tclwinthrd.c

这是leon3处理器的交叉编译链

/* 
 * tclWinThread.c --
 *
 *	This file implements the Windows-specific thread operations.
 *
 * Copyright (c) 1998 by Sun Microsystems, Inc.
 * Copyright (c) 1999 by Scriptics Corporation
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclWinThrd.c,v 1.20 2002/08/29 19:02:19 andreas_kupries Exp $
 */

#include "tclWinInt.h"

#include <fcntl.h>
#include <io.h>
#include <sys/stat.h>

/*
 * This is the master lock used to serialize access to other
 * serialization data structures.
 */

static CRITICAL_SECTION masterLock;
static int init = 0;
#define MASTER_LOCK  EnterCriticalSection(&masterLock)
#define MASTER_UNLOCK  LeaveCriticalSection(&masterLock)

/*
 * This is the master lock used to serialize initialization and finalization
 * of Tcl as a whole.
 */

static CRITICAL_SECTION initLock;

/*
 * allocLock is used by Tcl's version of malloc for synchronization.
 * For obvious reasons, cannot use any dyamically allocated storage.
 */

static CRITICAL_SECTION allocLock;
static Tcl_Mutex allocLockPtr = (Tcl_Mutex) &allocLock;

/*
 * The joinLock serializes Create- and ExitThread. This is necessary to
 * prevent a race where a new joinable thread exits before the creating
 * thread had the time to create the necessary data structures in the
 * emulation layer.
 */

static CRITICAL_SECTION joinLock;

/*
 * Condition variables are implemented with a combination of a 
 * per-thread Windows Event and a per-condition waiting queue.
 * The idea is that each thread has its own Event that it waits
 * on when it is doing a ConditionWait; it uses the same event for
 * all condition variables because it only waits on one at a time.
 * Each condition variable has a queue of waiting threads, and a 
 * mutex used to serialize access to this queue.
 *
 * Special thanks to David Nichols and
 * Jim Davidson for advice on the Condition Variable implementation.
 */

/*
 * The per-thread event and queue pointers.
 */

typedef struct ThreadSpecificData {
    HANDLE condEvent;			/* Per-thread condition event */
    struct ThreadSpecificData *nextPtr;	/* Queue pointers */
    struct ThreadSpecificData *prevPtr;
    int flags;				/* See flags below */
} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;

/*
 * State bits for the thread.
 * WIN_THREAD_UNINIT		Uninitialized.  Must be zero because
 *				of the way ThreadSpecificData is created.
 * WIN_THREAD_RUNNING		Running, not waiting.
 * WIN_THREAD_BLOCKED		Waiting, or trying to wait.
 * WIN_THREAD_DEAD		Dying - no per-thread event anymore.
 */ 

#define WIN_THREAD_UNINIT	0x0
#define WIN_THREAD_RUNNING	0x1
#define WIN_THREAD_BLOCKED	0x2
#define WIN_THREAD_DEAD		0x4

/*
 * The per condition queue pointers and the
 * Mutex used to serialize access to the queue.
 */

typedef struct WinCondition {
    CRITICAL_SECTION condLock;	/* Lock to serialize queuing on the condition */
    struct ThreadSpecificData *firstPtr;	/* Queue pointers */
    struct ThreadSpecificData *lastPtr;
} WinCondition;


/*
 *----------------------------------------------------------------------
 *
 * Tcl_CreateThread --
 *
 *	This procedure creates a new thread.
 *
 * Results:
 *	TCL_OK if the thread could be created.  The thread ID is
 *	returned in a parameter.
 *
 * Side effects:
 *	A new thread is created.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_CreateThread(idPtr, proc, clientData, stackSize, flags)
    Tcl_ThreadId *idPtr;		/* Return, the ID of the thread */
    Tcl_ThreadCreateProc proc;		/* Main() function of the thread */
    ClientData clientData;		/* The one argument to Main() */
    int stackSize;			/* Size of stack for the new thread */
    int flags;				/* Flags controlling behaviour of
					 * the new thread */
{
    HANDLE tHandle;

    EnterCriticalSection(&joinLock);

