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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/*
*********************************************************************
*
* Pollable events
*
* Pollable events are implemented using layered I/O. The only
* I/O methods that are implemented for pollable events are poll
* and close. No other methods can be invoked on a pollable
* event.
*
* A pipe or socket pair is created and the pollable event layer
* is pushed onto the read end. A pointer to the write end is
* saved in the PRFilePrivate structure of the pollable event.
*
*********************************************************************
*/
#include "prinit.h"
#include "prio.h"
#include "prmem.h"
#include "prerror.h"
#include "prlog.h"
/*
* These internal functions are declared in primpl.h,
* but we can't include primpl.h because the definition
* of struct PRFilePrivate in this file (for the pollable
* event layer) will conflict with the definition of
* struct PRFilePrivate in primpl.h (for the NSPR layer).
*/
extern PRIntn _PR_InvalidInt(void);
extern PRInt64 _PR_InvalidInt64(void);
extern PRStatus _PR_InvalidStatus(void);
extern PRFileDesc *_PR_InvalidDesc(void);
/*
* PRFilePrivate structure for the NSPR pollable events layer
*/
struct PRFilePrivate {
PRFileDesc *writeEnd; /* the write end of the pipe/socketpair */
};
static PRStatus PR_CALLBACK _pr_PolEvtClose(PRFileDesc *fd);
static PRInt16 PR_CALLBACK _pr_PolEvtPoll(
PRFileDesc *fd, PRInt16 in_flags, PRInt16 *out_flags);
static PRIOMethods _pr_polevt_methods = {
PR_DESC_LAYERED,
_pr_PolEvtClose,
(PRReadFN)_PR_InvalidInt,
(PRWriteFN)_PR_InvalidInt,
(PRAvailableFN)_PR_InvalidInt,
(PRAvailable64FN)_PR_InvalidInt64,
(PRFsyncFN)_PR_InvalidStatus,
(PRSeekFN)_PR_InvalidInt,
(PRSeek64FN)_PR_InvalidInt64,
(PRFileInfoFN)_PR_InvalidStatus,
(PRFileInfo64FN)_PR_InvalidStatus,
(PRWritevFN)_PR_InvalidInt,
(PRConnectFN)_PR_InvalidStatus,
(PRAcceptFN)_PR_InvalidDesc,
(PRBindFN)_PR_InvalidStatus,
(PRListenFN)_PR_InvalidStatus,
(PRShutdownFN)_PR_InvalidStatus,
(PRRecvFN)_PR_InvalidInt,
(PRSendFN)_PR_InvalidInt,
(PRRecvfromFN)_PR_InvalidInt,
(PRSendtoFN)_PR_InvalidInt,
_pr_PolEvtPoll,
(PRAcceptreadFN)_PR_InvalidInt,
(PRTransmitfileFN)_PR_InvalidInt,
(PRGetsocknameFN)_PR_InvalidStatus,
(PRGetpeernameFN)_PR_InvalidStatus,
(PRReservedFN)_PR_InvalidInt,
(PRReservedFN)_PR_InvalidInt,
(PRGetsocketoptionFN)_PR_InvalidStatus,
(PRSetsocketoptionFN)_PR_InvalidStatus,
(PRSendfileFN)_PR_InvalidInt,
(PRConnectcontinueFN)_PR_InvalidStatus,
(PRReservedFN)_PR_InvalidInt,
(PRReservedFN)_PR_InvalidInt,
(PRReservedFN)_PR_InvalidInt,
(PRReservedFN)_PR_InvalidInt
};
static PRDescIdentity _pr_polevt_id;
static PRCallOnceType _pr_polevt_once_control;
