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/*
* BRLTTY - A background process providing access to the console screen (when in
* text mode) for a blind person using a refreshable braille display.
*
* Copyright (C) 1995-2024 by The BRLTTY Developers.
*
* BRLTTY comes with ABSOLUTELY NO WARRANTY.
*
* This is free software, placed under the terms of the
* GNU Lesser General Public License, as published by the Free Software
* Foundation; either version 2.1 of the License, or (at your option) any
* later version. Please see the file LICENSE-LGPL for details.
*
* Web Page: http://brltty.app/
*
* This software is maintained by Dave Mielke <dave@mielke.cc>.
*/
#include "prologue.h"
#include <string.h>
#include "log.h"
#include "async_wait.h"
#include "async_internal.h"
#include "timing.h"
typedef struct {
AsyncThreadSpecificData *tsd;
long int timeout;
} CallbackExecuterParameters;
typedef int CallbackExecuter (CallbackExecuterParameters *parameters);
typedef struct {
CallbackExecuter *execute;
const char *action;
} CallbackExecuterEntry;
struct AsyncWaitDataStruct {
AsyncThreadSpecificData *tsd;
unsigned int waitDepth;
};
static int
alarmCallbackExecuter (CallbackExecuterParameters *parameters) {
return asyncExecuteAlarmCallback(parameters->tsd->alarmData, ¶meters->timeout);
}
static int
taskCallbackExecuter (CallbackExecuterParameters *parameters) {
AsyncThreadSpecificData *tsd = parameters->tsd;
if (tsd->waitData->waitDepth != 1) return 0;
return asyncExecuteTaskCallback(tsd->taskData);
}
static int
ioCallbackExecuter (CallbackExecuterParameters *parameters) {
return asyncExecuteIoCallback(parameters->tsd->ioData, parameters->timeout);
}
static const CallbackExecuterEntry callbackExecuterTable[] = {
{ .execute = alarmCallbackExecuter,
.action = "alarm handled"
},
{ .execute = taskCallbackExecuter,
.action = "task performed"
},
{ .execute = ioCallbackExecuter,
.action = "I/O operation handled"
},
{ .execute = NULL,
.action = "wait timed out"
}
};
void
asyncDeallocateWaitData (AsyncWaitData *wd) {
if (wd) {
free(wd);
}
}
static AsyncWaitData *
getWaitData (void) {
AsyncThreadSpecificData *tsd = asyncGetThreadSpecificData();
if (!tsd) return NULL;
if (!tsd->waitData) {
AsyncWaitData *wd;
if (!(wd = malloc(sizeof(*wd)))) {
logMallocError();
return NULL;
}
memset(wd, 0, sizeof(*wd));
wd->tsd = tsd;
wd->waitDepth = 0;
tsd->waitData = wd;
}
return tsd->waitData;
}
static void
awaitAction (long int timeout) {
AsyncWaitData *wd = getWaitData();
if (wd) {
const CallbackExecuterEntry *cbx = callbackExecuterTable;
CallbackExecuterParameters parameters = {
.tsd = wd->tsd,
.timeout = timeout
};
wd->waitDepth += 1;
logMessage(LOG_CATEGORY(ASYNC_EVENTS),
"begin: level %u: timeout %ld",
wd->waitDepth, timeout);
while (cbx->execute) {
if (cbx->execute(¶meters)) break;
cbx += 1;
}
logMessage(LOG_CATEGORY(ASYNC_EVENTS),
"end: level %u: %s",
wd->waitDepth, cbx->action);
wd->waitDepth -= 1;
} else {
logMessage(LOG_CATEGORY(ASYNC_EVENTS), "waiting: %ld", timeout);
approximateDelay(timeout);
}
}
int
asyncAwaitCondition (int timeout, AsyncConditionTester *testCondition, void *data) {
int first = 1;
TimePeriod period;
startTimePeriod(&period, timeout);
while (!(testCondition && testCondition(data))) {
long int elapsed;
if (first) {
first = 0;
elapsed = 0;
} else if (afterTimePeriod(&period, &elapsed)) {
return 0;
}
awaitAction(timeout - elapsed);
}
logSymbol(LOG_CATEGORY(ASYNC_EVENTS), testCondition, "condition satisfied");
return 1;
}
void
asyncWait (int duration) {
asyncAwaitCondition(duration, NULL, NULL);
}
void
asyncWaitFor (AsyncConditionTester *testCondition, void *data) {
while (!asyncAwaitCondition(1000000, testCondition, data));
}
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