Data Structures | Macros | Functions | Variables
Eina_Future

Cancels a future. More...

Data Structures

struct  _Eina_Future_Race_Result
 The struct that is used to store the race result. More...
 

Macros

#define EINA_FUTURE_SENTINEL   ((void *)(unsigned long)-1)
 Used by eina_promise_race_array() and eina_promise_all_array() and friends to flag the end of the array. More...
 
#define eina_promise_race(...)   eina_promise_race_array((Eina_Future *[]){__VA_ARGS__, EINA_FUTURE_SENTINEL})
 A syntactic sugar over eina_promise_race_array(). More...
 
#define eina_future_race(...)   eina_future_race_array((Eina_Future *[]){__VA_ARGS__, EINA_FUTURE_SENTINEL})
 A syntactic sugar over eina_future_race_array(). More...
 
#define eina_future_all(...)   eina_future_all_array((Eina_Future *[]){__VA_ARGS__, EINA_FUTURE_SENTINEL})
 A syntactic sugar over eina_future_all_array(). More...
 
#define eina_promise_all(...)   eina_promise_all_array((Eina_Future *[]){__VA_ARGS__, EINA_FUTURE_SENTINEL})
 A syntactic sugar over eina_promise_all_array(). More...
 
#define eina_future_cb_easy(...)   eina_future_cb_easy_from_desc((Eina_Future_Cb_Easy_Desc){__VA_ARGS__})
 A syntactic sugar over eina_future_cb_easy_from_desc(). More...
 
#define eina_future_chain(_prev, ...)   eina_future_chain_array(_prev, (Eina_Future_Desc[]){__VA_ARGS__, {.cb = NULL, .data = NULL}})
 A syntactic sugar over eina_future_chain_array(). More...
 
#define eina_future_then(_prev, ...)   eina_future_then_from_desc(_prev, (Eina_Future_Desc){__VA_ARGS__})
 A syntactic sugar over eina_future_then_from_desc(). More...
 
#define eina_future_cb_console(...)   eina_future_cb_console_from_desc((Eina_Future_Cb_Console_Desc){__VA_ARGS__})
 A syntactic sugar over eina_future_cb_console_from_desc(). More...
 
#define eina_future_cb_log_dbg(_prefix, _suffix)
 A syntactic sugar over eina_future_cb_log_from_desc(). More...
 
#define eina_future_cb_log_crit(_prefix, _suffix)
 A syntactic sugar over eina_future_cb_log_from_desc(). More...
 
#define eina_future_cb_log_err(_prefix, _suffix)
 A syntactic sugar over eina_future_cb_log_from_desc(). More...
 
#define eina_future_cb_log_info(_prefix, _suffix)
 A syntactic sugar over eina_future_cb_log_from_desc(). More...
 
#define eina_future_cb_log_warn(_prefix, _suffix)
 A syntactic sugar over eina_future_cb_log_from_desc(). More...
 
#define eina_future_then_easy(_prev, ...)   eina_future_then_from_desc(_prev, eina_future_cb_easy(__VA_ARGS__))
 A syntactic sugar over eina_future_then() and eina_future_cb_easy(). More...
 
#define eina_future_chain_easy(_prev, ...)   eina_future_chain_easy_array(_prev, (Eina_Future_Cb_Easy_Desc[]) {__VA_ARGS__, {NULL, NULL, NULL, NULL, NULL}})
 A syntactic sugar over eina_future_chain() and eina_future_cb_easy(). More...
 

Functions

void eina_future_cancel (Eina_Future *f)
 
void eina_future_desc_flush (Eina_Future_Desc *desc)
 Flushes an #Eina_Future_Desc. More...
 
void eina_future_cb_easy_desc_flush (Eina_Future_Cb_Easy_Desc *desc)
 Flushes an #Eina_Future_Cb_Easy_Desc. More...
 
Eina_Value eina_promise_as_value (Eina_Promise *p)
 Creates a new Eina_Value from a promise. More...
 
Eina_Value eina_future_as_value (Eina_Future *f)
 Creates an Eina_Value from a future. More...
 
Eina_Future * eina_future_new (Eina_Promise *p)
 Creates a new future. More...
 
Eina_Future * eina_future_resolved (Eina_Future_Scheduler *scheduler, Eina_Value value)
 Creates a new future that is already resolved to a value. More...
 
Eina_Future * eina_future_rejected (Eina_Future_Scheduler *scheduler, Eina_Error err)
 Creates a new future that is already rejected to a specified error. More...
 
Eina_Future * eina_future_then_from_desc (Eina_Future *prev, const Eina_Future_Desc desc)
 Register an Eina_Future_Desc to be used when the future is resolve/rejected. More...
 
Eina_Future_Desc eina_future_cb_log_from_desc (const Eina_Future_Cb_Log_Desc desc)
 Creates an Eina_Future_Desc that will log the previous future resolved value. More...
 
Eina_Future * eina_future_chain_array (Eina_Future *prev, const Eina_Future_Desc descs[])
 Creates a future chain. More...
 
Eina_Future * eina_future_chain_easy_array (Eina_Future *prev, const Eina_Future_Cb_Easy_Desc descs[])
 Wrapper around eina_future_chain_array() and eina_future_cb_easy_from_desc() More...
 
Eina_Future_Desc eina_future_cb_console_from_desc (const Eina_Future_Cb_Console_Desc desc)
 Creates an Eina_Future_Desc that will print the previous future resolved value. More...
 
Eina_Future_Desc eina_future_cb_ignore_error (Eina_Error err)
 Returns a #Eina_Future_Desc that ignores an error. More...
 
Eina_Future_Desc eina_future_cb_convert_to (const Eina_Value_Type *type)
 Creates an #Eina_Future_Desc which will convert the the received eina value to a given type. More...
 
