/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
* You may select, at your option, one of the above-listed licenses.
*/
#include "platform.h"
#include <stdio.h> /* fprintf, open, fdopen, fread, _fileno, stdin, stdout */
#include <stdlib.h> /* malloc, free */
#include <assert.h>
#include <errno.h> /* errno */
#if defined (_MSC_VER)
# include <sys/stat.h>
# include <io.h>
#endif
#include "fileio_asyncio.h"
#include "fileio_common.h"
/* **********************************************************************
* Sparse write
************************************************************************/
/** AIO_fwriteSparse() :
* @return : storedSkips,
* argument for next call to AIO_fwriteSparse() or AIO_fwriteSparseEnd() */
static unsigned
AIO_fwriteSparse(FILE* file,
const void* buffer, size_t bufferSize,
const FIO_prefs_t* const prefs,
unsigned storedSkips)
{
const size_t* const bufferT = (const size_t*)buffer; /* Buffer is supposed malloc'ed, hence aligned on size_t */
size_t bufferSizeT = bufferSize / sizeof(size_t);
const size_t* const bufferTEnd = bufferT + bufferSizeT;
const size_t* ptrT = bufferT;
static const size_t segmentSizeT = (32 KB) / sizeof(size_t); /* check every 32 KB */
if (prefs->testMode) return 0; /* do not output anything in test mode */
if (!prefs->sparseFileSupport) { /* normal write */
size_t const sizeCheck = fwrite(buffer, 1, bufferSize, file);
if (sizeCheck != bufferSize)
EXM_THROW(70, "Write error : cannot write block : %s",
strerror(errno));
return 0;
}
/* avoid int overflow */
if (storedSkips > 1 GB) {
if (LONG_SEEK(file, 1 GB, SEEK_CUR) != 0)
EXM_THROW(91, "1 GB skip error (sparse file support)");
storedSkips -= 1 GB;
}
while (ptrT < bufferTEnd) {
size_t nb0T;
/* adjust last segment if < 32 KB */
size_t seg0SizeT = segmentSizeT;
if (seg0SizeT > bufferSizeT) seg0SizeT = bufferSizeT;
bufferSizeT -= seg0SizeT;
/* count leading zeroes */
for (nb0T=0; (nb0T < seg0SizeT) && (ptrT[nb0T] == 0); nb0T++) ;
storedSkips += (unsigned)(nb0T * sizeof(size_t));
if (nb0T != seg0SizeT) { /* not all 0s */
size_t const nbNon0ST = seg0SizeT - nb0T;
/* skip leading zeros */
if (LONG_SEEK(file, storedSkips, SEEK_CUR) != 0)
EXM_THROW(92, "Sparse skip error ; try --no-sparse");
storedSkips = 0;
/* write the rest */
if (fwrite(ptrT + nb0T, sizeof(size_t), nbNon0ST, file) != nbNon0ST)
EXM_THROW(93, "Write error : cannot write block : %s",
strerror(errno));
}
ptrT += seg0SizeT;
}
{ static size_t const maskT = sizeof(size_t)-1;
if (bufferSize & maskT) {
/* size not multiple of sizeof(size_t) : implies end of block */
const char* const restStart = (const char*)bufferTEnd;
const char* restPtr = restStart;
const char* const restEnd = (const char*)buffer + bufferSize;
assert(restEnd > restStart && restEnd < restStart + sizeof(size_t));
for ( ; (restPtr < restEnd) && (*restPtr == 0); restPtr++) ;
storedSkips += (unsigned) (restPtr - restStart);
if (restPtr != restEnd) {
/* not all remaining bytes are 0 */
size_t const restSize = (size_t)(restEnd - restPtr);
if (LONG_SEEK(file, storedSkips, SEEK_CUR) != 0)
EXM_THROW(92, "Sparse skip error ; try --no-sparse");
if (fwrite(restPtr, 1, restSize, file) != restSize)
