[vlc-devel] [PATCH 3/6] preparser: use vlc_executor_t
Steve Lhomme
robux4 at ycbcr.xyz
Tue Sep 8 09:42:38 CEST 2020
On 2020-09-07 17:40, Romain Vimont wrote:
> Replace the background_worker by an executor.
> ---
> src/preparser/preparser.c | 401 ++++++++++++++++++++++++--------------
> 1 file changed, 251 insertions(+), 150 deletions(-)
>
> diff --git a/src/preparser/preparser.c b/src/preparser/preparser.c
> index 723feb96dc..78fd31a626 100644
> --- a/src/preparser/preparser.c
> +++ b/src/preparser/preparser.c
> @@ -24,8 +24,8 @@
>
> #include <vlc_common.h>
> #include <vlc_atomic.h>
> +#include <vlc_executor.h>
>
> -#include "misc/background_worker.h"
> #include "input/input_interface.h"
> #include "input/input_internal.h"
> #include "preparser.h"
> @@ -35,222 +35,299 @@ struct input_preparser_t
> {
> vlc_object_t* owner;
> input_fetcher_t* fetcher;
> - struct background_worker* worker;
> + vlc_executor_t *executor;
> + vlc_tick_t default_timeout;
> atomic_bool deactivated;
> +
> + vlc_mutex_t lock;
> + struct vlc_list submitted_tasks; /**< list of struct task */
I understand the goal of the executor API is to be simpler that the
background worker but...
> };
>
> -typedef struct input_preparser_req_t
> +struct task
> {
> + input_preparser_t *preparser;
> input_item_t *item;
> input_item_meta_request_option_t options;
> const input_preparser_callbacks_t *cbs;
> void *userdata;
> - vlc_atomic_rc_t rc;
> -} input_preparser_req_t;
> + void *id;
> + vlc_tick_t timeout;
>
> -typedef struct input_preparser_task_t
> -{
> - input_preparser_req_t *req;
> - input_preparser_t* preparser;
> - int preparse_status;
> input_item_parser_id_t *parser;
> - atomic_int state;
> - atomic_bool done;
> -} input_preparser_task_t;
> -
> -static input_preparser_req_t *ReqCreate(input_item_t *item,
> - input_item_meta_request_option_t options,
> - const input_preparser_callbacks_t *cbs,
> - void *userdata)
> +
> + vlc_mutex_t lock;
> + vlc_cond_t cond_ended;
> + bool preparse_ended;
> + int preparse_status;
> + bool fetch_ended;
> +
> + atomic_bool interrupted;
> +
> + struct vlc_runnable runnable; /**< to be passed to the executor */
> +
> + struct vlc_list node; /**< node of input_preparser_t.submitted_tasks */
> +};
> +
> +static void RunnableRun(void *);
> +
> +static struct task *
> +TaskNew(input_preparser_t *preparser, input_item_t *item,
> + input_item_meta_request_option_t options,
> + const input_preparser_callbacks_t *cbs, void *userdata,
> + void *id, vlc_tick_t timeout)
> {
> - input_preparser_req_t *req = malloc(sizeof(*req));
> - if (unlikely(!req))
> + assert(timeout >= 0);
> +
> + struct task *task = malloc(sizeof(*task));
> + if (!task)
> return NULL;
>
> - req->item = item;
> - req->options = options;
> - req->cbs = cbs;
> - req->userdata = userdata;
> - vlc_atomic_rc_init(&req->rc);
> + task->preparser = preparser;
> + task->item = item;
> + task->options = options;
> + task->cbs = cbs;
> + task->userdata = userdata;
> + task->id = id;
> + task->timeout = timeout;
>
> input_item_Hold(item);
