Add fallback implementations for Mutex, CondVar and RwLock

- Add fallback implementations for `MovableMutex`

  `MovableMutex`es have two fallback implementations:

  - Critical sections (NT4+ because of
    try_lock/`TryEnterCriticalSection`)
  - CreateMutex handles-based mutex (all Win32)

- Add `MovableRWLock` fallback implementation, falling back to a
  `MovableMutex` if `SRWLock`s are not available
- Add `StaticRWLock`/`StaticMutex` shared fallback implementation. These
  only need the critical section fallback implementation since static
  mutexes don't need/expose `try_lock`. They do, however, need to be
  initialized, so the implementation is based on the old XP-compatible
  `Mutex` impl from before it was removed. Old impl seen here:
  https://github.com/rust-lang/rust/blob/c35007dbbe4846c641b5edad9fddf3f72a5a035a/library/std/src/sys/windows/mutex.rs

  Since the impls for MovableMutex and StaticMutex are now different,
  the `sys_common/mutex.rs` definition of `StaticMutex` and
  `StaticMutexGuard` had to be changed. (Same for `MovableRWLock` and
  `StaticRWLock`)

- Add fallback implementation for `ReentrantMutex` based on
  `CreateMutex` mutexes, as those are reentrant as well.

- Implement `CondVar` fallback based on `CreateEventA`/`PulseEvent`.
  This should be used with extreme caution as it may cause deadlocks.
  See which may cause deadlocks. See [Old New
  Thing](https://devblogs.microsoft.com/oldnewthing/20050105-00/?p=36803)
  and the [MSDN
  docs](https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-pulseevent)
  for more information.

Author: seritools

library/std/src/sys/windows/c.rs

@@ -351,6 +351,56 @@ compat_fn_with_fallback! {
     pub fn GetTempPath2W(bufferlength: u32, buffer: PWSTR) -> u32 {
         GetTempPathW(bufferlength, buffer)
     }
+
+    // >= NT 4
+    // https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-tryentercriticalsection
+    pub fn TryEnterCriticalSection(CriticalSection: *mut CRITICAL_SECTION) -> BOOL {
+        rtabort!("unavailable")
+    }
+
+    // >= Vista / Server 2008
+    // https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-acquiresrwlockexclusive
+    pub fn AcquireSRWLockExclusive(SRWLock: PSRWLOCK) -> () {
+        rtabort!("unavailable")
+    }
+    pub fn AcquireSRWLockShared(SRWLock: PSRWLOCK) -> () {
+        rtabort!("unavailable")
+    }
+    pub fn ReleaseSRWLockExclusive(SRWLock: PSRWLOCK) -> () {
+        rtabort!("unavailable")
+    }
+    pub fn ReleaseSRWLockShared(SRWLock: PSRWLOCK) -> () {
+        rtabort!("unavailable")
+    }
+
+    // >= Win7 / Server 2008 R2
+    // https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-tryacquiresrwlockexclusive
+    pub fn TryAcquireSRWLockExclusive(SRWLock: PSRWLOCK) -> BOOLEAN {
+        rtabort!("unavailable")
+    }
+    pub fn TryAcquireSRWLockShared(SRWLock: PSRWLOCK) -> BOOLEAN {
+        rtabort!("unavailable")
+    }
+
+    // >= Vista / Server 2008
+    // https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-sleepconditionvariablesrw
+    pub fn SleepConditionVariableSRW(
+        ConditionVariable: PCONDITION_VARIABLE,
+        SRWLock: PSRWLOCK,
+        dwMilliseconds: DWORD,
+        Flags: ULONG
+    ) -> BOOL {
+        rtabort!("unavailable")
+    }
+
+    // >= Vista / Server 2008
+    // https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-wakeconditionvariable
+    pub fn WakeConditionVariable(ConditionVariable: PCONDITION_VARIABLE) -> () {
+        rtabort!("unavailable")
+    }
+    pub fn WakeAllConditionVariable(ConditionVariable: PCONDITION_VARIABLE) -> () {
+        rtabort!("unavailable")
+    }
 }
 