EXM_THROW(95, "Write error : cannot write end of decoded block : %s",
strerror(errno));
storedSkips = 0;
} } }
return storedSkips;
}
static void
AIO_fwriteSparseEnd(const FIO_prefs_t* const prefs, FILE* file, unsigned storedSkips)
{
if (prefs->testMode) assert(storedSkips == 0);
if (storedSkips>0) {
assert(prefs->sparseFileSupport > 0); /* storedSkips>0 implies sparse support is enabled */
(void)prefs; /* assert can be disabled, in which case prefs becomes unused */
if (LONG_SEEK(file, storedSkips-1, SEEK_CUR) != 0)
EXM_THROW(69, "Final skip error (sparse file support)");
/* last zero must be explicitly written,
* so that skipped ones get implicitly translated as zero by FS */
{ const char lastZeroByte[1] = { 0 };
if (fwrite(lastZeroByte, 1, 1, file) != 1)
EXM_THROW(69, "Write error : cannot write last zero : %s", strerror(errno));
} }
}
/* **********************************************************************
* AsyncIO functionality
************************************************************************/
/* AIO_supported:
* Returns 1 if AsyncIO is supported on the system, 0 otherwise. */
int AIO_supported(void) {
#ifdef ZSTD_MULTITHREAD
return 1;
#else
return 0;
#endif
}
/* ***********************************
* Generic IoPool implementation
*************************************/
static IOJob_t *AIO_IOPool_createIoJob(IOPoolCtx_t *ctx, size_t bufferSize) {
IOJob_t* const job = (IOJob_t*) malloc(sizeof(IOJob_t));
void* const buffer = malloc(bufferSize);
if(!job || !buffer)
EXM_THROW(101, "Allocation error : not enough memory");
job->buffer = buffer;
job->bufferSize = bufferSize;
job->usedBufferSize = 0;
job->file = NULL;
job->ctx = ctx;
job->offset = 0;
return job;
}
/* AIO_IOPool_createThreadPool:
* Creates a thread pool and a mutex for threaded IO pool.
* Displays warning if asyncio is requested but MT isn't available. */
static void AIO_IOPool_createThreadPool(IOPoolCtx_t* ctx, const FIO_prefs_t* prefs) {
ctx->threadPool = NULL;
ctx->threadPoolActive = 0;
if(prefs->asyncIO) {
if (ZSTD_pthread_mutex_init(&ctx->ioJobsMutex, NULL))
EXM_THROW(102,"Failed creating ioJobsMutex mutex");
/* We want MAX_IO_JOBS-2 queue items because we need to always have 1 free buffer to
* decompress into and 1 buffer that's actively written to disk and owned by the writing thread. */
assert(MAX_IO_JOBS >= 2);
ctx->threadPool = POOL_create(1, MAX_IO_JOBS - 2);
ctx->threadPoolActive = 1;
if (!ctx->threadPool)
EXM_THROW(104, "Failed creating I/O thread pool");
}
}
/* AIO_IOPool_init:
* Allocates and sets and a new I/O thread pool including its included availableJobs. */
static void AIO_IOPool_init(IOPoolCtx_t* ctx, const FIO_prefs_t* prefs, POOL_function poolFunction, size_t bufferSize) {
int i;
AIO_IOPool_createThreadPool(ctx, prefs);
ctx->prefs = prefs;
ctx->poolFunction = poolFunction;
ctx->totalIoJobs = ctx->threadPool ? MAX_IO_JOBS : 2;
ctx->availableJobsCount = ctx->totalIoJobs;
for(i=0; i < ctx->availableJobsCount; i++) {
ctx->availableJobs[i] = AIO_IOPool_createIoJob(ctx, bufferSize);
}
ctx->jobBufferSize = bufferSize;
ctx->file = NULL;
}
/* AIO_IOPool_threadPoolActive:
* Check if current operation uses thread pool.