>
> - return req;
> + task->parser = NULL;
> + vlc_mutex_init(&task->lock);
> + vlc_cond_init(&task->cond_ended);
> + task->preparse_ended = false;
> + task->preparse_status = ITEM_PREPARSE_SKIPPED;
> + task->fetch_ended = false;
> +
> + atomic_init(&task->interrupted, false);
> +
> + task->runnable.run = RunnableRun;
> + task->runnable.userdata = task;
> +
> + return task;
> }
>
> -static void ReqHold(input_preparser_req_t *req)
> +static void
> +TaskDelete(struct task *task)
> {
> - vlc_atomic_rc_inc(&req->rc);
> + input_item_Release(task->item);
> + free(task);
> }
>
> -static void ReqRelease(input_preparser_req_t *req)
> +static void
> +PreparserAddTask(input_preparser_t *preparser, struct task *task)
> {
> - if (vlc_atomic_rc_dec(&req->rc))
> - {
> - input_item_Release(req->item);
> - free(req);
> - }
> + vlc_mutex_lock(&preparser->lock);
> + vlc_list_append(&task->node, &preparser->submitted_tasks);
> + vlc_mutex_unlock(&preparser->lock);
> }
>
> -static void OnParserEnded(input_item_t *item, int status, void *task_)
> +static void
> +PreparserRemoveTask(input_preparser_t *preparser, struct task *task)
> {
> - VLC_UNUSED(item);
> - input_preparser_task_t* task = task_;
> -
> - atomic_store( &task->state, status );
> - atomic_store( &task->done, true );
> - background_worker_RequestProbe( task->preparser->worker );
> + vlc_mutex_lock(&preparser->lock);
> + vlc_list_remove(&task->node);
> + vlc_mutex_unlock(&preparser->lock);
> }
>
> -static void OnParserSubtreeAdded(input_item_t *item, input_item_node_t *subtree,
> - void *task_)
> +static void
> +NotifyPreparseEnded(struct task *task)
> {
> - VLC_UNUSED(item);
> - input_preparser_task_t* task = task_;
> - input_preparser_req_t *req = task->req;
> -
> - if (req->cbs && req->cbs->on_subtree_added)
> - req->cbs->on_subtree_added(req->item, subtree, req->userdata);
> + if (task->cbs && task->cbs->on_preparse_ended)
> + task->cbs->on_preparse_ended(task->item, task->preparse_status,
> + task->userdata);
> }
>
> -static int PreparserOpenInput( void* preparser_, void* req_, void** out )
> +static void
> +OnParserEnded(input_item_t *item, int status, void *task_)
> {
> - input_preparser_t* preparser = preparser_;
> - input_preparser_req_t *req = req_;
> - input_preparser_task_t* task = malloc( sizeof *task );
> -
> - if( unlikely( !task ) )
> - goto error;
> -
> - static const input_item_parser_cbs_t cbs = {
> - .on_ended = OnParserEnded,
> - .on_subtree_added = OnParserSubtreeAdded,
> - };
> -
> - atomic_init( &task->state, VLC_ETIMEOUT );
> - atomic_init( &task->done, false );
> -
> - task->preparser = preparser_;
> - task->req = req;
> - task->preparse_status = -1;
> - task->parser = input_item_Parse( req->item, preparser->owner, &cbs,
> - task );
> - if( !task->parser )
> - goto error;
> + VLC_UNUSED(item);
> + struct task *task = task_;
>
> - *out = task;
> + if (atomic_load(&task->interrupted))
> + /*
> + * On interruption, the call to input_item_parser_id_Release() may
> + * trigger this "parser ended" callback. Ignore it.