Eina_Future_Desc eina_future_cb_easy_from_desc (const Eina_Future_Cb_Easy_Desc desc)
 Creates an #Eina_Future_Desc based on a #Eina_Future_Cb_Easy_Desc. More...
 
Eina_Promise * eina_promise_all_array (Eina_Future *array[])
 Creates an all promise. More...
 
Eina_Promise * eina_promise_race_array (Eina_Future *array[])
 Creates a race promise. More...
 
static Eina_Future * eina_future_all_array (Eina_Future *array[])
 Creates a future that will be resolved once all futures from array is resolved. More...
 
static Eina_Future * eina_future_race_array (Eina_Future *array[])
 Creates a future that will be resolved once a future array is resolved. More...
 

Variables

const Eina_Value_Struct_DescEINA_PROMISE_RACE_STRUCT_DESC
 A pointer to the race struct description, which is used by eina_promise_race_array();. More...
 
EAPI const Eina_Value_Struct_DescEINA_PROMISE_RACE_STRUCT_DESC = &RACE_STRUCT_DESC
 A pointer to the race struct description, which is used by eina_promise_race_array();. More...
 

Detailed Description

Cancels a future.

This function will cancel the whole future chain immediately (it will not be schedule to the next mainloop pass) and it will also cancel the promise linked against it. The Eina_Future_Cb will be called with an Eina_Value typed as EINA_VALUE_TYPE_ERROR, which its value will be ECANCELED

Parameters
[in,out]fThe future to cancel.

Macro Definition Documentation

◆ EINA_FUTURE_SENTINEL

#define EINA_FUTURE_SENTINEL   ((void *)(unsigned long)-1)

Used by eina_promise_race_array() and eina_promise_all_array() and friends to flag the end of the array.

See also
eina_promise_race_array()
eina_promise_all_array()

◆ eina_promise_race

#define eina_promise_race (   ...)    eina_promise_race_array((Eina_Future *[]){__VA_ARGS__, EINA_FUTURE_SENTINEL})

A syntactic sugar over eina_promise_race_array().

Usage:

promise = eina_promise_race(future1, future2, future3, future4);
See also
eina_promise_race_array()

◆ eina_future_race

#define eina_future_race (   ...)    eina_future_race_array((Eina_Future *[]){__VA_ARGS__, EINA_FUTURE_SENTINEL})

A syntactic sugar over eina_future_race_array().

Usage:

future = eina_future_race(future1, future2, future3, future4);
See also
eina_future_race_array()

◆ eina_future_all

#define eina_future_all (   ...)    eina_future_all_array((Eina_Future *[]){__VA_ARGS__, EINA_FUTURE_SENTINEL})

A syntactic sugar over eina_future_all_array().

Usage:

future = eina_future_all(future1, future2, future3, future4);
See also
eina_future_all_array()

◆ eina_promise_all

#define eina_promise_all (   ...)    eina_promise_all_array((Eina_Future *[]){__VA_ARGS__, EINA_FUTURE_SENTINEL})

A syntactic sugar over eina_promise_all_array().

Usage:

promise = eina_promise_all(future1, future2, future3, future4);
See also
eina_promise_all_array()

◆ eina_future_cb_easy

#define eina_future_cb_easy (   ...)    eina_future_cb_easy_from_desc((Eina_Future_Cb_Easy_Desc){__VA_ARGS__})

A syntactic sugar over eina_future_cb_easy_from_desc().

Usage:

future_desc = eina_future_cb_easy(_success_cb, _error_cb, _free_cb, EINA_VALUE_TYPE_INT, my_data);
See also
eina_future_cb_easy_from_desc()

◆ eina_future_chain

#define eina_future_chain (   _prev,
  ... 
)    eina_future_chain_array(_prev, (Eina_Future_Desc[]){__VA_ARGS__, {.cb = NULL, .data = NULL}})

A syntactic sugar over eina_future_chain_array().

Usage:

future = eina_future_chain(future, {.cb = _my_cb, .data = my_data}, {.cb = _my_another_cb, .data = NULL});
See also
eina_future_chain_array()

◆ eina_future_then

#define eina_future_then (   _prev,
  ... 
)    eina_future_then_from_desc(_prev, (Eina_Future_Desc){__VA_ARGS__})

A syntactic sugar over eina_future_then_from_desc().

Usage:

future = eina_future_then(future, _my_cb, my_data);
See also
eina_future_then_from_desc()
eina_future_then_easy()

◆ eina_future_cb_console

#define eina_future_cb_console (   ...)    eina_future_cb_console_from_desc((Eina_Future_Cb_Console_Desc){__VA_ARGS__})

A syntactic sugar over eina_future_cb_console_from_desc().

Usage:

desc = eina_future_cb_console(.prefix = "prefix", .suffix = "suffix");
See also
eina_future_cb_console_from_desc()

◆ eina_future_cb_log_dbg

#define eina_future_cb_log_dbg (   _prefix,
  _suffix 
)
Value:
__FUNCTION__, EINA_LOG_LEVEL_DBG, EINA_LOG_DOMAIN_DEFAULT, __LINE__})
Eina_Future_Desc eina_future_cb_log_from_desc(const Eina_Future_Cb_Log_Desc desc)
Creates an Eina_Future_Desc that will log the previous future resolved value.
Definition: eina_promise.c:1475
Debug log level.
Definition: eina_log.h:461
#define EINA_LOG_DOMAIN_DEFAULT
This macro defines the domain to use with the macros EINA_LOG_DOM_DBG(), EINA_LOG_DOM_INFO(), EINA_LOG_DOM_WARN(), EINA_LOG_DOM_ERR() and EINA_LOG_DOM_CRIT().
Definition: eina_log.h:284
This struct is used by eina_future_cb_log_from_desc() and its contents will be routed to eina_log_pri...
Definition: eina_promise.h:371

A syntactic sugar over eina_future_cb_log_from_desc().