* Note that in some cases we have a thread pool initialized but choose not to use it. */
static int AIO_IOPool_threadPoolActive(IOPoolCtx_t* ctx) {
return ctx->threadPool && ctx->threadPoolActive;
}
/* AIO_IOPool_lockJobsMutex:
* Locks the IO jobs mutex if threading is active */
static void AIO_IOPool_lockJobsMutex(IOPoolCtx_t* ctx) {
if(AIO_IOPool_threadPoolActive(ctx))
ZSTD_pthread_mutex_lock(&ctx->ioJobsMutex);
}
/* AIO_IOPool_unlockJobsMutex:
* Unlocks the IO jobs mutex if threading is active */
static void AIO_IOPool_unlockJobsMutex(IOPoolCtx_t* ctx) {
if(AIO_IOPool_threadPoolActive(ctx))
ZSTD_pthread_mutex_unlock(&ctx->ioJobsMutex);
}
/* AIO_IOPool_releaseIoJob:
* Releases an acquired job back to the pool. Doesn't execute the job. */
static void AIO_IOPool_releaseIoJob(IOJob_t* job) {
IOPoolCtx_t* const ctx = (IOPoolCtx_t *) job->ctx;
AIO_IOPool_lockJobsMutex(ctx);
assert(ctx->availableJobsCount < ctx->totalIoJobs);
ctx->availableJobs[ctx->availableJobsCount++] = job;
AIO_IOPool_unlockJobsMutex(ctx);
}
/* AIO_IOPool_join:
* Waits for all tasks in the pool to finish executing. */
static void AIO_IOPool_join(IOPoolCtx_t* ctx) {
if(AIO_IOPool_threadPoolActive(ctx))
POOL_joinJobs(ctx->threadPool);
}
/* AIO_IOPool_setThreaded:
* Allows (de)activating threaded mode, to be used when the expected overhead
* of threading costs more than the expected gains. */
static void AIO_IOPool_setThreaded(IOPoolCtx_t* ctx, int threaded) {
assert(threaded == 0 || threaded == 1);
assert(ctx != NULL);
if(ctx->threadPoolActive != threaded) {
AIO_IOPool_join(ctx);
ctx->threadPoolActive = threaded;
}
}
/* AIO_IOPool_free:
* Release a previously allocated IO thread pool. Makes sure all tasks are done and released. */
static void AIO_IOPool_destroy(IOPoolCtx_t* ctx) {
int i;
if(ctx->threadPool) {
/* Make sure we finish all tasks and then free the resources */
AIO_IOPool_join(ctx);
/* Make sure we are not leaking availableJobs */
assert(ctx->availableJobsCount == ctx->totalIoJobs);
POOL_free(ctx->threadPool);
ZSTD_pthread_mutex_destroy(&ctx->ioJobsMutex);
}
assert(ctx->file == NULL);
for(i=0; i<ctx->availableJobsCount; i++) {
IOJob_t* job = (IOJob_t*) ctx->availableJobs[i];
free(job->buffer);
free(job);
}
}
/* AIO_IOPool_acquireJob:
* Returns an available io job to be used for a future io. */
static IOJob_t* AIO_IOPool_acquireJob(IOPoolCtx_t* ctx) {
IOJob_t *job;
assert(ctx->file != NULL || ctx->prefs->testMode);
AIO_IOPool_lockJobsMutex(ctx);
assert(ctx->availableJobsCount > 0);
job = (IOJob_t*) ctx->availableJobs[--ctx->availableJobsCount];
AIO_IOPool_unlockJobsMutex(ctx);
job->usedBufferSize = 0;
job->file = ctx->file;
job->offset = 0;
return job;
}
/* AIO_IOPool_setFile:
* Sets the destination file for future files in the pool.
* Requires completion of all queued jobs and release of all otherwise acquired jobs. */
static void AIO_IOPool_setFile(IOPoolCtx_t* ctx, FILE* file) {
assert(ctx!=NULL);
AIO_IOPool_join(ctx);
assert(ctx->availableJobsCount == ctx->totalIoJobs);
ctx->file = file;
}
static FILE* AIO_IOPool_getFile(const IOPoolCtx_t* ctx) {
return ctx->file;
}
/* AIO_IOPool_enqueueJob:
* Enqueues an io job for execution.
* The queued job shouldn't be used directly after queueing it. */
static void AIO_IOPool_enqueueJob(IOJob_t* job) {
IOPoolCtx_t* const ctx = (IOPoolCtx_t *)job->ctx;
if(AIO_IOPool_threadPoolActive(ctx))
POOL_add(ctx->threadPool, ctx->poolFunction, job);
else
ctx->poolFunction(job);
}
/* ***********************************
* WritePool implementation
*************************************/
/* AIO_WritePool_acquireJob:
* Returns an available write job to be used for a future write. */
IOJob_t* AIO_WritePool_acquireJob(WritePoolCtx_t* ctx) {
return AIO_IOPool_acquireJob(&ctx->base);
}
/* AIO_WritePool_enqueueAndReacquireWriteJob:
* Queues a write job for execution and acquires a new one.