static PRStatus PR_CALLBACK _pr_PolEvtInit(void);
static PRInt16 PR_CALLBACK _pr_PolEvtPoll(
PRFileDesc *fd, PRInt16 in_flags, PRInt16 *out_flags)
{
return (fd->lower->methods->poll)(fd->lower, in_flags, out_flags);
}
static PRStatus PR_CALLBACK _pr_PolEvtInit(void)
{
_pr_polevt_id = PR_GetUniqueIdentity("NSPR pollable events");
if (PR_INVALID_IO_LAYER == _pr_polevt_id) {
return PR_FAILURE;
}
return PR_SUCCESS;
}
#if !defined(XP_UNIX)
#define USE_TCP_SOCKETPAIR
#endif
PR_IMPLEMENT(PRFileDesc *) PR_NewPollableEvent(void)
{
PRFileDesc *event;
PRFileDesc *fd[2]; /* fd[0] is the read end; fd[1] is the write end */
#ifdef USE_TCP_SOCKETPAIR
PRSocketOptionData socket_opt;
PRStatus rv;
#endif
fd[0] = fd[1] = NULL;
if (PR_CallOnce(&_pr_polevt_once_control, _pr_PolEvtInit) == PR_FAILURE) {
return NULL;
}
event = PR_CreateIOLayerStub(_pr_polevt_id, &_pr_polevt_methods);
if (NULL == event) {
goto errorExit;
}
event->secret = PR_NEW(PRFilePrivate);
if (event->secret == NULL) {
PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
goto errorExit;
}
#ifndef USE_TCP_SOCKETPAIR
if (PR_CreatePipe(&fd[0], &fd[1]) == PR_FAILURE) {
fd[0] = fd[1] = NULL;
goto errorExit;
}
#else
if (PR_NewTCPSocketPair(fd) == PR_FAILURE) {
fd[0] = fd[1] = NULL;
goto errorExit;
}
/*
* set the TCP_NODELAY option to reduce notification latency
*/
socket_opt.option = PR_SockOpt_NoDelay;
socket_opt.value.no_delay = PR_TRUE;
rv = PR_SetSocketOption(fd[1], &socket_opt);
PR_ASSERT(PR_SUCCESS == rv);
#endif
event->secret->writeEnd = fd[1];
if (PR_PushIOLayer(fd[0], PR_TOP_IO_LAYER, event) == PR_FAILURE) {
goto errorExit;
}
return fd[0];
errorExit:
if (fd[0]) {
PR_Close(fd[0]);
PR_Close(fd[1]);
}
if (event) {
PR_DELETE(event->secret);
event->dtor(event);
}
return NULL;
}
static PRStatus PR_CALLBACK _pr_PolEvtClose(PRFileDesc *fd)
{
PRFileDesc *event;
event = PR_PopIOLayer(fd, PR_TOP_IO_LAYER);
PR_ASSERT(NULL == event->higher && NULL == event->lower);
PR_Close(fd);
PR_Close(event->secret->writeEnd);
PR_DELETE(event->secret);
event->dtor(event);
return PR_SUCCESS;
}
PR_IMPLEMENT(PRStatus) PR_DestroyPollableEvent(PRFileDesc *event)
{
return PR_Close(event);
}
static const char magicChar = '\x38';
PR_IMPLEMENT(PRStatus) PR_SetPollableEvent(PRFileDesc *event)
{
if (PR_Write(event->secret->writeEnd, &magicChar, 1) != 1) {
return PR_FAILURE;
}
return PR_SUCCESS;
}
PR_IMPLEMENT(PRStatus) PR_WaitForPollableEvent(PRFileDesc *event)
{
char buf[1024];
PRInt32 nBytes;
#ifdef DEBUG
PRIntn i;
#endif
nBytes = PR_Read(event->lower, buf, sizeof(buf));
if (nBytes == -1) {
return PR_FAILURE;
}
#ifdef DEBUG
/*
* Make sure people do not write to the pollable event fd
* directly.
*/
for (i = 0; i < nBytes; i++) {
PR_ASSERT(buf[i] == magicChar);
}
#endif
return PR_SUCCESS;
}