This macro will set the following fields of the #Eina_Future_Cb_Log_Desc:

Usage:

desc = eina_future_cb_log_dbg(.prefix = "prefix", .suffix = "suffix");
See also
eina_future_cb_log_from_desc()

◆ eina_future_cb_log_crit

#define eina_future_cb_log_crit (   _prefix,
  _suffix 
)
Value:
Eina_Future_Desc eina_future_cb_log_from_desc(const Eina_Future_Cb_Log_Desc desc)
Creates an Eina_Future_Desc that will log the previous future resolved value.
Definition: eina_promise.c:1475
Critical log level.
Definition: eina_log.h:457
#define EINA_LOG_DOMAIN_DEFAULT
This macro defines the domain to use with the macros EINA_LOG_DOM_DBG(), EINA_LOG_DOM_INFO(), EINA_LOG_DOM_WARN(), EINA_LOG_DOM_ERR() and EINA_LOG_DOM_CRIT().
Definition: eina_log.h:284
This struct is used by eina_future_cb_log_from_desc() and its contents will be routed to eina_log_pri...
Definition: eina_promise.h:371

A syntactic sugar over eina_future_cb_log_from_desc().

This macro will set the following fields of the #Eina_Future_Cb_Log_Desc:

Usage:

desc = eina_future_cb_log_crit(.prefix = "prefix", .suffix = "suffix");
See also
eina_future_cb_log_from_desc()

◆ eina_future_cb_log_err

#define eina_future_cb_log_err (   _prefix,
  _suffix 
)
Value:
__FUNCTION__, EINA_LOG_LEVEL_ERR, EINA_LOG_DOMAIN_DEFAULT, __LINE__})
Error log level.
Definition: eina_log.h:458
Eina_Future_Desc eina_future_cb_log_from_desc(const Eina_Future_Cb_Log_Desc desc)
Creates an Eina_Future_Desc that will log the previous future resolved value.
Definition: eina_promise.c:1475
#define EINA_LOG_DOMAIN_DEFAULT
This macro defines the domain to use with the macros EINA_LOG_DOM_DBG(), EINA_LOG_DOM_INFO(), EINA_LOG_DOM_WARN(), EINA_LOG_DOM_ERR() and EINA_LOG_DOM_CRIT().
Definition: eina_log.h:284
This struct is used by eina_future_cb_log_from_desc() and its contents will be routed to eina_log_pri...
Definition: eina_promise.h:371

A syntactic sugar over eina_future_cb_log_from_desc().

This macro will set the following fields of the #Eina_Future_Cb_Log_Desc:

Usage:

desc = eina_future_cb_log_err(.prefix = "prefix", .suffix = "suffix");
See also
eina_future_cb_log_from_desc()

◆ eina_future_cb_log_info

#define eina_future_cb_log_info (   _prefix,
  _suffix 
)
Value:
__FUNCTION__, EINA_LOG_LEVEL_INFO, EINA_LOG_DOMAIN_DEFAULT, __LINE__})
Eina_Future_Desc eina_future_cb_log_from_desc(const Eina_Future_Cb_Log_Desc desc)
Creates an Eina_Future_Desc that will log the previous future resolved value.
Definition: eina_promise.c:1475
#define EINA_LOG_DOMAIN_DEFAULT
This macro defines the domain to use with the macros EINA_LOG_DOM_DBG(), EINA_LOG_DOM_INFO(), EINA_LOG_DOM_WARN(), EINA_LOG_DOM_ERR() and EINA_LOG_DOM_CRIT().
Definition: eina_log.h:284
This struct is used by eina_future_cb_log_from_desc() and its contents will be routed to eina_log_pri...
Definition: eina_promise.h:371
Information log level.
Definition: eina_log.h:460

A syntactic sugar over eina_future_cb_log_from_desc().

This macro will set the following fields of the #Eina_Future_Cb_Log_Desc:

Usage:

desc = eina_future_cb_log_info(.prefix = "prefix", .suffix = "suffix");
See also
eina_future_cb_log_from_desc()

◆ eina_future_cb_log_warn

#define eina_future_cb_log_warn (   _prefix,
  _suffix 
)
Value:
__FUNCTION__, EINA_LOG_LEVEL_WARN, EINA_LOG_DOMAIN_DEFAULT, __LINE__})
Eina_Future_Desc eina_future_cb_log_from_desc(const Eina_Future_Cb_Log_Desc desc)
Creates an Eina_Future_Desc that will log the previous future resolved value.
Definition: eina_promise.c:1475
#define EINA_LOG_DOMAIN_DEFAULT
This macro defines the domain to use with the macros EINA_LOG_DOM_DBG(), EINA_LOG_DOM_INFO(), EINA_LOG_DOM_WARN(), EINA_LOG_DOM_ERR() and EINA_LOG_DOM_CRIT().
Definition: eina_log.h:284
This struct is used by eina_future_cb_log_from_desc() and its contents will be routed to eina_log_pri...
Definition: eina_promise.h:371
Warning log level.
Definition: eina_log.h:459

A syntactic sugar over eina_future_cb_log_from_desc().

This macro will set the following fields of the #Eina_Future_Cb_Log_Desc:

Usage:

desc = eina_future_cb_log_warn(.prefix = "prefix", .suffix = "suffix");
See also
eina_future_cb_log_from_desc()

◆ eina_future_then_easy

#define eina_future_then_easy (   _prev,
  ... 
)    eina_future_then_from_desc(_prev, eina_future_cb_easy(__VA_ARGS__))

A syntactic sugar over eina_future_then() and eina_future_cb_easy().