* After execution `job`'s pointed value would change to the newly acquired job.
* Make sure to set `usedBufferSize` to the wanted length before call.
* The queued job shouldn't be used directly after queueing it. */
void AIO_WritePool_enqueueAndReacquireWriteJob(IOJob_t **job) {
AIO_IOPool_enqueueJob(*job);
*job = AIO_IOPool_acquireJob((IOPoolCtx_t *)(*job)->ctx);
}
/* AIO_WritePool_sparseWriteEnd:
* Ends sparse writes to the current file.
* Blocks on completion of all current write jobs before executing. */
void AIO_WritePool_sparseWriteEnd(WritePoolCtx_t* ctx) {
assert(ctx != NULL);
AIO_IOPool_join(&ctx->base);
AIO_fwriteSparseEnd(ctx->base.prefs, ctx->base.file, ctx->storedSkips);
ctx->storedSkips = 0;
}
/* AIO_WritePool_setFile:
* Sets the destination file for future writes in the pool.
* Requires completion of all queues write jobs and release of all otherwise acquired jobs.
* Also requires ending of sparse write if a previous file was used in sparse mode. */
void AIO_WritePool_setFile(WritePoolCtx_t* ctx, FILE* file) {
AIO_IOPool_setFile(&ctx->base, file);
assert(ctx->storedSkips == 0);
}
/* AIO_WritePool_getFile:
* Returns the file the writePool is currently set to write to. */
FILE* AIO_WritePool_getFile(const WritePoolCtx_t* ctx) {
return AIO_IOPool_getFile(&ctx->base);
}
/* AIO_WritePool_releaseIoJob:
* Releases an acquired job back to the pool. Doesn't execute the job. */
void AIO_WritePool_releaseIoJob(IOJob_t* job) {
AIO_IOPool_releaseIoJob(job);
}
/* AIO_WritePool_closeFile:
* Ends sparse write and closes the writePool's current file and sets the file to NULL.
* Requires completion of all queues write jobs and release of all otherwise acquired jobs. */
int AIO_WritePool_closeFile(WritePoolCtx_t* ctx) {
FILE* const dstFile = ctx->base.file;
assert(dstFile!=NULL || ctx->base.prefs->testMode!=0);
AIO_WritePool_sparseWriteEnd(ctx);
AIO_IOPool_setFile(&ctx->base, NULL);
return fclose(dstFile);
}
/* AIO_WritePool_executeWriteJob:
* Executes a write job synchronously. Can be used as a function for a thread pool. */
static void AIO_WritePool_executeWriteJob(void* opaque){
IOJob_t* const job = (IOJob_t*) opaque;
WritePoolCtx_t* const ctx = (WritePoolCtx_t*) job->ctx;
ctx->storedSkips = AIO_fwriteSparse(job->file, job->buffer, job->usedBufferSize, ctx->base.prefs, ctx->storedSkips);
AIO_IOPool_releaseIoJob(job);
}
/* AIO_WritePool_create:
* Allocates and sets and a new write pool including its included jobs. */
WritePoolCtx_t* AIO_WritePool_create(const FIO_prefs_t* prefs, size_t bufferSize) {
WritePoolCtx_t* const ctx = (WritePoolCtx_t*) malloc(sizeof(WritePoolCtx_t));
if(!ctx) EXM_THROW(100, "Allocation error : not enough memory");
AIO_IOPool_init(&ctx->base, prefs, AIO_WritePool_executeWriteJob, bufferSize);
ctx->storedSkips = 0;
return ctx;
}
