You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
191 lines
3.8 KiB
191 lines
3.8 KiB
/*++
|
|
|
|
Copyright (c) 1996 Microsoft Corporation
|
|
|
|
Module Name:
|
|
|
|
reslock.hxx
|
|
|
|
Abstract:
|
|
|
|
Contains RESOURCE_LOCK class
|
|
|
|
Author:
|
|
|
|
Richard L Firth (rfirth) 18-Jun-1996
|
|
|
|
Revision History:
|
|
|
|
18-Jun-1996 rfirth
|
|
Created
|
|
|
|
--*/
|
|
|
|
//
|
|
// manifests
|
|
//
|
|
|
|
#if INET_DEBUG
|
|
|
|
#define DEFAULT_RESOURCE_LOCK_TIMEOUT 30000 // 30 seconds
|
|
|
|
#else
|
|
|
|
#define DEFAULT_RESOURCE_LOCK_TIMEOUT INFINITE
|
|
|
|
#endif
|
|
|
|
//
|
|
// class definition
|
|
//
|
|
|
|
class RESOURCE_LOCK {
|
|
|
|
private:
|
|
|
|
//
|
|
// _Initialized - TRUE when the critical section & event have been created
|
|
//
|
|
|
|
BOOL _Initialized;
|
|
|
|
//
|
|
// _WriteCount - number of times writer has re-entered
|
|
//
|
|
|
|
LONG _WriteCount;
|
|
|
|
//
|
|
// _ThreadId - ID of the owning writer thread
|
|
//
|
|
|
|
DWORD _ThreadId;
|
|
|
|
//
|
|
// _Readers - number of reader threads. Used as a switch in concert with
|
|
// InterlockedIncrement/InterlockedDecrement: -1 => 0 means this is the
|
|
// first reader, and we reset the writer wait event; 0 => -1 means this is
|
|
// the last reader and we set the writer wait event
|
|
//
|
|
|
|
LONG _Readers;
|
|
|
|
//
|
|
// _Timeout - number of milliseconds to wait for one of the event handles
|
|
//
|
|
|
|
DWORD _Timeout;
|
|
|
|
//
|
|
// _hWriteEvent - signalled when the last reader thread exits. At this time
|
|
// the writer thread has exclusive access
|
|
//
|
|
|
|
HANDLE _hWriteEvent;
|
|
|
|
//
|
|
// _CritSect - used to serialize access. Writer keeps this until Releas()ed.
|
|
// Readers just keep it long enough to update _Readers variable
|
|
//
|
|
|
|
CCritSec _CritSect;
|
|
|
|
//
|
|
// Wait - wait for an event to become signalled
|
|
//
|
|
|
|
BOOL Wait(HANDLE hEvent) {
|
|
|
|
DWORD error = WaitForSingleObject(hEvent, _Timeout);
|
|
|
|
if (error == WAIT_OBJECT_0) {
|
|
return TRUE;
|
|
} else {
|
|
|
|
DEBUG_PRINT(UTIL,
|
|
ERROR,
|
|
("RESOURCE_LOCK::Wait(): WaitForSingleObject() returns %d\n",
|
|
error
|
|
));
|
|
|
|
if (error == WAIT_TIMEOUT) {
|
|
error = ERROR_WINHTTP_TIMEOUT;
|
|
} else {
|
|
error = ERROR_WINHTTP_INTERNAL_ERROR;
|
|
}
|
|
SetLastError(error);
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
VOID SetTimeout(DWORD Timeout) {
|
|
_Timeout = Timeout;
|
|
}
|
|
|
|
DWORD GetTimeout(VOID) const {
|
|
return _Timeout;
|
|
}
|
|
|
|
public:
|
|
|
|
RESOURCE_LOCK() {
|
|
_WriteCount = 0;
|
|
_ThreadId = 0;
|
|
_Readers = -1;
|
|
_Timeout = DEFAULT_RESOURCE_LOCK_TIMEOUT;
|
|
_hWriteEvent = NULL;
|
|
_Initialized = FALSE;
|
|
}
|
|
|
|
~RESOURCE_LOCK() {
|
|
|
|
INET_ASSERT(_WriteCount == 0);
|
|
INET_ASSERT(_ThreadId == 0);
|
|
INET_ASSERT(_Readers == -1);
|
|
|
|
if (_hWriteEvent != NULL) {
|
|
CloseHandle(_hWriteEvent);
|
|
}
|
|
}
|
|
|
|
VOID Initialize(VOID) {
|
|
_WriteCount = 0;
|
|
_ThreadId = 0;
|
|
_Readers = -1;
|
|
_Timeout = DEFAULT_RESOURCE_LOCK_TIMEOUT;
|
|
_CritSect.Init();
|
|
|
|
//
|
|
// _hWriteEvent is an auto-reset, initially-signalled event
|
|
//
|
|
|
|
_hWriteEvent = CreateEvent(NULL, FALSE, TRUE, NULL);
|
|
|
|
if (_CritSect.IsInitialized() && _hWriteEvent != NULL)
|
|
_Initialized = TRUE;
|
|
else
|
|
_Initialized = FALSE;
|
|
}
|
|
|
|
BOOL IsInitialized(VOID) const {
|
|
return _Initialized;
|
|
}
|
|
|
|
BOOL IsValid(VOID) const {
|
|
return (_hWriteEvent != NULL) ? TRUE : FALSE;
|
|
}
|
|
|
|
BOOL
|
|
Acquire(
|
|
IN BOOL bExclusiveMode = FALSE
|
|
);
|
|
|
|
BOOL AcquireExclusive(VOID) {
|
|
return Acquire(TRUE);
|
|
}
|
|
|
|
VOID
|
|
Release(
|
|
VOID
|
|
);
|
|
};
|