Usage:

f = eina_future_then_easy(f, .success = _success_cb, .success_type = EINA_VALUE_TYPE_DOUBLE, .data = NULL, );
See also
eina_future_then_from_desc()
eina_future_easy()
eina_future_then()
eina_future_cb_easy_from_desc()

Referenced by elm_cnp_selection_set().

◆ eina_future_chain_easy

#define eina_future_chain_easy (   _prev,
  ... 
)    eina_future_chain_easy_array(_prev, (Eina_Future_Cb_Easy_Desc[]) {__VA_ARGS__, {NULL, NULL, NULL, NULL, NULL}})

A syntactic sugar over eina_future_chain() and eina_future_cb_easy().

Usage:

f = eina_future_chain_easy(f, {.success = _success_cb, .success_type = EINA_VALUE_TYPE_DOUBLE, .data = NULL},
{ .success = _success2_cb }, {.error = error_cb});
See also
eina_future_chain_array()
eina_future_easy()
eina_future_chain_easy_array()
eina_future_cb_easy_from_desc()

Function Documentation

◆ eina_future_desc_flush()

void eina_future_desc_flush ( Eina_Future_Desc desc)

Flushes an #Eina_Future_Desc.

This function is mainly used by bindings to flush a #Eina_Future_Desc. It will call the Eina_Future_Cb with ENOMEM and zero the desc contents.

Parameters
[in,out]descThe #Eina_Future_Desc to flush, if NULL this is a noop.

◆ eina_future_cb_easy_desc_flush()

void eina_future_cb_easy_desc_flush ( Eina_Future_Cb_Easy_Desc desc)

Flushes an #Eina_Future_Cb_Easy_Desc.

This function is mainly used by bindings to flush a #Eina_Future_Cb_Easy_Desc. It will call the Eina_Future_Error_Cb with ENOMEM, the Eina_Future_Free_Cb and zero the desc contents.

Parameters
[in,out]descThe #Eina_Future_Cb_Easy_Desc to flush, if NULL this is a noop.

References _Eina_Future_Cb_Easy_Desc::data, EINA_UNUSED, eina_value_flush(), _Eina_Future_Cb_Easy_Desc::error, and _Eina_Future_Cb_Easy_Desc::free.

◆ eina_promise_as_value()

Eina_Value eina_promise_as_value ( Eina_Promise *  p)

Creates a new Eina_Value from a promise.

This function creates a new Eina_Value that will store a promise in it. This function is useful for dealing with promises inside a Eina_Future_Cb. By returning a Promise Eina_Value the whole chain will wait until the promise is resolved in order to continue its execution. Example:

static Eina_Value
_file_data_ready(const *data EINA_UNUSED, const Eina_Value v, const Eina_Future *dead EINA_UNUSED)
{
const char *file_data;
Eina_Promise *p;
// It was not possible to fetch the file size.
{
eina_value_get(&v, &err);
fprintf(stderr, "Could get the file data. Reason: %s\n", eina_error_msg_get(err));
return v;
}
{
fprintf(stderr, "Expecting type '%s' - received '%s'\n", EINA_VALUE_TYPE_STRING->name, v.type->name);
return v;
}
eina_value_get(&v, &file_data);
// count_words will count the words in the background and resolve the promise once it is over...
p = count_words(file_data);
}
static Eina_Value
_word_count_ready(const *data EINA_UNUSED, const Eina_Value v, const Eina_Future *dead EINA_UNUSED)
{
// The _word_count_ready will only be called once count_words() resolves/rejects the promise returned by _file_data_ready()
int count;
{
eina_value_get(&v, &err);
fprintf(stderr, "Could not count the file words. Reason: %s\n", eina_error_msg_get(err));
return v;
}
else if (v.type != EINA_VALUE_TYPE_INT)
{
fprintf(stderr, "Expecting type '%s' - received '%s'\n", EINA_VALUE_TYPE_INT->name, v.type->name);
return v;
}
eina_value_get(&v, &count);
printf("File word count %d\n", count);
return v;
}
void
file_operation(void)
{
Eina_Future *f = get_file_data("/MyFile.txt");
eina_future_chain(f, {.cb = _file_data_ready, .data = NULL},
{.cb = _word_count_ready, .data = NULL});
}
Parameters
[in,out]pThe promise obect to create the value from.
Returns
An Eina_Value. On error the value's type will be NULL.
Note
If an error happens the promise will be CANCELED.
See also
eina_future_as_value()
eina_promise_reject()
eina_promise_resolve()

References EINA_VALUE_EMPTY, and eina_value_setup().

◆ eina_future_as_value()

Eina_Value eina_future_as_value ( Eina_Future *  f)

Creates an Eina_Value from a future.

This function is used for the same purposes as eina_promise_as_value(), but receives an Eina_Future instead.

Parameters
[in,out]fA future to create a Eina_Value from.
Returns
An Eina_Value. On error the value's type will be NULL.
Note
If an error happens the future f will be CANCELED
See also
eina_promise_as_value()

References EINA_VALUE_EMPTY.

◆ eina_future_new()

Eina_Future* eina_future_new ( Eina_Promise *  p)

Creates a new future.

This function creates a new future and can be used to report that an operation has succeeded or failed using eina_promise_resolve() or eina_promise_reject().

Futures can also be canceled using eina_future_cancel(), which will cause the whole chain to be canceled alongside with any pending promise.

Note
A promise can only have one future attached to it, calling eina_future_new() on the same promise twice will result in an error (NULL is returned) and the future attached to the promise will be canceled!
Parameters
[in,out]pA promise used to attach a future. May not be NULL.
Returns
The future or NULL on error.
Note
If an error happens this function will CANCEL the promise.
See also
eina_promise_new()
eina_promise_reject()
eina_promise_resolve()
eina_future_cancel()

References _Eina_Future_Desc::cb.

Referenced by eina_future_all_array(), and eina_future_race_array().