#if defined(__MSVCRT__) || defined(__BORLANDC__)
    tHandle = (HANDLE) _beginthreadex(NULL, (unsigned) stackSize, proc,
	clientData, 0, (unsigned *)idPtr);
#else
    tHandle = CreateThread(NULL, (DWORD) stackSize,
	    (LPTHREAD_START_ROUTINE) proc, (LPVOID) clientData,
	    (DWORD) 0, (LPDWORD)idPtr);
#endif

    if (tHandle == NULL) {
        LeaveCriticalSection(&joinLock);
	return TCL_ERROR;
    } else {
        if (flags & TCL_THREAD_JOINABLE) {
	    TclRememberJoinableThread (*idPtr);
	}

	/*
	 * The only purpose of this is to decrement the reference count so the
	 * OS resources will be reaquired when the thread closes.
	 */

	CloseHandle(tHandle);
	LeaveCriticalSection(&joinLock);
	return TCL_OK;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_JoinThread --
 *
 *	This procedure waits upon the exit of the specified thread.
 *
 * Results:
 *	TCL_OK if the wait was successful, TCL_ERROR else.
 *
 * Side effects:
 *	The result area is set to the exit code of the thread we
 *	waited upon.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_JoinThread(id, result)
    Tcl_ThreadId id;	/* Id of the thread to wait upon */
    int*     result;	/* Reference to the storage the result
			 * of the thread we wait upon will be
			 * written into. */
{
    return TclJoinThread (id, result);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpThreadExit --
 *
 *	This procedure terminates the current thread.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	This procedure terminates the current thread.
 *
 *----------------------------------------------------------------------
 */

void
TclpThreadExit(status)
    int status;
{
    EnterCriticalSection(&joinLock);
    TclSignalExitThread (Tcl_GetCurrentThread (), status);
    LeaveCriticalSection(&joinLock);

#if defined(__MSVCRT__) || defined(__BORLANDC__)
    _endthreadex((unsigned) status);
#else
    ExitThread((DWORD) status);
#endif
}


/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetCurrentThread --
 *
 *	This procedure returns the ID of the currently running thread.
 *
 * Results:
 *	A thread ID.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

Tcl_ThreadId
Tcl_GetCurrentThread()
{
    return (Tcl_ThreadId)GetCurrentThreadId();
}


/*
 *----------------------------------------------------------------------
 *
 * TclpInitLock
 *
 *	This procedure is used to grab a lock that serializes initialization
 *	and finalization of Tcl.  On some platforms this may also initialize
 *	the mutex used to serialize creation of more mutexes and thread
 *	local storage keys.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Acquire the initialization mutex.
 *
 *----------------------------------------------------------------------
 */

void
TclpInitLock()
{
    if (!init) {
	/*
	 * There is a fundamental race here that is solved by creating
	 * the first Tcl interpreter in a single threaded environment.
	 * Once the interpreter has been created, it is safe to create
	 * more threads that create interpreters in parallel.
	 */
	init = 1;
	InitializeCriticalSection(&joinLock);
	InitializeCriticalSection(&initLock);
	InitializeCriticalSection(&masterLock);
    }
    EnterCriticalSection(&initLock);
}


/*
 *----------------------------------------------------------------------
 *
 * TclpInitUnlock
 *
 *	This procedure is used to release a lock that serializes initialization
 *	and finalization of Tcl.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Release the initialization mutex.
 *
 *----------------------------------------------------------------------
 */

void
TclpInitUnlock()
{
    LeaveCriticalSection(&initLock);
}


/*
 *----------------------------------------------------------------------
 *
 * TclpMasterLock
 *
 *	This procedure is used to grab a lock that serializes creation
 *	of mutexes, condition variables, and thread local storage keys.
 *
 *	This lock must be different than the initLock because the
 *	initLock is held during creation of syncronization objects.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Acquire the master mutex.
 *
 *----------------------------------------------------------------------
 */

void
TclpMasterLock()
{
    if (!init) {
	/*
	 * There is a fundamental race here that is solved by creating
	 * the first Tcl interpreter in a single threaded environment.
	 * Once the interpreter has been created, it is safe to create
	 * more threads that create interpreters in parallel.
	 */
	init = 1;
	InitializeCriticalSection(&joinLock);
	InitializeCriticalSection(&initLock);
	InitializeCriticalSection(&masterLock);
    }
    EnterCriticalSection(&masterLock);
}