 compat_fn_optional! {
@@ -396,4 +446,21 @@ compat_fn_with_fallback! {
 #[link(name = "kernel32")]
 extern "system" {
     pub fn LoadLibraryA(lpFileName: LPCSTR) -> HMODULE;
+
+    pub fn CreateMutexA(
+        lpMutexAttributes: LPSECURITY_ATTRIBUTES,
+        bInitialOwner: BOOL,
+        lpName: LPCSTR,
+    ) -> HANDLE;
+
+    pub fn ReleaseMutex(hMutex: HANDLE) -> BOOL;
+
+    pub fn CreateEventA(
+        lpEventAttributes: LPSECURITY_ATTRIBUTES,
+        bManualReset: BOOL,
+        bInitialState: BOOL,
+        lpName: LPCSTR,
+    ) -> HANDLE;
+
+    pub fn PulseEvent(hEvent: HANDLE) -> BOOL;
 }

library/std/src/sys/windows/c/windows_sys.lst

@@ -2490,8 +2490,6 @@ Windows.Win32.System.SystemServices.EXCEPTION_MAXIMUM_PARAMETERS
 Windows.Win32.System.SystemServices.IO_REPARSE_TAG_MOUNT_POINT
 Windows.Win32.System.SystemServices.IO_REPARSE_TAG_SYMLINK
 Windows.Win32.System.Threading.ABOVE_NORMAL_PRIORITY_CLASS
-Windows.Win32.System.Threading.AcquireSRWLockExclusive
-Windows.Win32.System.Threading.AcquireSRWLockShared
 Windows.Win32.System.Threading.BELOW_NORMAL_PRIORITY_CLASS
 Windows.Win32.System.Threading.CREATE_BREAKAWAY_FROM_JOB
 Windows.Win32.System.Threading.CREATE_DEFAULT_ERROR_MODE
@@ -2531,21 +2529,20 @@ Windows.Win32.System.Threading.InitOnceComplete
 Windows.Win32.System.Threading.LPTHREAD_START_ROUTINE
 Windows.Win32.System.Threading.NORMAL_PRIORITY_CLASS
 Windows.Win32.System.Threading.OpenProcessToken
+Windows.Win32.System.Threading.PCONDITION_VARIABLE
 Windows.Win32.System.Threading.PROCESS_CREATION_FLAGS
 Windows.Win32.System.Threading.PROCESS_INFORMATION
 Windows.Win32.System.Threading.PROCESS_MODE_BACKGROUND_BEGIN
 Windows.Win32.System.Threading.PROCESS_MODE_BACKGROUND_END
 Windows.Win32.System.Threading.PROFILE_KERNEL
 Windows.Win32.System.Threading.PROFILE_SERVER
 Windows.Win32.System.Threading.PROFILE_USER
+Windows.Win32.System.Threading.PSRWLOCK
 Windows.Win32.System.Threading.REALTIME_PRIORITY_CLASS
-Windows.Win32.System.Threading.ReleaseSRWLockExclusive
-Windows.Win32.System.Threading.ReleaseSRWLockShared
 Windows.Win32.System.Threading.RTL_CONDITION_VARIABLE
 Windows.Win32.System.Threading.RTL_RUN_ONCE
 Windows.Win32.System.Threading.RTL_SRWLOCK
 Windows.Win32.System.Threading.Sleep
-Windows.Win32.System.Threading.SleepConditionVariableSRW
 Windows.Win32.System.Threading.SleepEx
 Windows.Win32.System.Threading.STACK_SIZE_PARAM_IS_A_RESERVATION
 Windows.Win32.System.Threading.STARTF_FORCEOFFFEEDBACK
@@ -2574,12 +2571,8 @@ Windows.Win32.System.Threading.TlsAlloc
 Windows.Win32.System.Threading.TlsFree
 Windows.Win32.System.Threading.TlsGetValue
 Windows.Win32.System.Threading.TlsSetValue
-Windows.Win32.System.Threading.TryAcquireSRWLockExclusive
-Windows.Win32.System.Threading.TryAcquireSRWLockShared
 Windows.Win32.System.Threading.WaitForMultipleObjects
 Windows.Win32.System.Threading.WaitForSingleObject
-Windows.Win32.System.Threading.WakeAllConditionVariable
-Windows.Win32.System.Threading.WakeConditionVariable
 Windows.Win32.System.WindowsProgramming.IO_STATUS_BLOCK
 Windows.Win32.System.WindowsProgramming.OBJECT_ATTRIBUTES
 Windows.Win32.System.WindowsProgramming.PROGRESS_CONTINUE