◆ eina_future_resolved()

Eina_Future* eina_future_resolved ( Eina_Future_Scheduler scheduler,
Eina_Value  value 
)

Creates a new future that is already resolved to a value.

This function creates a new future with an already known value, that will be resolved and dispatched by the given scheduler as usual.

This is a helper that behaves the same as eina_promise_new() followed by eina_future_new() and then eina_promise_resolve().

Futures can also be canceled using eina_future_cancel(), which will cause the whole chain to be canceled alongside with any pending promise.

Parameters
[in,out]schedulerThe scheduler to use.
[in]valueThe value to be delivered. Note that the value contents must survive this function scope, that is, do not use stack allocated blobs, arrays, structures or types that keep references to memory you give. Values will be automatically cleaned up using eina_value_flush() once they are unused (no more future or futures returned a new value).
Returns
The future or NULL on error.
See also
eina_promise_new()
eina_future_new()
eina_promise_reject()
eina_promise_resolve()
eina_future_cancel()

◆ eina_future_rejected()

Eina_Future* eina_future_rejected ( Eina_Future_Scheduler scheduler,
Eina_Error  err 
)

Creates a new future that is already rejected to a specified error.

This function creates a new future with an already known error, that will be resolved and dispatched by the given scheduler as usual.

This is a helper that behaves the same as eina_promise_new() followed by eina_future_new() and then eina_promise_rejected().

Futures can also be canceled using eina_future_cancel(), which will cause the whole chain to be canceled alongside with any pending promise.

Parameters
[in,out]schedulerThe scheduler to use.
[in]errAn Eina_Error value
Returns
The future or NULL on error.
See also
eina_promise_new()
eina_future_new()
eina_promise_reject()
eina_promise_resolve()
eina_future_cancel()

◆ eina_future_then_from_desc()

Eina_Future* eina_future_then_from_desc ( Eina_Future *  prev,
const Eina_Future_Desc  desc 
)

Register an Eina_Future_Desc to be used when the future is resolve/rejected.

With this function a callback and data is attached to the future and then once it's resolved or rejected the callback will be informed.

If during the future creation an error happens this function will return NULL, and the Eina_Future_Desc::cb will be called reporting an error (EINVAL or ENOMEM), so the user has a chance to free Eina_Future_Desc::data.

In case a future in the chain is canceled, the whole chain will be canceled immediately and the error ECANCELED will be reported.

Here's a simple usage of this function.

static Eina_Value
_file_ready(const *data, const Eina_Value v, const Eina_Future *dead EINA_UNUSED)
{
Ctx *ctx = data;
// It was not possible to fetch the file size.
{
eina_value_get(&v, &err);
fprintf(stderr, "Could not read the file size. Reason: %s\n", eina_error_msg_get(err));
return v;
}
else if (v.type != EINA_VALUE_TYPE_INT)
{
fprintf(stderr, "Expecting type '%s' - received '%s'\n", EINA_VALUE_TYPE_INT->name, v.type->name);
return v;
}
eina_value_get(&v, &ctx->size);
printf("File size is %d bytes\n", ctx->size);
return v;
}
void
file_operation(void)
{
Eina_Future *f = get_file_size_async("/MyFile.txt");
eina_future_then_from_desc(f, (const Eina_Future_Desc){.cb = _size_ready, .data = NULL});
// There's a helper macro called eina_future_then() which simplifies the usage.
// The code below has the same effect.
// eina_future_then(f, _size_ready, NULL);
}

Although the code presented at _size_ready() is very simple, most of it is just used to check the Eina_Value type. In order to avoid this type of code the function eina_future_cb_easy_from_desc() was created. Please, check its documentation for more information.

This function can also be used to create a future chain, making it possible to execute the future result in a cascade order. When using a future chain the Eina_Value returned by a Eina_Future_Desc::cb will be delivered to the next Eina_Future_Desc::cb in the chain.

Here's an example:

static Eina_Value _future_cb1(const *data EINA_UNUSED, const Eina_Value v) { Eina_Value new_v; int i;

// There's no need to check the Eina_Value type since we're using eina_future_cb_easy() eina_value_get(&v, &i); printf("File size as int: %d\n", i); eina_value_setup(&new_v, EINA_VALUE_TYPE_STRING); // Convert the file size to string eina_value_convert(&v, &new_v); return new_v; }

static Eina_Value _future_cb2(const *data EINA_UNUSED, const Eina_Value v) { Eina_Value new_v; const char *file_size_str;

// There's no need to check the Eina_Value type since we're using eina_future_cb_easy() eina_value_get(&v, &file_size_str); printf("File size as string: %s\n", file_size_str); eina_value_setup(&new_v, EINA_VALUE_TYPE_DOUBLE); eina_value_convert(&v, &new_v); return new_v; }

static Eina_Value _future_cb3(const *data EINA_UNUSED, const Eina_Value v) { double d;

// There's no need to check the Eina_Value type since we're using eina_future_cb_easy() eina_value_get(&v, &d); printf("File size as double: %g\n", d); return v; }

static Eina_Value _future_err(void *data EINA_UNUSED, Eina_Error err) { // This function is called if future result type does not match or another error occurred Eina_Value new_v; eina_value_setup(&new_v, EINA_VALUE_TYPE_ERROR); eina_value_set(&new_v, err); fprintf(stderr, "Error during future process. Reason: %s\n", eina_error_msg_get(err)); // Pass the error to the next future in the chain.. return new_v; }

void chain(void)
{
Eina_Future *f = get_file_size_async("/MyFile.txt");
f = eina_future_then_easy(f, .success = _future_cb1, .success_type = EINA_VALUE_TYPE_INT);
// _future_cb2 will be executed after _future_cb1()
f = eina_future_then_easy(f, .success = _future_cb2, .success_type = EINA_VALUE_TYPE_STRING);
// _future_cb3 will be executed after _future_cb2()
f = eina_future_then_easy(f, .success = _future_cb3, .success_type = EINA_VALUE_TYPE_DOUBLE);
// If an error happens _future_err will be called
eina_future_then_easy(f, .error = _future_err);
}

Although it's possible to create a future chain using eina_future_then()/eina_future_then_from_desc() there's a function that makes this task much easier, please check eina_future_chain_array() for more information.