/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetAllocMutex
 *
 *	This procedure returns a pointer to a statically initialized
 *	mutex for use by the memory allocator.  The alloctor must
 *	use this lock, because all other locks are allocated...
 *
 * Results:
 *	A pointer to a mutex that is suitable for passing to
 *	Tcl_MutexLock and Tcl_MutexUnlock.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

Tcl_Mutex *
Tcl_GetAllocMutex()
{
#ifdef TCL_THREADS
    static int once = 0;

    if (!once) {
	InitializeCriticalSection(&allocLock);
	once = 1;
    }
    return &allocLockPtr;
#else
    return NULL;
#endif
}


#ifdef TCL_THREADS

/* locally used prototype */
static void FinalizeConditionEvent(ClientData data);

/*
 *----------------------------------------------------------------------
 *
 * TclpMasterUnlock
 *
 *	This procedure is used to release a lock that serializes creation
 *	and deletion of synchronization objects.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Release the master mutex.
 *
 *----------------------------------------------------------------------
 */

void
TclpMasterUnlock()
{
    LeaveCriticalSection(&masterLock);
}


/*
 *----------------------------------------------------------------------
 *
 * Tcl_MutexLock --
 *
 *	This procedure is invoked to lock a mutex.  This is a self 
 *	initializing mutex that is automatically finalized during
 *	Tcl_Finalize.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	May block the current thread.  The mutex is aquired when
 *	this returns.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_MutexLock(mutexPtr)
    Tcl_Mutex *mutexPtr;	/* The lock */
{
    CRITICAL_SECTION *csPtr;
    if (*mutexPtr == NULL) {
	MASTER_LOCK;

	/* 
	 * Double inside master lock check to avoid a race.
	 */

	if (*mutexPtr == NULL) {
	    csPtr = (CRITICAL_SECTION *)ckalloc(sizeof(CRITICAL_SECTION));
	    InitializeCriticalSection(csPtr);
	    *mutexPtr = (Tcl_Mutex)csPtr;
	    TclRememberMutex(mutexPtr);
	}
	MASTER_UNLOCK;
    }
    csPtr = *((CRITICAL_SECTION **)mutexPtr);
    EnterCriticalSection(csPtr);
}


/*
 *----------------------------------------------------------------------
 *
 * Tcl_MutexUnlock --
 *
 *	This procedure is invoked to unlock a mutex.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The mutex is released when this returns.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_MutexUnlock(mutexPtr)
    Tcl_Mutex *mutexPtr;	/* The lock */
{
    CRITICAL_SECTION *csPtr = *((CRITICAL_SECTION **)mutexPtr);
    LeaveCriticalSection(csPtr);
}


/*
 *----------------------------------------------------------------------
 *
 * TclpFinalizeMutex --
 *
 *	This procedure is invoked to clean up one mutex.  This is only
 *	safe to call at the end of time.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The mutex list is deallocated.
 *
 *----------------------------------------------------------------------
 */

void
TclpFinalizeMutex(mutexPtr)
    Tcl_Mutex *mutexPtr;
{
    CRITICAL_SECTION *csPtr = *(CRITICAL_SECTION **)mutexPtr;
    if (csPtr != NULL) {
	DeleteCriticalSection(csPtr);
	ckfree((char *)csPtr);
	*mutexPtr = NULL;
    }
}


/*
 *----------------------------------------------------------------------
 *
 * TclpThreadDataKeyInit --
 *
 *	This procedure initializes a thread specific data block key.
 *	Each thread has table of pointers to thread specific data.
 *	all threads agree on which table entry is used by each module.
 *	this is remembered in a "data key", that is just an index into
 *	this table.  To allow self initialization, the interface
 *	passes a pointer to this key and the first thread to use
 *	the key fills in the pointer to the key.  The key should be
 *	a process-wide static.