library/std/src/sys/windows/c/windows_sys.rs

@@ -31,14 +31,6 @@ extern "system" {
     ) -> NTSTATUS;
 }
 #[link(name = "kernel32")]
-extern "system" {
-    pub fn AcquireSRWLockExclusive(srwlock: *mut RTL_SRWLOCK) -> ();
-}
-#[link(name = "kernel32")]
-extern "system" {
-    pub fn AcquireSRWLockShared(srwlock: *mut RTL_SRWLOCK) -> ();
-}
-#[link(name = "kernel32")]
 extern "system" {
     pub fn CancelIo(hfile: HANDLE) -> BOOL;
 }
@@ -428,14 +420,6 @@ extern "system" {
     ) -> BOOL;
 }
 #[link(name = "kernel32")]
-extern "system" {
-    pub fn ReleaseSRWLockExclusive(srwlock: *mut RTL_SRWLOCK) -> ();
-}
-#[link(name = "kernel32")]
-extern "system" {
-    pub fn ReleaseSRWLockShared(srwlock: *mut RTL_SRWLOCK) -> ();
-}
-#[link(name = "kernel32")]
 extern "system" {
     pub fn RemoveDirectoryW(lppathname: PCWSTR) -> BOOL;
 }
@@ -494,15 +478,6 @@ extern "system" {
     pub fn Sleep(dwmilliseconds: u32) -> ();
 }
 #[link(name = "kernel32")]
-extern "system" {
-    pub fn SleepConditionVariableSRW(
-        conditionvariable: *mut RTL_CONDITION_VARIABLE,
-        srwlock: *mut RTL_SRWLOCK,
-        dwmilliseconds: u32,
-        flags: u32,
-    ) -> BOOL;
-}
-#[link(name = "kernel32")]
 extern "system" {
     pub fn SleepEx(dwmilliseconds: u32, balertable: BOOL) -> u32;
 }
@@ -531,14 +506,6 @@ extern "system" {
     pub fn TlsSetValue(dwtlsindex: u32, lptlsvalue: *const ::core::ffi::c_void) -> BOOL;
 }
 #[link(name = "kernel32")]
-extern "system" {
-    pub fn TryAcquireSRWLockExclusive(srwlock: *mut RTL_SRWLOCK) -> BOOLEAN;
-}
-#[link(name = "kernel32")]
-extern "system" {
-    pub fn TryAcquireSRWLockShared(srwlock: *mut RTL_SRWLOCK) -> BOOLEAN;
-}
-#[link(name = "kernel32")]
 extern "system" {
     pub fn WaitForMultipleObjects(
         ncount: u32,
@@ -552,14 +519,6 @@ extern "system" {
     pub fn WaitForSingleObject(hhandle: HANDLE, dwmilliseconds: u32) -> WIN32_ERROR;
 }
 #[link(name = "kernel32")]
-extern "system" {
-    pub fn WakeAllConditionVariable(conditionvariable: *mut RTL_CONDITION_VARIABLE) -> ();
-}
-#[link(name = "kernel32")]
-extern "system" {
-    pub fn WakeConditionVariable(conditionvariable: *mut RTL_CONDITION_VARIABLE) -> ();
-}
-#[link(name = "kernel32")]
 extern "system" {
     pub fn WideCharToMultiByte(
         codepage: u32,
@@ -3736,6 +3695,7 @@ pub const PROFILE_KERNEL: PROCESS_CREATION_FLAGS = 536870912u32;
 pub const PROFILE_SERVER: PROCESS_CREATION_FLAGS = 1073741824u32;
 pub const PROFILE_USER: PROCESS_CREATION_FLAGS = 268435456u32;
 pub const PROGRESS_CONTINUE: u32 = 0u32;
+pub type PSRWLOCK = *mut RTL_SRWLOCK;
 pub type PSTR = *mut u8;
 pub type PVECTORED_EXCEPTION_HANDLER = ::core::option::Option<
     unsafe extern "system" fn(exceptioninfo: *mut EXCEPTION_POINTERS) -> i32,