Note
This example does manual conversion and print, however we offer eina_future_cb_convert_to() and eina_future_cb_console_from_desc() and to make those common case easier.
Parameters
[in,out]prevA future to link against
[in]descA description struct containing the callback and data.
Returns
A new future or NULL on error.
Note
If an error happens the whole future chain will CANCELED and desc.cb will be called in order to free desc.data.
See also
eina_future_new()
eina_future_then()
#Eina_Future_Desc
eina_future_chain_array()
eina_future_chain()
eina_future_cb_console_from_desc()
eina_future_cb_easy_from_desc()
eina_future_cb_easy()
eina_future_cb_convert_to()
eina_future_cancel()
eina_future_then_easy()
eina_future_cb_log_from_desc()

Referenced by efl_future_chain_array().

◆ eina_future_cb_log_from_desc()

Eina_Future_Desc eina_future_cb_log_from_desc ( const Eina_Future_Cb_Log_Desc  desc)

Creates an Eina_Future_Desc that will log the previous future resolved value.

This function can be used to quickly log the value that an Eina_Future_Desc::cb is returning. The returned value will be passed to the next future in the chain without modifications.

There are some helper macros like eina_future_cb_log_dbg() which will automatically fill the following fields:

Parameters
[in]descThe description data to be used.
Returns
An #Eina_Future_Desc
See also
#Eina_Future_Cb_Log_Desc
efl_future_then()
efl_future_chain()
eina_future_cb_log_dbg()
eina_future_cb_log_crit()
eina_future_cb_log_err()
eina_future_cb_log_info()
eina_future_cb_log_warn()
eina_future_cb_console_from_desc()

◆ eina_future_chain_array()

Eina_Future* eina_future_chain_array ( Eina_Future *  prev,
const Eina_Future_Desc  descs[] 
)

Creates a future chain.

This behaves exactly like eina_future_then_from_desc(), but makes it easier to create future chains.

If during the future chain creation an error happens this function will return NULL, and the Eina_Future_Desc::cb from the descs array will be called reporting an error (EINVAL or ENOMEM), so the user has a chance to free Eina_Future_Desc::data.

Just like eina_future_then_from_desc(), the value returned by a Eina_Future_Desc::cb callback will be delivered to the next Eina_Future_Desc::cb in the chain.

In case a future in the chain is canceled, the whole chain will be canceled immediately and the error ECANCELED will be reported.

Here's an example:

// callbacks code....
Eina_Future* chain(void)
{
Eina_Future *f = get_file_size_async("/MyFile.txt");
return eina_future_chain(f, eina_future_cb_easy(_future_cb1, _future_err, NULL, EINA_VALUE_TYPE_INT, NULL),
eina_future_cb_easy(_future_cb2, _future_err, NULL, EINA_VALUE_TYPE_STRING, NULL),
eina_future_cb_easy(_future_cb3, _future_err, NULL, EINA_VALUE_TYPE_DOUBLE, NULL),
{.cb = _future_cb4, .data = NULL });
}
Parameters
[in,out]prevThe previous future
[in]descsAn array of descriptions. The last element of the array must have the Eina_Future_Desc::cb set to NULL
Returns
A future or NULL on error.
Note
If an error happens the whole future chain will CANCELED and desc.cb will be called in order to free desc.data.
See also
eina_future_new()
eina_future_then()
#Eina_Future_Desc
eina_future_chain()
eina_future_cb_ignore_error()
eina_future_cb_console_from_desc()
eina_future_cb_log_from_desc()
eina_future_cb_easy_from_desc()
eina_future_cb_easy()
eina_future_then_from_desc()
eina_future_then_easy()
eina_future_cb_convert_to()

◆ eina_future_chain_easy_array()

Eina_Future* eina_future_chain_easy_array ( Eina_Future *  prev,
const Eina_Future_Cb_Easy_Desc  descs[] 
)

Wrapper around eina_future_chain_array() and eina_future_cb_easy_from_desc()

This functions makes it easier to use eina_future_chain_array() with eina_future_cb_easy_from_desc(), check the macro eina_future_chain_easy() for a syntax sugar.

Parameters
[in,out]prevThe previous future
[in]descsAn array of descriptions. The last element of the array must have the Eina_Future_Desc::cb set to NULL
Returns
A future or NULL on error.
Note
If an error happens the whole future chain will CANCELED and desc.cb will be called in order to free desc.data.
See also
eina_future_chain_easy()
eina_future_chain()
eina_future_cb_easy()
eina_future_chain_array()
eina_future_cb_easy_from_desc()

◆ eina_future_cb_console_from_desc()

Eina_Future_Desc eina_future_cb_console_from_desc ( const Eina_Future_Cb_Console_Desc  desc)

Creates an Eina_Future_Desc that will print the previous future resolved value.

This function can be used to quickly inspect the value that an Eina_Future_Desc::cb is returning. The returned value will be passed to the next future in the chain without modifications.

There's also a helper macro called eina_future_cb_console() which makes this function easier to use.

Example:

eina_future_chain(a_future, {.cb = cb1, .data = NULL},
//Inspect the cb1 value and pass to cb2 without modifications
eina_future_cb_console("cb1 value:"),
{.cb = cb2, .data = NULL},
//Inspect the cb2 value
eina_future_cb_console("cb2 value:", " cb2 value suffix\n"))
Parameters
[in]descDescription object with contextual information.
Returns
An #Eina_Future_Desc

The description object, desc, can (optionally) include a prefix, suffix, filename and function name. If these are NULL, empty strings ("") are used instead. If desc->suffix is provided, the '
' should be provided to ensure the printed string ends with a line feed.

