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/*
* Declarations for background jobs
*
* Copyright (c) 2011 IBM Corp.
* Copyright (c) 2012, 2018 Red Hat, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef JOB_H
#define JOB_H
#include "qapi/qapi-types-block-core.h"
#include "qemu/queue.h"
typedef struct JobDriver JobDriver;
/**
* Long-running operation.
*/
typedef struct Job {
/** The ID of the job. May be NULL for internal jobs. */
char *id;
/** The type of this job. */
const JobDriver *driver;
/** Reference count of the block job */
int refcnt;
/** Current state; See @JobStatus for details. */
JobStatus status;
/** AioContext to run the job coroutine in */
AioContext *aio_context;
/**
* Set to true if the job should cancel itself. The flag must
* always be tested just before toggling the busy flag from false
* to true. After a job has been cancelled, it should only yield
* if #aio_poll will ("sooner or later") reenter the coroutine.
*/
bool cancelled;
/** Set to true when the job has deferred work to the main loop. */
bool deferred_to_main_loop;
/** Element of the list of jobs */
QLIST_ENTRY(Job) job_list;
} Job;
/**
* Callbacks and other information about a Job driver.
*/
struct JobDriver {
/** Derived Job struct size */
size_t instance_size;
/** Enum describing the operation */
JobType job_type;
/** Called when the job is freed */
void (*free)(Job *job);
};
/**
* Create a new long-running job and return it.
*
* @job_id: The id of the newly-created job, or %NULL for internal jobs
* @driver: The class object for the newly-created job.
* @ctx: The AioContext to run the job coroutine in.
* @errp: Error object.
*/
void *job_create(const char *job_id, const JobDriver *driver, AioContext *ctx,
Error **errp);
/**
* Add a reference to Job refcnt, it will be decreased with job_unref, and then
* be freed if it comes to be the last reference.
*/
void job_ref(Job *job);
/**
* Release a reference that was previously acquired with job_ref() or
* job_create(). If it's the last reference to the object, it will be freed.
*/
void job_unref(Job *job);
/** Returns the JobType of a given Job. */
JobType job_type(const Job *job);
/** Returns the enum string for the JobType of a given Job. */
const char *job_type_str(const Job *job);
/** Returns whether the job is scheduled for cancellation. */
bool job_is_cancelled(Job *job);
/**
* Get the next element from the list of block jobs after @job, or the
* first one if @job is %NULL.
*
* Returns the requested job, or %NULL if there are no more jobs left.
*/
Job *job_next(Job *job);
/**
* Get the job identified by @id (which must not be %NULL).
*
* Returns the requested job, or %NULL if it doesn't exist.
*/
Job *job_get(const char *id);
/**
* Check whether the verb @verb can be applied to @job in its current state.
* Returns 0 if the verb can be applied; otherwise errp is set and -EPERM
* returned.
*/
int job_apply_verb(Job *job, JobVerb verb, Error **errp);
typedef void JobDeferToMainLoopFn(Job *job, void *opaque);
/**
* @job: The job
* @fn: The function to run in the main loop
* @opaque: The opaque value that is passed to @fn
*
* This function must be called by the main job coroutine just before it
* returns. @fn is executed in the main loop with the job AioContext acquired.
*
* Block jobs must call bdrv_unref(), bdrv_close(), and anything that uses
* bdrv_drain_all() in the main loop.
*
* The @job AioContext is held while @fn executes.
*/
void job_defer_to_main_loop(Job *job, JobDeferToMainLoopFn *fn, void *opaque);
/* TODO To be removed from the public interface */
void job_state_transition(Job *job, JobStatus s1);
#endif
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