/* AIO_WritePool_free:
* Frees and releases a writePool and its resources. Closes destination file if needs to. */
void AIO_WritePool_free(WritePoolCtx_t* ctx) {
/* Make sure we finish all tasks and then free the resources */
if(AIO_WritePool_getFile(ctx))
AIO_WritePool_closeFile(ctx);
AIO_IOPool_destroy(&ctx->base);
assert(ctx->storedSkips==0);
free(ctx);
}
/* AIO_WritePool_setAsync:
* Allows (de)activating async mode, to be used when the expected overhead
* of asyncio costs more than the expected gains. */
void AIO_WritePool_setAsync(WritePoolCtx_t* ctx, int async) {
AIO_IOPool_setThreaded(&ctx->base, async);
}
/* ***********************************
* ReadPool implementation
*************************************/
static void AIO_ReadPool_releaseAllCompletedJobs(ReadPoolCtx_t* ctx) {
int i;
for(i=0; i<ctx->completedJobsCount; i++) {
IOJob_t* job = (IOJob_t*) ctx->completedJobs[i];
AIO_IOPool_releaseIoJob(job);
}
ctx->completedJobsCount = 0;
}
static void AIO_ReadPool_addJobToCompleted(IOJob_t* job) {
ReadPoolCtx_t* const ctx = (ReadPoolCtx_t *)job->ctx;
AIO_IOPool_lockJobsMutex(&ctx->base);
assert(ctx->completedJobsCount < MAX_IO_JOBS);
ctx->completedJobs[ctx->completedJobsCount++] = job;
if(AIO_IOPool_threadPoolActive(&ctx->base)) {
ZSTD_pthread_cond_signal(&ctx->jobCompletedCond);
}
AIO_IOPool_unlockJobsMutex(&ctx->base);
}
/* AIO_ReadPool_findNextWaitingOffsetCompletedJob_locked:
* Looks through the completed jobs for a job matching the waitingOnOffset and returns it,
* if job wasn't found returns NULL.
* IMPORTANT: assumes ioJobsMutex is locked. */
static IOJob_t* AIO_ReadPool_findNextWaitingOffsetCompletedJob_locked(ReadPoolCtx_t* ctx) {
IOJob_t *job = NULL;
int i;
/* This implementation goes through all completed jobs and looks for the one matching the next offset.
* While not strictly needed for a single threaded reader implementation (as in such a case we could expect
* reads to be completed in order) this implementation was chosen as it better fits other asyncio
* interfaces (such as io_uring) that do not provide promises regarding order of completion. */
for (i=0; i<ctx->completedJobsCount; i++) {
job = (IOJob_t *) ctx->completedJobs[i];
if (job->offset == ctx->waitingOnOffset) {
ctx->completedJobs[i] = ctx->completedJobs[--ctx->completedJobsCount];
return job;
}
}
return NULL;
}
/* AIO_ReadPool_numReadsInFlight:
* Returns the number of IO read jobs currently in flight. */
static size_t AIO_ReadPool_numReadsInFlight(ReadPoolCtx_t* ctx) {
const int jobsHeld = (ctx->currentJobHeld==NULL ? 0 : 1);
return (size_t)(ctx->base.totalIoJobs - (ctx->base.availableJobsCount + ctx->completedJobsCount + jobsHeld));
}
/* AIO_ReadPool_getNextCompletedJob:
* Returns a completed IOJob_t for the next read in line based on waitingOnOffset and advances waitingOnOffset.