See also
eina_future_then()
#Eina_Future_Desc
eina_future_chain()
eina_future_cb_easy_from_desc()
eina_future_cb_easy()
eina_future_then_from_desc()
eina_future_then_easy()
eina_future_cb_console()
eina_future_cb_ignore_error()
eina_future_cb_log_from_desc()

References _Eina_Future_Desc::cb, _Eina_Future_Desc::data, _Eina_Future_Cb_Console_Desc::prefix, and _Eina_Future_Cb_Console_Desc::suffix.

◆ eina_future_cb_ignore_error()

Eina_Future_Desc eina_future_cb_ignore_error ( Eina_Error  err)

Returns a #Eina_Future_Desc that ignores an error.

This function may be used if one wants to ignore an error. If the specified error happens an EINA_VALUE_EMPTY will be delivered to the next future in the chain.

Parameters
[in]errThe error to be ignored.
Afuture descriptor to be used with eina_future_then() or eina_future_chain()

◆ eina_future_cb_convert_to()

Eina_Future_Desc eina_future_cb_convert_to ( const Eina_Value_Type type)

Creates an #Eina_Future_Desc which will convert the the received eina value to a given type.

Parameters
[in]typeThe Eina_Value_Type to convert to.
Returns
An #Eina_Future_Desc
See also
eina_future_then()
#Eina_Future_Desc
eina_future_chain()
eina_future_cb_easy_from_desc()
eina_future_cb_easy()
eina_future_then_from_desc()
eina_future_then_easy()

References _Eina_Future_Desc::cb.

◆ eina_future_cb_easy_from_desc()

Eina_Future_Desc eina_future_cb_easy_from_desc ( const Eina_Future_Cb_Easy_Desc  desc)

Creates an #Eina_Future_Desc based on a #Eina_Future_Cb_Easy_Desc.

This function aims to be used in conjunction with eina_future_chain(), eina_future_then_from_desc() and friends and its main objective is to simplify error handling and Eina_Value type checks. It uses three callbacks to inform the user about the future's result and life cycle. They are:

  • Eina_Future_Cb_Easy_Desc::free: Called after the future was freed and any resources allocated must be freed at this point. This callback is always called.

Check the example below for a sample usage:

static Eina_Value
_file_size_ok(void *data, Eina_Value v)
{
Ctx *ctx = data;
// Since an Eina_Future_Cb_Easy_Desc::success_type was provided, there's no need to check the value type
int s;
eina_value_get(&v, &s);
printf("File size is %d bytes\n", s);
ctx->file_size = s;
return v;
}
static Eina_Value
_file_size_err(void *data, Eina_Error err)
{
fprintf(stderr, "Could not read the file size. Reason: %s\n", eina_error_msg_get(err));
// Stop propagating the error.
}
static void
_future_freed(void *data, const Eina_Future dead)
{
Ctx *ctx = data;
printf("Future %p deleted\n", dead);
ctx->file_size_handler_cb(ctx->file_size);
free(ctx);
}
@code
void do_work(File_Size_Handler_Cb cb)
{
Ctx *ctx = malloc(sizeof(Ctx));
ctx->f = get_file_size("/tmp/todo.txt");
ctx->file_size = -1;
ctx->file_size_handler_cb = cb;
eina_future_then_easy(f, _file_size_ok, _file_size_err, _future_freed, EINA_VALUE_TYPE_INT, ctx);
}
Parameters
[in]descThe easy callback's description.
Returns
An #Eina_Future_Desc
See also
eina_future_chain()
eina_future_then()
eina_future_cb_easy()

◆ eina_promise_all_array()

Eina_Promise* eina_promise_all_array ( Eina_Future *  array[])

Creates an all promise.

Creates a promise that is resolved once all the futures from the array are resolved. The promise is resolved with an Eina_Value type array which contains EINA_VALUE_TYPE_VALUE elements. The result array is ordered according to the array argument. Example:

static const char *
_get_operation_name_by_index(int idx)
{
switch (idx)
{
case 0: return "Get file data";
case 1: return "Get file size";
default: return "sum";
}
}
static Eina_Value
_all_cb(const void *data EINA_UNUSED, const Eina_Value array, const Eina_Future *dead EINA_UNUSED)
{
unsigned int i, len;
{
eina_value_get(&array, &err);
fprintf(stderr, "Could not complete all operations. Reason: %s\n", eina_error_msg_get(err));
return array;
}
len = eina_value_array_count(&array);
for (i = 0; i < len; i++)
{
eina_value_array_get(&array, i, &v);
{
eina_value_get(&v, &err);
fprintf(stderr, "Could not complete operation '%s'. Reason: %s\n", _get_operation_name_by_index(i), eina_error_msg_get(err));
continue;
}
if (!i)
{
const char *msg;
{
fprintf(stderr, "Operation %s expects '%s' - received '%s'\n", _get_operation_name_by_index(i), EINA_VALUE_TYPE_STRING->name, v.type->name);
continue;
}
eina_value_get(&v, &msg);
printf("File content:%s\n", msg);
}
else if (i == 1)
{
int i;
{
fprintf(stderr, "Operation %s expects '%s' - received '%s'\n", _get_operation_name_by_index(i), EINA_VALUE_TYPE_INT->name, v.type->name);
continue;
}
eina_value_get(&v, &i);
printf("File size: %d\n", i);
}
else
{
double p;
{
fprintf(stderr, "Operation %s expects '%s' - received '%s'\n", _get_operation_name_by_index(i), EINA_VALUE_TYPE_DOUBLE->name, v.type->name);
continue;
}
eina_value_get(&v, &p);
printf("50 places of PI: %f\n", p);
}
}
return array;
}
void func(void)
{
Eina_Future *f1, *f2, *f3, f_all;
f1 = read_file("/tmp/todo.txt");
f2 = get_file_size("/tmp/file.txt");
// calculates 50 places of PI
f3 = calc_pi(50);
f_all = eina_future_all(f1, f2, f3);
eina_future_then(f_all, _all_cb, NULL);
}
Parameters
[in,out]arrayAn array of futures, EINA_FUTURE_SENTINEL terminated.
Returns
A promise or NULL on error.
Note
On error all the futures will be CANCELED.
See also
eina_future_all_array()

Referenced by eina_future_all_array().