> + */
> + return;
>
> - return VLC_SUCCESS;
> + vlc_mutex_lock(&task->lock);
> + assert(!task->preparse_ended);
> + task->preparse_status = status == VLC_SUCCESS ? ITEM_PREPARSE_DONE
> + : ITEM_PREPARSE_FAILED;
> + task->preparse_ended = true;
> + vlc_mutex_unlock(&task->lock);
>
> -error:
> - free( task );
> - if (req->cbs && req->cbs->on_preparse_ended)
> - req->cbs->on_preparse_ended(req->item, ITEM_PREPARSE_FAILED, req->userdata);
> - return VLC_EGENERIC;
> + vlc_cond_signal(&task->cond_ended);
> }
>
> -static int PreparserProbeInput( void* preparser_, void* task_ )
> +static void
> +OnParserSubtreeAdded(input_item_t *item, input_item_node_t *subtree,
> + void *task_)
> {
> - input_preparser_task_t* task = task_;
> - return atomic_load( &task->done );
> - VLC_UNUSED( preparser_ );
> + VLC_UNUSED(item);
> + struct task *task = task_;
> +
> + if (task->cbs && task->cbs->on_subtree_added)
> + task->cbs->on_subtree_added(task->item, subtree, task->userdata);
> }
>
> -static void on_art_fetch_ended(input_item_t *item, bool fetched, void *userdata)
> +static void
> +OnArtFetchEnded(input_item_t *item, bool fetched, void *userdata)
> {
> VLC_UNUSED(item);
> VLC_UNUSED(fetched);
> - input_preparser_task_t *task = userdata;
> - input_preparser_req_t *req = task->req;
>
> - input_item_SetPreparsed(req->item, true);
> + struct task *task = userdata;
>
> - if (req->cbs && req->cbs->on_preparse_ended)
> - req->cbs->on_preparse_ended(req->item, task->preparse_status, req->userdata);
> + vlc_mutex_lock(&task->lock);
> + assert(!task->fetch_ended);
> + task->fetch_ended = true;
> + vlc_mutex_unlock(&task->lock);
>
> - ReqRelease(req);
> - free(task);
> + vlc_cond_signal(&task->cond_ended);
> }
>
> static const input_fetcher_callbacks_t input_fetcher_callbacks = {
> - .on_art_fetch_ended = on_art_fetch_ended,
> + .on_art_fetch_ended = OnArtFetchEnded,
> };
>
> -static void PreparserCloseInput( void* preparser_, void* task_ )
> +static void
> +Parse(struct task *task, vlc_tick_t deadline)
> {
> - input_preparser_task_t* task = task_;
> - input_preparser_req_t *req = task->req;
> -
> - input_preparser_t* preparser = preparser_;
> - input_item_t* item = req->item;
> + static const input_item_parser_cbs_t cbs = {
> + .on_ended = OnParserEnded,
> + .on_subtree_added = OnParserSubtreeAdded,
> + };
>
> - int status;
> - switch( atomic_load( &task->state ) )
> + vlc_object_t *obj = task->preparser->owner;
> + task->parser = input_item_Parse(task->item, obj, &cbs, task);
> + if (!task->parser)
> {
> - case VLC_SUCCESS:
> - status = ITEM_PREPARSE_DONE;
> - break;
> - case VLC_ETIMEOUT:
> - status = ITEM_PREPARSE_TIMEOUT;
> - break;
> - default:
> - status = ITEM_PREPARSE_FAILED;
> - break;
> + task->preparse_status = ITEM_PREPARSE_FAILED;
> + return;
> }
>
> - input_item_parser_id_Release( task->parser );
> -
> - if( preparser->fetcher && (req->options & META_REQUEST_OPTION_FETCH_ANY) )
> + /* Wait until the end of parsing */
> + vlc_mutex_lock(&task->lock);
> + if (deadline == VLC_TICK_INVALID)
> + {
> + while (!task->preparse_ended)
> + vlc_cond_wait(&task->cond_ended, &task->lock);
> + }
> + else
> {
> - task->preparse_status = status;
> - ReqHold(task->req);
> - if (!input_fetcher_Push(preparser->fetcher, item,
> - req->options & META_REQUEST_OPTION_FETCH_ANY,