* Would block. */
static IOJob_t* AIO_ReadPool_getNextCompletedJob(ReadPoolCtx_t* ctx) {
IOJob_t *job = NULL;
AIO_IOPool_lockJobsMutex(&ctx->base);
job = AIO_ReadPool_findNextWaitingOffsetCompletedJob_locked(ctx);
/* As long as we didn't find the job matching the next read, and we have some reads in flight continue waiting */
while (!job && (AIO_ReadPool_numReadsInFlight(ctx) > 0)) {
assert(ctx->base.threadPool != NULL); /* we shouldn't be here if we work in sync mode */
ZSTD_pthread_cond_wait(&ctx->jobCompletedCond, &ctx->base.ioJobsMutex);
job = AIO_ReadPool_findNextWaitingOffsetCompletedJob_locked(ctx);
}
if(job) {
assert(job->offset == ctx->waitingOnOffset);
ctx->waitingOnOffset += job->usedBufferSize;
}
AIO_IOPool_unlockJobsMutex(&ctx->base);
return job;
}
/* AIO_ReadPool_executeReadJob:
* Executes a read job synchronously. Can be used as a function for a thread pool. */
static void AIO_ReadPool_executeReadJob(void* opaque){
IOJob_t* const job = (IOJob_t*) opaque;
ReadPoolCtx_t* const ctx = (ReadPoolCtx_t *)job->ctx;
if(ctx->reachedEof) {
job->usedBufferSize = 0;
AIO_ReadPool_addJobToCompleted(job);
return;
}
job->usedBufferSize = fread(job->buffer, 1, job->bufferSize, job->file);
if(job->usedBufferSize < job->bufferSize) {
if(ferror(job->file)) {
EXM_THROW(37, "Read error");
} else if(feof(job->file)) {
ctx->reachedEof = 1;
} else {
EXM_THROW(37, "Unexpected short read");
}
}
AIO_ReadPool_addJobToCompleted(job);
}
static void AIO_ReadPool_enqueueRead(ReadPoolCtx_t* ctx) {
IOJob_t* const job = AIO_IOPool_acquireJob(&ctx->base);
job->offset = ctx->nextReadOffset;
ctx->nextReadOffset += job->bufferSize;
AIO_IOPool_enqueueJob(job);
}
static void AIO_ReadPool_startReading(ReadPoolCtx_t* ctx) {
while(ctx->base.availableJobsCount) {
AIO_ReadPool_enqueueRead(ctx);
}
}
/* AIO_ReadPool_setFile:
* Sets the source file for future read in the pool. Initiates reading immediately if file is not NULL.
* Waits for all current enqueued tasks to complete if a previous file was set. */
void AIO_ReadPool_setFile(ReadPoolCtx_t* ctx, FILE* file) {
assert(ctx!=NULL);
AIO_IOPool_join(&ctx->base);
AIO_ReadPool_releaseAllCompletedJobs(ctx);
if (ctx->currentJobHeld) {
AIO_IOPool_releaseIoJob((IOJob_t *)ctx->currentJobHeld);
ctx->currentJobHeld = NULL;
}
AIO_IOPool_setFile(&ctx->base, file);
ctx->nextReadOffset = 0;
ctx->waitingOnOffset = 0;
ctx->srcBuffer = ctx->coalesceBuffer;
ctx->srcBufferLoaded = 0;
ctx->reachedEof = 0;
if(file != NULL)
AIO_ReadPool_startReading(ctx);
}
/* AIO_ReadPool_create:
* Allocates and sets and a new readPool including its included jobs.
* bufferSize should be set to the maximal buffer we want to read at a time, will also be used
* as our basic read size. */
ReadPoolCtx_t* AIO_ReadPool_create(const FIO_prefs_t* prefs, size_t bufferSize) {
ReadPoolCtx_t* const ctx = (ReadPoolCtx_t*) malloc(sizeof(ReadPoolCtx_t));
if(!ctx) EXM_THROW(100, "Allocation error : not enough memory");
AIO_IOPool_init(&ctx->base, prefs, AIO_ReadPool_executeReadJob, bufferSize);
ctx->coalesceBuffer = (U8*) malloc(bufferSize * 2);
if(!ctx->coalesceBuffer) EXM_THROW(100, "Allocation error : not enough memory");
ctx->srcBuffer = ctx->coalesceBuffer;
ctx->srcBufferLoaded = 0;
ctx->completedJobsCount = 0;
ctx->currentJobHeld = NULL;
if(ctx->base.threadPool)
if (ZSTD_pthread_cond_init(&ctx->jobCompletedCond, NULL))
EXM_THROW(103,"Failed creating jobCompletedCond cond");
return ctx;
}
/* AIO_ReadPool_free:
* Frees and releases a readPool and its resources. Closes source file. */
void AIO_ReadPool_free(ReadPoolCtx_t* ctx) {
if(AIO_ReadPool_getFile(ctx))
AIO_ReadPool_closeFile(ctx);
if(ctx->base.threadPool)
ZSTD_pthread_cond_destroy(&ctx->jobCompletedCond);
AIO_IOPool_destroy(&ctx->base);
free(ctx->coalesceBuffer);
free(ctx);
}
/* AIO_ReadPool_consumeBytes:
* Consumes byes from srcBuffer's beginning and updates srcBufferLoaded accordingly. */
void AIO_ReadPool_consumeBytes(ReadPoolCtx_t* ctx, size_t n) {
assert(n <= ctx->srcBufferLoaded);
ctx->srcBufferLoaded -= n;
ctx->srcBuffer += n;
}
/* AIO_ReadPool_releaseCurrentlyHeldAndGetNext:
* Release the current held job and get the next one, returns NULL if no next job available. */
static IOJob_t* AIO_ReadPool_releaseCurrentHeldAndGetNext(ReadPoolCtx_t* ctx) {
if (ctx->currentJobHeld) {
AIO_IOPool_releaseIoJob((IOJob_t *)ctx->currentJobHeld);
ctx->currentJobHeld = NULL;
AIO_ReadPool_enqueueRead(ctx);
}
ctx->currentJobHeld = AIO_ReadPool_getNextCompletedJob(ctx);
return (IOJob_t*) ctx->currentJobHeld;
}
/* AIO_ReadPool_fillBuffer:
* Tries to fill the buffer with at least n or jobBufferSize bytes (whichever is smaller).