◆ eina_promise_race_array()

Eina_Promise* eina_promise_race_array ( Eina_Future *  array[])

Creates a race promise.

Creates a promise that resolves when a future from the array is completed. The remaining futures will be canceled with the error code ECANCELED

The resulting value is an EINA_VALUE_TYPE_STRUCT with two fields:

  • A field named "value" which contains an Eina_Value with the result itself.
  • A field named "index" which is an int that contains the index of the completed function relative to the array;

Example.

static const char *
_get_operation_name_by_index(int idx)
{
switch (idx)
{
case 0: return "Get file data";
case 1: return "Get file size";
default: return "sum";
}
}
static Eina_Value
_race_cb(const void *data EINA_UNUSED, const Eina_Value v)
{
unsigned int i;
Eina_Value result;
// No need to check for the 'v' type. eina_future_cb_easy() did that for us.
// However we should check if the struct has the correct description
st = eina_value_memory_get(&v);
{
fprintf(stderr, "Eina_Value is not a race struct\n");
return v;
}
eina_value_struct_get(&v, "index", &i);
// Get the operation result
eina_value_struct_get(&v, "value", &result);
if (!i)
{
const char *msg;
fprintf(stderr, "Operation %s expects '%s' - received '%s'\n", _get_operation_name_by_index(i), EINA_VALUE_TYPE_STRING->name, result.type->name);
else
{
eina_value_get(&result, &msg);
printf("File content:%s\n", msg);
}
}
else if (i == 1)
{
int i;
if (result.type != EINA_VALUE_TYPE_INT)
fprintf(stderr, "Operation %s expects '%s' - received '%s'\n", _get_operation_name_by_index(i), EINA_VALUE_TYPE_INT->name, v.type->name);
else
{
eina_value_get(&result, &i);
printf("File size: %d\n", i);
}
}
else
{
double p;
fprintf(stderr, "Operation %s expects '%s' - received '%s'\n", _get_operation_name_by_index(i), EINA_VALUE_TYPE_DOUBLE->name, result.type->name);
else
{
eina_value_get(&result, &p);
printf("50 places of PI: %f\n", p);
}
}
eina_value_flush(&result);
return v;
}
static Eina_Value
_race_err(void *data, Eina_Error err)
{
fprintf(stderr, "Could not complete the race future. Reason: %s\n", eina_error_msg_get(err));
}
void func(void)
{
static const *Eina_Future[] = {NULL, NULL, NULL, NULL};
Eina_List *l = NULL;
futures[0] = read_file("/tmp/todo.txt");
futures[1] = get_file_size("/tmp/file.txt");
// calculates 50 places of PI
futures[2] = calc_pi(50);
f_race = eina_future_race_array(futures);
eina_future_then_easy(f_race, _race_cb, _race_err, NULL, EINA_VALUE_TYPE_STRUCT, NULL);
}
Parameters
[in,out]arrayAn array of futures, EINA_FUTURE_SENTINEL terminated.
Returns
A promise or NULL on error.
Note
On error all the futures will be CANCELED.
See also
eina_future_race_array()
_Eina_Future_Race_Result

Referenced by eina_future_race_array().

◆ eina_future_all_array()

static Eina_Future* eina_future_all_array ( Eina_Future *  array[])
inlinestatic

Creates a future that will be resolved once all futures from array is resolved.

This is a helper over eina_promise_all_array()

Parameters
[in,out]arrayA future array, must be terminated with EINA_FUTURE_SENTINEL
Returns
A future.
See also
eina_promise_all_array()
EINA_FUTURE_SENTINEL

References eina_future_new(), and eina_promise_all_array().

◆ eina_future_race_array()

static Eina_Future* eina_future_race_array ( Eina_Future *  array[])
inlinestatic

Creates a future that will be resolved once a future array is resolved.

This is a helper over eina_promise_race_array()

Parameters
[in,out]arrayA future array, must be terminated with EINA_FUTURE_SENTINEL
Returns
A future.
See also
eina_promise_race_array()
EINA_FUTURE_SENTINEL

References eina_future_new(), and eina_promise_race_array().

Variable Documentation

◆ EINA_PROMISE_RACE_STRUCT_DESC [1/2]

const Eina_Value_Struct_Desc* EINA_PROMISE_RACE_STRUCT_DESC

A pointer to the race struct description, which is used by eina_promise_race_array();.

This struct contains two members:

  • value An EINA_VALUE_TYPE_VALUE that contains the future result that wont the race.
  • index An EINA_VALUE_TYPE_UINT that contains the future index that won the race.
See also
eina_promise_race_array()
_Eina_Future_Race_Result

◆ EINA_PROMISE_RACE_STRUCT_DESC [2/2]

EINA_PROMISE_RACE_STRUCT_DESC = &RACE_STRUCT_DESC

A pointer to the race struct description, which is used by eina_promise_race_array();.

This struct contains two members:

  • value An EINA_VALUE_TYPE_VALUE that contains the future result that wont the race.
  • index An EINA_VALUE_TYPE_UINT that contains the future index that won the race.
See also
eina_promise_race_array()
_Eina_Future_Race_Result