what is essentially a simple variable swap to fail?
+                    // For now we just ignore the error -- the worst that can happen here is
+                    // the previous mode staying on and user seeing a dialog error on older Windows
+                    // machines.
+                    return None;
+                } else if previous_mode == SEM_FAILCE {
+                    return None;
+                } else {
+                    return Some(ErrorModeGuard(previous_mode));
+                }
+            }
+            match errhandlingapi::SetErrorMode(SEM_FAILCE) {
+                SEM_FAILCE => {
+                    // This is important to reduce racy-ness when this library is used on multiple
+                    // threads. In particular this helps with following race condition:
+                    //
+                    // T1: SetErrorMode(SEM_FAILCE)
+                    // T2: SetErrorMode(SEM_FAILCE)
+                    // T1: SetErrorMode(old_mode) # not SEM_FAILCE
+                    // T2: SetErrorMode(SEM_FAILCE) # restores to SEM_FAILCE on drop
+                    //
+                    // This is still somewhat racy in a sense that T1 might restore the error
+                    // mode before T2 finishes loading the library, but that is less of a
+                    // concern – it will only end up in end user seeing a dialog.
+                    //
+                    // Also, SetErrorMode itself is probably not an atomic operation.
+                    None
+                }
+                a => Some(ErrorModeGuard(a))
+            }
+        }
+    }
+}
+
+impl Drop for ErrorModeGuard {
+    fn drop(&mut self) {
+        unsafe {
+            if !USE_ERRORMODE.load(Ordering::Relaxed) {
+                errhandlingapi::SetThreadErrorMode(self.0, ptr::null_mut());
+            } else {
+                errhandlingapi::SetErrorMode(self.0);
+            }
+        }
+    }
+}
+
+fn with_get_last_error<T, F>(closure: F) -> Result<T, Option<io::Error>>
+where F: FnOnce() -> Option<T> {
+    closure().ok_or_else(|| {
+        let error = unsafe { errhandlingapi::GetLastError() };
+        if error == 0 {
+            None
+        } else {
+            Some(io::Error::from_raw_os_error(error as i32))
+        }
+    })
+}
+
+#[test]
+fn works_getlasterror() {
+    let lib = Library::new("kernel32.dll").unwrap();
+    let gle: Symbol<unsafe extern "system" fn() -> DWORD> = unsafe {
+        lib.get(b"GetLastError").unwrap()
+    };
+    unsafe {
+        errhandlingapi::SetLastError(42);
+        assert_eq!(errhandlingapi::GetLastError(), gle())
+    }
+}
+
+#[test]
+fn works_getlasterror0() {
+    let lib = Library::new("kernel32.dll").unwrap();
+    let gle: Symbol<unsafe extern "system" fn() -> DWORD> = unsafe {
+        lib.get(b"GetLastError\0").unwrap()
+    };
+    unsafe {
+        errhandlingapi::SetLastError(42);
+        assert_eq!(errhandlingapi::GetLastError(), gle())
+    }
+}