> - &input_fetcher_callbacks, task))
> + bool timeout = false;
> + while (!task->preparse_ended && !timeout)
> + timeout =
> + vlc_cond_timedwait(&task->cond_ended, &task->lock, deadline);
> +
> + if (timeout)
> {
> - return;
> + task->preparse_status = ITEM_PREPARSE_TIMEOUT;
> + atomic_store(&task->interrupted, true);
> }
> - ReqRelease(task->req);
> }
> + vlc_mutex_unlock(&task->lock);
>
> - free(task);
> + /* This call also interrupts the parsing if it is still running */
> + input_item_parser_id_Release(task->parser);
> +}
> +
> +static void
> +Fetch(struct task *task)
> +{
> + input_fetcher_t *fetcher = task->preparser->fetcher;
> + if (!fetcher || !(task->options & META_REQUEST_OPTION_FETCH_ANY))
> + return;
> +
> + int ret =
> + input_fetcher_Push(fetcher, task->item,
> + task->options & META_REQUEST_OPTION_FETCH_ANY,
> + &input_fetcher_callbacks, task);
> + if (ret != VLC_SUCCESS)
> + return;
> +
> + /* Wait until the end of fetching (fetching is not interruptible) */
> + vlc_mutex_lock(&task->lock);
> + while (!task->fetch_ended)
> + vlc_cond_wait(&task->cond_ended, &task->lock);
> + vlc_mutex_unlock(&task->lock);
> +}
> +
> +static void
> +RunnableRun(void *userdata)
> +{
> + struct task *task = userdata;
> +
> + vlc_tick_t deadline = task->timeout ? vlc_tick_now() + task->timeout
> + : VLC_TICK_INVALID;
> +
> + if (atomic_load(&task->interrupted))
> + goto end;
>
> - input_item_SetPreparsed( item, true );
> - if (req->cbs && req->cbs->on_preparse_ended)
> - req->cbs->on_preparse_ended(req->item, status, req->userdata);
> + Parse(task, deadline);
> +
> + if (atomic_load(&task->interrupted))
> + goto end;
> +
> + Fetch(task);
> +
> + if (atomic_load(&task->interrupted))
> + goto end;
> +
> + input_item_SetPreparsed(task->item, true);
> +
> +end:
> + NotifyPreparseEnded(task);
> + input_preparser_t *preparser = task->preparser;
> + PreparserRemoveTask(preparser, task);
> + TaskDelete(task);
> }
>
> -static void ReqHoldVoid(void *item) { ReqHold(item); }
> -static void ReqReleaseVoid(void *item) { ReqRelease(item); }
> +static void
> +Interrupt(struct task *task)
> +{
> + assert(!atomic_load(&task->interrupted));
> + atomic_store(&task->interrupted, true);
> +
> + /* Wake up the preparser cond_wait */
> + vlc_mutex_lock(&task->lock);
> + task->preparse_status = ITEM_PREPARSE_TIMEOUT;
> + task->preparse_ended = true;
> + vlc_mutex_unlock(&task->lock);
> + vlc_cond_signal(&task->cond_ended);
> +}
>
> input_preparser_t* input_preparser_New( vlc_object_t *parent )
> {
> input_preparser_t* preparser = malloc( sizeof *preparser );
> + if (!preparser)
> + return NULL;
>
> - struct background_worker_config conf = {
> - .default_timeout = VLC_TICK_FROM_MS(var_InheritInteger( parent, "preparse-timeout" )),
> - .max_threads = var_InheritInteger( parent, "preparse-threads" ),
> - .pf_start = PreparserOpenInput,
> - .pf_probe = PreparserProbeInput,
> - .pf_stop = PreparserCloseInput,
> - .pf_release = ReqReleaseVoid,
> - .pf_hold = ReqHoldVoid
> - };
> -
> -
> - if( likely( preparser ) )
> - preparser->worker = background_worker_New( preparser, &conf );
> + int max_threads = var_InheritInteger(parent, "preparse-threads");
> + if (max_threads < 1)
> + max_threads = 1;
>
> - if( unlikely( !preparser || !preparser->worker ) )