* Returns if srcBuffer has at least the expected number of bytes loaded or if we've reached the end of the file.
* Return value is the number of bytes added to the buffer.
* Note that srcBuffer might have up to 2 times jobBufferSize bytes. */
size_t AIO_ReadPool_fillBuffer(ReadPoolCtx_t* ctx, size_t n) {
IOJob_t *job;
int useCoalesce = 0;
if(n > ctx->base.jobBufferSize)
n = ctx->base.jobBufferSize;
/* We are good, don't read anything */
if (ctx->srcBufferLoaded >= n)
return 0;
/* We still have bytes loaded, but not enough to satisfy caller. We need to get the next job
* and coalesce the remaining bytes with the next job's buffer */
if (ctx->srcBufferLoaded > 0) {
useCoalesce = 1;
memcpy(ctx->coalesceBuffer, ctx->srcBuffer, ctx->srcBufferLoaded);
ctx->srcBuffer = ctx->coalesceBuffer;
}
/* Read the next chunk */
job = AIO_ReadPool_releaseCurrentHeldAndGetNext(ctx);
if(!job)
return 0;
if(useCoalesce) {
assert(ctx->srcBufferLoaded + job->usedBufferSize <= 2*ctx->base.jobBufferSize);
memcpy(ctx->coalesceBuffer + ctx->srcBufferLoaded, job->buffer, job->usedBufferSize);
ctx->srcBufferLoaded += job->usedBufferSize;
}
else {
ctx->srcBuffer = (U8 *) job->buffer;
ctx->srcBufferLoaded = job->usedBufferSize;
}
return job->usedBufferSize;
}
/* AIO_ReadPool_consumeAndRefill:
* Consumes the current buffer and refills it with bufferSize bytes. */
size_t AIO_ReadPool_consumeAndRefill(ReadPoolCtx_t* ctx) {
AIO_ReadPool_consumeBytes(ctx, ctx->srcBufferLoaded);
return AIO_ReadPool_fillBuffer(ctx, ctx->base.jobBufferSize);
}
/* AIO_ReadPool_getFile:
* Returns the current file set for the read pool. */
FILE* AIO_ReadPool_getFile(const ReadPoolCtx_t* ctx) {
return AIO_IOPool_getFile(&ctx->base);
}
/* AIO_ReadPool_closeFile:
* Closes the current set file. Waits for all current enqueued tasks to complete and resets state. */
int AIO_ReadPool_closeFile(ReadPoolCtx_t* ctx) {
FILE* const file = AIO_ReadPool_getFile(ctx);
AIO_ReadPool_setFile(ctx, NULL);
return fclose(file);
}
/* AIO_ReadPool_setAsync:
* Allows (de)activating async mode, to be used when the expected overhead
* of asyncio costs more than the expected gains. */
void AIO_ReadPool_setAsync(ReadPoolCtx_t* ctx, int async) {
AIO_IOPool_setThreaded(&ctx->base, async);
}