> + preparser->executor = vlc_executor_New(max_threads);
> + if (!preparser->executor)
> {
> - free( preparser );
> + free(preparser);
> return NULL;
> }
>
> + preparser->default_timeout =
> + VLC_TICK_FROM_MS(var_InheritInteger(parent, "preparse-timeout"));
> + if (preparser->default_timeout < 0)
> + preparser->default_timeout = 0;
> +
> preparser->owner = parent;
> preparser->fetcher = input_fetcher_New( parent );
> atomic_init( &preparser->deactivated, false );
>
> + vlc_mutex_init(&preparser->lock);
> + vlc_list_init(&preparser->submitted_tasks);
> +
> if( unlikely( !preparser->fetcher ) )
> msg_Warn( parent, "unable to create art fetcher" );
>
> @@ -260,7 +337,7 @@ input_preparser_t* input_preparser_New( vlc_object_t *parent )
> void input_preparser_Push( input_preparser_t *preparser,
> input_item_t *item, input_item_meta_request_option_t i_options,
> const input_preparser_callbacks_t *cbs, void *cbs_userdata,
> - int timeout, void *id )
> + int timeout_ms, void *id )
> {
> if( atomic_load( &preparser->deactivated ) )
> return;
> @@ -287,14 +364,14 @@ void input_preparser_Push( input_preparser_t *preparser,
> return;
> }
>
> - struct input_preparser_req_t *req = ReqCreate(item, i_options,
> - cbs, cbs_userdata);
> + vlc_tick_t timeout = timeout_ms == -1 ? preparser->default_timeout
> + : VLC_TICK_FROM_MS(timeout_ms);
> + struct task *task =
> + TaskNew(preparser, item, i_options, cbs, cbs_userdata, id, timeout);
>
> - if (background_worker_Push(preparser->worker, req, id, timeout))
> - if (req->cbs && cbs->on_preparse_ended)
> - cbs->on_preparse_ended(item, ITEM_PREPARSE_FAILED, cbs_userdata);
> + PreparserAddTask(preparser, task);
>
> - ReqRelease(req);
> + vlc_executor_Submit(preparser->executor, &task->runnable);
> }
>
> void input_preparser_fetcher_Push( input_preparser_t *preparser,
> @@ -308,18 +385,42 @@ void input_preparser_fetcher_Push( input_preparser_t *preparser,
>
> void input_preparser_Cancel( input_preparser_t *preparser, void *id )
> {
> - background_worker_Cancel( preparser->worker, id );
> + vlc_mutex_lock(&preparser->lock);
> +
> + struct task *task;
> + vlc_list_foreach(task, &preparser->submitted_tasks, node)
> + {
> + if (!id || task->id == id)
> + {
> + bool canceled =
> + vlc_executor_Cancel(preparser->executor, &task->runnable);
> + if (canceled)
> + {
> + NotifyPreparseEnded(task);
> + vlc_list_remove(&task->node);
> + TaskDelete(task);
> + }
> + else
> + /* The task will be finished after run() */
> + Interrupt(task);
> + }
> + }
> +
> + vlc_mutex_unlock(&preparser->lock);
..this is a lot of error-prone boilerplate code that has to be written
in all executor users.
> }
>
> void input_preparser_Deactivate( input_preparser_t* preparser )
> {
> atomic_store( &preparser->deactivated, true );
> - background_worker_Cancel( preparser->worker, NULL );
> + input_preparser_Cancel(preparser, NULL);
> }
>
> void input_preparser_Delete( input_preparser_t *preparser )
> {
> - background_worker_Delete( preparser->worker );
> + /* In case input_preparser_Deactivate() has not been called */
> + input_preparser_Cancel(preparser, NULL);
> +
> + vlc_executor_Delete(preparser->executor);
>
> if( preparser->fetcher )
> input_fetcher_Delete( preparser->fetcher );
> --
> 2.28.0
>
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